Sample records for major ions volatile

  1. Major odorants released as urinary volatiles by urinary incontinent patients.

    PubMed

    Pandey, Sudhir Kumar; Kim, Ki-Hyun; Choi, Si On; Sa, In Young; Oh, Soo Yeon

    2013-01-01

    In this study, volatile urinary components were collected using three different types of samples from patients suffering from urinary incontinence (UI): (1) urine (A); (2) urine + non-used pad (B); and (3) urine + used pad (C). In addition, urine + non-used pad (D) samples from non-patients were also collected as a reference. The collection of urinary volatiles was conducted with the aid of a glass impinger-based mini-chamber method. Each of the four sample types (A through D) was placed in a glass impinger and incubated for 4 hours at 37 °C. Ultra pure air was then passed through the chamber, and volatile urine gas components were collected into Tedlar bags at the other end. These bag samples were then analyzed for a wide range of VOCs and major offensive odorants (e.g., reduced sulfur compounds (RSCs), carbonyls, trimethylamine (TMA), ammonia, etc.). Among the various odorants, sulfur compounds (methanethiol and hydrogen sulfide) and aldehydes (acetaldehyde, butylaldehyde, and isovaleraldehyde) were detected above odor threshold and predicted to contribute most effectively to odor intensity of urine incontinence. PMID:23823973

  2. Major Odorants Released as Urinary Volatiles by Urinary Incontinent Patients

    PubMed Central

    Pandey, Sudhir Kumar; Kim, Ki-Hyun; Choi, Si On; Sa, In Young; Oh, Soo Yeon

    2013-01-01

    In this study, volatile urinary components were collected using three different types of samples from patients suffering from urinary incontinence (UI): (1) urine (A); (2) urine + non-used pad (B); and (3) urine + used pad (C). In addition, urine + non-used pad (D) samples from non-patients were also collected as a reference. The collection of urinary volatiles was conducted with the aid of a glass impinger-based mini-chamber method. Each of the four sample types (A through D) was placed in a glass impinger and incubated for 4 hours at 37 °C. Ultra pure air was then passed through the chamber, and volatile urine gas components were collected into Tedlar bags at the other end. These bag samples were then analyzed for a wide range of VOCs and major offensive odorants (e.g., reduced sulfur compounds (RSCs), carbonyls, trimethylamine (TMA), ammonia, etc.). Among the various odorants, sulfur compounds (methanethiol and hydrogen sulfide) and aldehydes (acetaldehyde, butylaldehyde, and isovaleraldehyde) were detected above odor threshold and predicted to contribute most effectively to odor intensity of urine incontinence. PMID:23823973

  3. Integrated cation–anion\\/volatile fluid inclusion analysis by gas and ion chromatography; methodology and examples

    Microsoft Academic Search

    D. M. DeR Channer; C. J Bray; E. T. C Spooner

    1999-01-01

    Combined gas and ion chromatographic analysis of well characterized, small (?1 g) fluid inclusion-bearing samples is a powerful, but simple, means for obtaining integrated fluid concentrations of major and trace, volatile and ionic fluid constituents without using microthermometrically determined salinity for normalization. The methodology, which is described and assessed in detail, involves crushing a carefully cleaned sample at ?105°C in

  4. An inventory of major volatiles trapped in Ceres

    Microsoft Academic Search

    O. Mousis

    2004-01-01

    We determine the nature and the composition of ices incorporated in the interior of Ceres, assuming that icy planetesimals produced beyond 5 AU in the solar nebula took part in its formation (Cyr et al. 1998). We argue that volatiles were trapped under the forms of clathrate hydrates and hydrates in the outer solar nebula prior to have been incorporated

  5. Ion mobility spectrometry for detection of skin volatiles

    PubMed Central

    Ruzsanyi, Veronika; Mochalski, Pawel; Schmid, Alex; Wiesenhofer, Helmut; Klieber, Martin; Hinterhuber, Hartmann; Amann, Anton

    2012-01-01

    Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin. PMID:23217311

  6. The Performance of implied volatility in forecasting future volatility : an analysis of three major equity indices from 2004 to 2010

    E-print Network

    Ionesco, Vladimir M. (Vladimir Michae)

    2011-01-01

    In this thesis, we investigate whether implied volatility is an efficient estimator of future one-month volatility from an informational perspective and whether it outperforms historical volatility in this regard. We first ...

  7. Volatile signals of the major histocompatibility complex in male mouse?urine

    PubMed Central

    Singer, Alan G.; Beauchamp, Gary K.; Yamazaki, Kunio

    1997-01-01

    Variation in the genes of the major histocompatibility complex (MHC) contributes to unique individual odors (odortypes) in mice, as demonstrated by the ability of trained mice in a Y-maze olfactometer to discriminate nearly identical inbred mice that differ genetically only at the MHC (MHC congenic mice), while they cannot distinguish genetically identical inbred mice. Similar distinctions are possible with urine, a substance that is involved in many facets of mouse chemical communication. This paper reports results supporting the hypothesis that the MHC-determined urinary odor is composed of a mixture of volatile carboxylic acids occurring in relative concentrations that are characteristic of the odortype. Y-maze behavioral testing of urine fractions from anion exchange chromatography indicates that volatile acids are necessary and sufficient to convey MHC odortype information. Diethyl ether extracts, which are expected to contain the more volatile, less polar organic acids, were also discriminable in the Y-maze olfactometer. Ether extracts of 12 different urine samples from each of two panels of MHC congenic mice were analyzed by gas chromatography. No compounds unique to urine of either genotype were detected, but compounds did appear to occur in characteristic ratios in most of the samples of each type. Nonparametric statistical analysis of the gas chromatographic data showed that eight of the peaks occurred in significantly different relative concentrations in the congenic samples. One of the peaks was shown to represent phenylacetic acid, which has implications for the mechanism of the MHC specification of odortype. PMID:9122173

  8. MAJOR ION CHEMISTRY OF LAKES ON THE KENAI PENINSULA, ALASKA

    EPA Science Inventory

    A probability sample of 59 lakes was conducted in August, 1988 to characterize the major ion chemistry of a population of over 800 lakes on the Kenai Peninsula, AK. here were two groups of lakes: those with alkalinity ...

  9. Acceleration of beam ions during major radius compression in TFTR

    SciTech Connect

    Wong, K.L.; Bitter, M.; Hammett, G.W.; Heidbrink, W.; Hendel, H.; Kaita, R.; Scott, S.; Strachan, J.D.; Tait, G.; Bell, M.G.

    1985-09-01

    Tangentially co-injected deuterium beam ions were accelerated from 82 keV up to 150 keV during a major radius compression experiment in TFTR. The ion energy spectra and the variation in fusion yield were in good agreement with Fokker-Planck code simulations. In addition, the plasma rotation velocity was observed to rise during compression.

  10. Assessment of ambient volatile organic compounds (VOCs) near major roads in urban Nanjing, China

    NASA Astrophysics Data System (ADS)

    Wang, P.; Zhao, W.

    2008-08-01

    Volatile organic compounds (VOCs) are a major component of atmospheric pollutants in Nanjing, a large city in the east of China. Accordingly, 12-h diurnal monitoring for ten consecutive days was performed adjacent to major roads in five districts, ca.1.5 m above ground level, in April, July and October 2006, and January 2007. The most numerous species of VOCs (benzene, toluene, ethylbenzene, m/ p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, tetrachloromethane, trichloroethane and tetrachloroethane) were selected as the target pollutants for this field study of atmospheric distribution. The eleven VOCs were mostly found in gas phase due to their high vapor pressures. Gas-phase concentrations ranged between 0.6 and 67.9 ?g m - 3 . Simultaneously, the levels of those VOCs measured near major roads were associated slightly with their regional background level. For all these areas, as expected, the high traffic area was the highest in terms of concentration. A positive correlation was also found between the VOC levels and traffic density. Our studies also provided VOC distribution, and vertical/horizontal profiles. The results show that traffic-related exposure to VOCs in major road microenvironments is higher than elsewhere and poses a potential threat to pedestrians, commuters, and traffic-exposed workers.

  11. Determination of volatile biogenic amines in muscle food products by ion mobility spectrometry

    Microsoft Academic Search

    Zeev Karpas; Boris Tilman; Rachel Gdalevsky; Avraham Lorber

    2002-01-01

    The extent of spoilage of muscle food products was determined through measurement of volatile biogenic amines that emanated from food samples. The release of the amines was enhanced by addition of a few drops of an alkaline solution and the amines were monitored by ion mobility spectrometry (IMS). The limit of detection of the method for trimethylamine (TMA) was 2ng

  12. Liquid secondary ion mass spectrometry of volatile amines

    SciTech Connect

    Todd, P.J.

    1987-01-01

    The relationship between an octylamine concentration, primary ion current density and the relative intensity of secondary protonated octylamine peaks in the secondary ion mass spectra of octylamine/glycerol solutions is reported. The relation between the intensity of protonated octylamine and the pressure of octylamine being introduced onto the surface of glycerol that was being irradiated by 5 keV Ar/sup +/ primary ions at constant current density was determined. A second series of experiments was done in which the amine pressure was held constant, and the relative intensity of protonated octylamine was measured at various primary ion current densities. This determined the relation between the relative intensity of protonated octylamine, (130/sup +/), and the primary ion current density at constant pressure. It was possible to extrapolate (130/sup +/) back to the point where the primary ion current density was zero. The surface concentration of octylamine is determined by Henry's Law, octylamine surface activity, and octylamine partial pressure. Henry's Law constants and octylamine surface activity in glycerol were determined separately. The octylamine concentration was calculated from the applied pressure at zero primary ion current density, and the relation between octylamine concentration and secondary protonated octylamine intensity. 3 figs.

  13. Ion-trap detection of volatile organic compounds in alveolar breath

    SciTech Connect

    Phillips, M.; Greenberg, J. (Department of Medicine, St. Vincent's Medical Center of Richmond, Staten Island, NY (United States))

    1992-01-01

    We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated by two-stage cryofocusing, and assayed by gas chromatography with ion-trap detection. Compounds are identified by reference to a computer-based library of mass spectra with subtraction of the background components present in the inspired air. We used this device to study 10 normal subjects and determined the relative abundance of the volatile organic compounds in their alveolar breath. The breath-collecting apparatus was convenient to operate and was well tolerated by human volunteers.

  14. Effects of light and copper ions on volatile aldehydes of milk and milk fractions

    SciTech Connect

    Jeno, W.; Bassette, R.; Crang, R.E.

    1988-09-01

    Raw, laboratory-pasteurized and plant-pasteurized homogenized milks were exposed to copper ions (5 ppm), to sunlight or fluorescent light and the effects determined on the composition of volatile aldehydes. The greatest change due to copper treatment was an increase in n-hexanal; acetaldehyde showed the least response in each of the sources of milk. The responses were similar from all three sources of milk with laboratory-pasteurized milk samples showing the greatest responses for each aldehyde analyzed. Similar milk samples exposed to sunlight also showed an increase in volatile aldehydes from all milk sources but with the greatest response being acetaldehyde and n-pentanal components. The milk fraction most susceptible to changes in the presence of light was neutralized whey, whereas resuspended cream was most susceptible to copper exposure. Overall, dialyzed whey appeared to be influenced more than other milk fractions by both light and copper ions.

  15. Four terpene synthases produce major compounds of the gypsy moth feeding-induced volatile blend of Populus trichocarpa.

    PubMed

    Danner, Holger; Boeckler, G Andreas; Irmisch, Sandra; Yuan, Joshua S; Chen, Feng; Gershenzon, Jonathan; Unsicker, Sybille B; Köllner, Tobias G

    2011-06-01

    After herbivore damage, many plants increase their emission of volatile compounds, with terpenes usually comprising the major group of induced volatiles. Populus trichocarpa is the first woody species with a fully sequenced genome, enabling rapid molecular approaches towards characterization of volatile terpene biosynthesis in this and other poplar species. We identified and characterized four terpene synthases (PtTPS1-4) from P. trichocarpa which form major terpene compounds of the volatile blend induced by gypsy moth (Lymantria dispar) feeding. The enzymes were heterologously expressed and assayed with potential prenyl diphosphate substrates. PtTPS1 and PtTPS2 accepted only farnesyl diphosphate and produced (-)-germacrene D and (E,E)-?-farnesene as their major products, respectively. In contrast, PtTPS3 and PtTPS4 showed both mono- and sesquiterpene synthase activity. They produce the acyclic terpene alcohols linalool and nerolidol but exhibited opposite stereospecificity. qRT-PCR analysis revealed that the expression of the respective terpene synthase genes was induced after feeding of gypsy moth caterpillars. The TPS enzyme products may play important roles in indirect defense of poplar to herbivores and in mediating intra- and inter-plant signaling. PMID:21492885

  16. Enantiomer distribution of major chiral volatile organic compounds in selected types of herbal honeys.

    PubMed

    Pažitná, Alexandra; Džúrová, Jana; Spánik, Ivan

    2014-10-01

    In this article, volatile organic compounds in 14 honey samples (rosemary, eucalyptus, orange, thyme, sage, and lavender) were identified. Volatile organic compounds were extracted using a solid phase microextraction method followed by gas chromatography connected with mass spectrometry analysis. The studied honey samples were compared based on their volatile organic compounds composition. In total, more than 180 compounds were detected in the studied samples. The detected compounds belong to various chemical classes such as terpenes, alcohols, acids, aldehydes, ketones, esters, norisoprenoids, benzene and furane derivatives, and organic compounds containing sulfur and nitrogen heteroatom. Ten chiral compounds (linalool, trans-linalool oxide, cis-linalool oxide, 4-terpineol, ?-terpineol, hotrienol, and four stereoisomers of lilac aldehydes) were selected for further chiral separation. PMID:25099214

  17. Multi-Capillary Column-Ion Mobility Spectrometry of Volatile Metabolites Emitted by Saccharomyces Cerevisiae

    PubMed Central

    Halbfeld, Christoph; Ebert, Birgitta E.; Blank, Lars M.

    2014-01-01

    Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption–gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism, fast and non-invasive MCC-IMS analyses provide valuable data for process control. PMID:25197771

  18. A Volatile Organic Analyzer for Space Station - Description and evaluation of a gas chromatography\\/ion mobility spectrometer

    Microsoft Academic Search

    Thomas Limero; John Brokenshire; Colin Cumming; Ed Overton; Ken Carney; Jay Cross; Gary Eiceman; John James

    1992-01-01

    An on-board Volatile Organic Analyzer (VOA), an essential component of the Environmental Health System (EHS) air-quality monitoring strategy, is described. The strategy is aimed at warning the crew and ground personnel if volatile compounds exceed safe exposure limits. The VOA uses a combination of gas chromatography (GC) and ion-mobility spectrometry (IMS) for environmental monitoring and analysis. It is concluded that

  19. Studies of signal suppression in liquid chromatography–electrospray ionization mass spectrometry using volatile ion-pairing reagents

    Microsoft Academic Search

    Sven Åke Gustavsson; Jenny Samskog; Karin E. Markides; Bengt Långström

    2001-01-01

    Volatile ion-pairing reagents are useful due to their compatibility with liquid chromatography–electrospray ionization (ESI) mass spectrometry. In this study trifluoroacetic acid, heptafluorobutanoic acid and perfluoroheptanoic acid were used as ion-pairing reagents. The signal intensities of eight amine analytes were measured in the presence of these fluorinated carboxylic acids and compared with the signal intensity when using an ion-pair free formic

  20. Monitoring of polyaromatic hydrocarbons and volatile organic compounds in two major traffic tunnels in Seoul, Korea

    Microsoft Academic Search

    Ki-Hyun Kim; Ashish Anthwal; Chan Goo Park; Suk-Joo Jo; Young-Zoo Chae; Jin-A Park; Jong Heub Jung; Jong Ryeul Sohn; Jong-Min Oh

    2012-01-01

    To describe the fundamental aspects of air quality in tunnel environments, field campaigns were conducted to measure polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and some criteria pollutants from two tunnel sites of Nam San (NS) and Hong Ji (HJ) gates in Seoul, Korea. The total PAH values (ng m) for the NS tunnel (137.8±10.9) were notably higher than the

  1. A Volatile Organic Analyzer for Space Station - Description and evaluation of a gas chromatography/ion mobility spectrometer

    NASA Technical Reports Server (NTRS)

    Limero, Thomas; Brokenshire, John; Cumming, Colin; Overton, ED; Carney, Ken; Cross, Jay; Eiceman, Gary; James, John

    1992-01-01

    An on-board Volatile Organic Analyzer (VOA), an essential component of the Environmental Health System (EHS) air-quality monitoring strategy, is described. The strategy is aimed at warning the crew and ground personnel if volatile compounds exceed safe exposure limits. The VOA uses a combination of gas chromatography (GC) and ion-mobility spectrometry (IMS) for environmental monitoring and analysis. It is concluded that the VOA dual-mode detection capability and the ion mobilities in the drift region are unique features that can assist in the resolution of coeluting GC peaks. The VOA is capable of accurately identifying and quantifying target compounds in a complex mixture.

  2. Enantiomeric distribution of major chiral volatile organic compounds in juniper-flavored distillates.

    PubMed

    Pažitná, Alexandra; Spánik, Ivan

    2014-02-01

    The enantiomeric ratios of chiral volatile organic compounds in juniper-flavored spirits produced by various processing technologies in different EU countries were determined by multidimensional GC using solid-phase microextraction and liquid-liquid extraction as a sample pretreatment procedure. In total, more than 260 compounds were detected in studied spirits from which linalool, ?-terpineol, 4-terpineol, linalool oxides, ?-pinene, and verbenone were selected for enantiomeric separation. The significant differences in enantiomeric ratio of linalool and cis-linalool oxide allowed us to distinguish between samples produced in Slovakia and the United Kingdom from those produced in Germany, Czech Republic, and Belgium. The pure enantiomer of trans-linalool oxide was found only in samples from Germany. It was shown that the enantiomeric ratio is independent of the sample treatment procedure, and only small differences up to 1% were observed. PMID:24339334

  3. Nucleation and growth of atmospheric particles: Contribution of ion-mediated nucleation and role of low volatile organics condensation

    Microsoft Academic Search

    F. Yu; G. Luo

    2010-01-01

    Formation and subsequent growth of secondary particles is an important source of atmospheric aerosol and contributes significantly to climate effective aerosols. It is now generally accepted that H2SO4 and ions are involved in the nucleation process while low volatile organic gases (LV-SOG) and H2SO4 are involved in the growth process, although the relative contribution of ion versus neutral nucleation and

  4. Volatile evolution induced by energetic He ++ ions in a polyurethane and the effects of previous gamma irradiation

    Microsoft Academic Search

    J. J. Murphy; C. J. Wetteland

    2005-01-01

    Irradiation of polymer samples using an accelerated beam of He++ ions passed through a 10?m thick window of havar foil, has been performed. Such an irradiation simulates the effects of large ? radiation doses, on a vastly reduced time-scale. The experimental set up was designed to allow analysis of volatiles evolved from the irradiated samples by means of a residual

  5. Volatile Metabolites

    PubMed Central

    Rowan, Daryl D.

    2011-01-01

    Volatile organic compounds (volatiles) comprise a chemically diverse class of low molecular weight organic compounds having an appreciable vapor pressure under ambient conditions. Volatiles produced by plants attract pollinators and seed dispersers, and provide defense against pests and pathogens. For insects, volatiles may act as pheromones directing social behavior or as cues for finding hosts or prey. For humans, volatiles are important as flavorants and as possible disease biomarkers. The marine environment is also a major source of halogenated and sulfur-containing volatiles which participate in the global cycling of these elements. While volatile analysis commonly measures a rather restricted set of analytes, the diverse and extreme physical properties of volatiles provide unique analytical challenges. Volatiles constitute only a small proportion of the total number of metabolites produced by living organisms, however, because of their roles as signaling molecules (semiochemicals) both within and between organisms, accurately measuring and determining the roles of these compounds is crucial to an integrated understanding of living systems. This review summarizes recent developments in volatile research from a metabolomics perspective with a focus on the role of recent technical innovation in developing new areas of volatile research and expanding the range of ecological interactions which may be mediated by volatile organic metabolites. PMID:24957243

  6. Volatile metabolites.

    PubMed

    Rowan, Daryl D

    2011-01-01

    Volatile organic compounds (volatiles) comprise a chemically diverse class of low molecular weight organic compounds having an appreciable vapor pressure under ambient conditions. Volatiles produced by plants attract pollinators and seed dispersers, and provide defense against pests and pathogens. For insects, volatiles may act as pheromones directing social behavior or as cues for finding hosts or prey. For humans, volatiles are important as flavorants and as possible disease biomarkers. The marine environment is also a major source of halogenated and sulfur-containing volatiles which participate in the global cycling of these elements. While volatile analysis commonly measures a rather restricted set of analytes, the diverse and extreme physical properties of volatiles provide unique analytical challenges. Volatiles constitute only a small proportion of the total number of metabolites produced by living organisms, however, because of their roles as signaling molecules (semiochemicals) both within and between organisms, accurately measuring and determining the roles of these compounds is crucial to an integrated understanding of living systems. This review summarizes recent developments in volatile research from a metabolomics perspective with a focus on the role of recent technical innovation in developing new areas of volatile research and expanding the range of ecological interactions which may be mediated by volatile organic metabolites. PMID:24957243

  7. Volatile organic compound analysis by ion molecule reaction mass spectrometry for Gram-positive bacteria differentiation.

    PubMed

    Dolch, M E; Hornuss, C; Klocke, C; Praun, S; Villinger, J; Denzer, W; Schelling, G; Schubert, S

    2012-11-01

    Approximately 50 % of all clinically proven infections in critically ill patients are caused by Gram-positive bacteria. The timely and appropriate treatment of these infections is vital in order to avoid negative outcomes. Hence, fast and reliable methods are needed for the early detection and identification of microorganisms. Recently, direct mass spectrometry-based analysis of volatile organic compounds emitted by microorganisms has been employed to study Gram-negative bacteria. Here, we report a feasibility study of ion molecule reaction mass spectrometry (IMR-MS) for in vitro growth detection and species differentiation of selected Gram-positive bacteria that are frequently isolated in blood culture samples, namely, Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, and Staphylococcus epidermidis. Ion molecule reaction mass spectrometry was used to analyze the headspace above cultures containing Gram-positive bacteria incubated at 37 °C starting with 10(2) colony-forming units (CFU)/ml. Measurements to determine the presence of volatile organic compounds were performed 4, 8, and 24 h after incubation, respectively. The detection of microbial growth was accomplished already after 8 h in cultures containing E. faecalis. After 24 h of incubation, characteristic mass spectra were obtained for all species. Processing these mass spectra by hierarchic clustering and principal component analysis (PCA) enabled us to differentiate between bacterial species. IMR-MS in conjunction with a cumulative end-point model provides the means for rapid growth detection and differentiation of Gram-positive bacteria on the species level, typically within an analysis time of less than 3 min per sample. PMID:22782437

  8. VOLATILE ORGANIC COMPOUNDS IN 600 U.S. HOMES: MAJOR SOURCES OF PERSONAL EXPOSURE

    EPA Science Inventory

    The USEPA carried out the Total Exposure Assessment Methodology (TEAM) Study (1980-85) on 600 subjects in five cities representing a total population of more than 700,000 persons. Personal exposures to all prevalent target compounds exceeded outdoor concentrations. Major sources ...

  9. Correlation in price changes and volatility of major Latin American stock markets

    Microsoft Academic Search

    A. Christofi; A. Pericli

    1999-01-01

    This paper seeks to investigate the short-run dynamics between five major Latin American stock markets (Argentina, Brazil, Chile, Colombia and Mexico). Unlike previous research on these markets, the joint distribution of stock returns is estimated as a vector autoregression (VAR) with innovations following an exponential GARCH process. Our study is carried out using closing stock market prices covering the period

  10. Major ion toxicity of six produced waters to three freshwater species: Application of ion toxicity models and TIE procedures

    SciTech Connect

    Tietge, J.E.; Hockett, J.R. [ENSR Consulting and Engineering, Fort Collins, CO (United States); Evans, J.M. [Gas Research Inst., Chicago, IL (United States)

    1997-10-01

    Previous research to characterize the acute toxicity of major ions to freshwater organisms resulted in the development of statistical toxicity models for three freshwater species (Ceriodaphnia dubia, Pimephales promelas, and Daphnia magna). These ion toxicity models estimate the toxicity of seven major ions utilizing logistic regression. In this study, the ion toxicity models were used in conjunction with Phase 1 toxicity identification evaluation (TIE) procedures to evaluate the contribution of major ion toxicity to the total toxicity of six produced water samples ranging in total salinity from 1.7 to 58.1 g/L. Initial toxicities of all six samples were compared to the model predictions. Four produced waters were found to have toxicity consistent with toxicity attributable to major ion concentrations only. Two produced waters were found to exhibit more toxicity than expected from ion concentrations alone. These samples were subjected to Phase 1 TIE procedures. Toxicities were reduced by specific Phase 1 TIE manipulations to those predicted by the ion toxicity models. Mock effluents were used to verify the results. The combination of the ion toxicity models with Phase 1 TIE procedures successfully quantified the toxicity due to major ions in six produced water samples.

  11. Major ion toxicity in effluents: A review with permitting recommendations

    SciTech Connect

    Goodfellow, W.L.; Ausley, L.W.; Burton, D.T.; Denton, D.L.; Dorn, P.B.; Grothe, D.R.; Heber, M.A.; Norberg-King, T.J.; Rodgers, J.H. Jr.

    2000-01-01

    Effluent toxicity testing methods have been well defined, but for the most part, these methods do not attempt to segregate the effects of active ionic concentrations and ion imbalances upon test and species performances. The role of various total dissolved solids in effluents on regulatory compliance has emerged during the last few years and has caused confusion in technical assessment and in permitting and compliance issues. This paper assesses the issue of ionic strength and ion imbalance, provides a brief summary of applicable data, presents several case studies demonstrating successful tools to address toxicity resulting from salinity and ion imbalance, and provides recommendations for regulatory and compliance options to manage discharges with salinity/ion imbalance issues. Effluent toxicity resulting from inorganic ion imbalance and the ion concentration of the effluent is pervasive in permitted discharge from many industrial process and municipal discharges where process streams are concentrated, adjusted, or modified. This paper discusses procedures that use weight-of-evidence approaches to identify ion imbalance toxicity, including direct measurement, predictive toxicity models for freshwater, exchange resins, mock effluents, and ion imbalance toxicity with tolerant/susceptible test species. Cost-effective waste treatment control options for a facility whose effluent is toxic because of total dissolved solids (TDS) or because of specific ion(s) are scarce at best. Depending on the discharge situation, TDS toxicity may not be viewed with the same level of concern as other, more traditional, toxicants. These discharge situations often do not require the conservative safety factors required by other toxicants. Selection of the alternative regulatory solutions discussed in this paper may be beneficial, especially because they do not require potentially expensive or high-energy-using treatment options that may be ineffective control options. The information presented is intended to provide a better understanding of the role of ion imbalance in aquatic toxicity testing and to provide various recommendations that should be considered in addressing these issues.

  12. Determination of major element chemistry in terrestrial waters from Antarctica by ion chromatography

    Microsoft Academic Search

    K. A Welch; W. B Lyons; E Graham; K Neumann; J. M Thomas; D Mikesell

    1996-01-01

    As part of the new Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, a systematic aqueous geochemical sampling program has been undertaken. A series of terrestrial water samples have been collected and analyzed for major ion chemistry by ion chromatography. The concentrations of ions cover a wide range of total dissolved solids (TDS) from relatively

  13. Exposure to major volatile organic compounds and carbonyls in European indoor environments and associated health risk.

    PubMed

    Sarigiannis, Dimosthenis A; Karakitsios, Spyros P; Gotti, Alberto; Liakos, Ioannis L; Katsoyiannis, Athanasios

    2011-05-01

    This paper summarizes recent data on the occurrence of major organic compounds (benzene, toluene, xylenes, styrene, acetaldehyde, formaldehyde, naphthalene, limonene, ?-pinene and ammonia, classified by the European Commission's INDEX strategy report as the priority pollutants to be regulated) and evaluates accordingly cancer and non-cancer risks posed by indoor exposure in dwellings and public buildings in European Union (EU) countries. The review process indicated that significant differences in indoor air quality exist within and among the countries where data were available, indicating corresponding differences in sources and emission strength of airborne chemicals, identified or not. Conservative exposure limits were not exceeded for non-carcinogenic effects, except for formaldehyde; for carcinogenic agents the estimated risks were up to three orders of magnitude higher than the one (10(-6)) proposed as acceptable by risk management bodies. However, the risk assessment evaluation process faces crucial difficulties, either due to the relative paucity of indoor air quality measurements in many EU countries, or by the lack of sampling consistency in the already existing studies, indicating the need for additional measurements of indoor air quality following a harmonized sampling and analytical protocol. Additionally, uncertainties embodied in the cancer potency factors and exposure limit values impose further difficulties in substance prioritization and risk management. PMID:21354626

  14. Mass Size Distributions and Precursor Gas Concentrations of Major Inorganic Ions in'Antarctic Aerosol

    Microsoft Academic Search

    Risto Hillamo; Ivo Allegrini; Roberto Sparapani; Veli-Matti Kerminen

    1998-01-01

    Mass size distributions of major inorganic ions in aerosol particles and their atmospheric precursor gases were studied at Terra Nova Bay in Antarctica (74° 41? 42?S, 164° 05?36 ?E) between January 30 and February 18, 1995. The mass size distributions of sulphate, the major inorganic ion, had two submicron and two supermicron modes. The accumulation mode (average mass median diameter

  15. Major ion concentrations and the inorganic carbon chemistry of the Humber rivers

    Microsoft Academic Search

    Helen P. Jarvie; Colin Neal; David V. Leach; Geoffery P. Ryland; W. Alan House; Alice J. Robson

    1997-01-01

    Measurements of major ion concentrations in the main rivers draining into the Humber estuary show two dominant spatial patterns, related to anthropogenic sources from catchments draining urban\\/industrial areas and background weathering sources from the rural catchments. Most major ions exhibit dilution effects with flow, with higher concentrations at baseflow compared with stormflow conditions. This suggests a predominance of point (effluent)

  16. The major-ion composition of Carboniferous seawater

    NASA Astrophysics Data System (ADS)

    Holt, Nora M.; García-Veigas, Javier; Lowenstein, Tim K.; Giles, Peter S.; Williams-Stroud, Sherilyn

    2014-06-01

    The major-ion chemistry (Na+, Mg2+, Ca2+, K+, SO42-, and Cl-) of Carboniferous seawater was determined from chemical analyses of fluid inclusions in marine halites, using the cryo scanning electron microscopy (Cryo-SEM) X-ray energy-dispersive spectrometry (EDS) technique. Fluid inclusions in halite from the Mississippian Windsor and Mabou Groups, Shubenacadie Basin, Nova Scotia, Canada (Asbian and Pendleian Substages, 335.5-330 Ma), and from the Pennsylvanian Paradox Formation, Utah, USA, (Desmoinesian Stage 309-305 Ma) contain Na+-Mg2+-K+-Ca2+-Cl- brines, with no measurable SO42-, which shows that the Carboniferous ocean was a “CaCl2 sea”, relatively enriched in Ca2+ and low in SO42- with equivalents Ca2+ > SO42- + HCO3-. ?34S values from anhydrite in the Mississippian Shubenacadie Basin (13.2-14.0 ‰) and the Pennsylvanian Paradox Formation (11.2-12.6 ‰) support seawater sources. Br in halite from the Shubenacadie Basin (53-111 ppm) and the Paradox Basin (68-147 ppm) also indicate seawater parentages. Carboniferous seawater, modeled from fluid inclusions, contained ?22 mmol Ca2+/kg H2O (Mississippian) and ?24 mmol Ca2+/kg H2O (Pennsylvanian). Estimated sulfate concentrations are ?14 mmol SO42-/kg H2O (Mississippian), and ?12 mmol SO42-/kg H2O (Pennsylvanian). Calculated Mg2+/Ca2+ ratios are 2.5 (Mississippian) and 2.3 (Pennsylvanian), with an estimated range of 2.0-3.2. The fluid inclusion record of seawater chemistry shows a long period of CaCl2 seas in the Paleozoic, from the Early Cambrian through the Carboniferous, when seawater was enriched in Ca2+ and relatively depleted in SO42-. During this ?200 Myr interval, Ca2+ decreased and SO42- increased, but did not cross the Ca2+-SO42- chemical divide to become a MgSO4 sea (when SO42- in seawater became greater than Ca2+) until the latest Pennsylvanian or earliest Permian (?309-295 Ma). Seawater remained a MgSO4 sea during the Permian and Triassic, for ?100 Myr. Fluid inclusions also record a long interval, from the Early Cambrian to the Middle Devonian, when seawater had low Mg2+/Ca2+ ratios (<2) that coincide with calcite seas. The Mg2+/Ca2+ ratio of seawater rose from 0.9 in the Middle Devonian, to 2.5 in the Middle/Late Mississippian, 2.3 in the Middle Pennsylvanian, and 3.5 in the Early Permian. The transition from calcite seas to aragonite seas, established from the mineralogy of oölites and early marine cements, occurred in the Late Mississippian. Fluid inclusions show that seawater Mg2+/Ca2+ ratios rose above 2 by the Middle to Late Mississippian coinciding exactly with the shift to aragonite seas. Aragonite seas existed for ?100 Myr, from the Late Mississippian until the Late Triassic/Early Jurassic.

  17. The major volatile compound 2-phenylethanol from the biocontrol yeast, Pichia anomala, inhibits growth and expression of aflatoxin biosynthetic genes of Aspergillus flavus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus is a globally distributed fungus and an important food contaminant because it produces the most potent natural carcinogenic compound known as aflatoxin (AF) B1. The major volatile from a yeast strain, Pichia anomala WRL-076 was identified by SPEM-GC/MS analysis to be 2-phenylethan...

  18. Influence of extraction methodologies on the analysis of five major volatile aromatic compounds of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) grown in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infusions of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) have been commonly used in folk medicine in Thailand and other Asian countries. This study focuses on a systematic comparison of two extraction methods for major volatile aromatic compounds (VACs) of citronella g...

  19. Textural characterization, major and volatile element quantification and Ar-Ar systematics of spherulites in the Rocche Rosse obsidian flow, Lipari, Aeolian Islands: a temperature continuum growth model

    NASA Astrophysics Data System (ADS)

    Clay, P. L.; O'Driscoll, B.; Gertisser, R.; Busemann, H.; Sherlock, S. C.; Kelley, S. P.

    2013-02-01

    Spherulitic textures in the Rocche Rosse obsidian flow (Lipari, Aeolian Islands, Italy) have been characterized through petrographic, crystal size distribution (CSD) and in situ major and volatile elemental analyses to assess the mode, temperature and timescales of spherulite formation. Bulk glass chemistry and spherulite chemistry analyzed along transects across the spherulite growth front/glass boundary reveal major-oxide and volatile (H2O, CO2, F, Cl and S) chemical variations and heterogeneities at a ?5 ?m scale. Numerous bulk volatile data in non-vesicular glass (spatially removed from spherulitic textures) reveal homogenous distributions of volatile concentrations: H2O (0.089 ± 0.012 wt%), F (950 ± 40 ppm) and Cl (4,100 ± 330 ppm), with CO2 and S consistently below detection limits suggesting either complete degassing of these volatiles or an originally volatile-poor melt. Volatile concentrations across the spherulite boundary and within the spherulitic textures are highly variable. These observations are consistent with diffusive expulsion of volatiles into melt, leaving a volatile-poor rim advancing ahead of anhydrous crystallite growth, which is envisaged to have had a pronounced effect on spherulite crystallization dynamics. Argon concentrations dissolved in the glass and spherulites differ by a factor of ~20, with Ar sequestered preferentially in the glass phase. Petrographic observation, CSD analysis, volatile and Ar data as well as diffusion modeling support continuous spherulite nucleation and growth starting at magmatic (emplacement) temperatures of ~790-825 °C and progressing through the glass transition temperature range ( T g ~ 750-620 °C), being further modified in the solid state. We propose that nucleation and growth rate are isothermally constant, but vary between differing stages of spherulite growth with continued cooling from magmatic temperatures, such that there is an evolution from a high to a low rate of crystallization and low to high crystal nucleation. Based on the diffusion of H2O across these temperature ranges (~800-300 °C), timescales of spherulite crystallization occur on a timescale of ~4 days with further modification up to ~400 years (growth is prohibitively slow <400 °C and would become diffusion reliant). Selective deformation of spherulites supports a down-temperature continuum of spherulite formation in the Rocche Rosse obsidian; indeed, petrographic evidence suggests that high-strain zones may have catalyzed progressive nucleation and growth of further generations of spherulites during syn- and post-emplacement cooling.

  20. Ion-trap detection of volatile organic compounds in alveolar breath

    Microsoft Academic Search

    M. Phillips; J. Greenberg

    1992-01-01

    We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated

  1. Major ion chemistry of the Ganga source waters: Weathering in the high altitude Himalaya

    Microsoft Academic Search

    M. M. Sarin; S. Krishnaswami; J. R. Trivedi; K. K. Sharma

    1992-01-01

    A systematic study of the major ion chemistry of the Ganga source waters—the Bhagirathi, Alaknanda and their tributaries—has\\u000a been carried out to assess the chemical weathering processes in the high altitude Himalaya. Among major ions, Ca, Mg, HCO3 and SO4 are the most abundant in these river waters. These results suggest that weathering of carbonate rocks by carbonic and sulphuric

  2. Elevated major ion concentrations inhibit larval mayfly growth and development.

    PubMed

    Johnson, Brent R; Weaver, Paul C; Nietch, Christopher T; Lazorchak, James M; Struewing, Katherine A; Funk, David H

    2015-01-01

    Anthropogenic disturbances, including those from developing energy resources, can alter stream chemistry significantly by elevating total dissolved solids. Field studies have indicated that mayflies (Order Ephemeroptera) are particularly sensitive to high total dissolved solids. In the present study, the authors measured 20-d growth and survivorship of larval Neocloeon triangulifer exposed to a gradient of brine salt (mixed NaCl and CaCl2 ) concentrations. Daily growth rates were reduced significantly in all salt concentrations above the control (363?µS?cm(-1) ) and larvae in treatments with specific conductance >812?µS?cm(-1) were in comparatively earlier developmental stages (instars) at the end of the experiment. Survivorship declined significantly when specific conductance was >1513?µS?cm(-1) and the calculated 20-d 50% lethal concentration was 2866?µS?cm(-1) . The present study's results provide strong experimental evidence that elevated ion concentrations similar to those observed in developing energy resources, such as oil and gas drilling or coal mining, can adversely affect sensitive aquatic insect species. PMID:25307284

  3. Volatile production in nonice materials on Solar System bodies with tenuous atmospheres by ion bombardment - Laboratory results

    NASA Astrophysics Data System (ADS)

    Hibbitts, C. A.; Thevuthasan, S.; Shutthanandan, V.; Orlando, T.; Hansen, G. B.; McCord, T. B.

    2003-05-01

    Volatiles, inferred to be trapped in nonice materials, have been discovered on the Jovian satellites and in IDPs [McCord et al., 1998; Hibbitts et al., 2000; Flynn et al., 2002]. In general, these types of volatiles may be produced through high-energy ion bombardment of Solar System bodies that have tenuous atmospheres, from the Moon to the Saturnian satellites and beyond. The surfaces of these bodies are continually bombarded by a combination of cosmic, solar, and planetary magnetospheric radiation including UV, keV protons and Helium nuclei, and more massive keV to MeV ions. The Moon's surface contains Fe-oxides that may release water products under bombardment by solar wind protons. Many classes of asteroids and the outer planets' satellites appear to contain clays or other OH-bearing materials that could release water-products as well under bombardment. Also, organic material, likely present on surfaces other than the Moon, may participate in bombardment reactions to form carbon monoxide or dioxide. Results from our laboratory experiments conducted at the Environmental Molecular Sciences Laboratory (EMSL) accelerator facility, Pacific Northwest National Laboratory (PNNL) show that volatiles are produced during MeV ion irradiation of these types of materials. We bombarded clays, oxyhydroxides, ilmenite, and carbon-doped samples with MeV hydrogen, deuterium, oxygen, and sulfur ions at current densities of 100 to 1000 namps ( 1E12 to 1E13 ions/cm2/sec) over several minutes. Ohmic heating and outgassing of trapped atmospheric gases was minimal at the lower flux levels. Most of the irradiation effects are non-thermal and are due to ionization and momentum transfer processes. Proton or deuteron bombardment of ilmenite produces water-related molecules that are quickly released into the vacuum chamber and detected by mass spectrometry. The bombardment of carbon-doped clays appears to produce CO. This process occurs independently of any reduction of FeO involved in micrometoroid impacts [Tsay et al., 1971].

  4. Methionine metabolism: major pathways and enzymes involved and strategies for control and diversification of volatile sulphur compounds in cheese

    Microsoft Academic Search

    MARÍA DEL CARMEN MARTÍNEZ-CUESTA; CARMEN PELÁEZ; TERESA REQUENA

    2011-01-01

    For economical reasons and to accommodate current market trends, cheese manufacturers and product developers are increasingly interested in controlling cheese flavour formation and developing new flavours. Due to their low detection threshold and diversity, volatile sulphur compounds (VSCs) are of prime importance in the overall flavour of cheese and make a significant contribution to their typical flavours. Thus, the control

  5. On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization

    NASA Astrophysics Data System (ADS)

    Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

    2014-10-01

    New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5 s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones.

  6. On-site rapid detection of trace non-volatile inorganic explosives by stand-alone ion mobility spectrometry via acid-enhanced evaporization.

    PubMed

    Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

    2014-01-01

    New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5 s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones. PMID:25318960

  7. On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization

    PubMed Central

    Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

    2014-01-01

    New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5?s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones. PMID:25318960

  8. Product ion distributions for the reactions of NO+ with some physiologically significant volatile organosulfur and organoselenium compounds obtained using a selective reagent ionization time-of-flight mass spectrometer

    PubMed Central

    Mochalski, Pawe?; Unterkofler, Karl; Špan?l, Patrik; Smith, David; Amann, Anton

    2014-01-01

    RATIONALE The reactions of NO+ with volatile organic compounds (VOCs) in Selective Reagent Ionization Time-of-Flight Mass Spectrometry (SRI-TOF-MS) reactors are relatively poorly known, inhibiting their use for trace gas analysis. The rationale for this product ion distribution study was to identify the major product ions of the reactions of NO+ ions with 13 organosulfur compounds and 2 organoselenium compounds in an SRI-TOF-MS instrument and thus to prepare the way for their analysis in exhaled breath, in skin emanations and in the headspace of urine, blood and cell and bacterial cultures. METHODS Product ion distributions have been investigated by a SRI-TOF-MS instrument at an E/N in the drift tube reactor of 130 Td for both dry air and humid air (4.9% absolute humidity) used as the matrix gas. The investigated species were five monosulfides (dimethyl sulfide, ethyl methyl sulfide, methyl propyl sulfide, allyl methyl sulfide and methyl 5-methyl-2-furyl sulfide), dimethyl disulfide, dimethyl trisulfide, thiophene, 2-methylthiophene, 3-methylthiophene, methanethiol, allyl isothiocyanate, dimethyl sulfoxide, and two selenium compounds – dimethyl selenide and dimethyl diselenide. RESULTS Charge transfer was seen to be the dominant reaction mechanism in all reactions under study forming the M+ cations. For methanethiol and allyl isothiocyanate significant fractions were also observed of the stable adduct ions NO+M, formed by ion-molecule association, and [M–H]+ ions, formed by hydride ion transfer. Several other minor product channels are seen for most reactions indicating that the nascent excited intermediate (NOM)+* adduct ions partially fragment along other channels, most commonly by the elimination of neutral CH3, CH4 and/or C2H4 species that are probably bound to an NO molecule. Humidity had little effect on the product ion distributions. CONCLUSIONS The findings of this study are of particular importance for data interpretation in studies of volatile organosulfur and volatile organoselenium compounds employing SRI-TOF-MS in the NO+ mode. © 2014 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:24975248

  9. Development and validation of automatic HS-SPME with a gas chromatography-ion trap/mass spectrometry method for analysis of volatiles in wines.

    PubMed

    Paula Barros, Elisabete; Moreira, Nathalie; Elias Pereira, Giuliano; Leite, Selma Gomes Ferreira; Moraes Rezende, Claudia; Guedes de Pinho, Paula

    2012-11-15

    An automated headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-ion trap/mass spectrometry (GC-IT/MS) was developed in order to quantify a large number of volatile compounds in wines such as alcohols, ester, norisoprenoids and terpenes. The procedures were optimized for SPME fiber selection, pre-incubation temperature and time, extraction temperature and time, and salt addition. A central composite experimental design was used in the optimization of the extraction conditions. The volatile compounds showed optimal extraction using a DVB/CAR/PDMS fiber, incubation of 5 ml of wine with 2g NaCl at 45 °C during 5 min, and subsequent extraction of 30 min at the same temperature. The method allowed the identification of 64 volatile compounds. Afterwards, the method was validated successfully for the most significant compounds and was applied to study the volatile composition of different white wines. PMID:23158309

  10. Ultrafiltration behavior of major ions (Na, Ca, Mg, F, Cl, and SO4) in natural waters.

    PubMed

    Guo, L; Hunt, B J; Santschi, P H

    2001-04-01

    Aquatic colloids, including macromolecules and microparticles, with sizes ranging between 1 nm to 1 micron, play important roles in the mobility and bioavailability of heavy metals and other contaminants in natural waters. Cross-flow ultrafiltration has become one of the most commonly used techniques for isolating aquatic colloids. However, the ultrafiltration behavior of chemical species remains poorly understood. We report here the permeation behavior of major ions (Na, Ca, Mg, F, Cl, and SO4) in natural waters during ultrafiltration using an Amicon 1 kDa ultrafiltration membrane (S10N1). Water samples across a salinity gradient of 0-20@1000 were collected from the Trinity River and Galveston Bay. The permeation behavior of major ions was well predicted by a permeation model, resulting in a constant permeation coefficient for each ion. The value of the model-derived permeation coefficient (Pc) was 0.99 for Na, 0.97 for Cl, and 0.95 for F, respectively, in Trinity River waters. Values of Pc close to 1 indicate that retention of Na, Cl, and F by the 1 kDa membrane during ultrafiltration was indeed minimal (< 1-5%). In contrast, significant (14-36%) retention was observed for SO4, Ca, and Mg in Trinity River waters, with a Pc value of 0.64, 0.82, and 0.86 for SO4, Ca and Mg, respectively. However, these retained major ions can further permeate through the 1 kDa membrane during diafiltration with ultrapure water. The selective retention of major ions during ultrafiltration may have important implications for the measurement of chemical and physical speciation of trace elements when using cross-flow ultrafiltration membranes to separate colloidal species from natural waters. Our results also demonstrate that the percent retention of major ions during ultrafiltration decreases with increasing salinity or ionic strength. This retention is largely attributed to electrostatic repulsion by the negatively charged cartridge membrane. PMID:11317897

  11. Po and major ions in drainage water from soil treated with various types of fertilizers

    Microsoft Academic Search

    Fernando Jiménez; Raúl López; Rafael Pardo

    2007-01-01

    The levels of Po, nutrients (NH4 , NO3 , PO4 ) and major ions (Na, K, Mg, Ca, F, NO, Br, Cl, SO4 ) were determined, by means of lysimeter experiences, in drainage waters for agricultural soils untreated and treated with different types of fertilizers (animal manure, sewage sludge and NPK synthetic fertilizer) applied at several rates. Analytical determinations were

  12. DATA QUALIFICATION REPORT: MAJOR ION AND PH DATA FOR USE ON THE YUCCA MOUNTAIN PROJECT

    SciTech Connect

    C. WILSON; D.M. JENKINS; T. STEINBORN; R. WEMHEUER

    2000-08-23

    This data qualification report uses technical assessment and corroborating data methods according to Attachment 2 of AP-SIII.2Q, Rev. 0, ICN 2, ''Qualification of Unqualified Data and the Documentation of Rationale for Accepted Data'', to qualify major ion and pH data. This report was prepared in accordance with Data Qualification Plan TDP-NBS-GS-00003 1, Revision 2. Additional reports will be prepared to address isotopic and precipitation-related data. Most of the data considered in this report were acquired and developed by the U.S. Geological Survey (USGS). The data qualification team considers the sampling and analytical protocols employed by the USGS over the time period of data acquisition to be state-of-the-art. The sample collection methodologies have evolved with no significant change that could affect the quality of the data considered in this report into the currently used Hydrologic Procedures that support the Yucca Mountain Project-approved USGS Quality Assurance Program Plan. Consequently, for USGS data, the data collection methods, documentation, and results are reasonable and appropriate in view of standard practice at the time the data were collected. A small number of data sets were collected by organizations other than the USGS and were reviewed along with the other major ion and pH data using corroborating data methods. Hydrochemical studies reviewed in this qualification report indicate that the extent and quality of corroborating data are sufficient to support qualification of both USGS and non-USGS major ion and pH data for generalized hydrochemical studies. The corroborating data included other major ion and pH data, isotope data, and independent hydrological data. Additionally, the analytical adequacy of the major ion data was supported by a study of anion-cation charge balances. Charge balance errors for USGS and non-USGS data were under 10% and acceptable for all data. This qualification report addresses the specific major ion data sets selected to support the hydrochemical studies in Analysis/Model Report (AMR) S0040 and pH data used in AMRs U0100 and U0085. Based on a preponderance of evidence, these data are recommended to be qualified for inclusion in technical products in support of the Site Recommendation for generalized uses as described in this report.

  13. Predicting the Rejection of Major Seawater Ions by Spiral-Wound Nanofiltration Membranes.

    PubMed

    Fridman-Bishop, Noga; Nir, Oded; Lahav, Ori; Freger, Viatcheslav

    2015-07-21

    Seawater nanofiltration (SWNF) generates a softened permeate stream and a retentate stream in which the multivalent ions accumulate, offering opportunities for practical utilization of both streams. This study presents an approach to simulation of SWNF including all major seawater ions (Na(+), Cl(-), Ca(2+), Mg(2+), and SO4(2-)) based on the Nernst-Planck equation, and uses it for permeate and retentate streams composition prediction. The number of degrees of freedom in the system was reduced by assuming a very high ionic permeability for Na(+), which only weakly affected the other parameters in the system. Two alternatives were examined to analyze the importance of concentration dependence of ion permeabilities: The assumption of constant ion permeabilities resulted in a reasonable fit with experimental data. However, for the permeate composition the overall fit was significantly improved (P < 0.0001) when the permeabilities of Ca(2+) and Mg(2+) were allowed to depend on the ratio of their total concentration to Na(+). This type of dependence emphasizes the strong interaction of divalent ions with the membrane and its effect on the membrane fixed charge through screening or charge reversal. When this effect was included, model predictions closely matched the experimental results obtained, corroborating the phenomenological approach proposed in this study. PMID:26107401

  14. [Major ion chemistry of surface water in the Xilin River Basin and the possible controls].

    PubMed

    Tang, Xi-Wen; Wu, Jin-Kui

    2014-01-01

    Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in the steppe region in Inner Mongolia is urgently needed. Major ions are widely used to identify the hydrological processes in a river basin. Based on the analysis results of 239 river water samples collected in 13 sections along the Xilin River system during 2006 to 2008, combined with data from groundwater and precipitation samples collected in the same period and the meteorological and hydrological data in the Xilin River Basin, hydrochemical characteristics and the chemistry of major ions of the Xilin River water have been studied by means of Piper triangle plots and Gibbs diagrams. The results showed that: (1) the total dissolved solid (TDS) in river water mainly ranged between 136.7 mg x L(-1) and 376.5 mg x L(-1), and (2) it had an increasing trend along the river flow path. (3) The major cations and anions of river water were Ca2+ and HCO3-, respectively, and the chemical type of the river water varied from HCO3- -Ca2+ in the headwater area to HCO(3-)-Ca2+ Mg2+ in the lower part. (4) The variation in the concentration of major irons in surface water was not significant at the temporal scale. Usually, the concentration values of major irons were much higher in May than those in other months during the runoff season, while the values were a bit lower in 2007 than those in 2006 and 2008. Except for SO4(2-), the concentrations of other ions such as Ca2+, Na+, Mg2+, K+, Cl- and HCO3- showed a upward trend along the river flow path. Comparing major ion concentrations of the river water with those of local groundwater and precipitation, the concentration in river water was between those of precipitation and groundwater but was much closer to the concentration of groundwater. This indicated that the surface water was recharged by a mixture of precipitation and groundwater, and groundwater showed a larger impact. The Gibbs plot revealed that the chemical compositions of the river water were mainly affected by rock weathering in the drainage area. PMID:24720196

  15. The direct sampling ion trap mass spectrometer for the rapid analysis of volatile organic contaminants in groundwater samples

    SciTech Connect

    Eddy-Dilek, C.A.; Rossabi, J.; Keenan, M.A.

    1993-12-31

    Analytical results of volatile organic contaminant (VOC) concentrations in groundwater samples from A/M Area obtained using a direct sampling ion trap mass spectrometer (DSITMS) and a gas chromatograph (GC) with an electron capture detector (ECD) were comparable. Replicate water samples were collected at the Integrated Demonstration Site during four bi-weekly sampling periods and analyzed by both instruments. The calibration curves prepared for both the DSITMS and GC-ECD are essentially linear over the concentration range analyzed. The advantage of the DSITMS over the GC-ECD method is the rapid sample analysis time of the DSITMS. In order to validate the technology for use in the sample minimization efforts at SRS, duplicate groundwater samples from selected compliance wells were analyzed by DSITMS and GC-ECD. The DSITMS is appropriate to use for field screening water samples before offsite analysis. These analytical results will be compared with results from offsite labs contracted to perform contract lab program (CLP) analyses of regulatory samples when these analyses are available.

  16. Effects of hydrogen peroxide on the content of major volatile halogenated compounds in the red alga Asparagopsis taxiformis (Bonnemaisoniaceae)

    Microsoft Academic Search

    Leonardo Mata; Helena Gaspar; Fátima Justino; Rui Santos

    The genus Asparagopsis is a prolific source of halogenated metabolites. Due to its commercial applications, it has been intensively cultivated in\\u000a southern Portugal. In the present study, we assess if the internal levels of the major halogenated metabolites (bromoform\\u000a and dibromoacetic acid) in Asparagopsis taxiformis can be increased with hydrogen peroxide (H2O2) addition. Previous studies with red algae showed that

  17. Major ion chemistry of shallow groundwater of a fast growing city of central India.

    PubMed

    Marghade, Deepali; Malpe, D B; Zade, A B

    2012-04-01

    Nagpur City located in semiarid area of central India is a fast-growing industrial centre. In recent years, rapid development has created an increased demand for drinking water, which is increasingly being fulfilled by groundwater abstraction. The present study was undertaken to assess major ion chemistry of shallow groundwater to understand geochemical evolution of groundwater and water quality for promoting sustainable development and effective management of groundwater resources. A total of 47 water samples were collected from shallow aquifer of selected parts of the city and the water chemistry of various ions viz. Ca(2?+), Mg(2?+), Na(+), K(+), CO(3)(2-), HCO(3)(-), Cl(-), SO(4)(2-) and NO(3)(-) are carried out. The chemical relationships in Piper diagram identify Ca-HCO(3)-Cl and mixed Ca-Na-HCO(3)-Cl as most prevalent water types. Alkaline earth exceeds alkalis and weak acids exceed strong acids. Ionic ratios and Gibb's diagram suggest that silicate rock weathering and anthropogenic activities are the main processes that determine the ionic composition in the study area. The nitrate appeared as a major problem of safe drinking water in this region. We recorded highest nitrate concentration, i.e., 411 mg/l in one of the dug well. A comparison of groundwater quality in relation to drinking water quality standards revealed that about half of the shallow aquifer samples are not suitable for drinking. PMID:21617965

  18. Statistical models to predict the toxicity of major ions to Ceriodaphnia dubia, Daphnia magna and Pimephales promelas (fathead minnows)

    Microsoft Academic Search

    David R. Mount; David D. Gulley; J. Russell Hockett; Tyler D. Garrison; James M. Evans

    1997-01-01

    Toxicity of fresh waters with high total dissolved solids has been shown to be dependent on the specific ionic composition of the water. To provide a predictive tool to assess toxicity attributable to major ions, the authors tested the toxicity of over 2,900 ion solutions using the daphnids, Ceriodaphnia dubia and Daphnia magna, and fathead minnows (Pimephales promelas). Multiple logistic

  19. Mobilization of major inorganic ions during experimental diagenesis of characterized peats

    USGS Publications Warehouse

    Bailey, A.M.; Cohen, A.D.; Orem, W.H.; Blackson, J.H.

    2000-01-01

    Laboratory experiments were undertaken to study changes in concentrations of major inorganic ions during simulated burial of peats to about 1.5 km. Cladium, Rhizophora, and Cyrilla peats were first analyzed to determine cation distributions among fractions of the initial materials and minerals in residues from wet oxidation. Subsamples of the peats (80 g) were then subjected to increasing temperatures and pressures in steps of 5??C and 300 psi at 2-day intervals and produced solutions collected. After six steps, starting from 30??C and 300 psi, a final temperature of 60??C and a final pressure of 2100 psi were achieved. The system was then allowed to stand for an additional 2 weeks at 60??C and 2100 psi. Treatments resulted in highly altered organic solids resembling lignite and expelled solutions of systematically varying compositions. Solutions from each step were analyzed for Na+, Ca2+, Mg2+, total dissolved Si (Si(T)), Cl-, SO42-, and organic acids and anions (OAAs). Some data on total dissolved Al (Al(T)) were also collected. Mobilization of major ions from peats during these experiments is controlled by at least three processes: (1) loss of dissolved ions in original porewater expelled during compaction, (2) loss of adsorbed cations as adsorption sites are lost during modification of organic solids, and (3) increased dissolution of inorganic phases at later steps due to increased temperatures (Si(T)) and increased complexing by OAAs (Al(T)). In general, results provide insight into early post-burial inorganic changes occurring during maturation of terrestrial organic matter. (C) 2000 Elsevier Science B.V. All rights reserved.

  20. Influence of extraction methodologies on the analysis of five major volatile aromatic compounds of citronella grass (Cymbopogon nardus) and lemongrass (Cymbopogon citratus) grown in Thailand.

    PubMed

    Chanthai, Saksit; Prachakoll, Sujitra; Ruangviriyachai, Chalerm; Luthria, Devanand L

    2012-01-01

    This paper deals with the systematic comparison of extraction of major volatile aromatic compounds (VACs) of citronella grass and lemongrass by classical microhydrodistillation (MHD), as well as modern accelerated solvent extraction (ASE). Sixteen VACs were identified by GC/MS. GC-flame ionization detection was used for the quantification of five VACs (citronellal, citronellol, geraniol, citral, and eugenol) to compare the extraction efficiency of the two different methods. Linear range, LOD, and LOQ were calculated for the five VACs. Intraday and interday precisions for the analysis of VACs were determined for each sample. The extraction recovery, as calculated by a spiking experiment with known standards of VACs, by ASE and MHD ranged from 64.9 to 91.2% and 74.3 to 95.2%, respectively. The extraction efficiency of the VACs was compared for three solvents of varying polarities (hexane, dichloromethane, and methanol), seven different temperatures (ranging from 40 to 160 degrees C, with a gradual increment of 20 degrees C), five time periods (from 1 to 10 min), and three cycles (1, 2, and 3 repeated extractions). Optimum extraction yields of VACs were obtained when extractions were carried out for 7 min with dichloromethane and two extraction cycles at 120 degrees C. The results showed that the ASE technique is more efficient than MHD, as it results in improved yields and significant reduction in extraction time with automated extraction capabilities. PMID:22816268

  1. PCBs and OCPs on a east-to-west transect: the importance of major currents and net volatilization for PCBs in the Atlantic Ocean.

    PubMed

    Lohmann, Rainer; Klanova, Jana; Kukucka, Petr; Yonis, Shifra; Bollinger, Kevyn

    2012-10-01

    Air-water exchange gradients of selected polychlorinated biphenyl (PCB) congeners across a large section of the tropical Atlantic suggested net volatilization of PCBs to the atmosphere. Only for the higher chlorinated PCB 153 and hexachlorobenzene (HCB) were gradients near equilibrium detected. The use of passive samplers also enabled the detection of dichlorodiphenyltrichloroethane (DDT) and its transformation products across the tropical Atlantic, indicating net deposition. There were clear differences between the southern and northern hemisphere apparent in terms of atmospheric concentrations: Once the ship moved from the southern into the northern hemisphere air, concentrations of HCB and other organochlorine pesticides increased several-fold. For large swaths of the tropical Atlantic Ocean, neither PCB nor organochlorine pesticide dissolved concentrations varied much longitudinally, probably due to efficient mixing by ocean currents. In selected samples, dissolved concentrations reflected the influence of river plumes and major ocean currents far away from the continents. Dissolved concentrations of PCBs 28, 52, 101, 118, and HCB increased in the Amazon plume and the Gulf Stream. While the Amazon plume flushed only a few kg of PCBs and HCB, the Gulf Stream is potentially delivering tons of PCBs into the North Atlantic annually. PMID:22303957

  2. Ion Channel-Forming Alamethicin Is a Potent Elicitor of Volatile Biosynthesis and Tendril Coiling. Cross Talk between Jasmonate and Salicylate Signaling in Lima Bean1

    PubMed Central

    Engelberth, Jürgen; Koch, Thomas; Schüler, Göde; Bachmann, Nadine; Rechtenbach, Jana; Boland, Wilhelm

    2001-01-01

    Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces the biosynthesis of volatile compounds principally via the octadecanoid-signaling pathway (20-fold increase of jasmonic acid). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps in the biosynthetic pathway downstream of 12-oxophytodienoic acid and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by early octadecanoids. ALA also induces tendril coiling in various species like Pisum, Lathyrus, and Bryonia, but the response appears to be independent from octadecanoid biosynthesis, because inhibitors of lipoxygenase and phospholipase A2 do not prevent the coiling reaction. PMID:11154344

  3. Discussion of the formation of major positive and negative ions up to the 50 km level

    Microsoft Academic Search

    Volker A. Mohnen

    1971-01-01

    An attempt has been made to predict the nature of positive and negative ions up to a level of 50 km. Considerable progress has been made in recent years in the understanding of the mechanism of formation of small ions at ground levels and the altitude profile of ions presented here for the first time will rely on this previous

  4. Trace metal and major ion inputs into the Olentangy River from an urban storm sewer.

    PubMed

    Gardner, Christopher B; Carey, Anne E

    2004-10-15

    Trace metal clean techniques were used to sample and analyze the input of dissolved trace metals, major ions, and dissolved organic carbon (DOC) from a storm sewer along an urban highway in Columbus, OH. The outfall, draining a 3.6 ha sewershed with 100% impermeable surface area, discharges into the Olentangy River. Dissolved Pb (average concentration of 3 nM) and dissolved Zn (average concentration of 127 nM) were found to be much lower in concentration than reported in previous investigations of dissolved metals in urban stormwater runoff. Average concentrations of dissolved Cr (1 microM), Ni (0.087 microM), and Cu (0.33 microM) were similar to those reported in previous studies. The storm sewer is shown to be a significant source of V, Ni, and Zn to the river. The outfall is also a significant source of Na, NH4, Cl, and DOC. The storm sewer input is depleted in NO2 and NO3 as compared to the river, reflecting the highly agricultural land use of the watershed upstream of the sewershed. Input from the storm sewer is also depleted, as compared to the river, with respect to dissolved Mg, Sr, and U with probable sources in the limestone/shale bedrock and glacial till-derived soils in the watershed. PMID:15543732

  5. Assessment of seawater impact using major hydrochemical ions: a case study from Sadras, Tamilnadu, India.

    PubMed

    Mondal, N C; Singh, V S; Saxena, V K; Singh, V P

    2011-06-01

    The impact of seawater intrusion was investigated using major hydrogeochemical ions to evaluate the origin of salinity in Sadras watershed located between Buckingham Canal and Bay of Bengal in the southeastern coast of India. From empirical data collected twice during pre- and post-monsoon seasons, it was found that groundwater was slightly acidic to mildly alkaline, and more than 44% of groundwater samples had EC > 3,000 ?S/cm in both the seasons. Results of principle component analysis (PCA) showed that Na(?+?), Cl(?-?), Mg(2?+?), and SO[Formula: see text] concentrations had the highest loading factor and the samples affected by saline/seawater were separated from the cluster. Hydrochemical processes that accompany the saline/seawater were identified using ionic changes. It was observed during sampling periods that the mixing due to saline/seawater intrusion varied from 4.82-7.86%. Negative values of ionic change (e (change)) for Na(?+?) and K(?+?) decreased with the increasing fraction of seawater. Furthermore, salinity, sodium adsorption ratio, percentage of sodium Na (%), and exchangeable sodium percentage in well samples showed that groundwater was unsuitable for irrigation purposes. PMID:20711862

  6. Strontium isotope and major ion chemistry of the rainwaters from Guiyang, Guizhou Province, China.

    PubMed

    Han, Guilin; Liu, Cong-Qiang

    2006-07-01

    Twenty-two rainwater samples from Guiyang city, southwestern China, have been analyzed for their chemical compositions and 87Sr/86Sr ratios, with a main purpose to get a better understanding of the general features of rainwater in Guiyang city and their correspondences to human activities. The rainwaters studied are almost acidic (pH=4.53) and show big changes in major ion composition. Ca2+ and Mg2+ are the principal cations in the rainwaters and their mean values are 56.6 micromol/L (12.5-163.8 micromol/L) and 12.8 micromol/L (4.5-47.3 micromol/L ), respectively. The sum of Ca2+ and Mg2+ accounts for 78%-96% of the total cations in the studied rainwaters. Na+ was the least abundant of the major cations with a mean content of 4 micromol/L (0.9-7.8 micromol/L). SO4(2-) is the predominant anion, with a mean content of 94 micromol/L (33.5-279.4 micromol/L), coming next is NO(3-) with a mean content of 48 micromol/L (2.1-251.8 micromol/L). SO4(2-) and NO(3-) together account for 77%-99% of the total anions. Ca2+ and Mg2+ in the rainwater are most likely from dissolution of carbonate minerals in dust or aerosol, unlike K+ that shows more contribution of anthropogenic sources to the rainwater. Na+ does not vary in concentration with Cl-. Significant enrichment of Cl- relative to Na+ as compared with sea water indicates negligible contribution of marine source, which is supported by the evidence that the total rainwater samples show lower 87Sr/86Sr ratios (ranging from 0.707934 to 0.709080) than sea water. The rainwater samples are characterized by high contents of NO(3-), SO4(2-), and Cl- relative to Na+, as compared to the rainwater from other areas in the world, suggesting that the anions (NO(3-), SO4(2-), and Cl-) have mainly of anthropogenic sources. Sr isotope shows potential to trace sources of contaminants when combined with other chemical factors: covariation of 87Sr/86Sr ratio with Cl-/Na+ in the rainwater suggest presence of at least two anthropogenic sources for the rainwater samples studied. The coal-combustion industries are probably the major atmospheric contaminant sources in Guiyang city. PMID:16169575

  7. The climate signal recorded in the oxygen-isotope, accumulation and major-ion time series from the

    E-print Network

    Kurapov, Alexander

    The climate signal recorded in the oxygen-isotope, accumulation and major-ion time series from,YukonTerritory, Canada, are well suited for comparison of the glaciochemicalrecordwith instrumental time series temperature records with the Eclipse d18 O time series reveal a significant positive relationship between

  8. Differential modulatory actions of the volatile convulsant flurothyl and its anesthetic isomer at inhibitory ligand-gated ion channels

    Microsoft Academic Search

    Matthew D. Krasowski

    2000-01-01

    A challenge for theories of general anesthesia is the existence of compounds predicted to be anesthetics but which, instead, do not produce anesthesia and often elicit other behavioral effects such as convulsions. This study focused on flurothyl (bis[2,2,2-trifluoroethyl] ether), a potent volatile convulsant, and its anesthetic isomer, ‘iso-flurothyl’ (1,1,1,3,3,3-hexafluoro-2-methoxypropane). The effects of flurothyl and iso-flurothyl were studied using the whole-cell

  9. A Polymer-Rich Re-deposition Technique for Non-volatile Etching By-products in Reactive Ion Etching Systems

    NASA Astrophysics Data System (ADS)

    Limcharoen, A.; Pakpum, C.; Limsuwan, P.

    2013-07-01

    Re-deposition is a non-volatile etching by-product in reactive ion etching systems that is well known to cause dirt on etching work. In this study, we propose a novel etching method called the polymer-rich re-deposition technique, used particularly for improving the etched sidewall where the re-deposition is able to accumulate. This technique works by allowing the accumulated re-deposition on the etched sidewall to have a higher polymer species than the new compounds in the non-volatile etching by-product. The polymer-rich re-deposition is easy to remove along with the photo-resist mask residual at the photo-resist strip step using an isopropyl alcohol-based solution. The traditional, additional cleaning process step used to remove the re-deposition material is not required anymore, so this reduces the overall processing time. The technique is demonstrated on an Al2O3-TiC substrate by C4F8 plasma, and the EDX spectrum confirms that the polymer re-deposition has C and F atoms as the dominant atoms, suggesting that it is a C—F polymer re-deposition.

  10. MAJORITY ION HEATING BY NEUTRAL BEAM INJECTION AND CONFINEMENT OF FAST IONS IN THE MADISON SYMMETRIC TORUS REVERSED FIELD PINCH

    E-print Network

    Wisconsin at Madison, University of

    in a typical target discharge. At this beam energy and a background electron density of about 1x1019 m-3 pinch. The beam, consisting of two arc discharge plasma generators, an optimized ion optical system and an integrated neutralizer/ injector tank, op- erates at 25kV and up to 40A of neutrals for a 20 msec pulse

  11. Resection is a major repair pathway of heavy ion-induced DNA lesions

    NASA Astrophysics Data System (ADS)

    Durante, Marco; Averbeck, Nicole; Taucher-Scholz, Gisela

    Space radiation include densely ionizing heavy ions, which can produce clustered DNA damage with high frequency in human cells. Repair of these complex lesions is generally assumed to be more difficult than for simple double-strand breaks. We show here that human cells use break resection with increasing frequency after exposure to heavy ions. Resection can lead to misrepair of the DNA lesion, via microhomology mediated end-joining. Resection can therefore be responsible for the increased effectiveness of heavy ions in the induction of mutations and genetic late effects.

  12. Major-ion, nutrient, and trace-element concentrations in the Steamboat Creek basin, Oregon, 1996

    USGS Publications Warehouse

    Rinella, Frank A.

    1998-01-01

    In September 1996, a water-quality study was done by the U.S. Geological Survey, in coordination with the U.S. Forest Service, in headwater streams of Steamboat Creek, a tributary to the North Umpqua River Basin in southwestern Oregon. Field measurements were made in and surface-water and bottomsediment samples were collected from three tributaries of Steamboat Creek?Singe Creek, City Creek, and Horse Heaven Creek?and at one site in Steamboat Creek upstream from where the three tributaries flow into Steamboat Creek. Water samples collected in Singe Creek had larger concentrations of most major-ion constituents and smaller concentrations of most nutrient constituents than was observed in the other three creeks. City Creek, Horse Heaven Creek, and Steamboat Creek had primarily calcium bicarbonate water, whereas Singe Creek had primarily a calcium sulfate water; the calcium sulfate water detected in Singe Creek, along with the smallest observed alkalinity and pH values, suggests that Singe Creek may be receiving naturally occurring acidic water. Of the 18 trace elements analyzed in filtered water samples, only 6 were detected?aluminum, barium, cobalt, iron, manganese, and zinc. All six of the trace elements were detected in Singe Creek, at concentrations generally larger than those observed in the other three creeks. Of the detected trace elements, only iron and zinc have chronic toxicity criteria established by the U.S. Environmental Protection Agency (USEPA) for the protection of aquatic life; none exceeded the USEPA criterion. Bottom-sediment concentrations of antimony, arsenic, cadmium, copper, lead, mercury, zinc, and organic carbon were largest in City Creek. In City Creek and Horse Heaven Creek, concentrations for 11 constituents?antimony, arsenic, cadmium, copper, lead, manganese (Horse Heaven Creek only), mercury, selenium, silver, zinc, and organic carbon (City Creek only)?exceeded concentrations considered to be enriched in streams of the nearbyWillamette River Basin, whereas in Steamboat Creek only two trace elements ?antimony and nickel?exceeded Willamette River enriched concentrations. Bottom-sediment concentrations for six of these constituents in City Creek and Horse Heaven Creek?arsenic, cadmium, copper, lead, mercury, and zinc?also exceeded interim Canadian threshold effect level (TEL) concentrations established for the protection of aquatic life, whereas only four constituents between Singe Creek and Steamboat Creek?arsenic, chromium, copper (Singe Creek only), and nickel?exceeded the TEL concentrations.

  13. Effect of major ions on the toxicity of copper to Hyalella azteca and implications for the biotic ligand model

    Microsoft Academic Search

    Uwe Borgmann; Monica Nowierski; D. George Dixon

    2005-01-01

    The effect of major ions (Ca, Mg, Na, and K) and pH on Cu toxicity (LC50) to Hyalella azteca was determined in 1 week exposures. The simplest equation for describing Cu toxicity is a linear relationship between the total dissolved Cu LC50 and Ca and Na in water, ignoring pH. This equation would be useful in tier one of a

  14. The volatiles of desert truffle: Tirmania nivea.

    PubMed

    Omer, E A; Smith, D L; Wood, K V; el-Menshawi, B S

    1994-04-01

    The volatile constituents of Tirmania nivea (white desert truffle) have been analysed, using gas chromatography/mass spectrometric technique. 11 compounds have been identified in the ascocarp volatiles. The major components were found to be unsaturated fatty acids; whereas hexadecanoic [correction of haxadecanoic] acid represented 49% of the volatiles isolate. PMID:8052580

  15. Statistical models to predict the toxicity of major ions to Ceriodaphnia dubia, Daphnia magna and Pimephales promelas (fathead minnows)

    SciTech Connect

    Mount, D.R. [Environmental Protection Agency, Duluth, MN (United States); Gulley, D.D. [Univ. of Wyoming, Laramie, WY (United States); Hockett, J.R.; Garrison, T.D. [ENSR Consulting and Engineering, Fort Collins, CO (United States); Evans, J.M. [Gas Research Inst., Chicago, IL (United States)

    1997-10-01

    Toxicity of fresh waters with high total dissolved solids has been shown to be dependent on the specific ionic composition of the water. To provide a predictive tool to assess toxicity attributable to major ions, the authors tested the toxicity of over 2,900 ion solutions using the daphnids, Ceriodaphnia dubia and Daphnia magna, and fathead minnows (Pimephales promelas). Multiple logistic regression was used to relate ion composition to survival for each of the three test species. In general, relative ion toxicity was K{sup +} > HCO{sub 3}{sup {minus}} {approx} Mg{sup 2+} > Cl{sup {minus}} > SO{sub 4}{sup 2{minus}}; Na{sup +} and Ca{sup 2+} were not significant variables in the regressions, suggesting that the toxicity of Na{sup +} and Ca{sup 2+} salts was primarily attributable to the corresponding anion. For C. dubia and D. magna, toxicity of Cl{sup {minus}}, SO{sub 4}{sup 2{minus}}, and K{sup +} was reduced in solutions enriched with more than one cation. Final regression models showed a good quality of fit to the data (R{sup 2} = 0.767--0.861). Preliminary applications of these models to field-collected samples indicated a high degree of accuracy for the C. dubia model, while the D. magna and fathead minnow models tended to overpredict ion toxicity. Studies of oil and gas produced waters, irrigation drain waters, shale oil leachates, sediment pore waters, and industrial process waters have shown toxicity caused by elevated concentrations of common ions.

  16. Environmental isotopes and major ions for tracing leachate contamination from a municipal landfill in Metro Manila, Philippines.

    PubMed

    Castañeda, S S; Sucgang, R J; Almoneda, R V; Mendoza, N D S; David, C P C

    2012-08-01

    The surface water and groundwater sources in the vicinity of a major municipal landfill in Metro Manila, Philippines were investigated to determine contamination by landfill leachate. Tritium, stable isotopes of hydrogen and oxygen, and major ions in the leachate and freshwater within the landfill environment were determined. The leachate contained elevated tritium activities and high concentrations of sodium, chloride, potassium, and calcium. The concentrations of tritium and the leachate related ions in the affected surface water were significantly higher than the non-impacted water and correlated strongly with distance from the leachate source, following a negative exponential relationship, providing evidence of leachate transport along the affected surface water. Enrichment in deuterium was exhibited by leachate in the holding pond but not by the effluent leachate. The stable isotope signature of leachate is masked in the surface water due to dilution by stream water. Dilution similarly masked the effect of leachate in the shallow groundwater which was strongly influenced by precipitation. Evidence of leachate contamination in the deep groundwater was sporadic. In isolated cases, elevated tritium concentrations coincided with enrichment in deuterium. In the same case, leachate related ions, Na, Ca, Mg, and Cl, varied with rainfall but generally increased from 2003 to 2009. The effect on the groundwater of methane produced within the landfill was seen in the depletion in deuterium in groundwater in the drier months. PMID:22343499

  17. Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative

    SciTech Connect

    Reutter, D.J.; Hardy, D.R.

    1981-01-01

    Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

  18. TRPV3 and TRPV4 ion channels are not major contributors to mouse heat sensation

    Microsoft Academic Search

    Susan M Huang; Xiaoxin Li; YinYin Yu; Juan Wang; Michael J Caterina

    2011-01-01

    Background  The discovery of heat-sensitive Transient Receptor Potential Vanilloid (TRPV) ion channels provided a potential molecular\\u000a explanation for the perception of innocuous and noxious heat stimuli. TRPV1 has a significant role in acute heat nociception\\u000a and inflammatory heat hyperalgesia. Yet, substantial innocuous and noxious heat sensitivity remains in TRPV1 knockout animals.\\u000a Here we investigated the role of two related channels, TRPV3

  19. Export of carbon, nitrogen, and major ions from three tropical montane watersheds

    Microsoft Academic Search

    WILLIAM H. MCDOWELL; CLYDE E. ASBURY

    1994-01-01

    Annual exports of suspended sediment, dissolved and particulate C and N, dissolved N and P, and major cations and anions were measured in three montane tropical rain forest watersheds in Puerto Rico during 1983-1986. Organic C was primarily exported in the form of DOC, and DOC export (33-94 kg ha-' yr -I) was similar to values in larger tropical watersheds

  20. Modeling equilibrium and kinetic major ion chemistry with CO{sub 2} production/transport coupled to unsaturated water flow

    SciTech Connect

    Suarez, D.L.; Simunek, J. [Agricultural Research Service, Riverside, CA (United States). US Salinity Lab.

    1994-12-31

    Modeling the aqueous-phase composition in the unsaturated zone requires prediction of the gas-phase composition as well as water flow and chemical reactions. The authors discuss and demonstrate the use of two finite-element codes developed for variably saturated media at near earth-surface temperature. The SOILCO{sub 2} code was designed for predicting the CO{sub 2} concentration in the unsaturated zone, while the UNSATCHEM-2D code was designed for predicting major ion composition in the unsaturated zone. The SOILCO{sub 2} code couples CO{sub 2} production and transport with a variably saturated water flow model. The UNSATCHEM-2D code couples a variably saturated water flow model to CO{sub 2} production and transport, solute transport, and major-ion chemistry submodels. Since the solution chemistry in the unsaturated zone is significantly influenced by variations in water content, and in temperature and CO{sub 2} concentrations in the soil gas, all these variables are calculated by the models. The CO{sub 2} transport submodel includes both liquid and gas-phase transport.

  1. Application of ?(18)O, ?(13)CDIC, and major ions to evaluate micropollutant sources in the Bay of Vidy, Lake Geneva.

    PubMed

    Halder, Janine; Pralong, Charles; Bonvin, Florence; Lambiel, Frederic; Vennemann, Torsten W

    2014-10-30

    Waters were sampled monthly from a profile at the wastewater outlet and a reference point in the Bay of Vidy (Lake Geneva) for a year. The samples were analyzed for (18)O/(16)O of water, (13)C/(12)C of dissolved inorganic carbon (DIC), major ions, and selected micropollutant concentrations. ?(18)O values, combined with the major ion concentrations, allowed discharged waste and storm-drainage water to be traced within the water column. On the basis of ?(18)O values, mole fractions of wastewater (up to 45?%), storm-drainage (up to 16?%), and interflowing Rhône River water (up to 34?%) could be determined. The results suggest that the stormwater fractions do not influence micropollutant concentrations in a measurable way. In contrast, the Rhône River interflow coincides with elevated concentrations of Rhône River-derived micropollutants in some profiles. ?(13)C values of DIC suggest that an increase in micropollutant concentrations at the sediment-water interface could be related to remineralization processes or resuspension. PMID:25358053

  2. Studies of Sulfate Utilization by Algae. 5. Identification of Thiosulfate as a Major Acid-Volatile Product Formed by a Cell-Free Sulfate-Reducing System From Chlorella 1

    PubMed Central

    Levinthal, Mark; Schiff, Jerome A.

    1968-01-01

    Separation of the products formed from sulfate-35S by cell-free extracts of Chlorella pyrenoidosa (Emerson Strain 3) has permitted the identification of thiosulfate as a major product which yields acid-volatile radioactivity. The products formed, as separated by Dowex-1-nitrate chromatography, are qualitatively the same whether extracts at pH 7.0 (using TPNH as the reductant) or extracts at pH 9 [using 2,3-dimercaptopropan-1-ol, (BAL) as reductant] are employed. While thiosulfate can be separated without the addition of carrier, the inclusion of carrier improves the recovery. High concentrations of ATP which have been shown previously to inhibit the formation of acid-volatile radioactivity from radioactive sulfate, inhibit the formation of thiosulfate almost completely. Degradation of the thiosulfate formed at normal ATP concentrations reveals that most of the radioactivity is in the SO3-sulfur of the molecule suggesting that the SH-sulfur is derived from the enzyme extracts. If carrier sulfite is present during thiosulfate formation from sulfate-35S, radioactive sulfite is recovered at the expense of radioactive thiosulfate. Reconstruction experiments utilizing specifically-labeled thiosulfates indicate that radioactive sulfite formation is probably not the result of trapping a normal intermediate, but can be attributed to non-enzymatic exchange between labeled thiosulfate formed from sulfate and the non-radioactive sulfite added, suggesting that free sulfite is not an intermediate in thiosulfate formation from sulfate. PMID:16656806

  3. Primary emissions and secondary formation of volatile organic compounds from natural gas production in five major U.S. shale plays

    NASA Astrophysics Data System (ADS)

    Gilman, J.; Lerner, B. M.; Warneke, C.; Graus, M.; Lui, R.; Koss, A.; Yuan, B.; Murphy, S. M.; Alvarez, S. L.; Lefer, B. L.; Min, K. E.; Brown, S. S.; Roberts, J. M.; Osthoff, H. D.; Hatch, C. D.; Peischl, J.; Ryerson, T. B.; De Gouw, J. A.

    2014-12-01

    According to the U.S. Energy and Information Administration (EIA), domestic production of natural gas from shale formations is currently at the highest levels in U.S. history. Shale gas production may also result in the production of natural gas plant liquids (NGPLs) such as ethane and propane as well as natural gas condensate composed of a complex mixture of non-methane hydrocarbons containing more than ~5 carbon atoms (e.g., hexane, cyclohexane, and benzene). The amounts of natural gas liquids and condensate produced depends on the particular reservoir. The source signature of primary emissions of hydrocarbons to the atmosphere within each shale play will therefore depend on the composition of the raw natural gas as well as the industrial processes and equipment used to extract, separate, store, and transport the raw materials. Characterizing the primary emissions of VOCs from natural gas production is critical to assessing the local and regional atmospheric impacts such as the photochemical formation of ozone and secondary formation of organic aerosol. This study utilizes ground-based measurements of a full suite of volatile organic compounds (VOCs) in two western U.S. basins, the Uintah (2012-2014 winter measurements only) and Denver-Julesburg (winter 2011 and summer 2012), and airborne measurements over the Haynesville, Fayetteville, and Marcellus shale basins (summer 2013). By comparing the observed VOC to propane enhancement ratios, we show that each basin has a unique VOC source signature associated with oil and natural gas operations. Of the shale basins studied, the Uintah basin had the largest overall VOC to propane enhancement ratios while the Marcellus had the lowest. For the western basins, we will compare the composition of oxygenated VOCs produced from photochemical oxidation of VOC precursors and contrast the oxygenated VOC mixture to a "typical" summertime urban VOC mixture. The relative roles of alkanes, alkenes, aromatics, and cycloalkanes as precursors for C2-C6 aldehydes and ketones, and C3-C4 alkyl nitrates will be investigated.

  4. Ion sorption onto hydrous ferric oxides: Effect on major element fluid chemistry at Aspo, Sweden

    SciTech Connect

    Bruton, C.J.; Viani, B.E.

    1996-06-01

    The observed variability of fluid chemistry at the Aespoe Hard Rock Laboratory is not fully described by conservative fluid mixing models. Ion exchange may account for some of the observed discrepancies. It is also possible that variably charged solids such as oxyhydroxides of Fe can serve as sources and sinks of anions and cations through surface complexation. Surface complexation reactions on hydrous ferric oxides involve sorption of both cations and anions. Geochemical modeling of the surface chemistry of hydrous ferric oxides (HFOs) in equilibrium with shallow HBH02 and deep KA0483A waters shows that HFOs can serve as significant, pH-sensitive sources and sinks for cations and anions. Carbonate sorption is favored especially at below-neutral pH. A greater mass of carbonate is sorbed onto HFO surfaces than is contained in the fluid when 10 g goethite, used as a proxy for HFOs, is in contact with 1 kg H{sub 2}O. The masses of sorbent required to significantly impact fluid chemistry through sorption/desorption reactions seem to be reasonable when compared to the occurrences of HFOs at Aespoe. Thus, it is possible that small changes in fluid chemistry can cause significant releases of cations or anions from HFOs into the fluid phase or, alternately, result in uptake of aqueous species onto HFO surfaces. Simulations of the mixing of shallow HBH02 and native KA0483A waters in the presence of a fixed mass of goethite show that surface complexation does not cause the concentrations of Ca, Sr, and SO{sub 4} to deviate from those that are predicted using conservative mixing models. Results for HCO{sub 3} are more difficult to interpret and cannot be addressed adequately at this time.

  5. volatility. atthemoney

    E-print Network

    Lyuu, Yuh-Dauh

    volatility is lowest for at­the­money options. -- It becomes higher the further the option is in­ or out­of­the­money on the same underlying asset shows the Black­Scholes model cannot be literally true. c #2007 Prof. Yuh into the Black­Scholes formula and binomial tree algorithms? a Fama (1965); French (1980); French and Roll (1986

  6. Positive identification of the puberty-accelerating pheromone of the house mouse: the volatile ligands associating with the major urinary protein.

    PubMed Central

    Novotny, M V; Ma, W; Wiesler, D; Zídek, L

    1999-01-01

    Five structurally diverse small ligands, all binding to the major urinary protein (MUP) of the male house mouse, show individually puberty-accelerating pheromonal activity in the recipient females. A recombinant MUP (identical structurally to the natural protein) has shown no biological activity. While four of these ligands were previously implicated in oestrus synchronization (Whitten effect), the same chemosignals now appear responsible for both sexual maturation and cycling in adult females. PMID:10584338

  7. Quantitative Analysis of Isomeric Volatile Organic Compounds in a Northern Hardwood Forest by Proton Transfer Reaction Linear Ion Trap (PTR-LIT) Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Mielke, L. H.; Slade, J.; Alaghmand, M.; Galloway, M.; Kammrath, A.; Keutsch, F.; Bertman, S.; Carroll, M.; Stevens, P.; Dusanter, S.; Erickson, D.; McLuckey, S. A.; Shepson, P. B.

    2008-12-01

    Several low molecular weight, isomeric volatile organic compounds (VOCs) occur in the atmosphere in the low ppb to ppt range, including methyl vinyl ketone (MVK) and (MACR) from isoprene oxidation, and aerosol precursor monoterpenes and sesquiterpenes. Although proton transfer reaction mass spectrometry (PTR- MS) quantifies VOCs with low ppt limits of detection (LOD), it cannot differentiate isomers or isobaric molecules. A proton transfer reaction - linear ion trap (PTR-LIT) mass spectrometer was developed and utilized to quantify and distinguish isomers as well as test for interferants by allowing for MSn experiments while retaining LOD in the 100 ppt range for most compounds. The PTR-LIT was deployed at the PROPHET tower site at the University of Michigan Biological Station (UMBS) from July to mid-August 2008 to sample air above a mixed deciduous/coniferous forest canopy. The extended capabilities of the PTR-LIT were used to address local ozone formation from the oxidation of isoprene by monitoring speciated MVK and MACR. Good agreement existed between [MVK+MACR] in MS1 mode and [MVK] + [MACR] in MS2 mode. Possible interferences at common masses were directly addressed by comparing the MS2 spectra of atmospheric masses to those of standards. Aerosol formation and size distribution data were compared to VOC oxidation. In particular isoprene oxidation was monitored by using MVK, MACR, and glyoxal, a fifth generation oxidation product. Furthermore, total monoterpene concentration was monitored and oxidation rates were calculated. Finally, total sesquiterpenes were not observed above the limit of detection making them an unlikely source for either aerosol growth or the missing OH reactivity previously observed at UMBS.

  8. The Calcium Goes Meow: Effects of Ions and Glycosylation on Fel d 1, the Major Cat Allergen

    PubMed Central

    Pol-Fachin, Laércio; Verli, Hugo

    2015-01-01

    The major cat allergen, Fel d 1, is a structurally complex protein with two N-glycosylation sites that may be filled by different glycoforms. In addition, the protein contains three putative Ca2+ binding sites. Since the impact of these Fel d 1 structure modifications on the protein dynamics, physiology and pathology are not well established, the present work employed computational biology techniques to tackle these issues. While conformational effects brought upon by glycosylation were identified, potentially involved in cavity volume regulation, our results indicate that only the central Ca2+ ion remains coordinated to Fel d 1 in biological solutions, impairing its proposed role in modulating phospholipase A2 activity. As these results increase our understanding of Fel d 1 structural biology, they may offer new support for understanding its physiological role and impact into cat-promoted allergy. PMID:26134118

  9. Likelihood and objective Bayesian modeling of acidity and major ions in rainfall using a bivariate pseudo-Gamma distribution

    NASA Astrophysics Data System (ADS)

    Mohsin, Muhammad; Kazianka, Hannes; Pilz, Jürgen

    2013-04-01

    Modeling the acidity in rainfall at certain locations is a complex task because of different environmental conditions for different rainfall regimes and the large variability in the covariates involved. In this paper, concentration of acidity and major ions in the rainfall in UK is analyzed by assuming a bivariate pseudo-Gamma distribution. The model parameters are estimated by using the maximum likelihood method and the goodness of fit is checked. Furthermore, the non-informative Jeffreys prior for the distribution parameters is derived and a hybrid Gibbs sampling strategy is proposed to sample the corresponding posterior for conducting an objective Bayesian analysis. Finally, related quantities such as the deposition flux density are derived where the general pattern of the observed data appears to follow the fitted densities closely.

  10. The major surface protein complex of Treponema denticola depolarizes and induces ion channels in HeLa cell membranes.

    PubMed Central

    Mathers, D A; Leung, W K; Fenno, J C; Hong, Y; McBride, B C

    1996-01-01

    The oral spirochete Treponema denticola is closely associated with periodontal diseases in humans. The 53-kDa major surface protein (Msp) located in the outer membrane of T. denticola serovar a (ATCC 35405) has both pore-forming activity and adhesin activity. We have used standard patch clamp recording methods to study the effects of a partially purified outer membrane complex containing Msp on HeLa cells. The Msp complex was free of the chymotrypsin-like proteinase also found in the outer membrane of T. denticola. Msp bound to several HeLa cell proteins, including a 65-kDa surface protein and a 96-kDa cytoplasmic protein. The Msp complex depolarized and increased the conductance of the HeLa cell membrane in a manner which was not strongly selective for Na+, K+, Ca2+, and Cl- ions. Cell-attached patches of HeLa cell membrane exposed to Msp complex exhibited short-lived channels with a slope conductance of 0.4 nS in physiologically normal saline. These studies show that Msp binds both a putative epithelial cell surface receptor and cytoplasmic proteins and that the Msp complex can form large conductance ion channels in the cytoplasmic membrane of epithelial cells. These properties may contribute to the cytopathic effects of T. denticola on host epithelial cells. PMID:8757811

  11. Use of reconstituted waters to evaluate effects of elevated major ions associated with mountaintop coal mining on freshwater invertebrates.

    PubMed

    Kunz, James L; Conley, Justin M; Buchwalter, David B; Norberg-King, Teresa J; Kemble, Nile E; Wang, Ning; Ingersoll, Christopher G

    2013-12-01

    In previous laboratory chronic 7-d toxicity tests conducted with the cladoceran Ceriodaphnia dubia, surface waters collected from Appalachian sites impacted by coal mining have shown toxic effects associated with elevated total dissolved solids (TDS). The objective of the present study was to evaluate the effects of elevated major ions in chronic laboratory tests with C. dubia (7-d exposure), a unionid mussel (Lampsilis siliquoidea; 28-d exposure), an amphipod (Hyalella azteca; 28-d exposure), and a mayfly (Centroptilum triangulifer; 35-d exposure) in 3 reconstituted waters designed to be representative of 3 Appalachian sites impacted by coal mining. Two of the reconstituted waters had ionic compositions representative of alkaline mine drainage associated with mountaintop removal and valley fill-impacted streams (Winding Shoals and Boardtree, with elevated Mg, Ca, K, SO?, HCO?), and a third reconstituted water had an ionic composition representative of neutralized mine drainage (Upper Dempsey, with elevated Na, K, SO?, and HCO?). The waters with similar conductivities but, with different ionic compositions had different effects on the test organisms. The Winding Shoals and Boardtree reconstituted waters were consistently toxic to the mussel, the amphipod, and the mayfly. In contrast, the Upper Dempsey reconstituted water was toxic to the mussel, the amphipod, and the cladoceran but was not toxic to the mayfly. These results indicate that, although elevated TDS can be correlated with toxicity, the specific major ion composition of the water is important. Moreover, the choice of test organism is critical, particularly if a test species is to be used as a surrogate for a range of faunal groups. PMID:24243594

  12. The volatile compound BinBase mass spectral database

    PubMed Central

    2011-01-01

    Background Volatile compounds comprise diverse chemical groups with wide-ranging sources and functions. These compounds originate from major pathways of secondary metabolism in many organisms and play essential roles in chemical ecology in both plant and animal kingdoms. In past decades, sampling methods and instrumentation for the analysis of complex volatile mixtures have improved; however, design and implementation of database tools to process and store the complex datasets have lagged behind. Description The volatile compound BinBase (vocBinBase) is an automated peak annotation and database system developed for the analysis of GC-TOF-MS data derived from complex volatile mixtures. The vocBinBase DB is an extension of the previously reported metabolite BinBase software developed to track and identify derivatized metabolites. The BinBase algorithm uses deconvoluted spectra and peak metadata (retention index, unique ion, spectral similarity, peak signal-to-noise ratio, and peak purity) from the Leco ChromaTOF software, and annotates peaks using a multi-tiered filtering system with stringent thresholds. The vocBinBase algorithm assigns the identity of compounds existing in the database. Volatile compound assignments are supported by the Adams mass spectral-retention index library, which contains over 2,000 plant-derived volatile compounds. Novel molecules that are not found within vocBinBase are automatically added using strict mass spectral and experimental criteria. Users obtain fully annotated data sheets with quantitative information for all volatile compounds for studies that may consist of thousands of chromatograms. The vocBinBase database may also be queried across different studies, comprising currently 1,537 unique mass spectra generated from 1.7 million deconvoluted mass spectra of 3,435 samples (18 species). Mass spectra with retention indices and volatile profiles are available as free download under the CC-BY agreement (http://vocbinbase.fiehnlab.ucdavis.edu). Conclusions The BinBase database algorithms have been successfully modified to allow for tracking and identification of volatile compounds in complex mixtures. The database is capable of annotating large datasets (hundreds to thousands of samples) and is well-suited for between-study comparisons such as chemotaxonomy investigations. This novel volatile compound database tool is applicable to research fields spanning chemical ecology to human health. The BinBase source code is freely available at http://binbase.sourceforge.net/ under the LGPL 2.0 license agreement. PMID:21816034

  13. Predicting the toxicity of major ions in seawater to mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside minnow (Menidia beryllina)

    SciTech Connect

    Pillard, D.A.; DuFresne, D.L.; Caudle, D.D.; Tietge, J.E.; Evans, J.M.

    2000-01-01

    Although marine organisms are naturally adapted to salinities well above those of freshwater, elevated concentrations of specific ions have been shown to cause adverse effects on some saltwater species. Because some ions are also physiologically essential, a deficiency of these ions can also cause significant effects. To provide a predictive tool to assess toxicity associated with major ions, mysid shrimp (Mysidopsis bahia), sheepshead minnows (Cyprinodon variegatus), and inland silverside minnows (Menidia beryllina) were exposed to saline solutions containing calcium, magnesium, potassium, strontium, bicarbonate, borate, bromide, and sulfate at concentrations above and below what would be found in seawater. Solution salinity was maintained at approximately 31% by increasing or decreasing sodium and chloride concentrations. Logistic regression models were developed with both the ion molar concentrations and ion activity. Toxicity to all three species was observed when either a deficiency or an excess of potassium and calcium occurred. Significant mortality occurred in all species when exposed to excess concentrations of magnesium, bicarbonate, and borate. The response to the remaining ions varied with species. Sheepshead minnows were the most tolerant of both deficient and elevated levels of the different ions. Mysid shrimp and inland silverside minnows demonstrated similar sensitivities to several ions, but silverside minnow response was more variable. As a result, the logistic models that predict inland silverside minnow survival generally were less robust than for the other two species.

  14. Online volatile organic compound measurements using a newly developed proton-transfer ion-trap mass spectrometry instrument during New England Air Quality Study--Intercontinental Transport and Chemical Transformation 2004: performance, intercomparison, and compound identification.

    PubMed

    Warneke, Carsten; Kato, Shuji; De Gouw, Joost A; Goldan, Paul D; Kuster, William C; Shao, Min; Lovejoy, Edward R; Fall, Ray; Fehsenfeld, Fred C

    2005-07-15

    We have used a newly developed proton-transfer ion-trap mass spectrometry (PIT-MS) instrument for online trace gas analysis of volatile organic compounds (VOCs) during the 2004 New England Air Quality Study-Intercontinental Transport and Chemical Transformation study. The PIT-MS instrument uses proton-transfer reactions with H3O+ ions to ionize VOCs, similarto a PTR-MS (proton-transfer reaction mass spectrometry) instrument but uses an ion trap mass spectrometer to analyze the product ions. The advantages of an ion trap are the improved identification of VOCs and a near 100% duty cycle. During the experiment, the PIT-MS instrument had a detection limit between 0.05 and 0.3 pbbv (S/N = 3 (signal-to-noise ratio)) for 2-min integration time for most tested VOCs. PIT-MS was used for ambient air measurements onboard a research ship and agreed well with a gas chromatography mass spectrometer). The comparison included oxygenated VOCs, aromatic compounds, and others such as isoprene, monoterpenes, acetonitrile, and dimethyl sulfide. Automated collision-induced dissociation measurements were used to determine the contributions of acetone and propanal to the measured signal at 59 amu; both species are detected at this mass and are thus indistinguishable in conventional PTR-MS. PMID:16082971

  15. Major ion chemistry and dissolved inorganic carbon cycling in a human-disturbed mountainous river (the Luodingjiang River) of the Zhujiang (Pearl River), China

    Microsoft Academic Search

    Shurong Zhang; X. X. Lu; Huiguo Sun; Jingtai Han; David Laurence Higgitt

    2009-01-01

    Major ion chemistry and dissolved inorganic carbon system (DIC, mainly HCO3? and gaseous CO2) in the Luodingjiang River, a mountainous tributary of the Zhujiang (Pearl River), China, were examined based on a seasonal and spatial sampling scheme in 2005. The diverse distribution of lithology and anthropogenic impacts in the river basin provided the basic idea to assess the effects of

  16. Impacts of permafrost degradation on the riverine delivery of organic matter, inorganic nutrients, and major ions to the Arctic Ocean (Invited)

    Microsoft Academic Search

    K. E. Frey

    2009-01-01

    Over the next century, near-surface permafrost across the circumpolar Arctic is expected to degrade significantly, particularly for land areas south of 70°N. This is likely to cause widespread impacts on the riverine delivery of organic matter, inorganic nutrients, and major ions to the Arctic Ocean. These interacting processes can be highly complex and undoubtedly exhibit spatial and temporal variability associated

  17. Ions

    MedlinePLUS

    ... Ions with a positive charge are called cations. Ions with a negative charge are called anions. Many normal substances exist in the body as ions. Common examples include sodium, potassium, calcium, chloride, and ...

  18. The study of capacity fading processes of Li-ion batteries: major factors that play a role

    Microsoft Academic Search

    B Markovsky; A Rodkin; Y. S Cohen; O Palchik; E Levi; D Aurbach; H.-J Kim; M Schmidt

    2003-01-01

    In this work, we studied the impact of some factors on the behavior of practical electrodes of Li-ion batteries. These included elevated temperatures (45–80°C), prolonged storage of Li-ion cells, and additives in the electrolyte solution. The Li-ion battery systems studied included negative electrodes (anodes) comprising of mesocarbon microbeads (MCMB) and mesocarbon fibers (MCF), and LixCoO2 positive electrodes (cathodes) in an

  19. Principal Locations of Major-Ion, Trace-Element, Nitrate, and Escherichia coli Loading to Emigration Creek, Salt Lake County, Utah, October 2005

    USGS Publications Warehouse

    Kimball, Briant A.; Runkel, Robert L.; Walton-Day, Katherine

    2008-01-01

    Housing development and recreational activity in Emigration Canyon have increased substantially since 1980, perhaps causing an observed decrease in water quality of this northern Utah stream located near Salt Lake City. To identify reaches of the stream that contribute to water-quality degradation, a tracer-injection and synoptic-sampling study was done to quantify mass loading of major ions, trace elements, nitrate, and Escherichia coli (E. coli) to the stream. The resulting mass-loading profiles for major ions and trace elements indicate both geologic and anthropogenic inputs to the stream, principally from tributary and spring inflows to the stream at Brigham Fork, Burr Fork, Wagner Spring, Emigration Tunnel Spring, Blacksmith Hollow, and Killyon Canyon. The pattern of nitrate loading does not correspond to the major-ion and trace-element loading patterns. Nitrate levels in the stream did not exceed water-quality standards at the time of synoptic sampling. The majority of nitrate mass loading can be considered related to anthropogenic input, based on the field settings and trends in stable isotope ratios of nitrogen. The pattern of E. coli loading does not correspond to the major-ion, trace-element, or nitrate loading patterns. The majority of E. coli loading was related to anthropogenic sources based on field setting, but a considerable part of the loading also comes from possible animal sources in Killyon Canyon, in Perkins Flat, and in Rotary Park. In this late summer sampling, E. coli concentrations only exceeded water-quality standards in limited sections of the study reach. The mass-loading approach used in this study provides a means to design future studies and to evaluate the loading on a catchment scale.

  20. Identification of muscadine wine sulfur volatiles: pectinase versus skin-contact maceration.

    PubMed

    Gürbüz, Ozan; Rouseff, June; Talcott, Stephen T; Rouseff, Russell

    2013-01-23

    Muscadine grapes ( Vitis rotundifolia ) are widely grown in the southern United States, as the more common Vitis vinifera cannot be cultivated due to Pierce's disease. There is interest to determine if certain cultivars can be used for good-quality wine production. This study compared the effect of pectolytic enzyme pretreatment with conventional skin-contact fermentation on Muscadine (Noble, Vitis rotundifolia ) wine major volatiles, aroma active volatiles, and volatile sulfur compounds (VSCs). Volatile composition, aroma activity, and VSCs in the initial juice and wine samples after 3 years were determined by gas chromatography in combination with mass spectrometry (GC-MS), olfactory detection (GC-O), and pulsed flame photometric detection (GC-PFPD). Forty-three nonethanol MS volatiles were common to all samples. Total ion chromatogram (TIC) MS peak area increased 91% in the skin-contact wines from the initial juice but only 24% in the enzyme-treated wine. Thirty-one VSCs were detected. Twenty-four sulfur volatiles were identified by matching their retention characteristics on polar and nonpolar columns with those of standards or MS spectrum matches. Six of these (sulfur dioxide, 1-propanethiol, 3-mercapto-2-pentanone, 3-mercapto-2-butanone, 2,8-epithio-cis-p-menthane, and 1-p-menthene-8-thiol) were reported for the first time in muscadine wine. Five additional VSCs were tentatively identified by matching standardized retention values with literature values, and two remain unidentified. Total sulfur peak areas increased 400% in the skin-contact wine and 560% in the enzyme-treated wine compared to the initial juice. There were 42 aroma-active volatiles in the initial juice, 48 in the skin-contact wine, and 66 in the enzyme-treated wine. Eleven aroma-active volatiles in the skin-contact wine and 16 aroma volatiles in the enzyme-treated wine appear to be due to sulfur volatiles. Pectolytic enzyme-treated wines contained less total volatiles but more sulfur and aroma-active volatiles than the traditional skin-contact wine. PMID:23289372

  1. Geochemistry of the upper Han River basin, China. 2: Seasonal variations in major ion compositions and contribution of precipitation chemistry to the dissolved load.

    PubMed

    Li, Siyue; Zhang, Quanfa

    2009-10-30

    A total of 252 water samples were collected from 42 sites across the upper Han River basin during the time period from 2005-2006. Major ions (Cl(-), NO3(-), SO4(2-), HCO3(-), Na+, K+, Ca2+ and Mg2+), Si, water temperature, pH, EC and TDS were determined and consequently correlation matrix, analysis of variance, factor analysis and principal component analysis were performed in order to identify their seasonal variations and atmospheric inputs into river solutes. The results reveal that pH, EC, TDS, Cl(-), SO4(2-), HCO3(-), Ca2+ and Mg2+, K+ and Si generally tend to show the minimum compositions in months belong to the rainy season, while the dry season for NO3(-) and Na+. NO3(-), Mg2+ and Si have the maximum concentrations in months belong to the rainy season. By comparing the major ions relating to hydrological regime, NO3(-), contrary to other elements, has higher concentration in the rainy season. The overall water quality is non-polluted, while there are indications of enrichment of inorganic anions including NO3(-) causing water entrophication in the near future. The atmospheric inputs contribute to river solutes is limited with a mean inputs of approximate 1% in the basin. The understanding of the major ion dynamics would help water quality conservation in the basin for China's interbasin water transfer project. PMID:19523765

  2. A Test of a Major-ion Toxicity Model to Predict the Toxicity of Coal Bed Methane Product Waters to Aquatic Biota

    NASA Astrophysics Data System (ADS)

    Forbes, M. B.; Meyer, J. S.

    2003-12-01

    Coal bed methane (CBM) accounts for about 7.5% of the total natural gas production in the United States, and the Powder River Basin (PRB) in Montana and Wyoming has recently become a major production area. During CBM extraction, a coal seam is partially de-watered to relieve hydraulic pressure, thus causing methane gas to desorb. Some of this water (called product water) is discharged on the land surface and allowed to run into local drainages in the PRB. Due to the massive amounts of product water being discharged (rates up to 64,000 L/day per well), studies are needed to examine the potential effects on aquatic organisms. Additionally, models to predict such effects would be useful regulatory screening tools. To that end, we tested the ability of a multivariate logistic regression model of the toxicity of major inorganic ions (i.e., Na+, K+, Ca2+, Mg2+, Cl-, HCO3-, SO42-) to predict the acute toxicity of CBM-related waters to two aquatic invertebrates (Ceriodaphnia dubia and Daphnia magna) and fathead minnows (Pimephales promelas). First, we entered water chemistry data for several CBM product and receiving waters from the PRB into the major-ion model. Then we compared the model's predicted survival to the survival of the three species in toxicity tests we had previously conducted with those waters. For the majority of CBM product water and stream water samples in which CBM product water constituted the entire flow of the stream, the major-ion model consistently under-predicted survival by >50%. Therefore, from a regulatory standpoint, this model is conservative for detecting toxicity of CBM product waters (i.e., it over-predicts toxicity). Although the model appeared to be an excellent predictor of survival for receiving waters that contained no inputs from CBM processing (i.e., the difference between predicted and observed survival was <=10%), the majority of those cases were inconclusive tests of the model because the predicted and observed survival were either both >90% or both <10%. In such cases, it was not possible to test the accuracy of the regression coefficients in the major-ion model.

  3. Academic Majors Undergraduate Majors

    E-print Network

    Weston, Ken

    Department of Nutrition, Food and Exercise Sciences Aging/Cancer · Body Composition · Cardiovascular HealthAcademic Majors Undergraduate Majors Food & Nutrition Sciences Dietetics Exercise Science Athletic Training Masters Majors Nutrition & Food Sciences Exercise Physiology Sports Sciences Doctoral Majors

  4. Effect of ?-irradiation on the volatile compounds of medicinal herb, Paeoniae Radix

    NASA Astrophysics Data System (ADS)

    Shim, Sung-Lye; Hwang, In-Min; Ryu, Keun-Young; Jung, Min-Seok; Seo, Hye-young; Kim, Hee-Yeon; Song, Hyun-Pa; Kim, Jae-Hun; Lee, Ju-Woon; Byun, Myung-Woo; Kwon, Joong-Ho; Kim, Kyong-Su

    2009-07-01

    A study was carried out to find the effect of ?-irradiation on contents of volatile compounds from medicinal herb, Paeoniae Radix ( Paenia albiflora Pallas var. trichocarpa Bunge). The volatile compounds of control, 1, 3, 5 and 10 kGy irradiated samples were extracted by simultaneous steam distillation and extraction (SDE) method and analyzed by gas chromatograph-mass spectrometer. The major volatile compounds were paeonol, ( E)-carveol, ( E, E)-2,4-octadienal, methyl salicylate, myrtanol and eugenol acetate. Volatile compounds belonging to chemical classes of acids, alcohols, aldehydes, esters, hydrocarbons and miscellaneous were identified in all experimental samples. The types of volatile compounds in irradiated samples were similar to those of non-irradiated sample and the concentrations of these compounds differed between treatments. 1,3-Bis (1,1-dimethylethyl)-benzene was identified by using the selected ion monitoring (GC/MS-SIM) mode. The concentration of this compound increased with the increase of irradiation dose level. These results suggest that it could be used as the base data for the effect of ?-irradiation on medicinal herb.

  5. A selected ion flow tube study of the reactions of H3O+, NO+ and O2+ with some oxygenated biogenic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Amelynck, C.; Schoon, N.; Kuppens, T.; Bultinck, P.; Arijs, E.

    2005-12-01

    The rate constants and product ion distributions of the reactions of H3O+, NO+ and O2+ with 2-methyl-3-buten-2-ol, cis-3-hexen-1-ol, cis-3-hexenyl acetate, 1,8-cineole, 6-methyl-5-hepten-2-one, camphor and linalool have been determined at 150 Pa and 297 K using a selected ion flow tube (SIFT). All reactions were found to proceed at a rate close to the collision rate, calculated with the Su and Chesnavich model, using the polarizability and electric dipole moment of the compounds derived from B3LYP/aug-cc-pVDZ quantum chemical calculations. Additionally the product ion distributions of the reactions of these three ions with the terpenoid alcohols nerol and geraniol have been obtained.

  6. Current status of fluoride volatility method development

    SciTech Connect

    Uhlir, J.; Marecek, M.; Skarohlid, J. [UJV - Nuclear Research Institute, Research Centre Rez, CZ-250 68 Husinec - Rez 130 (Czech Republic)

    2013-07-01

    The Fluoride Volatility Method is based on a separation process, which comes out from the specific property of uranium, neptunium and plutonium to form volatile hexafluorides whereas most of fission products (mainly lanthanides) and higher transplutonium elements (americium, curium) present in irradiated fuel form nonvolatile tri-fluorides. Fluoride Volatility Method itself is based on direct fluorination of the spent fuel, but before the fluorination step, the removal of cladding material and subsequent transformation of the fuel into a powdered form with a suitable grain size have to be done. The fluorination is made with fluorine gas in a flame fluorination reactor, where the volatile fluorides (mostly UF{sub 6}) are separated from the non-volatile ones (trivalent minor actinides and majority of fission products). The subsequent operations necessary for partitioning of volatile fluorides are the condensation and evaporation of volatile fluorides, the thermal decomposition of PuF{sub 6} and the finally distillation and sorption used for the purification of uranium product. The Fluoride Volatility Method is considered to be a promising advanced pyrochemical reprocessing technology, which can mainly be used for the reprocessing of oxide spent fuels coming from future GEN IV fast reactors.

  7. Conference on Planetary Volatiles

    NASA Technical Reports Server (NTRS)

    Hrametz, K.; Kofler, L.

    1982-01-01

    Initial and present volatile inventories and distributions in the Earth, other planets, meteorites, and comets; observational evidence on the time history of volatile transfer among reservoirs; and volatiles in planetary bodies, their mechanisms of transport, and their relation to thermal, chemical, geological and biological evolution were addressed.

  8. Major ions, nutrients and primary productivity in volcanic neotropical streams draining rainforest and pasture catchments at Los Tuxtlas, Veracruz, Mexico

    Microsoft Academic Search

    Miriam G. Ramos-Escobedo; Gabriela Vázquez

    2001-01-01

    Six streams in the Los Tuxtlas region, a volcanic area in southeastern Mexico, were characterized chemically and biologically. Temperature, pH, conductivity, ions (Ca2+, Mg2+, Na+, K+, CaCO-3 and SO2-4), nutrients (NO-3, NH+4, total P and PO-34), and chlorophyll a from epilithon were measured every other month from September 1996 to July 1997. The streams studied had a consistent pattern of

  9. Establishing the occurrence of major and minor glucosinolates in Brassicaceae by LC-ESI-hybrid linear ion-trap and Fourier-transform ion cyclotron resonance mass spectrometry.

    PubMed

    Lelario, Filomena; Bianco, Giuliana; Bufo, Sabino A; Cataldi, Tommaso R I

    2012-01-01

    Glucosinolates (GLSs) are sulfur-rich plant secondary metabolites which occur in a variety of cruciferous vegetables and among various classes of them, genus Brassica exhibits a rich family of these phytochemicals at high, medium and low abundances. Liquid chromatography (LC) with electrospray ionization in negative ion mode (ESI-) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS) was employed for the selective and sensitive determination of intact GLSs in crude sample extracts of broccoli (Brassica oleracea L. Var. italica), cauliflower (B. oleracea L. Var. Botrytis) and rocket salad (Eruca sativa L.) with a wide range of contents. When LTQ and FTICR mass analyzers are compared, the magnitude of the limit of detection was ca. 5/6-fold lower with the FTICR MS. In addition, the separation and detection by LC-ESI-FTICR MS provides a highly selective assay platform for unambiguous identification of GLSs, which can be extended to lower abundance (minor) GLSs without significant interferences of other compounds in the sample extracts. The analysis of Brassicaceae species emphasized the presence of eight minor GLSs, viz. 1-methylpropyl-GLS, 2-methylpropyl-GLS, 2-methylbutyl-GLS, 3-methylbutyl-GLS, n-pentyl-GLS, 3-methylpentyl-GLS, 4-methylpentyl-GLS and n-hexyl-GLS. The occurrence of these GLSs belonging to the saturated aliphatic side chain families C(4), C(5) and C(6), presumably formed by chain elongation of leucine, homoleucine and dihomoleucine as primary amino acid precursors, is described. Based on their retention behavior and tandem MS spectra, all these minor compounds occurring in plant extracts of B. oleracea L. Var. italica, B. oleracea L. Var. Botrytis and E. sativa L. were tentatively identified. PMID:22030302

  10. Some unusual minor volatile components of tomato.

    PubMed

    Buttery, Ron G; Takeoka, Gary R

    2004-10-01

    The identities and possible origins of three minor unusual volatile components of tomato are discussed. These are pentyl nitrate, the first identification of a volatile alkyl nitrate in a fresh vegetable or fruit; 5-ethyl-2(5H)-furanone, which, besides its presence in tomato, was found to be a major autoxidation product of pure (Z)-3-hexenal; and 5-ethylcyclopentene-1-carbaldehyde, a likely unusual linolenic acid oxidation product. PMID:15453697

  11. Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: Laboratory studies and reactive transport modeling

    NASA Astrophysics Data System (ADS)

    Holden, A. A.; Haque, S. E.; Mayer, K. U.; Ulrich, A. C.

    2013-08-01

    Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840 × 106 m3 and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~ 375 mg L- 1) and Na (~ 575 mg L- 1) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides — in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present results suggest that in addition to the commonly cited naphthenic acids, remediation of OSPW-impacted groundwater will need to address high concentrations of major ions contributing to salinization.

  12. A BENCH SCALE STUDY ON BIODEGRADATION AND VOLATILIZATION OF ETHYLBENZOATE IN AQUIFERS. (R825549C039)

    EPA Science Inventory

    Experiments were conducted to investigate the fate of ethylbenzoate and soil microorganisms in shallow aquifers. Biodegradation and volatilization have been identified as the major mechanisms in attenuating ethylbenzoate in contaminated soils. The rate of volatilization was ex...

  13. Characterization of major-ion chemistry and nutrients in headwater streams along the Appalachian National Scenic Trail and within adjacent watersheds, Maine to Georgia

    USGS Publications Warehouse

    Argue, Denise M.; Pope, Jason P.; Dieffenbach, Fred

    2012-01-01

    An inventory of water-quality data on field parameters, major ions, and nutrients provided a summary of water quality in headwater (first- and second-order) streams within watersheds along the Appalachian National Scenic Trail (Appalachian Trail). Data from 1,817 sampling sites in 831 catchments were used for the water-quality summary. Catchment delineations from NHDPlus were used as the fundamental geographic units for this project. Criteria used to evaluate sampling sites for inclusion were based on selected physical attributes of the catchments adjacent to the Appalachian Trail, including stream elevation, percentage of developed land cover, and percentage of agricultural land cover. The headwater streams of the Appalachian Trail are generally dilute waters, with low pH, low acid neutralizing capacity (ANC), and low concentrations of nutrients. The median pH value was slightly acidic at 6.7; the median specific conductance value was 23.6 microsiemens per centimeter, and the median ANC value was 98.7 milliequivalents per liter (?eq/L). Median concentrations of cations (calcium, magnesium, sodium, and potassium) were each less than 1.5 milligrams per liter (mg/L), and median concentrations of anions (bicarbonate, chloride, fluoride, sulfate, and nitrate) were less than 10 mg/L. Differences in water-quality constituent levels along the Appalachian Trail may be related to elevation, atmospheric deposition, geology, and land cover. Spatial variations were summarized by ecological sections (ecosections) developed by the U.S. Forest Service. Specific conductance, pH, ANC, and concentrations of major ions (calcium, chloride, magnesium, sodium, and sulfate) were all negatively correlated with elevation. The highest elevation ecosections (White Mountains, Blue Ridge Mountains, and Allegheny Mountains) had the lowest pH, ANC, and concentrations of major ions. The lowest elevation ecosections (Lower New England and Hudson Valley) generally had the highest pH, ANC, and concentrations of major ions. The geology in discrete portions of these two ecosections was classified as containing carbonate minerals which has likely influenced the chemical character of the streamwater. Specific conductance, pH, ANC, and concentrations of major ions (calcium, chloride, magnesium, sodium, and sulfate) were all positively correlated with percentages of developed and agricultural land uses at the lower elevations of the central region of the Appalachian Trail (including the Green-Taconic-Berkshire Mountains, Lower New England, Hudson Valley, and Northern Ridge and Valley ecosections). The distinctly different chemical character of the streams in the central sections of the Appalachian Trail is likely related to the lower elevations, the presence of carbonate minerals in the geology, higher percentages of developed and agricultural land uses, and possibly the higher inputs of sulfate and nitrate from atmospheric deposition. Acid deposition of sulfate and nitrate are important influences on the acid-base chemistry of the surface waters of the Appalachian Trail. Atmospheric deposition estimates are consistently high (more than 18 kilograms per hectare (kg/ha) for sulfate, and more than 16 kg/ha for nitrate) at both the highest and lowest elevations. However, the lowest elevation (Green-Taconic-Berkshire Mountains, Lower New England, Hudson Valley, Northern Glaciated Allegheny Plateau, and Northern Ridge and Valley ecosections) included the largest spatial area of sustained high estimates of atmospheric deposition. Calcium-bicarbonate was the most frequently calculated water type in the Lower New England and Hudson Valley ecosections. In the northern and southern sections of the Appalachian Trail mix-cation water types were most prevalent and sulfate was the predominate anion. The predominance of the sulfate anion in the surface waters of the northern and southern ecosections likely reflects the influence of sulfate deposition. Although the central portion of the Appalachian Trail has the largest spatial area of high atmospheric acid deposition, the

  14. [Composition characteristics and source analysis of major ions in four small lake-watersheds on the Tibetan Plateau, China].

    PubMed

    Li, He; Li, Jun; Liu, Xiao-Long; Yang, Xi; Zhang, Wei; Wang, Jie; Niu, Ying-Quan

    2015-02-01

    To investigate the ionic compositions of small lake-watersheds on the Tibetan Plateau, water samples from the brackish lakes (Pung Co (lake), Angrenjin Co and Dajia Co), the freshwater lake (Daggyaima Co), their inflowing rivers and the hot spring (Dagejia Geothermal Field), were collected during July-August 2013. The results showed that the major anions and cations of the brackish lakes were HCO3-, SO4(2-) and Na+, respectively, and the hydrochemical types were HCO3-SO4-Na and HCO3-Na. The major anions and cations of the inflowing rivers and the freshwater lake were HCO3-, SO4(2-) and Ca2+, Mg2+, respectively, and the hydrochemical types were HCO3-Ca, HCO3-Ca-Mg, HCO3-Mg-Ca, HCO3-SO4-Ca and SO4-HCO3- Ca. The major anions and cations of the hot spring were HCO3- and Na+, respectively, and the hydrochemical type was HCO3-Na. Water chemistry in the brackish lakes was primarily dominated by evaporation-crystallization processes, while the inflowing rivers and the freshwater lake were mainly influenced by carbonate weathering, and the hot spring was mainly controlled by hot water-granite interaction. Ca2+ was preferentially removed over Mg2+ from the water when carbonate minerals precipitation occured, which resulted in the high Mg2+/Ca2+ molar ratios of the brackish lakes. In the contribution of cation compositions, the largest contribution was carbonate weathering (54% - 79%), followed by silicate weathering (13% -29%) and evaperite dissolution (4% -23%), and the smallest was atmospheric input (3% - 7%). PMID:26031067

  15. Major Ions Fluxes and DOC in Rainfall and Throughfall at the Tapajos National Forest - Belterra, Para, Brazil

    NASA Astrophysics Data System (ADS)

    Oliveira, R. C.; Keller, M.; Crill, P.; de Mello, W.; Dias, J.; Oliveira, K.; Souza Neto, E.; Albuquerque, S.; Dias, J.; Pereira, C.

    2004-12-01

    The Tapajós National Forest -(FLONA Tapajós), an area of 600,000 ha of protected forest, is located 50km south Santarem (Pará, Brasil). The FLONA receives approximately 2000 mm.y-1 of rainfall and the forest is evergreen. The tropical forest nutrient cycle depends upon inputs from the atmosphere and from rock weathering. Internally, throughfall and stemflow transfer nutrients from the vegetation to the ground. We collected rainfall and throughfall from [starting date] through [ending date]. Concentrations of the ions Cl-, NO3-, PO4-3, SO4-2, Na+, NH4+, K+, Mg+2 and Ca+2 were analyzed using a Dionex DX-120 ion chromatograph. Total carbon and dissolved organic carbon were analyzed by a Shimadzu TOC V - CSN. Ionic fluxes were calculated from volume-weighted concentrations. The fluxes in precipitation followed the sequence: NH4+ (7.1 kg.ha-1.y-1) > Ca+2 (6.31 kg.ha-1.y-1) > Na+ (6.11 kg.ha-1.y-1) > K+ (4.41 kg.ha-1.y-1) > Cl- (3.61 kg.ha-1.y-1) > SO4-2 (3.11 kg.ha-1.y-1) > NO3- (1.31 kg.ha-1.y-1) > PO4-3 (1.11 kg.ha-1.y-1) > Mg+2 (1.01 kg.ha-1.y-1). In the throughfall, the fluxes were in the sequence: NO3- (31.8 kg.ha-1.y-1) > K+ (27.6 kg.ha-1.y-1) > NH4+ (25.5 kg.ha-1.y-1) > Na+ (17.4 kg.ha-1.y-1) > SO4-2 (15.6 kg.ha-1.y-1) > Cl- (14.5 kg.ha-1.y-1) > Ca+2 (12.7 kg.ha-1.y-1) > Mg+2 (11.1 kg.ha-1.y-1) > PO4-3 (10.8 kg.ha-1.y-1). The seasonality of cation and anion inputs suggests that intensive fertilized grain agricultural activity upwind of the site is contributing a substantial nutrient input to the forest. The fluxes of the total organic carbon for April 2003, May 2003 and February 2004 reached amounts of the 23, 18 and 34 kg.ha-1.y-1, respectively.

  16. Lunar apatite with terrestrial volatile abundances.

    PubMed

    Boyce, Jeremy W; Liu, Yang; Rossman, George R; Guan, Yunbin; Eiler, John M; Stolper, Edward M; Taylor, Lawrence A

    2010-07-22

    The Moon is thought to be depleted relative to the Earth in volatile elements such as H, Cl and the alkalis. Nevertheless, evidence for lunar explosive volcanism has been used to infer that some lunar magmas exsolved a CO-rich and CO(2)-rich vapour phase before or during eruption. Although there is also evidence for other volatile species on glass spherules, until recently there had been no unambiguous reports of indigenous H in lunar rocks. Here we report quantitative ion microprobe measurements of late-stage apatite from lunar basalt 14053 that document concentrations of H, Cl and S that are indistinguishable from apatites in common terrestrial igneous rocks. These volatile contents could reflect post-magmatic metamorphic volatile addition or growth from a late-stage, interstitial, sulphide-saturated melt that contained approximately 1,600 parts per million H(2)O and approximately 3,500 parts per million Cl. Both metamorphic and igneous models of apatite formation suggest a volatile inventory for at least some lunar materials that is similar to comparable terrestrial materials. One possible implication is that portions of the lunar mantle or crust are more volatile-rich than previously thought. PMID:20651686

  17. Iodine volatility. [PWR; BWR

    SciTech Connect

    Beahm, E.C.; Shockley, W.E.

    1984-01-01

    The ultimate aim of this program is to couple experimental aqueous iodine volatilities to a fission product release model. Iodine partition coefficients, for inorganic iodine, have been measured during hydrolysis and radiolysis. The hydrolysis experiments have illustrated the importance of reaction time on iodine volatility. However, radiolysis effects can override hydrolysis in determining iodine volatility. In addition, silver metal in radiolysis samples can react to form silver iodide accompanied by a decrease in iodine volatility. Experimental data are now being coupled to an iodine transport and release model that was developed in the Federal Republic of Germany.

  18. Nanosims Imaging of Volatile Elements (H, C, F and S) in Shergottites

    NASA Technical Reports Server (NTRS)

    Wang, J.; Usui, T.; Alexander, C. M. O'D.; Simon, J. I.; Jones, J. H.

    2012-01-01

    Volatiles, especially water, play a critical role in the evolution of Mars and other planetary bodies. Though the detection limit and spatial resolution in measuring volatiles in different phases of Martian meteorites have been greatly improved using ion microprobes (SIMS), it remains a challenge to accurately determine volatile concentrations due to contamination by terrestrial volatiles. Most Martian meteorites experienced cracking and shattering from the high-pressure shock either on the Martian surface and/or when coming to Earth. Martian meteorites generally contain volatiles in cracks even after careful sample preparation for SIMS analysis. We used the Cameca NanoSIMS 50L at Carnegie Institution of Washington to image volatile (H, C, F and S) distributions in two shergottite meteorites, LAR 06319 (L2) and Y-980456 (Y3). The mapping of volatiles in these meteorites greatly assisted us in understanding the distribution of volatile contamination and in improving future volatile measurement methods

  19. Integrated Chemical and Microorganism Monitoring of Air Using Gas Chromatography/Ion Mobility Spectometry: Toward an Expanded-Use Volatile Organic Analyzer (VOA)

    NASA Technical Reports Server (NTRS)

    Eiceman, G. A.

    1999-01-01

    The work described in this research program originated with the choice by NASA of an ion mobility spectrometer for air quality monitoring on-board the international spacestation. Though the gas chromatograph-ion mobility spectrometer analyzer known as VOA met or exceeded expectations, limitations in the basic understanding of response and the utilization of foundational principles into usable technology was considered unacceptable. In this research program, a comprehensive model for the origins of mobility spectra was proposed, tested and verified. The principles considered responsible for the appearance of mobility spectra have now been elucidated through this project. This understanding has been applied in automated identification of mobility spectra using neural networks and routine procedures for this now exist. Finally, the limitation on linear range has been shown to be a technical limitation and not a fundamental limitation so that a hardware component was crafted to extend the linear range of a mobility spectrometer by 10X. This project has led to one Ph.D. dissertation and one MS thesis. In addition, over ten public presentations at professional meetings and six journal publications have resulted from this program of research. The findings are so plentiful that total analysis of the findings may require four to six years or more. The findings confirm that the decision to use VOA was sound and that the chemical and physical principles of mobility spectrometry are both understandable and predictable.

  20. Volatile composition and aroma activity of guava puree before and after thermal and dense phase carbon dioxide treatments.

    PubMed

    Plaza, Maria Lourdes; Marshall, Maurice R; Rouseff, Russell Lee

    2015-02-01

    Volatiles from initially frozen, dense phase carbon dioxide (DPCD)- and thermally treated guava purees were isolated by solid phase microextraction (SPME), chromatographically separated and identified using a combination of gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), and GC-pulsed flame photometric detector (GC-PFPD, sulfur mode). Fifty-eight volatiles were identified using GC-MS consisting of: 6 aldehydes, 2 acids, 15 alcohols, 6 ketones, 21 esters, and 8 terpenes. Eleven volatiles were newly identified in guava puree. Hexanal was the most abundant volatile in all 3 types of guava puree. Ten sulfur compounds were identified using GC-PFPD of which 3 possessed aroma activity and 3 were not previously reported in guava puree. Both treatments profoundly reduced total sulfur peak areas and produced different peak patterns compared to control. Thermal treatment reduced total sulfur peak area 47.9% compared to a loss of 34.7% with DPCD treatment. Twenty-six volatiles possessed aroma activity. (Z)-3-Hexenyl hexanoate was the major contributor to the aroma of the freshly thawed and DPCD-treated guava puree. DPCD treatment reduced total MS ion chromatogram (MS TIC) peak area 35% but produced a GC-O aroma profile very similar to control. Whereas thermal treatment reduced total TIC peak area only 8.7% compared to control but produced a 35% loss in total GC-O peak intensities. PMID:25588413

  1. Major ion chemistry and hydrochemical studies of groundwater of parts of Palar river basin, Tamil Nadu, India.

    PubMed

    Dar, Mithas Ahmad; Sankar, K; Dar, Imran Ahmad

    2011-05-01

    Groundwater is almost globally important for human consumption as well as for the support of habitat and for maintaining the quality of base flow to rivers, while its quality assessment is essential to ensure sustainable safe use of the resources for drinking, agricultural, and industrial purposes. In the current study, 50 groundwater samples were collected from parts of Palar river basin to assess water quality and investigate hydrochemical nature by analyzing the major cations (Ca, Mg, Na, K) and anions (HCO(3), Cl, F,SO(4), NO(3), PO(4),CO(3), HCO(3), and F) besides some physical and chemical parameters (pH, electrical conductivity, alkalinity, and total hardness). Also, geographic information system-based groundwater quality mapping in the form of visually communicating contour maps was developed using ArcGIS-9.2 to delineate spatial variation in physicochemical characteristics of groundwater samples. Wilcox classification and US Salinity Laboratory hazard diagram suggests that 52% of the groundwater fall in the field of C2-S1, indicating water of medium salinity and low sodium, which can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. Remaining 48% is falling under C1-SI, indicating water of low salinity and low sodium. PMID:20886289

  2. Bond Illiquidity and Excess Volatility

    E-print Network

    Bao, Jack

    We find that the empirical volatilities of corporate bond and CDS returns are higher than implied by equity return volatilities and the Merton model. This excess volatility may arise because structural models inadequately ...

  3. Volatility and commodity price dynamics

    E-print Network

    Pindyck, Robert S.

    2001-01-01

    Commodity prices tend to be volatile, and volatility itself varies over time. changes in volatility can affect market variables by directly affecting the marginal value of storage, and by affecting a component of the total ...

  4. Emerging equity market volatility

    Microsoft Academic Search

    Geert Bekaert; Campbell R. Harvey

    1997-01-01

    Understanding volatility in emerging capital markets is important for determining the cost of capital and for evaluating direct investment and asset allocation decisions. We provide an approach that allows the relative importance of world and local information to change through time in both the expected returns and conditional variance processes. Our time-series and cross-sectional models analyze the reasons that volatility

  5. MEASUREMENT OF VOLATILE SULFUR COMPOUNDS ASSOCIATED WITH ANIMAL FEEDING OPERATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile sulfur compounds (VSC) are a major class of chemicals associated with odor from animal feeding operations. Identifying and quantifying VSC in air is challenging due to their volatility, reactivity, and low concentrations. In this study, a canister based method is presented that allowed fo...

  6. Phase partitioning and volatility of secondary organic aerosol components formed from ?-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; Kroll, J. H.; Worsnop, D.; Thornton, J. A.

    2015-02-01

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25-50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.

  7. An exploratory comparative study of volatile compounds in exhaled breath and emitted by skin using selected ion flow tube mass spectrometry.

    PubMed

    Turner, Claire; Parekh, Bhavin; Walton, Christopher; Spanel, Patrik; Smith, David; Evans, Mark

    2008-01-01

    Selected ion flow tube mass spectrometry (SIFT-MS) has been used to carry out a pilot parallel study on five volunteers to determine changes occurring in several trace compounds present in exhaled breath and emitted from skin into a collection bag surrounding part of the arm, before and after ingesting 75 g of glucose in the fasting state. SIFT-MS enabled real-time quantification of ammonia, methanol, ethanol, propanol, formaldehyde, acetaldehyde, isoprene and acetone. Following glucose ingestion, blood glucose and trace compound levels were measured every 30 min for 2 h. All the above compounds, except formaldehyde, were detected at the expected levels in exhaled breath of all volunteers; all the above compounds, except isoprene, were detected in the collection bag. Ammonia, methanol and ethanol were present at lower levels in the bag than in the breath. The aldehydes were present at higher levels in the bag than in breath. The blood glucose increased to a peak about 1 h post-ingestion, but this change was not obviously correlated with temporal changes in any of the compounds in breath or emitted by skin, except for acetone. The decrease in breath acetone was closely mirrored by skin-emitted acetone in three volunteers. Breath and skin acetone also clearly change with blood glucose and further work may ultimately enable inferences to be drawn of the blood glucose concentration from skin or breath measurements in type 1 diabetes. PMID:18215004

  8. Aerosol volatility in a boreal forest environment

    NASA Astrophysics Data System (ADS)

    Häkkinen, S. A. K.; ?ijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

    2012-04-01

    Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed during spring and autumn 2008. Results from the aerosol mass spectrometry indicate that the non-volatile residual consists of nitrate and organic compounds, especially during autumn. These compounds may be low-volatile organic nitrates or salts. During winter and spring the non-volatile core (black carbon removed) correlated markedly with carbon monoxide, which is a tracer of anthropogenic emissions. Due to this, the non-volatile residual may also contain other pollutants in addition to black carbon. Thus, it seems that the amount of different compounds in submicron aerosol particles varies with season and as a result the chemical composition of the non-volatile residual changes within a year. This work was supported by University of Helsinki three-year research grant No 490082 and Maj and Tor Nessling Foundation grant No 2010143. Aalto et al., (2001). Physical characterization of aerosol particles during nucleation events. Tellus B, 53, 344-358. Jayne, et al., (2000). Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Sci. Technol., 33(1-2), 49-70. Kalberer et al., (2004). Identification of Polymers as Major Components of Atmospheric Organic Aerosols. Science, 303, 1659-1662. Smith et al., (2010). Observations of aminium salts in atmospheric nanoparticles and possible climatic implications. P. Natl. Acad. Sci., 107(15). Vesala et al., (1998). Long-term field measurements of atmosphere-surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol physics and atmospheric chemistry. Trends Heat, Mass Mom. Trans., 4, 17-35. Wehner et al., (2002). Design and calibration of a thermodenuder with an improved heating unit to measure the size-dependent volatile fraction of aerosol particles. J. Aerosol Sci., 33, 1087-1093.

  9. Sodium channels as targets for volatile anesthetics.

    PubMed

    Herold, Karl F; Hemmings, Hugh C

    2012-01-01

    The molecular mechanisms of modern inhaled anesthetics are still poorly understood although they are widely used in clinical settings. Considerable evidence supports effects on membrane proteins including ligand- and voltage-gated ion channels of excitable cells. Na(+) channels are crucial to action potential initiation and propagation, and represent potential targets for volatile anesthetic effects on central nervous system depression. Inhibition of presynaptic Na(+) channels leads to reduced neurotransmitter release at the synapse and could therefore contribute to the mechanisms by which volatile anesthetics produce their characteristic end points: amnesia, unconsciousness, and immobility. Early studies on crayfish and squid giant axon showed inhibition of Na(+) currents by volatile anesthetics at high concentrations. Subsequent studies using native neuronal preparations and heterologous expression systems with various mammalian Na(+) channel isoforms implicated inhibition of presynaptic Na(+) channels in anesthetic actions at clinical concentrations. Volatile anesthetics reduce peak Na(+) current (I(Na)) and shift the voltage of half-maximal steady-state inactivation (h(?)) toward more negative potentials, thus stabilizing the fast-inactivated state. Furthermore recovery from fast-inactivation is slowed, together with enhanced use-dependent block during pulse train protocols. These effects can depress presynaptic excitability, depolarization and Ca(2+) entry, and ultimately reduce transmitter release. This reduction in transmitter release is more potent for glutamatergic compared to GABAergic terminals. Involvement of Na(+) channel inhibition in mediating the immobility caused by volatile anesthetics has been demonstrated in animal studies, in which intrathecal infusion of the Na(+) channel blocker tetrodotoxin increases volatile anesthetic potency, whereas infusion of the Na(+) channels agonist veratridine reduces anesthetic potency. These studies indicate that inhibition of presynaptic Na(+) channels by volatile anesthetics is involved in mediating some of their effects. PMID:22479247

  10. Conditional risk in volatility models Risk parameter in volatility models

    E-print Network

    Jeanjean, Louis

    Conditional risk in volatility models Risk parameter in volatility models Estimating the risk parameter Risk-parameter estimation in volatility models Christian Francq Jean-Michel Zakoïan CREST: http://mpra.ub.uni-muenchen.de/41713/ Francq, Zakoian Risk-parameter estimation in volatility models

  11. Variation of leaf gland volatile oil within a population of sweet gale ( Myrica gale ) (Myricaceae)

    Microsoft Academic Search

    Robert R. Carlton; Peter G. Waterman; Alexander I. Gray

    1992-01-01

    Summary The leaf gland volatile oils of ten sweet gale plants from a Scottish population were extracted in early summer. The results differed notably from reports of other populations in respect of the sesquiterpenes, ß-elemenone and germacrone, which were major components of the volatile oil. Three dihydrochalcones were also detected in the volatile oil. Variation within the population existed, particularly

  12. Evaluation of ?-radiation on green tea odor volatiles

    NASA Astrophysics Data System (ADS)

    Fanaro, G. B.; Duarte, R. C.; Araújo, M. M.; Purgatto, E.; Villavicencio, A. L. C. H.

    2011-01-01

    The aim of this study was to evaluate the gamma radiation effects on green tea odor volatiles in green tea at doses of 0, 5, 10, 15 and 20 kGy. The volatile organic compounds were extracted by hydrodistillation and analyzed by GC/MS. The green tea had a large influence on radiation effects, increasing the identified volatiles in relation to control samples. The dose of 10 kGy was responsible to form the majority of new odor compounds following by 5 and 20 kGy. However, the dose of 5 kGy was the dose that degraded the majority of volatiles in non-irradiated samples, following by 20 kGy. The dose of 15 kGy showed has no effect on odor volatiles. The gamma radiation, at dose up to 20 kGy, showed statistically no difference between irradiated and non irradiated green tea on odors compounds.

  13. Mantle Volatiles - Distribution and Consequences

    NASA Astrophysics Data System (ADS)

    Luth, R. W.

    2003-12-01

    Volatiles in the mantle have, for many years, been the subject of intensive study from a number of perspectives. They are of interest because of their potential effects on melting relationships, on transport of major and trace elements, and on the rheological and other physical properties of the mantle. By convention, "volatiles" in this context are constituents that are liquid or gaseous at normal Earth surface conditions. This review will look at the behavior of C-O-H-S-halogen volatiles, beginning with H2O and C-O volatiles.There have been tremendous strides made recently towards understanding how volatiles in general and water in particular is transported and stored in the mantle. This progress is based on research on a number of fronts: studies of mantle-derived samples have provided insight into the nature and occurrence of hydrous phases such as amphibole, mica, and chlorite, and have provided constraints on the capacity of nominally anhydrous minerals (NAMs) such as olivine, pyroxenes, and garnet to contain "water" by a variety of substitution mechanisms. Experimental studies on mantle-derived magmas have provided constraints on volatile contents in their source regions. Other studies have constrained the pressure, temperature, and composition conditions over which hydrous phases are stable in the mantle.Fundamental questions remain about the geochemical cycling of volatiles in the mantle, and between the mantle and the surface. Much attention has focused on the capability of hydrous phases such as amphibole, mica, serpentine, chlorite, and a family of "dense hydrous magnesian silicates" (DHMSs) to act as carriers of water in subducting slabs back into the mantle. It has been clear since the work of Ito et al. (1983) that there is a discrepancy between the amount of volatiles subducted into the mantle and those returned to the surface by arc magmatism. A recent overview of volatile cycling in subduction systems by Bebout (1996) suggests that 5-15% of the H2O and 10-44% of the CO2 that is subducted is returned to the surface in arc magmatism. He emphasized that the "missing" volatiles may have multiple fates, including incorporation into the mantle wedge, large-scale fluid flow up along the interface between the subducting slab and overlying mantle, and transport into the deeper mantle.Because of the hydrous nature of arc magmatism, a common hypothesis is that there is a hydrous phase that breaks down at subarc conditions to trigger melting in the overlying mantle wedge to produce arc magmas. A key research goal has been to identify this phase, or phases. For example, serpentine in peridotite will break down during subduction to produce olivine+orthopyroxene+fluid or, in cooler slabs, a progression of DHMSs, the last of which may survive into the transition zone.At some point, however, because of the limited thermal or pressure stability of the hydrous phases, water will be liberated from the slab into the surrounding mantle. At this point, the water will either exist as a fluid, a melt - or something intermediate if we are above the second critical end point in the relevant system (Wyllie and Ryabchikov, 2000) - or it may dissolve into nominally anhydrous phases.The understanding of the relevant phase relations for the other volatiles is not as advanced. For carbon, we have a reasonable understanding of its phase stability in the mantle, but there is still no good understanding of the relative importance of carbonates, elemental carbon, and other forms as hosts for carbon in the mantle. In the upper mantle, sulfur resides primarily in sulfides; their behavior during partial melting will play a major role in the geochemical cycling of sulfur as well as of chalcophile elements. The halogens are rare (and rarely studied) in mantle-derived samples; more insight into their behavior is currently coming from the study of mantle-derived magmas.This review will first consider the evidence from mantle-derived magmas pertaining to volatiles in the mantle, then turn to mantle-derived s

  14. Equilibrium analysis of volatility clustering

    Microsoft Academic Search

    Joel M. Vanden

    2005-01-01

    Volatility clustering is a pervasive feature of equity markets. This article studies volatility clustering in an equilibrium setting by generalizing the CRRA and CARA representative agent models of finance. In equilibrium, the market portfolio follows a volatility regime-switching process in which the volatility level is determined by the agent's local risk aversion. Using monthly data, the empirical tests reveal that

  15. Volatility and commodity price dynamics

    Microsoft Academic Search

    Robert S. Pindyck

    2004-01-01

    Commodity prices are volatile, and volatility itself varies over time. Changes in volatility can affect market variables by directly affecting the marginal value of storage, and by affecting a component of the total marginal cost of production, the opportunity cost of producing the commodity now rather than waiting for more price information. I examine the role of volatility in short-run

  16. Martian Volatiles and Isotopic Signatures

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.

    1997-01-01

    Data on martian volatiles gathered from Viking atmosphere measurements, modest groundbased spectra, shock-implanted atmospheric gases in martian (SNC) meteorites, trapped mantle gases in martian meteorites, and volatile-rich solid phases in martian meteorites, are presented. Atmospheric volatiles, surface volatiles, and isotopic chronologies are discussed, along with energetic particle interactions.

  17. Volatile einsteinium hexafluoroacetylacetonate complexes

    Microsoft Academic Search

    E. V. Fedoseev; M. I. Aizenberg; S. S. Travnikov; A. V. Davydov; B. F. Myasoedov

    1987-01-01

    Volatile einsteinium hexafluoroacetylacetonate complexes have been syntehsized. Their sublimation and thermochromatographic behaviour has been studied in the presence of -diketone vapours. Interaction of einsteinium di-and trichloride with hexafluoracetylacetone vapours is discussed.

  18. Low molecular weight (C1-C10) monocarboxylic acids, dissolved organic carbon and major inorganic ions in alpine snow pit sequence from a high mountain site, central Japan

    NASA Astrophysics Data System (ADS)

    Kawamura, Kimitaka; Matsumoto, Kohei; Tachibana, Eri; Aoki, Kazuma

    2012-12-01

    Snowpack samples were collected from a snow pit sequence (6 m in depth) at the Murodo-Daira site near the summit of Mt. Tateyama, central Japan, an outflow region of Asian dusts. The snow samples were analyzed for a homologous series of low molecular weight normal (C1-C10) and branched (iC4-iC6) monocarboxylic acids as well as aromatic (benzoic) and hydroxy (glycolic and lactic) acids, together with major inorganic ions and dissolved organic carbon (DOC). The molecular distributions of organic acids were characterized by a predominance of acetic (range 7.8-76.4 ng g-1-snow, av. 34.8 ng g-1) or formic acid (2.6-48.1 ng g-1, 27.7 ng g-1), followed by propionic acid (0.6-5.2 ng g-1, 2.8 ng g-1). Concentrations of normal organic acids generally decreased with an increase in carbon chain length, although nonanoic acid (C9) showed a maximum in the range of C5-C10. Higher concentrations were found in the snowpack samples containing dust layer. Benzoic acid (0.18-4.1 ng g-1, 1.4 ng g-1) showed positive correlation with nitrate (r = 0.70), sulfate (0.67), Na+ (0.78), Ca2+ (0.86) and Mg+ (0.75), suggesting that this aromatic acid is involved with anthropogenic sources and Asian dusts. Higher concentrations of Ca2+ and SO42- were found in the dusty snow samples. We found a weak positive correlation (r = 0.43) between formic acid and Ca2+, suggesting that gaseous formic acid may react with Asian dusts in the atmosphere during long-range transport. However, acetic acid did not show any positive correlations with major inorganic ions. Hydroxyacids (0.03-5.7 ng g-1, 1.5 ng g-1) were more abundant in the granular and dusty snow. Total monocarboxylic acids (16-130 ng g-1, 74 ng g-1) were found to account for 1-6% of DOC (270-1500 ng g-1, 630 ng g-1) in the snow samples.

  19. Seasonal Variability of Riverine Geochemistry (87Sr/86Sr, ?13CDIC, ?44/40Ca, and major ions) in Permafrost Watersheds on the North Slope of Alaska

    NASA Astrophysics Data System (ADS)

    Lehn, G. O.; Jacobson, A. D.; Douglas, T. A.; McClelland, J. W.; Khosh, M. S.; Barker, A. J.

    2014-12-01

    Global climate models predict amplified warming at high latitudes, where permafrost soils have historically acted as a carbon sink. As warming occurs, the seasonally thawed active layer will propagate downward into previously frozen mineral-rich soil, releasing carbon and introducing unique chemical weathering signatures into rivers. We use variations in the 87Sr/86Sr, ?13CDIC, ?44/40Ca, and major ion geochemistry of rivers to track seasonal active layer dynamics. We collected water from six streams on the North Slope of Alaska between May and October, 2009 and 2010. All rivers drain continuous permafrost but three drain tussock tundra-dominated watersheds and three drain steeper bedrock catchments with minor tundra coverage. In tundra streams, elevated 87Sr/86Sr ratios, low ?13CDIC values and major ions ([Na+]+[K+]/ [Ca+2]+[Mg+2]) in spring melt runoff suggest flushing of shallow soils with relatively low carbonate content. By July, 87Sr/86Sr ratios stabilize at relatively low values and ?13CDIC at relatively higher values, indicating the active layer thawed into deeper carbonate-rich soils. In bedrock streams, elevated 87Sr/86Sr ratios correlate with high discharge. By late fall, bedrock stream 87Sr/86Sr ratios decrease steadily, consistent with increased carbonate weathering. Nearly constant ?13CDIC values and high [SO4-2] for most of the melt season imply significant sulfuric acid-carbonate weathering in bedrock streams. ?13CDIC values suggest a shift to carbonic acid-carbonate weathering in late 2010, possibly due to limited oxygen for pyrite oxidation during freezing of the active layer. ?44/40Ca values in both tundra and bedrock streams increase during the seasons, suggesting increased uptake of 40Ca by plants. ?44/40Ca values of rivers are at least 0.1-0.2‰ higher than their watershed soils, rocks and sediments, suggesting significant plant uptake. Our findings show how seasonal changes in mineral weathering have potential for tracking active layer dynamics.

  20. Metabolomics of plant volatiles.

    PubMed

    Qualley, Anthony V; Dudareva, Natalia

    2009-01-01

    Plants communicate with their surrounding ecosystems using a diverse array of volatile metabolites that are indicative of the physiological status of the emitter. A variety of systems have been adapted to capture, analyze, identify, and quantify airborne metabolites released by plants. Metabolomic experiments typically involve four steps: sample collection, preparation, product separation, and data analysis. To date, two different types of headspace sampling, static and dynamic, are widely used for volatile metabolome investigation. For static headspace analysis, solid-phase microextraction (SPME) is used to sample volatiles while push and pull as well as closed-loop stripping methods are used for dynamic headspace sampling. After collection, volatile blends are most efficiently and routinely separated prior to analysis using gas chromatography (GC). Sample preparation is simplified because derivatization is not needed with volatile metabolites. GC coupled to detection by electron impact mass spectrometry (EI-MS) provides high chromatographic resolution, sensitivity, compound-specific detection, quantitation, and the potential to identify unknowns by characteristic and reproducible fragmentation spectra in addition to retention time. A variety of resources can be used to identify unknown compounds in a given volatile sample including >600,000 compounds with known mass spectra catalogued in searchable mass spectral libraries. PMID:19588114

  1. Using futures prices to filter short-term volatility and recover a latent, long-term price series for oil

    E-print Network

    Herce, Miguel Angel

    2006-01-01

    Oil prices are very volatile. But much of this volatility seems to reflect short-term,transitory factors that may have little or no influence on the price in the long run. Many major investment decisions should be guided ...

  2. Quality of major ion and total dissolved solids data from groundwater sampled by the National Water-Quality Assessment Program, 1992–2010

    USGS Publications Warehouse

    Gross, Eliza L.; Lindsey, Bruce D.; Rupert, Michael G.

    2012-01-01

    Field blank samples help determine the frequency and magnitude of contamination bias, and replicate samples help determine the sampling variability (error) of measured analyte concentrations. Quality control data were evaluated for calcium, magnesium, sodium, potassium, chloride, sulfate, fluoride, silica, and total dissolved solids. A 99-percent upper confidence limit is calculated from field blanks to assess the potential for contamination bias. For magnesium, potassium, chloride, sulfate, and fluoride, potential contamination in more than 95 percent of environmental samples is less than or equal to the common maximum reporting level. Contamination bias has little effect on measured concentrations greater than 4.74 mg/L (milligrams per liter) for calcium, 14.98 mg/L for silica, 4.9 mg/L for sodium, and 120 mg/L for total dissolved solids. Estimates of sampling variability are calculated for high and low ranges of concentration for major ions and total dissolved solids. Examples showing the calculation of confidence intervals and how to determine whether measured differences between two water samples are significant are presented.

  3. Volatiles in protoplanetary disks

    E-print Network

    Pontoppidan, Klaus M; Bergin, Edwin A; Brittain, Sean; Marty, Bernard; Mousis, Olvier; Oberg, Karin L

    2014-01-01

    Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the process of planet formation, forming the backbone of a rich chemistry that sets the initial conditions for the formation of planetary atmospheres, and act as a solid mass reservoir catalyzing the formation of planets and planetesimals. This growth has been driven by rapid advances in observations and models of protoplanetary disks, and by a deepening understanding of the cosmochemistry of the solar system. Indeed, it is only in the past few years that representative samples of molecules have been discovered in great abundance throughout protoplanetary disks - enough to begin building a complete budget for the most abundant elements after hydrogen and helium. The spatial distributions of key volatiles are being mapped...

  4. Sources of Terrestrial Volatiles

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.; Dones, L.

    1998-01-01

    Atmospheres are found enveloping those planets and satellites best able to hold them. The obvious conclusion is that volatile escape must have played nearly as great a role as volatile supply. A consequence of this view is that volatile supplies were probably much greater than the atmospheres that remain. The likeliest candidates are sources associated with the main events of planetary accretion itself such as volatile-rich planetesimals, or direct gravitational capture of nebular gases. Late asteroidal or cometary volatile-rich veneers are attractive, but they present quantitative difficulties. Comets in particular are inadequate, because the associated mass of stray comets that would have been scattered to the Oort Cloud or beyond is excessive. This difficulty applies to Uranus-Neptune planetesimals as well as to a putative massive early Kuiper Belt. Another potential problem with comets is that the D/H ratio in the three comets for which this has been measured is about twice that of Earth's oceans. Objects falling from a much augmented ancient asteroid belt remain a viable option, but timing is an issue: Can the depopulation of the asteroid belt be delayed long enough that it makes sense to talk of asteroids as a late veneer? Early accretion of asteroids as objects scattered into the maw of infant Earth makes more sense. Another appealing candidate population of volatile-rich objects for the inner solar system would be scattered planetesimals associated with the accretion of Jupiter, for two reasons: (1) Before there was Jupiter, there was no object in the solar system capable of expelling comets efficiently, and (2) the cross section of the inner solar system to stray objects was Greater when there were m many planetesimals.

  5. PREDICTING THE TOXICITY OF MAJOR IONS IN SEAWATER TO MYSID SHRIMP (MYSIDOPSIS BAHIA), SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS), AND INLAND SILVERSIDE MINNOW (MENIDIA BERYLLINA)

    EPA Science Inventory

    Although marine organisms are naturally adapted to salinities well above those of freshwater, elevated concentrations of specific ions have been shown to cause adverse effects on some saltwater species. Because some ions are also physiologically essential, a deficiency of these i...

  6. Predictive Inference for Integrated Volatility

    Microsoft Academic Search

    Valentina Corradi; Walter Distaso

    2011-01-01

    In recent years, numerous volatility-based derivative products have been engineered. This has led to interest in constructing conditional predictive den- sities and con¯dence intervals for integrated volatility. In this paper, we propose nonparametric estimators of the aforementioned quantities, based on model free volatility estimators. We establish consistency and asymptotic normality for the feasible estimators and study their ¯nite sample properties

  7. Financial Innovations and Macroeconomic Volatility

    Microsoft Academic Search

    Urban Jermann; Vincenzo Quadrini

    2006-01-01

    The volatility of US business cycles has declined during the last two decades. During the same period the financial structure of firms has become more volatile. In this paper we develop a model in which financial factors play a key role in generating economic fluctuations. Innovations in financial markets allow for greater financial flexibility and generate a lower volatility of

  8. Stochastic Volatility in DSGE models

    Microsoft Academic Search

    Giorgio Primiceri; Alejandro Justiniano

    2005-01-01

    A number of recent papers have concluded that stochastic volatility plays a prominent role in describing the business cycle, particularly for the characterization of monetary policy. The impact of including stochastic volatility in DSGE models remains, however, unexplored. This paper therefore deals with the estimation of DSGE models when structural innovations have volatilities that are allowed to vary over time.

  9. Analysis of volatile organic compounds from illicit cocaine samples

    SciTech Connect

    Robins, W.H.; Wright, B.W.

    1994-07-01

    Detection of illicit cocaine hydrochloride shipments can be improved if there is a greater understanding of the identity and quantity of volatile compounds present. This study provides preliminary data concerning the volatile organic compounds detected in a limited Set of cocaine hydrochloride samples. In all cases, cocaine was one of the major volatile compounds detected. Other tropeines were detected in almost all samples. Low concentrations of compounds that may be residues of processing solvents were observed in some samples. The equilibrium emissivity of. cocaine from cocaine hydrochloride was investigated and a value of 83 parts-per-trillion was determined.

  10. Atmospheric pressure chemical ionisation mass spectrometry for in vivo analysis of volatile flavour release

    Microsoft Academic Search

    A. J. Taylor; R. S. T. Linforth; B. A. Harvey; A. Blake

    2000-01-01

    To follow volatile flavour release in the expired air of people during eating, several physiological and analytical constraints must be observed to obtain good quality data. An interface has been developed to sample air from the nose and ionise the volatile compounds contained therein by atmospheric pressure chemical ionisation. The ions formed are detected in a quadrupole mass spectrometer. The

  11. How Markets Process Information: News Releases and Volatility

    Microsoft Academic Search

    Louis H Ederington; Jae Ha Lee

    1993-01-01

    The authors examine the impact of scheduled macroeconomic news announcements on interest rate and foreign exchange futures markets. They find these announcements are responsible for most of the observed time-of-day and day-of-the-week volatility patterns in these markets. While the bulk of the price adjustment to a major announcement occurs within the first minute, volatility remains substantially higher than normal for

  12. Multiple Regimes and Volatility Transmission in Securitized Real Estate Markets

    Microsoft Academic Search

    Kim Hiang Liow; Zhiwei Chen; Jingran Liu

    2011-01-01

    We examine the dynamics and transmission of conditional volatilities with multiple structural changes in return volatility\\u000a using Bai and Perron (2003)’s methodology, across five major securitized real estate markets as well as employing a multivariate regime-dependent asymmetric\\u000a dynamic covariance methodology (MRDADC) that allows the conditional matrix to be both time- and state-varying. Our results\\u000a imply that a multiple-regime time varying

  13. Time-varying volatility in Malaysian stock exchange: An empirical study using multiple-volatility-shift fractionally integrated model

    NASA Astrophysics Data System (ADS)

    Cheong, Chin Wen

    2008-02-01

    This article investigated the influences of structural breaks on the fractionally integrated time-varying volatility model in the Malaysian stock markets which included the Kuala Lumpur composite index and four major sectoral indices. A fractionally integrated time-varying volatility model combined with sudden changes is developed to study the possibility of structural change in the empirical data sets. Our empirical results showed substantial reduction in fractional differencing parameters after the inclusion of structural change during the Asian financial and currency crises. Moreover, the fractionally integrated model with sudden change in volatility performed better in the estimation and specification evaluations.

  14. Herbivore induced plant volatiles

    PubMed Central

    War, Abdul Rashid; Sharma, Hari Chand; Paulraj, Michael Gabriel; War, Mohd Yousf; Ignacimuthu, Savarimuthu

    2011-01-01

    Plants respond to herbivory through different defensive mechanisms. The induction of volatile emission is one of the important and immediate response of plants to herbivory. Herbivore-induced plant volatiles (HIPVs) are involved in plant communication with natural enemies of the insect herbivores, neighboring plants, and different parts of the damaged plant. Release of a wide variety of HIPVs in response to herbivore damage and their role in plant-plant, plant-carnivore and intraplant communications represents a new facet of the complex interactions among different trophic levels. HIPVs are released from leaves, flowers, and fruits into the atmosphere or into the soil from roots in response to herbivore attack. Moreover, HIPVs act as feeding and/or oviposition deterrents to insect pests. HIPVs also mediate the interactions between the plants and the microorganisms. This review presents an overview of HIPVs emitted by plants, their role in plant defense against herbivores and their implications for pest management. PMID:22105032

  15. Volatile analysis of ground almonds contaminated with naturally occurring fungi.

    PubMed

    Beck, John J; Mahoney, Noreen E; Cook, Daniel; Gee, Wai S

    2011-06-01

    Aflatoxigenic aspergilli inflict major economic damage to the tree nut industry of California, with the highest negative impact to almonds. Aspergilli and fungi in general are known to emit volatiles in varying quantity and composition dependent upon their growth media. The goal of the study was to determine the volatile emission of whole and blanched almonds that had been picked out and labeled as inedible by processors. The aflatoxin content and number of colony forming units of each sample were also determined. A total of 23 compounds were consistently detected and identified. Several volatiles from the blanched almonds demonstrated significant increases when compared to the emissions of whole almonds. Several of these volatiles are considered fatty acid decomposition products and included hexanal, heptanal, octanal, nonanal, 3-octen-2-one, tetramethylpyrazine, and decanal. The almond samples investigated were characteristic of a typical postharvest environment and illustrative of potential contamination within a stockpile or transport container. Volatiles indicative of fatty acid decomposition were predominant in the samples that underwent some form of blanching. The emission amounts of hexanal, heptanal, octanal, and hexanoic acid increased 3-fold in samples contaminated with aflatoxin; however, due to variability between samples they could not be considered as indicator volatiles for aflatoxin content. The emission profile of volatiles from almond kernels contaminated with naturally occurring aspergilli and associated fungi is heretofore unreported. PMID:21528918

  16. Exploring Metropolitan Housing Price Volatility

    Microsoft Academic Search

    Norman G. Miller; Liang Peng

    2003-01-01

    Abstract This paper uses MSA level data and a panel,VAR model,to analyze,the dynamic,determination and impact of the volatility of single-family home,value appreciation. We find that the volatility can be magnified by an exogenous increase in the home appreciation rate, responds to changes in the population growth rate, and is serially correlated. Moreover, an exogenous increase in the volatility increases the

  17. Classification of Volatile Engine Particles

    SciTech Connect

    Cheng, Mengdawn [ORNL] [ORNL

    2013-01-01

    Volatile particles cannot be detected at the engine exhaust by an aerosol detector. They are formed when the exhaust is mixed with ambient air downstream. Lack of a precise definition of volatile engine particles has been an impediment to engine manufacturers and regulatory agencies involved in the development of an effective control strategy. It is beyond doubt that volatile particles from combustion sources contribute to the atmospheric particulate burden, and the effect of that contribution is a critical issue in the ongoing research in the areas of air quality and climate change. A new instrument, called volatile particle separator (VPS), has been developed. It utilizes a proprietary microporous metallic membrane to separate particles from vapors. VPS data were used in the development of a two-parameter function to quantitatively classify, for the first time, the volatilization behavior of engine particles. The value of parameter A describes the volatilization potential of an aerosol. A nonvolatile particle has a larger A-value than a volatile one. The value of parameter k, an effective evaporation energy barrier, is found to be much smaller for small engine particles than that for large engine particles. The VPS instrument provides a means beyond just being a volatile particle remover; it enables a numerical definition to characterize volatile engine particles.

  18. THE ECONOMIC VALUE OF USING REALIZED VOLATILITY IN FORECASTING FUTURE IMPLIED VOLATILITY

    Microsoft Academic Search

    Wing Hong Chan; Ranjini Jha; Madhu Kalimipalli

    2009-01-01

    We examine the economic benefits of using realized volatility to forecast future implied volatility for pricing, trading, and hedging in the S&P 500 index options market. We propose an encompassing regression approach to forecast future implied volatility, and hence future option prices, by combining historical realized volatility and current implied volatility. Although the use of realized volatility results in superior

  19. Changes in volatile compounds and some physicochemical properties of European cranberrybush (Viburnum opulus L.) during ripening through traditional fermentation.

    PubMed

    Yilmaztekin, Murat; Sislioglu, Kubra

    2015-04-01

    The changes in volatile compounds and some physicochemical properties of European Cranberrybush (Viburnum opulus L.) were investigated during traditional fermentation. Using the principal component analysis (PCA), relations between volatile compounds and fermentation were associated with dynamics of these compounds. In total, 58 volatile compounds were identified, 3-methylbutanoic acid (25.4% to 66.4% of identified volatile compounds) being the major constituent in raw, 2-, 3-, and 4-mo fermented European Cranberrybush fruits, while 2-octanone was dominant in 1-mo fermented sample with a 30% of the total identified volatiles. The amount of total volatile compounds was increased in the 1st month of fermentation and then decreased gradually in the following months. Acids were the dominant volatile compounds in raw and 3- to 4-mo fermented European Cranberrybush. Ketones and alcohols had the highest percentage in total volatile compounds in the 2nd and 3rd months of fermentation, respectively. PMID:25808206

  20. Major Ion Geochemistry of Horseshoe Lake, Mammoth Lakes, California: Water Quality in a Region with Elevated CO2 from Sub-Surface Leakage

    NASA Astrophysics Data System (ADS)

    Santilena, R.; Szutu, D.; Ellis, A. S.; Khachikian, C. S.

    2010-12-01

    Tree-kill areas around Horseshoe Lake indicate how naturally high levels of carbon dioxide (CO2) emitted from a cooling magma chamber are affecting the ecosystem. CO2 leakage from geologically sequestered CO2 sites may have similar effects. Weathering processes and water quality changes are two other environmental impacts of high levels of CO2 leaking from subsurface CO2 reservoirs. This study’s focus was to conduct a geochemical study of Horseshoe Lake with emphasis on water chemistry to determine any quantifiable effects from the high release of volcanic CO2. We collected 22 water samples, including 5 samples from streams that drained into the lake. Two interior locations were sampled at the surface and at depths of 2-meter intervals. The interior lake samples showed increasing Mg and Ca concentrations from the surface to 12 m in depth, and increasing Sr and Si from the surface to 4 m in depth. Water samples were measured for temperature, conductivity, pH, alkalinity, and analyzed for major ions Ca2+, K+, Na+, Mg2+, Cl-, SO42-, and HCO3- (from alkalinity). Amounts of Al, Ca, K, Mg, Na, and high levels of Si from elemental data are consistent with waters in granitic environments. Temperature in the lakes and streams ranged from 3.5 to 16 °C, pH ranged from 5.9-7.2, conductivity ranged from 8.66 to 21.93 ?S/cm, and alkalinity ranged from 0.137- 0.408 meq/L. A TSI Q-Trak™ measured soil and ambient CO2 concentrations in July and a Vernier LabQuest was used in August. A bottomless bottle was placed in the soil in a10cm deep hole with the probe inserted in the top. A probe about 1 m above ground measured the ambient CO2 concentrations. To determine the flux of soil CO2, concentrations were read over a 5-minute time period. CO2 gas concentrations in the tree kill area ranged from 600 to 1,700 ppm in ambient air, and over 99,000 ppm in the soil. Maximum readings were exceeded so actual values of CO2 in the soil are not known. The stream samples had a different solute composition than the lake. Stream samples tended to have higher Al and Si concentrations than the lake. For Al 9.3 x 10-7 to 1.8 x 10-6 moles/L in the streams and 4.8 x 10-7 to 1.2 x 10-6 moles/L in the lake, and for Si 1.3 x 10-4 to 2.1 x 10 -4 moles/L in the streams, 1.1 x 10-4 to 1.2 x 10-4 moles/L in the lake. Stream samples had and lower concentrations of Mg and Ca than lake perimeter and interior surface samples. Values for Mg were 6.0 x 10-6 to 1.1 x 10-5 moles/L in the streams and about 1.1 x 10-5 in the lake, and for Ca 9.3 x 10-7 to 1.8 x 10-6 moles/L in the stream, 4.3 x 10-5 to 4.5 x 10-5 in the lake. The difference could be because of weathering processes or because of unknown other inputs such as springs or groundwater. Additionally, Horseshoe Lake may be stratified, with different solutes dominating at different depths. Evaporation from the lake could also cause more concentrated solutes in solution. The data was generally consistent with results from previous USGS, but our samples were more dilute showing the impact of high precipitation during 2009 and 2010.

  1. Volatile Compounds of Tufted Hairgrass

    Microsoft Academic Search

    Eric Watkins; Thomas J. Gianfagna; Rongqi Sun; William A. Meyer

    2006-01-01

    The primary limitation of tufted hairgrass (Deschampsia cespitosa (L.) P. Beauv.) as a turfgrass appears to be damage caused by bill- bug (Sphenophorus spp.) herbivory. In this study several sets of germ- plasm were used in volatile collection studies. Whole-plant volatile collections were made on: i) untreated plants, ii) plants that had been treated with jasmonic acid (JA), and iii)

  2. Two Essays On Idiosyncratic Volatility

    Microsoft Academic Search

    Adam R. Smedema

    2011-01-01

    In my dissertation, I investigate the pricing of idiosyncratic volatility in asset returns. Traditional models of asset returns assume that investors hold large, well-diversified portfolios. As such, only systematic risks should matter in the pricing of returns. Recent empirical research has shown that idiosyncratic volatility, in fact, does matter for asset returns. In my first essay, I focus on reviewing

  3. ANALYSIS OF VOLATILE COMPOUNDS FROM INFUSION AND HYDRODISTILLATE OBTAINED FROM THE SPECIES THYMUS PULEGIOIDES L. (LAMIACEAE)

    Microsoft Academic Search

    MARIANA PAVEL; ANA TEODOR; Carol Davila

    2009-01-01

    The volatile compounds present in the species belonging to the Thymus genus (Lamiaceae) are responsible for the two well defined therapeutic effects demonstrated for these plants: antiseptic and spasmolytic effects. The essential oil which contains the majority of these compounds is hardly accessible and, as consequence, it is rarely used by the patient. That's why an analysis of the volatile

  4. Subduction and volatile recycling in Earth's mantle

    NASA Technical Reports Server (NTRS)

    King, S. D.; Ita, J. J.; Staudigel, H.

    1994-01-01

    The subduction of water and other volatiles into the mantle from oceanic sediments and altered oceanic crust is the major source of volatile recycling in the mantle. Until now, the geotherms that have been used to estimate the amount of volatiles that are recycled at subduction zones have been produced using the hypothesis that the slab is rigid and undergoes no internal deformation. On the other hand, most fluid dynamical mantle flow calculations assume that the slab has no greater strength than the surrounding mantle. Both of these views are inconsistent with laboratory work on the deformation of mantle minerals at high pressures. We consider the effects of the strength of the slab using two-dimensional calculations of a slab-like thermal downwelling with an endothermic phase change. Because the rheology and composition of subducting slabs are uncertain, we consider a range of Clapeyron slopes which bound current laboratory estimates of the spinel to perovskite plus magnesiowustite phase transition and simple temperature-dependent rheologies based on an Arrhenius law diffusion mechanism. In uniform viscosity convection models, subducted material piles up above the phase change until the pile becomes gravitationally unstable and sinks into the lower mantle (the avalanche). Strong slabs moderate the 'catastrophic' effects of the instabilities seen in many constant-viscosity convection calculations; however, even in the strongest slabs we consider, there is some retardation of the slab descent due to the presence of the phase change.

  5. First volatile inventory for Gorely volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Aiuppa, A.; Giudice, G.; Liuzzo, M.; Tamburello, G.; Allard, P.; Calabrese, S.; Chaplygin, I.; McGonigle, A. J. S.; Taran, Y.

    2012-03-01

    We report here the very first assessment of volatile flux emissions from Gorely, an actively degassing volcano in Kamchatka. Using a variety of in situ and remote sensing techniques, we determined the bulk plume concentrations of major volatiles (H2O ˜93.5%, CO2, ˜2.6%, SO2 ˜2.2%, HCl 1.1%, HF 0.3%, H2 0.2%) and trace-halogens (Br, I), therefore estimating a total gas release of ˜11,000 tons·day-1 during September 2011, at which time the target was non-eruptively degassing at ˜900°C. Gorely is a typical arc emitter, contributing 0.3% and 1.6% of the total global fluxes from arc volcanism for CO2 and HCl, respectively. We show that Gorely's volcanic gas (H2O/SO2 ˜43, CO2/SO2 ˜1.2, HCl/SO2 ˜0.5) is a representative mean end-member for arc magmatism in the north-west Pacific region. On this basis we derive new constraints for the abundances and origins of volatiles in the subduction-modified mantle source which feeds magmatism in Kamchatka.

  6. Modelling financial volatility in the presence of abrupt changes

    NASA Astrophysics Data System (ADS)

    Ross, Gordon J.

    2013-01-01

    The volatility of financial instruments is rarely constant, and usually varies over time. This creates a phenomenon called volatility clustering, where large price movements on one day are followed by similarly large movements on successive days, creating temporal clusters. The GARCH model, which treats volatility as a drift process, is commonly used to capture this behaviour. However research suggests that volatility is often better described by a structural break model, where the volatility undergoes abrupt jumps in addition to drift. Most efforts to integrate these jumps into the GARCH methodology have resulted in models which are either very computationally demanding, or which make problematic assumptions about the distribution of the instruments, often assuming that they are Gaussian. We present a new approach which uses ideas from nonparametric statistics to identify structural break points without making such distributional assumptions, and then models drift separately within each identified regime. Using our method, we investigate the volatility of several major stock indexes, and find that our approach can potentially give an improved fit compared to more commonly used techniques.

  7. Statistical Analysis of Major Ion and Trace Element Geochemistry of Water, 1986-2006, at Seven Wells Transecting the Freshwater/Saline-Water Interface of the Edwards Aquifer, San Antonio, Texas

    USGS Publications Warehouse

    Mahler, Barbara J.

    2008-01-01

    This report by the U.S. Geological Survey, in cooperation with the San Antonio Water System, describes the results of a statistical analysis of major ion and trace element geochemistry of water at seven wells transecting the freshwater/saline-water interface of the Edwards aquifer in San Antonio, Texas, either over time or in response to variations in hydrologic conditions. The data used in this report were collected during 1986-2006. The seven monitoring wells are screened at different depths in the aquifer at three sites that form a generally north-to-south transect. The three wells of the southern site and the deeper of the two middle-site wells are open to the freshwater/saline-water transition zone, which contains saline water. The shallower well of the middle site and the two wells of the northern site are open to the freshwater zone. Mean specific conductance (SC) values were greater at transition-zone wells than at freshwater-zone wells, but SC did not vary systematically with depth. Concentrations of all major ions except bicarbonate were greater at transition-zone wells than at freshwater-zone wells, but concentrations tended to be more variable at freshwater-zone wells. Mean molar ratios of magnesium:calcium, sulfate:chloride, and sodium:chloride were similar at transition-zone wells and freshwater-zone wells. Concentrations of trace elements for many water samples at the seven transect wells were below the laboratory analytical reporting level. Detections of trace elements were more frequent at transition-zone wells, and mean concentrations of cadmium, chromium, copper, lead, and silver were elevated at transition-zone wells relative to freshwater-zone wells. All strong correlations between SC and major ions were positive, and in general there were more and stronger correlations between SC and major ions in the water from the freshwater-zone wells than from the transition-zone wells. Except for the shallowest transition-zone well, the transition-zone wells had relatively few strong correlations overall. The lack of a strong correlation indicates that much of the variability in the major ion concentrations at these wells might be a result of analytical variability caused by the multiple laboratory analytical methods used. In most cases, strong correlations between concentrations of trace elements were positive, and transition-zone wells and freshwater-zone wells had water with a similar number of significant correlations. Principal components analysis indicates dilution of ground water by low-ionic-strength meteoric water at the three freshwater-zone wells and at the shallowest transition-zone well. At the two deeper transition-zone wells at the southern site, principal components analysis indicates that there is no systematic variation in major ion concentrations. At three transition-zone wells, there was a general trend toward less salinity over the 21-year period of sampling. Trends in SC at the freshwater-zone wells were less consistent. There is no systematic change in the direction of trend in SC by water type (saline or fresh), between sites, or with depth. In general, trends in major ion concentrations corresponded to those in SC. For each trace element over the 21-year sampling period, there was either no trend or a downward trend. Relations between SC, major ions, and major ion molar ratios and hydrologic indicators (concurrent or prior time-averaged measures of water level and effective rainfall) were investigated. Correlations between geochemical variables and measures of water level in the freshwater-zone wells were much more frequent than correlations between geochemical variables and measures of water level in the transition-zone wells. There were correlations between SC and all measures of water level at the two freshwater-zone wells at the northern site, but there were no correlations between SC and any measures of water level at any transition-zone wells. SC was correlated with effe

  8. Plant Volatile Analogues Strengthen Attractiveness to Insect

    PubMed Central

    Sun, Yufeng; Yu, Hao; Zhou, Jing-Jiang; Pickett, John A.; Wu, Kongming

    2014-01-01

    Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of ?-ionone and benzaldehyde. The stabilities of ?-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than ?-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than ?-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety. PMID:24911460

  9. Interactions between wine volatile compounds and grape and wine matrix components influence aroma compound headspace partitioning.

    PubMed

    Robinson, Anthony L; Ebeler, Susan E; Heymann, Hildegarde; Boss, Paul K; Solomon, Peter S; Trengove, Robert D

    2009-11-11

    A full-factorial design was used to assess the matrix effects of ethanol, glucose, glycerol, catechin, and proline on the volatile partitioning of 20 volatile compounds considered to play a role in wine aroma. Analysis of variance showed that the two-way interactions of ethanol and glucose, ethanol and glycerol, and glycerol and catechin significantly influenced headspace partitioning of volatiles. Experiments were conducted to observe the effect of varied ethanol and glucose concentrations on headspace partitioning of a constant concentration of volatiles. Analysis of variance and linear regression analysis showed that the presence of glucose increased the concentration of volatiles in the headspace, whereas increasing ethanol concentration was negatively correlated with headspace partitioning of volatiles. A subsequent study assessed the effect of diluting white and red wines with water and ethanol. It was again observed that increased ethanol concentration significantly reduced the relative abundance of volatile compounds in the sample headspace. This study investigates some of the complex matrix interactions of the major components of grape and wine that influence volatile compound headspace partitioning. The magnitude of each matrix-volatile interaction was ethanol > glucose > glycerol > catechin, whereas proline showed no apparent interaction. The results clearly identify that increasing ethanol concentrations significantly reduce the headspace concentration of volatile aroma compounds, which may contribute to explaining recent sensory research observations that indicate ethanol can suppress the fruit aroma attributes in wine. PMID:19845354

  10. Lunar apatite with terrestrial volatile abundances Jeremy W. Boyce1,2

    E-print Network

    Perfect, Ed

    apatites in common terrestrial igneous rocks. These volatile contents could reflect post igneous rocks by measuring H, Cl and S contents of apatites in lunar basalt 14053 using secondary ion mass of indigenous H in lunar rocks. Here we report quantitative ion microprobe measurements of late-stage apatite

  11. Volatile phytochemicals as mosquito semiochemicals

    PubMed Central

    Nyasembe, Vincent O.; Torto, Baldwyn

    2014-01-01

    Plant biochemical processes result in the release of an array of volatile chemical substances into the environment, some of which are known to play important plant fitness enhancing functions, such as attracting pollinators, thermal tolerance of photosynthesis, and defense against herbivores. Cunningly, phytophagous insects have evolved mechanisms to utilize these volatiles to their own advantage, either to colonize a suitable host for feeding, reproduction and oviposition or avoid an unsuitable one. The volatile compounds involved in plant–insect chemical interactions have been widely exploited in the management of agricultural pests. On the other hand, use of plant volatiles in the management of medically important insects is limited, mainly due to paucity of information on their role in disease vector–plant interactions. To date, a total of 29 plant volatile compounds from various chemical classes, including phenols, aldehydes, alcohols, ketones and terpenes, have been identified as mosquito semiochemicals. In this review, we present highlights of mosquito–plant interactions, the available evidence of nectar feeding, with particular emphasis on sources of plant attractants, methods of plant volatile collection and the candidate plant volatile compounds that attract mosquitoes to nectar sources. We also highlight the potential application of these phytochemical attractants in integrated mosquito management. PMID:25383131

  12. Trading volume and stock market volatility: The Polish case

    Microsoft Academic Search

    Martin T. Bohl; Harald Henke

    2003-01-01

    Relying on the mixture of distributions hypothesis (MDH), this paper investigates the relationship between daily returns and trading volume for 20 Polish stocks. Our empirical results show that in the majority of cases volatility persistence tends to disappear when trading volume is included in the conditional variance equation, which is in agreement with the findings of studies on developed stock

  13. High Consumption Volatility: The Impact of Natural Disasters?

    Microsoft Academic Search

    Philippe Auffret

    2003-01-01

    A history of repeated external and domestic shocks has made economic insecurity a major concern across the Caribbean region. Of particular concern to all households, especially the poorest segments of the population, is the exposure to shocks that are generated by catastrophic events or natural disasters.Auffret shows that despite high consumption growth, the Caribbean region suffers from a high volatility

  14. Degradation of volatile fatty acids in highly efficient anaerobic digestion

    Microsoft Academic Search

    Qunhui Wang; Masaaki Kuninobu; Hiroaki I Ogawa; Yasuhiko Kato

    1999-01-01

    To improve the efficiency of anaerobic digestion, we examined the effects of C2–C6 volatile fatty acids (VFAs) on methane fermentation, as well as the behavior of VFAs in anaerobic digestion. The VFA concentrations and methane production in anaerobic digestion were increased by pretreatment of waste activated sludge (WAS), such as ultrasonic disintegration, thermal and freezing treatments. The major intermediate products

  15. Risky Business? Corporate Political Spending, Shareholder Approval, and Stock Volatility

    E-print Network

    Portman, Douglas

    Risky Business? Corporate Political Spending, Shareholder Approval, and Stock Volatility Saumya DiNapoli, announcing an agreement reached with five major corporations to disclose political spending political spending.1 According to the most comprehensive analysis of corporate political activity to date

  16. The Volatility of the Stock Market and News

    Microsoft Academic Search

    Rohitha Goonatilake; Susantha Herath

    The volatility of stock market indicators goes beyond anyone?s reasonable explanations. Industry performance, economic, and political changes are among the major factors that can affect the stock market. This paper focuses on the effect of news that surfaces throughout the day in the stock market. While there are many influences behind the constant changes in stock market performance, we can

  17. Oxidation of Volatile Organic Compounds in Aqueous Solution and

    E-print Network

    Winfree, Erik

    i Oxidation of Volatile Organic Compounds in Aqueous Solution and at the Air-water Interface ABSTRACT Isoprene (ISO), the most abundant non-methane VOC, is the major contributor to secondary organic. Current mechanisms, which are based on the oxidation of ISO in the gas-phase, underestimate SOA yields

  18. Polyatomic Ion Bingo

    NSDL National Science Digital Library

    Perkins School for the Blind

    2012-06-26

    This activity was designed for blind learners, but all types of learners can play this game to learn about the major polyatomic ions (an ion that consists of two different elements). This game helps learners memorize the chemical formulas and names for the major polyatomic ions, which also helps learners in writing more complex expressions in chemistry.

  19. VOLATILIZATION OF METHYL PARATHION FROM FIELDS TREATED WITH MICROENCAPSULATED AND EMULSIFIABLE CONCENTRATE FORMULATIONS

    EPA Science Inventory

    Volatilization of pesticides from treated agricultural crops constitutes a major input of these chemicals into the atmosphere. Microencapsulated pesticide formulations are designed for slow release of biocides and thus increase the residence time on the plant foliage. The rate of...

  20. TREATMENT OF CHLORINATED VOLATILE ORGANIC COMPOUNDS IN UPFLOW WETLAND MESOCOSMS. (R828773C003)

    EPA Science Inventory

    Sorption, biodegradation and hydraulic parameters were determined in the laboratory for two candidate soil substrate mixtures for construction of an upflow treatment wetland for volatile organic compounds (VOCs) at a Superfund site. The major parent contaminants in the groundw...

  1. Project EARTH-13-BW1: Volatile loss from planets and asteroids Supervisor: Bernard Wood

    E-print Network

    Project EARTH-13-BW1: Volatile loss from planets and asteroids Supervisor: Bernard Wood One of the major questions concerning the chemical and isotopic evolution of the terrestrial planets and asteroids

  2. Majors Exploration

    NSDL National Science Digital Library

    Prentice Hall (Prentice Hall)

    2012-01-05

    Put on your safari hat, open your mind and get ready to enter the world of majors explorations. If you ever wondered about a field of study and whether it is right for you, you are about to find out. You will also learn where majors and fields lead for careers that may interest you. All you need for the journey is the mind of the explorer and a commitment to thoroughly investigating the options which await you.

  3. Geographical traceability of Italian white truffle (Tuber magnatum Pico) by the analysis of volatile organic compounds.

    PubMed

    Gioacchini, Anna Maria; Menotta, Michele; Guescini, Michele; Saltarelli, Roberta; Ceccaroli, Paola; Amicucci, Antonella; Barbieri, Elena; Giomaro, Giovanna; Stocchi, Vilberto

    2008-10-01

    Results are presented that were obtained on the geographic traceability of the white truffle Tuber magnatum Pico. Solid-phase microextraction coupled to gas chromatography/mass spectrometry (SPME-GC/MS) was employed to characterize the volatile profile of T. magnatum white truffle produced in seven geographical areas of Italy. The main components of the volatile fraction were identified using SPME-GC/MS. Significant differences in the proportion of volatile constituents from truffles of different geographical areas were detected. The results suggest that, besides genetic factors, environmental conditions influence the formation of volatile organic compounds. The mass spectra of the volatile fraction of the samples were used as fingerprints to characterize the geographical origin. Next, stepwise factorial discriminant analysis afforded a limited number of characteristic fragment ions that allowed a geographical classification of the truffles studied. PMID:18798200

  4. Nonlinear Features of Realized FX Volatility

    Microsoft Academic Search

    John M. Maheu; Thomas H. McCurdy

    2001-01-01

    This paper investigates nonlinear features of FX volatility dynamics using estimates of daily volatility based on the sum of intraday squared returns. Measurement errors associated with using realized volatility to measure ex post latent volatility imply that standard time series models of the conditional variance become variants of an ARMAX model. We explore nonlinear departures from these linear specifications using

  5. Volatile Emission of Mechanically Damaged Almonds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mature almonds from the Monterey variety were evaluated for their volatile composition after mechanical damage and compared to the volatile composition of the corresponding undamaged almonds. Volatiles were collected on Tenax, desorbed with diethyl ether, and identified via GC-MS analyses. Volatile ...

  6. Volatile hexafluoroacetylacetonate complexes of einsteinium

    SciTech Connect

    Fedoseev, E.V.; Aizenberg, M.I.; Travnikov, S.S.; Davydov, A.V.; Myasoedov, B.F.

    1988-07-01

    Volatile hexafluoroacetylacetonate complexes of einsteinium have been synthesized. Their sublimation and thermochromatographic behavior in the presence of free ..beta..-diketone were studied. The reaction of einsteinium di- and tri-chlorides with hexafluoroacetylacetone vapor is discussed.

  7. Volatile hexafluoroacetylacetonate complexes of einsteinium

    Microsoft Academic Search

    E. V. Fedoseev; M. I. Aizenberg; S. S. Travnikov; A. V. Davydov; B. F. Myasoedov

    1988-01-01

    Volatile hexafluoroacetylacetonate complexes of einsteinium have been synthesized. Their sublimation and thermochromatographic behavior in the presence of free ..beta..-diketone were studied. The reaction of einsteinium di- and tri-chlorides with hexafluoroacetylacetone vapor is discussed.

  8. Changes in saffron volatile profile according to its storage time

    Microsoft Academic Search

    Luana Maggi; Manuel Carmona; Amaya Zalacain; Charalabos D. Kanakis; Eirini Anastasaki; Petros A. Tarantilis; Moschos G. Polissiou; Gonzalo L. Alonso

    2010-01-01

    Seventy-three saffron samples belonging to three different storage time (<1year, 3–4 and 8–9years) were analysed using ultrasound assisted extraction-gas chromatography–mass spectrometry and ultrasound assisted extraction-gas chromatography–olfactometry. Nineteen volatile compounds were identified and their aromatic notes were assigned. In addition to safranal, the main compound found, (30.14–43.94% in mass of total volatiles), other major compounds were 4-hydroxy-2,6,6-trimethyl-1-cyclohexen-1-carboxaldehyde and 3,5,5-trimethyl-2-cyclohexene-1-one. These compounds

  9. Fruit volatile analysis using an electronic nose.

    PubMed

    Vallone, Simona; Lloyd, Nathan W; Ebeler, Susan E; Zakharov, Florence

    2012-01-01

    Numerous and diverse physiological changes occur during fruit ripening, including the development of a specific volatile blend that characterizes fruit aroma. Maturity at harvest is one of the key factors influencing the flavor quality of fruits and vegetables. The validation of robust methods that rapidly assess fruit maturity and aroma quality would allow improved management of advanced breeding programs, production practices and postharvest handling. Over the last three decades, much research has been conducted to develop so-called electronic noses, which are devices able to rapidly detect odors and flavors. Currently there are several commercially available electronic noses able to perform volatile analysis, based on different technologies. The electronic nose used in our work (zNose, EST, Newbury Park, CA, USA), consists of ultra-fast gas chromatography coupled with a surface acoustic wave sensor (UFGC-SAW). This technology has already been tested for its ability to monitor quality of various commodities, including detection of deterioration in apple; ripeness and rot evaluation in mango; aroma profiling of thymus species; C(6) volatile compounds in grape berries; characterization of vegetable oil and detection of adulterants in virgin coconut oil. This system can perform the three major steps of aroma analysis: headspace sampling, separation of volatile compounds, and detection. In about one minute, the output, a chromatogram, is produced and, after a purging cycle, the instrument is ready for further analysis. The results obtained with the zNose can be compared to those of other gas-chromatographic systems by calculation of Kovats Indices (KI). Once the instrument has been tuned with an alkane standard solution, the retention times are automatically converted into KIs. However, slight changes in temperature and flow rate are expected to occur over time, causing retention times to drift. Also, depending on the polarity of the column stationary phase, the reproducibility of KI calculations can vary by several index units. A series of programs and graphical interfaces were therefore developed to compare calculated KIs among samples in a semi-automated fashion. These programs reduce the time required for chromatogram analysis of large data sets and minimize the potential for misinterpretation of the data when chromatograms are not perfectly aligned. We present a method for rapid volatile compound analysis in fruit. Sample preparation, data acquisition and handling procedures are also discussed. PMID:22491160

  10. Fruit Volatile Analysis Using an Electronic Nose

    PubMed Central

    Vallone, Simona; Lloyd, Nathan W.; Ebeler, Susan E.; Zakharov, Florence

    2012-01-01

    Numerous and diverse physiological changes occur during fruit ripening, including the development of a specific volatile blend that characterizes fruit aroma. Maturity at harvest is one of the key factors influencing the flavor quality of fruits and vegetables1. The validation of robust methods that rapidly assess fruit maturity and aroma quality would allow improved management of advanced breeding programs, production practices and postharvest handling. Over the last three decades, much research has been conducted to develop so-called electronic noses, which are devices able to rapidly detect odors and flavors2-4. Currently there are several commercially available electronic noses able to perform volatile analysis, based on different technologies. The electronic nose used in our work (zNose, EST, Newbury Park, CA, USA), consists of ultra-fast gas chromatography coupled with a surface acoustic wave sensor (UFGC-SAW). This technology has already been tested for its ability to monitor quality of various commodities, including detection of deterioration in apple5; ripeness and rot evaluation in mango6; aroma profiling of thymus species7; C6 volatile compounds in grape berries8; characterization of vegetable oil9 and detection of adulterants in virgin coconut oil10. This system can perform the three major steps of aroma analysis: headspace sampling, separation of volatile compounds, and detection. In about one minute, the output, a chromatogram, is produced and, after a purging cycle, the instrument is ready for further analysis. The results obtained with the zNose can be compared to those of other gas-chromatographic systems by calculation of Kovats Indices (KI). Once the instrument has been tuned with an alkane standard solution, the retention times are automatically converted into KIs. However, slight changes in temperature and flow rate are expected to occur over time, causing retention times to drift. Also, depending on the polarity of the column stationary phase, the reproducibility of KI calculations can vary by several index units11. A series of programs and graphical interfaces were therefore developed to compare calculated KIs among samples in a semi-automated fashion. These programs reduce the time required for chromatogram analysis of large data sets and minimize the potential for misinterpretation of the data when chromatograms are not perfectly aligned. We present a method for rapid volatile compound analysis in fruit. Sample preparation, data acquisition and handling procedures are also discussed. PMID:22491160

  11. Trends in volatile substance abuse.

    PubMed

    Spiller, Henry; Lorenz, Douglas J

    2009-01-01

    The purpose of this article is to evaluate whether social, geographic, and demographic factors have a relationship to trends in volatile substance abuse. Two datasets were obtained. Dataset 1 was all patients reported to U.S. poison centers with inhalation abuse of a non-pharmaceutical substance between 2000 and 2005. Dataset 2 was annual data from the U.S. Dept of Labor and U.S. Census Bureau for each of the 50 states for the years 2000 through 2005 for unemployment rate, population density, poverty rate, high school graduation rate and percentage of population with bachelor degree. The two datasets were compared for geographic (by state) and temporal (by year) relationships using U.S. government demographic categories. The U.S. poison centers state that 12,428 patients with volatile substance abuse have been reported over the 6 year period of 2000-2005, with a mean of 2,071 patients annually. A strong negative trend was found between volatile substance abuse and population density, with volatile substance abuse increasing as population density decreased. This trend remained consistent over the 6 years of evaluation. A negative trend was found with percentage of population with a bachelor's degree and volatile substance abuse. No trend was found when comparing volatile substance abuse and poverty rate, unemployment rate, or high school graduation rate. Volatile substance abuse appears to increase as population density decreases, following a previously suggested relationship with a rural setting. Volatile substance abuse appears to increase as percentage of population with a bachelor's degree decreases. PMID:19340679

  12. Using stable isotopes and major ions to identify hydrological processes and geochemical characteristics in a typical karstic basin, Guizhou, Southwest China.

    PubMed

    Han, Zhiwei; Tang, Changyuan; Wu, Pan; Zhang, Ruixue; Zhang, Chipeng

    2014-01-01

    The investigation of hydrological processes is very important for water resource development in karst basins. In order to understand these processes associated with complex hydrogeochemical evolution, a typical basin was chosen in Houzai, southwest China. The basin was hydrogeologically classified into three zones based on hydrogen and oxygen isotopes as well as the field surveys. Isotopic values were found to be enriched in zone 2 where paddy fields were prevailing with well-developed underground flow systems, and heavier than those in zone 1. Zone 3 was considered as the mixture of zones 1 and 2 with isotopic values falling in the range between the two zones. A conceptual hydrological model was thus proposed to reveal the probable hydrological cycle in the basin. In addition, major processes of long-term chemical weathering in the karstic basin were discussed, and reactions between water and carbonate rocks proved to be the main geochemical processes in karst aquifers. PMID:24437667

  13. Major depression.

    PubMed

    Bentley, Susan M; Pagalilauan, Genevieve L; Simpson, Scott A

    2014-09-01

    Major depression is a common, disabling condition seen frequently in primary care practices. Non-psychiatrist ambulatory providers are increasingly responsible for diagnosing, and primarily managing patients suffering from major depressive disorder (MDD). The goal of this review is to help primary care providers to understand the natural history of MDD, identify practical tools for screening, and a thoughtful approach to management. Clinically challenging topics like co-morbid conditions, treatment resistant depression and pharmacotherapy selection with consideration to side effects and medication interactions, are also covered. PMID:25134869

  14. Volatility from copper and tungsten alloys for fusion reactor applications

    SciTech Connect

    Smolik, G.R.; Neilson, R.M. Jr.; Piet, S.J. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

    1989-01-01

    Accident scenarios for fusion power plants present the potential for release and transport of activated constituents volatilized from first wall and structural materials. The extent of possible mobilization and transport of these activated species, many of which are oxidation driven'', is being addressed by the Fusion Safety Program at the Idaho National Engineering Laboratory (INEL). This report presents experimental measurements of volatilization from a copper alloy in air and steam and from a tungsten alloy in air. The major elements released included zinc from the copper alloy and rhenium and tungsten from the tungsten alloy. Volatilization rates of several constituents of these alloys over temperatures ranging from 400 to 1200{degree}C are presented. These values represent release rates recommended for use in accident assessment calculations. 8 refs., 3 figs., 5 tabs.

  15. Areal distribution of selected trace elements, salinity, and major ions in shallow ground water, Tulare Basin, Southern San Joaquin Valley, California

    USGS Publications Warehouse

    Fujii, Roger; Swain, W.C.

    1995-01-01

    The distribution of salinity and selected trace elements in shallow ground water in the Tulare Basin, California, was assessed to evaluate potential problems related to disposal in evaporation ponds of irrigation drain water containing elevated concentrations of selenium and other trace elements. The constituents of primary concern were selenium, arsenic, and salinity; uranium, boron, and molybdenum also were evaluated. Samples from 117 shallow wells were analyzed, and the results for samples from 110 of the wells were interpreted in relation to surficial geology, sediment depositional environment, soil characteristics, and hydrologic processes to determine the geochemical and hydrologic factors affecting the distribution of these constituents in ground water. In general, shallow ground water in areas where concentrations of salinity and most trace elements are elevated is influenced primarily by sediments derived from marine sedimentary rocks originating in the Coast Range, San Emigdio Mountains, and Tehachapi Mountains, and probably by unusual exposures of similar marine formations in the Sierra Nevada. Ground water in areas where concentrations of salinity and trace elements are significantly lower generally is influenced by igneous and metamorphic rocks exposed in the Sierra Nevada. In addition to sources of sediments, evaporation of shallow ground water, as indicated by isotopic enrichment of oxygen-18 and deuterium, increases salinity and concentrations of conservative trace elements such as selenium (under oxidizing conditions) and boron. Redox conditions affect the oxidation state of all trace elements of concern, except boron, and were found to be a major influence on trace-element solubility. Under oxidized conditions, selenate predominates and behaves conservatively, and arsenate predominates and is affected by sorption reactions that can limit arsenic solubility. Under reduced conditions, selenium is reduced to insoluble elemental selenium and arsenite predominates and generally is more soluble than arsenate. Elevated concentrations of uranium in shallow ground water probably are associated with uranium deposits in Kern County and other parts of the basin where oxidized conditions cause the more solubleuranyl species to predominate. Boron was correlated with salinity and behaved conservatively, whereas adsorption and precipitation of molybdenum minerals probably limited molybdenum solubility. Inter- relations among constituents were examined with principal component analysis. The first two principal components explained 50.7 percent of the variance in the data. The first principal component was related to salinity, and the second principal component was related to redox conditions, reflecting two of the major influences on shallow ground-water quality found in this study.

  16. First Evidence of a Volatile Sex Pheromone in Lady Beetles

    PubMed Central

    Fassotte, Bérénice; Fischer, Christophe; Durieux, Delphine; Lognay, Georges; Haubruge, Eric; Francis, Frédéric; Verheggen, François J.

    2014-01-01

    To date, volatile sex pheromones have not been identified in the Coccinellidae family; yet, various studies have suggested that such semiochemicals exist. Here, we collected volatile chemicals released by virgin females of the multicolored Asian lady beetle, Harmonia axyridis (Pallas), which were either allowed or not allowed to feed on aphids. Virgin females in the presence of aphids, exhibited “calling behavior”, which is commonly associated with the emission of a sex pheromone in several Coleoptera species. These calling females were found to release a blend of volatile compounds that is involved in the remote attraction (i.e., from a distance) of males. Gas Chromatography-Mass Spectrometry (GC-MS) analyses revealed that (–)-?-caryophyllene was the major constituent of the volatile blend (ranging from 80 to 86%), with four other chemical components also being present; ?-elemene, methyl-eugenol, ?-humulene, and ?-bulnesene. In a second set of experiments, the emission of the five constituents identified from the blend was quantified daily over a 9-day period after exposure to aphids. We found that the quantity of all five chemicals significantly increased across the experimental period. Finally, we evaluated the activity of a synthetic blend of these chemicals by performing bioassays which demonstrated the same attractive effect in males only. The results confirm that female H. axyridis produce a volatile sex pheromone. These findings have potential in the development of more specific and efficient biological pest-control management methods aimed at manipulating the behavior of this invasive lady beetle. PMID:25514321

  17. [Allelopathy and chemical constituents of Ligularia virgaurea volatile].

    PubMed

    Ma, Ruijun; Wang, Mingli; Zhu, Xuetai; Lu, Xianwen; Sun, Kun

    2005-10-01

    Ligularia virgaurea is a noxious weed widely distributed on the psychro-grasslands of east Qinghai-Tibet Plateau of China, but the allelopathic effects of its volatile is less known. In this study, the allelopathy of L. virgaurea volatile to 5 kinds of grasses was examined, and its chemical constituents were analyzed by GC-MS. The results demonstrated that the volatile of growing L. virgaurea could inhibit the seed germination speed and germination rate of all tested grasses. The inhibitory effects on Elymus nutans and Bromus magnus were significant, while Poa annua and Festuca ovin were not very sensitive. 18 major constituents were identified from the essential oil of L. virgaurea, accounted for 68.24% of the total. The main chemical components were 2-methylheptane (9.84%), 3-methyl-heptane (8.25%), heptane (7.93%), 4-methyl-1-(methylethyl)-bicyclo [3, 1, 0] hex-2-ene (7.79%), 3-methyl-hexane (6.38%), 2-methyl-hexane (5.54%), and D-limonene (4.70%). Monoterpenoids accounted for 16.58% of the total, indicating that volatilization was one of the ways by which L. virgaurea released allelochemicals. The allelopathy of the volatile may play an important role in enhancing the competitive ability of the species, and be one of reasons of grassland degeneration. PMID:16422498

  18. Modulation of volatile sulfur compounds by wine yeast.

    PubMed

    Swiegers, J H; Pretorius, I S

    2007-04-01

    Sulfur compounds in wine can be a 'double-edged sword'. On the one hand, certain sulfur-containing volatile compounds such as hydrogen sulfide, imparting a rotten egg-like aroma, can have a negative impact on the perceived quality of the wine, and on the other hand, some sulfur compounds such as 3-mercaptohexanol, imparting fruitiness, can have a positive impact on wine flavor and aroma. Furthermore, these compounds can become less or more attractive or repulsive depending on their absolute and relative concentrations. This presents an interesting challenge to the winemaker to modulate the concentrations of these quality-determining compounds in wine in accordance with consumer preferences. The wine yeast Saccharomyces cerevisiae plays a central role in the production of volatile sulfur compounds. Through the sulfate reduction sequence pathway, the HS(-) is formed, which can lead to the formation of hydrogen sulfide and various mercaptan compounds. Therefore, limiting the formation of the HS(-) ion is an important target in metabolic engineering of wine yeast. The wine yeast is also responsible for the transformation of non-volatile sulfur precursors, present in the grape, to volatile, flavor-active thiol compounds. In particular, 4-mercapto-4-methylpentan-2-one, 3-mercaptohexanol, and 3-mercaptohexyl acetate are the most important volatile thiols adding fruitiness to wine. This paper briefly reviews the metabolic processes involved in the production of important volatile sulfur compounds and the latest strategies in the pursuit of developing wine yeast strains as tools to adjust wine aroma to market specifications. PMID:17262212

  19. [In-situ measurement on volatilization loss of ammonia in the vegetable field and its influencing factors].

    PubMed

    Gong, Wei-Wei; Zhang, Yi-Sheng; He, Ling-Yan; Luan, Sheng-Ji

    2011-02-01

    In order to obtain ammonia volatilization flux and volatilization loss rate in the vegetable field and investigate their relationship with environmental factors, an on-line monitoring system was used to measure the ammonia volatilization in the vegetable (Brassica rapa L. and lettuce) field after urea application during January to September, 2009. The system included a wind tunnel system, a gas collector and an online analyzer system with ion chromatography. The time resolution of measurement was 15 min. The recovery of the system was (92.6 +/- 3.4)%; the accumulated ammonia volatilization within 15 d continuous sampling after fertilization was regarded as the total loss. The accumulated ammonia volatilization of 12 d continuous sampling after fertilization accounted for (85.4 +/- 5.2)% of the total volatilization. The ammonia volatilization loss of broadcasting basal dressing and top dressing for Brassica rapa L. were 23.6% and 21.3%, respectively. The ammonia volatilization loss of holing basal dressing and top dressing for lettuce were 17.6% and 24.0%, respectively. The ammonia volatilization in the vegetable field mostly occurred in the first 2-3 weeks after fertilization. The ammonia volatilization flux had significant positive correlation with the nitrogen application rate, while the ammonia volatilization loss rate had negative correlation with the nitrogen application rate. The ammonia volatilization flux was positively correlated with the soil temperature (r = 0.041, p < 0.05) and the air temperature (r = 0.049, p < 0.01), while not significantly associated with the air humidity and the soil moisture. Temperature was found to be a main factor influencing the ammonia volatilization in the vegetable field. PMID:21528553

  20. Biogenic volatile organic compound analyses by PTR-TOF-MS: Calibration, humidity effect and reduced electric field dependency.

    PubMed

    Pang, Xiaobing

    2015-06-01

    Green leaf volatiles (GLVs) emitted by plants after stress or damage induction are a major part of biogenic volatile organic compounds (BVOCs). Proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) is a high-resolution and sensitive technique for in situ GLV analyses, while its performance is dramatically influenced by humidity, electric field, etc. In this study the influence of gas humidity and the effect of reduced field (E/N) were examined in addition to measuring calibration curves for the GLVs. Calibration curves measured for seven of the GLVs in dry air were linear, with sensitivities ranging from 5 to 10ncps/ppbv (normalized counts per second/parts per billion by volume). The sensitivities for most GLV analyses were found to increase by between 20% and 35% when the humidity of the sample gas was raised from 0% to 70% relative humidity (RH) at 21°C, with the exception of (E)-2-hexenol. Product ion branching ratios were also affected by humidity, with the relative abundance of the protonated molecular ions and higher mass fragment ions increasing with humidity. The effect of reduced field (E/N) on the fragmentation of GLVs was examined in the drift tube of the PTR-TOF-MS. The structurally similar GLVs are acutely susceptible to fragmentation following ionization and the fragmentation patterns are highly dependent on E/N. Overall the measured fragmentation patterns contain sufficient information to permit at least partial separation and identification of the isomeric GLVs by looking at differences in their fragmentation patterns at high and low E/N. PMID:26040746

  1. Pyrolysis of Spent Ion Exchange Resins - 12210

    SciTech Connect

    Braehler, Georg; Slametschka, Rainer [NUKEM Technologies GmbH (Germany)

    2012-07-01

    Organic ion exchangers (IEX) play a major and increasing role in the reactor coolant and other water purification processes. During their operation time they receive significant amounts of radioactivity, making their disposal, together with their organic nature, as medium active waste challenging. Processes applied so far do not eliminate the organic matter, which is unwanted in disposal facilities, or, if high temperatures are applied, raise problems with volatile radionuclides. NUKEM Technologies offers their well introduces process for the destruction of spent solvent (TBP), the pebble bed pyrolysis, now for the treatment of spent IEX (and other problematic waste), with the following benefits: the pyrolysis product is free of organic matter, and the operation temperature with approx. 500 deg. C keeps Cs radionuclides completely in the solid residue. (authors)

  2. Journal of Chemical Ecology, Vol. 28, No. 3, March 2002 (C 2002) VOLATILE PRODUCTION BY BUDS AND COROLLAS OF

    E-print Network

    Irwin, Rebecca E.

    Journal of Chemical Ecology, Vol. 28, No. 3, March 2002 (C 2002) VOLATILE PRODUCTION BY BUDS spectrometry to identify and quantify the major volatile compounds produced by the buds and corollas a common predispersal seed predator that oviposits under the calyces of buds. Ipomopsis aggregata buds

  3. Implications of low SOA volatility and fragmentation reactions on the evolution of SOA in the atmosphere

    NASA Astrophysics Data System (ADS)

    Shrivastava, M.; Zelenyuk, A.; Imre, D. G.; Easter, R. C.; Beranek, J.; Zaveri, R. A.; Fast, J. D.

    2012-12-01

    We investigate the issues of low SOA volatility and gas-phase fragmentation reactions using both box and 3D model simulations. Analyzing both the laboratory and field data, we show that the observed slow evaporation behavior of SOA implies very low "effective volatility", under any realistic assumptions of mass accommodation coefficient. This analysis suggests that models may need to use different parameters to represent SOA formation versus its atmospheric evolution. A 5-product volatility basis set fit of ambient SOA evaporation rate measurements during the CARES field campaign show that a major fraction of the ambient SOA could be considered to be non-volatile under most atmospheric conditions. Accordingly, we revise our models to transform SOA "after formation" to a non-volatile non-absorbing organic aerosol (OA). We also develop simplified parameterizations to capture the first order effects of gas-phase fragmentation reactions. Using the box model, we show that, regardless of the fragmentation scheme, all multigenerational chemistry parameterizations predict one to two orders of magnitude higher SOA compared to models based on fixed smog chamber SOA yields. Increasing the amount of fragmentation reduces SOA loadings as expected. In addition, the box model shows that in our non-volatile SOA approach too, similar to the semi-volatile approach, the SOA is comprised of multi-generational oxidation products. But peak values of simulated O/C ratio are lower in the semi-volatile as compared to the non-volatile approach. Using the 3D model, we demonstrate complex variations in spatial and temporal distribution of SOA with varying degrees of fragmentation and the treatment of SOA as semi-volatile or non-volatile.

  4. Syrtis Major

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 1 May 2002) The Science This image is from the region of Syrtis Major, which is dominated by a low-relief shield volcano. This area is believed to be an area of vigorous aeolian activity with strong winds in the east-west direction. The effects of these winds are observed as relatively bright streaks across the image, extending from topographic features such as craters. The brighter surface material probably indicates a smaller relative particle size in these areas, as finer particles have a higher albedo. The bright streaks seen off of craters are believed to have formed during dust storms. A raised crater rim can cause a reduction in the wind velocity directly behind it, which results in finer particles being preferentially deposited in this location. In the top half of the image, there is a large bright streak that crosses the entire image. There is no obvious topographic obstacle, therefore it is unclear whether it was formed in the same manner as described above. This image is located northwest of Nili Patera, a large caldera in Syrtis Major. Different flows from the caldera eruptions can be recognized as raised ridges, representing the edge of a flow lobe. The Story In the 17th century, Holland was in its Golden Age, a time of cultural greatness and immense political and economic influence in the world. In that time, lived a inquisitive person named Christian Huygens. As a boy, he loved to draw and to figure out problems in mathematics. As a man, he used these talents to make the first detailed drawings of the Martian surface - - only 50 years or so after Galileo first turned his telescope on Mars. Mars suddenly became something other than a small red dot in the sky. One of the drawings Huygens made was of a dark marking on the red planet's surface named Syrtis Major. Almost 350 years later, here we are with an orbiter that can show us this place in detail. Exploration lives! It's great we can study this area up close. In earlier periods of history, scientists were fascinated with Syrtis Major because this dark region varied so much through the seasons and years. Some people thought it might be a changing sea, and others thought it might be vegetation. Early spacecraft like Mariner and Viking revealed for the first time that the changes were caused by the wind blowing dust and sand across the surface. What we can see in this image is exactly that: evidence of a lot of wind action. Bright dust patches streak across this image, formed through wind interference from craters and other landforms. These wispy, bright streaks are spread on the surface by a vigorous, east-west wind that kicked up huge dust storms, scattering the fine particles of sand and dust in an almost etherial pattern. The bright streaks in the top part of the image might have formed in a slightly different way, because there is no landform standing in the wind's way. Beneath the bright surface dust are raised ridges that mark the edges of earlier lava flows from Nili Patera, a Martian 'caldera.' A caldera is a collapsed, bowl-shaped depression at the top of a volcano cone. Can you imagine how Christian Huygens would feel if he lived today and could see all of this knowledge unfold? Or how it would feel to be the first person to stand in this dark volcanic and cratered region, knowing how many discovers had paved the way to that moment? Yes, exploration lives!

  5. Changes in streamflow and summary of major-ion chemistry and loads in the North Fork Red River basin upstream from Lake Altus, northwestern Texas and western Oklahoma, 1945-1999

    USGS Publications Warehouse

    Smith, S. Jerrod; Wahl, Kenneth L.

    2003-01-01

    Upstream from Lake Altus, the North Fork Red River drains an area of 2,515 square miles. The quantity and quality of surface water are major concerns at Lake Altus, and water-resource managers and consumers need historical information to make informed decisions about future development. The Lugert-Altus Irrigation District relies on withdrawals from the lake to sustain nearly 46,000 acres of agricultural land. Kendall's tau tests of precipitation data indicated no statistically significant trend over the entire 100 years of available record. However, a significant increase in precipitation occurred in the last 51 years. Four streamflow-gaging stations with more than 10 years of record were maintained in the basin. These stations recorded no significant trends in annual streamflow volume. Two stations, however, had significant increasing trends in the base-flow index, and three had significant decreasing trends in annual peak flows. Major-ion chemistry in the North Fork Red River is closely related to the chemical composition of the underlying bedrock. Two main lithologies are represented in the basin upstream from Lake Altus. In the upper reaches, young and poorly consolidated sediments include a range of sizes from coarse gravel to silt and clay. Nearsurface horizons commonly are cemented as calcium carbonate caliche. Finer-grained gypsiferous sandstones and shales dominate the lower reaches of the basin. A distinct increase in dissolved solids, specifically sodium, chloride, calcium, and sulfate, occurs as the river flows over rocks that contain substantial quantities of gypsum, anhydrite, and dolomite. These natural salts are the major dissolved constituents in the North Fork Red River.

  6. Volatility in natural gas and oil markets

    E-print Network

    Pindyck, Robert S.

    2003-01-01

    Using daily futures price data, I examine the behavior of natural gas and crude oil price volatility since 1990. I test whether there has been a significant trend in volatility, whether there was a short-term increase in ...

  7. Volatiles in interplanetary dust particles: a review.

    PubMed

    Gibson, E K

    1992-03-25

    The paper presents a review of the volatiles found within interplanetary dust particles. These particles have been shown to represent primitive material from early in the solar system's formation and also may contain records of stellar processes. The organogenic elements (i.e., H, C, N, O, and S) are among the most abundant elements in our solar system, and their abundances, distributions, and isotopic compositions in early solar system materials permit workers to better understand the processes operating early in the evolutionary history of solar system materials. Interplanetary dust particles have a range of elemental compositions, but generally they have been shown to be similar to carbonaceous chondrites, the solar photosphere, Comet Halley's chondritic cores, and matrix materials of chondritic chondrites. Recovery and analysis of interplanetary dust particles have opened new opportunities for analysis of primitive materials, although interplanetary dust particles represent major challenges to the analyst because of their small size. PMID:11537855

  8. Measuring Volatility Clustering in Stock Markets

    E-print Network

    Oh, Gabjin; Eom, Cheoljun; Kim, Taehyuk

    2007-01-01

    We propose a novel method to quantify the clustering behavior in a complex time series and apply it to a high-frequency data of the financial markets. We find that regardless of used data sets, all data exhibits the volatility clustering properties, whereas those which filtered the volatility clustering effect by using the GARCH model reduce volatility clustering significantly. The result confirms that our method can measure the volatility clustering effect in financial market.

  9. Challenges in quantitative analyses for volatile organic compounds bound to lipocalins.

    PubMed

    Kwak, Jae

    2012-11-01

    In this communication, I describe the challenges in quantitative analyses for volatile organic compounds in mouse urine, which are primarily caused by the presence of the major urinary proteins, a lipocalin subfamily, that sequester volatile ligands. The analyses of volatile compounds in mouse urine have been performed since the late 1970s. However, none of them considered the binding interactions of the quantified compounds with the urinary proteins. Some volatile ligands are tightly bound to the proteins and may not be extracted completely by organic solvents. The amounts of volatile ligands measured by external standard calibration represent those of the unbound ligands in the headspace, not the total amounts in urine. Addition of internal standards displaces ligands bound to the proteins, resulting in a completely different volatile profile. Normalization of volatile compounds using relative peak area (or height) ratios may not be used in the conditions where displacement of ligands bound to the proteins occurs. Because of the unique chemical properties of mouse urine, I have not been able to find a good quantification method for the volatile compounds released from mouse urine. I hope that the identification of these issues will stimulate others to come up with novel approaches. PMID:22965638

  10. Mars' volatile and climate history

    Microsoft Academic Search

    Bruce M. Jakosky; Roger J. Phillips

    2001-01-01

    There is substantial evidence that the martian volatile inventory and climate have changed markedly throughout the planet's history. Clues come from areas as disparate as the history and properties of the deep interior, the composition of the crust and regolith, the morphology of the surface, composition of the present-day atmosphere, and the nature of the interactions between the upper atmosphere

  11. A Volatile Product from Radium

    Microsoft Academic Search

    Harriet Brooks

    1904-01-01

    IN the course of some recent experiments on the excited radio-activity from the radium emanation, some evidence has been obtained which points to the conclusion that the oemanation X of radium at one stage of the changes which it undergoes after being deposited on a solid body is slightly volatile even at ordinary temperatures. The effect which gives rise to

  12. 5, 463499, 2008 Oxygenated volatiles

    E-print Network

    Boyer, Edmond

    of flooding on the exchange of the volatile C2-compounds ethanol, acetaldehyde and acetic acid between leaves Discussion EGU Abstract The effect of root inundation on the leaf emissions of ethanol, acetaldehyde significant emissions of any of the compounds. A slight deposition of acetaldehyde and acetic acid was mainly

  13. Syrtis Major

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 6 June 2002) The Science This image, located near the equator and 288W (72E), is near the southern edge of a low, broad volcanic feature called Syrtis Major. A close look at this image reveals a wrinkly texture that indicates a very rough surface that is associated with the lava flows that cover this region. On a larger scale, there are numerous bright streaks that trail topographic features such as craters. These bright streaks are in the wind shadows of the craters where dust that settles onto the surface is not as easily scoured away. It is important to note that these streaks are only bright in a relative sense to the surrounding image. Syrtis Major is one of the darkest regions on Mars and it is as dark as fresh basalt flows or dunes are on Earth. The Story Cool! It almost looks as if nature has 'painted' comets on the surface of Mars, using craters as comet cores and dust as streaky tails. Of course, that's just an illusion. As in many areas of Mars, the wind is behind the creation of such fantastic landforms. The natural phenomenon seen here gives this particular surface of Mars a very dynamic, fast-moving, almost luminous 'cosmic personality.' The bright, powdery-looking streaks of dust are in the 'wind shadows' of craters, where dust that settles onto the surface is not as easily scoured away. That's because the wind moves across the land in a particular direction, and a raised surface like the rim of a crater 'protects' dust from being completely blown away on the other side. The raised landforms basically act as a buffer. From the streaks seen above, you can tell the wind was blowing in a northeast to southwest direction. Why are the streaks so bright? Because they contrast with the really dark underlying terrain in this volcanic area of Mars. Syrtis Major is one of the darkest regions on Mars because it is made of basalt. Basalt is typically dark gray or black, and forms when a certain type of molten lava cools. The meaning of the word basalt has been traced back to an ancient Ethiopian word 'basal,' which means 'a rock from which you can obtain iron.' That must have made it a very desired material with ancient Earth civilizations long ago. Basalt is actually one of the most abundant types of rock found on Earth. Most of the volcanic islands in the ocean are made of basalt, including the large shield volcano of Mauna Loa, Hawaii, which is often compared to Martian shield volcanoes. Shield volcanoes don't have high, steep, mountain-like sides, but are instead low and broad humps upon the surface. They're created when highly fluid, molten-basalt flows spread out over wide areas. Over several millennia of basaltic layering upon layering, these volcanoes can reach massive sizes like the ones seen on Mars. You can see the wrinkly texture of dark lava flows (now hard and cool) in the above image beneath the brighter dust.

  14. Volatile Semiochemicals Released from Undamaged Cotton Leaves

    Microsoft Academic Search

    Ursula S. R. Rose; Ara Manukian; Robert R. Heath; James H. Tumlinson

    Cotton plants (Gossypium hirsutum L.), attacked by herbivorous insects release volatile semiochemicals (chemical signals) that at- tract natural enemies of the herbivores to the damaged plants. We found chemical evidence that volatiles are released not only at the damaged site but from the entire cotton plant. lhe release of volatiles was detected from upper, undamaged leaves after 2 to 3

  15. Which Volatility Model for Option Valuation?

    Microsoft Academic Search

    Peter F. Christoffersen; Kris Jacobs

    2002-01-01

    Characterizing asset return dynamics using volatility models is an important part of empirical finance. The existing literature favors some rather complex volatility specifications whose relative performance is usually assessed through their likelihood based on a time-series of asset returns. This paper compares a range of volatility models along a different dimension, using option prices and returns under the risk-neutral as

  16. PORTFOLIO INSURANCE AND VOLATILITY REGIME SWITCHING

    Microsoft Academic Search

    Joel M. Vanden

    2006-01-01

    A new equilibrium model of portfolio insurance is presented in order to study the volatility effects of dynamic insurance strategies. While prior research has focused on the relationship between portfolio insurance and the overall level of market volatility, this article shows that the salient feature of portfolio insurance is volatility regime switching. Regime switching is shown to be a necessary

  17. Excess price volatility and financial innovation

    Microsoft Academic Search

    Alessandro Citanna; Karl Schmedders

    2005-01-01

    Summary. In a three-period finite exchange economy with incomplete financial markets and retrading, we study the effects of the degree of incompleteness and of changes in the financial structure on asset price volatility. In what are essentially no aggregate risk economies, asset price volatility is a sunspot-like phenomenon. If markets are completed by financial innovation, asset price volatility reduction is

  18. Measuring Volatility Clustering in Stock Markets

    Microsoft Academic Search

    Gabjin Oh; Seunghwan Kim; Cheoljun Eom; Taehyuk Kim

    2007-01-01

    We propose a novel method to quantify the clustering behavior in a complex time series and apply it to a high-frequency data of the financial markets. We find that regardless of used data sets, all data exhibits the volatility clustering properties, whereas those which filtered the volatility clustering effect by using the GARCH model reduce volatility clustering significantly. The result

  19. The effects of volatile oils on in vitro potato sprout growth

    Microsoft Academic Search

    H. Baydar; T. Karado?an

    2003-01-01

    Summary  The effects of 10 volatile oils and their main compounds on potato sprout growth were investigated in vitro. Sprout growth\\u000a was inhibited especially by the volatile oils fromOriganum onites, Rosa damascena, Carum carvi, Mentha piperita, Echinophora tuneifolia andCoriandrum sativum. The major compound of volatile oils was carvacrol (78.2%) inO. onites, citronellol (46.7%) inR. damascena, S-(+)-carvone (54.9%) inC. carvi, menthol (44.1%)

  20. Pyrolysis and volatilization of cocaine

    SciTech Connect

    Martin, B.R.; Lue, L.P.; Boni, J.P. (Virginia Commonwealth Univ., Richmond (USA))

    1989-05-01

    The increasing popularity of inhaling cocaine vapor prompted the present study, to determine cocaine's fate during this process. The free base of (3H)cocaine (1 microCi/50 mg) was added to a glass pipe, which was then heated in a furnace to simulate freebasing. Negative pressure was used to draw the vapor through a series of glass wool, ethanol, acidic, and basic traps. Air flow rate and temperature were found to have profound effects on the volatilization and pyrolysis of cocaine. At a temperature of 260 degrees C and a flow rate of 400 mL/min, 37% of the radioactivity remained in the pipe, 39% was found in the glass wool trap, and less than 1% in the remainder of the volatilization apparatus after a 10-min volatilization. Reducing the air flow rate to 100 mL/min reduced the amount of radioactivity collected in the glass wool trap to less than 10% of the starting material and increased the amount that remained in the pipe to 58%. GC/MS analysis of the contents of the glass wool trap after volatilization at 260 degrees C and a flow rate of 400 mL/min revealed that 60% of the cocaine remained intact, while approximately 6 and 2% of the starting material was recovered as benzoic acid and methylecgonidine, respectively. As the temperature was increased to 650 degrees C, benzoic acid and methylecgonidine accounted for 83 and 89% of the starting material, respectively, whereas only 2% of the cocaine remained intact. Quantitation of cocaine in the vapor during the course of volatilization revealed high concentrations during the first two min and low concentrations for the remaining time.

  1. Volatile organic compounds in selected micro-environments

    Microsoft Academic Search

    Andrea Hinwood; Henry Berko; Drew Farrar; Ian Galbally

    2006-01-01

    A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds,

  2. Volatile Components of Sapodilla Fruit (Manilkara achras L.)

    Microsoft Academic Search

    Jorge A. Pino; Rolando Marbot; Juan Aguero

    2003-01-01

    The volatile components of sapodilla fruit, which were isolated by simultaneous steam distillation\\/solvent extraction with diethyl ether, were identified by a combination of retention indices and GC\\/MS. Sixty-nine constituents were identified in the aroma concentrate, from which methanethiol (32.0%), hexadecanoic acid (26.3%), 3-hydroxy-2-butanone (6.8%), ethyl acetate (6.0%) and isoamyl alcohol (5.9%) were found to be the major constituents.

  3. Volatile components of Discaria americana Gillies & Hook (Rhamnaceae)

    Microsoft Academic Search

    Silvana Rodriguez; Ana Paula Murray

    2008-01-01

    The volatile fraction from aerial parts (flowers, stems and leaves) of Discaria americana Gillies & Hook (Rhamnaceae) was obtained by hydrodistillation and the chemical composition of this oil was determined by gas chromatography and gas chromatography–mass spectrometry. The major constituents resulted to be 4-methylphenol (15.5%), eugenol (11%), 3-methylindole (9.7%) and ?-terpineol (6.2%). The essential oil of this plant displayed strong

  4. Laser-induced volatilization and ionization of aerosol particles for their mass spectral analysis in real time

    Microsoft Academic Search

    Mahadeva P. Sinha

    1991-01-01

    A method for the chemical analysis of individual aerosol particles on a real-time basis has been developed. This is accomplished by measuring their mass spectra. In this method, particles are directly introduced in the ion source of the mass spectrograph in the form of a beam. Volatilization and ionization of a particle in an ion source of the mass spectrograph

  5. Clustering High-frequency Stock Data for Trading Volatility Analysis

    Microsoft Academic Search

    Xiao-Wei Ai; Tianming Hu; Xi Li; Hui Xiong

    2010-01-01

    This paper proposes a Realized Trading Volatility (RTV) model for dynamically monitoring anomalous volatility in stock trading. Specifically, the RTV model first extracts the sequences for price volatility, volume volatility, and realized trading volatility. Then, the K-means algorithm is exploited for clustering the summary data of different stocks. The RTV model investigates the joint-volatility between share price and trading volume,

  6. Volatile metal and metalloid species (Pb, Hg, Se) in a European urban atmosphere (Bordeaux, France)

    Microsoft Academic Search

    C. Pecheyran; B. Lalere; O. F. X. Donard

    2000-01-01

    Ambient air measurements of volatile metal and metalloid compounds were conducted in a European urban environment (Bordeaux, France). Air samples were collected with a cryogenic trap and analyzed by low-temperature gas chromatography with ICP\\/MS detection. Indoor and outdoor sites were studied. Tetraalkyl lead compounds (Me{sub 4-n}Et{sub n}Pb, n = 0--4) and elemental mercury were found to be the major volatile

  7. Coumarin-Containing Grass: Volatiles from Sweet Vernalgrass (Anthoxanthum odoratum L.)

    Microsoft Academic Search

    Aldo Tava

    2001-01-01

    Anthoxanthum odoratum, which is a coumarin containing grass, was investigated for its volatile components. The essential oil obtained by steam distillation from the fresh leaves and hay, were analyzed by GC and GC\\/MS. The major volatile component of both leaf and hay oil was coumarin (96.3% and 46.8%, respectively). Aldehydes, alcohols, ketones, phenols, terpenes, hydrocarbons and acids were also identified

  8. Volatile fatty acid fermentation of AFEX-treated newspaper and bagasse by rumen microorganisms

    E-print Network

    Blasig, Jorge Dari?o

    1991-01-01

    VOLATILE FATTY ACID FERMENTATION OF AFEX-TREATED NEWSPAPER AND BAGASSE BY RUMEN MICROORGANISMS A Thesis by JORGE DARIO BLAS IG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillement of the requirements... for the degree of MASTER OF SCIENCE August 1991 Major Subject: Agricultural Engineering VOLATILE FATTY ACID FERMENTATION OF APEX-TREATED NEWSPAPER AND BAGASSE BY RUMEN MICROORGANISMS A Thesis by JORGE DARIO BLASIG Approved as to style and content by...

  9. Volatile fatty acid fermentation of lime-treated biomass by rumen microorganisms

    E-print Network

    Rapier, Charles Robert

    1995-01-01

    VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to the Office of Cnaduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1995 Major Subject: Chemical Engineeriug VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to Texas AkM University in partial fultillment...

  10. Ammonia volatilization and nitrogen transformations in high pH soils used for beef manure disposal 

    E-print Network

    Peters, Robert Edgar

    1972-01-01

    AMMONIA VOLATILIZATION AND NITROGEN TRANSFORMATIONS IN HIGH pH SOILS USED FOR BEEF MANURE DISPOSAL A Thesis by ROBERT EDGAR PETERS Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1972 Major Subject: Agricultural Engineering AMMONIA VOLATILIZATION AND NITROGEN TRANSFORMATIONS IN HIGH pH SOILS USED FOR BEEF MANURE DISPOSAL A Thesis by ROBERT EDGAR PETERS Approved as to style and content...

  11. Fingerprint of volatile flavour constituents and antioxidant activities of teas from Thailand

    Microsoft Academic Search

    Patcharee Pripdeevech; Theeraphan Machan

    2011-01-01

    The volatile flavour components of different teas growing in Thailand were extracted using the simultaneous distillation and extraction (SDE) technique. These volatiles were investigated by GC–MS. At least 54 components representing 76.51–83.32% of all samples were identified. Hotrienol, geraniol and linalool were found to be the major components in Green Oolong tea. Green Assam tea contained linalool, geraniol and ?-terpineol

  12. Characterization of ammonia volatilization from liquid dairy manure

    NASA Astrophysics Data System (ADS)

    Koirala, Kedar

    Emission of gases, odor, and particulate matters from livestock manure is a major concern because of their potential adverse environmental impacts. For example, ammonia in the air has the potential to: negatively affect animal, human health and environment. Mitigation of ammonia emissions from livestock manure to protect animal and human health, and the environment, in general, is thus an important agenda for livestock producers, engineers, and environmental scientists. Proper understanding of the mechanisms or process of its volatilization from manure is the first step towards designing or formulating appropriate emissions mitigation strategies. This research investigated the effects of suspended solids, anaerobic digestion, and ionic strength on the ammonia (NH3) volatilization mechanism from liquid dairy manure. Experiments were conducted to: (i) assess the role of suspended solids characteristics on ammonia volatilization, (ii) evaluate the impacts of anaerobic digestion on the process governing NH 3 volatilization, and (iii) delineate the influences of suspended solids (SS) and ionic strength (IS) on the ammonia volatilization process from dairy manure. Two key parameters (the ammonia dissociation and the overall mass transfer coefficient (KoL)) that govern ammonia volatilization were evaluated to achieve these objectives. The physical and chemical properties of manure were also evaluated to further elucidate the respective processes. The suspended solids ammoniacal nitrogen adsorption properties did not significantly affect either the ammonium dissociation or the K oL; suggesting that the characteristics of manure suspended solids did not play a significant role in ammonia volatilization from liquid dairy manure. The dissociation of ammonium in anaerobically digested (AD) manure was significantly higher than in the undigested (UD) manure. However, KoL was less in AD manure than in UD manure, while an increase in total ammoniacal nitrogen (TAN) was observed after anaerobic digestion of manure. Overall, increases in ammonium dissociation and TAN after anaerobic digestion indicated higher potential of NH3 volatilization in AD manure. Significant increases in SS concentration and IS were necessary to influence the ammonium dissociation in dairy manure. For all practical purposes, therefore, the individual effects of suspended solids and ionic strength were deemed negligible within the normal ranges of liquid dairy manure characteristics.

  13. Volatile constituents in a wood pyrolysis oil 

    E-print Network

    Lin, Shih-Chien

    1978-01-01

    was determined on six me als. Acetic and formic acids were found to be the major corrosive agents. !Vine frac ions of pyrolysis oil obtained by vacuum fractional d still ation were classified on a 0$-1-38/H PO / 3 4 SP1210, 80/100 chromosorb G. C. column. Ph...-nolic sub- sta&'&c. s such as phenol, guaiacol, m, p-cresol, and as yet unidentified phenol s with NW 138 and NW 152 wsre the major co&mponents. The contents of 36 component in the nine frac- tions and tI&e trap were calculated. AC KN OWL EDG MENTS I...

  14. Syrtis Major

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 18 May 2004 This image of Syrtis Major was acquired August 20, 2002, during northern spring.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 12.8, Longitude 79.5 East (280.5 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Penicillium expansum volatiles reduce pine weevil attraction to host plants.

    PubMed

    Azeem, Muhammad; Rajarao, Gunaratna Kuttuva; Nordenhem, Henrik; Nordlander, Göran; Borg-Karlson, Anna Karin

    2013-01-01

    The pine weevil Hylobius abietis (L.) is a severe pest of conifer seedlings in reforested areas of Europe and Asia. To identify minimally toxic and ecologically sustainable compounds for protecting newly planted seedlings, we evaluated the volatile metabolites produced by microbes isolated from H. abietis feces and frass. Female weevils deposit feces and chew bark at oviposition sites, presumably thus protecting eggs from feeding conspecifics. We hypothesize that microbes present in feces/frass are responsible for producing compounds that deter weevils. Here, we describe the isolation of a fungus from feces and frass of H. abietis and the biological activity of its volatile metabolites. The fungus was identified by morphological and molecular methods as Penicillium expansum Link ex. Thom. It was cultured on sterilized H. abietis frass medium in glass flasks, and volatiles were collected by SPME and analyzed by GC-MS. The major volatiles of the fungus were styrene and 3-methylanisole. The nutrient conditions for maximum production of styrene and 3-methylanisole were examined. Large quantities of styrene were produced when the fungus was cultured on grated pine bark with yeast extract. In a multi-choice arena test, styrene significantly reduced male and female pine weevils' attraction to cut pieces of Scots pine twigs, whereas 3-methylanisole only reduced male weevil attraction to pine twigs. These studies suggest that metabolites produced by microbes may be useful as compounds for controlling insects, and could serve as sustainable alternatives to synthetic insecticides. PMID:23297108

  16. Arbitrage and Volatility in Chinese Stock's Markets

    NASA Astrophysics Data System (ADS)

    Lu, Shu Quan; Ito, Takao; Zhang, Jianbo

    From the point of view of no-arbitrage pricing, what matters is how much volatility the stock has, for volatility measures the amount of profit that can be made from shorting stocks and purchasing options. With the short-sales constraints or in the absence of options, however, high volatility is likely to mean arbitrage from stock market. As emerging stock markets for China, investors are increasingly concerned about volatilities of Chinese two stock markets. We estimate volatility's models for Chinese stock markets' indexes using Markov chain Monte Carlo (MCMC) method and GARCH. We find that estimated values of volatility parameters are very high for all data frequencies. It suggests that stock returns are extremely volatile even at long term intervals in Chinese markets. Furthermore, this result could be considered that there seems to be arbitrage opportunities in Chinese stock markets.

  17. Direct injection ion chromatography for the control of chlorinated drinking water: simultaneous estimation of nine haloacetic acids and quantitation of bromate, chlorite and chlorate along with the major inorganic anions.

    PubMed

    Garcia-Villanova, Rafael J; Raposo Funcia, César; Oliveira Dantas Leite, M Vilani; Toruño Fonseca, Ivania M; Espinosa Nieto, Miguel; Espuelas India, Javier

    2014-09-01

    Most methods for the analysis of haloacetic acids published in recent years are based on ion chromatography with direct injection, employing a gradient elution with potassium hydroxide (KOH). This work reports the exploration of an alternative eluent, a buffer of sodium carbonate/sodium hydrogen carbonate, aimed at the simultaneous analysis of nine haloacetic acids along with bromate, chlorite and chlorate. The alternative of both a less alkaline eluent and a lower temperature of operation may prevent the partial decomposition of some of the haloacetic acids during the analytical process, especially the more vulnerable brominated ones. Gradient elution at temperature of 7 °C yielded the best results, with an acceptable separation of 17 analytes (which includes the major natural inorganic anions) and a good linearity. Precision ranges from 0.3 to 23.4 (% V.C.), and detection limits are within units of ?g L?¹, except for tribromoacetic acid - somewhat high in comparison with those of the official methods. Nonetheless, with the basic instrumentation setup herein described, this method may be suitable for monitoring when the drinking water treatments are to be optimized. This is especially interesting for small communities or for developing/developed countries in which regulations on disinfection by-products others than trihalomethanes are being addressed. PMID:25252348

  18. Phosphorus as a lunar volatile

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew A.

    2015-07-01

    Phosphorus is an important minor element on the Moon. It is moderately volatile and is found as both phosphates and phosphides in lunar material. The phosphides, such as schreibersite, are common to impact breccias at all Apollo sites. The origin of this schreibersite has been proposed to be a meteoritic contaminant, or alternatively produced in situ by reduction on the lunar surface. I propose that schreibersite and other siderophilic P phases have an origin from impact volatilization of phosphates at the lunar oxygen fugacity, followed by reaction of P gases with metal to form metal phosphides. This pathway is broadly consistent with the composition and structure of metal grains, as well as the native oxygen fugacity of the lunar surface. Additionally, this pathway suggests schreibersite is widespread across the lunar surface and likely on other planetary bodies, and hence may serve as a good P source for in situ resource utilization.

  19. The volatile composition of comets

    NASA Technical Reports Server (NTRS)

    Weaver, H. A.

    1988-01-01

    Comets may be our best probes of the physical and chemical conditions in the outer regions of the solar nebula during that crucial period when the planets formed. The volatile composition of cometary nuclei can be used to decide whether comets are the product of a condensation sequence similar to that invoked to explain the compositions of the planets and asteroids, or if comets are simply agglomerations of interstellar grains which have been insignificantly modified by the events that shaped the other bodies in the solar system. Although cometary nuclei are not generally accessible to observation, observations of cometary comae can illuminate at least some of the mysteries of the nuclei provided one has a detailed knowledge of the excitation conditions in the coma and also has access to basic atomic and molecular data on the many species present in comets. Examined here is the status of our knowledge of the volatile composition of cometary nuclei and how these data are obtained.

  20. COMPARISON OF EMISSION PROFILES FOR VOLATILE ORGANIC COMPOUNDS FROM COTTON AND POLYPROPYLENE-BASED TARP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A high electric field, radio-frequency ion mobility analyzer (RF-IMS) was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, esters, ethers, pheromes, and other chemical attractants for insects. The detector was equip...

  1. Volatilization from PCA steel alloy

    SciTech Connect

    Hagrman, D.L.; Smolik, G.R.; McCarthy, K.A.; Petti, D.A. [Lockheed Martin Idaho Technologies Company, Idaho Falls, ID (United States)

    1996-12-31

    The mobilizations of key components from Primary Candidate Alloy (PCA) steel alloy have been measured with laboratory-scale experiments. The experiments indicate most of the mobilization from PCA steel is due to oxide formation and spalling but that the spalled particles are large enough to settle rapidly. Based on the experiments, models for the volatilization of iron, manganese, and cobalt from PCA steel in steam and molybdenum from PCA steel in air have been derived. 6 refs., 3 figs.

  2. Photodegradation and volatility of pesticides

    Microsoft Academic Search

    Thomas Kromer; Holger Ophoff; Andreas Stork; Fritz Fiihr

    2004-01-01

    Background and Objectives  Among the factors affecting the environmental fate of surface-applied pesticides several biological as well as abiotic factors,\\u000a such as volatilization and photochemical transformations are of particular interest. Whereas reliable measurement methods\\u000a and models for estimating direct photodegradation are already available for the compartments of water and atmosphere and individual\\u000a subprocesses have already been described in detail, there is

  3. Flavour compounds in tomato fruits: identification of loci and potential pathways affecting volatile composition

    PubMed Central

    Mathieu, Sandrine; Cin, Valeriano Dal; Fei, Zhangjun; Li, Hua; Bliss, Peter; Taylor, Mark G.; Klee, Harry J.; Tieman, Denise M.

    2009-01-01

    The unique flavour of a tomato fruit is the sum of a complex interaction among sugars, acids, and a large set of volatile compounds. While it is generally acknowledged that the flavour of commercially produced tomatoes is inferior, the biochemical and genetic complexity of the trait has made breeding for improved flavour extremely difficult. The volatiles, in particular, present a major challenge for flavour improvement, being generated from a diverse set of lipid, amino acid, and carotenoid precursors. Very few genes controlling their biosynthesis have been identified. New quantitative trait loci (QTLs) that affect the volatile emissions of red-ripe fruits are described here. A population of introgression lines derived from a cross between the cultivated tomato Solanum lycopersicum and its wild relative, S. habrochaites, was characterized over multiple seasons and locations. A total of 30 QTLs affecting the emission of one or more volatiles were mapped. The data from this mapping project, combined with previously collected data on an IL population derived from a cross between S. lycopersicum and S. pennellii populations, were used to construct a correlational database. A metabolite tree derived from these data provides new insights into the pathways for the synthesis of several of these volatiles. One QTL is a novel locus affecting fruit carotenoid content on chromosome 2. Volatile emissions from this and other lines indicate that the linear and cyclic apocarotenoid volatiles are probably derived from separate carotenoid pools. PMID:19088332

  4. Contribution of volatiles to the antifungal effect of Lactobacillus paracasei in defined medium and yogurt.

    PubMed

    Aunsbjerg, S D; Honoré, A H; Marcussen, J; Ebrahimi, P; Vogensen, F K; Benfeldt, C; Skov, T; Knøchel, S

    2015-02-01

    Lactic acid bacteria with antifungal properties can be used to control spoilage of food and feed. Previously, most of the identified metabolites have been isolated from cell-free fermentate of lactic acid bacteria with methods suboptimal for detecting possible contribution from volatiles to the antifungal activity. The role of volatile compounds in the antifungal activity of Lactobacillus paracasei DGCC 2132 in a chemically defined interaction medium (CDIM) and yogurt was therefore investigated with a sampling technique minimizing volatile loss. Diacetyl was identified as the major volatile produced by L. paracasei DGCC 2132 in CDIM. When the strain was added to a yogurt medium diacetyl as well as other volatiles also increased but the metabolome was more complex. Removal of L. paracasei DGCC 2132 cells from CDIM fermentate resulted in loss of both volatiles, including diacetyl, and the antifungal activity towards two strains of Penicillium spp. When adding diacetyl to CDIM or yogurt without L. paracasei DGCC 2132, marked inhibition was observed. Besides diacetyl, the antifungal properties of acetoin were examined, but no antifungal activity was observed. Overall, the results demonstrate the contribution of diacetyl in the antifungal effect of L. paracasei DGCC 2132 and indicate that the importance of volatiles may have been previously underestimated. PMID:25461608

  5. Dynamic modeling of biodegradation and volatilization of hazardous aromatic substances in aerobic bioreactor.

    PubMed

    Mozo, I; Lesage, G; Yin, J; Bessiere, Y; Barna, L; Sperandio, M

    2012-10-15

    The aerobic biological process is one of the best technologies available for removing hazardous organic substances from industrial wastewaters. But in the case of volatile organic compounds (benzene, toluene, ethylbenzene, p-xylene, naphthalene), volatilization can contribute significantly to their removal from the liquid phase. One major issue is to predict the competition between volatilization and biodegradation in biological process depending on the target molecule. The aim of this study was to develop an integrated dynamic model to evaluate the influence of operating conditions, kinetic parameters and physical properties of the molecule on the main pathways (biodegradation and volatilization) for the removal of Volatile Organic Compounds (VOC). After a comparison with experimental data, sensitivity studies were carried out in order to optimize the aerated biological process. Acclimatized biomass growth is limited by volatilization, which reduces the bioavailability of the substrate. Moreover, the amount of biodegraded substrate is directly proportional to the amount of active biomass stabilized in the process. Model outputs predict that biodegradation is enhanced at high SRT for molecules with low H and with a high growth rate population. Air flow rate should be optimized to meet the oxygen demand and to minimize VOC stripping. Finally, the feeding strategy was found to be the most influential operating parameter that should be adjusted in order to enhance VOC biodegradation and to limit their volatilization in sequencing batch reactors (SBR). PMID:22877879

  6. Volatile constituents from Cinnamomum zeylanicum fruit stalks and their antioxidant activities.

    PubMed

    Jayaprakasha, Guddadarangavvanahally K; Jagan Mohan Rao, Lingamallu; Sakariah, Kunnumpurath K

    2003-07-16

    Cinnamomum zeylanicum Blume is an important spice and aromatic crop having wide applications in flavoring, perfumery, beverages, and medicines. The steam-distilled volatile oil from cinnamon fruit stalks was analyzed with GC and GC-MS. It showed the presence of hydrocarbons (44.7%) and oxygenated compounds (52.6%). Twenty-seven compounds constituting ca. 95.98% of the volatile oil were characterized. (E)-Cinnamyl acetate (36.59%) and (E)-caryophyllene (22.36%) are found to be major compounds. The volatile oil was screened for its potential as an antioxidant by using in vitro models, such as the beta-carotene-linoleate and phosphomolybdenum complex method. The volatile oil showed 55.94% and 66.9% antioxidant activity at 100 and 200 ppm concentration, respectively. Also, the volatile oil showed good antioxidant capacity, using the formation of the phosphomolybdenum complex. A comparison of the chemical composition of the volatile oil was made with that of buds, flowers, and fruits. This is the first report on the chemical composition of volatile oil of the fruit stalks of this species and its antioxidant activity. PMID:12848508

  7. Improved Ambient Pressure Pyroelectric Ion Source

    NASA Technical Reports Server (NTRS)

    Beegle, Luther W.; Kim, Hugh I.; Kanik, Isik; Ryu, Ernest K.; Beckett, Brett

    2011-01-01

    The detection of volatile vapors of unknown species in a complex field environment is required in many different applications. Mass spectroscopic techniques require subsystems including an ionization unit and sample transport mechanism. All of these subsystems must have low mass, small volume, low power, and be rugged. A volatile molecular detector, an ambient pressure pyroelectric ion source (APPIS) that met these requirements, was recently reported by Caltech researchers to be used in in situ environments.

  8. Fatty Acid Composition and Volatile Constituents of Protaetia brevitarsis Larvae

    PubMed Central

    Yeo, Hyelim; Youn, Kumju; Kim, Minji; Yun, Eun-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

    2013-01-01

    A total of 48 different volatile oils were identified form P. brevitarsis larvae by gas chromatography/mass spectrometry (GC/MS). Acids (48.67%) were detected as the major group in P. brevitarsis larvae comprising the largest proportion of the volatile compounds, followed by esters (19.84%), hydrocarbons (18.90%), alcohols (8.37%), miscellaneous (1.71%), aldehydes (1.35%) and terpenes (1.16%). The major volatile constituents were 9-hexadecenoic acid (16.75%), 6-octadecenoic acid (14.88%) and n-hexadecanoic acid (11.06%). The composition of fatty acid was also determined by GC analysis and 16 fatty acids were identified. The predominant fatty acids were oleic acid (C18:1, 64.24%) followed by palmitic acid (C16:0, 15.89%), palmitoleic acid (C16:1, 10.43%) and linoleic acid (C18:2, 4.69%) constituting more than 95% of total fatty acids. The distinguished characteristic of the fatty acid profile of P. brevitarsis larvae was the high proportion of unsaturated fatty acid (80.54% of total fatty acids) versus saturated fatty acids (19.46% of total fatty acids). Furthermore, small but significant amounts of linoleic, linolenic and ?-linolenic acids bestow P. brevitarsis larvae with considerable nutritional value. The novel findings of the present study provide a scientific basis for the comprehensive utilization of the insect as a nutritionally promising food source and a possibility for more effective utilization. PMID:24471125

  9. Production of volatile organic compounds by mycobacteria.

    PubMed

    McNerney, Ruth; Mallard, Kim; Okolo, Phyllis Ifeoma; Turner, Claire

    2012-03-01

    The need for improved rapid diagnostic tests for tuberculosis disease has prompted interest in the volatile organic compounds (VOCs) emitted by Mycobacterium tuberculosis complex bacteria. We have investigated VOCs emitted by Mycobacterium bovis BCG grown on Lowenstein-Jensen media using selected ion flow tube mass spectrometry and thermal desorption-gas chromatography-mass spectrometry. Compounds observed included dimethyl sulphide, 3-methyl-1-butanol, 2-methyl-1-propanol, butanone, 2-methyl-1-butanol, methyl 2-methylbutanoate, 2-phenylethanol and hydrogen sulphide. Changes in levels of acetaldehyde, methanol and ammonia were also observed. The compounds identified are not unique to M. bovis BCG, and further studies are needed to validate their diagnostic value. Investigations using an ultra-rapid gas chromatograph with a surface acoustic wave sensor (zNose) demonstrated the presence of 2-phenylethanol (PEA) in the headspace of cultures of M. bovis BCG and Mycobacterium smegmatis, when grown on Lowenstein-Jensen supplemented with glycerol. PEA is a reversible inhibitor of DNA synthesis. It is used during selective isolation of gram-positive bacteria and may also be used to inhibit mycobacterial growth. PEA production was observed to be dependent on growth of mycobacteria. Further study is required to elucidate the metabolic pathways involved and assess whether this compound is produced during in vivo growth of mycobacteria. PMID:22224870

  10. Citrus Leaf Volatiles as Affected by Developmental Stage and Genetic Type

    PubMed Central

    Azam, Muhammad; Jiang, Qian; Zhang, Bo; Xu, Changjie; Chen, Kunsong

    2013-01-01

    Major volatiles from young and mature leaves of different citrus types were analyzed by headspace-solid phase microextraction (HS-SPME)-GC-MS. A total of 123 components were identified form nine citrus cultivars, including nine aldehydes, 19 monoterpene hydrocarbons, 27 oxygenated monoterpenes, 43 sesquiterpene hydrocarbons, eight oxygenated sesquiterpenes, two ketones, six esters and nine miscellaneous. Young leaves produced higher amounts of volatiles than mature leaves in most cultivars. The percentage of aldehyde and monoterpene hydrocarbons increased, whilst oxygenated monoterpenes and sesquiterpenes compounds decreased during leaf development. Linalool was the most abundant compound in young leaves, whereas limonene was the chief component in mature ones. Notably, linalool content decreased, while limonene increased, during leaf development in most cultivars. Leaf volatiles were also affected by genetic types. A most abundant volatile in one or several genotypes can be absent in another one(s), such as limonene in young leaves of lemon vs. Satsuma mandarin and ?-terpinene in mature leaves of three genotypes vs. the other four. Compositional data was subjected to multivariate statistical analysis, and variations in leaf volatiles were identified and clustered into six groups. This research determining the relationship between production of major volatiles from different citrus varieties and leaf stages could be of use for industrial and culinary purposes. PMID:23994837

  11. Floral volatiles: from biosynthesis to function.

    PubMed

    Muhlemann, Joëlle K; Klempien, Antje; Dudareva, Natalia

    2014-08-01

    Floral volatiles have attracted humans' attention since antiquity and have since then permeated many aspects of our lives. Indeed, they are heavily used in perfumes, cosmetics, flavourings and medicinal applications. However, their primary function is to mediate ecological interactions between flowers and a diverse array of visitors, including pollinators, florivores and pathogens. As such, they ultimately ensure the plants' reproductive and evolutionary success. To date, over 1700 floral volatile organic compounds (VOCs) have been identified. Interestingly, they are derived from only a few biochemical networks, which include the terpenoid, phenylpropanoid/benzenoid and fatty acid biosynthetic pathways. These pathways are intricately regulated by endogenous and external factors to enable spatially and temporally controlled emission of floral volatiles, thereby fine-tuning the ecological interactions facilitated by floral volatiles. In this review, we will focus on describing the biosynthetic pathways leading to floral VOCs, the regulation of floral volatile emission, as well as biological functions of emitted volatiles. PMID:24588567

  12. Low-Volatility Compound Evaporation from the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Koss, A.; De Gouw, J. A.; Warneke, C.

    2011-12-01

    The Deepwater Horizon (DWH) oil spill in April-August 2010 provided an unusual opportunity to study secondary organic aerosol (SOA) formation on a large scale. Chemicals with differing volatility, evaporating at different rates, were spatially separated and released to the atmosphere at different locations. The resulting distribution of vapor and aerosol phase organic compounds were measured during research flights of the NOAA WP-3D aircraft over the Gulf in June 2010 (de Gouw et al., 2011). Known volatile SOA precursors (C8 to C11 hydrocarbons) were measured in a thin plume downwind of DWH. SOA was measured in a much wider plume, indicating contributions from less volatile compounds evaporating further from the source. Estimates of semi- and intermediate- volatile compound evaporation rates from the oil spill have been improved using a component-wise first-order kinetics model in which the evaporation rate of a compound is proportional to both its vapor pressure and mole fraction. The model was validated through proton-transfer-reaction ion-trap mass spectrometer measurements of evaporating South Louisiana crude oil and calibration mixtures of aromatic compounds. These new evaporation rate estimates highlight several concepts important to a revised interpretation of the June 2010 aerosol measurements. The rates of evaporation (and thus atmospheric concentrations) of low-volatility compounds did not necessarily reflect surface distribution. Low volatility compounds reached peak evaporation rates at appreciable distances from the source, and the area from which significant amounts of chemical were emitted was larger than previously thought.

  13. Birds exploit herbivore-induced plant volatiles to locate herbivorous prey.

    PubMed

    Amo, Luisa; Jansen, Jeroen J; van Dam, Nicole M; Dicke, Marcel; Visser, Marcel E

    2013-11-01

    Arthropod herbivory induces plant volatiles that can be used by natural enemies of the herbivores to find their prey. This has been studied mainly for arthropods that prey upon or parasitise herbivorous arthropods but rarely for insectivorous birds, one of the main groups of predators of herbivorous insects such as lepidopteran larvae. Here, we show that great tits (Parus major) discriminate between caterpillar-infested and uninfested trees. Birds were attracted to infested trees, even when they could not see the larvae or their feeding damage. We furthermore show that infested and uninfested trees differ in volatile emissions and visual characteristics. Finally, we show, for the first time, that birds smell which tree is infested with their prey based on differences in volatile profiles emitted by infested and uninfested trees. Volatiles emitted by plants in response to herbivory by lepidopteran larvae thus not only attract predatory insects but also vertebrate predators. PMID:24103093

  14. Volatility and composition of aerosols in tropical stratosphere and TTL over Biak, Indonesia

    NASA Astrophysics Data System (ADS)

    Hayashi, M.; Shibata, T.; Hara, K.; Hasebe, F.

    2014-12-01

    Number concentration and volatility of aerosols in the Tropical Tropopause Layer (TTL) over Biak (1.2 oS, 136.1 oE) were observed using balloon-borne dual optical particle counters (OPC) in January 2011, 2012, and 2013. One OPC observed number concentration of ambient aerosols and another OPC had an inlet with a thermo denuder, whose temperature were set at 100 to 300 oC, in order to observe volatility. The results suggest that major composition of aerosol change with altitude, from sulfate in upper troposphere to sulfuric acid in stratosphere through TTL region. The ratios of number concentrations of un-volatile aerosol, to those of ambient aerosol in sub-micrometer size range are few percent in stratosphere and several percent in TTL. In addition, un-volatile aerosol concentrations were similar to the concentration of ice particle in sub-visible cirrus.

  15. Role of an esterase in flavor volatile variation within the tomato clade

    PubMed Central

    Goulet, Charles; Mageroy, Melissa H.; Lam, Nghi B.; Floystad, Abbye; Tieman, Denise M.; Klee, Harry J.

    2012-01-01

    Tomato flavor is dependent upon a complex mixture of volatiles including multiple acetate esters. Red-fruited species of the tomato clade accumulate a relatively low content of acetate esters in comparison with the green-fruited species. We show that the difference in volatile ester content between the red- and green-fruited species is associated with insertion of a retrotransposon adjacent to the most enzymatically active member of a family of esterases. This insertion causes higher expression of the esterase, resulting in the reduced levels of multiple esters that are negatively correlated with human preferences for tomato. The insertion was evolutionarily fixed in the red-fruited species, suggesting that high expression of the esterase and consequent low ester content may provide an adaptive advantage in the ancestor of the red-fruited species. These results illustrate at a molecular level how closely related species exhibit major differences in volatile production by altering a volatile-associated catabolic activity. PMID:23112200

  16. Magmatic volatiles in explosive rhyolitic eruptions

    Microsoft Academic Search

    J. C. Eichelberger; H. R. Westrich

    1981-01-01

    Obsidian clasts in rhyolitic tephra deposits preserve preeruption magmatic volatile contents, providing a direct means for determining the volatile content of explosively erupted magmas. Small to moderate volume Plinian eruptions (10⁻³ to 10⁻¹ km³) appear to be driven by 0.5--1.0 wt.% volatiles, consisting dominantly of HâO with minor COâ. Analysis of obsidian from eruptive sequences consisting of tephra and flows

  17. Impact of microorganism on polonium volatilization

    Microsoft Academic Search

    N. Momoshima; A. Fukuda; A. Ishida; C. Yoshinaga

    2007-01-01

    Volatilization of polonium by microorganisms, Chromobacterium violaceum, Escherichia coli and Bacillus subtilis was examined for pure cultures in LB medium at 30 °C, showing relative Po emission intensity 100, 10 and 1, respectively.\\u000a Chromobacterium violaceum pre-cultured in LB medium without Po and suspended in water with Po showed high Po volatilization in spite of poor nutriment\\u000a condition. Antibiotics inhibit volatilization

  18. Silicon Nanowires for Non-Volatile Memory

    E-print Network

    Silicon Nanowires for Non-Volatile Memory P R O J E C T L E A D E R : Curt A. Richter (NIST) C O L approaches for silicon nanowire non-volatile memory. K E Y A C C O M P L I S H M E N T S Fabricated novel non-volatile memory cells with silicon nanowire channels and Al2 O3 /HfO2 /SiO2 gate dielectric storage stacks

  19. Conference on Deep Earth and Planetary Volatiles

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The following topics are covered in the presented papers: (1) rare gases systematics and mantle structure; (2) volatiles in the earth; (3) impact degassing of water and noble gases from silicates; (4) D/H ratios and H2O contents of mantle-derived amphibole megacrysts; (5) thermochemistry of dense hydrous magnesium silicates; (6) modeling of the effect of water on mantle rheology; (7) noble gas isotopes and halogens in volatile-rich inclusions in diamonds; (8) origin and loss of the volatiles of the terrestrial planets; (9) structure and the stability of hydrous minerals at high pressure; (10) recycling of volatiles at subduction zones and various other topics.

  20. [Solidification of volatile oil with graphene oxide].

    PubMed

    Yan, Hong-Mei; Jia, Xiao-Bin; Zhang, Zhen-Hai; Sun, E; Xu, Yi-Hao

    2015-02-01

    To evaluate the properties of solidifying volatile oil with graphene oxide, clove oil and zedoary turmeric oil were solidified by graphene oxide. The amount of graphene oxide was optimized with the eugenol yield and curcumol yield as criteria. Curing powder was characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The effects of graphene oxide on dissolution in vitro and thermal stability of active components were studied. The optimum solidification ratio of graphene oxide to volatile oil was 1:1. Dissolution rate of active components had rare influence while their thermal stability improved after volatile oil was solidified. Solidifying herbal volatile oil with graphene oxide deserves further study. PMID:25975033

  1. Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress

    PubMed Central

    Colville, Louise

    2012-01-01

    The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography–mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670

  2. Non-volatile, solid state bistable electrical switch

    NASA Technical Reports Server (NTRS)

    Williams, Roger M. (inventor)

    1994-01-01

    A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state. Application of the electrical potential in the opposite direction causes reverse current flow which de-intercalates the bistable logic switching element and produces a high resistance logic state.

  3. Volatile components in defensive spray of the hog-nosed skunk, Conepatus mesoleucus

    Microsoft Academic Search

    William F. Wood; Christoph O. Fisher; Gary A. Graham

    1993-01-01

    GC-MS analysis of the anal sac secretion from the hog-nosed skunk,Conepatus mesoleucus, showed two major volatile components, (E)-2-butene-1-thiol and (E)-S-2-butenyl thioacetate. Minor volatile components identified from this secretion were phenylmethanethiol, 2-methylquinoline, 2-quinolinemethanethiol, and bis[(E)-2-butenyl] disulfide. 3-Methyl-1-butanethiol, a major component in the defensive spray of the striped skunk,Mephitis mephitis, and the spotted skunk,Spilogale putorius, was absent from this secretion.

  4. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  5. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Laramie, WY); Sorini-Wong, Susan S. (Laramie, WY)

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  6. On-Plant Volatile Analysis Utilizing Solid-Phase Microextraction and a New Volatile Collection Technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile emission of plants is typically measured by removal of the plant-part, transportation to a laboratory, and subsequent volatile analyses via a number of accepted methodologies. Studies performed by our laboratory have shown the volatile emission of removed plant parts are essentially identic...

  7. Separating ambiguity and volatility in cash flow simulation based volatility estimation

    Microsoft Academic Search

    Tero Haahtela

    Volatility is a significant parameter both in financial and real options valuation. However, in the case of several real option projects there is no historical data available. In such cases, one alternative is to use Monte Carlo simulation on projects' cash flows for volatility estimation. An important issue that has not been taken into account with most of these volatility

  8. IN-HOUSE REFORMULATION AND EVALUATION OF MAJOR MANUFACTURER'S VEHICLE REFINISHING COATINGS

    EPA Science Inventory

    The goal is to develop high quality vehicle refinishing paint formulations that contain much less toxi and volatile solvents than the major manufacturer's Federal compliant and California complaint coatings. The reformulated coatings being developed will maintain or improve upo...

  9. SELECTION GUIDE FOR VOLATILIZATION TECHNOLOGIES FOR WATER TREATMENT

    EPA Science Inventory

    The guide presents a methodology for evaluating applicability of volatilization technologies for removing volatile organics from water. The volatilization technologies assessed in the study include: surface sprayers, surface aerators, bubble columns, cooling towers, steam strippe...

  10. PSYCHOLOGY MAJORS --1 PSYCHOLOGY MAJORS --2

    E-print Network

    Sanders, Matthew

    PSYCHOLOGY MAJORS -- 1 #12;PSYCHOLOGY MAJORS -- 2 Handbook for Undergraduate Psychology Majors......................................................................................................................................2 A. Psychology Program Goals and Purpose B. Declaration of Major C. History of Marquette University D. Facilities E. Graduate Program in Clinical Psychology 2. Department Faculty and Staff

  11. Fall 2012 Majors Counts Undergraduate # of Majors Degree Majors Total

    E-print Network

    Su, Xiao

    /Pictorial Arts 15 BFA Art/Spatial Arts 49 BA Art/Art History and Visual Culture 51 BA Art Design 201 BS Industrial Design 77 BFA Graphic Design 168 BFA Interior Design 453 BA Art/Design Studies English 408 BAFall 2012 Majors Counts Undergraduate # of Majors Degree Majors Total 164 BA Art/Studio Practice

  12. Ambient orchard volatiles from California almonds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The volatile emissions of various plant parts of almonds have been studied via various techniques in the past. These analyses have typically been performed on single cultivars and hence may not be representative of the volatiles found in an entire almond orchard. Recent reports suggest some almond v...

  13. Noise trading and stock market volatility

    Microsoft Academic Search

    Rahul Verma; Priti Verma

    2007-01-01

    We investigate the relative effects of fundamental and noise trading on the formation of conditional volatility. We find significant positive (negative) effects of investor sentiments on stock returns (volatilities) for both individual and institutional investors. There are greater positive effects of rational sentiments on stock returns than irrational sentiments. Conversely, there are significant (insignificant) negative effects of irrational (rational) sentiments

  14. INSTITUTIONAL INVESTORS AND STOCK MARKET VOLATILITY*

    E-print Network

    Stanley, H. Eugene

    stock. Since his desired trading volume is then a significant proportion of daily turnover, heINSTITUTIONAL INVESTORS AND STOCK MARKET VOLATILITY* XAVIER GABAIX PARAMESWARAN GOPIKRISHNAN VASILIKI PLEROU H. EUGENE STANLEY We present a theory of excess stock market volatility, in which market

  15. ON THE VOLATILITY OF SOME POLONIUM COMPOUNDS

    Microsoft Academic Search

    H Mabuchi

    1963-01-01

    The volatility of thirteen polonium compounds that are extractable with ; organic solvents was investigated. The reresult of heating tests showed that all ; compounds resulting from the interaction of polonium with chelating agents ; volatilize beiow 200 deg C\\/l atm. (auth);

  16. VOLATILIZED LUBRICANT EMISSIONS FROM STEEL ROLLING OPERATIONS

    EPA Science Inventory

    The report gives results of a study of the volatilization of lubricants used in steel rolling. Data from nine steel mills were used to: define the volatilized portion of lubricants used in rolling; and prepare total oil, grease, and hydraulic material balances for actual and typi...

  17. Volatility clustering in monthly stock returns

    Microsoft Academic Search

    Ben Jacobsen; Dennis Dannenburg

    2003-01-01

    We investigate volatility clustering using a modeling approach based on the temporal aggregation results for generalized autoregressive conditional heteroscedasticity (GARCH) models in Drost and Nijman [Econometrica 61 (1993) 909]. Our findings highlight that volatility clustering, contrary to widespread belief, is not only present in high-frequency financial data. Monthly data also exhibit significant serial dependence in the second moments. We show

  18. Oil price volatility and the macroeconomy

    Microsoft Academic Search

    J. Peter Ferderer

    1996-01-01

    Recent theoretical work suggests that oil price shocks may have an adverse impact on the macroeconomy, not only because they increase the level of oil prices, but also because they raise oil price volatility. This paper provides empirical support for this proposition by showing that oil price volatility, measured by monthly standard deviations of daily oil prices, helps to forecast

  19. Inflation, Oil Price Volatility and Monetary Policy

    Microsoft Academic Search

    Paul Castillo; Carlos Montoro; Vicente. Tuesta

    2010-01-01

    In a fully micro-founded New Keynesian framework, we characterize analytically the relation between average inflation and oil price volatility by solving the rational expectations equilibrium of the model up to second order of accuracy. Higher oil price volatility induces higher levels of average inflation. We also show that when oil has low substitutability and the central bank responds to output

  20. The Time Varying Volatility of Macroeconomic Fluctuations

    Microsoft Academic Search

    Alejandro Justiniano; GIORGIO E. PRIMICERI

    2006-01-01

    In this paper we investigate the sources of the important shifts in the volatility of U.S. macroeconomic variables in the postwar period. To this end, we propose the estimation of DSGE models allowing for time variation in the volatility of the structural innovations. We apply our estimation strategy to a large-scale model of the business cycle and find that investment

  1. Volatility of the diglycolamine salt of dicamba 

    E-print Network

    Sciumbato, Audy Shane

    1999-01-01

    from 4x10?¹ to 1x10?? times the normal use rates. Injury was recorded at 1,5,9 and 14 DAT using a categorical injury rating scale. Herbicide volatility data was then obtained in the greenhouse using volatility chambers that exposed cotton and soybean...

  2. Kinetics of volatile extraction from carbonaceous chondrites: Dehydration of talc

    NASA Technical Reports Server (NTRS)

    Bose, Kunal; Ganguly, Jibamitra

    1991-01-01

    Carbonaceous chondrites are believed to be the primary constituents of near-Earth asteroids and Phobos and Deimos, and are potential resources of fuels that may be exploited for future planetary missions. Calculations of equilibrium phase relations suggest that talc (Ta) and antigorite (Ant) are likely to be the major hydrous phases in the C1 and C2 meteorites (Ganguly and Saxena, 1989), which constitute the most volatile rich classes of carbonaceous chondrites. The dehydration kinetics of talc are studied as a function of temperature, grain size, composition and fluid fugacity, as part of a systematic study of the reaction kinetics of the volatile bearing phases that are either known or likely to be present in carbonaceous chondrites. The dehydration kinetics were investigated at 1 bar, 775 to 875 C by monitoring the in-situ weight loss as a function of time of a natural talc. The talc platelets had a dimension of 0.8 to 1 micron. The run durations varied from 233.3 hours at 775 C (48 percent dehydration) to 20.8 hours at 875 C (80 pct. dehydration). The results can be adequately represented by a given rate equation. Theoretical analysis suggests that the reduction in the concentration of H2O in the environment of dehydrating talc, as would be encountered in processing chondritic materials, will have negligible effect on the rate of dehydration, unless there is a change of reaction mechanism owing to the presence of other volatile species.

  3. Biosynthesis and Emission of Terpenoid Volatiles from Arabidopsis Flowers

    PubMed Central

    Chen, Feng; Tholl, Dorothea; D'Auria, John C.; Farooq, Afgan; Pichersky, Eran; Gershenzon, Jonathan

    2003-01-01

    Arabidopsis is believed to be mostly self-pollinated, although several lines of genetic and morphological evidence indicate that insect-mediated outcrossing occurs with at least a low frequency in wild populations. Here, we show that Arabidopsis flowers emit both monoterpenes and sesquiterpenes, potential olfactory cues for pollinating insects. Of the 32 terpene synthase genes in the Arabidopsis genome, 20 were found to be expressed in flowers, 6 of these exclusively or almost exclusively so. Two terpene synthase genes expressed exclusively in the flowers and one terpene synthase gene expressed almost exclusively in the flowers were characterized and found to encode proteins that catalyze the formation of major floral volatiles. A ?-glucuronidase fusion construct with a promoter of one of these genes demonstrated that gene expression was restricted to the sepals, stigmas, anther filaments, and receptacles, reaching a peak when the stigma was receptive to cross pollen. The observation that Arabidopsis flowers synthesize and emit volatiles raises intriguing questions about the reproductive behavior of Arabidopsis in the wild and allows detailed investigations of floral volatile biosynthesis and its regulation to be performed with this model plant system. PMID:12566586

  4. Mercury Polar Volatiles: Complex Hydrocarbons vs Water Ice

    NASA Astrophysics Data System (ADS)

    Neumann, G. A.; Mazarico, E.; Zuber, M. T.; Smith, D. E.; Paige, D. A.; Solomon, S. C.; Ernst, C. M.; Barnouin, O. S.; Mao, D.

    2012-12-01

    Radiometric measurements by MLA elucidate the emplacement and sequestration of volatiles on Mercury, repeatedly imaged by Earth-based radar. We have reported [Neumann et al., 2012, LPSC, #2651] the presence of MLA-dark deposits coinciding with many of the radar-bright regions thought to indicate the presence of subsurface ice. Thermal models [Paige et al., 2012, LPSC, #2875] suggest that at certain latitudes, maximum temperatures exceed the regime of stability of surface water ice, but average subsurface temperatures allow its persistence there against sublimation. At the highest latitudes, where radar signatures fill large portions of polar craters, measurements by MLA are at the noise limit for measuring reflectance; however, several profiles have been obtained with useful energy data. We explore the working hypothesis that dark, complex organics (common in asteroids & comets) overly water ice, providing an important constraint on thermal models of polar regions. Repeated profiles are being acquired in the extended mission in order to more clearly delineate the boundaries of volatile deposits. A good sampling of craters over the appropriate latitude range will further constrain the composition of volatiles. We will report on further mapping in the MESSENGER Extended Mission to the coldest north polar regions, where the majority of ices lie.

  5. Volatile constituents of two rare subspecies of Thymus praecox.

    PubMed

    Vidic, Danijela; Cavar, Sanja; Soli?, Marija Edita; Maksimovi?, Milka

    2010-07-01

    Hydrodistilled essential oil and the corresponding headspace volatiles of Bosnian wild growing Thymus praecox ssp. polytrichus (A. Kern. Ex Borbàs) Jalas and Thymus praecox ssp. skorpilii (Velen.) Jalas were subjected to capillary GC-MS analysis. This work presents a detailed essential oil analysis of these two rare Thymus subspecies from Bosnia, as well as the very first report on their headspace composition. Eighty-seven volatile constituents were identified in four samples. Two alcohols were the major constituents in the essential oil of T. praecox ssp. polytrichus, a monoterpene, linalool (13.9%), and a sesquiterpene, (E)-nerolidol (10.4%), while linalyl acetate (36.7%) and linalool (22.7%) were the most abundant volatiles in the corresponding headspace sample. Oxygenated monoterpenes (57.5%) predominate in the essential oil of T. praecox ssp. skorpilii with linalyl acetate (28.7%) and linalool (14.4%) as the main representatives. Headspace sample of this subspecies also showed richness in linalyl acetate (52.4%), while the second most abundant compound was alpha-pinene (14.5%), a monoterpene hydrocarbon. PMID:20734955

  6. Selenium detoxification by volatilization and precipitation in aquatic plants

    SciTech Connect

    Fan, T.W.M.; Higashi, R.M. [Univ. of California, Davis, CA (United States)

    1995-12-31

    The narrow margin of requirement and toxicity for selenium makes it a difficult pollution problem to solve. Selenium bioaccumulation has been a major threat to wildlife in California and is becoming a major concern in the San Francisco Bay/Estuaries. Despite the past efforts in Se nutrition, chemistry, and remediation, its toxicity and detoxification mechanism(s) in wildlife, particularly primary producers, is still unclear, due to a lack of understanding in Se biochemistry. This is becoming a critical issue in assessing Se risk and remediation. To address this gap, the authors have been characterizing Se speciation and its linkage to detoxification mechanism(s) of two indigenous aquatic plants, duckweed (Lemna minor) and a microphyte (Chlorella). Using GT-MS analysis, they found that Chlorella monocultures transformed Se oxyanions into volatile dimethylselenide and dimethyidiselenide and into insoluble So at extremely high Se (up to 750 ppm) concentrations. This alga did not accumulate selenomethionine which is among the most toxic forms of Se to wildlife. Dimethylsulfide was also volatilized, consistent with the hypothesis that dimethylsulfide/dimethylselenide emissions share a similar biochemical pathway. Se-treated Chlorella biomass released dimethylsulfide/dimethylselenide upon alkaline hydrolysis, suggesting the presence of dimethylsulfonium and dimethylselenonium propionates. Dimethylsulfoniumpropionate is known as an osmoprotectant in marine phytoplankton and as a major contributor to global biogenic dimethylsulfide emissions. Dimethylselenoniumpropionate has not been identified previously and may be a byproduct of dimethylsulfoniumpropionate synthesis. The unusual Se tolerance of Chlorella may be due to its ability to volatilize and precipitate Se. Such activities may be utilized for in situ Se bioremediation. Similar investigations with duckweed is underway.

  7. Variability of volatile constituents in Artemisia maritima in western Himalaya.

    PubMed

    Jaitak, Vikas; Singh, Bikram; Kaul, V K

    2008-05-10

    Chemical composition of the essential oil of Artemisia maritima, collected from three different high altitude locations in western Himalaya was studied by gas-chromatography mass spectrometry. Twenty-five constituents were identified in the oil distilled from the sample from Pooh, of which 1,8-cineole (23.8%) and chrysanthenone (17.54%) were the major constituents. Twenty volatile constituents were identified from the sample collected from Rhongtong pass, of which chrysanthenone (38.1%) and 1,8-cineole (37.3%) were the major constituents. In the oil distilled from the sample collected from Lahaul-Spiti 28 constituents were identified, of which 1,8-cineole (44.22%), camphor (9.16%) and borneol (10.94%) were the major constituents. In this sample chrysanthenone was present in very low percentage. PMID:18569692

  8. Identification of Major Histocompatibility Complex-Regulated Body Odorants by Statistical Analysis of a Comparative Gas Chromatography/Mass Spectrometry Experiment

    SciTech Connect

    Willse, Alan R.; Belcher, Ann; Preti, George; Wahl, Jon H.; Thresher, Miranda; Yang, Peter; Yamazaki, Kunio; Beauchamp, Gary

    2005-04-15

    Gas chromatography (GC), combined with mass spectrometry (MS) detection, is a powerful analytical technique that can be used to separate, quantify, and identify volatile compounds in complex mixtures. This paper examines the application of GC-MS in a comparative experiment to identify volatiles that differ in concentration between two groups. A complex mixture might comprise several hundred or even thousands of volatile compounds. Because their number and location in a chromatogram generally are unknown, and because components overlap in populous chromatograms, the statistical problems offer significant challenges beyond traditional two-group screening procedures. We describe a statistical procedure to compare two-dimensional GC-MS profiles between groups, which entails (1) signal processing: baseline correction and peak detection in single ion chromatograms; (2) aligning chromatograms in time; (3) normalizing differences in overall signal intensities; and (4) detecting chromatographic regions that differ between groups. Compared to existing approaches, the proposed method is robust to errors made at earlier stages of analysis, such as missed peaks or slightly misaligned chromatograms. To illustrate the method, we identify differences in GC-MS chromatograms of ether-extracted urine collected from two nearly identical inbred groups of mice, to investigate the relationship between odor and genetics of the major histocompatibility complex.

  9. Breath measurements as volatile organic compound biomarkers

    SciTech Connect

    Wallace, L.; Buckley, T. [Environmental Protection Agency, Reston, VA (United States); Pellizzari, E. [Research Triangle Institute, Research Triangle Park, NC (United States); Gordon, S. [Battelle Memorial Institute, Columbus, OH (United States)

    1996-10-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency`s large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times, {tau}{sub i} in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. 81 refs., 3 figs., 4 tabs.

  10. Volatile Anesthetics and AKI: Risks, Mechanisms, and a Potential Therapeutic Window

    PubMed Central

    Fukazawa, Kyota

    2014-01-01

    AKI is a major clinical problem with extremely high mortality and morbidity. Kidney hypoxia or ischemia-reperfusion injury inevitably occurs during surgery involving renal or aortic vascular occlusion and is one of the leading causes of perioperative AKI. Despite the growing incidence and tremendous clinical and financial burden of AKI, there is currently no effective therapy for this condition. The pathophysiology of AKI is orchestrated by renal tubular and endothelial cell necrosis and apoptosis, leukocyte infiltration, and the production and release of proinflammatory cytokines and reactive oxygen species. Effective management strategies require multimodal inhibition of these injury processes. Despite the past theoretical concerns about the nephrotoxic effects of several clinically utilized volatile anesthetics, recent studies suggest that modern halogenated volatile anesthetics induce potent anti-inflammatory, antinecrotic, and antiapoptotic effects that protect against ischemic AKI. Therefore, the renal protective properties of volatile anesthetics may provide clinically useful therapeutic intervention to treat and/or prevent perioperative AKI. In this review, we outline the history of volatile anesthetics and their effect on kidney function, briefly review the studies on volatile anesthetic-induced renal protection, and summarize the basic cellular mechanisms of volatile anesthetic-mediated protection against ischemic AKI. PMID:24511126

  11. Sulfur volatiles in guava (Psidium guajava L.) leaves: possible defense mechanism.

    PubMed

    Rouseff, Russell L; Onagbola, Ebenezer O; Smoot, John M; Stelinski, Lukasz L

    2008-10-01

    Volatiles from crushed and intact guava leaves (Psidium guajava L.) were collected using static headspace SPME and determined using GC-PFPD, pulsed flame photometric detection, and GC-MS. Leaf volatiles from four common citrus culitvars were examined similarly to determine the potential component(s) responsible for guava's protective effect against the Asian citrus psyllid (Diaphorina citri Kuwayama), which is the insect vector of Huanglongbing (HLB) or citrus greening disease. Seven sulfur volatiles were detected: hydrogen sulfide, sulfur dioxide, methanethiol, dimethyl sulfide (DMS), dimethyl disulfide (DMDS), methional, and dimethyl trisulfide (DMTS). Identifications were based on matching linear retention index values on ZB-5, DB-Wax, and PLOT columns and MS spectra in the case of DMDS and DMS. DMDS is an insect toxic, defensive volatile produced only by wounded guava but not citrus leaves and, thus, may be the component responsible for the protective effect of guava against the HLB vector. DMDS is formed immediately after crushing, becoming the major headspace volatile within 10 min. Forty-seven additional leaf volatiles were identified from LRI and MS data in the crushed guava leaf headspace. PMID:18778077

  12. Volatile-Mediated Killing of Arabidopsis thaliana by Bacteria Is Mainly Due to Hydrogen Cyanide? †

    PubMed Central

    Blom, Dirk; Fabbri, Carlotta; Eberl, Leo; Weisskopf, Laure

    2011-01-01

    The volatile-mediated impact of bacteria on plant growth is well documented, and contrasting effects have been reported ranging from 6-fold plant promotion to plant killing. However, very little is known about the identity of the compounds responsible for these effects or the mechanisms involved in plant growth alteration. We hypothesized that hydrogen cyanide (HCN) is a major factor accounting for the observed volatile-mediated toxicity of some strains. Using a collection of environmental and clinical strains differing in cyanogenesis, as well as a defined HCN-negative mutant, we demonstrate that bacterial HCN accounts to a significant extent for the deleterious effects observed when growing Arabidopsis thaliana in the presence of certain bacterial volatiles. The environmental strain Pseudomonas aeruginosa PUPa3 was less cyanogenic and less plant growth inhibiting than the clinical strain P. aeruginosa PAO1. Quorum-sensing deficient mutants of C. violaceum CV0, P. aeruginosa PAO1, and P. aeruginosa PUPa3 showed not only diminished HCN production but also strongly reduced volatile-mediated phytotoxicity. The double treatment of providing plants with reactive oxygen species scavenging compounds and overexpressing the alternative oxidase AOX1a led to a significant reduction of volatile-mediated toxicity. This indicates that oxidative stress is a key process in the physiological changes leading to plant death upon exposure to toxic bacterial volatiles. PMID:21115704

  13. Advanced steady-state model for the fate of hydrophobic and volatile compounds in activated sludge

    SciTech Connect

    Lee, K.C.; Rittmann, B.E.; Shi, J.; McAvoy, D.

    1998-09-01

    A steady-state, advanced, general fate model developed to study the fate of organic compounds in primary and activated-sludge systems. This model considers adsorption, biodegradation from the dissolved and adsorbed phases, bubble volatilization, and surface volatilization as removal mechanisms. A series of modeling experiments was performed to identify the key trends of these removal mechanisms for compounds with a range of molecular properties. With typical municipal wastewater treatment conditions, the results from the modeling experiments show that co-metabolic and primary utilization mechanisms give very different trends in biodegradation for the compounds tested. For co-metabolism, the effluent concentration increases when the influent concentration increases, while the effluent concentration remains unchanged when primary utilization occurs. For a highly hydrophobic compound, the fraction of compound removed from adsorption onto primary sludge can be very important, and the direct biodegradation of compound sorbed to the activated sludge greatly increases its biodegradation and reduces its discharge with the waste activated sludge. Volatilization from the surface of the primary and secondary systems is important for compounds with moderate to high volatilities, especially when these compounds are not biodegradable. Finally, bubble volatilization can be a major removal mechanism for highly volatile compounds even when they are highly biodegradable.

  14. Volatile hydrocarbons in pharmaceutical solutions

    SciTech Connect

    Kroneld, R. (Department of Medicine, University of Turku (Finland))

    1991-07-01

    Volatile pollutants such as hydrocarbons have, during many years, been analysed in small concentrations in air, water, food, pharmaceutical solutions, and human blood and tissues. It has also been shown that such substances have unexpected consequences for cell cultures and scientific experiments. These substances also accumulate in patients receiving haemodialysis and these patients are exposed to quite high concentrations. The knowledge of the toxicity of such compounds has led to the development of maximum limit concentrations with the aim to decrease the exposure of humans. This paper discusses the problems of human exposure in general and especially through pharmaceutical solutions, and the possibilities of eliminating such compounds with the aim of decreasing the exposure as a hygienic challenge.

  15. Chemical composition of Silene morganae Freyn volatile oil.

    PubMed

    Azadi, Boshra; Sohrabi, Yousef

    2015-01-01

    The essential oil composition of flowering aerial parts of Iranian Silene morganae Freyn (Caryophyllaceae) was analysed for the first time using gas chromatography and gas chromatography-mass spectrometry. Thirty-one compounds consisting of 90.3% of the volatile oil were detected. The major constituents were benzaldehyde (11.6%), (Z)-3-hexenyl acetate (9.6%), (E)-?-ocimene (8.2%) and linalool (7.4%). Terpenoids (43.5%), particularly monoterpene hydrocarbons (24.2%), had the highest contribution in S. morganae Freyn flowering aerial parts oil. PMID:25422069

  16. Volatile flavor constituents of acerola (Malpighia emarginata DC.) fruit.

    PubMed

    Pino, J A; Marbot, R

    2001-12-01

    Volatile components were isolated from acerola fruit by simultaneous steam distillation-solvent extraction according to the Likens-Nickerson method and analyzed by GC and GC-MS methods. One hundred fifty constituents were identified in the aroma concentrate, from which furfural, hexadecanoic acid, 3-methyl-3-butenol, and limonene were found to be the major constituents. The amounts of esters, 3-methyl-3-butenol, and their various esters were thought to contribute to the unique flavor of the acerola fruit. PMID:11743778

  17. Measurement of non-volatile particle number size distribution

    NASA Astrophysics Data System (ADS)

    Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

    2015-06-01

    An experimental methodology was developed to measure the non-volatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a non-volatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol, OA (40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a non-volatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon (BC) with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

  18. Volatile components associated with bacterial spoilage of tropical prawns.

    PubMed

    Chinivasagam, H N; Bremner, H A; Wood, A F; Nottingham, S M

    1998-06-30

    Analysis of headspace volatiles by gas chromatography/mass spectrometry from king (Penaeus plebejus), banana (P. merguiensis), tiger (P. esculentus/semisulcatus) and greasy (Metapenaeus bennettae) prawns stored in ice or ice slurry, which is effectively an environment of low oxygen tension, indicated the presence of amines at the early stages of storage (less than 8 days) irrespective of the nature of the storage media. Esters were more prevalent in prawns stored on ice (normal oxygen conditions) at the latter stages of storage (more than 8 days) and were only produced by Pseudomonas fragi, whereas sulphides and amines occurred whether the predominant spoilage organism was Ps. fragi or Shewanella putrefaciens. The free amino acid profiles of banana and king prawns were high in arginine (12-14%) and low in cysteine (0.1-0.17%) and methionine (0.1-0.2%). Filter sterilised raw banana prawn broth inoculated with a total of 15 cultures of Ps. fragi and S. putrefaciens and incubated for two weeks at 5 degrees C, showed the presence of 17 major compounds in the headspace volatiles analysed using gas chromatography/mass spectrometry (GC/MS). These were mainly amines, sulphides, ketones and esters. Principal Component Analysis of the results for the comparative levels of the volatiles produced by pure cultures, inoculated into sterile prawn broth, indicated three subgroupings of the organisms; I, Ps. fragi from a particular geographic location; II, S. putrefaciens from another geographic location; and III, a mixture of Ps. fragi and S. putrefaciens from different geographic locations. The sensory impression created by the cultures was strongly related to the chemical profile as determined by GC/MS. Organisms, even within the same subgrouping classified as identical by the usual tests, produced a different range of volatiles in the same uniform substrate. PMID:9706797

  19. Outgassing and degradation of polyimide induced by swift heavy ion irradiation at cryogenic temperature

    SciTech Connect

    Severin, D. [Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); GSI-Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Balanzat, E. [CIMAP-CIRIL, CEA-CNRS-ENSICAEN, 14050 Caen cedex 4 (France); Ensinger, W. [Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); Trautmann, C. [GSI-Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany)

    2010-07-15

    Polyimide foils were irradiated with energetic Kr (740 MeV) and Pb (890 MeV) ions at cryogenic temperature (12 K). Beam-induced degradation processes were monitored by residual gas analysis and online infrared spectroscopy. The outgassing components observed at low irradiation temperatures differ in quantity but are similar in mass distribution to those identified at room temperature exposure. Besides CO as major volatile fragment, a significant contribution of short hydrocarbons like C{sub 2}H{sub x} is released. In situ infrared spectroscopy indicates accumulation of CO and CO{sub 2} molecules at 12 K in the foils. During heat-up cycles, most of these frozen gases become mobile and outgas at a temperature between 35 and 55 K. The study is motivated by the application of polyimide foils as insulating material in high radiation environment of the future accelerator facility for antiproton and ion research (FAIR).

  20. Volatile anesthetic-induced preconditioning.

    PubMed

    Swyers, T; Redford, D; Larson, D F

    2014-01-01

    The myocardium has an innate ability to protect itself from ischemic events. This protection occurs when the myocardium is exposed to a brief ischemic period prior to a more extreme ischemic event. This is termed ischemic preconditioning. Ischemic preconditioning induces a series of molecular pathways that protect the cardiac myocyte; first, for a period of 1-6 hours (early preconditioning) and, also, for a second period from 24-72 hours (delayed phase). The early preconditioning is mediated by the release of adenosine which induces a protective signal that is related to the mitochondrial KATP channel activation and activation of the ?-opioid and bradykinin receptors. The delayed phase is related to the induction of inducible nitric oxide synthase, superoxide dismutase and heat-shock proteins. Indirect evidence indicates that O2-derived free radicals are involved in the delayed phase, as noted in the early preconditioning phase. Applying ischemic preconditioning to clinical practice can be dangerous and difficult to implement in a controlled fashion. However, recent studies have shown that the use of volatile anesthetics, such as sevoflurane, isoflurane and desflurane, can mimic the early phase of ischemic preconditioning through a multi-pathway signaling of mitochondrial KATP channels. This important finding can easily be applied to clinical practice for patients undergoing surgery. It can also be significantly important for patients undergoing off-pump cardiac bypass surgery or cardiac bypass surgery where there is no cross-clamp or cardioplegia used where the probability of myocardial ischemia is greatly increased. This report will, therefore, discuss the mechanism, safety and efficacy of volatile anesthetics as inducers of cardiac preconditioning. PMID:24002781

  1. Volatile emissions from an epiphytic fungus are semiochemicals for eusocial wasps.

    PubMed

    Davis, Thomas Seth; Boundy-Mills, Kyria; Landolt, Peter J

    2012-11-01

    Microbes are ubiquitous on plant surfaces. However, interactions between epiphytic microbes and arthropods are rarely considered as a factor that affects arthropod behaviors. Here, volatile emissions from an epiphytic fungus were investigated as semiochemical attractants for two eusocial wasps. The fungus Aureobasidium pullulans was isolated from apples, and the volatile compounds emitted by fungal colonies were quantified. The attractiveness of fungal colonies and fungal volatiles to social wasps (Vespula spp.) were experimentally tested in the field. Three important findings emerged: (1) traps baited with A. pullulans caught 2750 % more wasps on average than unbaited control traps; (2) the major headspace volatiles emitted by A. pullulans were 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-phenylethyl alcohol; and (3) a synthetic blend of fungal volatiles attracted 4,933 % more wasps on average than unbaited controls. Wasps were most attracted to 2-methyl-1-butanol. The primary wasp species attracted to fungal volatiles were the western yellowjacket (Vespula pensylvanica) and the German yellowjacket (V. germanica), and both species externally vectored A. pullulans. This is the first study to link microbial volatile emissions with eusocial wasp behaviors, and these experiments indicate that volatile compounds emitted by an epiphytic fungus can be responsible for wasp attraction. This work implicates epiphytic microbes as important components in the community ecology of some eusocial hymenopterans, and fungal emissions may signal suitable nutrient sources to foraging wasps. Our experiments are suggestive of a potential symbiosis, but additional studies are needed to determine if eusocial wasp-fungal associations are widespread, and whether these associations are incidental, facultative, or obligate. PMID:22644482

  2. Estimation of ammonia volatilization from surface-applied urea as indicated by bermudagrass N-use efficiency 

    E-print Network

    Drwal, John Matthew

    1986-01-01

    ESTIMATION OF AMMONIA VOLATILIZATION FROM SURFACE-APPLIED UREA AS INDICATED BY BERMUDAGRASS N-USE EFFICIENCY A Thesis by JOHN MATTHEW DRWAL Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1986 Major Subject: Soil Science ESTIMATION OF AMMONIA VOLATILIZATION FROM SURFACE-APPLIED UREA AS INDICATED BY BERMUDAGRASS N-USE EFFICIENCY A Thesis by JOHN MATTHEW DRWAL Approved as to style and content by...

  3. Electrophysiological responses of Thaumetopoea pityocampa females to host volatiles: implications for host selection of active and inactive terpenes

    Microsoft Academic Search

    Q.-H. Zhang; F. Schlyter; A. Battisti; G. Birgersson; P. Anderson

    2003-01-01

    Volatiles from newly cut branches with needles of Pinus sylvestris L. were collected with headspace sampling technique, and then identified and quantified by combined gas chromatographic-mass spectrometry (GC-MS). The response of antennae of the female pine processionary moth, Thaumetopoea pityocampa, to these volatiles was recorded by coupled gas chromatographic-electroantennographic detection (GC-EAD). Surprisingly, the most common and major monoterpene hydrocarbons (MT),

  4. Comparison of fermented soybean paste (Doenjang) prepared by different methods based on profiling of volatile compounds.

    PubMed

    Jo, Ye-Jin; Cho, In Hee; Song, Chi Kwang; Shin, Hye Won; Kim, Young-Suk

    2011-04-01

    In this study, 2 different extraction methods, namely solvent-assisted flavor evaporation (SAFE) and solid-phase microextraction (SPME), were employed to investigate the comprehensive volatile profile of?Doenjang?(one of Korean fermented soybean pastes) efficiently. Quantitatively, major volatiles of?Doenjang?isolated by SAFE were 3-methylbutanoic acid, butanoic acid, 3-hydroxy-2-methyl-4H-pyran-4-one (maltol), ethyl 2-methylbutanoate, 2-methylpropanoic acid, tetramethylpyrazine, and 4-ethyl-2-methoxyphenol, while ethanol, ethenylbenzene, ethyl benzoate, ethyl linoleate, ethyl acetate, ethyl butanoate, tetramethylpyrazine, and ethyl 2-methylpropanoate extracted by SPME. In addition, volatile profiling that applied principal component analysis to gas chromatography-mass spectrometry datasets allowed?Doenjang?samples that had been prepared using different traditional and commercial methods to be discriminated, and the volatile compounds that contributed to their discrimination were assigned. The major volatiles that were related to differentiation of traditional and commercial?Doenjang?samples were 2-pentylfuran, 4-ethylphenol, dihydro-5-methyl-2(3H)-furanone, butanoic acid, pyrazines (for example, 2-ethyl-5-methylpyrazine and 2,3-dimethylpyrazine), esters (for example, ethyl 4-methylpentanoate and diethyl succinate), maltol, dimethyl disulfide, 2- and 3-methylbutanal, hexanal, 4-vinylphenol, and ethanol. PMID:21535802

  5. Attraction of the gypsy moth to volatile organic compounds (VOCs) of damaged Dahurian larch.

    PubMed

    Li, Jing; Valimaki, Sanna; Shi, Juan; Zong, Shixiang; Luo, Youqing; Heliovaara, Kari

    2012-01-01

    Olfactory responses of the gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae), a major defoliator of deciduous trees, were examined in Inner Mongolia, China. We studied whether the gypsy moth adults are attracted by the major volatile organic compounds (VOCs) of damaged Larix gmelinii (Dahurian larch) foliage and compared the attractiveness of the plant volatiles with that of the synthetic sex pheromone. Our results indicated that the VOCs of the Dahurian larch were effective in attracting gypsy moth males especially during the peak flight period. The VOCs also attracted moths significantly better than the sex pheromone of the moth. Our study is the first trial to show the responses of adult gypsy moths to volatile compounds emitted from a host plant. Electroantennogram responses of L. gmelinii volatiles on gypsy moths supported our field observations. A synergistic effect between host plant volatiles and sex pheromone was also obvious, and both can be jointly applied as a new attractant method or population management strategy of the gypsy moth. PMID:23016284

  6. Impact of oil price volatility on Gulf Cooperation Council stock markets' return

    Microsoft Academic Search

    Ibrahim A. Onour

    2007-01-01

    AbstractThis paper investigates the short and long-term determinants of Gulf Cooperation Council (GCC) stock markets' volatility. Since GCC countries are major suppliers of oil in world energy markets, their stock markets are likely to be susceptible to change in oil prices. Given that change in oil prices influence observable factors in GCC economies, we show in this paper that unobservable

  7. Reactions of volatile organic compounds in the atmosphere: Ozone-alkene reactions

    Microsoft Academic Search

    Jill Denise Fenske

    2000-01-01

    Photochemical smog cannot form without sunlight, nitrogen oxides, and volatile organic compounds (VOC). This dissertation addresses several different aspects of VOC chemistry in the atmosphere. Aside from ambient levels of VOC outdoors, VOC are also present at moderate concentrations indoors. Many studies have measured indoor air concentrations of VOC, but only one considered the effects of human breath. The major

  8. Volatile organic compounds in snow in the Quebec-Windsor Corridor

    Microsoft Academic Search

    G. Kos; P. A. Ariya

    2010-01-01

    Volatile organic compounds (VOC) were determined in snow to investigate the role of the snowpack as an exchange medium for atmospherically active compounds of anthropogenic and biogenic origin. The major question was which VOC species occur in snow and how the species identity and selected concentrations are related to the sampling area and environmental conditions. Samples were collected using a

  9. VOLATILE ORGANIC COMPOUNDS AND ISOPRENE OXIDATION PRODUCTS AT A TEMPERATE DECIDUOUS FOREST SITE

    EPA Science Inventory

    Biogenic volatile compounds (BVOCs) and their role in atmospheric oxidant formation were investigated at a forest site near Oak Ridge, Tennessee, as part of the Nashville Southern Oxidants Study (SOS) in July 1995. Of 98 VOCs detected, a major fraction were anthropogenic VOCs suc...

  10. The Indoor Volatile Organic Compounds (VOCs) Pollution Control Methods - A Case Study

    Microsoft Academic Search

    Lei Yuan; NanYang Yu

    2010-01-01

    An aim in study volatile organic compound (VOCs) emission is to improve indoor air quality. VOCs are the major indoor air pollutants, this paper introduced the types ,sources and characteristics of pollution caused by VOCs in indoor air, and effect of VOCs on human health were presented. The pollution from sources, adsorption technology and photocatalytic oxidation technology ect. In order

  11. Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their waste as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOC) and greenhouse gases (GH...

  12. Volatile Production by Buds and Corollas of Two Sympatric, Confamilial Plants, Ipomopsis aggregata and Polemonium foliosissimum

    Microsoft Academic Search

    Rebecca E. Irwin; Bob Dorsett

    2002-01-01

    We used solid-phase microextraction of headspace samples followed by gas chromatography and mass spectrometry to identify and quantify the major volatile compounds produced by the buds and corollas of Ipomopsis aggregata (Polemoniaceae), and we compared them to a sympatric, confamilial plant species, Polemonium foliosissimum. The two species have distinct floral morphologies and pollinators, but share a common predispersal seed predator

  13. Flower Volatiles, Crop Varieties and Bee Responses

    PubMed Central

    Klatt, Björn K.; Burmeister, Carina; Westphal, Catrin; Tscharntke, Teja; von Fragstein, Maximillian

    2013-01-01

    Pollination contributes to an estimated one third of global food production, through both the improvement of the yield and the quality of crops. Volatile compounds emitted by crop flowers mediate plant-pollinator interactions, but differences between crop varieties are still little explored. We investigated whether the visitation of crop flowers is determined by variety-specific flower volatiles using strawberry varieties (Fragaria x ananassa Duchesne) and how this affects the pollination services of the wild bee Osmia bicornis L. Flower volatile compounds of three strawberry varieties were measured via headspace collection. Gas chromatography showed that the three strawberry varieties produced the same volatile compounds but with quantitative differences of the total amount of volatiles and between distinct compounds. Electroantennographic recordings showed that inexperienced females of Osmia bicornis had higher antennal responses to all volatile compounds than to controls of air and paraffin oil, however responses differed between compounds. The variety Sonata was found to emit a total higher level of volatiles and also higher levels of most of the compounds that evoked antennal responses compared with the other varieties Honeoye and Darselect. Sonata also received more flower visits from Osmia bicornis females under field conditions, compared with Honeoye. Our results suggest that differences in the emission of flower volatile compounds among strawberry varieties mediate their attractiveness to females of Osmia bicornis. Since quality and quantity of marketable fruits depend on optimal pollination, a better understanding of the role of flower volatiles in crop production is required and should be considered more closely in crop-variety breeding. PMID:23977347

  14. Semi-volatile secondary organic aerosol in urban atmospheres: meeting a measurement challenge

    NASA Astrophysics Data System (ADS)

    Eatough, Delbert J.; Long, Russell W.; Modey, William K.; Eatough, Norman L.

    Ammonium nitrate and semi-volatile organic compounds are significant components of fine particles in urban atmospheres. These components, however, are not properly determined with current US EPA accepted methods such as the PM 2.5 FRM or other single filter samplers due to significant losses of semi-volatile material (SVM) from particles collected on the filter during sampling. Continuous PM 2.5 mass measurements are attempted using methods such as the R&P TEOM monitor. This method, however, heats the sample to remove particle-bound water which also results in evaporation of SVM. Research at Brigham Young University has resulted in samplers for both the integrated and continuous measurement of total PM 2.5, including the SVM. The PC-BOSS is a charcoal diffusion denuder based sampler for the determination of fine particulate chemical composition including the semi-volatile organic material. The RAMS is a modified TEOM monitor which includes diffusion denuders and Nafion dryers to remove gas phase material which can be absorbed by a charcoal sorbent filter. The RAMS then uses a "sandwich filter" consisting of a conventional particle collecting Teflon coated TX40 filter, followed by an activated charcoal sorbent filter which retains any semi-volatile ammonium nitrate or organic material lost from the particles collected on the TEOM monitor Teflon coated filter, thus allowing for determination of total PM 2.5 mass including the SVM. Recent research conducted by Brigham Young University using these two samplers has indicated the following about semi-volatile organic aerosol: The majority of semi-volatile fine particulate organic material is secondary organic aerosol. This semi-volatile organic aerosol is not retained on the heated filter of a regular TEOM monitor and hence is not measured by this sampling technique. In addition, secondary ammonium nitrate is also lost. Much of the semi-volatile organic aerosol is also lost during sampling from single filter samplers such as the PM 2.5 FRM sampler. The amount of semi-volatile organic aerosol lost from single filter samplers can vary from less than 1/3 that lost from heated TEOM filters during cold winter conditions to essentially all during warm summer conditions. Semi-volatile organic aerosol can only be reliably collected using an appropriate denuder sampler. Either a PM 2.5 FRM sampler or the IMPROVE sampler can be easily modified to a denuder sampler with filters which can be analyzed for semi-volatile OC, nonvolatile OC and EC using existing OC/EC analytical techniques. The research upon which these statements are based is summarized in this document.

  15. Magmatic volatiles in explosive rhyolitic eruptions

    SciTech Connect

    Eichelberger, J.C.; Westrich, H.R.

    1981-07-01

    Obsidian clasts in rhyolitic tephra deposits preserve preeruption magmatic volatile contents, providing a direct means for determining the volatile content of explosively erupted magmas. Small to moderate volume Plinian eruptions (10/sup -3/ to 10/sup -1/ km/sup 3/) appear to be driven by 0.5--1.0 wt.% volatiles, consisting dominantly of H/sub 2/O with minor CO/sub 2/. Analysis of obsidian from eruptive sequences consisting of tephra and flows indicates that this hydrous magma abruptly overlies magma with only 0.1--0.2 wt.% H/sub 2/O.

  16. Malaria Parasites Produce Volatile Mosquito Attractants

    PubMed Central

    Kelly, Megan; Su, Chih-Ying; Schaber, Chad; Crowley, Jan R.; Hsu, Fong-Fu; Carlson, John R.

    2015-01-01

    ABSTRACT The malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid organelle that possesses plant-like metabolic pathways. Plants use the plastidial isoprenoid biosynthesis pathway to produce volatile odorants, known as terpenes. In this work, we describe the volatile chemical profile of cultured malaria parasites. Among the identified compounds are several plant-like terpenes and terpene derivatives, including known mosquito attractants. We establish the molecular identity of the odorant receptors of the malaria mosquito vector Anopheles gambiae, which responds to these compounds. The malaria parasite produces volatile signals that are recognized by mosquitoes and may thereby mediate host attraction and facilitate transmission. PMID:25805727

  17. Concentrations of Volatiles in the Lunar Regolith

    NASA Technical Reports Server (NTRS)

    Taylor, Jeff; Taylor, Larry; Duke, Mike

    2007-01-01

    To set lower and upper limits on the overall amounts and types of volatiles released during heating of polar regolith, we examined the data for equatorial lunar regolith and for the compositions of comets. The purpose, specifically, was to answer these questions: 1. Upper/Lower limits and 'best guess' for total amount of volatiles (by weight %) released from lunar regolith up to 150C 2. Upper/Lower limit and 'best guess' for composition of the volatiles released from the lunar regolith by weight %

  18. Two terpene synthases are responsible for the major sesquiterpenes emitted from the flowers of kiwifruit (Actinidia deliciosa)

    Microsoft Academic Search

    Niels J. Nieuwenhuizen; Mindy Y. Wang; Adam J. Matich; Sol A. Green; Xiuyin Chen; Yar-Khing Yauk; Lesley L. Beuning; Dinesh A. Nagegowda; Natalia Dudareva; Ross G. Atkinson

    2009-01-01

    Kiwifruit vines rely on bees for pollen transfer between spatially separated male and female individuals and require synchronized flowering to ensure pollination. Volatile terpene compounds, which are important cues for insect pollinator attraction, were studied by dynamic headspace sampling in the major green-fleshed kiwifruit (Actinidia deliciosa) cultivar 'Hayward' and its male pollinator 'Chieftain'. Terpene volatile levels showed a profile dominated

  19. Effect of ?-irradiation on the volatile oil constituents of fresh ginger (zingiber officinale) rhizome

    Microsoft Academic Search

    Prasad S. Variyar; A. S. Gholap; P. Thomas

    1997-01-01

    Volatile essential oils of fresh ginger rhizomes gamma irradiated (60 Gy) for sprout inhibition and non-irradiated control rhizomes were isolated by simultaneous distillation-extraction technique. Major compounds present in these oils were identified by GLC and GC\\/MS analysis. Zingiberin, ?-sesquiphellandrene and ar-curcumene were the major compounds identified with zingiberin accounting for 40% of the essential oil. ?-irradiation at a dose of

  20. Housewives’ exposure to volatile organic compounds relative to proximity to roadside service stations

    Microsoft Academic Search

    Wan-Kuen Jo; Kung-Cho Moon

    1999-01-01

    Residents in neighborhoods near a service station and\\/or major roadway would be expected to be exposed to elevated ambient volatile organic compound (VOC) levels compared to those further away from such source(s). We confirmed this and examined whether the anticipated high outdoor levels near a service station and\\/or major roadway outweighed the indoor levels as a factor for the exposure

  1. Electricity market price volatility: The case of Ontario

    Microsoft Academic Search

    Hamidreza Zareipour; Kankar Bhattacharya; Claudio A. Cañizares

    2007-01-01

    Price volatility analysis has been reported in the literature for most competitive electricity markets around the world. However, no studies have been published yet that quantify price volatility in the Ontario electricity market, which is the focus of the present paper. In this paper, a comparative volatility analysis is conducted for the Ontario market and its neighboring electricity markets. Volatility

  2. Electricity market price volatility: The case of Ontario

    Microsoft Academic Search

    Hamidreza Zareipoura; Kankar Bhattacharya; Claudio A. Canizares

    Price volatility analysis has been reported in the literature for most competitive electricity markets around the world. However, no studies have been published yet that quantify price volatility in the Ontario electricity market, which is the focus of the present paper. In this paper, a comparative volatility analysis is conducted for the Ontario market and its neighboring electricity markets. Volatility

  3. Potential for Measurement of Trace Volatile Organic Compounds in Closed Environments Using Gas Chromatograph/Differential Mobility Spectrometer

    NASA Technical Reports Server (NTRS)

    Limero, Thomas; Cheng, Patti

    2007-01-01

    For nearly 3.5 years, the Volatile Organic Analyzer (VOA) has routinely analyzed the International Space Station (ISS) atmosphere for a target list of approximately 20 volatile organic compounds (VOCs). Additionally, an early prototype of the VOA collected data aboard submarines in two separate trials. Comparison of the data collected on ISS and submarines showed a surprising similarity in the atmospheres of the two environments. Furthermore, in both cases it was demonstrated that the VOA data can detect hardware issues unrelated to crew health. Finally, it was also clear in both operations that the VOA s size and resource consumption were major disadvantages that would restrict its use in the future. The VOA showed the value of measuring VOCs in closed environments, but it had to be shrunk if it was to be considered for future operations in these environments that are characterized by cramped spaces and limited resources. The Sionex Microanalyzer is a fraction of the VOA s size and this instrument seems capable of maintaining or improving upon the analytical performance of the VOA. The two design improvements that led to a smaller, less complex instrument are the Microanalyzer s use of recirculated air as the gas chromatograph s carrier gas and a micromachined detector. Although the VOA s ion mobility spectrometer and the Microanalyzer s differential mobility spectrometer (DMS) are related detector technologies, the DMS was more amenable to micromachining. This paper will present data from the initial assessment of the Microanalyzer. The instrument was challenged with mixtures that simulated the VOCs typically detected in closed-environment atmospheres.

  4. Realized Stock Volatility 2.1 Introduction

    E-print Network

    Niebur, Ernst

    to disappear (the 5 #12;volatility clustering and leverage effect, for instance). On the other hand, if only. Specifically, we use the transaction record of the Dow Jones Industrials Average (DJIA) portfolio over

  5. VOLATILE ORGANIC ANALYSIS BY DIRECT AQUEOUS INJECTION

    EPA Science Inventory

    Gas chromatographic environmental analysis by direct aqueous injection (DAI) was studied for 24 volatile organic analytes (VOAs). Internal standardization was used to determine the precision of analyzing these compounds by DAI. Aequous samples were directly introduced to a gas ch...

  6. TOXIC ORGANIC VOLATILIZATION FROM LAND TREATMENT SYSTEMS

    EPA Science Inventory

    Methodology was evaluated for estimating volatilization of toxic organic chemicals from unsaturated soils. Projections were compared with laboratory data for simulated rapid infiltration wastewater treatment systems receiving primary municipal wastewater spiked with a suite of 18...

  7. VOLATILE ORGANIC COMPOUNDS AS EXPOSURE BIOMARKERS

    EPA Science Inventory

    Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the US Environmental Protection Agency's National Exposure Research Laboratory have developed and refined...

  8. The effect of chemical dispersants on the solution of volatile liquid hydrocarbons from spilled crude oil

    E-print Network

    McDonald, Thomas Joseph

    1982-01-01

    THE EFFECT OF CHEMICAL DISPERSANTS ON THE SOLUTION OF VOLATILE LIQUID HYDROCARBONS FROM SPILLED CRUDE OIL A Thesis by THOMAS JOSEPH McDONALD Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1982 Major Subject: Oceanography THE EFFECT OF CHEMICAL DISPERSANTS ON THE SOLUTION OF VOLATILE LIQUID HYDROCARBONS FROM SPILLED CRUDE OIL A Thesis by THOMAS JOSEPH McDONALD Approved as to style and content by...

  9. Prediction of stream volatilization coefficients

    USGS Publications Warehouse

    Rathbun, Ronald E.

    1990-01-01

    Equations are developed for predicting the liquid-film and gas-film reference-substance parameters for quantifying volatilization of organic solutes from streams. Molecular weight and molecular-diffusion coefficients of the solute are used as correlating parameters. Equations for predicting molecular-diffusion coefficients of organic solutes in water and air are developed, with molecular weight and molal volume as parameters. Mean absolute errors of prediction for diffusion coefficients in water are 9.97% for the molecular-weight equation, 6.45% for the molal-volume equation. The mean absolute error for the diffusion coefficient in air is 5.79% for the molal-volume equation. Molecular weight is not a satisfactory correlating parameter for diffusion in air because two equations are necessary to describe the values in the data set. The best predictive equation for the liquid-film reference-substance parameter has a mean absolute error of 5.74%, with molal volume as the correlating parameter. The best equation for the gas-film parameter has a mean absolute error of 7.80%, with molecular weight as the correlating parameter.

  10. Enhanced life ion source for germanium and carbon ion implantation

    SciTech Connect

    Hsieh, Tseh-Jen; Colvin, Neil; Kondratenko, Serguei [Axcelis Technologies, Inc. 108 Cherry Hill Drive, Beverly, MA 01915 (United States)

    2012-11-06

    Germanium and carbon ions represent a significant portion of total ion implantation steps in the process flow. Very often ion source materials that used to produce ions are chemically aggressive, especially at higher temperatures, and result in fast ion source performance degradation and a very limited lifetime [B.S. Freer, et. al., 2002 14th Intl. Conf. on Ion Implantation Technology Proc, IEEE Conf. Proc., p. 420 (2003)]. GeF{sub 4} and CO{sub 2} are commonly used to generate germanium and carbon beams. In the case of GeF{sub 4} controlling the tungsten deposition due to the de-composition of WF{sub 6} (halogen cycle) is critical to ion source life. With CO{sub 2}, the materials oxidation and carbon deposition must be controlled as both will affect cathode thermionic emission and anti-cathode (repeller) efficiencies due to the formation of volatile metal oxides. The improved ion source design Extended Life Source 3 (Eterna ELS3) together with its proprietary co-gas material implementation has demonstrated >300 hours of stable continuous operation when using carbon and germanium ion beams. Optimizing cogas chemistries retard the cathode erosion rate for germanium and carbon minimizes the adverse effects of oxygen when reducing gas is introduced for carbon. The proprietary combination of hardware and co-gas has improved source stability and the results of the hardware and co-gas development are discussed.

  11. Comparison of extraction methods and detection systems in the gas chromatographic analysis of volatile carbonyl compounds

    Microsoft Academic Search

    Elena E. Stashenko; María Constanza Ferreira; Luis Gonzalo Sequeda; Jairo René Martínez; Jon W. Wong

    1997-01-01

    High-resolution gas chromatography (HRGC) with electron-capture detection (ECD), nitrogen-phosphorus detection (NPD), flame ionization detection (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carbonyl compounds that are typically produced during lipid peroxidation were derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hydrazones. These derivatives were extracted

  12. Ab initio modelling of volatile fission products in uranium mononitride

    NASA Astrophysics Data System (ADS)

    Klipfel, M.; Van Uffelen, P.

    2012-03-01

    Defects and the incorporation of volatile fission products (xenon, krypton, caesium and iodine) in uranium mononitride are investigated using DFT calculations. Various locations for impurities are considered including at a tetrahedral interstitial position, substitution of a host nitrogen or uranium ion and placed in a Schottky defect (UN bivacancy). The incorporation is energetically more favourable for the latter, although the incorporation energies are positive. The preferred position for volatile fission products in UN is at the larger of the vacancies, either a single uranium vacancy or the uranium vacancy of a Schottky defect. The incorporation of a fission product in a bound [1 0 0]-Schottky defect leads to a tetragonal distortion of the supercell. The impurities considered in this work produce very small perturbations of the crystalline matrix of UN. With the exception of impurities at the interstitial site, which perturb the structure into the second coordination sphere, only the displacement of the atoms at the nearest-neighbour positions is significant. Analysis of the charge distribution after incorporation of the fission product reveals a weak charge transfer for the noble gases, while a larger transfer is displayed for caesium and iodine.

  13. Market volatility modeling for short time window

    NASA Astrophysics Data System (ADS)

    de Mattos Neto, Paulo S. G.; Silva, David A.; Ferreira, Tiago A. E.; Cavalcanti, George D. C.

    2011-10-01

    The gain or loss of an investment can be defined by the movement of the market. This movement can be estimated by the difference between the magnitudes of two stock prices in distinct periods and this difference can be used to calculate the volatility of the markets. The volatility characterizes the sensitivity of a market change in the world economy. Traditionally, the probability density function (pdf) of the movement of the markets is analyzed by using power laws. The contributions of this work is two-fold: (i) an analysis of the volatility dynamic of the world market indexes is performed by using a two-year window time data. In this case, the experiments show that the pdf of the volatility is better fitted by exponential function than power laws, in all range of pdf; (ii) after that, we investigate a relationship between the volatility of the markets and the coefficient of the exponential function based on the Maxwell-Boltzmann ideal gas theory. The results show an inverse relationship between the volatility and the coefficient of the exponential function. This information can be used, for example, to predict the future behavior of the markets or to cluster the markets in order to analyze economic patterns.

  14. Scaling properties of foreign exchange volatility

    NASA Astrophysics Data System (ADS)

    Gençay, Ramazan; Selçuk, Faruk; Whitcher, Brandon

    2001-01-01

    In this paper, we investigate the scaling properties of foreign exchange volatility. Our methodology is based on a wavelet multi-scaling approach which decomposes the variance of a time series and the covariance between two time series on a scale by scale basis through the application of a discrete wavelet transformation. It is shown that foreign exchange rate volatilities follow different scaling laws at different horizons. Particularly, there is a smaller degree of persistence in intra-day volatility as compared to volatility at one day and higher scales. Therefore, a common practice in the risk management industry to convert risk measures calculated at shorter horizons into longer horizons through a global scaling parameter may not be appropriate. This paper also demonstrates that correlation between the foreign exchange volatilities is the lowest at the intra-day scales but exhibits a gradual increase up to a daily scale. The correlation coefficient stabilizes at scales one day and higher. Therefore, the benefit of currency diversification is the greatest at the intra-day scales and diminishes gradually at higher scales (lower frequencies). The wavelet cross-correlation analysis also indicates that the association between two volatilities is stronger at lower frequencies.

  15. Stripper-reactor for volatile cobalt recovery

    SciTech Connect

    Nadler, K.C.; Broussard, T.R.; Pitre, J.K.

    1993-08-10

    A method is described for removing cobalt values from the crude product of a cobalt-catalyzed hydroformylation reaction which comprises: (a) contacting said crude product in a stripper-reactor with a stream of stripping gas in the presence of water and an organic acid to entrain volatile cobalt carbonyl in said stripping gas, whereby said entrained volatile cobalt carbonyl are taken out overhead and organic hydroformylation reaction products and water containing water soluble cobaltous salts are taken out as bottoms; (b) withdrawing said organic hydroformulation reaction products and said water containing water soluble cobaltous salts from said stripper-reactor; (c) withdrawing the stripping gas with said entrained volatile cobalt carbonyl from said stripper-reactor; (d) refluxing the withdrawn stripping gas with said entrained volatile cobalt carbonyl thereby producing a concentrated volatile cobalt carbonyl and a reflux product; (e) withdrawing said concentrated volatile cobalt carbonyl from the reflux means; and (f) recycling said reflux product to a location on said stripperreactor which is capable of forming a stripping zone in the upper portion of said stripper-reactor and a reaction zone in the lower portion of said stripper-reactor.

  16. Volatilization and recovery of mercury from mercury wastewater produced in the course of laboratory work using Acidithiobacillus ferrooxidans SUG 2-2 cells

    Microsoft Academic Search

    Fumiaki Takeuchi; Atsunori Negishi; Terunobu Maeda; Kazuo Kamimura; Tsuyoshi Sugio

    2003-01-01

    The iron-oxidizing bacterium Acidithiobacillus ferrooxidans SUG 2-2 is markedly resistant to mercuric chloride and can volatilize mercury (Hg0) from mercuric ion (Hg2+) under acidic conditions. To develop a microbial technique to volatilize and recover mercury from acidic and organic compound-containing mercury wastewater, which is usually produced in the course of everyday laboratory work in Okayama University, the effects of organic

  17. On the pricing and hedging of volatility derivatives

    Microsoft Academic Search

    Sam Howison; Avraam Rafailidis; Henrik Rasmussen

    2004-01-01

    The paper considers the pricing of a range of volatility derivatives, including volatility and variance swaps and swaptions. Under risk-neutral valuation closed-form formulae for volatility-average and variance swaps for a variety of diffusion and jump-diffusion models for volatility are provided. A general partial differential equation framework for derivatives that have an extra dependence on an average of the volatility is

  18. Novel application for ion mobility spectrometry: diagnosing vaginal infections through measurement of biogenic amines

    Microsoft Academic Search

    Zeev Karpas; Walter Chaim; Rachel Gdalevsky; Boris Tilman; Avi Lorber

    2002-01-01

    A method for diagnosis of bacterial vaginosis (BV) and other vaginal infections, based on measurement of biogenic amines present in a sample of vaginal fluid by ion mobility spectrometry (IMS) was developed. Sample introduction is through a two step procedure: addition of alkaline solution to release the volatile amines followed by heating and acid addition for emanation of the semi-volatile

  19. Analysis of roasted and unroasted Pistacia terebinthus volatiles using direct thermal desorption-GCxGC-TOF/MS.

    PubMed

    Gogus, F; Ozel, M Z; Kocak, D; Hamilton, J F; Lewis, A C

    2011-12-01

    The objective of this study was to determine the effects of roasting time on volatile components of Pistacia terebinthus L., a fruit growing wild in Turkey. The whole fruit samples were pan roasted for 0, 5, 10, 15, 20 and 25min at 200°C. Volatile compounds were isolated and identified using the direct thermal desorption (DTD) method coupled with comprehensive gas chromatography - time of flight mass spectrometry (GCxGC-TOF/MS). The major components of the fresh hull of P. terebinthus were ?-pinene (10.37%), limonene (8.93%), ?-pinene (5.53%), 2-carene (4.47%) and ?-muurolene (4.29%). Eighty-three constituents were characterised from the volatiles of fresh whole P. terebinthus fruits obtained by direct thermal desorption with ?-pinene (9.62%), limonene (5.54%), ?-cadinane (5.48%), ?-pinene (5.46%), ?-caryophyllene (5.24%) being the major constituents. The type and the number of constituents characterised were observed to change with differing roasting times. Limonene (5.56%), ?-pinene (4.84%), 5-methylfurfural (4.78%), 5-hydroxymethylfurfural (5-HMF, 3.89%), dimethylmetoxyfuranone (3.67%) and 3-methyl-2(5H)furanone (3.12%) were identified as the major components among the 104 compounds characterised in the volatiles of P. terebinthus, roasted for 25min. In addition, volatiles of fully roasted P. terebinthus fruits contained furans and furanones (15.42%), pyridines (4.45%) and benzene derivatives (3.81%) as the major groups. PMID:25212365

  20. Attraction of Spodoptera frugiperda larvae to volatiles from herbivore-damaged maize seedlings.

    PubMed

    Carroll, Mark J; Schmelz, Eric A; Meagher, Robert L; Teal, Peter E A

    2006-09-01

    Plants respond to insect attack with the induction of volatiles that function as indirect plant defenses through the attraction of natural enemies to the herbivores. Despite the fact that volatiles are induced in response to caterpillar attack, their reciprocal effects on the host location behaviors of the same foraging herbivores are poorly understood. We examined orientation responses of sixth instar fall armyworm [FAW; Spodoptera frugiperda (Smith)] to odors from herbivore-damaged and undamaged maize seedlings (Zea mays var. Golden Queen) in y-tube olfactometer bioassays. While both damaged and undamaged maize seedlings were attractive compared with air, sixth instars preferred odors from damaged maize seedlings over odors from undamaged maize seedlings. Gas chromatography-mass spectrometry analysis of plant volatiles revealed that linalool and 4,8-dimethyl-1,3,7-nonatriene were the major volatiles induced by FAW herbivory 6 hr after initial damage. Given its prominence in induced plants and established attractiveness to adult FAW, linalool was evaluated both as an individual attractant and as a supplemental component of whole plant odors. Volatile linalool was more attractive than air to sixth instar FAW over a broad range of release rates. FAW also responded selectively to different amounts of linalool, preferring the higher amount. The orientation preferences of FAW were readily manipulated through capillary release of linalool into the airstream of whole plant odors. FAW preferred linalool over undamaged plant odors, and linalool-supplemented plant odors over unsupplemented plant odors, indicating that olfactory preferences could be changed by alteration of a single volatile component. These results suggest that although many induced volatiles attract natural enemies of herbivores, these defenses may also inadvertently recruit more larval herbivores to an attacked plant or neighboring conspecifics. PMID:16902828

  1. Aroma profile and volatiles odor activity along gold cultivar pineapple flesh.

    PubMed

    Montero-Calderón, Marta; Rojas-Graü, María Alejandra; Martín-Belloso, Olga

    2010-01-01

    Physicochemical attributes, aroma profile, and odor contribution of pineapple flesh were studied for the top, middle, and bottom cross-sections cut along the central axis of Gold cultivar pineapple. Relationships between volatile and nonvolatile compounds were also studied. Aroma profile constituents were determined by headspace solid-phase microextraction at 30 °C, followed by gas chromatography/mass spectrometry analysis. A total of 20 volatile compounds were identified and quantified. Among them, esters were the major components which accounted for 90% of total extracted aroma. Methyl butanoate, methyl 2-methyl butanoate, and methyl hexanoate were the 3 most abundant components representing 74% of total volatiles in pineapple samples. Most odor active contributors were methyl and ethyl 2-methyl butanoate and 2,5-dimethyl 4-methoxy 3(2H)-furanone (mesifuran). Aroma profile components did not vary along the fruit, but volatile compounds content significantly varied (P < 0.05) along the fruit, from 7560 to 10910 ?g/kg, from the top to the bottom cross-sections of the fruit, respectively. In addition, most odor-active volatiles concentration increased from the top to the bottom 3rd of the fruit, concurrently with soluble solids content (SSC) and titratable acidity (TA) differences attributed to fruitlets distinct degree of ripening. Large changes in SSC/TA ratio and volatiles content throughout the fruit found through this study are likely to provoke important differences among individual fresh-cut pineapple trays, compromising consumer perception and acceptance of the product. Such finding highlighted the need to include volatiles content and SSC/TA ratio and their variability along the fruit as selection criteria for pineapples to be processed and quality assessment of the fresh-cut fruit. PMID:21535624

  2. Olfactory responses of banana weevil predators to volatiles from banana pseudostem tissue and synthetic pheromone.

    PubMed

    Tinzaara, W; Gold, C S; Dicke, M; van Huis, A

    2005-07-01

    As a response to attack by herbivores, plants can emit a variety of volatile substances that attract natural enemies of these insect pests. Predators of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) such as Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae), are normally found in association with weevil-infested rotten pseudostems and harvested stumps. We investigated whether these predators are attracted to such environments in response to volatiles produced by the host plant, by the weevil, or by the weevil plant complex. We evaluated predator responses towards volatiles from banana pseudostem tissue (synomones) and the synthetic banana weevil aggregation pheromone Cosmolure+ in a two-choice olfactometer. The beetle D. abdominale was attracted to fermenting banana pseudostem tissue and Cosmolure+, whereas the ant P. megacephala was attracted only to fermented pseudostem tissue. Both predators were attracted to banana pseudostem tissue that had been damaged by weevil larvae irrespective of weevil presence. Adding pheromone did not enhance predator response to volatiles from pseudostem tissue fed on by weevils. The numbers of both predators recovered with pseudostem traps in the field from banana mats with a pheromone trap were similar to those in pseudostem traps at different distance ranges from the pheromone. Our study shows that the generalist predators D. abdominale and P. megacephala use volatiles from fermented banana pseudostem tissue as the major chemical cue when searching for prey. PMID:16222791

  3. Volatile-bearing phases in carbonaceous chondrites: Compositions, modal abundance, and reaction kinetics

    NASA Technical Reports Server (NTRS)

    Ganguly, Jibamitra

    1990-01-01

    The spectral and density characteristics of Phobos and Deimos (the two small natural satellites of Mars) strongly suggest that a significant fraction of the near-earth asteroids are made of carbonaceous chondrites, which are rich in volatile components and, thus, could serve as potential resources for propellants and life supporting systems in future planetary missions. However, in order to develop energy efficient engineering designs for the extraction of volatiles, knowledge of the nature and modal abundance of the minerals in which the volatiles are structurally bound and appropriate kinetic data on the rates of the devolatilization reactions is required. Theoretical calculations to predict the modal abundances and compositions of the major volatile-bearing and other mineral phases that could develop in the bulk compositions of C1 and C2 classes (the most volatile rich classes among the carbonaceous chondrites) were performed as functions of pressure and temperature. The rates of dehydration of talc at 585, 600, 637, and 670 C at P(total) = 1 bar were determine for the reaction: Talc = 3 enstatite + quartz + water. A scanning electron microscopic study was conducted to see if the relative abundance of phases can be determined on the basis of the spectral identification and x ray mapping. The results of this study and the other studies within the project are discussed.

  4. Trophic complexity and the adaptive value of damage-induced plant volatiles.

    PubMed

    Kaplan, Ian

    2012-01-01

    Indirect plant defenses are those facilitating the action of carnivores in ridding plants of their herbivorous consumers, as opposed to directly poisoning or repelling them. Of the numerous and diverse indirect defensive strategies employed by plants, inducible volatile production has garnered the most fascination among plant-insect ecologists. These volatile chemicals are emitted in response to feeding by herbivorous arthropods and serve to guide predators and parasitic wasps to their prey. Implicit in virtually all discussions of plant volatile-carnivore interactions is the premise that plants "call for help" to bodyguards that serve to boost plant fitness by limiting herbivore damage. This, by necessity, assumes a three-trophic level food chain where carnivores benefit plants, a theoretical framework that is conceptually tractable and convenient, but poorly depicts the complexity of food-web dynamics occurring in real communities. Recent work suggests that hyperparasitoids, top consumers acting from the fourth trophic level, exploit the same plant volatile cues used by third trophic level carnivores. Further, hyperparasitoids shift their foraging preferences, specifically cueing in to the odor profile of a plant being damaged by a parasitized herbivore that contains their host compared with damage from an unparasitized herbivore. If this outcome is broadly representative of plant-insect food webs at large, it suggests that damage-induced volatiles may not always be beneficial to plants with major implications for the evolution of anti-herbivore defense and manipulating plant traits to improve biological control in agricultural crops. PMID:23209381

  5. A volatile relationship: profiling an inter-kingdom dialogue between two plant pathogens, Ralstonia Solanacearum and Aspergillus Flavus.

    PubMed

    Spraker, Joseph E; Jewell, Kelsea; Roze, Ludmila V; Scherf, Jacob; Ndagano, Dora; Beaudry, Randolph; Linz, John E; Allen, Caitilyn; Keller, Nancy P

    2014-05-01

    Microbes in the rhizosphere have a suite of extracellular compounds, both primary and secondary, that communicate with other organisms in their immediate environment. Here, we describe a two-way volatile interaction between two widespread and economically important soil-borne pathogens of peanut, Aspergillus flavus and Ralstonia solanacearum, a fungus and bacterium, respectively. In response to A. flavus volatiles, R. solanacearum reduced production of the major virulence factor extracellular polysaccharide (EPS). In parallel, A. flavus responded to R. solanacearum volatiles by reducing conidia production, both on plates and on peanut seeds and by increasing aflatoxin production on peanut. Volatile profiling of these organisms using solid-phase micro-extraction gas chromatography mass spectroscopy (SPME-GCMS) provided a first glimpse at the compounds that may drive these interactions. PMID:24801606

  6. Ion source

    DOEpatents

    Leung, Ka-Ngo (Hercules, CA); Ehlers, Kenneth W. (Alamo, CA)

    1984-01-01

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

  7. Volatile Organic Compound Analysis in Istanbul

    NASA Astrophysics Data System (ADS)

    ?apraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Co?kun, M.

    2012-04-01

    Volatile Organic Compound Analysis in Istanbul Ö. Çapraz1, A. Deniz1,3, A. Ozturk2, S. Incecik1, H. Toros1 and, M. Coskun1 (1) Istanbul Technical University, Faculty of Aeronautics and Astronautics, Department of Meteorology, 34469, Maslak, Istanbul, Turkey. (2) Istanbul Technical University, Faculty of Chemical and Metallurgical, Chemical Engineering, 34469, Maslak, Istanbul, Turkey. (3) Marmara Clean Air Center, Ministry of Environment and Urbanization, Ni?anta??, 34365, ?stanbul, Turkey. One of the major problems of megacities is air pollution. Therefore, investigations of air quality are increasing and supported by many institutions in recent years. Air pollution in Istanbul contains many components that originate from a wide range of industrial, heating, motor vehicle, and natural emissions sources. VOC, originating mainly from automobile exhaust, secondhand smoke and building materials, are one of these compounds containing some thousands of chemicals. In spite of the risks to human health, relatively little is known about the levels of VOC in Istanbul. In this study, ambient air quality measurements of 32 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in Ka??thane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Ka??thane creek valley is the source part of the Golden Horn and one of the most polluted locations in Istanbul due to its topographical form and pollutant sources in the region. In this valley, horizontal and vertical atmospheric motions are very weak. The target compounds most commonly found were benzene, toluene, xylene and ethyl benzene. Concentrations of total hydrocarbons ranged between 1.0 and 10.0 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations and no single factor seemed to explain trends for this group of compounds. N-octane, 3-methylheptane, n-nonane, 2,3,4-trimethylpentane and n-hexane parameters ranged between 3 ppbv and maximum value of 10 ppbv. The other VOC parameters are measured below 3 ppbv value. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly in?uence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde. Keywords: Air quality, Volatile Organic Compounds (VOC), industry, meteorology, urban, Ka??thane, ?stanbul. Acknowledgment: This work was part of the TUJJB-TUMEHAP-01-10 and Turkish Scientific and Technical Research Council Project No: 109Y132.

  8. Attraction of pea moth Cydia nigricana to pea flower volatiles.

    PubMed

    Thöming, Gunda; Knudsen, Geir K

    2014-04-01

    The pea moth Cydia nigricana causes major crop losses in pea (Pisum sativum) production. We investigated attraction of C. nigricana females to synthetic pea flower volatiles in a wind tunnel and in the field. We performed electroantennogram analysis on 27 previously identified pea plant volatiles, which confirmed antennal responses to nine of the compounds identified in pea flowers. A dose-dependent response was found to eight of the compounds. Various blends of the nine pea flower volatiles eliciting antennal responses were subsequently studied in a wind tunnel. A four-compound blend comprising hexan-1-ol, (E)-2-hexen-1-ol, (Z)-?-ocimene and (E)-?-ocimene was equally attractive to mated C. nigricana females as the full pea flower mimic blend. We conducted wind-tunnel tests on different blends of these four pea flower compounds mixed with a headspace sample of non-flowering pea plants. By considering the effects of such green leaf background odour, we were able to identify (Z)- and (E)-?-ocimene as fundamental for host location by the pea moths, and hexan-1-ol and (E)-2-hexen-1-ol as being of secondary importance in that context. In the field, the two isomers of ?-ocimene resulted in trap catches similar to those obtained with the full pea flower mimic and the four-compound blend, which clearly demonstrated the prime significance of the ?-ocimenes as attractants of C. nigricana. The high level of the trap catches of female C. nigricana noted in this first field experiment gives a first indication of the potential use of such artificial kairomones in pea moth control. PMID:24508043

  9. 77 FR 52606 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Volatile Organic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ...recordkeeping requirements, Volatile organic compounds. Dated: August 14, 2012...new entry in ``Article 8. Volatile Organic Compound Rules'' for ``Rule 14. Architectural...Article 8. Volatile Organic Compound...

  10. Majority Gate Networks

    Microsoft Academic Search

    S. Amarel; G. Cooke; R. O. Winder

    1964-01-01

    This paper presents methods for realizing simple threshold functions of n arguments by networks of k-input majority gates, where k?n. An optimal network realization of the 5-argument majority function using 3-input majority gates is given, and it is then generalized by steps with realizations for the (2n-l)-argument majority function (where n = 3, 4, ...) using (2n-3)-input majority gates, and

  11. Negative ions

    Microsoft Academic Search

    H. Massey

    1976-01-01

    Topics covered include: the negative ion of hydrogen; ground states of complex atomic negative ions-theoretical considerations; the electron affinities of the elements; atomic negative ions-excited states-autodetachment, general account; autodetaching states of specific atomic negative ions; molecular negative ions-ground states; excited electronic states of molecular negative ions; modes of formation of negative ions-formation by radiative processes-radiative attachment and polar photodissociation; modes

  12. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-02-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  13. Reactive oxidation products promote secondary organic aerosol formation from green leaf volatiles

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Lewis, A. C.; Carey, T. J.; Wenger, J. C.; Garcia, E. Borrás. I.; Muñoz, A.

    2009-06-01

    Green leaf volatiles (GLVs) are an important group of chemicals released by vegetation which have emission fluxes that can be significantly increased when plants are damaged or stressed. A series of simulation chamber experiments has been conducted at the European Photoreactor in Valencia, Spain, to investigate secondary organic aerosol (SOA) formation from the atmospheric oxidation of the major GLVs cis-3-hexenylacetate and cis-3-hexen-1-ol. Liquid chromatography-ion trap mass spectrometry was used to identify chemical species present in the SOA. Cis-3-hexen-1-ol proved to be a more efficient SOA precursor due to the high reactivity of its first generation oxidation product, 3-hydroxypropanal, which can hydrate and undergo further reactions with other aldehydes resulting in SOA dominated by higher molecular weight oligomers. The lower SOA yields produced from cis-3-hexenylacetate are attributed to the acetate functionality, which inhibits oligomer formation in the particle phase. Based on observed SOA yields and best estimates of global emissions, these compounds may be calculated to be a substantial unidentified global source of SOA, contributing 1-5 TgC yr-1, equivalent to around a third of that predicted from isoprene. Molecular characterization of the SOA, combined with organic mechanistic information, has provided evidence that the formation of organic aerosols from GLVs is closely related to the reactivity of their first generation atmospheric oxidation products, and indicates that this may be a simple parameter that could be used in assessing the aerosol formation potential for other unstudied organic compounds in the atmosphere.

  14. Clustering of volatility in variable diffusion processes

    NASA Astrophysics Data System (ADS)

    Gunaratne, Gemunu H.; Nicol, Matthew; Seemann, Lars; Török, Andrei

    2009-10-01

    Increments in financial markets have anomalous statistical properties including fat-tailed distributions and volatility clustering (i.e., the autocorrelation functions of return increments decay quickly but those of the squared increments decay slowly). One of the central questions in financial market analysis is whether the nature of the underlying stochastic process can be deduced from these statistical properties. We have shown previously that a class of variable diffusion processes has fat-tailed distributions. Here we show analytically that such models also exhibit volatility clustering. To our knowledge, this is the first case where clustering of volatility is proven analytically in a model. Our results are compatible with the viewpoint that variable diffusion processes are possible models for financial markets.

  15. Volatile components and continental material of planets

    NASA Technical Reports Server (NTRS)

    Florenskiy, K. P.; Nikolayeva, O. V.

    1986-01-01

    It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H20, CO2, etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes.

  16. Volatile compounds in shergottite and nakhlite meteorites

    NASA Technical Reports Server (NTRS)

    Gooding, James L.; Aggrey, Kwesi E.; Muenow, David W.

    1990-01-01

    Since discovery of apparent carbonate carbon in Nakhla, significant evidence has accumulated for occurrence of volatile compounds in shergotties and nakhlites. Results are presented from a study of volatile compounds in three shergottites, one nakhlite, and three eucrite control samples. Shergotties ALHA77005, EETA79001, and Shergotty, and the nakhlite Nakhla, all contain oxidized sulfur (sulfate) of preterrestrial origin; sulfur oxidation is most complete in EETA79001/Lith-C. Significant bulk carbonate was confirmed in Nakhla and trace carbonate was substantiated for EETA79001, all of which appears to be preterrestrial in origin. Chlorine covaries with oxidized sulfur, whereas carbonate and sulfate are inversely related. These volatile compounds were probably formed in a highly oxidizing, aqueous environment sometime in the late stage histories of the rocks that are now represented as meteorites. They are consistent with the hypothesis that shergottite and nakhlite meteorites originated on Mars and that Mars has supported aqueous geochemistry during its history.

  17. Volatile Species Retention During Metallic Fuel Casting

    SciTech Connect

    Randall S. Fielding; Douglas L. Proter

    2013-10-01

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, although the loss values varied from the model results the same trend was seen. Bases on these results it is very probably that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  18. Volatile species retention during metallic fuel casting

    NASA Astrophysics Data System (ADS)

    Fielding, Randall S.; Porter, Douglas L.

    2013-10-01

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, and although the loss values varied from the model results the same trend was seen. Based on these results it is very probable that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  19. Analyzing method on biogenic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Bai, J. H.; Wang, M. X.; Hu, F.; Greenberg, J. P.; Guenther, A. B.

    2002-02-01

    In order to analyze biogenic volatile organic compounds in the atmosphere, an automated gas chromatography is developed and employed at the laboratory of National Center for Atmospheric Research (NCAR) during January to July, 2000. A small refrigerator was used so as to remove water in the air sample from gas line, and get accurate concentrations of volatile organic compounds. At 5degreesC, good water removing efficiency can be obtained at controlled flow rate. Air samples were collected around the building of Mesa Lab. of NCAR and analyzed by this gas chromatography system. This paper reports this gas chromatography system and results of air samples. The experimental results show that this gas chromatography system has a good reproducibility and stability, and main interesting volatile organic compounds such as isoprene, monoterpenes have an evident diurnal variation.

  20. Catalyst for Oxidation of Volatile Organic Compounds

    NASA Technical Reports Server (NTRS)

    Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

    2000-01-01

    Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  1. Volatiles of Curcuma mangga Val. & Zijp (Zingiberaceae) from Malaysia.

    PubMed

    Wahab, Ikarastika Rahayu Abdul; Blagojevi?, Polina D; Radulovi?, Niko S; Boylan, Fabio

    2011-11-01

    Analysis by GC and GC/MS of the essential oil obtained from Malaysian Curcuma mangga Val. & Zijp (Zingiberaceae) rhizomes allowed the identification of 97 constituents, comprising 89.5% of the total oil composition. The major compounds were identified as myrcene (1; 46.5%) and ?-pinene (2; 14.6%). The chemical composition of this and additional 13 oils obtained from selected Curcuma L. taxa were compared using multivariate statistical analyses (agglomerative hierarchical cluster analysis and principal component analysis). The results of the statistical analyses of this particular data set pointed out that 1 could be potentially used as a valuable infrageneric chemotaxonomical marker for C. mangga. Moreover, it seems that C. mangga, C. xanthorrhiza Roxb., and C. longa L. are, with respect to the volatile secondary metabolites, closely related. In addition, comparison of the essential oil profiles revealed a potential influence of the environmental (geographical) factors, alongside with the genetic ones, on the production of volatile secondary metabolites in Curcuma taxa. PMID:22083913

  2. Volatile organic compounds from a Tuber melanosporum fermentation system.

    PubMed

    Li, Yuan-Yuan; Wang, Guan; Li, Hong-Mei; Zhong, Jian-Jiang; Tang, Ya-Jie

    2012-12-15

    A total of 59 volatile organic compounds (VOCs) were identified from Tuber melanosporum fermentation: 53 from its fermented mycelia and 32 from the fermentation broth. Alcohol-derived compounds were predominant in both the fermentation mycelia and the broth, although long chain fatty acids and isoprenoids were, for the first time, also found in the mycelia. The intense wine bouquet properties of the broth arose from several specific flavor substances, including sulfur compounds, pyrazines, furans and jasmones. Comparing the VOCs identified in this work with those previously reported, our results are more similar to the composition of the Tuber fruiting-body than previous Tuber fermentations. The composition and accumulation of flavor volatiles (e.g., pyrazines, sulfur compounds, and esters) and major constituents (e.g., 3-methyl-1-butanol and 2-phenylethanol) in this fermentation were significantly influenced by the sucrose concentration in the medium. The obtained information could therefore be useful in applications to convert the flavors of truffle mycelia similar to those of the fruiting-body by optimising the fermentation process. PMID:22980851

  3. Space-weathering processes and products on volatile-rich asteroids

    NASA Astrophysics Data System (ADS)

    Britt, D.; Schelling, P.; Consolmagno, G.; Bradley, T.

    2014-07-01

    Space weathering is a generic term for the effects on atmosphereless solid bodies in the solar system from a range of processes associated with direct exposure to the space environment. These include impact processes (shock, vaporization, fragmentation, heating, melting, and ejecta formation), radiation damage (from galactic and solar cosmic rays), solar-wind effects (irradiation, ion implantation, and sputtering), and the chemical reactions driven by these processes. The classic example of space weathering is the formation of the lunar spectral red slope associated with the production of nanophase Fe (npFe0) in the dusty lunar regolith (C.R. Chapman, 2004, Annual Review of Earth & Planet. Sci. 32, C.M. Pieters, 2000, MAPS 35). Similar npFe0 has been recovered from asteroid (25143) Itokawa and some asteroid classes do exhibit modest spectral red slopes (T. Noguchi, 2011, Science 333). Space weathering can be thought of as driven by a combination of the chemical environment of space (hard vacuum, low oxygen fugacity, solar-wind implantation of hydrogen) along with thermal energy supplied by micrometeorite impacts. The forward modeling of space weathering as thermodynamically-driven decomposition of common rock-forming minerals suggests the production of a range of daughter products: (1) The silicate products typically lose oxygen, other volatile elements (i.e., sulfur and sodium), and metallic cations, producing minerals that are typically more disordered and less optically active than the original parent materials. (2) The decomposed metallic cations form in nano-sized blebs including npFe0, on the surfaces or in condensing rims of mineral grains. This creates a powerful optical component as seen in the lunar red slope. Surfaces with exposed npFe0 are an ideal environment for catalyzing further reactions. (3) The liberated volatile elements and gases (O, S, Na) may form an observable exosphere (e.g., Moon and Mercury) and can either escape from the body or recombine with available solar-wind-implanted hydrogen to form trace amounts of water and OH. Mineral decomposition can be thought of as the first stage of space weathering. It produces weathered surfaces somewhat depleted in volatile elements, creates a predictable set of minor or trace minerals, and leaves the surfaces with catalytic species, primarily npFe0. However, a second stage of further reactions and weathering depends upon the presence of ''feed-stock'' components that can participate in catalyzed chemical reactions on exposed surfaces. For volatile-rich small bodies, the available materials are not only silicates, but a volatile feedstock that can include water, carbon monoxide, ammonia, to name a few. Thermodynamically-driven decomposition of silicates will produce trace amounts of npFe0 which are ideal sites for Fischer-Tropsch type (FTT) catalytic reactions that can produce organics in situ on the asteroids including alkanes, polyaromatic hydrocarbons, and amino acids (J.E. Elsila, 2012, MAPS 47). The mix and range of products depends on the composition and morphology of the mineral surface, energy inputs produced by the micrometeorite impacts or other processes, and the composition of the input volatile feedstock. FFT reactions generate long-chain carbon compounds and amino acids. Secondary reactions that generate more complex carbon compounds and amino acids are likely to occur as the organic material matures. Weathering maturity can be thought of as a function of the abundance and diversity of the weathering products. Since the npFe0 is not destroyed in the reaction, continued micrometeorite bombardment would result in continuing processing and recombination of the existing organic feedstock. More weathering would result in progressively longer-chain carbon compounds as well as more complex and diverse amino acids, and eventually the kerogen-like insoluble-organic matter that forms a large fraction of carbonaceous meteorites. This insight has several major implications for our planetary science and, potentially, the formation of the precursors of l

  4. Changes in dark chocolate volatiles during storage.

    PubMed

    Nightingale, Lia M; Cadwallader, Keith R; Engeseth, Nicki J

    2012-05-01

    Chocolate storage is critical to the quality of the final product. Inadequate storage, especially with temperature fluctuations, may lead to a change in crystal structure, which may eventually cause fat bloom. Bloom is the main cause of quality loss in the chocolate industry. The impact of various storage conditions on the flavor quality of dark chocolate was determined. Dark chocolate was stored in different conditions leading to either fat or sugar bloom and analyzed at 0, 4, and 8 weeks of storage. Changes in chocolate flavor were determined by volatile analysis and descriptive sensory evaluation. Results were analyzed by analysis of variance (ANOVA), cluster analysis, principal component analysis (PCA), and linear partial least-squares regression analysis (PLS). Volatile concentration and loss were significantly affected by storage conditions. Chocolates stored at high temperature were the most visually and texturally compromised, but volatile concentrations were affected the least, whereas samples stored at ambient, frozen, and high relative humidity conditions had significant volatile loss during storage. It was determined that high-temperature storage caused a change in crystal state due to the polymorphic shift to form VI, leading to an increase in sample hardness. Decreased solid fat content (SFC) during high-temperature storage increased instrumentally determined volatile retention, although no difference was detected in chocolate flavor during sensory analysis, possibly due to instrumental and sensory sampling techniques. When all instrumental and sensory data had been taken into account, the storage condition that had the least impact on texture, surface roughness, grain size, lipid polymorphism, fat bloom formation, volatile concentrations, and sensory attributes was storage at constant temperature and 75% relative humidity. PMID:22482444

  5. Mercury volatilization from salt marsh sediments

    NASA Astrophysics Data System (ADS)

    Smith, Lora M.; Reinfelder, John R.

    2009-06-01

    In situ volatilization fluxes of gaseous elemental mercury, Hg(0), were estimated for tidally exposed salt marsh sediments in the summer at the urban/industrial Secaucus High School Marsh, New Jersey Meadowlands (Secaucus, New Jersey) and in the early autumn at a regional background site in the Great Bay estuary (Tuckerton, New Jersey). Estimated daytime sediment-air mercury volatilization fluxes at the Secaucus High School Marsh ranged from -375 to +677 ng m-2 h-1 and were positive (land to air flux) in 16 out of 20 measurement events. At the Great Bay estuary, mercury fluxes measured continuously over a 48-h period ranged from -34 to +81 ng m-2 h-1 and were positive during the day and negative at night. At both sites, mercury volatilization fluxes peaked at midday, and cumulative mercury fluxes exhibited strong positive correlations with cumulative solar radiation (r2 = 0.97, p < 0.01) consistent with a light-driven mercury volatilization efficiency of about 15 ng Hg mol PAR-1 or about 0.06 ng Hg kJ-1. No significant correlations were found between mercury fluxes and wind speed, air temperature, or tide height at either site. Thus despite a tenfold difference in sediment mercury concentration, photochemistry appears to be the dominant factor controlling mercury volatilization from these salt marsh sediments. The average mercury volatilization flux estimated for the Great Bay salt marsh in this study (17 ng m-2 h-1) compares well with other micrometeorological mercury fluxes for nonpoint source contaminated salt marsh and forest soils (8-18 ng m-2 h-1) and is more than 10 times higher than the average mercury emission flux from land (˜1 ng m-2 h-1). Annual mercury emissions from salt marsh wetlands may be comparable to individual industrial emissions sources in coastal states of the eastern United States.

  6. Analysis of volatile organic compounds. [trace amounts of organic volatiles in gas samples

    NASA Technical Reports Server (NTRS)

    Zlatkis, A. (inventor)

    1977-01-01

    An apparatus and method are described for reproducibly analyzing trace amounts of a large number of organic volatiles existing in a gas sample. Direct injection of the trapped volatiles into a cryogenic percolum provides a sharply defined plug. Applications of the method include: (1) analyzing the headspace gas of body fluids and comparing a profile of the organic volatiles with standard profiles for the detection and monitoring of disease; (2) analyzing the headspace gas of foods and beverages and comparing the profile with standard profiles to monitor and control flavor and aroma; and (3) analyses for determining the organic pollutants in air or water samples.

  7. Inhibition of volatile compounds derived from fatty acid oxygenation with chilling and heating treatments and their influences on the oxylipin pathawy gene expression and enzyme activity levels in tomato (Solanum lycopersicon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hexanal, Z-3-hexenal, E-2-hexenal, hexanol and Z-3-hexenol are major tomato (Solanum Lycopersicon) volatile aromas derived from oxygenation of unsaturated fatty acids. Chilling or heating treatments suppress production of these C6 volatiles. The objective of this research was to determine the respon...

  8. Major Rock Groups

    NSDL National Science Digital Library

    This resource from the University of Saskatchewan contains general information on the major rock groups: igneous, metamorphic and sedimentary. Describes the rock cycle and the properties and formation of each major rock group.

  9. Dietary exposure to volatile and non-volatile N-nitrosamines from processed meat products in Denmark.

    PubMed

    Herrmann, S S; Duedahl-Olesen, L; Christensen, T; Olesen, P T; Granby, K

    2015-06-01

    Recent epidemiological studies show a positive association between cancer incidence and high intake of processed meat. N-nitrosamines (NAs) in these products have been suggested as one potential causative factor. Most volatile NAs (VNAs) are classified as probable human carcinogens, whereas the carcinogenicity for the majority of the non-volatile NA (NVNA) remains to be elucidated. Danish adults (15-75 years) and children (4-6 years) consume 20?g and 16?g of processed meat per day (95th percentile), respectively. The consumption is primarily accounted for by sausages, salami, pork flank (spiced and boiled) and ham. This consumption results in an exposure to NVNA of 33 and 90?ng kg bw(-1) day(-1) for adults and children, respectively. The exposure to VNA is significantly lower amounting to 0.34 and 1.1?ng kg bw(-1) day(-1) for adults and children, respectively. Based on a BMDL10 of 29?µg kg bw(-1) day(-1) a MOE value ?17,000 was derived for the exposure to NA known to be carcinogenic (VNA including NSAR), indicating an exposure of low concern. The exposure to the NVNA is substantially higher and if found to be of toxicological significance the exposure may be of concern. PMID:25792266

  10. Pre-eruptive volatile and erupted gas phase characterization of the 2014 basalt of Bárðarbunga volcanic system, Iceland.

    NASA Astrophysics Data System (ADS)

    Haddadi, Baptiste; Moune, Séverine; Sigmarsson, Olgeir; Gauthier, Pierre-Jean; Gouhier, Mathieu

    2015-04-01

    The 2014 Holuhraun eruption on the Bárðarbunga Volcanic System is the largest fissure eruption in Iceland since the 1783 Laki eruption. The eruption started end of August 2014 and has been characterized by large emission of SO2 into the atmosphere. It provides a rare opportunity to study in details magmatic and degassing processes during a large-volume fissure eruption. In order to characterize the pre-eruptive magmatic composition and to assess the plume chemistry at the eruption site, lava and tephra were sampled together with the eruption plume. The basalt composition is olivine tholeiite with MgO close to 7 wt%. It is phenocryst-poor with plagioclase as the dominant mineral phase but olivine and clinopyroxene are also present together with sulphide globules composed principally of pyrite and chalcopyrite. The volatile (S, Cl and F) and major element concentrations were measured by the electron microprobe in melt inclusions (MIs) trapped in plagioclase and clinopyroxene and groundmass glass. The MIs composition ranges from fairly primitive basaltic compositions (MgO: 9.03 wt%) down to evolved qz-tholeiites (MgO: 5.57 wt%), with estimated pre-eruptive S concentrations of 1500 ppm. Tephra groundmass glass contains 400 ppm S, whereas Cl and F concentrations are respectively slightly lower and indistinguishable from those in the MIs. This implies limited exsolution of halogens but 75% of the initial sulphur content. Relatively to their total iron content, MIs are sulphur saturated, and their oxygen fugacity close to the FMQ buffer. The difference between the estimated initial volatile concentrations measured in the MIs and in the tephra groundmass (i.e. the so-called petrological method) yields 7.2 Mt SO2, limited HCl and no HF atmospheric mass loading from the Holuhraun 2014 eruption. The SO2/HCl molar ratio of the gas phase, calculated from the MIs, is 13 and 14, respectively, using average and estimated pre-eruptive S and Cl concentrations in the MIs. Filter-pack sampling of the gas plume was performed 2 October 2014 few hundred meters to the W of the active crater row. Filter packs were composed of three filters in series: one PTFE filter to collect particulate phases, followed by two impregnated filters to trap major gaseous species (SO2, HF and HCl). Sulphate (SO4) and halide (Cl- and F-) ion concentrations were determined by ion chromatography. The SO2/HCl molar ratio in the erupted gas phase at the eruption site is 29-46, only slightly higher than that estimated from the MIs. Trace element volatility and fluxes are discussed elsewhere (Gauthier et al., 2015) but the average SO2 flux calculated from lava volume estimate end of November as 1.2 km3 (Gouhier et al., 2015) is close to 1100 kg/sec. This is the highest SO2 flux ever estimated from gas plume measurements. References: Gauthier et al. (2015) Trace element degassing patterns and volcanic fluxes to the atmosphere during the 2014 Holuhraun eruption, Iceland. EGU General Assembly 2015. Gouhier et al. (2015) Retrieval of lava and SO2 long-lived emissions using MSG-SEVIRI data during the 2014 Holuhraun eruption. EGU General Assembly 2015.

  11. Volatile anesthetics inhibit sodium channels without altering bulk lipid bilayer properties

    PubMed Central

    Sanford, R. Lea; Lee, William; Schultz, Margaret F.; Ingólfsson, Helgi I.

    2014-01-01

    Although general anesthetics are clinically important and widely used, their molecular mechanisms of action remain poorly understood. Volatile anesthetics such as isoflurane (ISO) are thought to alter neuronal function by depressing excitatory and facilitating inhibitory neurotransmission through direct interactions with specific protein targets, including voltage-gated sodium channels (Nav). Many anesthetics alter lipid bilayer properties, suggesting that ion channel function might also be altered indirectly through effects on the lipid bilayer. We compared the effects of ISO and of a series of fluorobenzene (FB) model volatile anesthetics on Nav function and lipid bilayer properties. We examined the effects of these agents on Nav in neuronal cells using whole-cell electrophysiology, and on lipid bilayer properties using a gramicidin-based fluorescence assay, which is a functional assay for detecting changes in lipid bilayer properties sensed by a bilayer-spanning ion channel. At clinically relevant concentrations (defined by the minimum alveolar concentration), both the FBs and ISO produced prepulse-dependent inhibition of Nav and shifted the voltage dependence of inactivation toward more hyperpolarized potentials without affecting lipid bilayer properties, as sensed by gramicidin channels. Only at supra-anesthetic (toxic) concentrations did ISO alter lipid bilayer properties. These results suggest that clinically relevant concentrations of volatile anesthetics alter Nav function through direct interactions with the channel protein with little, if any, contribution from changes in bulk lipid bilayer properties. Our findings further suggest that changes in lipid bilayer properties are not involved in clinical anesthesia. PMID:25385786

  12. Information Technology and the Volatility of Firm Performance

    E-print Network

    Hunter, Starling

    2004-03-12

    This study investigates the impact of IT investments and several contextual variables on the volatility of future earnings. We find evidence that IT investments strongly increases the volatility of future earnings and that ...

  13. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  14. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  15. 40 CFR 60.392 - Standards for volatile organic compounds

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Standards for volatile organic compounds 60.392 Section 60...Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations § 60.392 Standards for volatile organic compounds On and after...

  16. Volatile pheromone signalling in Drosophila

    PubMed Central

    Smith, Dean P.

    2013-01-01

    Once captured by the antenna, 11-cis vaccenyl acetate (cVA) binds to an extracellular binding protein called LUSH that undergoes a conformational shift upon cVA binding. The stable LUSH–cVA complex is the activating ligand for pheromone receptors present on the dendrites of the aT1 neurones, comprising the only neurones that detect cVA pheromone. This mechanism explains the single molecule sensitivity of insect pheromone detection systems. The receptor that recognizes activated LUSH consists of a complex of several proteins, including Or67d, a member of the tuning odourant receptor family, Orco, a co-receptor ion channel, and SNMP, a CD36 homologue that may be an inhibitory subunit. In addition, genetic screens and reconstitution experiments reveal additional factors that are important for pheromone detection. Identification and functional dissection of these factors in Drosophila melanogaster Meigen should permit the identification of homologous factors in pathogenic insects and agricultural pests, which, in turn, may be viable candidates for novel classes of compounds to control populations of target insect species without impacting beneficial species. PMID:24347807

  17. The physiological and ecological roles of volatile halogen production by marine diatoms

    NASA Astrophysics Data System (ADS)

    Hughes, Claire; Sun, Shuo

    2015-04-01

    Sea-to-air halogen flux is known to have a major impact on catalytic ozone cycling and aerosol formation in the troposphere. The biological production of volatile organic (e.g. bromoform, diiodomethane) and reactive inorganic halogens (e.g. molecular iodine) is believed to play an important role in mediating halogen emissions from the marine environment. Marine diatoms in particular are known to produce the organic and inorganic volatile halogens at high rates in pelagic waters and sea-ice systems. The climate-induced changes in diatom communities that have already been observed and are expected to occur throughout the world's oceans as warming progresses are likely to alter sea-to-air halogen flux. However, we currently have insufficient understanding of the physiological and ecological functions of volatile halogen production to develop modelling tools that can predict the nature and magnitude of the impact. The results of a series of laboratory studies aimed at establishing the physiological and ecological role of volatile halogen production in two marine polar diatoms (Thalassiosira antarctica and Porosira glacialis) will be described in this presentation. We will focus on our work investigating how the activity of the haloperoxidases, a group of enzymes known to be involved in halogenation reactions in marine organisms, is altered by environmental conditions. This will involve exploring the antioxidative defence role proposed for marine haloperoxidases by showing specifically how halogenating activity varies with photosynthetic rate and changes in the ambient light conditions in the two model marine diatoms. We will also present results from our experiments designed to investigate how volatile halogen production is impacted by and influences diatom-bacterial interactions. We will discuss how improved mechanistic understanding like this could pave the way for future volatile halogen-ecosystem model development.

  18. Volatile organic compounds and metal leaching from composite products made from fiberglass-resin portion of printed circuit board waste.

    PubMed

    Guo, Jie; Jiang, Ying; Hu, Xiaofang; Xu, Zhenming

    2012-01-17

    This study focused on the volatile organic compounds (VOCs) and metal leaching from three kinds of composite products made from fiberglass-resin portion (FRP) of crushed printed circuit board (PCB) waste, including phenolic molding compound (PMC), wood plastic composite (WPC), and nonmetallic plate (NMP). Released VOCs from the composite products were quantified by air sampling on adsorbent followed by thermal desorption and GC-MS analysis. The results showed that VOCs emitted from composite products originated from the added organic components during manufacturing process. Phenol in PMC panels came primarily from phenolic resin, and the airborne concentration of phenol emitted from PMC product was 59.4 ± 6.1 ?g/m(3), which was lower than odor threshold of 100% response for phenol (180 ?g/m(3)). VOCs from WPC product mainly originated from wood flour, e.g., benzaldehyde, octanal, and d-limonene were emitted in relatively low concentrations. For VOCs emitted from NMP product, the airborne concentration of styrene was the highest (633 ± 67 ?g/m(3)). Leaching characteristics of metal ions from composite products were tested using acetic acid buffer solution and sulphuric acid and nitric acid solution. Then the metal concentrations in the leachates were tested by ICP-AES. The results showed that only the concentration of Cu (average = 893 mg/L; limit = 100 mg/L) in the leachate solution of the FRP using acetic acid buffer solution exceeded the standard limit. However, concentrations of other metal ions (Pb, Cd, Cr, Ba, and Ni) were within the standard limit. All the results indicated that the FRP in composite products was not a major concern in terms of environmental assessment based upon VOCs tests and leaching characteristics. PMID:22142243

  19. Catalytic oxidation process cleans volatile organics from exhaust

    SciTech Connect

    Haggin, J.

    1994-06-27

    Unsteady-state catalytic oxidation is the basis of a technology now becoming available in the US for removing volatile organic compounds (VOCs) from industrial exhaust streams. The technology originated in Russia and is being developed for the US market by Monsanto Enviro-Chem Systems, St. Louis. At least 149 of the 189 pollutants identified by EPA are VOCs. EPA estimates that the initial cost to industry for equipment to remove the hazardous materials will be about $350 million. The expected annual maintenance bill to treat the major pollution sources is about $182 million. Catalytic oxidizers are applicable to most, but not all, VOC removal applications. The advantages in most cases are VOC removal efficiencies of at least 99%, half the energy requirement of other systems, low operating temperatures, stable operation with variable flow rates and VOC concentrations, and low capital and operating costs.

  20. Volatile organic compound (VOC) control in ethylene plants

    SciTech Connect

    Grover, R.; Gomaa, H.M. [M.W. Kellogg Co., Houston, TX (United States)

    1994-12-31

    Volatile Organic Compounds (VOC) are compounds of carbon that combine with nitrogen oxides and other airborne chemicals, in the presence of sunlight (photochemically), to form ozone, which is a primary component of smog. Some common VOC include: benzene, toluene, xylene, naphtha, ethylene oxide, methyl ethyl ketone, acetone, and 1,3-Butadiene. Pollution of the atmosphere by VOC has been a subject of major concern. Therefore, VOC emissions are attracting increasing concern from public and government agencies. Ethylene plants have many multiple sources of VOC emissions. These sources can be divided into point emission sources, both continuous and intermittent, and fugitive emission sources. This paper discusses VOC emissions and controls for ethylene plants. The impact of environmental regulations are discussed with respect to new and existing ethylene plants. Typical VOC emission rates are quantified. Commercially available and emerging control technologies are reviewed.

  1. Commodity Price Volatility and the Sources of Growth

    E-print Network

    Cavalcanti, Tiago V. de V.; Mohaddes, Kamiar; Raissi, Mehdi

    2011-01-26

    Commodity Price Volatility and the Sources of Growth Tiago V. de V. Cavalcanti, Kamiar Mohaddes and Mehdi Raissi 17 January 2011 CWPE 1112 Commodity Price Volatility and the Sources of Growth#3; Tiago V... growth e¤ects of CTOT volatility o¤set the positive impact of commodity booms. JEL Classi?cations: C23, F43, O13, O40. Keywords: Growth, resource curse, commodity prices, volatility. #3;We are grateful to Hashem Pesaran, seminar participants at the CSAE...

  2. Volatile Sulphur Compounds in UHT Milk

    Microsoft Academic Search

    Z. Al-Attabi; B. R. DArcy; H. C. Deeth

    2008-01-01

    Several volatile sulphur compounds have been detected in raw and processed milk. These are hydrogen sulphide, methanethiol, carbonyl sulphide, dimethyl sulphide, carbon disulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl sulphoxide, and dimethyl sulphone. Many of these increase in milk during heat processing and are associated with the cooked flavor of heat-treated milks, particularly UHT and sterilized milk. Several researchers have attempted

  3. Volatiles in the outer solar system

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.

    1991-01-01

    Telescopic data on asteroids, comets, planets, and planetary satellites are acquired and analyzed in the study of volatile ices and gases that occur on their surfaces and in their atmospheres. Infrared spectral studies of certain classes of asteroids for an analysis of their mineralogical and organic constituents are included.

  4. VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

    EPA Science Inventory

    The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

  5. Volatile biogenic halocarbons in the northwest Atlantic

    Microsoft Academic Search

    R. M. Moore; R. Tokarczyk

    1993-01-01

    A suite of naturally produced volatile halomethanes which are potential sources of gaseous halogens to the atmosphere have been measured in the water column of the NW Atlantic Ocean. Bromoform, chlorodibromomethane, dichlorobromomethane, dibromomethane, and methyl iodide all showed higher concentrations in coastal waters than in the pelagic zone. Such a distribution is consistent with known sources of these compounds in

  6. Regulation, Trading Volume and Stock Market Volatility

    Microsoft Academic Search

    J. Harold Mulherin

    1990-01-01

    [fre] Régulation, Trading Volume and Stock Market Volatility. . Il est souvent avancé que la spéculation est la source d'une volatilité excessive des cours boursiers. Les autorités sont alors confrontées à un dilemme : renforcer la réglementation (par exemple en accroissant les coûts de transactions) réduit l'activité des opérateurs, ce qui va dans le bon sens, mais réduit la liquidité,

  7. Volatilization of EPTC: Simulation and measurement

    Microsoft Academic Search

    J. M. Baker; W. C. Koskinen; R. H. Dowdy

    1996-01-01

    Many of the organic chemicals used in agricultural production are susceptible to loss from the soil surface to the atmosphere by volatilization. Adequate prediction of the impact of these chemicals on the environment thus requires consideration of both downward movement through the soil to groundwater and upward movement in the gas phase to the atmosphere. We developed a method to

  8. VOLATILE ORGANIC SAMPLING TRAIN - SOOT INTERFERENCE REPORT

    EPA Science Inventory

    The U.S. Environmental Protection Agency uses Method 0030, the Volatile Organic Sampling Train (VOST), as a tool in determining the destruction and removal efficiencies of industrial boilers co-firing hazardous waste. ecently, concerns have been expressed over possible measuremen...

  9. Relative Liquidity and Future Volatility Marcela Valenzuela

    E-print Network

    Fryzlewicz, Piotr

    a limit order book distribution and captures the level of consensus on a security's trading price. Higher of several alternative measures. Keywords: order-driven markets, limit order book distribution, volatility reversals (Porter (2008)). When the limit order book is thin, i.e., when the volume of orders available

  10. Gas chromatography of volatile organic compounds

    NASA Technical Reports Server (NTRS)

    Zlatkis, A.

    1973-01-01

    System has been used for problems such as analysis of volatile metabolities in human blood and urine, analysis of air pollutants, and in tobacco smoke chemistry. Since adsorbent is reusable after porper reconditioning, method is both convenient and economical. System could be used for large scale on-site sampling programs in which sample is shipped to central location for analysis.

  11. Storage Cabinet for Volatile Toxic Chemicals

    Microsoft Academic Search

    LOUIS DiBERARDINIS; MELVIN W. FIRST; JOHN PRICE; KENNETH MARTIN

    1983-01-01

    It is common practice to store toxic volatile chemicals in a laboratory fume hood. Although this provides safe storage, it becomes necessary to operate the hood continuously, resulting in a continuous loss of conditioned air from the building. Often, bottles containing highly toxic chemicals are few in number and small in size so that the storage volume required for this

  12. LARGE SCALE OZONE VOLATILIZATION OF RUTHENIUM

    Microsoft Academic Search

    R. C. Feber; L. W. Niedrach; E. L. Zebroski

    1950-01-01

    The volatilization of ruthenium with ozone has been tested on a 50-gal ; scale with inactive ruthenium. Decontamination factors of 23, 22, and 49 were ; obtained in three successive runs. With several equipment modifications to ; minimize reflux and improve gas distribution, it is believed that preliminary ; confirmation of the design basis adequate to justify tests with active

  13. Volatiles in interplanetary dust particles and aerogels

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Harmetz, C. P.

    1991-01-01

    Volatiles measured in 25 interplanetary dust particles (IDPs) are a mixture of both indigenous materials and contaminants associated with the collection and processing of the ODPs prior to analysis. Most IDPs have been collected in the stratosphere using a silicone oil/freon mixture (20:1 ratio) coated on collector plates. Studies have shown that silicone oil, freon and hexane residues remain with the ODPs, despite attempts to clean the IDPs. Analysis of the IDPs with the LMMS-technique produces spectra with a mixture of indigeneous and contaminants components. The contamination signal can be identified and removed; however, the contamination signal may obscure some of the indigeneous component's signal. Employing spectra stripping techniques, the indigenous volatile constituents associated with the IDPs can be identified. Volatiles are similar to those measured in CI or CM carbonaceous chondrites. Collection of IDPs in low-Earth orbit utilizing a Cosmic Dust Collection Facility attached to Space Station Freedom has been proposed. The low-density material aerogel has been proposed as a collection substrate for IDPs. Our studies have concentrated on identifying volatile contaminants that are associated with aerogel. We have found that solvents used for the preparation of aerogel remain in aerogel and methods must be developed for removing the entrapped solvents before aerogels can be used for an IDP collection substrate.

  14. Headspace Volatiles of Scutellaria Baicalensis Georgi Flowers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile constituents of Baikal skullcap (Scutellaria baicalensis Georgi) flowers were isolated by solid-phase microextraction (SPME) and analyzed by GC and GC/MS. A total of 64 constituents was identified (constituting 57.1 – 89.9% of the total area), 13 of which were tentatively identified. beta...

  15. Analytical aspects of volatile substance abuse (VSA).

    PubMed

    Gaulier, Jean-Michel; Tonnay, Véronique; Faict, Thierry; Sayer, Hervé; Marquet, Pierre; Lachâtre, Gérard

    2003-07-01

    Through a case report, the authors illustrate the volatile substance abuse (VSA) toxicological investigation difficulties mainly due to evaporation of the compounds from postmortem samples and to the lack of reference data for interpretation. A 17-year-old man, student in a chemistry institute, was found dead with a plastic bag placed over his head. Several chemical substances were found in his belongings. Autopsy findings included serious pulmonary lesions and hemorrhagic digestive ulcerations. A large screening of drugs and toxic compounds and selective analyses for several classes of drugs of abuse were carried out in the autopsy samples. In particular, a headspace (HS), -gas chromatography/-mass spectrometry (GC/MS) technique was used to screen for volatile substances and metabolites in the biological samples and for residues of volatile substances on the surface of the plastic bag and in the chemicals found on the scene. The main analytical finding was the presence of alkanes (heptane, methyl-2-pentane, methyl-3-hexane, methylcyclohexane) in the gastric content. The literature data, VSA practices, long time-delay between death and autopsy, preservation conditions of the biological samples before analysis, and in-lab experiments on evaporation of volatile substances were considered to interpret this result. The present fatality was attributed to VSA with a gasoline-based stain remover like "eau écarlate," associated with a hypoxic recreation practice using a plastic bag. PMID:12877311

  16. Emerging Control Technologies for Volatile Organic Compounds

    Microsoft Academic Search

    Geeta Rani Parmar; N. N. Rao

    2008-01-01

    Environmental problems associated with volatile organic compounds (VOCs) in the atmosphere have provided the driving force for sustained fundamental and applied research in the area of environmental remediation. Conventional methods currently used to treat VOCs include incineration, condensation, adsorption, and absorption. Incineration and condensation are cost-effective only for moderate to high VOC concentrations. Adsorption and absorption do not destroy VOCs

  17. Stochastic volatility with leverage: fast likelihood inference

    Microsoft Academic Search

    Yasuhiro Omori; Siddhartha Chib; Neil Shephard; Jouchi Nakajima

    2004-01-01

    Kim, Shephard and Chib (1998) provided a Bayesian analysis of stochastic volatility models based on a very fast and reliable Markov chain Monte Carlo (MCMC) algorithm. Their method ruled out the leverage effect, which limited its scope for applications. Despite this, their basic method has been extensively used in financial economics literature and more recently in macroeconometrics. In this paper

  18. Shaken and Stirred: Explaining Growth Volatility

    Microsoft Academic Search

    William Easterly; Roumeen Islam; Joseph E. Stiglitz

    2000-01-01

    Abstract: This paper attempts to set forth a framework for thinking about growth volatility which is general enough to incorporatethe important structural, institutional, and policy variations among countries which might account for differences in theirmacroeconomic performance. And it focuses particularly on the role of the financial sector. The paper is divided into 2sections. The first discusses the importance of short

  19. Ozone Production Potential of Volatile Organic Compounds

    Microsoft Academic Search

    T. Butler; M. G. Lawrence; J. Lelieveld

    2010-01-01

    Calculation of the ozone production potential of Volatile Organic Compounds (VOC) has traditionally been performed using so-called incremental reactivity techniques. Here were present a new approach to this problem using a photochemical box model with a tagged chemical mechanism. The results of our approach are consistent with previous work, but deliver much more detailed information about the VOC intermediate oxidation

  20. Proboscis extension reflex platform for volatiles and semi-volatiles detection

    SciTech Connect

    Wingo, Robert M. (Los Alamos, NM); McCabe, Kirsten J. (Los Alamos, NM); Haarmann, Timothy K. (Jemez Pueblo, NM)

    2010-11-30

    The present invention provides an apparatus for the detection of volatile and semi-volatile chemicals using the olfactory abilities of honey bees that are trained to respond to the presence of a specific chemical in a sample of gas with the proboscis extension reflex (PER). In particular, the geometry and arrangement of the parts of the apparatus are such that the amount of surface area in contact with the sample of gas prior to its introduction to the bees is minimized to improve the detection of particular volatile and semi-volatile that have a tendency to "stick" to contacting surfaces, especially certain chemicals associated with explosives and narcotics. According to another aspect of the present invention, a pre-concentrating means is incorporated with the device to effectively increase the concentration of "sticky" chemicals presented to the insects.

  1. The Influence of Topography on Volatile Transport

    NASA Astrophysics Data System (ADS)

    Stansberry, John A.; Grundy, Will; Young, Leslie

    2014-11-01

    Topography can exert important influences on volatile transport on bodies, such as Pluto and Triton, with global atmospheres supported by vapor pressure equilibrium with volatile frost on the surface. First, because local energy balance depends on the illumination angle, volatile frost will preferentially sublime from (condense on) areas tilted towards (away from) the Sun, as has been previously modelled at small spatial scales [e.g. 1]. Topographic features can also cause a completely different kind of vertical volatile transport resulting from the decrease in atmospheric pressure with altitude. On Pluto and Triton the sublimation flux from a topographic feature approximately one km high is comparable to the seasonal or inter-hemispheric sublimation flux (1 g/cm2^/year). To the extent that seasonal transport influences the distribution of volatile ices (and related characteristics such as albedo, emissivity, reflectance spectrum), topography-driven transport will exert a comparable influence around features a km or more above (or below) the global mean altitude of the frost deposits. This implies that in addition to there being a global "frost temperature" (defined by the temperature at which the frost vapor pressure equals the atmospheric pressure), there is a "frost altitude" (defined by the globally-averaged altitude of all the volatile frost). The sense of topography-driven volatile transport is to denude high areas. Consider two frost patches with equilibrium temperatures equal to the frost temperature, but at different altitudes. The high(low)-altitude patch is in contact with a lower(higher)-pressure atmosphere due to the e^(-z/H) dependence of atmospheric pressure. If the high(low)-altitude patch is above(below) the frost altitude, frost will sublime from (condense on) the high (low) frost patch, resulting in net downhill transport. We present models for the combined effects of illumination and altitude on frost transport rates for simple topographic features and discuss how these may influence the appearance of Pluto's surface as it will be seen by the New Horizons spacecraft in July 2015. [1] Yelle (1992) Science 255, 1553-1555.

  2. Distribution of aroma volatiles in a population of tangerine hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While orange juice volatile composition has been well studied, little is known about volatiles in tangerines. This study was undertaken to determine the most common compounds present in 45 tangerine hybrids, and to find relationships among these hybrids based on volatile content. Fruits were harve...

  3. Why Does Stock Market Volatility Change over Time?

    Microsoft Academic Search

    G William Schwert

    1989-01-01

    This paper analyzes the relation of stock volatility with real and nominal macroeconomic volatility, economic activity, financial leverage, and stock trading activity using monthly data from 1857 to 1987. An important fact, previously noted by Robert R. Officer (1973), is that stock return variability was unusually high during the 1929-39 Great Depression. While aggregate leverage is significantly correlated with volatility,

  4. European Currency Volatility After Economic and Monetary Union

    Microsoft Academic Search

    Richard Heaney; John Swieringa

    2003-01-01

    Corporate and institutional foreign exchange market participants are sensitive to the effects of volatility on their day-to-day trading activities and so an important question is whether the introduction of the euro had an impact on foreign exchange rate volatility. Rather than compare individual currencies with the Euro we compare the pre 1999 volatility of three synthetic euro exchange rate series

  5. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    E-print Network

    Herndon, S. C.

    A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the ...

  6. Host habitat assessment by a parasitoid using fungal volatiles

    PubMed Central

    Steiner, Sven; Erdmann, Daniel; Steidle, Johannes LM; Ruther, Joachim

    2007-01-01

    Background The preference – performance hypothesis predicts that oviposition preference of insects should correlate with host suitability for offspring development. Therefore, insect females have to be able to assess not only the quality of a given host but also the environmental conditions of the respective host habitat. Chemical cues are a major source of information used by insects for this purpose. Primary infestation of stored grain by stored product pests often favors the intense growth of mold. This can lead to distinct sites of extreme environmental conditions (hot-spots) with increased insect mortality. We studied the influence of mold on chemical orientation, host recognition, and fitness of Lariophagus distinguendus, a parasitoid of beetle larvae developing in stored grain. Results Volatiles of wheat infested by Aspergillus sydowii and A. versicolor repelled female parasitoids in an olfactometer. Foraging L. distinguendus females are known to be strongly attracted to the odor of larval host feces from the granary weevil Sitophilus granarius, which may adhere in remarkable amounts to the surface of the grains. Feces from moldy weevil cultures elicited neutral responses but parasitoids clearly avoided moldy feces when non-moldy feces were offered simultaneously. The common fungal volatile 1-octen-3-ol was the major component of the odor of larval feces from moldy weevil cultures and repelled female parasitoids at naturally occurring doses. In bioassays investigating host recognition behavior of L. distinguendus, females spent less time on grains containing hosts from moldy weevil cultures and showed less drumming and drilling behavior than on non-moldy controls. L. distinguendus had a clearly reduced fitness on hosts from moldy weevil cultures. Conclusion We conclude that L. distinguendus females use 1-octen-3-ol for host habitat assessment to avoid negative fitness consequences due to secondary mold infestation of host patches. The female response to fungal volatiles is innate, suggesting that host-associated fungi played a crucial role in the evolution of host finding strategies of L. distinguendus. Research on the role of host-associated microorganisms in the chemically mediated orientation of parasitoids is still at the beginning. We expect an increasing recognition of this issue in the future. PMID:17284315

  7. Oxidation and volatilization of a niobium alloy

    SciTech Connect

    Smolik, G.R.; McCarthy, K.A.

    1992-07-01

    This report presents the findings from a preliminary investigation into oxidation and volatilization characteristics of a niobium alloy. Niobium is a candidate alloy for use in plasma facing components (PFCS) in experimental fusion reactors like the Intemational Thermonuclear Experimental Reactor (ITER). An experimental alloy was tailored to simulate small changes in chemistry which could result from transmutations from irradiation. The alloy was exposed in air and steam between 800[degree]C and 1200[degree]C. Volatilized products and hydrogen were collected and measured. Post-test examinations were also performed on the samples to determine the amount of material loss during the exposures. The obtained measurements of volatilization flux (g/m[sup 2]-s), hydrogen generation rates (liters/m[sup 2]-s), and recession rates (mm/s) are data which can be used for safety analyses and material performance to predict consequences which may result from an accident involving the ingress of air or steam into the plasma chamber of fusion reactor. In our volatility tests, only molybdenum and niobium were found at release levels above the detection limit. Although molybdenum is present at only 0.12 wt%, the quantities of this element volatilized in air are nearly comparable to the quantities of niobium released. The niobium release in steam is only three to four times higher than that of molybdenum in steam. The hydrogen production of the niobium alloy is compared with other PFC materials that we have tested, specifically, beryllium, graphite, and a tunesten alloy. At high temperatures, the hydrogen production rate of the niobium alloy is among the lowest of these materials, significantly lower than beryllium. To understand what this means in an accident situation, modeling is necessary to predict temperatures, and therefore total hydrogen production. The INEL is currently doing this modeling.

  8. Aroma volatiles from two fruit varieties of jackfruit ( Artocarpus heterophyllus Lam.)

    Microsoft Academic Search

    José Guilherme S Maia; Eloisa Helena A Andrade; Maria das Graças B Zoghbi

    2004-01-01

    The aroma volatiles from two fruit varieties of jackfruit (Artocarpus heterophyllus) growing in the Amazon were obtained by simultaneous distillation-extraction and analysed by GC–MS. The major components identified in the aroma concentrate of “hard jackfruit” variety were isopentyl isovalerate (28.4%) and butyl isovalerate (25.6%). The aroma concentrate of “soft jackfruit” was dominated by isopentyl isovalerate (18.3%), butyl acetate (16.5%), ethyl

  9. Volatile components in scent gland secretions of garter snakes ( Thamnophis spp.)

    Microsoft Academic Search

    William F. Wood; Joshua M. Parker; Paul J. Weldon

    1995-01-01

    Previous analyses of the scent gland secretions of snakes have focused on the nonvolatile components. Gas chromatography-mass spectrometry of secretions from North American garter snakes (Thamnophis butleri, T. couchi, T. elegans, T. melanogaster, andT. sirtalis) indicated the following seven major volatile components: acetic, propanoic, 2-methylpropanoic, butanoic, and 3-methylbutanoic acids, trimethylamine, and 2-piperidone. Five or more of these compounds were observed

  10. Volatile Constituents of the Seed and Fruit Skin Oils of Catimbium latilabre (Ridl.) Holtt. from Vietnam

    Microsoft Academic Search

    Piet A. Leclercq; Nguyêñ Xuân D?ng; Trinh Dình Chính; Dô Dình Rãng

    1994-01-01

    The volatile constituents of the seed and fruit skin oils of Catimbium latilabre (Ridl.) Holtt. from Vietnam were analyzed by a combination of high resolution GC and GC\\/MS. More than 55 components were found to be present in the seed oil, of which the major ones were ?-caryophyllene (25.8%), camphor (11.2%), caryophyllene oxide (5.7%), carotol (5.6%), ?-elemene (5.0%), benzyl acetone

  11. Development of an 18 GHz superconducting electron cyclotron resonance ion source at RCNP.

    PubMed

    Yorita, Tetsuhiko; Hatanaka, Kichiji; Fukuda, Mitsuhiro; Kibayashi, Mitsuru; Morinobu, Shunpei; Okamura, Hiroyuki; Tamii, Atsushi

    2008-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source has recently been developed and installed in order to extend the variety and the intensity of ions at the RCNP coupled cyclotron facility. Production of several ions such as O, N, Ar, Kr, etc., is now under development and some of them have already been used for user experiments. For example, highly charged heavy ion beams like (86)Kr(21+,23+) and intense (16)O(5+,6+) and (15)N(6+) ion beams have been provided for experiments. The metal ion from volatile compounds method for boron ions has been developed as well. PMID:18315101

  12. The effect of different levels of forage and fish meal on the live performance and rumen volatile fatty acid concentation of heifers fed high molasses diets 

    E-print Network

    Estrada, Sergio

    1973-01-01

    THE EFFECT OF DIFFERENT LEVELS OF FORAGE AND FISH MEAL ON THE LIVE PERFORMANCE AND RUMEN VOLATILE FATTY ACID CONCEN- TRATION OF HEIFERS FED HIGH MOLASSES DIETS A Thesis by SERGIO ESTRADA Submitted to the Graduate College of Texas ASM... University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1973 Major Subject: Animal Science THE EFFECT OF DIFFERENT LEVELS OF FORAGE AND FISH MEAL ON IHE LIVE PERFORMANCE AND RUMEN VOLATILE FATTY ACID CONCEN...

  13. Non-Methane Biogenic Volatile Organic Compound Emissions from a Subarctic Peatland Under Enhanced UV-B Radiation

    Microsoft Academic Search

    Patrick Faubert; Päivi Tiiva; A. Rinnan; J. Rasanen; Jarmo K. Holopainen; Toini Holopainen; E. Kyro; Riikka Rinnan

    2010-01-01

    Boreal and subarctic peatlands have been extensively studied for their major role in the global carbon balance. However, study efforts have so far neglected the contribution of these ecosystems to the non-methane biogenic volatile organic compound (BVOC) emissions, which are important in the atmospheric chemistry and feedbacks on climate change. We aimed at estimating the BVOC emissions from a subarctic

  14. Natural emissions of non-methane volatile organic compounds, carbon monoxide, and oxides of nitrogen from North America

    Microsoft Academic Search

    Alex Guenther; Chris Geron; Tom Pierce; Brian Lamb; Peter Harley; Ray Fall

    2000-01-01

    The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile organic compounds (NMVOC), carbon monoxide (CO) and nitric oxide (NO), that determine tropospheric oxidant concentrations. Natural sources include soil microbes, vegetation, biomass burning, and lightning. These sources are

  15. The use of multiple-strain algal sensor chips for the detection and identification of volatile organic compounds

    Microsoft Academic Search

    Björn Podola; Eva C. M Nowack; Michael Melkonian

    2004-01-01

    Although biosensors detecting a great variety of toxicants have been developed during the last decades, the simultaneous detection and identification of several targets by one biosensor is not possible in the majority of the biosensor systems. In our study we proved the concept of the detection and identification of two different volatile toxic compounds with a non-selective biochip-based algal biosensor.

  16. Induced Release of a Plant-Defense Volatile ‘Deceptively’ Attracts Insect Vectors to Plants Infected with a Bacterial Pathogen

    Microsoft Academic Search

    Rajinder S. Mann; Jared G. Ali; Sara L. Hermann; Siddharth Tiwari; Kirsten S. Pelz-Stelinski; Hans T. Alborn; Lukasz L. Stelinski

    2012-01-01

    Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina

  17. SCREENING FOR VOLATILE ORGANIC FATTY ACIDS IN AGRICULTURAL AIR USING SOLID-PHASE MICROEXTRACTION AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile fatty acids (VFAs) are a major component of odorous gases associated with agricultural sources. Because of typically low VFA air concentrations, conventional air sampling methods including sorbent tubes and vacuum canisters are often not sensitive enough to detect them. Solid phase microe...

  18. Behavioral and electrophysiological responses of Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) to cotton (Gossypium hirsutum L.) and some cotton volatile chemicals 

    E-print Network

    Baehrecke, Eric Harald

    1988-01-01

    BEHAVIORAL AND ELECTROPHYSIOLOGICAL RESPONSES OF CAMPOLETIS SONORENSIS CAMERON (HYMENOPTERA: ICHNEUMONIDAE) TO COTTON (GOSSYPIUM HIRSUTUM L. ) AND SOME COTTON VOLATILE CHEMICALS A Thesis by ERIC HARALD BAEHRECKE Submitted to the Graduate... College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Entomology BEHAVIORAL AND ELECTROPHYSIOLOGICAL RESPONSES OF CAMPOLETIS SONORENSIS CAMERON (HYMENOPTERA...

  19. Detection of volatile organic compounds indicative of human presence in the air.

    PubMed

    Kwak, Jae; Geier, Brian A; Fan, Maomian; Gogate, Sanjay A; Rinehardt, Sage A; Watts, Brandy S; Grigsby, Claude C; Ott, Darrin K

    2015-07-01

    Volatile organic compounds were collected and analyzed from a variety of indoor and outdoor air samples to test whether human-derived compounds can be readily detected in the air and if they can be associated with human occupancy or presence. Compounds were captured with thermal desorption tubes and then analyzed by gas chromatography with mass spectrometry. Isoprene, a major volatile organic compound in exhaled breath, was shown to be the best indicator of human presence. Acetone, another major breath-borne compound, was higher in unoccupied or minimally occupied areas than in human-occupied areas, indicating that its majority may be derived from exogenous sources. The association of endogenous skin-derived compounds with human occupancy was not significant. In contrast, numerous compounds that are found in foods and consumer products were detected at elevated levels in the occupied areas. Our results revealed that isoprene and many exogenous volatile organic compounds consumed by humans are emitted at levels sufficient for detection in the air, which may be indicative of human presence. PMID:25944350

  20. Plume composition and volatile flux from Nyamulagira volcano

    NASA Astrophysics Data System (ADS)

    Calabrese, Sergio; Bobrowski, Nicole; Giuffrida, Giovanni Bruno; Scaglione, Sarah; Liotta, Marcello; Brusca, Lorenzo; D'Alessandro, Walter; Arellano, Santiago; Yalire, Matiew; Galle, Bo; Tedesco, Dario

    2015-04-01

    Nyamulagira, in the Virunga volcanic province (VVP), Democratic Republic of Congo, is one of the most active volcanoes in Africa. The volcano is located about 25 km north-northwest of Lake Kivu in the Western Branch of the East African Rift System (EARS). The activity is characterized by frequent eruptions (on average, one eruption every 2-4 years) which occur both from the summit crater and from the flanks (31 flank eruptions over the last 110 years). Due to the peculiar low viscosity of its lava and its location in the floor of the rift, Nyamulagira morphology is characterized by a wide lava field that covers over 1100 km2 and contains more than 100 flank cones. Indeed, Nyamulagira is a SiO2- undersaturated and alkali-rich basaltic shield volcano with a 3058 m high summit caldera with an extension of about 2 km in diameter. In November 2014 a field expedition was carried out at Nyamulagira volcano and we report here the first assessment of the plume composition and volatile flux from Nyamulagira volcano. Helicopter flights and field observations allowed us to recognize the presence of lava fountains inside an about 350-meter wide pit crater. The lava fountains originated from an extended area of about 20 to 40 m2, in the northeast sector of the central caldera. A second smaller source, close to the previous described one, was clearly visible with vigorous spattering activity. There was no evidence of a lave lake but the persistence of intense activity and the geometry of the bottom of the caldera might evolve in a new lava lake. Using a variety of in situ and remote sensing techniques, we determined the bulk plume concentrations of major volatiles, halogens and trace elements. We deployed a portable MultiGAS station at the rim of Nyamulagira crater, measuring (at 0.5 Hz for about 3 hours) the concentrations of major volcanogenic gas species in the plume (H2O, CO2, SO2, H2S). Simultaneously, scanning differential optical absorption spectroscopy instruments were applied inside the crater as well as downwind the volcano and active alkaline traps (Raschig-Tube and Drechsel bottle) were exposed. The alkaline solution traps acidic species (CO2, SO2, H2S, HCl, HF, HBr, HI) due to the acid-base reactions. Moreover, filter packs technique have also been used to collect both the volatile phase of the plume (sulphur and halogen species) and the particulate phase (major and trace metals) emitted from the volcano. These new results will add to our lacking knowledge of volcanic degassing in VVP, and will increase constraints on the abundances and origins of volatiles from the mantle source which feeds volcanism in the western branch of the EARS.

  1. Effects of ethanol and long-chain ethyl ester concentrations on volatile partitioning in a whisky model system.

    PubMed

    Boothroyd, Emily L; Linforth, Robert S T; Cook, David J

    2012-10-10

    Ethanolic atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was used to analyze the headspace concentrations of a test set of 14 whisky volatile compounds above a series of aqueous ethanolic solutions differing in alcohol content (5-40% ABV) and with regard to concentration of ethyl hexadecanoate (0-500 mg/L). The latter was selected to represent the long-chain ethyl esters found at various concentrations in new-make spirit. Headspace ion intensities were modeled against ethanol and ethyl hexadecanoate concentrations as factors. A separate model was prepared for each compound. Not surprisingly, ethanol content in the range of 5-40% ABV had a significant effect (P < 0.0001) on headspace volatile concentrations of all volatile compounds, whereas the ethyl hexadecanoate concentration had a selective effect of reducing headspace concentrations of the more hydrophobic compounds (log P > 2.5). This finding is discussed in terms of the "structuring" effects of ethyl hexadecanoate when present above critical micelle concentration, leading to the selective incorporation of hydrophobic volatile compounds into the interior of micelle-like structures. Data presented illustrate that dilution of whiskies to 23% ABV for "nosing" in the presence of long-chain ethyl esters is likely to change the balance of volatile compounds in the headspace and thus the perceived aroma character. PMID:22958228

  2. Volatility in financial markets: stochastic models and empirical results

    NASA Astrophysics Data System (ADS)

    Miccichè, Salvatore; Bonanno, Giovanni; Lillo, Fabrizio; Mantegna, Rosario N.

    2002-11-01

    We investigate the historical volatility of the 100 most capitalized stocks traded in US equity markets. An empirical probability density function (pdf) of volatility is obtained and compared with the theoretical predictions of a lognormal model and of the Hull and White model. The lognormal model well describes the pdf in the region of low values of volatility whereas the Hull and White model better approximates the empirical pdf for large values of volatility. Both models fail in describing the empirical pdf over a moderately large volatility range.

  3. Hydropower major rehabilitation projects

    SciTech Connect

    Norlin, J.A. [Army Corps of Engineers, Portland, OR (United States)

    1995-12-31

    The Corps of Engineers has developed an active Major Rehabilitation Program to handle large, long duration restoration projects. These projects are funded by specific appropriations and subsequently are required to have detailed rehabilitation plans to justify the work. The emphasis of the Major Rehabilitation Program is correcting reliability problems. Papers that were presented at Waterpower `93 discussed the basic concepts that are required in preparing a Major Rehabilitation Evaluation Report. This paper will cover the current status of each of the current major rehabilitation projects that the Corps of Engineers has in progress.

  4. Influence of thermal processing on the volatile constituents of muskmelon puree.

    PubMed

    Priyanka, D; Sindhoora, S; Vijayanand, P; Kulkarni, S G; Nagarajan, S

    2015-05-01

    Muskmelon (Cucumis melo L) is an important tropical fruit cultivated widely in different parts of India. Fresh muskmelon has a delicate but characteristic flavor rendering the fruit with highly acceptable flavor. Processing and preservation of muskmelon puree requires thermal processing, which affects the volatile constituents. It is imperative to understand the flavor changes during thermal processing which would affect the quality of the processed and packed muskmelon puree. Muskmelon puree was subjected to different methods of thermal processing viz., heating, canning and packing in retort pouches and the volatile constituents were analyzed. Gas chromatography-mass spectrometry (GC-MS) indicated the presence of more than 49 volatile components in the muskmelon puree samples. Major volatile components identified using GC-MS analysis showed the presence of esters (27.29 %), aldehydes (18.57 %), Heterocyclic compounds (16.63 %), aliphatic alcohols (11.72 %), phenolic compounds (6.03 %) and sesquiterpenes (0.25 %) in the fresh samples. Aldehydes decreased and ester content increased in thermally processed muskmelon puree packed in cans and retort pouches. Aliphatic alcohols, Heterocyclic compounds and phenolic compounds decreased in puree processed in tin containers and retort pouches. PMID:25892817

  5. Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?

    NASA Astrophysics Data System (ADS)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-02-01

    High concentration of volatile nucleation mode particles (NUP) formed in the atmosphere during exhaust cools and dilutes have hazardous health effects and impair visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulphur content (FSC), under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested; based on the measured gaseous sulphuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrierless heteromolecular homogeneous nucleation between GSA and semi-volatile organic vapour (for example adipic acid) combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur by the same organic vapour at concentrations of (1-2) ×1012cm-3. The pre-existing core and soot mode concentrations had opposite trend on the NUP formation, and maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, NUP formation was ceased if the GSA concentration was less than 1010cm-3 which suggests, based on the measurements, the usage of biofuel to prevent volatile particles in diesel exhaust.

  6. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    SciTech Connect

    Ouellette, B.A.

    1994-09-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which represent a cross section of the current inventory of USAF wastewater plants in ozone nonattainment areas. From these calculations, maximum facility emissions are determined which represent the upper limit for the potential VOC emissions from these wastewater plants. Based on the calculated emission estimates, each selected wastewater facility is evaluated as a potential major stationary source of volatile organic emissions under both Title I of the 1990 CAAA and the plant's governing Clean Air Act state implementation plan. Next, the potential impact of the specific volatile organics being emitted is discussed in terms of their relative reactivity and individual contribution to tropospheric ozone formation. Finally, a relative comparison is made between the estimated VOC emissions for the selected wastewater facilities and the total VOC emissions for their respective host installations.

  7. Rust and schreibersite in Apollo 16 highland rocks - Manifestations of volatile-element mobility

    NASA Technical Reports Server (NTRS)

    Hunter, R. H.; Taylor, L. A.

    1982-01-01

    Rust is a manifestation of halogen and volatile-metal mobility in the lunar environment. Schreibersite is stable as the primary phosphorus-bearing phase in the highland rocks, a consequence of the inherently low oxygen fugacity within impact-generated melts. Apatite and whitlockite are subordinate in these rocks. The partitioning of P into phosphide in impact-generated melts, and the failure of phosphate to crystallize, effects a decoupling of the halogens and phosphorus. Of the Apollo 16 rocks, 63% contain rust, 70% contain schreibersite, and 52% contain both phases, thereby establishing the pervasiveness of volatile-elements throughout the highland rocks. The major portion of these volatile-bearing phases occur in impact melt-rocks or in breccia matrices. Rhabdites of schreibersite in some of the FeNi grains indicate that there is a meteoritic contribution to the phosphorus in these rocks. Cl/P2O5 ratios in lunar highland rocks are a function of secondary effects, with any apparent Cl-P correlations being coincidential. The present observations preclude the validity of models based on such elemental ratios in these rocks. The presence of rust in the clast laden matrices of pristine rocks indicates fugitive element localization. Pristine clasts may have been contaminated. The basis for a pristine volatile chemistry is questioned.

  8. Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

    PubMed Central

    Weise, Teresa; Kai, Marco; Gummesson, Anja; Troeger, Armin; von Reuß, Stephan; Piepenborn, Silvia; Kosterka, Francine; Sklorz, Martin; Zimmermann, Ralf; Francke, Wittko

    2012-01-01

    Summary Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial–plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR–MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 ?mol), whereas decan-2-one at 100 ?mol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose. PMID:22563356

  9. Space exploration and the history of solar-system volatiles

    NASA Technical Reports Server (NTRS)

    Fanale, F. P.

    1976-01-01

    The thermochemical history of volatile substances in all solar-system planets, satellites, and planetoids is discussed extensively. The volatiles are viewed as an interface between the abiotic and biotic worlds and as a key to the history of bodies of the solar system. A flowsheet of processes and states is exhibited. Differences in bulk volatiles distribution between the planetary bodies and between the interior, surface, and atmosphere of each body are considered, as well as sinks for volatiles in degassing. The volatiles-rich Jovian and Saturnian satellites, the effect of large-planet magnetosphere sweeps on nearby satellites, volatiles of asteroids and comets, and the crucial importance of seismic, gravity, and libration data are treated. A research program encompassing analysis of the elemental and isotopic composition of rare gas in atmospheres, assay of volatiles-containing phases in regoliths, and examination of present or past atmospheric escape/accretion processes is recommended.

  10. Changes in the Major Volatile Compounds of Cider Distillates During Maturation

    Microsoft Academic Search

    Juan Mangas; Roberto Rodr??guez; Javier Moreno; Domingo Blanco

    1996-01-01

    Principal aroma components in cider distillates were determined by gas chromatography with direct sample injection; the method described was found to be reliable. Acetaldehyde decreased during aging, which could be a consequence of the interaction of this molecule with ethanol, since an increase of acetal level was detected. A higher concentration of methanol was observed in spirits obtained from cider

  11. The nitrogen source impacts major volatile compounds released by Saccharomyces cerevisiae during alcoholic fermentation.

    PubMed

    Barbosa, Catarina; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

    2012-11-15

    Sulphur-containing amino acids, cysteine and methionine, are generally found in very low concentrations in grape-juice. The objective of this study was to identify the effects of methionine on aroma compounds formation. Nitrogen source effects on growth, fermentative behaviour and aroma compounds formation were evaluated in three strains of Saccharomyces cerevisiae cultivated in batch under moderate nitrogen concentration, 267mg YAN/L, supplied as di-ammonium phosphate (DAP), a mixture of amino acids with (AA) or without methionine (AA(wMet)), and a mixture of AA plus DAP. Fermentative vigour and final biomass yields were dependent on the nitrogen source, for each of the strains tested, in particular for EC1118. Additionally, despite the strain-dependent behaviour with respect to the basal level of H(2)S produced, the comparison of treatments AA and AA(wMet) showed that presence of methionine suppressed H(2)S production in all strains tested, and altered aroma compound formation, particularly some of those associated with fruity and floral characters which were consistently more produced in AA(wMet). Moreover, DAP supplementation resulted in a remarkable increase in H(2)S formation, but no correlation between sulphide produced and yeast fermentative vigour was observed. Results suggest that the use of different nitrogen sources results in the production of wines with divergent aroma profiles, most notably when EC1118 strain is used. Methionine determination and its management prior to fermentation are crucial for suppressing H(2)S and to endowing beverages with diverse sensory traits. PMID:23177046

  12. Identification of major histocompatibility complex-regulated body odorants by statistical analysis of a comparative gas chromatography/mass spectrometry experiment.

    PubMed

    Willse, Alan; Belcher, Anne M; Preti, George; Wahl, Jon H; Thresher, Miranda; Yang, Peter; Yamazaki, Kunio; Beauchamp, Gary K

    2005-04-15

    This paper examines the application of gas chromatography/mass spectrometry (GC/MS) in a comparative experiment to identify volatile compounds from urine that differ in concentration between two groups of inbred mice. A complex mixture might comprise several hundred or even thousands of volatile compounds. Because their number and location in a chromatogram are generally unknown, and because components overlap in populous chromatograms, the statistical problems offer significant challenges beyond traditional two-group screening procedures. We describe a statistical procedure to compare two-dimensional GC/MS profiles between groups, which entails (1) signal processing, baseline correction, and peak detection in single ion chromatograms; (2) aligning chromatograms in time; (3) normalizing differences in overall signal intensities; and (4) detecting chromatographic regions that differ between groups. In an application to chemosignaling, we detect differences in GC/MS chromatograms of ether-extracted urine collected from two inbred groups of mice that differ only in genes of the major histocompatibility complex (MHC). Several dozen MHC-regulated compounds are found, including two known mouse pheromones, 2,5-dimethylpyrazine and 2-sec-butyl-4,5-dihydrothiazole. PMID:15828767

  13. MSI.R scripts reveal volatile and semi-volatile features in low-temperature plasma mass spectrometry imaging (LTP-MSI) of chilli (Capsicum annuum).

    PubMed

    Gamboa-Becerra, Roberto; Ramírez-Chávez, Enrique; Molina-Torres, Jorge; Winkler, Robert

    2015-07-01

    In cartography, the combination of colour and contour lines is used to express a three-dimensional landscape on a two-dimensional map. We transferred this concept to the analysis of mass spectrometry imaging (MSI) data and developed a collection of R scripts for the efficient evaluation of .imzML archives in a four-step strategy: (1) calculation of the density distribution of mass-to-charge ratio (m/z) signals in the .imzML file and assembling of a pseudo-master spectrum with peak list, (2) automated generation of mass images for a defined scan range and subsequent visual inspection, (3) visualisation of individual ion distributions and export of relevant .mzML spectra and (4) creation of overlay graphics of ion images and photographies. The use of a Hue-Chroma-Luminance (HCL) colour model in MSI graphics takes into account the human perception for colours and supports the correct evaluation of signal intensities. Further, readers with colour blindness are supported. Contour maps promote the visual recognition of patterns in MSI data, which is particularly useful for noisy data sets. We demonstrate the scalability of MSI.R scripts by running them on different systems: on a personal computer, on Amazon Web Services (AWS) instances and on an institutional cluster. By implementing a parallel computing strategy, the execution speed for .imzML data scanning with image generation could be improved by more than an order of magnitude. Applying our MSI.R scripts ( http://www.bioprocess.org/MSI.R ) to low-temperature plasma (LTP)-MSI data shows the localisation of volatile and semi-volatile compounds in the cross-cut of a chilli (Capsicum annuum) fruit. The subsequent identification of compounds by gas and liquid chromatography coupled to mass spectrometry (GC-MS, LC-MS) proves that LTP-MSI enables the direct measurement of volatile organic compound (VOC) distributions from biological tissues. PMID:26007697

  14. Do price and volatility jump together?

    E-print Network

    Jacod, Jean; 10.1214/09-AAP654

    2010-01-01

    We consider a process $X_t$, which is observed on a finite time interval $[0,T]$, at discrete times $0,\\Delta_n,2\\Delta_n,\\ldots.$ This process is an It\\^{o} semimartingale with stochastic volatility $\\sigma_t^2$. Assuming that $X$ has jumps on $[0,T]$, we derive tests to decide whether the volatility process has jumps occurring simultaneously with the jumps of $X_t$. There are two different families of tests for the two possible null hypotheses (common jumps or disjoint jumps). They have a prescribed asymptotic level as the mesh $\\Delta_n$ goes to $0$. We show on some simulations that these tests perform reasonably well even in the finite sample case, and we also put them in use on S&P 500 index data.

  15. Volatiles from rhizomes of Rhodiola rosea L.

    PubMed

    Rohloff, Jens

    2002-03-01

    Terpenes and aroma volatiles from rhizomes of Rhodiola rosea L. from Norway have been isolated by both steam distillation and headspace solid-phase micro-extraction coupled with gas chromatography and mass spectrometry analysis. The dried rhizomes contained 0.05% essential oil with the main chemical classes: monoterpene hydrocarbons (25.40%), monoterpene alcohols (23.61%) and straight chain aliphatic alcohols (37.54%). n-Decanol (30.38%), geraniol (12.49%) and 1,4-p-menthadien-7-ol (5.10%) were the most abundant volatiles detected in the essential oil, and a total of 86 compounds were identified in both the SD and HS-SPME samples. Geraniol was identified as the most important rose-like odour compound besides geranyl formate, geranyl acetate, benzyl alcohol and phenylethyl alcohol. Floral notes such as linalool and its oxides, nonanal, decanal, nerol and cinnamyl alcohol highlight the flowery scent of rose root rhizomes. PMID:11867098

  16. Characterisation of calamansi (Citrus microcarpa). Part II: volatiles, physicochemical properties and non-volatiles in the juice.

    PubMed

    Cheong, Mun Wai; Zhu, Danping; Sng, Jingting; Liu, Shao Quan; Zhou, Weibiao; Curran, Philip; Yu, Bin

    2012-09-15

    Calamansi juices from three countries (Malaysia, the Philippines and Vietnam) were characterised through measuring volatiles, physicochemical properties and non-volatiles (sugars, organic acids and phenolic acids). The volatile components of manually squeezed calamansi juices were extracted using dichloromethane and headspace solid-phase microextraction, and then analysed using gas chromatography-mass spectrometry/flame ionisation detector, respectively. A total of 60 volatile compounds were identified. The results indicated that the Vietnam calamansi juice contained the highest amount of volatiles. Two principal components obtained from principal component analysis (PCA) represented 89.65% of the cumulative total variations of the volatiles. Among the non-volatile components, these three calamansi juices could be, to some extent, differentiated according to fructose and glucose concentrations. Hence, this study of calamansi juices could lead to a better understanding of calamansi fruits. PMID:23107680

  17. Volatile liquid hydrocarbons in the marine environment

    Microsoft Academic Search

    1978-01-01

    Open ocean, nonpetroleum polluted surface water of the Gulf of Mexico contained volatile liquid hydrocarbons (VLH) concentrations of approx. 60 ng\\/l. while values in the heavily polluted Louisiana shelf and coast reached approx. 500 ng\\/l. Caribbean surface samples had concentrations of approx. 30 ng\\/l. An approximate linear relationship was found between anthropogenic gaseous hydrocarbons and VLH. Aromatic VLH accounted for

  18. Parasitic wasps orient to green leaf volatiles

    Microsoft Academic Search

    Douglas W. Whitman; Fred J. Eller

    1990-01-01

    Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in

  19. Volatiles from rhizomes of Rhodiola rosea L

    Microsoft Academic Search

    Jens Rohloff

    2002-01-01

    Terpenes and aroma volatiles from rhizomes of Rhodiola rosea L. from Norway have been isolated by both steam distillation and headspace solid-phase micro-extraction coupled with gas chromatography and mass spectrometry analysis. The dried rhizomes contained 0.05% essential oil with the main chemical classes: monoterpene hydrocarbons (25.40%), monoterpene alcohols (23.61%) and straight chain aliphatic alcohols (37.54%). n-Decanol (30.38%), geraniol (12.49%) and

  20. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se, especially in low phosphate regimes such as oligotrophic waters and late stage phytoplankton blooms.

  1. Day trading and stock price volatility

    Microsoft Academic Search

    Petri Kyröläinen

    2008-01-01

    When an investor buys and sells the same stock on the same day, he is said to have made a day trade. Using the trading records\\u000a of Finnish traders, this paper examines whether day trading is related to volatility of stock prices. I find a strong positive\\u000a time-series relation between the number of day trades by individual investors and intraday

  2. Volatile components in forest stands of Karelia

    SciTech Connect

    Fuksman, I.L. [Institute of Forestry, Karelia (Russian Federation)

    1995-09-01

    Study of the qualitative and quantitative composition of volatile organic compounds in forests stands of Karelia is made. A decrease in temperature and an increase in the relative air humidity adversely affect their emission. To study the relationship between the processes of the synthesis of essential oils in woody plants and the release of their components into the environment, a qualitative and quantitative determination of essential oils in pine branches was carried out. 13 refs., 3 figs., 4 tabs.

  3. Guaianolides and volatile compounds in chamomile tea.

    PubMed

    Tschiggerl, Christine; Bucar, Franz

    2012-06-01

    Chamomile (German Chamomile, Matricaria recutita L., Asteraceae) is one of the most popular medicinal plants in use as an herbal tea for food purposes and in folk medicine. Qualitative and semi-quantitative analyses of the volatile fraction of chamomile herbal tea were performed. Volatile constituents of the infusion were isolated by two different methods, namely hydrodistillation and solid phase extraction (SPE), and analysed by GC-MS. The relative proportions of particular chemical classes, present in the essential oil and volatile fractions of the infusion showed remarkable differences. The proportion of mono- and sesquiterpene hydrocarbons in the infusion, as compared to the essential oil, was significantly lower. Strikingly, the dichloromethane extract of the infusion contained a lower amount of bisabolol oxides and chamazulene, but higher amounts of spiroethers, sesquiterpene lactones and coumarins, as compared to the hydrodistillates of the herbal drug and the infusion. In addition to the previously known guaianolides matricarin and achillin, acetoxyachillin and leucodin (= desacetoxymatricarin), corresponding C-11 stereoisomers with various biological activities typically occurring in Achillea species, were identified in the dichloromethane extract of chamomile tea for the first time. PMID:22410959

  4. Volatile and sensory profiling of cocktail bitters.

    PubMed

    Johnson, Arielle J; Heymann, Hildegarde; Ebeler, Susan E

    2015-07-15

    Aromatic cocktail bitters are derived from the alcoholic extraction of a variety of plant materials and are used as additives in mixed drinks to enhance aroma and flavor. In this study sixteen commercial bitters were analyzed using volatile (GC-MS) and sensory profiling and multivariate statistics including Principal Component Analysis (PCA) and Partial Least Squares Regression (PLS). The samples differed significantly in their citrus, celery, and spice characteristics. 148 volatile compounds were tentatively identified and the composition varied significantly with the type of bitters sample evaluated. PLS analysis showed that the volatile data correlated well overall to the sensory data, explaining 60% of the overall variability in the dataset. Primary aldehydes and phenylpropanoids were most closely related to green and spice-related sensory descriptors. However, the sensory impact of terpenoid compounds was difficult to predict in many cases. This may be due to the wide range of aroma qualities associated with terpenes as well as to concentration, synergistic or masking effects. PMID:25722175

  5. Volatilization and efflux of mercury from biologically productive ocean regions

    SciTech Connect

    Kim, J.P.

    1987-01-01

    Mercury volatilization and oceanic evasion to the atmosphere were investigated in the tropical Pacific Ocean with emphasis on the biologically productive equatorial region. Further studies were conducted at two stations in the oligiotrophic North Pacific gyre, and in the estuarine mesocosms at the Marine Ecosystems Research Laboratory (MERL), University of Rhode Island. Dissolved gaseous Hg (DGM) in the tropical Pacific along 150/degree/ W at 4 stations ranged from 35-85 femtomoles per liter (fM) in surface waters and from 105-185 fM in deeper waters. Speciation experiments indicated that Hg/degree/was the dominant form in surface waters, while evidence for (CH/sub 3/)/sub 2/Hg was found at depth. In equatorial Pacific surface waters, DGM varied between 60 and 225 fM. Elemental Hg appears to comprise the major fraction of DGM. Elevated DGM concentrations corresponded with increased chlorophyll a levels and cooler, nutrient-rich waters. Surface waters of the equatorial Pacific were supersaturated with respect to Hg/degree/. Local Hg effluxes, estimated with a thin-film gas exchange model, were between 225 and 1050 pmoles/m/sup 2/ day. The annual Hg efflux from the equatorial Pacific, 1.6 /+-/ 1.3 /times/ 10/sup +6/ moles, was estimated at 4-5% of the total global Hg flux to the atmosphere. Dissolved gaseous Hg in the MERL mesocosms ranged from less than or equal to30 to 185 fM. In general, Hg/degree/ was the principal species, although (CH/sub 3/)/sub 2/minus// Hg was detected twice. Supersaturated levels of Hg/degrees/ corresponded with phytoplankton blooms of Cerataulina pelagica, Leptocylindrus danicus, Leptocylindrus mimimus, and Phaeocystis poucheti, suggesting that these phytoplankton could volatilize Hg in estuarine waters.

  6. Electron–Ion and Ion–Ion Dissociative Recombination of Oxygen. II. Ion–Ion Recombination

    Microsoft Academic Search

    F. T. Chan

    1968-01-01

    The rate coefficient and the thermal cross section for the oxygen ion–ion dissociative recombination are calculated using the semiclassical formalism. The motion of the heavy particles (positive and negative ions) in their mutual Coulomb field is treated classically. At certain ranges of the ion–ion separation (determined from energy conservation), the electron tunnels from the negative ion to the positive ion.

  7. Ion thruster performance model

    NASA Technical Reports Server (NTRS)

    Brophy, J. R.

    1984-01-01

    A model of ion thruster performance is developed for high flux density, cusped magnetic field thruster designs. This model is formulated in terms of the average energy required to produce an ion in the discharge chamber plasma and the fraction of these ions that are extracted to form the beam. The direct loss of high energy (primary) electrons from the plasma to the anode is shown to have a major effect on thruster performance. The model provides simple algebraic equations enabling one to calculate the beam ion energy cost, the average discharge chamber plasma ion energy cost, the primary electron density, the primary-to-Maxwellian electron density ratio and the Maxwellian electron temperature. Experiments indicate that the model correctly predicts the variation in plasma ion energy cost for changes in propellant gas (Ar, Kr and Xe), grid transparency to neutral atoms, beam extraction area, discharge voltage, and discharge chamber wall temperature. The model and experiments indicate that thruster performance may be described in terms of only four thruster configuration dependent parameters and two operating parameters. The model also suggests that improved performance should be exhibited by thruster designs which extract a large fraction of the ions produced in the discharge chamber, which have good primary electron and neutral atom containment and which operate at high propellant flow rates.

  8. Ion channels in microbes

    PubMed Central

    Martinac, Boris; Saimi, Yoshiro; Kung, Ching

    2008-01-01

    Summary Studies of ion channels have for long been dominated by the animalcentric, if not anthropocentric view of physiology. The structures and activities of ion channels had, however, evolved long before the appearance of complex multicellular organisms on Earth. The diversity of ion channels existing in cellular membranes of prokaryotes is a good example. Though at first it may appear as a paradox that most of what we know about the structure of eukaryotic ion channels is based on the structure of bacterial channels, this should not be surprising given the evolutionary relatedness of all living organisms and suitability of microbial cells for structural studies of biological macromolecules in a laboratory environment. Genome sequences of the human as well as various microbial, plant and animal organisms unambiguously established the evolutionary links, whereas crystallographic studies of the structures of major types of ion channels published over the last decade clearly demonstrated the advantage of using microbes as experimental organisms. The purpose of this review is not only to provide an account of acquired knowledge on microbial ion channels but also to show that the study of microbes and their ion channels may also hold a key to solving unresolved molecular mysteries in the future. PMID:18923187

  9. Herbivore-induced Blueberry Volatiles and Intra-plant Signaling

    PubMed Central

    Rodriguez-Saona, Cesar R.

    2011-01-01

    Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack1,2. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA)3,4,5. Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper6, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush7, poplar8, and lima beans9.. Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles5,6,10. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used n my study6 to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and analyzed. PMID:22214939

  10. Herbivore-induced blueberry volatiles and intra-plant signaling.

    PubMed

    Rodriguez-Saona, Cesar R

    2011-01-01

    Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA). Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush, poplar, and lima beans. Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used in my study to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and analyzed. PMID:22214939

  11. MECHANICAL ENGINEERING UNDERGRADUATE MAJOR

    E-print Network

    HANDBOOK FOR MECHANICAL ENGINEERING UNDERGRADUATE MAJOR Old Dominion University Department of Mechanical Engineering Batten College of Engineering and Technology Norfolk, Virginia 23529-0247 #12;TABLE OF CONTENTS MECHANICAL ENGINEERING HANDBOOK

  12. DCTD — Major Initiatives

    Cancer.gov

    Skip to Content Click here to view the Site Map Home | Sitemap | Contact DCTD Search this site Major Initiatives Search Grants Search Clinical Trials Ongoing Projects NCI Grants Policies Grant Application and Review Process DCTD Programs Cancer Diagnosis

  13. for Undergraduate CHEMISTRY MAJORS

    E-print Network

    Stuart, Steven J.

    and Petroleum Chemistry, Organic Chemistry, Physical Chemistry, Polymer Chemistry, Pulp and Paper Chemistry, RHANDBOOK for Undergraduate CHEMISTRY MAJORS DEPARTMENT OF CHEMISTRY Fall 2010 #12;#12;TABLE OF CONTENTS A Career in Chemistry - What It Means ___________________________________________ 4 What do

  14. An automated sampling system using ion mobility spectrometry for the rapid detection of bacteria

    Microsoft Academic Search

    N. J. C. Strachan; F. J. Nicholson; I. D. Ogden

    1995-01-01

    An ion mobility spectrometer coupled to an automated sampling system for rapid detection of bacteria is described. Examples are given of its applications to detect different species of bacteria of food safety concern. The method is based on the recognition of a volatile, metabolised enzymatically from a biochemical substrate, and detected by the ion mobility spectrometer.

  15. Tunable Networks from Thiolene Chemistry for Lithium Ion Catherine N. Walker,

    E-print Network

    Tew, Gregory N.

    ) by eliminating components such as the separator.3 Among commercially available batteries, lithium ion batteries to double the energy density and eliminate the volatile organic solvents, which pose a fire hazard.4Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction Catherine N. Walker, Craig

  16. Characterisation of volatiles in dried white varieties figs (Ficus carica L.).

    PubMed

    Muji?, Ibrahim; Bavcon Kralj, Mojca; Joki?, Stela; Jug, Tjaša; Subari?, Drago; Vidovi?, Senka; Zivkovi?, Jelena; Jarni, Kristjan

    2014-09-01

    The aromatic profile of volatiles in dried figs varieties Bružetka Bijela and Zimnica were characterised by headspace solid-phase (HS-SPME) procedure with gas chromatography-mass spectrometry analysis (GC-MS). The volatile compounds were distributed by distinct chemical classes, including alcohols, aldehydes, esters, terpenic compounds, and other compounds. The figs were dried in a pilot plant cabinet dryer. Prior to drying process, figs were pre-treated by sulphur dioxide, immersed in solution of citric acid and ascorbic acid, respectively. Several mathematical thin-layer drying models, available in the literature, were fitted to experimental data of figs, implementing non-linear regression analysis techniques. The results showed that pre-treatments of figs decrease significantly the drying time. The best thin-layer drying model in terms of fitting performance was Wang and Singh model. The major volatile compound in dried figs was benzaldehyde. After benzaldehyde, the most abundant aldehyde in dried figs was hexanal. The comparison among dried figs showed the highest abundance of aldehydes, in general, in non-treated (control) dried figs compared to pre-treated samples. Furthermore, ascorbic acid was the most efficient in preserving esters and alcohols in case of Bružetka Bijela, whereas in case of Zimnica, sulphur dioxide was in advance compared to ascorbic acid. Ethyl acetate was the most abundant ester found in dried figs. Among other compounds, 2-butanone,3-hydroxy was the most abundant identified volatiles. Linalool, as the only identified terpen, was in case of both dried fig varieties, preserved by immersion into ascorbic acid. The immersion into citric acid has not been so successful in volatiles conservation. PMID:25190838

  17. Delineating Effects of Ionic Strength and Suspended Solids on Ammonia Volatilization from Dairy Manure Slurry

    NASA Astrophysics Data System (ADS)

    Koirala, K.

    2014-12-01

    Ammonia emission is a major concern due to its adverse effects on animal and human health. Ionic strength and suspended solids play key roles in the ammonia volatilization process. These two parameters, however, are usually lumped together in form of total solids. The objective of this study was to separate the contribution of suspended solids (SS) from that of ionic strength (IS) on ammonia volatilization in liquid dairy manure. A two-way factorial experiment was conducted to simultaneously test the effects of IS and SS on ammonium dissociation: a key element of the ammonia volatilization process. The fraction of ammonia (?) in total ammoniacal nitrogen (TAN) was experimentally determined in a convective emission chamber, for each level of SS and IS, at a constant wind speed of 1.5 m s-1, and air and liquid temperature of 25°C. The two way analysis of variance showed a significant effect of SS concentration (p = 0.04) on fraction of ammonia in the liquid dairy manure, while the effect of ionic strength was marginal (p = 0.05). The highest dissociation of ammonium was observed in manure with the lowest SS concentration (0%) and the lowest ionic strength (0.10 mol L-1). Significant increases in suspended solids concentration and ionic strength were necessary to influence the ammonium dissociation in dairy manure. Results revealed that substantially high content of suspended solids (> 3.0%) or relatively high dilution of manure with water (30%) were necessary for these two parameters to play significant roles in the ammonia volatilization mechanism in liquid dairy manure. Results also showed that the ? was more sensitive to the changes in suspended solids concentration than in the changes in ionic strength within the ranges of SS and IS examined in this study. Overall, the SS and IS effects on ammonium dissociation (and by extension on ammonia volatilization process) were thus found negligible within the normal ranges of liquid dairy manure characteristics.

  18. Volatile production by buds and corollas of two sympatric, confamilial plants, Ipomopsis aggregata and Polemonium foliosissimum.

    PubMed

    Irwin, Rebecca E; Dorsett, Bob

    2002-03-01

    We used solid-phase microextraction of headspace samples followed by gas chromatography and mass spectrometry to identify and quantify the major volatile compounds produced by the buds and corollas of Ipomopsis aggregata (Polemoniaceae), and we compared them to a sympatric, confamilial plant species, Polemonium foliosissimum. The two species have distinct floral morphologies and pollinators, but share a common predispersal seed predator that oviposits under the calyces of buds. Ipomopsis aggregata buds emitted fewer compounds than the corollas. The buds of I. aggregata were dominated by alpha-pinene and, to a lesser extent, beta-pinene. The corollas of I. aggregata emitted a mixture of 10 compounds. Like the buds, I. aggregata corollas produced relatively high concentrations of alpha-pinene as well as caryophyllene. In addition, the emission of four terpenoids, three esters, and one ketone added to the volatile bouquet of the corollas. Polemonium foliosissimum buds also emitted fewer compounds than the corollas. The buds of P. foliosissimum were dominated by beta-pinene and, to a lesser extent, alpha-pinene. The corollas of P. foliosissimum were also dominated by beta-pinene along with three terpenoids, three alcohols, one ester, and two aldehydes. Comparing I. aggregata and P. foliosissimum, bud samples from both species produced considerable amounts of alpha- and beta-pinene. Ipomopsis aggregata emitted more alpha-pinene than beta-pinene, while P. foliosissimum emitted more beta-pinene. The corollas of the two species, however, differed in their volatile bouquet. The partition of volatiles between I. aggregata and P. foliosissimum buds and corollas and differences in volatile production between I. aggregata and P. foliosissimum are consistent with selection pressures exerted by organisms interacting with these plants. PMID:11944833

  19. Volatile organic compounds in selected micro-environments.

    PubMed

    Hinwood, A L; Berko, H N; Farrar, D; Galbally, I E; Weeks, I A

    2006-04-01

    A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds, 26 VOCs were detected in the samples collected. The highest concentrations were recorded for benzene, toluene, ethylbenzene, xylenes (BTEX), chloroform and styrene. The maximum 12-h toluene and benzene concentrations observed were from a basement carpark and were 24.7 parts per billion (ppb) and 5.6 ppb, respectively. The maximum xylenes concentration was 29.4 ppb and occurred in a nightclub where styrene was also detected. A factor analysis of the data was undertaken. Two key factors emerge that appear to be associated with petroleum and motor vehicles and environmental tobacco smoke. A third significant occurrence was a high concentration of chloroform that was observed at a sports centre complex with a swimming pool text and was uncorrelated with other compounds in the data set. This study indicates that locations associated with motor vehicles and petrol fuel, tobacco and wood smoke and chlorinated water represent the major risks for personal exposure to VOCs in Perth. PMID:16289288

  20. Alternately pulsed nanoelectrospray ionization/atmospheric pressure chemical ionization for ion/ion reactions in an electrodynamic ion trap.

    PubMed

    Liang, Xiaorong; Xia, Yu; McLuckey, Scott A

    2006-05-01

    The alternate operation of nanoelectrospray ionization and atmospheric pressure chemical ionization, using a common atmosphere/vacuum interface and ion path, has been implemented to facilitate ion/ion reaction experiments in a linear ion trap-based tandem mass spectrometer. The ion sources are operated in opposite polarity modes whereby one of the ion sources is used to form analyte ions while the other is used to form reagent ions of opposite polarity. This combination of ion sources is well-suited to implementation of experiments involving multiply charged ions in reaction with singly charged ions of opposite polarity. Three analytically useful ion/ion reaction types are illustrated: the partial deprotonation of a multiply protonated protein, the partial protonation of a multiply deprotonated oligonucleotide, and electron transfer to a multiply protonated peptide. The approach described herein is attractive in that it enables both single proton-transfer and single electron-transfer ion/ion reaction experiments to be implemented without requiring major modifications to the tandem mass spectrometer hardware. Furthermore, a wide range of reactant ions can be formed with these ionization methods and the pulsed nature of operation appears to lead to no significant compromise in the performance of either ion source. PMID:16643016

  1. Choosing a Major

    NSDL National Science Digital Library

    Joslyn Heiniger

    2009-09-27

    By completing this tutorial, you should be able to: Find resources to help you find the correct business major for you. Access your business major options. Congratulations on choosing Utah State University and the Jon M. Huntsman School of Business as your educational partner. Now that you have been admitted to USU, you may have a few questions about where to go from here. Below you will find many resources that will help you ...

  2. The Accounting Major

    NSDL National Science Digital Library

    Joslyn Heiniger

    2009-12-04

    By completing this tutorial, you should be able to: Find resources to aid in your research of the Accounting Major. Identify key aspects of an accounting career. Congratulations on choosing Utah State University and the Jon M. Huntsman School of Business as your educational partner. Now that you have been admitted to USU and selected accounting as your Huntsman major, you may have a few questions about where to go from here. Below you will ...

  3. Volatile fractions of landfill leachates and their effect on Chlamydomonas reinhardtii: In vivo chlorophyll a fluorescence

    SciTech Connect

    Brack, W.; Rottler, H.; Frank, H. [Univ. of Bayreuth (Germany)

    1998-10-01

    Volatile organic compounds such as short-chain halogenated hydrocarbons and alkylated benzenes are widely used as solvents or as intermediates in the chemical industry, and some of them are fuel components. Dichloromethane, trichloroethene, 1,1,1-trichloroethane, and tetrachloroethene have been produced in amounts of 500,000 to 1 million t/year, 80 to 100% of which are released to the environment. The production of toluene, a major component of fuels for internal combustion engines, amounts to about 30 million t/year. A method for identification of toxic volatile constituents of landfill leachates is presented that combines bioassay-compatible sample preparation, chemical analysis, and a bioassay based on in vivo chlorophyll a fluorescence of the green alga Chlamydomonas reinhardtii. Two major pathways of toxicity were identified by comparing fluorescence patterns: specific toxicity of hydrogen sulfide, and narcotic action of nonreactive organic compounds. For quantification, the contributions of identified compounds were calculated using toxic units. The ecotoxicologic relevance of volatile fractions from hazardous waste leachates was shown.

  4. A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.

    PubMed

    Allaire, S E; Yates, S R; Ernst, F F; Gan, J

    2002-01-01

    There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models. PMID:12175024

  5. Volatility dependence of Henry's law constants of condensable organics: Application to estimate depositional loss of secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Hodzic, A.; Aumont, B.; Knote, C.; Lee-Taylor, J.; Madronich, S.; Tyndall, G.

    2014-07-01

    The water solubility of oxidation intermediates of volatile organic compounds that can condense to form secondary organic aerosol (SOA) is largely unconstrained in current chemistry-climate models. We apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere to calculate Henry's law constants for these intermediate species. Results show a strong negative correlation between Henry's law constants and saturation vapor pressures. Details depend on precursor species, extent of photochemical processing, and NOx levels. Henry's law constants as a function of volatility are made available over a wide range of vapor pressures for use in 3-D models. In an application using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) over the U.S. in summer, we find that dry (and wet) deposition of condensable organic vapors leads to major reductions in SOA, decreasing surface concentrations by ~50% (10%) for biogenic and ~40% (6%) for short chain anthropogenic precursors under the considered volatility conditions.

  6. Metallic ions in the equatorial ionosphere

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Goldberg, R. A.

    1972-01-01

    Four positive ion composition measurements of the equatorial E region made at Thumba, India, are presented. During the day, the major ions between 90 and 125 km are NO(+) and O2(+). A metallic ion layer centered at 92 km is observed, and found to contain Mg(+), Fe(+), Ca(+), K(+), Al(+), and Na(+) ions. The layer is explained in terms of a similarly shaped latitude distribution of neutral atoms which are photoionized and charge-exchanged with NO(+) and O2(+). Three body reactions form molecular metallic ions which are rapidly lost by dissociative ion-electron recombination. Nighttime observations show downward drifting of the metallic ion layer caused by equatorial dynamo effects. These ions react and form neutral metals which exchange charges with NO(+) and O2(+) to produce an observed depletion of those ions within the metallic ion region.

  7. Determination of volatile compounds by GC-IMS to assign the quality of virgin olive oil.

    PubMed

    Garrido-Delgado, Rocío; Dobao-Prieto, María Del Mar; Arce, Lourdes; Valcárcel, Miguel

    2015-11-15

    The characterisation of different olive oil categories (extra virgin, virgin and lampante) using Ion Mobility Spectrometry (IMS) was improved by replacing the multicapillary column (MCC) with a capillary column (CC). The data obtained with MCC-IMS and CC-IMS were evaluated, studying both the global and the specific information obtained after the analysis of the volatile fraction of olive oils. A better differentiation of the oil categories was obtained employing CC vs MCC, since the classification percentage obtained with the CC-IMS was 92% as opposed to 87% obtained with MCC-IMS; although in productivity analytical terms, MCC offer a faster analysis than GC. The specific information obtained was also used to build a database, with a view to facilitating the characterization of specific attributes of olive oils. A total of 26 volatile metabolites (aldehydes, ketones, alcohols and esters) were identified. Finally, as revealed by an ANOVA test, some volatiles differed markedly in content among the different categories of oil. The data obtained confirms the potential of IMS as a reliable analytical screening technique, which can be used to assign the correct category to an olive oil sample. PMID:25977065

  8. Volatile organic carbon/air separation test using gas membranes

    SciTech Connect

    King, C.V.; Kaschemekat, J.

    1993-08-01

    An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed.

  9. [Analysis of residual volatiles in recycled polyethylene terephthalate].

    PubMed

    Ohkado, Yuka; Kawamura, Yoko; Mutsuga, Motoh; Tamura, Hiro-omi; Tanamoto, Kenichi

    2005-02-01

    The residual volatiles in recycled polyethylene terephthalate (PET) were analyzed using headspace/GC/MS. Recycled PET samples were made from PET bottles used for beverages, alcohol and soy sauce, and they were recycled in physical recycling plants, chemical recycling plants and superclean-like recycling trials. The physically recycled PET flakes contained small amounts of volatiles such as ethanol, limonene, 2-methyl-1,3-dioxolane, acetone, octanal and nonanal. Most of them originated from foods packed in bottles, and only 2-methyl-1,3-dioxolane was derived from polymer impurities. In contrast, the superclean-like or chemically recycled PET contained no detectable volatiles, like new PET pellets. The PET sheets shaped from physically recycled PET had no detectable volatiles. Not only the chemically and superclean-like recycled PET, but also the physically recycled PET contained no hazardous volatiles. It was concluded that there is no safety concern about volatiles in recycled PET, for the present use. PMID:15881250

  10. ION EXCHANGE

    EPA Science Inventory

    The IONEX program's name is a contraction of "ion exchange." The IONEX program performs calculations related to removing radium and/or uranium from water with the ion exchange process. IONEX provides a quick method of calculating whether a proposed ion exchange process will m...

  11. Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

    SciTech Connect

    Fehsenfeld, F.; Trainer, M. (National Oceanic and Atmospheric Administration, Boulder, CO (United States) Univ. of Colorado, Boulder (United States)); Calvert, J.; Guenther, A.B.; Zimmerman, P. (National Center for Atmospheric Research, Boulder, CO (United States)); Fall, R. (Univ. of Colorado, Boulder (United States)); Goldan, P.; Liu, S. (National Oceanic and Atmospheric Administration, Boulder, CO (United States)); Hewitt, C.N. (Lancaster Univ. (United Kingdom)); Lamb, B.; Westberg, H. (Washington State Univ., Pullman (United States))

    1992-12-01

    Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr[sup -1]. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed. 197 refs., 25 figs., 7 tabs.

  12. Identification of apple volatiles attractive to the apple maggot,Rhagoletis pomonella.

    PubMed

    Fein, B L; Reissig, W H; Roelofs, W L

    1982-12-01

    Apple volatiles from whole Red Delicious and Red Astrachan apples were found to be attractive to sexually mature apple maggot flies,Rhagoletis pomonella (Walsh), in wind tunnel bioassays. Extracted volatiles elicited directed upwind movement towards the source and significantly increased the number of male and female flies arriving at the source. A behaviorally active fraction was obtained from crude extract by gas-liquid chromatography and assayed in two types of wind tunnels and by electroantennography. The major components in this fraction, identified by chemical derivatization reactions and GLC-mass spectrometry, were hexyl acetate, (E)-2-hexen-1-yl acetate, butyl 2-methylbutanoate, propyl hexanoate, hexyl propanoate, butyl hexanoate, and hexyl butanoate in a 35?2 8?12?5?28?10 ratio. Synthetics of the identified compounds and the natural extract elicited similar behavioral and EAG responses. None of the synthetics or natural components elicited full activity when presented alone. PMID:24414891

  13. Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Fehsenfeld, Fred; Calvert, Jack; Fall, Ray; Goldan, Paul; Guenther, Alex B.; Hewitt, C. Nicholas; Lamb, Brian; Liu, Shaw; Trainer, Michael; Westberg, Hal; Zimmerman, Pat

    1992-12-01

    Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr-1. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed.

  14. Analysis of volatile components of cape gooseberry (Physalis peruviana L.) grown in Turkey by HS-SPME and GC-MS.

    PubMed

    Yilmaztekin, Murat

    2014-01-01

    Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts. PMID:24741358

  15. Analysis of Volatile Components of Cape Gooseberry (Physalis peruviana L.) Grown in Turkey by HS-SPME and GC-MS

    PubMed Central

    2014-01-01

    Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts. PMID:24741358

  16. Acid Gas Emissions Measured by COSPEC, Volatile Trap, and Filter Pack at Volcán Villarrica, South Chile

    NASA Astrophysics Data System (ADS)

    Witter, J. B.; Kress, V. C.; Delmelle, P.; Hersum, T. G.

    2001-12-01

    Volcán Villarrica is a basaltic andesite stratovolcano 170 km SE of Temuco, Chile. Villarrica has been characterized by continuous degassing from a summit lava lake since 1985. We present new measurements of the flux of SO2, HCl, and HF from Villarrica using correlation spectrometry (COSPEC) combined with the method of volatile traps and filter packs. COSPEC measurements yielded an average SO2 flux of 460+/-260 tons/day SO2. This is greater than, but within error of, the 260+/-170 tons/day SO2 measured by us last year. We assume H2S emission is negligible. Volatile trap and filter pack measurements were made at the summit crater. To test for diffuse degassing on the flanks of the volcano, we conducted a soil CO2 flux survey. Using an accumulation chamber configured with a continuous infrared CO2 gas analyzer, we found diffuse degassing of CO2 to be undetectable. We assume flank degassing of other gases is similarly low. Four volatile traps (6N KOH solution in a plastic beaker) were deployed at the active crater on three occasions for periods ranging from 8 to 13 days. Acid gas species were absorbed into the alkaline solution and the relative concentrations of SO4, Cl, and F were obtained by ion chromatography. Volatile traps yielded an average SO2/HCl ratio of 5.9+/-1.2 and HCl/HF ratio of 4.1+/-0.7. This compares with an average SO2/HCl ratio of 9.3+/-2.6 and HCl/HF ratio of 3.0+/-0.4 obtained with volatile traps in the 2000 field season. Twenty-three gas measurements were made using filter packs during eight summit days. Using a small vacuum pump we filtered the gas through a series of three paper filters each impregnated with a saturated sodium bicarbonate solution. Total filtration time varied from 3 to 46.5 minutes. Filtration time was chosen so that nearly all of the acid gases were absorbed by the first two filters in the filter stack. Relative concentrations of the acid gas species (SO4, Cl, and F) absorbed onto the filter paper were obtained by ion chromatography. Measurements of the acid gas species with filter packs yielded an average SO2/HCl ratio of 4.5+/-0.7 and HCl/HF ratio of 7.8+/-1.6. The volatile trap method is based on the assumption that the proportions of acid species absorbed into the alkaline solution are the same as those in the volcanic gas. Simultaneous collection of gas data using volatile traps and filter packs allows for a comparison of the two methods and an evaluation of this assumption. Filter packs yielded lower average SO2/HCl ratios but higher average HCl/HF and SO2/HF ratios. These results imply that the KOH solution in the volatile traps may not absorb S-gases and Cl as readily as it does F. Using gas ratios from filter pack measurements, we calculate average HCl and HF fluxes from Villarrica's summit crater of 102+/-42 tons/day and 13+/-3 tons/day, respectively. These values may be higher if H2S emission is significant.

  17. Exchange rates and oil prices: A multivariate stochastic volatility analysis

    Microsoft Academic Search

    Liang Ding; Minh Vo

    2012-01-01

    ► This paper models the volatilities of exchange rates and oil using MSV and MGARCH models. ► Both oil and FX markets respond to shocks simultaneously in normal time. ► There is bi-directional volatility interaction between markets inturbulent time. ► MSV models outperform others in fitting the data and forecasting exchange rate volatility. ► MGARCH models do better job in

  18. A jump diffusion model for VIX volatility options and futures

    Microsoft Academic Search

    Dimitris Psychoyios; George Dotsis; Raphael N. Markellos

    2010-01-01

    Volatility indices are becoming increasingly popular as a measure of market uncertainty and as a new asset class for developing\\u000a derivative instruments. Although jumps are widely considered as a salient feature of volatility, their implications for pricing\\u000a volatility options and futures are not yet fully understood. This paper provides evidence indicating that the time series\\u000a behaviour of the VIX index

  19. Volatile Memory Computer Forensics to Detect Kernel Level Compromise

    Microsoft Academic Search

    Sandra Ring; Eric Cole

    2004-01-01

    \\u000a This research presents a software-based computer forensics method capable of recovering and storing digital evidence from\\u000a volatile memory without corrupting the hard drive. Acquisition of volatile memory is difficult because it must be transferred\\u000a onto non-volatile memory prior to disrupting power. If this data is transferred onto the hard drive of the compromised computer\\u000a it could destroy critical evidence. This

  20. Contract Major Report Form Name __________________________

    E-print Network

    Kostic, Milivoje M.

    Contract Major Report Form 12/1/94 Name __________________________ Degree __________________________ College __________________________ Descriptive title of contract major _______________________________________________ Current GAP is ___________ in ___________________ hours attempted. Summary of Proposed contract Major 1

  1. Maximum likelihood approach for several stochastic volatility models

    NASA Astrophysics Data System (ADS)

    Camprodon, Jordi; Perelló, Josep

    2012-08-01

    Volatility measures the amplitude of price fluctuations. Despite it being one of the most important quantities in finance, volatility is not directly observable. Here we apply a maximum likelihood method which assumes that price and volatility follow a two-dimensional diffusion process where volatility is the stochastic diffusion coefficient of the log-price dynamics. We apply this method to the simplest versions of the expOU, the OU and the Heston stochastic volatility models and we study their performance in terms of the log-price probability, the volatility probability, and its Mean First-Passage Time. The approach has some predictive power on the future returns amplitude by only knowing the current volatility. The assumed models do not consider long-range volatility autocorrelation and the asymmetric return-volatility cross-correlation but the method still yields very naturally these two important stylized facts. We apply the method to different market indices and with a good performance in all cases.

  2. Ion Generators

    NASA Technical Reports Server (NTRS)

    1991-01-01

    "Kaufman thrusters," or electron bombardment thrusters, were developed for a spacecraft electric propulsion technique called ion propulsion. The technique, conceived by a Lewis Research Center engineer, is used by industry to etch microcircuits for electronic systems and deposition of thin films as coatings on gas atoms to create ions in a discharge chamber. The ions are ejected from the chamber as ion beams, then mixed with an equal number of electrons becoming a thrusting force. Commonwealth Scientific Corporation's product line derives largely from Dr. Kaufman's technology and includes ion sources for a number of applications.

  3. Rift initiation with volatiles and magma

    NASA Astrophysics Data System (ADS)

    Ebinger, Cynthia; Muirhead, James; Roecker, Steve; Tiberi, Christel; Muzuka, Alfred; Ferdinand, Rrichard; Mulibo, Gabrile; Kianji, Gladys

    2015-04-01

    Rift initiation in cratonic lithosphere remains an outstanding problem in continental tectonics, but strain and magmatism patterns in youthful sectors of the East African rift provide new insights. Few teleseisms occur in the Eastern rift arm of the East African rift system, except the southernmost sector in northern Tanzania where extension occurs in Archaean lithosphere. The change in seismic energy release occurs over a narrow along-axis zone, and between sectors with and without volcanoes in the central rift valley. Are these differences in strain behavior indicative of along-strike variations in a) rheology; b) strain transfer from border faults to magma intrusion zones; c) dike vs fault slip; and/or d) shallow vs deep magma chambers? We present time-space relations of seismicity recorded on a 38-station array spanning the Kenya-Tanzania border, focal mechanisms for the largest events during those time periods, and compare these to longer-term strain patterns. Lower crustal seismicity occurs along the rift length, including sectors on and off craton, and those with and without central rift valley volcanoes, and we see no clear along-strike variation in seismogenic layer thickness. One explanation for widespread lower crustal seismicity is high gas pressures and volatile migration from active metasomatism of upper mantle and magma degassing, consistent with very high volatile flux along fault zones, and widespread metasomatism of xenoliths. Volatile release and migration may be critical to strength reduction of initially cold, strong cratonic lithosphere. Seismicity patterns indicate strain (and fluid?) transfer from the Manyara border fault to Gelai shield volcano (faulting, diking) via Oldoinyo Lengai volcano. Our focal mechanisms and Global CMTs from an intense fault-dike episode (2007) show a local, temporally stable, rotation from ~E-W extension to NE-SE extension in this linkage zone, consistent with longer term patterns recorded in vent and eruptive chain alignments.

  4. A note on the pricing and hedging of volatility derivatives1

    Microsoft Academic Search

    S. D. HOWISON; A. RAFAILIDIS; H. O. RASMUSSEN

    2000-01-01

    We consider the pricing of volatility products and especially volatility and variance swaps. Under risk-neutral valuation we provide closed form formulae for volatility-average and variance swaps. Also we provide a general partial dierential equation for derivatives that have an extra dependence on an av- erage of the volatility. We give approximate solutions of this equation for volatility products written on

  5. Does futures trading increase stock market volatility? The case of the Nikkei stock index futures markets

    Microsoft Academic Search

    Eric C. Chang; Joseph W. Cheng; J. Michael Pinegar

    1999-01-01

    We propose new tests to examine whether stock index futures affect stock market volatility. These tests decompose spot portfolio volatility into the cross-sectional dispersion and the average volatility of returns on the portfolio's constituent securities. Our tests show that for Nikkei stocks spot portfolio volatility increased and cross-sectional dispersion decreased compared with average volatility when Nikkei futures began trading on

  6. Study of 'Redhaven' peach and its white-fleshed mutant suggests a key role of CCD4 carotenoid dioxygenase in carotenoid and norisoprenoid volatile metabolism

    PubMed Central

    2011-01-01

    Background Carotenoids are plant metabolites which are not only essential in photosynthesis but also important quality factors in determining the pigmentation and aroma of flowers and fruits. To investigate the regulation of carotenoid metabolism, as related to norisoprenoids and other volatile compounds in peach (Prunus persica L. Batsch.), and the role of carotenoid dioxygenases in determining differences in flesh color phenotype and volatile composition, the expression patterns of relevant carotenoid genes and metabolites were studied during fruit development along with volatile compound content. Two contrasted cultivars, the yellow-fleshed 'Redhaven' (RH) and its white-fleshed mutant 'Redhaven Bianca' (RHB) were examined. Results The two genotypes displayed marked differences in the accumulation of carotenoid pigments in mesocarp tissues. Lower carotenoid levels and higher levels of norisoprenoid volatiles were observed in RHB, which might be explained by differential activity of carotenoid cleavage dioxygenase (CCD) enzymes. In fact, the ccd4 transcript levels were dramatically higher at late ripening stages in RHB with respect to RH. The two genotypes also showed differences in the expression patterns of several carotenoid and isoprenoid transcripts, compatible with a feed-back regulation of these transcripts. Abamine SG - an inhibitor of CCD enzymes - decreased the levels of both isoprenoid and non-isoprenoid volatiles in RHB fruits, indicating a complex regulation of volatile production. Conclusions Differential expression of ccd4 is likely to be the major determinant in the accumulation of carotenoids and carotenoid-derived volatiles in peach fruit flesh. More in general, dioxygenases appear to be key factors controlling volatile composition in peach fruit, since abamine SG-treated 'Redhaven Bianca' fruits had strongly reduced levels of norisoprenoids and other volatile classes. Comparative functional studies of peach carotenoid cleavage enzymes are required to fully elucidate their role in peach fruit pigmentation and aroma. PMID:21269483

  7. Preparing for major incidents.

    PubMed

    De Winne, Joan

    2006-05-15

    Major incidents occurred, occur and will still occur all over the world, at any place at any time. Such an event is not always handled like it should and could be. The reason for this is not necessarily a deficiency in preplanning or the non-existence of procedures or guidelines. A possible solution to make things work more fluidly could be the creation of a genuine vision and mission statement on disaster handling followed by the alignment of all involved services within the statement. This would be a real challenge for all authorities and services involved in the planning phase and the preparation for major incidents. PMID:16542807

  8. Headspace analysis of volatile organic compounds from ethanolic systems by direct APCI-MS

    NASA Astrophysics Data System (ADS)

    Aznar, Margarita; Tsachaki, Maroussa; Linforth, Robert S. T.; Ferreira, Vicente; Taylor, Andrew J.

    2004-12-01

    Measuring the dynamic release of aroma compounds from ethanolic solutions by direct gas phase mass spectrometry (MS) techniques is an important technique for flavor chemists but presents technical difficulties as the changing ethanol concentration in the source makes quantitative measurements impossible. The effect of adding ethanol into the source via the sweep gas (0-565 [mu]L ethanol/L N2), to act as the proton transfer reagent ion and thereby control ionization was studied. With increasing concentrations of ethanol in the source, the water ions were replaced by ethanol ions above 3.2 [mu]L/L. The effect of source ethanol on the ionization of eleven aroma compounds was then measured. Some compounds showed reduced signal (10-40%), others increased signal (150-400%) when ionized via ethanol reagent ions compared to water reagent ions. Noise also increased in most cases so there was no overall increase in sensitivity. Providing the ethanol concentration in the source was >6.5 [mu]L/L N2 and maintained at a fixed value, ionization was consistent and quantitative. The technique was successfully applied to measure the partition of the test volatile compounds from aqueous and 12% ethanol solutions at equilibrium. Ethanolic solutions decreased the partition coefficient of most of the aroma compounds, as a function of hydrophobicity.

  9. A model for stock returns and volatility

    NASA Astrophysics Data System (ADS)

    Ma, Tao; Serota, R. A.

    2014-03-01

    We prove that Student’s t-distribution provides one of the better fits to returns of S&P component stocks and the generalized inverse gamma distribution best fits VIX and VXO volatility data. We further prove that stock returns are best fit by the product distribution of the generalized inverse gamma and normal distributions. We find Brown noise in VIX and VXO time series and explain the mean and the variance of the relaxation times on approach to the steady-state distribution.

  10. Production of volatile organohalogens by phytoplankton cultures

    SciTech Connect

    Tokarczyk, R.; Moore, R.M. (Dalhousie Univ., Halifax (Canada))

    1994-02-15

    The authors report on laboratory experiments which have demonstrated that types of unialgal cultures of marine phytoplankton can produce a range of halocarbons, including CHBr[sub 3], CHBr[sub 2]Cl, CH[sub 2]Br[sub 2]. In the laboratory environment the production rate is shown to be dependent upon the species of phytoplankton, and the development stage. Such volatile halocarbons, coming from natural sources in the seas, are thought to be important sources of reactive halogens in the troposphere, and perhaps even in the stratosphere, if the compounds are stable enough.

  11. Estimating and Forecasting Asset Volatility and Its Volatility: A Markov-Switching Range Model

    Microsoft Academic Search

    Jan Piplack

    2009-01-01

    This paper proposes a new model for modeling and forecasting the volatility of asset markets. We suggest to use the log range defined as the natural logarithm of the difference of the maximum and the minimum price observed for an asset within a certain period of time, i.e. one trading week. There is clear evidence for a regime-switching behavior of

  12. Today's "Neglected Majority"

    ERIC Educational Resources Information Center

    Risley, Rod A.

    2007-01-01

    In 1985, then American Association of Community Colleges (AACC) President Dale Parnell wrote of the "neglected majority," a phrase he coined for the astounding 70 percent of high school graduates who did not plan or aspire to attain baccalaureate degrees. Twenty-two years later, community college and public policy leaders still face the challenge…

  13. Review of the flavour-contributing volatiles and water-soluble non-volatiles in pork meat and derived products.

    PubMed

    Gorbatov, V M; Lyaskovskaya, Y N

    1980-07-01

    In relation to the problem of meat flavour, volatile and minor non-volatile components of raw, cooked and pre-cured cooked pork meat (carbonyls, sulphur compounds, volatile fatty acids, alcohols and other volatiles, nucleotides and their decomposition products, free fatty acids) are considered. Quantitative changes in some of the components, as effected by technological treatments such as heating, curing and curing and heating, are compared. The possibility of evaluating the quality of heated cured pork products by the hydrogen sulphide/mercaptan ratio is indicated. PMID:22055701

  14. Adsorption of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates

    SciTech Connect

    Ma Fengji [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China); Liu Shuxia, E-mail: liusx@nenu.edu.cn [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China); Liang Dadong; Ren Guojian; Wei Feng; Chen Yaguang; Su Zhongmin [Key Laboratory of Polyoxometalates Science of the Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2011-11-15

    The functionalization of porous metal-organic frameworks (Cu{sub 3}(BTC){sub 2}) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N{sub 2} and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies estimated by the modified Clausius-Clapeyron equation provided insight into the impact of POMs and alkali metal cations on the adsorption of VOCs. The introduction of POMs not only improved the stability, but also brought the increase of adsorption capacity by strengthening the interaction with gas molecules. Furthermore, the exchanged alkali metal cations acted as active sites to interact with adsorbates and enhanced the adsorption of VOCs. - Graphical Abstract: The adsorption behavior of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates has been systematically evaluated. Highlights: > Functionalization of MOFs was achieved by incorporating Keggin-type POMs. > Introduction of POMs improved the thermal stability and adsorption capacity. > Alkali metal ion-exchange modified the inclusion state and also enhanced the adsorption. > Adsorption enthalpies were estimated to study the impact of POMs and alkali metal cations.

  15. Use of the Analysis of the Volatile Faecal Metabolome in Screening for Colorectal Cancer

    PubMed Central

    2015-01-01

    Diagnosis of colorectal cancer is an invasive and expensive colonoscopy, which is usually carried out after a positive screening test. Unfortunately, existing screening tests lack specificity and sensitivity, hence many unnecessary colonoscopies are performed. Here we report on a potential new screening test for colorectal cancer based on the analysis of volatile organic compounds (VOCs) in the headspace of faecal samples. Faecal samples were obtained from subjects who had a positive faecal occult blood sample (FOBT). Subjects subsequently had colonoscopies performed to classify them into low risk (non-cancer) and high risk (colorectal cancer) groups. Volatile organic compounds were analysed by selected ion flow tube mass spectrometry (SIFT-MS) and then data were analysed using both univariate and multivariate statistical methods. Ions most likely from hydrogen sulphide, dimethyl sulphide and dimethyl disulphide are statistically significantly higher in samples from high risk rather than low risk subjects. Results using multivariate methods show that the test gives a correct classification of 75% with 78% specificity and 72% sensitivity on FOBT positive samples, offering a potentially effective alternative to FOBT. PMID:26086914

  16. Volatility and Uncertainty in Environmental Policy

    NASA Astrophysics Data System (ADS)

    Maniloff, Peter Taylor

    Environmental policy is increasingly implemented via market mechanisms. While this is in many ways a great success for the economics profession, a number of questions remain. In this dissertation, I empirically explore the question of what will happen as environmental outcomes are coupled to potentially volatile market phenomena, whether policies can insulate environmental outcomes and market shocks, and policymakers should act to mitigate such volatility. I use a variety of empirical methods including reduced form and structural econometrics as well as theoretical models to consider a variety of policy, market, and institutional contexts. The effectiveness of market interventions depends on the context and on the policy mechanism. In particular, energy markets are characterized by low demand elasticities and kinked supply curves which are very flat below a capacity constraint (elastic) and very steep above it (inelastic). This means that a quantity-based policy that acts on demand, such as releasing additional pollution emission allowances from a reserved fund would be an effective way to constrain price shocks in a cap-and-trade system. However, a quantity-based policy that lowers the need for inframarginal supply, such as using ethanol as an oil product substitute to mitigate oil shocks, would be ineffective. Similarly, the benefits of such interventions depends on the macroeconomic impacts of price shocks from the sector. Relatedly, I show that a liability rule designed to reduce risk from low-probability, high-consequence oil spills have very low compliance costs.

  17. Volatile biomarkers from human melanoma cells.

    PubMed

    Kwak, Jae; Gallagher, Michelle; Ozdener, Mehmet Hakan; Wysocki, Charles J; Goldsmith, Brett R; Isamah, Amaka; Faranda, Adam; Fakharzadeh, Steven S; Herlyn, Meenhard; Johnson, A T Charlie; Preti, George

    2013-07-15

    Dogs can identify, by olfaction, melanoma on the skin of patients or melanoma samples hidden on healthy subjects, suggesting that volatile organic compounds (VOCs) from melanoma differ from those of normal skin. Studies employing gas chromatography-mass spectrometry (GC-MS) and gas sensors reported that melanoma-related VOCs differed from VOCs from normal skin sources. However, the identities of the VOCs that discriminate melanoma from normal skin were either unknown or likely derived from exogenous sources. We employed solid-phase micro-extraction, GC-MS and single-stranded DNA-coated nanotube (DNACNT) sensors to examine VOCs from melanoma and normal melanocytes. GC-MS revealed dozens of VOCs, but further analyses focused on compounds most likely of endogenous origin. Several compounds differed between cancer and normal cells, e.g., isoamyl alcohol was higher in melanoma cells than in normal melanocytes but isovaleric acid was lower in melanoma cells. These two compounds share the same precursor, viz., leucine. Melanoma cells produce dimethyldi- and trisulfide, compounds not detected in VOCs from normal melanocytes. Furthermore, analyses of the total volatile metabolome from both melanoma cells and normal melanocytes by DNACNT sensors, coupled with the GC-MS results, demonstrate clear differences between these cell systems. Consequently, monitoring of melanoma VOCs has potential as a useful screening methodology. PMID:23770738

  18. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect

    John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

    2002-06-01

    Western Research Institute (WRI) initiated exploratory work towards the development of new field screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of carbon-halogen bonds. Commercially available heated diode and corona discharge leak detectors were procured and evaluated for halogenated VOC response. The units were modified to provide a digital readout of signal related to VOC concentration. Sensor response was evaluated with carbon tetrachloride and tetrachloroethylene (perchloroethylene, PCE), which represent halogenated VOCs with and without double bonds. The response characteristics were determined for the VOCs directly in headspace in Tedlar bag containers. Quantitation limits in air were estimated. Potential interferences from volatile hydrocarbons, such as toluene and heptane, were evaluated. The effect of humidity was studied also. The performance of the new devices was evaluated in the laboratory by spiking soil samples and monitoring headspace for halogenated VOCs. A draft concept of the steps for a new analytical method was outlined. The results of the first year effort show that both devices show potential utility for future analytical method development work towards the goal of developing a portable test kit for screening halogenated VOCs in the field.

  19. Small ion concentration in houses with enhanced radon concentration

    Microsoft Academic Search

    G. Graeffe; J. Keskinen; M. Lehtimaeki

    1989-01-01

    The concentration of radon, small air ions, and aerosol particles were measured continuously in 16 Finnish dwellings. As expected, radon was found to be the major source for small ion generation in indoor air. A simple model for the relationship between ion concentration and radon concentration is tested. The parameters of the model are the ion production rate from radon

  20. Ion colliders

    SciTech Connect

    Fischer, W.

    2011-12-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the RHIC and LHC injector chains for the heaviest ion species used to date. The RHIC pulsed sputter source (PSC) and Tandem electrostatic accelerator are being replaced by an Electron Beam Ion Source (EBIS), Radio Frequency Quadrupole (RFQ) and short linac [08Ale1]. With EBIS beams of any element can be prepared for RHIC including uranium and spin-polarized 3He. At CERN an ECR ion source is used, followed by an RFQ and Linac. The ions are then accumulated, electron cooled, and accelerated in LEIR. After transfer to and acceleration in the PS, ion beams are injected into the SPS.