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1

Major Odorants Released as Urinary Volatiles by Urinary Incontinent Patients  

PubMed Central

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.

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

2013-01-01

2

Major odorants released as urinary volatiles by urinary incontinent patients.  

PubMed

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

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

2013-07-03

3

Differential Binding between Volatile Ligands and Major Urinary Proteins Due to Genetic Variation in Mice.  

National Technical Information Service (NTIS)

Two different structural classes of chemical signals in mouse urine, i.e., volatile organic compounds (VOCs) and the major urinary proteins (MUPs), interact closely because MUPs sequester VOCs. Although qualitative and/or quantitative differences in each ...

C. C. Grigsby G. Preti J. Kwak M. Koksal M. M. Rizki

2012-01-01

4

Major ions in Spitsbergen snow samples  

NASA Astrophysics Data System (ADS)

Chemical analysis of Spitsbergen snow cores sampled in spring 1983, reveals a spatial pattern consistent with orographic deposition of major anthropogenic pollutants with air movements from southeast towards northwest. The highest concentrations of pollutant species were found at an altitude of 700 metres above sea level, and are higher than for any other recorded snow samples from the Arctic.

Semb, A.; Brækkan, R.; Joranger, E.

5

Major ions in spitsbergen snow samples  

SciTech Connect

Chemical analysis of Spitsbergen snow cores sampled in spring 1983, reveals a spatial pattern consistent with orographic deposition of major anthropogenic pollutants with air movements from southeast towards northwest. The highest concentrations of pollutant species were found at an altitude of 700 metres above sea level, and are higher than for any other recorded snow samples from the Arctic.

Semb, A.; Braekkan, R.; Joranger, E.

1984-05-01

6

Major ions in spitsbergen snow samples  

Microsoft Academic Search

Chemical analysis of Spitsbergen snow cores sampled in spring 1983, reveals a spatial pattern consistent with orographic deposition of major anthropogenic pollutants with air movements from southeast towards northwest. The highest concentrations of pollutant species were found at an altitude of 700 metres above sea level, and are higher than for any other recorded snow samples from the Arctic.

A. Semb; R. Braekkan; E. Joranger

1984-01-01

7

Procedure for determination of trace ions in boric acid by matrix volatilization-ion chromatography.  

PubMed

A method for determination of anions and cations in boric acid is proposed by matrix volatilization. The boric acid matrix was eliminated as trimethyl borate ester in a vapour phase matrix elimination (VPME) system using a mixture of glycerol-methanol. In this VPME system, in situ reagent purification, sample decomposition and digest evaporation were achieved in a single step. Trace anions were separated on anion-exchange column (IonPac AS17) by an isocratic elution with 15 mM sodium hydroxide and the cations on a cation-exchange column (IonPac CS12) by 20 mM hydrochloric acid as eluents. Method detection limits (3sigma) for most ions ranged from 0.3 to 8 ng/g (ppb). Recovery experiments combined with comparison of data obtained by other methods were employed to verify the accuracy of the proposed method. Application of the method to determine trace levels of anions like acetate, oxalate, sulfate, phosphate and cations such as lithium, sodium, potassium, magnesium and calcium in two highly pure grades of boric acid using ion chromatography is demonstrated. PMID:12885085

Dash, K; Karunasagar, D; Thangavel, S; Chaurasia, S C

2003-06-20

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

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.

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

10

Direct determination of volatile analytes from solid samples by UV-ion mobility spectrometry  

Microsoft Academic Search

A simple, reliable, inexpensive sample introduction system (SIS) coupled to an ion mobility spectrometry (IMS) equipment was used for the determination of volatile analytes present in solid samples. Following minimal pretreatment, the solid sample (e.g. fish) is directly placed in a membrane unit and released analytes (trimethylamine, dimethylamine and ammonia) pass through the membrane into a nitrogen acceptor stream; finally,

M. Menéndez; R. Garrido-Delgado; L. Arce; M. Valcárcel

2008-01-01

11

Erosion of volatile elemental condensed gases by keV electron and light-ion bombardment.  

National Technical Information Service (NTIS)

Erosion of the most volatile elemental gases by keV electron and light-ion bombardment has been studied at the experimental setup at Risoe. The present work includes frozen neon, argon, krypton, nitrogen, oxygen and three hydrogen isotopes, deuterium, hyd...

J. Schou

1991-01-01

12

Determination of major volatile compounds during the production of fruit vinegars by static headspace gas chromatography–mass spectrometry method  

Microsoft Academic Search

A static headspace gas chromatography coupled to mass spectrometry (SHS–GC–MS) method was validated to determine several major volatile components during the production process of fruit vinegars. The method is simple, fast, linear in the working range, suitably sensitive, repeatable and reproducible, and has a good degree of accuracy for most of the compounds studied. Different conditions were tested in the

C. Ubeda; R. M. Callejón; C. Hidalgo; M. J. Torija; A. Mas; A. M. Troncoso; M. L. Morales

2011-01-01

13

Ion-trap detection of volatile organic compounds in alveolar breath  

SciTech Connect

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.

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

1992-01-01

14

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

PubMed

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

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

2011-04-12

15

Characteristics of major volatile organic hazardous air pollutants in the urban air of Kaohsiung city  

Microsoft Academic Search

The concentrations and characteristics of volatile organic hazardous air pollutants (HAPs) in the urban city of Kaohsiung\\u000a from motor vehicles and dense pollutant sources has become a national concern. To continuously monitor volatile organic HAPs,\\u000a sampling sites were selected near the four air-quality monitoring stations established by Ethe nvironmental Protection Administration\\u000a of Taiwan ROC, namely Nan-tz, Tso-ying, San-min and Hsiao-kang,

Mei-Chuan Huang; Jim Juimin Lin

2007-01-01

16

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

SciTech Connect

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.

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

1988-09-01

17

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

Microsoft Academic Search

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

W. Jeno; Richard Bassette; Richard E. Crang

1988-01-01

18

Major inorganic ions in North Pole snow samples  

SciTech Connect

Major inorganic ions, pH, total N and P were analyzed in eight arctic snow samples collected in March, April and May 1984 during an expedition in the North Pole region (N83/sup 0/18' W73/sup 0/06' - N89.960/sup 0/). The concentrations of the ions of different samples were close to each other and the values obtained seem to be representative for mean concentrations in the snow. In the sample taken from the North Pole the pH value was 5.00 while the H/sup +/-, SO/sub 4//sup 2 -/- and NO/sub 3//sup -/-concentrations were 0.24, 6.2, and 4.3 ..mu..mol/l respectively. The concentrations are exceedingly low and agree very well with earlier results from arctic snow samples.

Karlsson, V.; Haesaenen, E.; Nordlund, O.P.

1985-01-01

19

The major-ion composition of silurian seawater  

NASA Astrophysics Data System (ADS)

One-hundred fluid inclusions in Silurian marine halite were analyzed in order to determine the major-ion composition of Silurian seawater. The samples analyzed were from three formations in the Late Silurian Michigan Basin, the A-1, A-2, and B Evaporites of the Salina Group, and one formation in the Early Silurian Canning Basin (Australia), the Mallowa Salt of the Carribuddy Group. The results indicate that the major-ion composition of Silurian seawater was not the same as present-day seawater. The Silurian ocean had lower concentrations of Mg 2+, Na +, and SO 42-, and much higher concentrations of Ca 2+ relative to the ocean's present-day composition. Furthermore, Silurian seawater had Ca 2+ in excess of SO 42-. Evaporation of Silurian seawater of the composition determined in this study produces KCl-type potash minerals that lack the MgSO 4-type late stage salts formed during the evaporation of present-day seawater. The relatively low Na + concentrations in Silurian seawater support the hypothesis that oscillations in the major-ion composition of the oceans are primarily controlled by changes in the flux of mid-ocean ridge brine and riverine inputs and not global or basin-scale, seawater-driven dolomitization. The Mg 2+/Ca 2+ ratio of Silurian seawater was ˜1.4, and the K +/Ca 2+ ratio was ˜0.3, both of which differ from the present-day counterparts of 5 and 1, respectively. Seawaters with Mg 2+/Ca 2+ <2 facilitate the precipitation of low-magnesian calcite (mol % Mg < 4) marine ooids and submarine carbonate cements whereas seawaters with Mg 2+/Ca 2+ >2 (e.g., modern seawater) facilitate the precipitation of aragonite and high-magnesian calcite. Therefore, the early Paleozoic calcite seas were likely due to the low Mg 2+/Ca 2+ ratio of seawater, not the pCO 2 of the Silurian atmosphere.

Brennan, Sean T.; Lowenstein, Tim K.

2002-09-01

20

Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments  

SciTech Connect

The theoretical potential for the formation of clusters of vapor-phase organic compounds found in indoor air around the [sup 218]PoO[sub x][sup +] ion was investigated as well as which compounds were most likely to form clusters. A compilation of measurements of indoor organic compounds has been made for future experiments and theoretical calculations by the radon research community. Forty-four volatile and semivolatile organic compounds out of the more than 300 that have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the [sup 218]PoO[sub x][sup +] ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones, and the acetates) and the semivolatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos). Although the estimated diameters are consistent with the measured diameters for the unattached fraction, the state of experimental and theoretical knowledge in this area is not sufficiently developed to judge the quantitative validity of these predictions. 48 refs., 1 fig., 5 tabs.

Daisey, J.M. (Lawrence Berkeley Lab., CA (United States)); Hopke, P.K. (Clarkson Univ., Potsdam, NY (United States))

1993-07-01

21

The major-ion composition of Permian seawater  

NASA Astrophysics Data System (ADS)

The major-ion (Mg2+, Ca2+, Na+, K+, SO42-, and Cl-) composition of Permian seawater was determined from chemical analyses of fluid inclusions in marine halites. New data from the Upper Permian San Andres Formation of Texas (274 272 Ma) and Salado Formation of New Mexico (251 Ma), analyzed by the environmental scanning electron microscopy (ESEM) X-ray energy-dispersive spectrometry (EDS) method, along with published chemical compositions of fluid inclusions in Permian marine halites from North America (two formations of different ages) and the Central and Eastern European basins (eight formations of four different ages) show that Permian seawater shares chemical characteristics with modern seawater, including SO42- > Ca2+ at the point of gypsum precipitation, evolution into Mg2+-Na+-K+-SO42--Cl- brines, and Mg2+/K+ ratios ˜5. Permian seawater, however, is slightly depleted in SO42- and enriched in Ca2+, although modeling results do not rule out Ca2+ concentrations close to those in present-day seawater. Na+ and Mg2+ in Permian seawater are close to (slightly below) their concentrations in modern seawater. Permian and modern seawater are both classified as aragonite seas, with Mg2+/Ca2+ ratios >2, conditions favorable for precipitation of aragonite and magnesian calcite as ooids and cements. The chemistry of Permian seawater was modeled using the chemical composition of brine inclusions for three periods: Lower Permian Asselian-Sakmarian (296 283 Ma), Lower Permian Artinskian-Kungurian (283 274 Ma), and Upper Permian Tatarian (258 251 Ma). Parallel changes in the chemistry of brine inclusions from equivalent age evaporites in North America, Central Europe, and Eastern Europe show that seawater underwent secular variations in chemistry over the 50 million years of the Permian. Modeled SO42- concentrations are 20 mmol per kg H2O (mmolal) and 19 mmolal in the Asselian-Sakmarian and Artinskian-Kungurian, with higher concentrations in the Upper Permian Tatarian (23 mmolal). Modeled Ca2+ is at or above its concentration in modern seawater throughout the Permian. Mg2+ is close to (slightly below) its concentration in modern seawater (55 mmolal) in the Asselian-Sakmarian (52 mmolal), and Tatarian (52 mmolal), but slightly higher than modern seawater in the Artinskian-Kungurian (60 mmolal). Mg2+/Ca2+ ratios are 3.5 (total range = 2.7 to 5.5) in the Lower Permian and rose slightly to 3.7 (total range = 3.1 to 5.8) in the Upper Permian, primarily due to decreases in Ca2+. These results are consistent with models that predict oscillations in the major-ion composition of Phanerozoic seawater on the basis of changes in the midocean ridge/river water flux ratio driven by changes in the rate of midocean ridge crust production. The Permian was characterized by low sea levels, icehouse conditions, and southern hemisphere glaciation. Such conditions, analogous to the present ice age, and the similarities between Permian seawater and modern seawater, all suggest that general Phanerozoic supercycles, driven by mantle convection and global volcanicity, also control the major-ion chemistry of seawater.

Lowenstein, Tim K.; Timofeeff, Michael N.; Kovalevych, Volodymyr M.; Horita, Juske

2005-04-01

22

The Major-ion Composition of Permian Seawater  

SciTech Connect

The major-ion (Mg{sup 2+}, Ca{sup 2+}, Na{sup +}, K{sup +}, SO{sub 4}{sup 2-}, and Cl{sup -}) composition of Permian seawater was determined from chemical analyses of fluid inclusions in marine halites. New data from the Upper Permian San Andres Formation of Texas (274--272 Ma) and Salado Formation of New Mexico (251 Ma), analyzed by the environmental scanning electron microscopy (ESEM) X-ray energy-dispersive spectrometry (EDS) method, along with published chemical compositions of fluid inclusions in Permian marine halites from North America (two formations of different ages) and the Central and Eastern European basins (eight formations of four different ages) show that Permian seawater shares chemical characteristics with modern seawater, including SO{sub 4}{sup 2-} > Ca{sup 2+} at the point of gypsum precipitation, evolution into Mg{sup 2+}-Na{sup +}-K{sup +}-SO{sub 4}{sup 2-}-Cl{sup -} brines, and Mg{sup 2+}/K{sup +} ratios {approx} 5. Permian seawater, however, is slightly depleted in SO{sub 4}{sup 2-} and enriched in Ca{sup 2+}, although modeling results do not rule out Ca{sup 2+} concentrations close to those in present-day seawater. Na{sup +} and Mg{sup 2+} in Permian seawater are close to (slightly below) their concentrations in modern seawater. Permian and modern seawater are both classified as aragonite seas, with Mg{sup 2+}/Ca{sup 2+} ratios >2, conditions favorable for precipitation of aragonite and magnesian calcite as ooids and cements. The chemistry of Permian seawater was modeled using the chemical composition of brine inclusions for three periods: Lower Permian Asselian-Sakmarian (296--283 Ma), Lower Permian Artinskian-Kungurian (283--274 Ma), and Upper Permian Tatarian (258--251 Ma). Parallel changes in the chemistry of brine inclusions from equivalent age evaporites in North America, Central Europe, and Eastern Europe show that seawater underwent secular variations in chemistry over the 50 million years of the Permian. Modeled SO{sub 4}{sup 2-} concentrations are 20 mmol per kg H{sub 2}O (mmolal) and 19 mmolal in the Asselian-Sakmarian and Artinskian-Kungurian, with higher concentrations in the Upper Permian Tatarian (23 mmolal). Modeled Ca{sup 2+} is at or above its concentration in modern seawater throughout the Permian. Mg{sup 2+} is close to (slightly below) its concentration in modern seawater (55 mmolal) in the Asselian-Sakmarian (52 mmolal), and Tatarian (52 mmolal), but slightly higher than modern seawater in the Artinskian-Kungurian (60 mmolal). Mg{sup 2+}/Ca{sup 2+} ratios are 3.5 (total range = 2.7 to 5.5) in the Lower Permian and rose slightly to 3.7 (total range = 3.1 to 5.8) in the Upper Permian, primarily due to decreases in Ca{sup 2+}. These results are consistent with models that predict oscillations in the major-ion composition of Phanerozoic seawater on the basis of changes in the midocean ridge/river water flux ratio driven by changes in the rate of midocean ridge crust production. The Permian was characterized by low sea levels, icehouse conditions, and southern hemisphere glaciation. Such conditions, analogous to the present ice age, and the similarities between Permian seawater and modern seawater, all suggest that general Phanerozoic supercycles, driven by mantle convection and global volcanicity, also control the major-ion chemistry of seawater.

Lowenstein, T K. [State University of New York, Binghamton; Timofeeff, Michael N. [State University of New York, Binghamton; Kovalevych, Volodymyr M. [National Academy of Sciences of Ukraine, Naukova, Ukraine; Horita, Juske [ORNL

2005-01-01

23

Land application of municipal landfill leachate: fate of ions and ammonia volatilization.  

PubMed

Landfill leachates are pollutants rich in ammoniacal N, Na, and K, but land application potentially offers an alternative for recycling these leachate nutrients. We applied landfill leachate corresponding to 0, 110, 220, 330, and 440 kg ha of total N, divided in three applications (July, August, and October 2008), onto the surface of an acidic (pH 5.5-6.0) clay (79% clay) Ultisol and monitored NH volatilization just after applications and microbiological (0-10 cm) and chemical attributes (0-60-cm soil depth) in August 2008, January 2009, and May 2009. Ammonium (up to 30 mg kg), NO (up to 160 mg kg), Na, K (up to 1.1 cmol kg each), and electrical conductivity (up to 1 dS m) increased transiently in soil following applications. Despite >90% of the total leachate N being ammoniacal, NO predominated in the first soil sampling, 14 d after the second application, suggesting fast nitrification, but it decreased in the soil profile thereafter. From 5 to 25% of the total applied N volatilized as NH, with maximum losses within the first 3 d. Applications inhibited (50%) the relative nitrification rate and increased (50%) hot-water-soluble carbohydrates in the soil at the highest rate. No effects were observed on soil microbial biomass C (114-205 mg kg) and activity (5-8 mg CO-C kg d) or on corn grain yields (6349-7233 kg ha). Controlled land application seems to be a viable alternative for landfill leachate management, but NO leaching, NH volatilization, and accumulation of salinizing ions must be monitored in the long term to prevent environmental degradation. PMID:23673845

Santos, C A; Panchoni, L C; Bini, D; Kuwano, B H; Carmo, K B; Silva, S M C P; Martines, A M; Andrade, G; Andrade, D S; Cardoso, E J B N; Zangaro, W; Nogueira, M A

24

Determination of volatile fatty acids in landfill leachates by ion-exclusion chromatography.  

PubMed

An ion-exclusion chromatographic method with on-line desalinization for the determination of volatile fatty acids in landfill leachates is described. Highly sensitive conductivity detection of the organic acids was achieved by using dilute p-hydroxybenzoic acid solution as an eluent. Interference with mineral acids was reduced by treatment with barium chloride solution prior to desalinization. A silver-loaded cation-exchange guard column for the desalinization was installed in series with the analytical column to avoid the contamination of organic acids. This method features detection limits of 0.01 mg L(-1) formic acid, 0.02 mg L(-1) acetic acid, 0.05 mg L(-1) propionic acid, and 0.1 mg L(-1) butyric acid, respectively, with an injection of 20 microL sample. Application of the on-line desalinization LC method is illustrated for leachate samples from a Japanese sanitary landfill. PMID:15334921

Yamamoto, Atsushi; Yasuhara, Akio; Kodama, Shuji; Matsunaga, Akinobu; Suzuki, Shigeru; Mohri, Shino; Yamada, Masato

2004-03-01

25

Major ion toxicity in effluents: A review with permitting recommendations  

SciTech Connect

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.

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

26

IVO, a device for In situ Volatilization and On-line detection of products from heavy ion reactions  

NASA Astrophysics Data System (ADS)

A new gaschromatographic separation system to rapidly isolate heavy ion reaction products in the form of highly volatile species is described. Reaction products recoiling from the target are stopped in a gas volume and converted in situ to volatile species, which are swept by the carrier gas to a chromatography column. Species that are volatile under the given conditions pass through the column. In a cluster chamber, which is directly attached to the exit of the column, the isolated volatile species are chemically adsorbed to the surface of aerosol particles and transported to an on-line detection system. The whole set-up was tested using short-lived osmium (Os) and mercury (Hg) nuclides produced in heavy ion reactions to model future chemical studies with hassium (Hs, /Z=108) and element 112. By varying the temperature of the isothermal section of the chromatography column between room temperature and -80°C, yield measurements of given species can be conducted, yielding information about the volatility of the investigated species.

Düllmann, Ch. E.; Eichler, B.; Eichler, R.; Gäggeler, H. W.; Jost, D. T.; Piguet, D.; Türler, A.

2002-03-01

27

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

SciTech Connect

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.

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

28

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

PubMed

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

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

2011-02-26

29

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

Microsoft Academic Search

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)

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

1997-01-01

30

Analysis of volatile components of drugs and explosives by solid phase microextraction-ion mobility spectrometry.  

PubMed

Current ion mobility spectrometry (IMS) devices are used to detect drugs and explosives in the form of particles and, in cases where the vapor pressure of the drugs or explosives is sufficiently high, the gas can be sampled and detected directly. The aim of this study is to demonstrate the use of solid phase microextraction (SPME) as a preconcentration technique coupled to an IMS for the detection of odor signature compounds of drugs and explosives. The reduced mobilities (K(o)) and IMS operating conditions for the odor signature compounds of cocaine, marijuana, and 3,4-methylenedioxy-N-methylamphetamine (MDMA) are reported for the first time. LODs, linear dynamic ranges (LDRs), and the precision of the analysis of these odor signature compounds, and the explosive taggant 2,3-dimethyl-2,3-dinitrobutane (DMNB) were obtained by SPME-IMS and normal IMS conditions. The systematic optimization of the IMS operating parameters for the detection of these odor compounds is also reported incorporating the use of genetic algorithms (GAs) for finding the optimal settings for the detection of these compounds of interest. These results support the case for targeting volatile components as a presumptive detection for the presence of the parent compounds of drugs and explosives. Furthermore, the IMS-specific GA developed can be used as an optimization tool for the detection of other compounds of interest in future work. PMID:18196520

Lai, Hanh; Guerra, Patricia; Joshi, Monica; Almirall, José R

2008-02-01

31

A quantitative study of biogenic volatile organic compounds using proton transfer reaction linear ion trap mass spectrometry  

Microsoft Academic Search

Currently, proton-transfer reaction mass spectrometry (PTR-MS) allows for quantitative determination of volatile organic compounds in real time at concentrations in the low ppt range, but cannot differentiate isomers or isobaric molecules, using the conventional quadrupole mass filter. Here we pursue the application of linear quadrupole ion trap (LIT) mass spectrometry in combination with proton-transfer reaction chemical ionization to provide the

Levi H Mielke

2009-01-01

32

Characteristics of major secondary ions in typical polluted atmospheric aerosols during autumn in central Taiwan.  

PubMed

In autumn of 2008, the chemical characteristics of major secondary ionic aerosols at a suburban site in central Taiwan were measured during an annually occurring season of high pollution. The semicontinuous measurement system measured major soluble inorganic species, including NH(4)(+), NO(3)(-), and SO(4)(2-), in PM(10) with a 15 min resolution time. The atmospheric conditions, except for the influences of typhoons, were dominated by the local sea-land breeze with clear diurnal variations of meteorological parameters and air pollutant concentrations. To evaluate secondary aerosol formation at different ozone levels, daily ozone maximum concentration (O(3,daily max)) was used as an index of photochemical activity for dividing between the heavily polluted period (O(3,daily max) ?80 ppb) and the lightly polluted period (O(3,daily max)<80 ppb). The concentrations of PM(10), NO(3)(-), SO(4)(2-), NH(4)(+) and total major ions during the heavily polluted period were 1.6, 1.9, 2.4, 2.7 and 2.3 times the concentrations during the lightly polluted period, respectively. Results showed that the daily maximum concentrations of PM(10) occurred around midnight and the daily maximum ozone concentration occurred during daytime. The average concentration of SO(2) was higher during daytime, which could be explained by the transportation of coastal industry emissions to the sampling site. In contrast, the high concentration of NO(2) at night was due to the land breeze flow that transport inland urban air masses toward this site. The simulations of breeze circulations and transitions were reflected in transports and distributions of these pollutants. During heavily polluted periods, NO(3)(-) and NH(4)(+) showed a clear diurnal variations with lower concentrations after midday, possibly due to the thermal volatilization of NH(4)NO(3) during daytime and transport of inland urban plume at night. The diurnal variation of PM(10) showed the similar pattern to that of NO(3)(-) and NH(4)(+) aerosols. This indicated that the formatted secondary aerosols in the inland urban area could be transported to the coastal area by the weak land breeze and deteriorated the air quality in the coastal area at night. PMID:21320743

Fang, Guor-Cheng; Lin, Shih-Chieh; Chang, Shih-Yu; Lin, Chuan-Yao; Chou, Charles-C K; Wu, Yun-Jui; Chen, Yu-Chieh; Chen, Wei-Tzu; Wu, Tsai-Lin

2011-02-12

33

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

NASA Astrophysics Data System (ADS)

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 possible involvement of species other than sulfuric acid in the nucleation process remain controversial. Here we study the particle formation and growth processes in the troposphere using a global chemical transport model (GEOS-Chem) with an advanced particle microphysics (APM) module incorporated. The widely used 2-product secondary organic aerosol (SOA) formation model has been extended to take into account the volatility changes of secondary organic gases (SOGs) arising from the aging process. In addition to semi-volatile SOG (SV-SOG) and medium-volatile SOG (MV-SOG), we add a third component representing low-volatile SOG (LV-SOG) and design a scheme to transfer MV-SOG to SV-SOG and SV-SOG to LV-SOG associated with oxidation aging. The co-condensation of H2SO4 and LV-SOG on particles is explicitly simulated in GEOS-Chem + APM. Our predicted LV-SOG concentrations are generally a factor of ~2-20 higher than those of [H2SO4], and LV-SOG condensation significantly enhances particle growth rates and SOA mass over many parts of the continents. We show that ion-mediated nucleation appears to be able to capture within a factor of ~ 2 the particle number concentrations measured around the globe. Comparisons of the simulated and observed evolution of particle size distributions at selected sites clearly show that LV-SOG condensation is critical in order to bring the simulations closer to the observations. Ion-mediated nucleation and LV-SOG condensation substantially increase the concentration of cloud condensation nuclei. The ability of GEOS-Chem +APM in explaining the seasonal and the diurnal variations of particle size distributions and number concentrations at a number of locations will be assessed and implications will be discussed.

Yu, F.; Luo, G.

2010-12-01

34

Analysis of Ambient Polar Volatile Organic Compounds Using Chemical Ionization-Ion Trap Detector.  

National Technical Information Service (NTIS)

The current approach to measuring trace levels of volatile organic compounds (VOCs) in ambient air requires cryogenic trapping of the analytes, followed by thermal desorption and low-temperature refocusing onto a column for analysis by capillary gas chrom...

S. M. Gordon M. Miller

1989-01-01

35

Zonation of volatile and major elements in basaltic melt inclusions: a snapshot of syn-eruptive processes  

NASA Astrophysics Data System (ADS)

Significant zonation in volatile and major elements has been discovered in olivine-hosted melt inclusions (MIs) from glassy pillow margins from the Siqueiros Fracture Zone [samples previously studied in 1]. For the most part, components that are compatible in olivine (e.g. MgO) are depleted at the edges of the zoned MIs relative to their centers, whereas components that are incompatible in olivine (e.g. Al2O3, SiO2, Na2O, and S) are enriched near the MI edges. H2O and F are exceptions in that they are incompatible, yet in several MIs they are depleted near the olivine-melt boundary. FeO and CaO are also exceptions in that they show complex features attributable to uphill diffusion. Another complexity is the similarity between the shapes of the SiO2 and Na2O profiles (despite significant differences in measured self and tracer diffusivities of these components [2, 3]), suggesting that the diffusion of these components is strongly coupled. All MIs from this sample suite exhibit zoning profiles, as do a suite of MIs from the Galapagos Islands and the inclusions studied in [4], so this feature may be common in rapidly quenched, glassy inclusions. Preservation of strong zonation in the Siqueiros MIs suggests that it formed in response to crystallization of olivine on the walls of the MIs during or just prior to eruption because, based on known diffusion coefficients, such profiles would be erased by diffusion on time scales on the order of 1 hr. The MgO concentration profiles in several Siqueiros MIs have been used to constrain the cooling history of the inclusions using the results of [5]. The profiles are consistent with an initial slow cooling rate followed by a period of more rapid cooling over a total timescale of ~10 min. Given that they are incompatible in olivine, the observed decreases in the concentrations of H2O and F toward the edges of some Siqueiros inclusions could suggest either uphill diffusion of H2O and F (as observed for H2O in [6] in a granitic composition) or loss of H2O and F into/through the host olivine (observed for H2O in [7-9]). The latter hypothesis would complement the results of [10], who observed elevated H2O and F in olivine adjacent to volatile-rich MIs. [1] Saal et al. (2002) Nature, 419, 451-455. [2] Lesher et al. (1996) Geochimica et Cosmochimica Acta, 60, 405-413. [3] Jambon (1982) Journal of Geophysical Research, 87, 10797-10810. [4] Mercier (2009) PhD thesis, Université Paris - Sud 11. [5] Chen & Zhang (2008) GCA, 72, 4756-4777. [6] Mungall et al. (1998) American Mineralogist, 83, 685-699. [7] Hauri (2002) Chemical Geology, 183, 115-141. [8] Massare et al. (2002) Chemical Geology, 183, 87-98. [9] Portnyagin et al. (2008) EPSL, 272, 541-552. [10] Le Voyer et al. (2010) AGU abstract #V23E-07.

Newcombe, M.; Fabbrizio, A.; Zhang, Y.; Le Voyer, M.; Guan, Y.; Ma, C.; Eiler, J. M.; Saal, A. E.; Stolper, E. M.

2011-12-01

36

Major Ion Geochemistry of Nam Co Lake and its Sources, Tibetan Plateau  

Microsoft Academic Search

The major cations and anions from lake water samples and its sources, including glacier snow, precipitation, stream, and swamp\\u000a water in the Nam Co basin, central Tibetan Plateau, were studied. The concentrations of the major ions varied significantly\\u000a in the five environmental matrices. Generally, the mean concentrations of most ions are in the order of lake water > swamp\\u000a water > stream water > precipitation > snow. Rock

Qianggong Zhang; Shichang Kang; Feiyue Wang; Chaoliu Li; Yanwei Xu

2008-01-01

37

Detection of characteristic metabolites of Aspergillus fumigatus and Candida species using ion mobility spectrometry-metabolic profiling by volatile organic compounds.  

PubMed

Volatile metabolites of Aspergillus fumigatus and Candida species can be detected by gas chromatography/mass spectrometry (GC/MS). A multi-capillary column - ion mobility spectrometer (MCC-IMS) was used in this study to assess volatile organic compounds (VOCs) in the headspace above A. fumigatus and the four Candida species Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis in an innovative approach, validated for A. fumigatus and C. albicans by GC/MS analyses. For the detection of VOCs, a special stainless steel measurement chamber for the microbial cultures was used. The gas outlet was either attached to MCC-IMS or to adsorption tubes (Tenax GR) for GC/MS measurements. Isoamyl alcohol, cyclohexanone, 3-octanone and phenethylalcohol can be described as discriminating substances by means of GC/MS. With MCC-IMS, the results for 3-octanone and phenethylalcohol are concordant and additionally to GC/MS, ethanol and two further compounds (p_0642_1/p_683_1 and p_705_3) can be described. Isoamyl alcohol and cyclohexanone were not properly detectable with MCC-IMS. The major advantage of the MCC-IMS system is the feasibility of rapid analysis of complex gas mixtures without pre-concentration or preparation of samples and regardless of water vapour content in an online setup. Discrimination of fungi on genus level of the investigated germs by volatile metabolic profile and therefore detection of VOC is feasible. However, a further discrimination on species level for Candida species was not possible. PMID:21668516

Perl, Thorsten; Jünger, Melanie; Vautz, Wolfgang; Nolte, Jürgen; Kuhns, Martin; Borg-von Zepelin, Margarete; Quintel, Michael

2011-06-12

38

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

NASA Astrophysics Data System (ADS)

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].

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

2003-05-01

39

Hydrous Melting Creates Lower Mean F at the Galápagos Spreading Center-- Modeling Results from A Major and Volatile Element Study  

NASA Astrophysics Data System (ADS)

The Galápagos Spreading Center (GSC) between 90°30'W and 98°W manifests its interaction with the nearby Galápagos plume by way of variations in crustal thickness, axial structure, and lava geochemistry along the ridge axis. Rock samples with average along-axis spacing of ~9 km were analyzed for major elements, S, F, Cl, H2O and CO2. To account for apparent variations in parental magmas, samples were classified as E-MORBs, T-MORBs, or N-MORBs based on K/Ti ratios of > 0.15, 0.15 to 0.09, and < 0.09, respectively. E-MORB rocks dominate the GSC east of 92.6°W, where the crust is thickest (6.5-8 km). T-MORBs are mainly found between 92.6°W and 95.5°W, where crustal thickness is 6-7 km. West of the propagating rift tip at 95.5°W, where crustal thickness is < 6 km, only N-MORBs are found. High K/Ti E-MORBs are also characterized by higher H2O, Al2O3, Na2O, Cl, and F, and lower FeO*, SiO2, and CaO/Al2O3 relative to N-MORB at similar values of MgO. Along-axis gradients in these elements peak near 91.8°W and gradually taper towards N-MORB values with increased distance from the hotspot. The compositional characteristics of higher Na2O, Al2O3, and other incompatible elements, along with lower CaO, FeO*, and CaO/Al2O3 of the E-MORBs are consistent with lower mean extents of partial melting relative to N-MORB. This apparent paradox--lower degree of melting where the crust is thickest near the hotspot--can be reconciled with a melting model that incorporates melting with the presence of volatiles. Depression of the solidus and low productivity in the hydrous melting zone expands the volume of mantle undergoing melting and thus increases the total volume of melt produced. The degree of melting in the hydrous melting region remains low, thus these melts are highly enriched in incompatible elements. These low-degree melts then combine with melts generated in the anhydrous melting region. The result is an incompatible element-rich melt drawn from a larger volume of melting but whose maximum degree of melting is similar to anhydrous melting, creating a lower mean F and thicker crust. We successfully reproduce the trends in incompatible element concentrations and crustal thickness near the Galapagos hotspot with simple calculations that include variations in the volume and productivity of the hydrous melting zone.

Cushman, B. J.; Sinton, J. M.; Ito, G.; Dixon, J. E.

2002-12-01

40

Perturbations in major ion chemistry of Taylor Slough, Everglades National Park, Florida, USA  

NASA Astrophysics Data System (ADS)

Wetland ecosystems are influenced by perturbations in the cycling of water, nutrients, and other biogeochemically active elements. The purpose of this study was focused on identifying perturbations in major ion chemistry of Taylor Slough, Everglades National Park (ENP) Florida, and to attempt to identify the sources of the perturbations. Water samples were collected from 5 Florida Coastal Everglades-Long Term Ecological Research sites located along a freshwater upland to coastal transect. Composite samples were collected every three days using an ISCO sampler, and were analyzed for major cations and anions during a two-year period ranging from 2008-2010. As expected, the surface water chemistry at the upland sites contained lower ion concentrations than the coastal sites. However, a decrease in ion concentrations at the upland sites in a downstream direction varied from an increase in ion concentration at the coastal sites. This variation may be due to retardation of the ions by sediments and vegetation and proximity to Florida Bay respectively. Seasonal differences in the ion concentrations were observed as well as episodic changes in response to the passage of hurricanes.

Sandoval, E.; Price, R. M.

2010-12-01

41

Atmospheric aerosol major ion composition and cloud condensation nuclei over the northeast Atlantic  

Microsoft Academic Search

Concentrations of the major soluble ions, non-sea-salt (nss) sulfate, nitrate, chloride, and ammonium have been measured in aerosol samples collected at various locations and altitudes over the North Atlantic Ocean. Concentrations of nss sulfate, nitrate, and ammonium were found to be fairly uniform within the maritime boundary layer in an air mass aged in the Azores anticyclone; average values obtained

Roy M. Harrison; John D. Peak; Andrew D. Kaye

1996-01-01

42

Mobilization of major inorganic ions during experimental diagenesis of characterized peats  

Microsoft Academic Search

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

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

2000-01-01

43

Sequential sampling of particles, major ions and total trace metals in wet deposition  

NASA Astrophysics Data System (ADS)

A precipitation event was sampled at a remote, coastal site at Adrigole, Ireland, during May 1988. Major ions (Cl -, NO 32-, SO 4-, H +, Na +, K +, Ca 2+, Mg 2+) showed a rapid decrease in concentration with time, with the exception of ammonium and non-sea salt sulphate. Elements of marine origin (Cl -, SO 42-, Na +, K +, Ca 2+ and Mg 2+) were positively correlated with each other ( r=0.97-1.00) but weakly correlated with rainfall intensity. Total trace metal concentrations (Al, Cd, Pb, Mn, Fe, Cu and Zn) decreased less rapidly than major ions. Single particle characterization of the insoluble matter identified Al and Si as the dominant elements and 0.2-0.4 ?m diamter as the median size range. Selective removal mechanisms of aerosols associated with minor and major elements are discussed.

Lim, B.; Jickells, T. D.; Davies, T. D.

44

Microbial Volatilization of Arsenic  

Microsoft Academic Search

Arsenic is a dangerous toxin and can be volatilized by many organisms, of which bacteria is a major source. We evaluated whether three common bacteria can volatilize immobile arsenic as well as evaluated a method used for measuring volatile arsenic in fungi can be used for bacteria. Bacillus cereus, Staphlococcus aureus, and Psuedomonas aeruginosa were incubated in media containing 10ppm,

Prince Amoako; Danny Aylwin; Sean O'Connor

45

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

SciTech Connect

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.

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

2000-08-23

46

Mutations that affect ion channels change the sensitivity of Drosophila melanogaster to volatile anesthetics.  

PubMed

We have quantitated the response of D. melanogaster to general anesthetics with a device, the inebriometer, that assays the fly's geotactic and postural behavior. When alleles of several loci that encode or regulate subunits of ion channels were compared with control stocks, several ion channel mutants clearly increased the anesthetic sensitivity of Drosophila. The effects were specific in that: a) for several alleles, genetic tests indicated that the anesthesia phenotype was due to the ion channel mutation and not to extraneous genetic differences between the stocks; b) a given ion channel mutation often affected the response to one anesthetic but not another; and c) the behavior of decapitated flies in the inebriometer indicated that the anesthetic phenotype of several mutants did not merely reflect a global change in the fly's physiology. These results provide support for the idea that ion channels are on the pathway(s) influenced by anesthetics and that different anesthetics use different pathways. They also provide perspective on the behavior of previously isolated mutations (har) that decrease the sensitivity of Drosophila to anesthetics in the inebriometer. PMID:8618174

Leibovitch, B A; Campbell, D B; Krishnan, K S; Nash, H A

1995-04-01

47

ICRH of JET and LHD Majority Ions at Their Fundamental Cyclotron Frequency  

SciTech Connect

Results of the experimental studies of ICRH at the fundamental cyclotron frequency of the majority deuterons in JET plasmas with near-tangential deuteron neutral beam injection (NBI) are presented. 1D, 2D and 3D ICRH modeling indicated that several ITER relevant mechanisms of heating may occur simultaneously in this heating scheme: fundamental ion cyclotron resonance heating of majority and beam D ions, impurity ion heating and electron heating due to Landau damping and TTMP. These mechanisms were studied in JET experiments with a {approx}90% D, 5% H plasma including traces of Be and Ar. Up to 2MW of ICRH power was applied at 25 MHz to NBI heated plasmas. In most of the discharges the toroidal magnetic field strength was 3.3T, but in one it was equal to 3.6T. The E{sub +} component of the electric field governs the ion cyclotron heating of not too fast particles. The Doppler shifted RF absorption of the beam deuterons away from the cold resonance at which E{sub +} is small was exploited to enhance the RF power absorption efficiency. Fundamental ICRH experiments were also carried out in LHD hydrogen plasma with high energy hydrogen NBI. ICRH was performed at 38MHz with injected power <1 MW. The effect of fundamental ICRH was clearly demonstrated in both machines.

Krasilnikov, A. V.; Kaschuck, Yu. A.; Amosov, V. N. [SRC RF Troitsk Institute for Innovating and Fusion Research, Troitsk (Russian Federation); Van Eester, D.; Lerche, E. [Laboratory for Plasma Physics--ERM/KMS, TEC partner, Brussels (Belgium); Ongena, J.; Bonheure, G. [Laboratory for Plasma Physics--ERM/KMS, TEC partner, Brussels (Belgium); Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Mailloux, J.; Stamp, M.; Jachmich, S.; Leggate, H.; Walden, A.; Mayoral, M.-L.; Santala, M.; Kiptily, V.; Popovichev, S. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Vdovin, V. [RNC Kurchatov Institute, Nuclear Fusion Institute, Moscow (Russian Federation); Biewer, T. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Crombe, K. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Department of Applied Physics, Ghent University, Gent (Belgium); Esposito, B. [ENEA, Frascati (Italy)] (and others)

2007-09-28

48

Corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry for monitoring of volatile organic compounds.  

PubMed

We demonstrate the application of corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry (CD IMS-oaTOF) for volatile organic compounds (VOCs) monitoring. Two-dimensional (2D) IMS-oaTOF spectra of VOCs were recorded in nearly real time. The corona discharge atmospheric pressure chemical ionization (APCI) source was operated in positive mode in nitrogen and air. The CD ion source generates in air H(3)O(+)(H(2)O)(n) and NO(+). The NO(+) offers additional possibility for selective ionization and for an increase of the sensitivity of monoaromatic compounds. In addition to H(3)O(+)(H(2)O)(n) and NO(+), we have carried out ionization of VOCs using acetone as dopant gas ((CH(3))(2)COH(+)). Sixteen model VOCs (tetrahydrofuran, butanol, n-propanol, iso-propano, acetone, methanol, ethanol, toluene, benzene, amomnia, dioxan, triethylamine, acetonitrile, formaldehyde, m-xylene, 2,2,2-trifluoroethylamine) were tested using these ionization techniques. PMID:22594852

Sabo, Martin; Matej?ík, Štefan

2012-05-25

49

Rainwater Chemistry at Mt. Etna (Italy): Natural and Anthropogenic Sources of Major Ions  

Microsoft Academic Search

Major ion content of 37 wet-only rainwater samples collected on the southern flank of Mount Etna volcano was investigated. Measured pH values range from 3.80 to 7.22 and display a positive correlation with Ca2+ and an inverse correlation with NO3-, suggesting that anthropogenic NOx are the most effective acidifying agents while Ca, likely as solid CaCO3, is the prevailing proton

A. Aiuppa; P. Bonfanti; W. D'Alessandro

2003-01-01

50

Sources and cycling of major ions and nutrients in Devils Lake, North Dakota  

USGS Publications Warehouse

Devils Lake is a saline lake in a large, closed drainage basin in northeastern North Dakota. Previous studies determined that major-ion and nutrient concentrations in Devils Lake are strongly affected by microbially mediated sulfate reduction and dissolution of sulfate and carbonate minerals in the bottom sediments. These studies documented substantial spatial variability in the magnitude of calculated benthic fluxes coincident with the horizontal salinity gradient in Devils Lake. The purpose of the present study is to evaluate seasonal variability in benthic-flux rates, and to understand the effect of these fluxes on the major- chemistries in Devils Lake between May and October 1991. During the study period, the water column was well mixed, and specific conductance, pH, and temperature did not vary with depth. Dissolved oxygen was enriched near the lake surface due to photosynthesis. Major-ion concentrations and nutrient concentrations did not vary with depth. Because the water-quality data were obtained during open-water periods, the vertical profiles reflect well-mixed conditions. However, the first and last profiles for the study period did document near-bottom maxima of major cations. Secchi-disk depth varied from 0.82 meter on May 7, 1991, to 2.13 meters on June 5, 1991. The mean Secchi-disk depth during the study period was 1.24 meters. Seasonal variations in Secchi-disk depths were attributed to variations in primary productivity and phytoplankton communities. Nutrient cycles in Devils Lake were evaluated using gross primary productivity rate data, sediment trap data, and major-ion and nutrient benthic-flux rate data. Gross primary productivity rate was smallest in May (0.076 gram of carbon per square meter per day) and largest in September (1.8 grams of carbon per square meter per day). Average gross primary productivity for the study period was 0.87 gram of carbon per square meter per day. Average gross primary productivity is consistent with historic data from Devils Lake and with data from other eutrophic lakes. The average flux of organic carbon for the study period was 12 grams per square meter per day. The calculated carbon to nitrogen to phosphorus ratio (317:25:1) is similar to the Redfield ratio (106:16:1); therefore, most organic matter probably is derived from lacustrine phytoplankton. Calculated benthic-flux rates indicated that bottom sediments are important sources of majorions and nutrients to Devils Lake. Only one of the cores collected during this study indicated a net sulfate flux from the lake into the sediments. Seasonal variations in major-ion and nutrient benthic fluxes generally were small. However, there were important differences between the calculated benthic fluxes for this study and the calculated benthic fluxes for 1990. Calculated benthic fluxes of bicarbonate, ammonia, and phosphorus for this study were smaller than calculated benthic fluxes for 1990. The large differences between fluxes for 1990 and 1991 were attributed to calm, stratified water-column conditions in 1990 and well-mixed water-column conditions in 1991. The role of benthic fluxes in the chemical mass balances in Devils Lake was evaluated by calculating response times for major ions and nutrients in Devils Lake. The calculated response times for major ions in Devils Lake ranged from 6.7 years for bicarbonate to 34 years for sulfur (as S04). The response times for major ions are significantly shorter than previous estimates that did not include benthic fluxes. In addition, the relatively short response times for nitrogen (4.2 years) and phosphorus (0.95 year) indicate that nutrients are recycled rapidly between bottom sediments and the lake. During the study period, benthic fluxes were the dominant source of major ions and nutrients to Devils Lake and greatly reduced the response times of all major ions and nutrients for Devils Lake. As a result, bottom-sediment processes appear to buffer major-ion and nutrient concent

Lent, R. M.

1994-01-01

51

Detection of Volatile Vapors Emitted from Explosives with a Hand-held Ion Mobility Spectrometer  

SciTech Connect

Vapor detection of plastic explosives is difficult because of the low vapor pressures of explosive components (i.e. RDX and PETN) present in the complex elastomeric matrix. To facilitate vapor detection of plastic explosives, detection agents (taggants) with higher vapor pressures can be added to bulk explosives during manufacture. This paper investigates the detection of two of these taggants, ethyleneglycol dinitrate (EGDN) and 2,3-dimethyl-2,3-dinitrobutane (DMNB), using a handheld ion mobility spectrometer. These two taggants were detected both from neat vapor sources as well as from bulk explosives (nitroglycerin (NG)-dynamite and C-4 tagged with DMNB). EGDN was detected from NG-dynamite as EGDN·NO3- at a reduced mobility value of 1.45 cm2 V-1 s-1 with detection limits estimated to be about 10 ppbv. DMNB was identified from tagged C-4 as both negative and positive ions with reduced mobility values of 1.33 cm2 V-1 s-1 for DMNB·NO2- and 1.44 cm2 V-1s-1 for DMNB·NH4+. Positive ions for cyclohexanone were also apparent in the spectra from tagged C-4 producing three additional peaks.

Ewing, Robert Gordon; Miller, Carla Jean

2001-11-01

52

Implications for magmatic processes at Ontong Java Plateau from volatile and major element contents of Cretaceous basalt glasses  

Microsoft Academic Search

Major elements Cl, CO2, and H2O were determined in unaltered tholeiitic basalt glasses from Drilling Program Sites 803D and 807C on Ontong Java Plateau (OJP), and Sites 462A in Nauru Basin (NB) and 802A in East Mariana Basin (EMB). Glasses are moderately evolved (Mg# = 5360) with low Na2O, indicating they formed by large extents of melting. Extent of melting

Peter J. Michael

1999-01-01

53

Implications for magmatic processes at Ontong Java Plateau from volatile and major element contents of Cretaceous basalt glasses  

Microsoft Academic Search

Major elements, Cl, CO2, and H2O were determined in unaltered tholeiitic basalt glasses from Drilling Program Sites 803D and 807C on Ontong Java Plateau (OJP), and Sites 462A in Nauru Basin (NB) and 802A in East Mariana Basin (EMB). Glasses are moderately evolved (Mg# = 53-60) with low Na2O, indicating they formed by large extents of melting. Extent of melting

Peter J. Michael

1999-01-01

54

Crustal Assimilation at Mid-Ocean Ridges Using Major and Trace Elements, Volatiles, Oxygen Isotopes and Petrologic Modeling  

Microsoft Academic Search

While the majority of eruptions at spreading centers produce lavas with relatively homogeneous mid-ocean ridge basalt (MORB) compositions, the formation of tholeiitic andesites and dacites at mid-ocean ridges (MOR) remains a petrologic enigma. Andesitic and dacitic lava flows have been observed and sampled at several different locations along the global MOR system; including propagating ridge tips at ridge-transform intersections on

Dorsey Wanless; Michael Perfit; W. Ian Ridley; Emily Klein; Paul Wallace; John Valley; Craig Grimes

2010-01-01

55

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

Microsoft Academic Search

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

Leonardo Mata; Helena Gaspar; Fátima Justino; Rui Santos

56

Major ions in typical subterranean rivers and their anthropogenic impacts in southwest karst areas, China  

NASA Astrophysics Data System (ADS)

Subterranean rivers contain much of the groundwater in karst and supply many local people in southwest China. The quality of groundwater in subterranean rivers is of concern because of its sensitivity to anthropogenic activity. Groundwater samples in a rural catchment were collected at the discharge point, and the concentrations of major ions including potassium, sodium, calcium, magnesium, chloride, sulfate, nitrate and bicarbonate were analyzed in this study. Rainfall and discharge were also observed at the same time. It could be concluded from the data that the concentrations of sulfate and nitrate had a peak in the rainy season when the concentrations of sodium, calcium, magnesium and bicarbonate were low. The concentrations of potassium and chloride changed randomly throughout the year. The concentration of major ions in flood process was not completely controlled by discharge. Only the concentrations of nitrate and sulfate had obviously increased during the past two decades. It was believed that dilution, eluviation, karst erosion and anthropogenic activity can explain the ion variations and hence this study helps to understand environmental problem in karst.

Guo, Fang; Jiang, Guanghui; Yuan, Daoxian

2007-11-01

57

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

SciTech Connect

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.

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

1993-12-31

58

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

Microsoft Academic Search

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

Jurgen Engelberth; Thomas Koch; Gode Schuler; Nadine Bachmann; Jana Rechtenbach; Wilhelm Boland

2001-01-01

59

Determination of three major components of bitespiramycin and their major active metabolites in rat plasma by liquid chromatography-ion trap mass spectrometry  

Microsoft Academic Search

The rapid, selective and sensitive liquid chromatographic–ion trap mass spectrometric (LC–MSn) method was developed and validated for determination of three major components (isovaleryspiramycins, ISV-SPMs) of a novel macrolide antibiotic bitespiramycin and their major active metabolites (spiramycins, SPMs) in rat plasma. The analytes ISV-SPMs, SPMs, internal standard roxithromycin and azithromycin were extracted from plasma samples by liquid–liquid extraction, and chromatographed on

Dafang Zhong; Xiangguo Shi; Lu Sun; Xiaoyan Chen

2003-01-01

60

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

Microsoft Academic Search

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

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

1997-01-01

61

Volatile budget of Eyjafjallajokull magmas  

NASA Astrophysics Data System (ADS)

Volatile elments played a critical role in the style of activity during the 2010 eruptions of the glacier-covered Eyjafjallajokull volcano in Iceland. The alkali basalt flank eruption at Fimmvorduhals was dominated by vigorous fire fountaining that produced dominantly spatter-fed aa lava flows. Production of fine ash during the subsequent summit eruption has been variously attributed to magma fragmentation, either due to water-ice-magma interaction related to the 250 m thick glacier cover over the crater, or juvenile volatile content of the magma. Considering the great impact of the ash dispersal on trans-North Atlantic aviation, knowledge of the fragmentation mechanism and the relative roles of juvenile magmatic gases versus phreatomagmatic fragmentation is of prime significance. To evaluate the potential importance of juvenile components, the concentrations of volatiles in magmas erupted in 2010 from Eyjafjallajokull volcano in Iceland have been measured. Analysis of glass inclusions in olivine Fo 77-85 and plagioclase phenocrysts in the alkali basalt magma erupted at Fimmvorduhals flank eruption contain high total volatiles in the range 0.96 - 2.12 wt.%, and sulfur 0.10 - 0.16 wt.%. These glass inclusions are comparable to major element bulk composition of Fimmvörduháls alkali basalt lavas. In contrast, tephra from the explosive summit crater eruption are trachy-andesitic. This magma contains a rather wide range of olivine and plagioclase phenocrysts of Fo48-79 and An 69-81, with both basaltic and andesitic glass inclusions. This diversity is also reflected in a much wider range of total volatile content from 0.1 - 2.88 wt.% and sulfur 0.1 - 0.24 wt.%. At the basic end, the glass inclusions are comparable to the Fimmvorduhals alkali basalt lava, but some have andesitic composition. The highest volatile content is observed in the andesitic glass inclusions in plagioclase An78. Further analysis of glass inclusions and matrix glass by FTIR and ion probe is in progress.

Sigurdsson, H.; Mandeville, C. W.

2010-12-01

62

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

PubMed

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

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

2012-02-28

63

Determination of the volatile fraction of Polygonum bistorta L. at different growing stages and evaluation of its antimicrobial activity against two major honeybee (Apis mellifera) pathogens.  

PubMed

The composition of the volatile fraction of Polygonum bistorta L. (also known as bistort or snakeroot) was investigated. Fresh aerial parts of this plant species were collected in the Western Italian Alps during the summer at three different phenological stages, namely vegetative, flowering, and fruiting, and steam-distilled in a Clevenger-type apparatus. The oils accounted for 0.004 to 0.010% of the fresh plant material, and their compositions were determined by GC/FID and GC/MS. The composition of the oils during the vegetative period varied both in quantity and quality; several classes of compounds were found with a predominance of alcohols in the vegetative phase, terpenes and linear-chained saturated hydrocarbons in the flowering phase, while saturated aliphatic acids and their methyl esters were predominant in fruiting phase. The most abundant compounds were 3-methylbut-3-en-1-ol in the vegetative phase, linalool in the flowering phase, and dodecanoic acid and its methyl ester in the fruiting phase. The obtained essential oils were then tested against two major bee pathogens, i.e., Paenibacillus larvae and Melissococcus plutonius, and against a reference bacterial species, Bacillus subtilis. Data were compared to those obtained with reference standards used against those pathogens such as the essential oils obtained from leaves and bark of Cinnamomum zeylanicum (cinnamon), and the antibiotic oxytetracyclin. PMID:22344911

Cecotti, Roberto; Carpana, Emanuele; Falchero, Luca; Paoletti, Renato; Tava, Aldo

2012-02-01

64

Major ion chemistry and weathering processes in the Midyan Basin, northwestern Saudi Arabia.  

PubMed

Chemical characteristics of 72 groundwater samples collected from Midyan Basin have been studied to evaluate major ion chemistry together with the geochemical and weathering processes controlling the water composition. Water chemistry of the study area is mainly dominated by Na, Ca, SO4, and Cl. The molar ratios of (Ca?+?Mg)/total cations, (Na?+?K)/total cations, (Ca?+?Mg)/(Na?+?K), (Ca?+?Mg)/(HCO3?+?SO4), (Ca?+?Mg)/HCO3, and Na/Cl reveal that water chemistry of the Midyan Basin is controlled by evaporite dissolution (gypsum and/or anhydrite, and halite), silicate weathering, and minor contribution of carbonate weathering. The studied groundwater samples are largely undersaturated with respect to dolomite, gypsum, and anhydrite. These waters are capable of dissolving more of these minerals under suitable physicochemical conditions. PMID:23609922

Ghrefat, Habes A; Batayneh, Awni; Zaman, Haider; Zumlot, Taisser; Elawadi, Eslam; Nazzal, Yousef

2013-04-24

65

210Po and major ions in drainage water from soil treated with various types of fertilizers.  

PubMed

The levels of (210)Po, nutrients (NH(4)(+), NO(3)(-), PO(4)(3 -)) and major ions (Na(+), K(+), Mg(2 +), Ca(2 +), F(-), NO(2 -), Br(-), Cl(-), SO(4)(2 -)) 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 performed by using alpha -spectrometry in the case of (210)Po, or Ion Exchange liquid chromatography for the other ionic species. Statistical uni and multivariate analysis of the results shown significant differences among lixiviates according to the different fertilizer treatments. Sewage sludge and manure applications resulted in similar compositions of lixiviates with low (210)Po levels, whereas synthetic fertilizers produced higher (210)Po concentrations and different concentration patterns of ionic species when applied at or above the recommended rates. All (210)Po levels were well below the limits proposed by the 2001/928/ Euratom Recommendation. The concentrations of the rest of the ionic species, exception made from NH(4)(+) and NO(3)(-), were also below the limits proposed by Spanish regulations. PMID:17616876

Jiménez, Fernando; López, Raúl; Debán, Luis; Pardo, Rafael; García-Talavera, Marta

2007-07-01

66

Seasonal changes in the major ion and ?13CDIC geochemistry of Arctic Alaskan rivers  

NASA Astrophysics Data System (ADS)

Model predications indicate anthropogenic greenhouse warming will be most severe at high latitudes where permafrost stores large quantities of organic carbon. Permafrost thaw could reintroduce this carbon into the carbon cycle and transform the Arctic into a source of CO2 and possibly, CH4. Thus, tracking the rate and extent of permafrost thaw bears on understanding feedbacks between Arctic climate change and global warming. Downward movement of the seasonally thawed “active” layer into previously frozen soils may yield unique mineral weathering signatures that relate to changes in carbon storage. We present two potential tracking methods, namely seasonal changes in dissolved major ion concentrations and the carbon isotope composition of dissolved inorganic carbon (?13CDIC). We also present a novel method for measuring carbonate alkalinity in organic-rich rivers. Water samples were collected from six watersheds on the North Slope of Alaska. All rivers drain continuous permafrost but three drain tussock tundra-dominated watersheds and three drain bare bedrock catchments with minor tundra influences. Water samples were collected from April until October in 2009 and 2010. In organic-rich rivers, carbonate alkalinity and alkalinity associated with dissolved organic matter may contribute to total alkalinity. Carbonate alkalinity is difficult to measure at the low pH conditions common in organic-rich rivers. Moreover, conventional methods for measuring alkalinity, such as Gran titration, tend to overestimate total alkalinity, presumably because organic matter absorbs more protons than its functional charge equivalent. Thus, we measured dissolved CO2 in-situ using a customized NDIR sensor, and we calculated carbonate alkalinity using carbonate equilibria equations. Initial results suggest this method accurately characterizes the carbonate geochemistry of organic-rich rivers. Major ion and ?13CDIC trends suggest that silicate weathering dominates during the spring melt while carbonate weathering dominates as the summer progresses and the active layer deepens. In tundra streams, early season ?13CDIC values indicate carbonic acid-silicate weathering. Late season ?13CDIC values indicate carbonic acid-carbonate weathering. In both cases, the microbial decomposition of C3 organic matter provides the dissolved CO2 that forms carbonic acid. Bedrock streams display high and nearly constant ?13CDIC values from spring melt to fall base flow. These streams also have high dissolved sulfate concentrations. The ?13CDIC values may originate from sulfuric acid-carbonate weathering, although isotopic equilibration with atmospheric CO2 could be important. The difference between the tundra versus bedrock streams isolates the geochemical signature of active layer weathering processes. Our study indicates how seasonal changes in mineral weathering can track deepening of the active layer.

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

2010-12-01

67

Seasonal Variability of Major Ions and ?13CDIC in Permafrost Watersheds of Arctic Alaska  

NASA Astrophysics Data System (ADS)

Models and observations predict that climate change will have more severe effects at higher latitudes. Many effects may already be underway. Increasing temperatures are expected to thaw permafrost soils, changing the hydrology and biogeochemistry of Arctic watersheds. These changes are particularly important because permafrost thaw could destabilize a large carbon reservoir, potentially leading to sizable greenhouse gas emissions. Tracking soil thaw and concomitant changes in carbon export are therefore critical to predicting feedbacks between Arctic climate change and global warming. As the climate warms, the seasonally thawed active layer will extend into deeper, previously frozen, mineral-rich soils, increasing the signal of chemical weathering in streams. Historical methods of monitoring active layer thaw depth are labor intensive and may not capture the heterogeneity of Arctic soils, whereas stream geochemistry provides a unique opportunity to integrate signals across vast spatial distances. We present major ion geochemistry and ?13C of dissolved inorganic carbon (DIC) variations that relate to seasonal changes in permafrost thaw depths. Samples were collected from six watersheds on the North Slope of Alaska. All rivers drain continuous permafrost but three drain tussock tundra-dominated watersheds and three drain bare bedrock catchments with minor tundra influences. Water samples were collected from April until October in 2009 and 2010. The major ion and ?13CDIC trends of tundra streams suggest that silicate weathering dominates during the spring melt while carbonate weathering dominates as the active layer deepens in the summer. In tundra streams, early season ?13CDIC values indicate carbonic acid-silicate weathering. Summer ?13CDIC values indicate carbonic acid-carbonate weathering. In both cases, carbonic acid forms from CO2 produced by the microbial decomposition of C3 organic matter. Bedrock streams have nearly constant ?13CDIC values and high dissolved sulfate concentrations through the year, indicating sulfuric acid-carbonate weathering. In late fall of 2010, ?13CDIC decreases in all streams suggest increased CO2 from a source with relatively negative ?13C values, possibly methane oxidation in soils. The difference between the tundra and bedrock streams allows us to clearly isolate the effect of soil thaw on stream geochemistry. Our initial findings illustrate how seasonal changes in mineral weathering have potential for tracking active layer dynamics.

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

2011-12-01

68

Ion channel-forming alamethicin is a potent elicitor of volatile biosynthesis and tendril coiling. Cross talk between jasmonate and salicylate signaling in lima bean.  

PubMed

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 A(2) do not prevent the coiling reaction. PMID:11154344

Engelberth, J; Koch, T; Schüler, G; Bachmann, N; Rechtenbach, J; Boland, W

2001-01-01

69

Seasonal and Annual Fluxes of Nutrients and Major Ions from Large Rivers to the Arctic Ocean  

NASA Astrophysics Data System (ADS)

Warming air temperatures are impacting most aspects of the Arctic system. One challenge faced by scientists and funders alike is how to efficiently obtain the observations that are needed to understand the changing Arctic. This challenge is perhaps particularly acute in terrestrial systems where spatial heterogeneity is often great, requiring an extensive network of sites in order to adequately document conditions. Rivers provide one means of investigating terrestrial change over large spatial domains: by monitoring river discharge and chemistry at a single downstream station, it is possible to make inferences about changes occurring throughout their watersheds. Here we provide improved estimates of biogeochemical fluxes from the six largest Arctic rivers (Yenisey, Lena, Ob’, Mackenzie, Yukon, Kolyma), which have a combined watershed area of ~11 million square kilometers. River biogeochemistry data are obtained from the NSF-supported PARTNERS and Student-Partners projects. In order to estimate annual fluxes, the USGS’s Loadest program was used to model chemical concentrations and fluxes on days when samples were not collected. Specifically, we investigate seasonal and annual fluxes of nutrients (NO3, NH3, DON, TDP, Si) and major ions (Cl, SO4, Na, K, Mg, Ca) over a 10-year period (1998-2008). These new estimates provide the contemporary baseline against which to judge future changes.

Holmes, R. M.; McClelland, J. W.; Tank, S. E.; Bulygina, E. B.; Thomas, S.; Peterson, B. J.

2009-12-01

70

Wet precipitation of major ions, polonium-210, and organic carbon in a metropolitan city, Seoul, Korea  

NASA Astrophysics Data System (ADS)

An extensive survey of chemical constituents in precipitation including dissolved organic carbon, dissolved nitrogen, major ions, trace elements, and radionuclides was conducted in a representative urban environment of Seoul over one-year period from 2009 to 2010. The sources for these chemical species were apportioned by applying principal component analysis (PCA) in association with commonly acknowledged key tracers, such as Na, K, Ca, and V. The fossil fuel combustion (especially coal) was shown to be the dominant source for most constituents being investigated, with biomass burning being recognized as another significant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of the chemical species in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from the eastern and northeastern China might contribute substantially. Overall, our study suggests the significant role of human activities in altering the atmospheric environment of Seoul and presumably most urban areas around the world, highlighting its profound environmental implications, such as health risks posed by excessive polonium-210, enhanced rainwater acidity from organic acids, and radiative forcing by organic aerosols.

Yan, G.; Kim, G.

2011-12-01

71

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

PubMed

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

Gardner, Christopher B; Carey, Anne E

2004-10-15

72

Major and Trace Elements and Volatiles in Glasses from the 2009 Rapid Response Expedition to West Mata Volcano and Northeast Lau Spreading Center (NELSC)  

NASA Astrophysics Data System (ADS)

The expedition to W. Mata volcano and NELSC in May, 2009 recovered samples from very young or ongoing eruptions, as well as older nearby eruptives from both volcanic centers. Mg#s of glasses range from 58-61 for the newest eruption at W. Mata, to 49 for older eruptives. Glasses from NELSC vary from Mg#=53-64. Based on the Si6-Ti6 discriminant used to estimate magmatic heritage [1], we infer that glasses from W. Mata are derived from a boninitic primary melt, whereas those at NELSC had basaltic primary magmas. Low H2O and S contents suggest that volatiles were mostly lost by degassing from all samples. Incompatible element and volatile contents are influenced by both a subduction-related component and an enriched OIB component that might be related to the Samoan plume or to subducting seamounts. Cl/K=0.20-0.31 for all samples, similar to other boninites from Tofua arc [1] and basalts from NELSC [2] and higher than MORB and OIB (Cl/K<0.06), reflecting the influence of subducted material. High La and very high Nb in both volcanoes reflect additional OIB-like inputs as well. For youngest glasses from W. Mata, there is significant scatter in plots of major and incompatible elements versus Mg#. A group of glasses define a liquid line of descent (LLD) consistent with 8% crystallization of 80% CPX +10% olivine (Fo85)+10%OPX: quite different from observed proportions in which OPX is dominant. Other young glasses either had different primary magmas or evolved with different phase proportions, due to different pressure or H2O during crystallization. Melt inclusions in Fo85 olivine are more primitive and diverse than host glasses. A few have much lower K and Ti. Most have low inferred H2O and S contents, suggesting they degassed slightly less than the host glass during shallow entrapment. Older samples from W. Mata from further down the rift are more fractionated and have much higher K and K/Ti, requiring a different primary magma composition. NELSC glasses have higher Na, Ti and Al and lower SiO2 than W. Mata glasses. Despite the small area of collection, it is not possible to relate any glass to any other glass by fractional crystallization alone: K, Ti and incompatible elements are too variable. At least four different lineages are necessary. Glasses from the very young PuiPui eruption are highly enriched in P, F, and LREE and contain up to 36 ppm Nb: approaching Samoa and other OIB in concentration. Yet not even the glasses of this single eruption can be related to each other by crystallization: the most primitive glasses have the highest incompatible element content. The range of compositions is consistent with the diversity of compositions along this part of the axis [2]. Some of the complexity might have resulted from mixing of diverse magmas: an OIB-like liquid and a liquid that was influenced more by subduction. [1] Cooper et al. (in revision). [2] Escrig et al., (this meeting; in preparation).

Michael, P. J.; Escrig, S.; Rubin, K. H.; Cooper, L. B.; Langmuir, C. H.; Clague, D. A.; Keller, N. S.; Plank, T.

2009-12-01

73

Major Ion Chemistry in a Freshwater Coastal Lagoon from Southern Brazil (Mangueira Lagoon): Influence of Groundwater Inputs  

Microsoft Academic Search

This paper characterizes major ion distributions and investigates whether groundwater exerts a major control on the chemical\\u000a functioning of Mangueira Lagoon, a large (90 km long), shallow (?4–5 m deep), and fresh coastal lagoon in southern Brazil.\\u000a Water volumes equivalent to ?80% of the total annual input are used in the summer for irrigating nearby rice plantations,\\u000a the most important regional economic

Isaac R. Santos; Maria I. Machado; Luis F. Niencheski; William Burnett; Idel B. Milani; Carlos F. F. Andrade; Richard N. Peterson; Jeffrey Chanton; Paulo Baisch

2008-01-01

74

The general description of major ion concentrations in groundwater of Latvia  

NASA Astrophysics Data System (ADS)

Latvia is situated at the North central part of the Baltic sedimentary basin where the crystalline basement is found in depth between 0.6 to 2 km. Three large aquifer complexes with distinct chemical composition of groundwater are identified: the stagnant water exchange zone where Na-Ca-Cl brine is found; the slow water exchange zone where Na-Ca-Cl-SO4 brackish water is found and active water exchange zone where the freshwater resides. These are separated by distinct regional aquicludes. The composition of the Cl- dominated brines at the base of sedimentary basin is characterised by shift from Na+ towards Ca++ as dominant cation, partially associated with depth of the aquifer and the strength of the brine. The concentration of SO4-- here is inversely linked to the concentration of Ca++ and, according to geochemical modelling, often is close to the solubility limit of the gypsum. The major ion concentrations in the E and W part of the territory are rather different. Therefore two different initial sources of the formation brine were suggested. Alternatively the observations can be explained by different thermal histories of different parts of the basin, affecting the rate of albitization - exchange of the Na for Ca in the solution due to water-rock interaction. The groundwater composition in the slow exchange zone can be nicely explained by the mixing of freshwater and brine residing deeper in the presence of gypsum during some but no all stages of mixing. In some shallow parts of the zone still bound by the Narva regional aquiclude freshwater is found. The question is posted - could this be a paleogroundwater originating from the extensive continental glaciations that override the territory several times during the Pleistocene? Initial isotope studies presented elsewhere seems to give negative answer to this question. The active water exchange zone is characterised by fresh Ca-Mg-HCO3 water with exceptions in cases where gypsum are abundant in sedimentary rocks and sulphate ion prevails. The freshwater composition seems to be mostly controlled by three minerals - calcite, dolomite and gypsum. It is suggested that clay minerals can play a significant role in controlling the relative concentrations of cations, but this is not strictly proven jet. Well documented modern seawater intrusion induced by water abstraction is found in the territory of Liep?ja city. The upwelling of slat water from below can be spotted across the territory as well. These zones are usually associated with tectonic faults, enabling the upwelling of salty water across regional aquicludes. Particularly prominent is the saltwater body in the vicinity of the Riga city. Three major rives are discharging in the sea there making it a natural confluence zone of groundwater as well. The intensive groundwater abstraction in the city probably enhanced the upwelling of saltwater here, but primary it is a natural phenomenon. The interesting question is if there is any paleogroundwater trapped in the active or slow water exchange zone of the sedimentary basin that could be distinguished from modern infiltration water due to particular isotope signal originating in the quaternary cold stages or chemical composition - remains of relict sea water or sedimentation water. This study is supported by the ESF project No. 2009/0212/1DP/1.1.1.2.0/09/APIA/VIAA/060.

Kalv?ns, A.; Delina, A.

2012-04-01

75

The wet deposition of acid and some major ions over the Japanese Archipelago  

NASA Astrophysics Data System (ADS)

The wet deposition of acid and some major ions over the Japanese Archipelago was presented. The country was divided into 15 climatic regions with 114 grid squares, and the annual and seasonal fluxes of non-sea salt sulfate, nitrate, ammonium and non-sea salt calcium were estimated. Wet deposition fluxes were determined from CRIEPI's regional monitoring data at 21 sites between October 1987 and September 1990. The concentration of these ions in precipitation increased during the cold season, and this tendency was noted on the northwestern region facing the continent across the Japan Sea. Estimated wet deposition of [nss-SO42-]+[NO3-], here defined as the acidic component (AC), was approximately 75 meq m-2 yr-1, and that for [NH4+]+[nss-Ca2+], here defined as the basic component (BC), was approximately 52 meq m-2 yr-1. If the concentration difference of AC - BC was converted to the wet deposition of H+, it was approximately 23 meq m-2 yr-1, or the total deposition over the Japanese Archipelago was approximately 17 Geq yr-1. For Japan as a whole, wet deposition of inferred H+ in the warm season and the cold season accounted for 45% and 55%, respectively. In the warm season, the major receptor of acid was the climate regions facing the Pacific Ocean, while in the cold season it was the climate regions facing the Japan Sea. The wet deposition over the Japanese Archipelago was influenced by two factors: meteorological conditions such as the wind system and rainfall pattern due to Asian monsoons, and the geographical distribution of emission sources of chemical substances through natural and anthropogenic activities in East Asia. It was suggested that in-flow of chemical substances from outside the region plays an important role in the wet deposition field over the Japanese Archipelago.

Fujita, Shin-Ichi; Takahashi, Akira; Sakurai, Tatsuya

2003-02-01

76

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

Microsoft Academic Search

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

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

2000-01-01

77

Riverine inputs of major ions and trace elements to the tidal reaches of the River Tweed, UK.  

PubMed

This paper examines spatial and temporal variability in freshwater inputs of trace elements and major ions to the tidal reaches of the River Tweed. The relationships between concentrations of major ions and trace elements (in dissolved and acid-available particulate forms) and flow are examined, and a simple two-component endmember mixing analysis performed to link river water chemistry to catchment sources, and to identify whether within-river processes modify concentrations to produce non-conservative behaviour. The results indicate that most dissolved major ions and trace elements behave conservatively in the lower reaches of the River Tweed, the variability in concentrations being dominated by hydrology and the existence of different high-flow and low-flow endmember runoff chemistries. This suggests that the variability in concentration of most dissolved trace elements and major ions in the lower Tweed can be modelled using simple mixing relationships. However, the relationships between pH, Ca, Mg and Gran alkalinity show pronounced non-conservative behaviour, indicating the importance of understanding within-river process for modelling these determinants. The non-conservative behaviour identified is related to biological controls and the resultant diurnal variations in pH which promote daytime removal of Ca from solution by precipitation of calcium carbonate (and corresponding removal of Mg by co-precipitation) during extreme low-flow conditions and algal blooms during the summer. PMID:10847153

Jarvie, H P; Neal, C; Tappin, A D; Burton, J D; Hill, L; Neal, M; Harrow, M; Hopkins, R; Watts, C; Wickham, H

2000-05-01

78

Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal  

Microsoft Academic Search

The Ganga-Brahmaputra, one of the world's largest river systems, is first in terms of sediment transport and fourth in terms of water discharge. A detailed and systematic study of the major ion chemistry of these rivers and their tributaries, as well as the clay mineral composition of the bed sediments has been conducted. The chemistry of the highland rivers (upper

M. M. Sarin; S. Krishnaswami; K. Dilli; B. L. K. Somayajulu; W. S. Moore

1989-01-01

79

Major ion and isotope geochemistry of fluids and gases from coalbed methane and shallow groundwater wells in Alberta, Canada  

Microsoft Academic Search

The production of coalbed methane (CBM) represents a vital new source of natural gas supply in Western Canada. There are, however, concerns over potential negative environmental impacts on shallow groundwater resources in the hypothetical case that leakage of fluids and gases from CBM operations occurs. This paper compares major ion and isotope geochemistry data for produced fluids or gases from

Katrina Cheung; Patrick Klassen; Bernhard Mayer; Fariborz Goodarzi; Ramon Aravena

2010-01-01

80

Predicting Soil and Water Chemistry in and below the Root Zone of Agricultural Lands: Major Ions, Nutrients and Toxic Ions  

Microsoft Academic Search

The focus of ARS research on inorganic chemicals centers around the need to maintain a pro- ductive soil environment for crop production while minimizing or avoiding off-site degrada- tion of soil and water resources. The inorganic chemicals of interest are salts, nutrients and potentially toxic ions. Modeling is necessary for predict of the leaching of chemicals under existing practices and

D. L. Suarez

81

Determination of three major components of bitespiramycin and their major active metabolites in rat plasma by liquid chromatography-ion trap mass spectrometry.  

PubMed

The rapid, selective and sensitive liquid chromatographic-ion trap mass spectrometric (LC-MS(n)) method was developed and validated for determination of three major components (isovaleryspiramycins, ISV-SPMs) of a novel macrolide antibiotic bitespiramycin and their major active metabolites (spiramycins, SPMs) in rat plasma. The analytes ISV-SPMs, SPMs, internal standard roxithromycin and azithromycin were extracted from plasma samples by liquid-liquid extraction, and chromatographed on a C(18) column using two mobile phase systems. Detection was carried out on an ion trap mass spectrometer by selected reaction monitoring (SRM) mode via electrospray ionization (ESI). Three components (ISV-SPM I, II, III or SPM I, II, III) could be simultaneously determined within 6.5 min. Linear calibration curves were obtained in the concentration ranges of 4-200 ng/ml for ISV-SPM I and SPM I, 12-600 ng/ml for ISV-SPM II and SPM II, and 18-900 ng/ml for ISV-SPM III and SPM III. The intra- and inter-run precision (RSD), calculated from quality control (QC) samples were less than 8.8 and 10.4% for ISV-SPMs, and 9.3 and 11.2% for SPMs, respectively. The method was applied for the evaluation of the pharmacokinetics of bitespiramycin in rats following peroral/intravenous administration. PMID:12798164

Zhong, Dafang; Shi, Xiangguo; Sun, Lu; Chen, Xiaoyan

2003-07-01

82

Water chemistry in Kuji river. Its spatial and seasonal variations in major ions and organic substances.  

National Technical Information Service (NTIS)

As a basic research with a aim to clarify the migration behavior of radionuclides in rivers, the characteristics of dissolved ions and organic substances in river water, which characteristics may affect the behavior, were investigated. The investigation w...

T. Niina T. Matsunaga H. Amano

1996-01-01

83

Fully automated micro- and nanoscale one- or two-dimensional high-performance liquid chromatography system for liquid chromatography–mass spectrometry compatible with non-volatile salts for ion exchange chromatography  

Microsoft Academic Search

A one- or two-dimensional high performance liquid chromatography system for electrospray ionization mass spectrometers has been developed that is optimized for ion exchange and reversed phase separations. A unique and simple valve configuration permits the use of a variety of non-volatile salts; ammonium sulfate was used in an example of strong cation exchange separations. The system was designed and evaluated

Junichi Masuda; Dawn M. Maynard; Masayuki Nishimura; Teruhisa Ueda; Jeffrey A. Kowalak; Sanford P. Markey

2005-01-01

84

Major ion chemistry, weathering processes and water quality assessment in upper catchment of Damodar River basin, India  

Microsoft Academic Search

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were\\u000a studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water\\u000a for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected\\u000a and analysed for pH, EC, TDS, F, Cl,

Abhay Kumar Singh; G. C. Mondal; Suresh Kumar; T. B. Singh; B. K. Tewary; A. Sinha

2008-01-01

85

Discrimination of swiss cheese from 5 different factories by high impact volatile organic compound profiles determined by odor activity value using selected ion flow tube mass spectrometry and odor threshold.  

PubMed

Swiss cheese contains more than 200 volatile organic compounds (VOCs). Gas chromatography-mass spectrometry has been utilized for the analysis of volatile compounds in food products; however, it is not sensitive enough to measure VOCs directly in the headspace of a food at low concentrations. Selected ion flow tube mass spectrometry (SIFT-MS) provides a basis for determining the concentrations of VOCs in the head space of the sample in real time at low concentration levels of parts per billion/trillion by volume. Of the Swiss cheese VOCs, relatively few have a major impact on flavor quality. VOCs with odor activity values (OAVs) (concentration/odor threshold) greater than one are considered high-impact flavor compounds. The objective of this study was to utilize SIFT-MS concentrations in conjunction with odor threshold values to determine OAVs thereby identifying high-impact VOCs to use for differentiating Swiss cheese from five factories and identify the factory variability. Seventeen high-impact VOCs were identified for Swiss cheese based on an OAV greater than one in at least 1 of the 5 Swiss cheese factories. Of these, 2,3-butanedione was the only compound with significantly different OAVs in all factories; however, cheese from any pair of factories had multiple statistically different compounds based on OAV. Principal component analysis using soft independent modeling of class analogy statistical differentiation plots, with all of the OAVs, showed differentiation between the 5 factories. Overall, Swiss cheese from different factories was determined to have different OAV profiles utilizing SIFT-MS to determine OAVs of high impact compounds. PMID:24106758

Taylor, Kaitlyn; Wick, Cheryl; Castada, Hardy; Kent, Kyle; Harper, W James

2013-10-01

86

Occurrence, Distribution, and Trends of Volatile Organic Compounds in the Ohio River and its Major Tributaries, 1987-96. National Water-Quality Assessment (NAWQA) Program, National Systhesis on Volatile Organic Compounds (VOCs).  

National Technical Information Service (NTIS)

The report presents an analysis of the occurrence, distribution, and trends of VOCs in the Ohio River and its major tributaries from 1987 through 1996. Specific objectives of this analysis were to: (1) summarize VOC detections and concentrations; (2) dete...

R. F. Lungren T. J. Lopes

1999-01-01

87

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

SciTech Connect

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.

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

88

Major ion chemistry and weathering control in a high altitude basin: Alaknanda River, Garhwal Himalaya, India  

Microsoft Academic Search

An analytical study of major cations and anions of the glacier fed Alaknanda River and its tributaries has been carried out to assess the weathering and geochemical processes in the high altitude river basin. The Alaknanda and its tributaries were sampled during pre-monsoon (June 1992) and post-monsoon (October 1992) season for the present hydrogeochemical study. Calcium and magnesium are the

ABHAY KUMAR SINGH; SYED I. HASNAIN

1999-01-01

89

Major ion chemistry and weathering control in a high altitude basin: Alaknanda River, Garhwal Himalaya, India  

Microsoft Academic Search

An analytical study of major cations and anions of the glacier fed Alaknanda River and its tributaries has been carried out to assess the weathering and geochemical processes in the high altitude river basin. The Alaknanda and its tributaries were sampled during pre-monsoon (June 1992) and post-monsoon (October 1992) season for the present hydrogeochemical study. Calcium and magnesium are the

ABHAY KUMAR SINGH; SYED I. HASNAIN

1998-01-01

90

Tropical Greenhouse Measurements of Volatile Organic Compounds Using Switchable Reagent Ion Proton-Transfer-Reaction Time-of-Flight Mass Spectromety (PTR-TOF-MS)  

NASA Astrophysics Data System (ADS)

In this presentation, we will summarize the results of measurements made in an approximately 1300 m3 tropical greenhouse at the Johannes Gutenberg University botanical garden in Mainz Germany conducted over a one month period. The greenhouse is home to a large variety of plant species from hot and humid regions of the world. The greenhouse is also host to several crops such as Cocoa and Cola Nut as well as ornamental plants. A particular focus of the species maintained are those which are considered ant plants, or plants which have an intimate relationship with ants in tropical habitats. Volatile organic compounds (VOCs) were measured using a Switchable Reagent Ion Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS) using H3O+, NO+, and O2+ ion chemistry. Measurements will be presented both for primary emissions observed in the closed greenhouse atmosphere as well as the oxidation products observed after the introduction of ambient ozone. The high resolving power (5000 m/?m) of the time-of-flight instrument allows for the separation of isobaric species. In particular, both isoprene (68.1170 amu) and furan (68.0740 amu) were observed and separated as primary emissions during this study. The significance of this will be discussed in terms of both atmospheric implications as well as with respect to previous measurements of isoprene obtained using quadrupole PTR-MS where isobaric separation of these compounds is not possible. Additionally observed species (e.g. Methanol, Acetaldehyde, MVK and MEK) will be discussed in detail with respect to their behavior as a function of light, temperature and relative humidity. The overall instrument performance of the PTR-TOF-MS technique using the H3O+, NO+, and O2+ primary ions for the measurement of VOCs will be evaluated.

Veres, P.; Auld, J.; Williams, J.

2012-04-01

91

Highly treated mine waters may require major ion addition before environmental release.  

PubMed

Mining operations often use passive and/or active water treatments to improve water quality prior to environmental release. Key considerations in choosing a treatment process include the extent to which the water quality is actually improved, and the potential residual environmental risks of the release of such water. However, there are few published studies concerning the environmental impacts of treated waste waters. This study used toxicity identification evaluation (TIE) methods to quantify and identify the "toxic" constituents of a highly-treated water (distillate) produced by brine concentration of a mining process water. Exposure of five freshwater species (Chlorella sp., Lemna aequinoctialis, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) to a concentration range of the distillate (0, 25, 50 and 100%) found that it was toxic to H. viridissima (50-100% effect when exposed to 100% distillate). TIE tests demonstrated that the effect wasn't due to residual ammonia (~1 mg L(-1)N) or trace organics, and unlikely to be due to manganese (Mn; 130-230 ?g L(-1)). Conversely, addition of 0.2 and 0.5 mg L(-1) calcium improved the growth rate of H. viridissima by 61 and 66%, respectively, while addition of calcium, sodium and potassium (0.5, 1.0 and 0.4 mg L(-1), respectively) to levels comparable to that in the local aquatic environment resulted in 100% recovery. Further assessment on the likelihood of residual metal toxicity indicated that Mn concentrations in the distillate were at levels that could inhibit the growth of H. viridissima. Ultimately, the results demonstrated that ion deficiency should be considered as a potential stressor in risk/impact assessments of the discharge of treated wastewaters, and these may need to be supplemented with the deficient ions to reduce environmental impacts. The findings have highlighted the need for water managers to consider the possibility of unintended environmental risks from the discharge of highly-treated wastewaters. PMID:23183225

Harford, Andrew J; Jones, David R; van Dam, Rick A

2012-11-23

92

Wet deposition of major ions in a rural area impacted by biomass burning emissions  

NASA Astrophysics Data System (ADS)

This work concerns the influence of industrialized agriculture in the tropics on precipitation chemistry. A total of 264 rain events were sampled using a wet-only collector in central São Paulo State, Brazil, between January 2003 and July 2007. Electroneutrality balance calculations (considering H +, K +, Na +, NH4+, Ca 2+, Mg 2+, Cl -, NO3-, SO42-, F -, PO43-, H 3CCOO -, HCOO -, CO42- and HCO3-) showed that there was an excess of cations (˜15%), which was attributed to the presence of unmeasured organic anion species originating from biomass burning and biogenic emissions. On average, the three ions NH4+, NO 3- and H + were responsible for >55% of the total ion concentrations in the rainwater samples. Concentrations (except of H +) were significantly higher ( t-test; P = 0.05), by between two to six-fold depending on species, during the winter sugar cane harvest period, due to the practice of pre-harvest burning of the crop. Principal component analysis showed that three components could explain 88% of the variance for measurements made throughout the year: PC1 (52%, biomass burning and soil dust resuspension); PC2 (26%, secondary aerosols); PC3 (10%, road transport emissions). Differences between harvest and non-harvest periods appeared to be mainly due to an increased relative importance of road transport/industrial emissions during the summer (non-harvest) period. The volume-weighted mean (VWM) concentrations of ammonium (23.4 ?mol L -1) and nitrate (17.5 ?mol L -1) in rainwater samples collected during the harvest period were similar to those found in rainwater from São Paulo city, which emphasizes the importance of including rural agro-industrial emissions in regional-scale atmospheric chemistry and transport models. Since there was evidence of a biomass burning source throughout the year, it appears that rainwater composition will continue to be affected by vegetation fires, even after sugar cane burning is phased out as envisaged by recent São Paulo State legislation.

Coelho, Cidelmara H.; Allen, Andrew G.; Fornaro, Adalgiza; Orlando, Eduardo A.; Grigoletto, Tahuana L. B.; Campos, M. Lucia A. M.

2011-09-01

93

Groundwater quality in Scotland: major ion chemistry of the key groundwater bodies.  

PubMed

Groundwater in Scotland is, for the most part, weakly to moderately mineralised and dominated by the Ca and HCO3 ions. The aquifer systems are almost entirely unconfined and most groundwater remains in contact with oxygen; some reducing groundwaters occur in deeper isolated cracks and joints within the many fractured bedrock aquifers such as Devonian sandstones. Groundwater depleted in oxygen is also common in the Coal Measures in the Midland Valley as a direct result of past coal and oil shale mining, when iron and other metals are taken into solution as the abandoned mine workings are allowed to flood. Low pH groundwaters are rare but do occur where calcite is absent in some basement rocks. Marine intrusion of coastal aquifers occurs locally in East Lothian and parts of Morayshire. Deeper circulating groundwaters are responsible for some of the more exotic spa waters, notably at Bridge of Earn near Perth. Nitrate contamination of groundwater is increasing in some areas, and is most prevalent in the south of Scotland. The Devonian aquifer in Fife and parts of the Permian sandstone aquifers of south-west Scotland are the worst affected. PMID:12169011

Robins, N S

2002-07-22

94

Catechol is the major product of salicylate hydroxylation in 1-methyl-4-phenylpyridinium ion treated rats.  

PubMed

Salicylate hydroxylation using hydroxyl free radicals results into formation of 2,3-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid and catechol. Inspite of the fact that in vitro experiments have shown that catechol is a minor product, we have shown by these in vivo studies that it is a substantial product. Since catechol as well as 2,3-dihydroxybenzoic acid have not been found to be produced enzymatically from salicylates, they appear useful as in vivo indicators for monitoring hydroxyl free radicals. Administration of 1-methyl-4-phenylpyridinium ion (MPP+) to rat striatum using microdialysis results into the formation of hydroxyl radicals. Salicylate perfusion enables the estimation of the three derivatives cited above. They increased significantly after MPP+ administration in comparison to the baseline values, with catechol being the most significant. The maximum amounts were achieved 60 min after MPP+ administration, and the mean percentage increase at this time point were 83.1% for 2,3-DBA (n = 6, P = 0.005), 81.25% for 2,5-DBA (n = 6, P = 0.011) and 1228.8% for catechol (n = 4, p = 0.00008). MPP+ caused substantial decrease of dopamine metabolites. Dihydroxyphenylacetic acid decreased to 13% and homovanillic acid to 11.4%. We conclude that catechol is an important indicator of hydroxyl free radical formation in this animal model which is well suited to study the role of free radicals in Parkinsonism. PMID:9725471

Sam, E; Sarre, S; Michotte, Y; Verbeke, N

95

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

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.

Levinthal, Mark; Schiff, Jerome A.

1968-01-01

96

Application of ion-implantation for improved non-volatile resistive random access memory (ReRAM)  

NASA Astrophysics Data System (ADS)

Resistive switching in transition metal oxides is believed to be controlled by the migration of oxygen vacancies and many interesting device structures employ substoichiometric oxide layers as a source of these active defects. However, the growth of thin (˜10 nm) oxide/suboxide heterostructures (e.g. HfO2/HfOx or Ta2O5/TaOx) is difficult using conventional film deposition techniques. In this study, ion-implantation is shown to provide an alternative means of synthesizing such structures, with results reported for Ta2O5/TaOx heterostructures fabricated by oxygen-implantation of Ta. The electrical properties of the fabricated heterostructures are discussed with reference to the physical structure of the samples determined from transmission electron microscopy and X-ray photoelectron spectroscopy.

Elliman, R. G.; Saleh, M. S.; Kim, T.-H.; Venkatachalam, D. K.; Belay, K.; Ruffell, S.; Kurunczi, P.; England, J.

2013-07-01

97

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

SciTech Connect

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.

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

1981-01-01

98

Chemical characteristics of aerosols at coastal station in Hong Kong. I. Seasonal variation of major ions, halogens and mineral dusts between 1995 and 1996  

Microsoft Academic Search

Aerosols samples (total suspended particulate “TSP” and PM10 particulate) were collected at coastal monitoring station in Hong Kong between 1995 and 1996. They were analyzed to investigate the seasonal cycle among major ions (Na+, NH4+–N, K+, Mg2+, Ca2+, Cl?, NO3?, and SO42?), halogen elements (Br, I) and mineral dusts. The concentration of major ions showed a summer minimum and a

Z. L. Cheng; K. S. Lam; L. Y. Chan; T. Wang; K. K. Cheng

2000-01-01

99

Landscape controls on dissolved nutrients, organic matter and major ions in a suburbanizing watershed  

NASA Astrophysics Data System (ADS)

Understanding the relative importance of anthropogenic and natural landscape features that drive spatial variability in water quality is a central challenge in studying the biogeochemistry of heterogeneous landscapes. We quantified the average annual flux and concentration of dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON), dissolved organic carbon (DOC), phosphate-P (PO4-P), sodium (Na+) and chloride (Cl-) at ~40 stream sites in three major (51 to 903 km2) NH basins. We used GIS to quantify anthropogenic (e.g. human population density, % impervious surface cover and % agriculture) and natural (e.g. % forest, % wetlands and soil C:N) landscape features for each sub-basin and then employed multiple-regression analysis to relate water quality parameters to landscape characteristics. Anthropogenic features were strong predictors of DIN flux and Na+ and Cl- concentrations, whereas wetland cover (a natural feature) was a significant, but weak predictor of DOC (r2=0.26, p<0.01) and DON (r2 = 0.14, p<0.05) flux. Anthropogenic features could not explain a significant amount of variance in DON or DOC flux. Mean PO4-P concentrations were surprisingly low (<0.015 mg P/L) when compared to the larger range in mean DIN concentrations (0.03 to 0.96 mg/L) and consequently no landscape characteristics could explain a significant amount of spatial variability in PO4-P flux or concentration. Human population density was the single best predictor of DIN flux (r2=0.76, p<0.01), and together with % impervious surface and % agriculture explained 86% (p<0.01) of the total variance. Among all sites, % road pavement was a strong predictor of stream Na+ and Cl- concentrations (r2 = 0.75 to 0.78, p<0.01) and % impervious surface was a stronger predictor (r2 = 0.86 to 0.92, p<0.01) among a subset of sites. Our results suggest that DIN and DON result from different sources in the landscape and although sources of DON and DOC are similar, DON and DOC concentrations respond differently to hydrologic events. Concentrations of DON were negatively correlated with discharge (r2= 0.06, p < 0.01), but DOC concentrations did not respond to discharge, suggesting there is much to learn about the decoupling of C and N rich dissolved organic matter (DOM). Our landscape models do not account for spatial variability in dissolved inorganic carbon (DIC), dissolved organic P (DOP) or particulate C, N and P; however, at our site with the longest record, the Lamprey River, DIC and particulate C account for only 25% and 5% respectively of the total C flux. Among three sites ranging from 3-16% development, particulate N only accounted for 12-18% of total N, but particulate P accounted for 30-50% and DOP accounted for an additional 40-50% of total P. Landscape characteristics may in fact be better predictors of spatial variability in particulate-P and DOP than PO4-P. Nonetheless, the landscape models that we have developed for DIN and DOM flux can be used by local watershed managers to predict changes in water quality in response to changes in land use.

Daley, M. L.; McDowell, W. H.

2010-12-01

100

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

NASA Astrophysics Data System (ADS)

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.

Mohsin, Muhammad; Kazianka, Hannes; Pilz, Jürgen

2013-04-01

101

87Sr/86Sr and major ion composition of rainwater of Ahmedabad, India: Sources of base cations  

NASA Astrophysics Data System (ADS)

Rainwater samples from Ahmedabad, an urban site in India are analysed for their chemical composition and Sr isotopic ratio. Dominance of Ca in the cation budget indicates its importance in the acid neutralization whereas SO4 and NO3 dominate the anion budget. The major ion concentrations measured in this study are on the lower side of the range reported in the previous study (Rastogi and Sarin, 2007) from the same site. Na and Cl show very good correlation with ratio similar to the seawater ratio, implying their marine origin. Na concentration in these samples has been used as a proxy to calculate the non sea salt fraction of other major ions. Non sea salt Ca and Mg vary from 99.0% to 99.6% and 24.6% to 89.1% of the measured Ca and Mg respectively whereas non sea salt component of SO4 and HCO3 contribute 84.3% to 98.9% and 99.1% to 99.9% respectively. Sr concentrations in these rainwaters vary from 32 to 191 nM and 87Sr/86Sr ranges from 0.70878 to 0.71027. Sr concentration shows a very good correlation (coefficient 0.93) with the non-sea salt component of Ca and Mg indicating their continental sources and having similar provenances. Carbonates and basalts seem to contribute significantly to dissolved base cations of the rainwaters. The basalts from Deccan region, which is isotopically indistinguishable from the African basalts and the silicate and carbonates from African region along with the sediments from the Ganga plain (which is originated from the Himalayan lithologies) could be potential dust sources for this particular site. The sources of dissolved base cations deduced from Sr isotope composition of the rainwaters are consistent with wind back trajectory data obtained from NOAA HYSPLIT model.

Chatterjee, Jayati; Singh, Sunil Kumar

2012-12-01

102

Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal  

SciTech Connect

The Ganga-Brahmaputra, one of the worlds's largest river systems, is first in terms of sediment transport and fourth in terms of water discharge. A detailed and systematic study of the major ion chemistry of these rivers and their tributaries, as well as the clay mineral composition of the bed sediments has been conducted. The chemistry of the highland rivers are all dominated by carbonate weathering; (Ca + Mg) and HCO{sub 3} account for about 80% of the cations and anions. In the lowland rivers, HCO{sub 3} excess over (Ca + Mg) and a relatively high contribution of (Na + K) to the total cations indicate that silicate weathering and/or contributions from alkaline/saline soils and ground waters could be important sources of major ions to these waters. The chemistry of the Ganga and the Yamuna in the lower reaches is by and large dictated by the chemistry of their tributaries and their mixing proportions. The highland rivers weather acidic rocks, whereas the others flow initially through basic effusives. The Ganga-Brahmaputra river system transports about 130 million tons of dissolved salts to the Bay of Bengal, which is nearly 3% of the global river flux to the oceans. The chemical denudation rates for the Ganga and the Brahmaputra basins are about 72 and 105 tons{center dot}km{sup {minus}2}{center dot}yr{sup {minus}1}, respectively, which are factors of 2 to 3 higher than the global average. The high denudation rate, particularly in the Brahmaputra, is attributable to high relief and heavy rainfall.

Sarin, M.M.; Krishnaswami, S.; Dilli, K.; Somayajulu, B.L.K. (Physical Research Laboratory, Ahmedabad (India)); Moore, W.S. (Univ. of South Carolina (USA))

1989-05-01

103

Energy and pitch angle-resolved measurements of escaping helically trapped energetic ions at the small major radius side of the compact helical system  

NASA Astrophysics Data System (ADS)

We have developed and installed a new, second escaping fast ion probe for the small major radius side of the compact helical system. This is a Tokamak Fusion Test Reactor type scintillator-based probe and is intended to detect unconfined helically trapped fast ions whose orbits largely deviate from magnetic flux surfaces. We observed a localized light spot on the scintillator screen in neutral beam-heated discharges and it was confirmed to be a true fast ion signal. The analysis suggests that the probe detects partially thermalized, pitch angle scattered beam ions.

Isobe, M.; Darrow, D. S.; Kotani, J.; Shimizu, A.; Suzuki, C.; Yoshimura, Y.; Minami, T.; Takahashi, C.; Nagaoka, K.; Nishimura, S.; Toi, K.; Matsuoka, K.; Okamura; The, S.

2003-03-01

104

Effect of cobalt ions on the metabolism of some volatile and polar compounds in the marine invertebrates Mytilus galloprovincialis and Actinia equina  

Microsoft Academic Search

The compositions of the volatile and polar fractions from two coexisting Black Sea invertebrates, the mussel Mytilus galloprovincialis and the beadlet anemone Actinia equina, were established. The main metabolites in the volatile fraction from the investigated animals appeared to be methyl esters of fatty acids and fatty aldehydes. In the polar fraction from both animals low concentrations of free acids

Jordan Nechev; Kamen Stefanov; Diana Nedelcheva; Simeon Popov

2007-01-01

105

Characterizing interactions between surface water and groundwater in the Jialu River basin using major ion chemistry and stable isotopes  

NASA Astrophysics Data System (ADS)

The Jialu River, a secondary tributary of the Huaihe River, has been severely contaminated from major contaminant sources, such as a number of untreated or lightly treated sewage waste in some cities. Groundwater along the river is not an isolated component of the hydrologic system, but is instead connected with the surface water. This study aims to investigate temporal and spatial variations in water chemistry affected by humans and to characterize the relationships between surface water (e.g. reservoirs, lakes and rivers) and groundwater near the river in the shallow Quaternary aquifer. Concentration of Cl- in north Zhengzhou City increased prominently due to the discharge of a large amount of domestic water. Nitrate and potassium show maximum concentrations in groundwater in Fugou County. These high levels can be attributed to the use of a large quantity of fertilizer over this region. Most surface water appeared to be continuously recharged from the surrounding groundwater (regional wells) based on comparison surface water with groundwater levels, stable-isotopes and major ion signatures. However, the groundwater of a transitional well (location SY3) seemed to be recharged by river water via bank infiltration in September 2010. Fractional contributions of river water to the groundwater were calculated based on isotopic and chemical data using a mass-balance approach. Results show that the groundwater was approximately composed of 60-70% river water. These findings should be useful for a better understanding of hydrogeological processes at the river-aquifer interface and ultimately benefit water management in the future.

Yang, L.; Song, X.; Zhang, Y.; Han, D.; Zhang, B.; Long, D.

2012-11-01

106

Volatiles from Syzygium paniculatum fruit.  

PubMed

The volatile compounds of Syzygium paniculatum Banks ex Gaertn. fruit were isolated by simultaneous distillation-solvent extraction and analyzed by gas chromatography-flame ionization detectection and gas chromatography-mass spectrometry. A total of 155 volatile constituents were identified, accounting for 24.5 mg/kg of the fruit composition. Major compounds were alpha-pinene (32.8% of the total composition), (Z)-beta-ocimene (21.8%), limonene (6.9%), and alpha-terpineol (5.1%), indicating that the volatile composition of the fruit is more rich in terpenes. PMID:23472477

Quijano-Célis, Clara E; Echeverri-Gil, Daniel; Ruiz, Yinet; Pino, Jorge A

2013-01-01

107

Secular variation in the major-ion chemistry of seawater: Evidence from fluid inclusions in Cretaceous halites  

NASA Astrophysics Data System (ADS)

The major-ion (Mg2+, Ca2+, Na+, K+, SO42-, and Cl-) chemistry of Cretaceous seawater was determined from analyses of seawater-derived brines preserved as fluid inclusions in marine halites. Fluid inclusions in primary halite from three evaporite deposits were analyzed by the environmental scanning electron microscopy (ESEM) X-ray energy dispersive spectrometry (EDS) technique: the Early Cretaceous (Aptian, 121.0 112.2 Ma) of the Sergipe basin, Brazil and the Congo basin, Republic of the Congo, and the Early to Late Cretaceous (Albian to Cenomanian, 112.2 93.5 Ma) of the Khorat Plateau, Laos, and Thailand. The fluid inclusions in halite indicate that Cretaceous seawater was enriched several fold in Ca2+, depleted in SO42-, Na+, and Mg2+, and had lower Na+/Cl-, Mg2+/Ca2+, and Mg2+/K+ ratios compared to modern seawater. Elevated Ca2+ concentrations, with Ca2+ > SO42- at the point of gypsum saturation, allowed Cretaceous seawater to evolve into Mg2+ Ca2+ Na+ K+ Cl- brines lacking measurable SO42-.The major-ion composition of Cretaceous seawater was modeled from fluid inclusion chemistries for the Aptian and the Albian-Cenomanian. Aptian seawater was extreme in its Ca2+ enrichment, more than three times higher than present day seawater, with a Mg2+/Ca2+ ratio of 1.1 1.3. Younger, Albian-Cenomanian seawater had lower Ca2+ concentrations, and a higher Mg2+/Ca2+ ratio of 1.2 1.7. Cretaceous (Aptian) seawater has the lowest Mg2+/Ca2+ ratios so far documented in Phanerozoic seawater from fluid inclusions in halite, and within the range chemically favorable for precipitation of low-Mg calcite ooids and cements. Results from halite fluid inclusions, together with Mg2+/Ca2+ ratios measured from echinoderm and rudist calcite, all indicate that Early Cretaceous seawater (Hauterivian, Barremian, Aptian, and Albian) had lower Mg2+/Ca2+ ratios than Late Cretaceous seawater (Coniacian, Santonian, and Campanian). Low Aptian-Albian Mg2+/Ca2+ seawater ratios coincide with negative excursions of 87Sr/86Sr ratios and ?34SSO4, and peak Cretaceous ocean crust production rates, all of which suggests a link between seawater chemistry and midocean ridge hydrothermal brine flux.

Timofeeff, Michael N.; Lowenstein, Tim K.; da Silva, Maria Augusta Martins; Harris, Nicholas B.

2006-04-01

108

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

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.

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

2000-01-01

109

The volatile compound BinBase mass spectral database  

PubMed Central

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.

2011-01-01

110

Influence of the major ions of sea water on the adsorption of simple organic acids by goethite  

SciTech Connect

The adsorption of oxalic, phthalic, salicylic, and lactic acids on goethite from 0.53 M NaCl and from synthetic major ion sea water is examined to determine the effect of Mg, Ca, and SO/sub 4/ on the adsorption behavior of the organic compounds. The comparison shows that organic acid adsorption is suppressed in sea water relative to the NaCl system. Successive additions of SO/sub 4/, Mg, and Ca in their natural ionic proportions found in sea water to 0.53 M NaCl indicate that sulfate suppresses the adsorption of all the organic acids, especially in the low pH range. The addition of Mg also suppresses the adsorption of oxalic and phthalic acids while the addition of Ca suppresses lactic acid adsorption. The effect of SO/sub 4/, Mg and Ca on the adsorption of the organic acids is due to competition for available binding sites and the formation of solution complexes which either do not absorb or weakly absorb.

Balistrieri, L.S.; Murray, J.W.

1987-05-01

111

Major ion chemistry, weathering processes and water quality assessment in upper catchment of Damodar River basin, India  

NASA Astrophysics Data System (ADS)

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected and analysed for pH, EC, TDS, F, Cl, HCO3, SO4, NO3, Ca, Mg, Na and K. In general, Ca, Na, Mg, HCO3 and Cl dominate, except in samples from mining areas which have higher concentration of SO4. Water chemistry of the area reflects continental weathering, aided by mining and other anthropogenic impacts. Limiting groundwater use for domestic purposes are contents of TDS, F, Cl, SO4, NO3 and TH that exceed the desirable limits in water collected from mining and urban areas. The calculated values of SAR, RSC and %Na indicate good to permissible use of water for irrigation. High salinity, %Na, Mg-hazard and RSC values at some sites limit use for agricultural purposes.

Singh, Abhay Kumar; Mondal, G. C.; Kumar, Suresh; Singh, T. B.; Tewary, B. K.; Sinha, A.

2008-04-01

112

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

Microsoft Academic Search

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

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

2003-01-01

113

Tracing groundwater input into Lake Vanda, Wright Valley, Antarctica using major ions, stable isotopes and noble gas  

NASA Astrophysics Data System (ADS)

The McMurdo Dry Valleys (MDV), Antarctica, is the largest ice-free region on Antarctica. Lake Vanda, located in central Wright Valley, is the deepest lake among the MDV lakes. It has a relatively fresh water layer above 50 m with a hypersaline calcium-chloride brine below (50-72 m). The Onyx River is the only stream input into Lake Vanda. It flows westward from the coastal Lower Wright Glacier and discharges into Lake Vanda. Suggested by the published literature and this study, there has been and may still be groundwater input into Lake Vanda. Stable isotopes, major ions, and noble gas data from this study coupled with previously published data indicate that the bottom waters of Lake Vanda have had significant contributions from a deep groundwater system. The dissolved gas of the bottom waters of Lake Vanda display solubility concentrations rather than the Ar-enriched dissolved gas seen in the Taylor Valley lakes (such as Lake Bonney). The isotopic data indicate that the bottom calcium-chloride-brine of Lake Vanda has undergone very little evaporation. The calcium-chloride chemistry of the groundwater that discharges into Lake Vanda most likely results from the chemical weathering and dissolution of cryogenic evaporites (antarcticite and gypsum) within the glacial sediments of Wright Valley. The high calcium concentrations of the brine have caused gypsum to precipitate on the lake bottom. Our work also supports previous physical and chemical observations suggesting that the upper portion actively circulates and the hypersaline bottom layer does not. The helium and calcium chloride values are concentrated at the bottom, with a very narrow transition layer between it and the above fresh water. If the freshwater layer did not actively circulate, then diffusion over time would have caused the helium and calcium chloride to slowly permeate upwards through the water column.

Dowling, C. B.; Poreda, R. J.; Snyder, G. T.

2008-12-01

114

Characterization of the major laccase isoenzyme from Trametes pubescens and regulation of its synthesis by metal ions.  

PubMed

The major laccase isoenzyme LAP2 secreted by the white-rot basidiomycete Trametes pubescens in response to high copper concentrations was purified to apparent electrophoretic homogeneity using anion-exchange chromatography and gel filtration. The monomeric protein has a molecular mass of 65 kDa, of which 18% is glycosylation, and a pI value of 2.6. The pH optima of the laccase depend on the substrates oxidized and show bell-shaped pH activity profiles with an optimum of 3-4.5 for phenolic substrates such as 2,6-dimethoxyphenol or syringaldazine, while the non-phenolic substrates ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] and ferrocyanide show a monotonic pH profile with a rate increasing with decreasing pH. The catalytic efficiencies k(cat)/K(m) determined for some of its substrates were 48 x 10(6), 47 x 10(6), 20 x 10(6) and 7 x 10(6) M(-1) s(-1) for ABTS, syringaldazine, ferrocyanide and oxygen, respectively. Furthermore, the gene lap2 encoding the purified laccase was cloned and its nucleotide sequence determined. The gene consists of 1997 bp, with the coding sequence interrupted by eight introns and flanked by an upstream region in which putative CAAT, TATA, MRE and CreA consensus sequences were identified. Based on Northern analysis containing total RNA from both induced and uninduced cultures, expression of lap2 is highly induced by copper, which is also corroborated by an increase in laccase activity in response to copper. A stimulating effect of various other heavy metal ions on laccase synthesis was also observed. In addition to induction, a second regulatory mechanism seems to be repression of lap2 transcription by glucose. PMID:12101303

Galhaup, Christiane; Goller, Sabine; Peterbauer, Clemens K; Strauss, Josef; Haltrich, Dietmar

2002-07-01

115

SPME-GC-MS versus Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) analyses for the study of volatile compound generation and oxidation status during dry fermented sausage processing.  

PubMed

The use of selected ion flow tube mass spectrometry (SIFT-MS) and gas chromatography-mass spectrometry together with solid phase microextraction (GC-MS-SPME) has been compared in the analysis of volatile compounds during dry fermented sausage processing. Thus, the headspace (HS) of samples of dry fermented sausages with different fat contents was analyzed during their manufacture using both techniques, and significant and positive correlations were found between SIFT-MS and SPME-GC-MS measurements for the compounds pentanal, hexanal, 2-heptenal, octanal, 2-nonenal, 2-butanone, 2-pentanone, ethanol, acetic acid, and hexanoic acid. The oxidative status of fermented sausages during processing was also evaluated, and a significant correlation was obtained between the HS concentration of lipid autoxidation volatile compounds measured by SIFT-MS and SPME-GC-MS and the level of thiobarbituric acid reactive substances (TBARS) in the sausage. The hexanal measured by SIFT-MS resulted in a higher correlation coefficient (r = 0.936) than that obtained using SPME-GC-MS (r = 0.927). SIFT-MS is shown to be a fast, real time analytical technique for monitoring changes in the profile of volatile compounds in dry fermented sausages during processing and a useful tool to evaluate the oxidative status of meat products. PMID:21294565

Olivares, Alicia; Dryahina, Kseniya; Navarro, José Luis; Smith, David; Span?l, Patrik; Flores, Mónica

2011-02-04

116

Volatile Production of Irradiated Normal, PSE, and DFD Pork  

Microsoft Academic Search

With both aerobic and vacuum packaging, irradiation increased the production of sulfur-containing volatiles in all three pork types (normal, PSE, DFD) at day 0, but did not increase hexanal - the major indicator volatile of lipid oxidation. PSE pork produced the lowest amount of total sulfur-containing volatiles in both aerobically and vacuum-packaged pork at day 0. Majority of sulfurcontaining volatiles

D. U. Ahn; K. C. Nam; M. Du; C. Jo

2000-01-01

117

Hedging options under transaction costs and stochastic volatility  

Microsoft Academic Search

In this paper, we consider the problem of hedging contingent claims on a stock under transaction costs and stochastic volatility. Extensive research has clearly demonstrated that the volatility of most stocks is not constant over time. As small changes of the volatility can have a major impact on the value of contingent claims, hedging strategies should try to eliminate this

Jacek Gondzio; Roy Kouwenberg; Ton Vorst

2003-01-01

118

Multi-Decadal Analysis of Atmospheric Aerosol Loading Based on Major Ion and Stable Isotope Geochemistry of Glacial Ice From the Siberian Altai  

Microsoft Academic Search

Analysis of a deep alpine ice core from the mid-latitude Siberian Altai is presented. The 170m core in storage and processing at the University of Idaho is examined to 50m on the basis of annual layer identification and dating, visual stratigraphy, major ion concentration, stable (delta18O,delta2H) and radiogenic (delta3H) isotope variability using multivariate and time series statistical methods. The core

D. Joswiak; E. Aizen; V. Aizen

2006-01-01

119

Emissions of major gaseous and particulate species during experimental burns of southern African biomass  

Microsoft Academic Search

Characteristic vegetation and biofuels in major ecosystems of southern Africa were sampled during summer and autumn 2000 and burned under semicontrolled conditions. Elemental compositions of fuels and ash and emissions of CO2, CO, CH3COOH, HCOOH, NOX, NH3, HONO, HNO3, HCl, total volatile inorganic Cl and Br, SO2 and particulate C, N, and major ions were measured. Modified combustion efficiencies (MCEs,

William C. Keene; Jürgen M. Lobert; Paul J. Crutzen; John R. Maben; Dieter H. Scharffe; Tobias Landmann; Christelle Hély; Conrad Brain

2006-01-01

120

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

PubMed

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

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

2013-01-14

121

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)

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.

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

2003-12-01

122

MAJOR ION CHEMISTRY, SOLUTE ACQUISITION PROCESSES AND QUALITY ASSESSMENT OF MINE WATER IN DAMODAR VALLEY COALFIELDS, INDIA  

Microsoft Academic Search

An attempt has been made to carry out qualitative assessment of mine water discharges from the selected coal mining areas of Jharia, Raniganj and West Bokaro coalfields of Damodar Basin. 184 mine water samples were analyzed for pH, electrical conductivity (EC), major cations (Ca, Mg, Na, K), major anions (HCO3, SO4, Cl, NO3), and heavy metals (Fe, Mn, Cu, Zn,

ABHAY KUMAR SINGH; G. C. MONDAL; B. K. TEWARY; A. SINHA

2009-01-01

123

Volatile substance abuse.  

PubMed

Volatile substance abuse (VSA) (glue sniffing, inhalant abuse, solvent abuse), the deliberate inhalation of volatile substances in order to achieve intoxication, has now been reported from most parts of the world, mainly among adolescents, individuals living in remote communities and those whose occupations give ready access to abusable substances. Solvents from contact adhesives, notably toluene, petrol (gasoline), halogenated solvents, volatile hydrocarbons such as those found in cigarette lighter refills, aerosol propellants, halocarbon fire extinguishers, and inhalational anaesthetics may be abused in this way. VSA gives rise to dose-related effects similar to those of other hypnosedatives. Small doses can rapidly lead to euphoria and other disturbances of behaviour similar to those caused by ethanol (alcohol), and may also induce delusions and hallucinations. Higher doses may produce life-threatening effects such as convulsions and coma. Death may ensue indirectly after, for example, inhalation of vomit, or from direct cardiac or central nervous system toxicity. Chronic abuse of toluene-containing products and of chlorinated solvents such as 1,1,1-trichloroethane, for example, can produce severe organ damage, especially in the liver, kidneys, and brain. Drunken behaviour, unexplained listlessness, anorexia and moodiness may result from VSA, especially in children and adolescents. The hair, breath and clothing may smell of solvent, and empty adhesive tubes or other containers, potato crisp bags, cigarette lighter refills, and aerosol spray cans are often found. Toxicological examination of blood and tissue specimens is especially important in confirming a diagnosis of sudden VSA-related death. The development and evaluation of strategies for the treatment of chronic abusers and for prevention are major challenges for the future. PMID:7866398

Flanagan, R J; Ives, R J

1994-01-01

124

Analysis of secondary organic aerosol using a Micro-Orifice Volatilization Impactor (MOVI) coupled to an ion trap mass spectrometer with atmospheric pressure chemical ionization (APCI-IT/MS)  

NASA Astrophysics Data System (ADS)

We describe the development and characterization of a Micro-Orifice Volatilization Impactor (MOVI) which is coupled to an ion trap mass spectrometer with atmospheric pressure chemical ionization (APCI-IT/MS), and its application in laboratory and field measurements. The MOVI-APCI-IT/MS allows the quantification of organic acids and other oxidation products of volatile organic compounds (VOCs) in secondary organic aerosols (SOA) on a semi-continuous basis. Furthermore, the vapor pressure and saturation concentration of the particle components can be estimated. The MOVI was first described in 2010 by Yatavelli and Thornton (Yatavelli and Thornton, 2010). It is a single stage, multi-nozzle impactor with 100 nozzles, each having a diameter of 150 ?m. At a flow-rate of 10 L·min-1 air is drawn through the MOVI and particles are collected on a deposition plate. The cut-point diameter (d50, diameter of 50% collection efficiency) is at 130 nm. A low pressure-drop of only 5.3% of atmospheric pressure behind the nozzles allows collecting not only low-volatile but even semi-volatile compounds, which are an important part of SOA. After collecting particles hydrocarbon-free synthetic air is led over the collection surface into the APCI-IT/MS and the collection surface is heated up to 120 ° C in less than 200 s, volatilizing the sampled SOA. The vaporized compounds are transferred into the ion source and subsequently analyzed by mass spectrometry. Due to the soft ionization at atmospheric pressure the obtained mass spectra show only low fragmentations and can easily be interpreted. In laboratory experiments the MOVI-APCI-IT/MS was used for the chemical analysis of SOA generated from ?-pinene-ozonolysis in a smog chamber. The limit of detection was found at 7.3 ng for pinic acid. The vapor pressure log p0 and the saturation concentration C25* for pinic acid were calculated from the desorption temperature using the method presented by Faulhaber et al. (Faulhaber et al., 2009). Furthermore, in summer 2011 the MOVI-APCI-IT/MS was successfully tested in field measurements during the "Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen - Rocky Mountain Biogenic Aerosol Study" (BEACHON-RoMBAS) in a ponderosa pine woodland in the southern Rocky Mountains of North America. The study was focused on understanding the formation, growth and properties of biogenic organic aerosol. We measured the composition of the aerosol particles and determined the concentration of pinic acid and isobaric substances. By means of intercomparison studies with other instruments like an aerosol mass spectrometer (AMS) and a MOVI coupled to a chemical ionization mass spectrometer (CIMS) we could validate our measurements.

Brueggemann, M.; Vogel, A.; Hoffmann, T.

2012-04-01

125

Constituent elements of insoluble and non-volatile particles during the Last Glacial Maximum exhibited in the Dome Fuji (Antarctica) ice core  

NASA Astrophysics Data System (ADS)

In order to find environmental signals based on the dust and calcium-ion concentrations in ice cores, we determine the constituent elements of residue particles obtained after melting ice samples. We have designed a sublimating system that operates at -45°C, below the eutectic temperatures of major salts. This system permits us to obtain a great many non-volatile particles. After studying the non-volatile particles, we immersed them in water to remove soluble particles and compounds. We thereby analyzed a total of 1272 residue particles (from the melted sample), 2418 non-volatile particles (after sublimation) and 1463 insoluble particles taken from five sections of Last Glacial Maximum ice from the Dome Fuji (Antarctica) ice core. Their constituent elements were determined by scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) and compared to the dust, calcium-ion and sodium-ion concentrations measured by ion chromatography. Our results indicate that >99.9% of the insoluble particles contain silicon but no sulfur, nitrogen or chlorine. A significant number of the non-volatile particles, however, contain sulfur and chlorine. We conclude that insoluble dust consists mostly of silicate, that almost all calcium ions originate from calcium sulfate and that almost all sodium ions originate from sodium sulfate and sodium chloride.

Iizuka, Yoshinori; Miyake, Takayuki; Hirabayashi, Motohiro; Suzuki, Toshitaka; Matoba, Sumito; Motoyama, Hideaki; Fujii, Yoshiyuki; Hondoh, Takeo

126

Glycine betaine and potassium ion are the major compatible solutes in the extremely halophilic methanogen Methanohalophilus strain Z7302.  

PubMed Central

Methanohalophilus strain Z7302 was previously isolated from a hypersaline environment and grows over a range of NaCl concentrations from 1.7 to 4.4 M. We examined the relationships between cell growth rate, cell volume, and intracellular solute concentrations with increasing salinity. This extremely halophilic methanogen synthesized three zwitterionic compounds, beta-glutamine, N epsilon-acetyl-beta-lysine, and glycine betaine, and also accumulated potassium ion as compatible solutes to balance the external and internal osmotic pressures. Potassium and glycine betaine were the predominant compatible solutes when Methanohalophilus strain Z7302 was grown at high external NaCl concentrations and approached intracellular levels of 3 and 4 M, respectively.

Lai, M C; Gunsalus, R P

1992-01-01

127

Transactions, Volume, and Volatility  

Microsoft Academic Search

We show that the positive volatility-volume relation documented by numerous researchers actually reflects the positive relation between volatility and the number of transactions. Thus, it is the occurrence of transactions per se, and not their size, that generates volatility; trade size has no information beyond that contained in the frequency of transactions. Our results suggest that theoretical research needs to

Charles M. Jones; Gautam Kaul; Marc L Lipson

1994-01-01

128

Spatial and seasonal variability of water-soluble ions in PM2.5 aerosols in 14 major cities in China  

NASA Astrophysics Data System (ADS)

We analyzed PM2.5 aerosols from 14 major cities in China for concentrations of water-soluble (WS) major and trace elements (Na, Mg, Ca, K, Fe, Mn, Zn, Rb, Sr, Ba, Pb, S and Cl). The main focus was to examine patterns in spatial distribution and seasonal variability. Using principal component analysis, we identified three general sources for WS-elements in aerosols as anthropogenic, seasalts and fine dust particles originating from soils. The spatial patterns identified show that anthropogenic activity is the most important factor influencing the concentration of heavy metals in aerosols. Concentrations of WS-S, Zn and Pb were correlated with the locations of major industrial zones, and regulated by topography and seasonal weather patterns. We found higher WS-metals concentrations during the winter season, probably related to coal combustion in northern China. Moderate correlations of WS-S, Zn, Pb and Cl suggest that coal combustion releases. The seasonal pattern in WS-Fe concentrations shows the importance of acid precipitation events where coal combustion contributes to additional Fe (II) deposition. The findings of this study support the argument that WS-S in fine particles enhanced the production of hydrogen ions act to reduce the pH values of precipitation. Our interpretation of these spatial and seasonal patterns in WS-major and trace elements in aerosols highlights the need for continued research on trends in acidic deposition in major industrial cities in China.

Cheng, Miao-Ching; You, Chen-Feng; Cao, Junji; Jin, Zhangdong

2012-12-01

129

Volatile Constituents of Montanoa tomentosa and Lippia graveolens.  

PubMed

The constituents of the volatile oils of MONTANOA TOMENTOSA and LIPPIA GRAVEOLENS, were investigated using capillary GC/MS. Borneol acetate, beta-cubebene, and beta-caryophyllene were found to be the major constituents of the volatile oil of M. TOMENTOSA, while P-cymene, 1,8-cineol, thymol, and carvacrol were the major volatile components of L. GRAVEOLENS. The possible correlation between the high concentration of monoterpenes and the alleged antifertility effect of the title plants is discussed. PMID:17269076

Compadre, C M; Hussain, R A; Leon, I; Enríquez, R G

1987-10-01

130

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

NASA Astrophysics Data System (ADS)

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.

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

131

CHARACTERIZATION OF CORIANDER (CORIANDRUM SATIVUM L.) SEEDS AND LEAVES: VOLATILE AND NON VOLATILE EXTRACTS  

Microsoft Academic Search

The main aim of this study was the characterization of coriander essential oil. The major volatile compounds in coriander seed essential oil were linalool, ?-terpinene, ?-pinene, camphor, decanal geranyl acetate, limonene, geraniol, camphene and D- limonene. While the major volatile compounds identified in coriander leaves essential oil (CLEO) were (E)-2-decenal, linalool, (E)-2-dodecenal, (E)-2-tetradecenal, 2-decen-1-ol, (E)-2-undecenal, dodecanal, (E)-2-tridecenal, (E)-2-hexadecenal, pentadecenal, ?-pinene.

Muhammad Khuram Shahwar; Ahmed Hassan El-Ghorab; Faqir Muhammad Anjum; Masood Sadiq Butt; Shahzad Hussain; Muhammad Nadeem

2011-01-01

132

Characterization of Coriander (Coriandrum sativum L.) Seeds and Leaves: Volatile and Non Volatile Extracts  

Microsoft Academic Search

The main aim of this study was the characterization of coriander essential oil. The major volatile compounds in coriander seed essential oil were linalool, ?-terpinene, ?-pinene, camphor, decanal geranyl acetate, limonene, geraniol, camphene, and D-limonene, while the major volatile compounds identified in coriander leaves essential oil were (E)-2-decenal, linalool, (E)-2-dodecenal, (E)-2-tetradecenal, 2-decen-1-ol, (E)-2-undecenal, dodecanal, (E)-2-tridecenal, (E)-2-hexadecenal, pentadecenal, and ?-pinene. The

Muhammad Khuram Shahwar; Ahmed Hassan El-Ghorab; Faqir Muhammad Anjum; Masood Sadiq Butt; Shahzad Hussain; Muhammad Nadeem

2012-01-01

133

Volatile Selenium Flux in the Great Salt Lake  

Microsoft Academic Search

Volatilization of selenium has been proven to be the major source of selenium vapor from oceans and estuaries and it may be the major mechanism of permanent selenium removal from the Great Salt Lake (other than brine shrimp harvest). However, the volatilization flux of selenium from the Great Salt Lake has not been previously measured due to challenges of analysis

X. Diaz; W. P. Johnson

2006-01-01

134

Characterizing interactions between surface water and groundwater in the Jialu River basin using major ion chemistry and stable isotopes  

NASA Astrophysics Data System (ADS)

The Jialu River, a secondary tributary of the Huaihe River, has been severely contaminated for the major contaminant sources, such as a number of untreated or lightly treated sewage wastes in some cities. Groundwater along the river is not an isolated component of the hydrologic system, but instead connected with the surface water. This study aims to characterize the relationships between surface water (e.g. reservoirs, lakes and rivers) and groundwater near the river in the shallow Quaternary aquifer. The concentration of Cl- in North Zhengzhou City increased prominently due to the discharge of a large amount of domestic water. Nitrate and potassium show maximum concentrations in groundwater in Fugou County. These high levels can be attributed to the use of a large quantity of fertilizer over this region. The regional well had water with a constant stable isotopic signature, which illustrates that the groundwater never or rarely receive recharge from surface water. However, the groundwater of transitional well (location SY3) seemed to be recharged by river water via bank infiltration in September 2010. Fractional contributions of river water to the groundwater were calculated based on isotopic and chemical data using a mass-balance approach. Results show that the groundwater was approximately composed of 60-70% river water. These findings would be useful for a better understanding of hydrogeological processes at the river-aquifer interface and ultimately benefit water management in the future.

Yang, L.; Song, X.; Zhang, Y.; Han, D.; Zhang, B.; Long, D.

2012-05-01

135

Mercury Volatility in the Presence of Reducing Agents  

SciTech Connect

This document described a laboratory study designed to determine whether mercury is, in fact, reduced by bisulfite ion and ammonia and, if so, whether the reduced mercury is volatilized at the boiling point of water. The primary conclusions resulting from this study are that both bisulfite ion and ammonia are capable of reducing mercury in solution and that, when reduced, the mercury will all be volatilized and carried into the distillate.

Bibler, J.P.

2001-03-23

136

Volatility of power markets  

Microsoft Academic Search

Volatility features of the Nordic day ahead power spot market for a 12-year period up till May 2004 are studied. The daily logarithmic volatility was measured for this period to be about 16%. This level is well above what is observed for most other well-studied financial markets. Volatility clustering, log-normal distribution, and long-range correlations are found to be striking features

Ingve Simonsen

2005-01-01

137

Food price volatility  

PubMed Central

The high food prices experienced over recent years have led to the widespread view that food price volatility has increased. However, volatility has generally been lower over the two most recent decades than previously. Variability over the most recent period has been high but, with the important exception of rice, not out of line with historical experience. There is weak evidence that grains price volatility more generally may be increasing but it is too early to say.

Gilbert, C. L.; Morgan, C. W.

2010-01-01

138

Iodine volatility. [PWR; BWR  

SciTech Connect

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.

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

1984-01-01

139

Kinetics of the reactions of acetone and glyoxal with O2+ and NO+ ions and application to the detection of oxygenated volatile organic compounds in the atmosphere by chemical ionization mass spectrometry  

NASA Astrophysics Data System (ADS)

In situ measurements of oxygenated volatile organic compounds (OVOC) in the upper troposphere-lower stratosphere (UTLS) have gained strong interest because these compounds may be transported during convective events to the UTLS, where they may contribute to the HOx budget thus influencing the chemistry of ozone. With the aim to quantify OVOC of similar mass (58 u) by chemical ionization mass spectrometry (CIMS), ion-molecule reactions of acetone and glyoxal with O2+ and NO+ have been studied. O2+ reacts at the theoretical collision rate with acetone and glyoxal, with room-temperature rate constant values of (3.1 ± 0.7) × 10-9 and (1.8 ± 0.4) × 10-9 cm3 molecule-1 s-1, respectively, independent of pressure. The charge transfer product ion (m/z 58) and a specific fragment product ion are formed for each reaction. NO+ reacts with acetone and glyoxal with a rate constant lower than the collision rate in N2 buffer gas at 1.7 hPa, leading to the formation of the association product in both cases as single reaction productE The rate constants increase with pressure at 295 K for both ranges of 1.2-19.2 hPa N2 and 1.3-2.6 hPa He, indicating a falloff kinetic regime. These results are analysed using conventional statistical calculations. Consistency of the rate constants is obtained for both buffer gases and pressure ranges employed, and high-pressure limits are in agreement with the collision rate constants. Troe analytical expressions of the rate constants are derived for use under any pressure and temperature. From the reaction kinetics and mechanisms obtained in this study and others, a scheme is discussed to quantify separately acetone, glyoxal, and propanal in the UTLS by CIMS, using NO+, O2+, and H3O+ as reagent ions, taking into account potential interferences from other important OVOC such as acetaldehyde and from non-methane hydrocarbons such as n-propane, butane and 2-methyl propane.

Guimbaud, C.; Catoire, V.; Bergeat, A.; Michel, E.; Schoon, N.; Amelynck, C.; Labonnette, D.; Poulet, G.

2007-06-01

140

Major-ion chemistry, ?13C and 87Sr/86Sr as indicators of hydrochemical evolution and sources of salinity in groundwater in the Yuncheng Basin, China  

NASA Astrophysics Data System (ADS)

Processes controlling hydrogeochemistry in the Yuncheng Basin, China, were characterised using major-ion chemistry, 87Sr/86Sr ratios and ?13C values. Evapotranspiration during recharge increased solute concentrations by factors of ˜5-50 in deep palaeowaters, while higher degrees of evapotranspiration have occurred in shallow, modern groundwater. Aquifer sediments (loess) contain approximately 15 weight% calcite; trends in groundwater HCO3 concentrations and ?13C values (ranging from -16.4 to -8.2‰) indicate that carbonate weathering is a significant source of DIC. Groundwater 87Sr/86Sr ratios (0.7110-0.7162, median of 0.7116) are similar to those in both loess carbonate (0.7109-0.7116) and local rainfall (0.7112), and are significantly lower than Sr in aquifer silicates (0.7184-0.7251). Despite evidence for substantial carbonate dissolution, groundwater is generally Ca-poor (< 10% of total cations) and Na-rich, due to cation exchange. Saturation with respect to carbonate minerals occurs during or soon after recharge (all calcite and dolomite saturation indices are positive). Subsequent carbonate dissolution in the deep aquifer must occur as a second-stage process, in response to Ca loss (by ion exchange) and/or via incongruent dissolution of dolomite and impure calcite. The latter is consistent with positive correlations between ?13C values and Mg/Ca and Sr/Ca ratios ( r 2 = 0.32 and 0.34).

Currell, Matthew J.; Cartwright, Ian

2011-06-01

141

Molecular Detection of Targeted Major Histocompatibility Complex I-Bound Peptides Using a Probabilistic Measure and Nanospray MS3 on a Hybrid Quadrupole-Linear Ion Trap  

PubMed Central

A nanospray MS3 method deployed on a quadrupole linear ion trap hybrid can detect targeted peptides with high dynamic range and high sensitivity from complex mixtures without separations. The method uses a recognition algorithm that is a modification of the relative (Kullback?Leibler, KL) entropy characterization of probabilistic distance to detect if reference MS3 fragmentation patterns are components of acquired MS3 spectra. The recognition reflects the probabilistic structure of physical MS measurements unlike the Euclidean or inner product metrics widely used for comparing spectra. It capably handles spectra with a significant chemical ion background in contrast to the Euclidean metric or the direct relative entropy. The full nanospray MS3 method allows both the detection and quantitation of targets without the need to obtain isotopically labeled standards. By avoiding chromatographic separations and its associated surface losses, the detection can be applied to complex samples on a very limited material scale. The methodology is illustrated by applications to the medically important problem of detecting targeted major histocompatibility complex (MHC) I associated peptides extracted from limited cell numbers.

2010-01-01

142

First Identification of 5,11-Dideoxytetrodotoxin in Marine Animals, and Characterization of Major Fragment Ions of Tetrodotoxin and Its Analogs by High Resolution ESI-MS/MS  

PubMed Central

Even though tetrodotoxin (TTX) is a widespread toxin in marine and terrestrial organisms, very little is known about the biosynthetic pathway used to produce it. By describing chemical structures of natural analogs of TTX, we can start to identify some of the precursors that might be important for TTX biosynthesis. In the present study, an analog of TTX, 5,11-dideoxyTTX, was identified for the first time in natural sources, the ovary of the pufferfish and the pharynx of a flatworm (planocerid sp. 1), by comparison with totally synthesized (?)-5,11-dideoxyTTX, using high resolution ESI-LC-MS. Based on the presence of 5,11-dideoxyTTX together with a series of known deoxy analogs, 5,6,11-trideoxyTTX, 6,11-dideoxyTTX, 11-deoxyTTX, and 5-deoxyTTX, in these animals, we predicted two routes of stepwise oxidation pathways in the late stages of biosynthesis of TTX. Furthermore, high resolution masses of the major fragment ions of TTX, 6,11-dideoxyTTX, and 5,6,11-trideoxyTTX were also measured, and their molecular formulas and structures were predicted to compare them with each other. Although both TTX and 5,6,11-trideoxyTTX give major fragment ions that are very close, m/z 162.0660 and 162.1020, respectively, they are distinguishable and predicted to be different molecular formulas. These data will be useful for identification of TTXs using high resolution LC-MS/MS.

Yotsu-Yamashita, Mari; Abe, Yuka; Kudo, Yuta; Ritson-Williams, Raphael; Paul, Valerie J.; Konoki, Keiichi; Cho, Yuko; Adachi, Masaatsu; Imazu, Takuya; Nishikawa, Toshio; Isobe, Minoru

2013-01-01

143

First identification of 5,11-dideoxytetrodotoxin in marine animals, and characterization of major fragment ions of tetrodotoxin and its analogs by high resolution ESI-MS/MS.  

PubMed

Even though tetrodotoxin (TTX) is a widespread toxin in marine and terrestrial organisms, very little is known about the biosynthetic pathway used to produce it. By describing chemical structures of natural analogs of TTX, we can start to identify some of the precursors that might be important for TTX biosynthesis. In the present study, an analog of TTX, 5,11-dideoxyTTX, was identified for the first time in natural sources, the ovary of the pufferfish and the pharynx of a flatworm (planocerid sp. 1), by comparison with totally synthesized (-)-5,11-dideoxyTTX, using high resolution ESI-LC-MS. Based on the presence of 5,11-dideoxyTTX together with a series of known deoxy analogs, 5,6, 11-trideoxyTTX, 6,11-dideoxyTTX, 11-deoxyTTX, and 5-deoxyTTX, in these animals, we predicted two routes of stepwise oxidation pathways in the late stages of biosynthesis of TTX. Furthermore, high resolution masses of the major fragment ions of TTX, 6,11-dideoxyTTX, and 5,6,11-trideoxyTTX were also measured, and their molecular formulas and structures were predicted to compare them with each other. Although both TTX and 5,6,11-trideoxyTTX give major fragment ions that are very close, m/z 162.0660 and 162.1020, respectively, they are distinguishable and predicted to be different molecular formulas. These data will be useful for identification of TTXs using high resolution LC-MS/MS. PMID:23924959

Yotsu-Yamashita, Mari; Abe, Yuka; Kudo, Yuta; Ritson-Williams, Raphael; Paul, Valerie J; Konoki, Keiichi; Cho, Yuko; Adachi, Masaatsu; Imazu, Takuya; Nishikawa, Toshio; Isobe, Minoru

2013-08-06

144

Identification of the hydrogeochemical processes in groundwater using major ion chemistry: a case study of Penna-Chitravathi river basins in Southern India.  

PubMed

Hydrogeochemical studies were carried out in the Penna-Chitravathi river basins to identify and delineate the important geochemical processes which were responsible for the evolution of chemical composition of groundwater. The area is underlain by peninsular gneissic complex of Archaean age, Proterozoic meta-sediments, and strip of river alluvium. Groundwater samples were collected covering all the major hydrogeological environs in pre- and post-monsoon seasons. The samples were analyzed for major constituents such as Ca2+, Mg2+, Na+, K+, CO3-, HCO3-, Cl-, SO2(-4), NO3-, and F-. The groundwater in general is of Na+-Cl-, Na+-HCO3-, Ca2+-Mg2+-HCO3-, and Ca2+-Mg2+-Cl- types. Na+ among cations and Cl- and/or HCO3- among anions dominate the water; Na+ and Ca2+ are in the transitional state with Na+ replacing Ca2+ and HCO3- Cl- due to physiochemical changes in the aquifer and water-rock interactions. The Ca2+-Mg2+-Cl- HCO3- type water in one third samples suggest that ion exchange and dissolution processes are responsible for its origin. Change in storage of aquifer in a season does not influence the major geochemical makeup of groundwater. Gibbs plots indicate that the evolution of water chemistry is influenced by water-rock interaction followed by evapotranspiration process. The aquifer material mineralogy together with semiarid climate, poor drainage system, and low precipitation factors played major role in controlling groundwater quality of the area. PMID:19941064

Reddy, A G S; Kumar, K Niranjan

2009-11-26

145

Quantitative determination of glycopyrrolate in human plasma by liquid chromatography-electrospray ionization mass spectrometry: the use of a volatile ion-pairing agent during both liquid-liquid extraction and liquid chromatography.  

PubMed

The work presented here deals with the development of a quantitative tool for the determination of the quaternary ammonium anticholinergic glycopyrrolate in human plasma samples. Mepenzolate was used as an internal standard. The plasma samples were subjected to a suitable sample clean-up consisting of a simple and relatively fast, two step liquid-liquid ion-pair extraction procedure. The chromatography, using the same volatile ion-pair reagent heptafluorobutyric acid (HFBA), takes only 10 min. Relative standard deviation of retention times was never above 2.26% (n=36). The method was fully validated based on the US FDA Bioanalytical Method Validation Guidance for Industry. As such, a quantitative ESI-LC-MS(/MS) (TOF mass spectrometry) method was optimized for the absolute quantification of glycopyrrolate in human plasma in a concentration range from 0.101 to 101 ng/mL using a quadratic calibration function (R(2)=0.9995), y=-2.21 x 10(-4) (+/-3.93 x 10(-5))xx(2)+5.85 x 10(-2) (+/-5.27 x 10(-3))xx+4.08 x 10(-3) (+/-4.82 x 10(-4)). For the three QC concentrations (QC(1) 0.252, QC(2) 2.52, and QC(3) 25.2ng/mL) and the LLOQ (0.101 ng/mL), total precision was under 20% (18.0% (n=6) at the LLOQ) and maximum accuracy was 112% (88.9% for the LLOQ, n=6). Absolute matrix effect (maximum 133%+/-9.59, n=3), absolute recovery (better than 41.8%+/-2.22, n=3), relative (inter-subject) matrix effect (maximum 10.9%+/-1.45, n=4) and process efficiency (better than 45.2%+/-5.74, n=3) too were assessed at the 3 QC concentrations. PMID:18977186

Storme, M L; t'Kindt, R S; Goeteyn, W; Reyntjens, K; Van Bocxlaer, J F

2008-10-14

146

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...

147

Volatility and Development  

Microsoft Academic Search

Why is GDP growth so much more volatile in poor countries than in rich ones? We identify three possible reasons: (i) poor countries specialize in fewer and more volatile sectors; (ii) poor countries experience more frequent and more severe aggregate shocks (e.g., from macroeconomic policy); and (iii) poor countries' macroeconomic fluctuations are more highly correlated with the shocks affecting the

Miklós Koren; Silvana Tenreyro

2007-01-01

148

Emerging equity market volatility  

Microsoft Academic Search

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

Geert Bekaert; Campbell R. Harvey

1997-01-01

149

DYNAMIC ANALYSIS OF SORPTION OF VOLATILE ORGANIC COMPOUNDS IN WATER  

Microsoft Academic Search

Chlorinated and brominated volatile organic compounds are among the groundwater pollutants creating major environmental problems. In this study, dynamic behavior of certain volatile organic compounds in water was investigated by using a novel moment technique. Adsorption equilibrium constant and the penetration length of tracers were evaluated by the first absolute and the second central moment expressions derived for a pulse-response

Nail Yasyerli; Ugur Harbili

2008-01-01

150

Volatile flavor compounds in yogurt: a review.  

PubMed

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor. PMID:21108074

Cheng, Hefa

2010-11-01

151

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)

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.

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

2012-12-01

152

Volatile Organic Compounds in Uremia  

PubMed Central

Background Although “uremic fetor” has long been felt to be diagnostic of renal failure, the compounds exhaled in uremia remain largely unknown so far. The present work investigates whether breath analysis by ion mobility spectrometry can be used for the identification of volatile organic compounds retained in uremia. Methods Breath analysis was performed in 28 adults with an eGFR ?60 ml/min per 1.73 m2, 26 adults with chronic renal failure corresponding to an eGFR of 10–59 ml/min per 1.73 m2, and 28 adults with end-stage renal disease (ESRD) before and after a hemodialysis session. Breath analysis was performed by ion mobility spectrometryafter gas-chromatographic preseparation. Identification of the compounds of interest was performed by thermal desorption gas chromatography/mass spectrometry. Results Breath analyses revealed significant differences in the spectra of patients with and without renal failure. Thirteen compounds were chosen for further evaluation. Some compounds including hydroxyacetone, 3-hydroxy-2-butanone and ammonia accumulated with decreasing renal function and were eliminated by dialysis. The concentrations of these compounds allowed a significant differentiation between healthy, chronic renal failure with an eGFR of 10–59 ml/min, and ESRD (p<0.05 each). Other compounds including 4-heptanal, 4-heptanone, and 2-heptanone preferentially or exclusively occurred in patients undergoing hemodialysis. Conclusion Impairment of renal function induces a characteristic fingerprint of volatile compounds in the breath. The technique of ion mobility spectrometry can be used for the identification of lipophilic uremic retention molecules.

Seifert, Luzia; Slodzinski, Rafael; Jankowski, Joachim; Zidek, Walter; Westhoff, Timm H.

2012-01-01

153

Volatile anesthetics-induced neuroinflammatory and anti-inflammatory responses.  

PubMed

Volatile anesthetics have been the major anesthetics used clinically for more than 150 years. They provide all components of general anesthesia and are easy to be applied and monitored with modern equipment and technology. In addition to having anesthetic property, volatile anesthetics have multiple other effects. Many studies have clearly shown that volatile anesthetics can reduce systemic and local inflammatory responses induced by various stimuli in humans and animals. On the other hand, recent animal studies have shown that volatile anesthetics may induce mild neuroinflammation. These dual effects on inflammation may have significant biological implications and are briefly reviewed here. PMID:23915963

Blum, Franziska E; Zuo, Zhiyi

2013-08-01

154

Sub-annual Ice-Core Record of Major Ion and Heavy Metal Variability and Sources in the North Pacific Free Troposphere, Mt. Logan, Yukon, Canada  

NASA Astrophysics Data System (ADS)

The Mt. Logan, Yukon, Canada summit plateau (PR Col; 5300 m.a.s.l.) ice core has been continuously sampled at high resolution (2-3 cm/sample) by a novel ice core melting system with discrete sampling, and analyzed for 8 major ions and 35 trace elements. Co-registered, sub-annual timeseries covering the past 500 years reveal seasonal aerosol fluctuations dominated by dust, with sea-salt contributing less than 5% of sulfate and calcium concentrations. Dating of the top 500 years of the record is by annual layer counting. Concentration spikes of sulfate greater than three times the standard deviation (60 ppb) above the mean (75 ppb) correspond in time with historical explosive volcanic eruptions. Sulfate spikes corresponding in time with large (VEI>4) historical Alaskan eruptions, including Katmai (1912) and St. Augustine (1986), are commonly associated with concentration and crustal enrichment factor spikes in lead, cadmium, antimony, copper, zinc, bismuth and thallium an order of magnitude above background (non-volcanic event) values. Sulfate spikes corresponding in time to large eruptions from distant volcanoes, including Agung (1963), do not show a corresponding rise in heavy metal concentrations. Apart from the periodic spikes in concentration, heavy metal timeseries largely mirror those of the major dust species (Al, Fe), but maintain significantly elevated crustal enrichment factors, probably due primarily to quiescent degassing of volcanoes. Such datasets are necessary to understand the cycling of heavy metals in the free troposphere, including the relative source strength of explosive eruptions vs. quiescent volcanic degassing, and the relative strength of natural vs. anthropogenic sources.

Osterberg, E. C.; Kurbatov, A. V.; Mayewski, P. A.; Kreutz, K. J.; Fisher, D.

2005-12-01

155

Magmatic Volatile Histories From Apatite Phenocrysts  

NASA Astrophysics Data System (ADS)

Apatite phenocrysts contain as part of their structure all the major magmatic volatile elements (H, C, F, S, and Cl). For this reason we have explored the potential for apatite to record magmatic volatile histories [1], and compared the volatile record in apatite with that derived from melt inclusions [2]. Apatite has been observed at many central American volcanoes including Irazu, Arenal, Concepcion, Fuego, and Pacaya, and therefore there is great potential to extend this record, and use it to understand local and regional complexities in magmatic volatile behavior. Our results from Volcan Irazu (Costa Rica) are the first such measurements from the Central American volcanic arc. At Irazu, apatite [2] and melt inclusions [3] from the 1723 eruption have high to moderate H and Cl contents as compared with the 1963 apatite and melt inclusions. Both individual apatite crystals and populations of crystals from each sample are heterogeneous with respect to H, F, and Cl. Such heterogeneities could only be preserved for short periods of time (days to years) in the face of diffusive equilibration. In addition, core to rim volatile variations place relative temporal constraints on the processes affecting volatiles, and allow us to differentiate between monotonic evolution of a single magma batch and processes involving separate components. Using estimated partition coefficients, we can model melt volatile chemistry based on the apatite volatile data. The result of such modeling is that melt inclusions and apatite from the same hand samples yield identical, nonlinear trends in ternary H-F-Cl space, trends that - when combined with the relative timing given by volatile stratigraphy within zoned apatites - are consistent with late stage magma mixing between components with strikingly different volatile chemistry. References 1. Boyce, J.W. and R.L. Hervig, Magmatic degassing histories from apatite volatile stratigraphy. Geology, 2008. 36(1): p. 63. 2. Boyce, J.W. and R.L. Hervig, Apatite as a monitor of late-stage magmatic processes at Volcan Irazu, Costa Rica. Contributions to Mineralogy and Petrology, 2008. 3. Benjamin, E., et al., High water contents in basaltic magmas from Irazu Volcano, Costa Rica. Journal of Volcanology and Geothermal Research, 2007. 168: p. 25.

Boyce, J. W.; Hervig, R. L.

2008-12-01

156

Volatile halocarbons in water  

SciTech Connect

Volatile halocarbons in drinking water have attracted increasing attention during recent years. These substances are also found in body fluids. All disinfectant chemicals used in water treatment seem to produce by-products. Of particular concern are the following substances from the use of various disinfectants according to US EPA: chlorine, bromine and iodine, and chlorine dioxide. The aim of the present study was to follow the formation and occurrence of volatile halocarbons in different types of water.

Kroneld, R.

1986-11-01

157

The implied volatility smirk  

Microsoft Academic Search

This paper provides an industry standard on how to quantify the shape of the implied volatility smirk in the equity index options market. Our local expansion method uses a second-order polynomial to describe the implied volatility–moneyness function and relates the coefficients of the polynomial to the properties of the implied risk-neutral distribution of the equity index return. We present a

Jin E. Zhang; Yi Xiang

2008-01-01

158

One-year observations of carbonaceous and nitrogenous components and major ions in the aerosols from subtropical Okinawa Island, an outflow region of Asian dusts  

NASA Astrophysics Data System (ADS)

Ambient aerosol samples (TSP, n=50), collected at subtropical Okinawa Island, Japan, an outflow region of Asian dusts in the western North Pacific, were studied for organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble total nitrogen (WSTN), water-soluble organic nitrogen (WSON) and major ions to better understand the long-range atmospheric transport and formation and transformation pathways of East Asian aerosols. Concentrations of OC, EC, WSOC, WSTN and WSON ranged from 0.76 to 7.1 ?g m-3 (av. 1.74 ± 1.03 ?g m-3), 0.07-0.96 ?g m-3 (0.28 ± 0.19 ?g m-3), 0.27-1.9 ?g m-3 (0.73 ± 0.38 ?g m-3), 0.77 to 3.03 ?g m-3 (0.58 ± 0.46 ?g m-3) and 0 to 2.2 ?g m-3 (0.12 ± 0.23 ?g m-3), respectively. The average concentration of OC is higher in growing seasons; spring (2.36 ?g m-3) and summer (1.79 ?g m-3). Similarly, the highest concentrations of EC and WSOC were found in spring (av. 0.41 ?g m-3 and 0.95 ?g m-3, respectively) followed by winter (0.37 and 0.90 ?g m-3) whereas the lowest concentrations were found in summer (0.19 and 0.52 ?g m-3, respectively). In contrast, higher concentrations of WSTN were observed in winter (0.86 ?g m-3) and lower concentrations were observed in summer (0.37 ?g m-3) and autumn (0.34 ?g m-3). Similarly, higher concentrations of WSON were observed in early summer (av. 0.26 ?g m-3) due to the emission from marine biota. The high OC/EC (av. 7.6) and WSOC/OC (44%) ratios suggest the secondary formation of organic aerosols. The OC/EC ratios, correlation analyses between OC and EC (r = 0.81), and OC and MSA- (0.81) in spring suggest that springtime aerosols are influenced by additional marine and terrestrial biogenic sources. The correlation analyses of Ca2+ and TSP in spring suggests a significant influence from dust whereas the higher concentrations of NO3- and nss-SO42- in winter suggest the influence from anthropogenic sources including biomass burning, vehicular emission and coal combustion. NH4-N/WSTN ratios peaked in winter (0.56), indicating an important contribution of biomass burning to WSTN in cold season. In contrast, higher NO3-N/WSTN ratio in spring than winter suggests that vehicular emissions are significant in spring. Correlation analyses of major ions suggest that NH4+ and Ca2+ play major role in the neutralization of aerosols forming NH4HSO4, (NH4)2SO4 and CaSO4.

Kunwar, B.; Kawamura, K.

2013-08-01

159

Lunar volatiles: balancing science and resource development  

NASA Astrophysics Data System (ADS)

In the context of human exploration of the moon, the volatiles postulated to exist at the lunar poles have value as resources as well as scientific significance. Once sustained human operations commence on the moon, society will move from a paradigm in which examination of planetary materials has been unconstrained to one where use of those materials will support habitability and further exploration. A framework for the scientific investigation of lunar volatiles that allows for eventual economic exploitation can guide both activities and resolve the conflicts that will inevitably develop if the postulated lunar volatiles prove to be both extant and accessible. Scientific constraints on the framework include characterization at both poles of the isotopes, elements, and molecules in the volatiles, their relative and absolute abundances, and their horizontal and vertical distribution. A subset of this data is necessary in order to assess, develop, and initiate resource exploitation. In addition, the scientific record of volatiles in the cold traps can be contaminated by the cold-trapping of migrating volatiles released from operations elsewhere on the moon even if the indigenous, cold-trapped volatiles are not utilized. Possible decision points defining the transition from science-dominated to exploitation-dominated use include technology limits in the 70K environment, evolving science priorities (funding), and the resolution of major science issues. Inputs to policy development include any North vs. South Pole differences in volatile characteristics and the suitability of the volatiles to enable further scientific exploration of the moon. In the absence of national sovereignty on the moon, enforcement of any framework is an open question, particularly if science and commercial interests are in competition. The framework, processes, and precedent set by how we as a society choose to handle the scientific bounty and resource promise of lunar volatiles may eventually apply to Mars and near-earth asteroids. We believe there are useful lessons to be learned from the terrestrial experience with protected areas such as national parks, wilderness areas, and archeological sites. International agreements such as the Antarctic Treaty (in force since 1961), the Outer Space Treaty (1967), and the Moon Treaty (1979) carry relevant lessons as well.

Crider, Dana

160

Apoptosis-mediated proliferation inhibition of human colon cancer cells by volatile principles of Citrus aurantifolia  

Microsoft Academic Search

Fruits of Citrus aurantifolia were subjected to hydro-distillation using Clevenger type apparatus to obtain volatile oil. Chemical composition of volatile oil was analysed by GC–MS. Twenty-two compounds representing more than 89.5% of the volatile oil were identified. d-limonene (30.13%) and d-dihydrocarvone (30.47%) were found to be the major compounds in the lime volatile oil. This oil showed 78% inhibition of

Jaiprakash R. Patil; G. K. Jayaprakasha; K. N. Chidambara Murthy; Shane E. Tichy; Mahadev B. Chetti; Bhimanagouda S. Patil

2009-01-01

161

Spheroidal confinement of a single electron and of the hydrogen atom, the H 2+ and HeH++ molecular ions with arbitrary nuclear positions along the major axis  

NASA Astrophysics Data System (ADS)

Evidence is given on the usefulness of the variational method to explore the nonseparable Schroedinger problem for the energy evolution of one-electron atoms and diatomic molecular ions confined by a hard prolate spheroidal cavity when the nuclear positions do not coincide with the foci. In this work, we study explicity the case of the hydrogen atom (H) and the H 2+ and HeH++ under the aforementioned confinement conditions and obtain variationally the energy evolution as a function of nuclear positions along the major axis of a confining spheroid of fixed size and eccentricity. The particular case of an electron (e-) under the same confinement conditions is also addressed using the same methodology. Our calculations are restricted to the ground states of H (1s?), HeH++ (1s?), e-(1s?) and the ground-state (1s?g) and first excited state (2p?u) of H 2+. It is shown that a simple LCAO Dickinson-type variational ansatz wavefunction adapted for the confinement case of all systems treated in this work provides very rewarding results for the energy dependence on the size and shape of the confining cavity when compared with corresponding available exact calculations. For e- as well as for H, H 2+ and HeH++ with "on-focus" nuclear positions excellent general quantitative agreement is observed. For the "off-focus" case, moderate quantitative agreement is obtained with available accurate B-spline variational calculations for H. For the molecular systems with "off-focus" nuclear positions, the results of this work are the first of this kind.

Cruz, Salvador A.; Colín-Rodríguez, Ricardo

162

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...

163

VOLATILITY AND IRISH EXPORTS  

Microsoft Academic Search

We analyze the impact of volatility per se on real exports for a small open economy concentrating on Irish trade with the United Kingdom and the United States. An important element is that we take account of the time lag between the trade decision and the actual trade or payments taking place by using a flexible lag approach. Rather than

DON BREDIN; JOHN COTTER

2008-01-01

164

Stochastic volatility, smile & asymptotics  

Microsoft Academic Search

We consider the pricing and hedging problem for options on stocks whose volatility is a random process. Traditional approaches, such as that of Hull and White, have been successful in accounting for the much observed smile curve, and the success of a large class of such models in this respect is guaranteed by a theorem of Renault and Touzi, for

K. Ronnie Sircar; George Papanicolaou

1999-01-01

165

Sealing off volatile emissions  

Microsoft Academic Search

As legislators around the world mandate cuts in the emissions of volatile organic compounds (VOCs), plant operators in the chemical process industries (CPI) are relying on new sealing technology to reduce leaks from valves, flanges, pumps and rotating machines. Such leaks account for over 33% of all the air toxics emitted from refineries and petroleum plants. Improving seals in different

Fouhy

1995-01-01

166

Minimum Tracking Error Volatility  

Microsoft Academic Search

Investors assign part of their funds to asset managers that are given the task of beating a benchmark. The risk management department usually imposes a maximum value of the tracking error volatility (TEV) in order to keep the risk of the portfolio near to that of the selected benchmark. However, risk management does not establish a rule on TEV which

Luca RICCETTI

2010-01-01

167

Output Growth Volatility and Remittances  

Microsoft Academic Search

Output growth volatility has negative effects on growth, poverty and welfare. The empirical literature has therefore searched for country?specific factors affecting volatility and focused on financial development, policy distortions, trade and financial openness. Using the same empirical framework, we focus on migrants' remittances that can help to reduce output growth volatility thanks to their size, stability and low procyclicality. In

MATTEO BUGAMELLI

2011-01-01

168

Lunar Magmatic Volatiles  

NASA Astrophysics Data System (ADS)

Samples returned from the Apollo Missions prompted a variety of experimental investigations (e.g., [1-4]) which form the basis of our current understanding of lunar compositional evolution. The observed low abundances of solidus temperature-suppressing volatiles justified volatile-free experiments. However, the low-pressure nature of the samples makes it unlikely that volatiles were retained during magma ascent and eruption. In an effort to re-assess the lunar mantle volatile budget, we are focusing on the mineral apatite because of its incorporation of F, Cl, and OH as essential structural constituents and its greater ability to retain such volatiles relative to melt. Apatite grains analyzed from magnesian- and alkali-suite rocks (14161,7111, 14161,7269 and 14161,7264), KREEPy impact melt rocks associated with magnesian- and alkali-suite rocks (14161,7233; 14161,7110; 14161,7062; 12033,634-25; SaU 169-4), and mare basalts (79195; 12037,224; 74246; 12023,147,1; 10084; LAP 02205; LAP 03632; NWA 2977) by electron microprobe using the technique of [5,6] show two distinct compositional groups. Apatite from the mare basalts analyzed are primarily mixtures of fluor- "missing component" (OH?) apatite with low Cl abundance, while that from the magnesian- and alkali-suite rocks are fluor-chlor mixtures. Apatite/basaltic melt partition coefficients for F, Cl, and H2O from the data of [7] provide first estimates of magmatic volatile abundances in lunar magmas. They suggest that magmatic water may have been more abundant than F and Cl at the stage of apatite crystallization in mare basalts. In contrast, at this stage, the magmas that produced the Mg-and alkali suite minerals were F- and Cl-dominated. These results have wide-reaching implications regarding the chemical and physical evolution of the Moon and therefore, the next generation of experimental investigations. [1] Walker et al. 1973 EPSL 20, 325-336. [2] Walker et al. 1975 GCA 39, 1219-1235. [3] Longhi 1992 GCA 69, 1275-1286. [4] Longhi 2003 JGR 108, E8, doi:10.1029/2002JE001941. [5] Stormer et al. 1993 Am Min 78, 641. [6] McCubbin et al. 20081st NLSI Conference. [7] Mathez and Webster 2005 GCA 69, 1275-1286.

Nekvasil, H.; McCubbin, F. M.; Lindsley, D. H.

2009-05-01

169

Mechanism of formation of the major estradiol product ions following collisional activation of the molecular anion in a tandem quadrupole mass spectrometer.  

PubMed

The importance of the mass spectral product ion structure is highlighted in quantitative assays, which typically use multiple reaction monitoring (MRM), and in the discovery of novel metabolites. Estradiol is an important sex steroid whose quantitation and metabolite identification using tandem mass spectrometry has been widely employed in numerous clinical studies. Negative electrospray ionization tandem mass spectrometry of estradiol (E2) results in several product ions, including the abundant m/z 183 and 169. Although m/z 183 is one of the most abundant product ions used in many quantitative assays, the structure of m/z 183 has not been rigorously examined. We suggest a structure for m/z 183 and a mechanism of formation consistent with collision induced dissociation (CID) of E2 and several stable isotopes ([D4]-E2, [(13)C6]-E2, and [D1]-E2). An additional product ion from E2, namely m/z 169, has also been examined. MS(3) experiments indicated that both m/z 183 and m/z 169 originate from only E2 [M - H](-) m/z 271. These ions, m/z 183 and m/z 169, were also present in the collision induced decomposition mass spectra of other prominent estrogens, estrone (E1) and estriol (E3), indicating that these two product ions could be used to elucidate the estrogenic origin of novel metabolites. We propose two fragmentation schemes to explain the CID data and suggest a structure of m/z 183 and m/z 169 consistent with several isotopic variants and high resolution mass spectrometric measurements. PMID:23955001

Wooding, Kerry M; Barkley, Robert M; Hankin, Joseph A; Johnson, Christopher A; Bradford, Andrew P; Santoro, Nanette; Murphy, Robert C

2013-08-18

170

Mechanism of Formation of the Major Estradiol Product Ions Following Collisional Activation of the Molecular Anion in a Tandem Quadrupole Mass Spectrometer  

NASA Astrophysics Data System (ADS)

The importance of the mass spectral product ion structure is highlighted in quantitative assays, which typically use multiple reaction monitoring (MRM), and in the discovery of novel metabolites. Estradiol is an important sex steroid whose quantitation and metabolite identification using tandem mass spectrometry has been widely employed in numerous clinical studies. Negative electrospray ionization tandem mass spectrometry of estradiol (E2) results in several product ions, including the abundant m/z 183 and 169. Although m/z 183 is one of the most abundant product ions used in many quantitative assays, the structure of m/z 183 has not been rigorously examined. We suggest a structure for m/z 183 and a mechanism of formation consistent with collision induced dissociation (CID) of E2 and several stable isotopes ([D4]-E2, [13C6]-E2, and [D1]-E2). An additional product ion from E2, namely m/z 169, has also been examined. MS3 experiments indicated that both m/z 183 and m/z 169 originate from only E2 [M - H]- m/z 271. These ions, m/z 183 and m/z 169, were also present in the collision induced decomposition mass spectra of other prominent estrogens, estrone (E1) and estriol (E3), indicating that these two product ions could be used to elucidate the estrogenic origin of novel metabolites. We propose two fragmentation schemes to explain the CID data and suggest a structure of m/z 183 and m/z 169 consistent with several isotopic variants and high resolution mass spectrometric measurements.

Wooding, Kerry M.; Barkley, Robert M.; Hankin, Joseph A.; Johnson, Christopher A.; Bradford, Andrew P.; Santoro, Nanette; Murphy, Robert C.

2013-10-01

171

Mechanism of Formation of the Major Estradiol Product Ions Following Collisional Activation of the Molecular Anion in a Tandem Quadrupole Mass Spectrometer  

NASA Astrophysics Data System (ADS)

The importance of the mass spectral product ion structure is highlighted in quantitative assays, which typically use multiple reaction monitoring (MRM), and in the discovery of novel metabolites. Estradiol is an important sex steroid whose quantitation and metabolite identification using tandem mass spectrometry has been widely employed in numerous clinical studies. Negative electrospray ionization tandem mass spectrometry of estradiol (E2) results in several product ions, including the abundant m/z 183 and 169. Although m/z 183 is one of the most abundant product ions used in many quantitative assays, the structure of m/z 183 has not been rigorously examined. We suggest a structure for m/z 183 and a mechanism of formation consistent with collision induced dissociation (CID) of E2 and several stable isotopes ([D4]-E2, [13C6]-E2, and [D1]-E2). An additional product ion from E2, namely m/z 169, has also been examined. MS3 experiments indicated that both m/z 183 and m/z 169 originate from only E2 [M - H]- m/z 271. These ions, m/z 183 and m/z 169, were also present in the collision induced decomposition mass spectra of other prominent estrogens, estrone (E1) and estriol (E3), indicating that these two product ions could be used to elucidate the estrogenic origin of novel metabolites. We propose two fragmentation schemes to explain the CID data and suggest a structure of m/z 183 and m/z 169 consistent with several isotopic variants and high resolution mass spectrometric measurements.

Wooding, Kerry M.; Barkley, Robert M.; Hankin, Joseph A.; Johnson, Christopher A.; Bradford, Andrew P.; Santoro, Nanette; Murphy, Robert C.

2013-08-01

172

Analysis of volatile organic compounds from illicit cocaine samples  

SciTech Connect

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.

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

1994-07-01

173

Herbivore induced plant volatiles  

PubMed Central

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.

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

2011-01-01

174

Major depression  

MedlinePLUS

Depression - major; Unipolar depression; Major depressive disorder ... The exact cause of depression is not known. Many researchers believe it is caused by chemical changes in the brain. This may be due to ...

175

Are Islamic Indexes more Volatile than Conventional Indexes? Evidence from Dow Jones Indexes  

Microsoft Academic Search

We examine whether global or local events are important drivers in causing major shifts and excessive volatility in Islamic indexes than in conventional indexes. We apply an iterative cumulative sum of squares (ICSS) algorithm to identify structural breaks in the volatility of several major Dow Jones Islamic and conventional indexes over the period 1996-2009. The results show that both indexes

Amélie Charles; Olivier Darné; Adrian Pop

2012-01-01

176

Realized Stock Volatility  

Microsoft Academic Search

Using intradaily high-frequency returns on the Dow Jones Industrial Average portfolio over the January 1993 to May 1996 period we document the properties of interdaily 'realized' volatility and fit a fractionally integrated model that accounts for the leverage effect directly to logarithmic realized variances On the basis of ex ante one-day-ahead prediction criteria we find that this model yields unbiased

Heiko Ebens

1999-01-01

177

Volatility and Underwriting Cycles  

Microsoft Academic Search

\\u000a This paper describes and illustrates the main ideas and findings of research on the volatility and cyclical behavior of insurance\\u000a prices relative to those predicted by a perfectly competitive market in long-run equilibrium. After presenting evidence that\\u000a insurance market prices indeed follow a second order autoregressive process, we examine several lines of research that have\\u000a tried to explain the cyclical

Scott E. Harrington; Greg Niehaus

178

Volatile Nitrosamines in Food  

Microsoft Academic Search

The results of the systematic survey of food from the German market in regard to the occurrence of volatile nitrosamines are presented. The average daily intake for male persons amount to 1.1 ?g for N-nitroso-dimethylamine (NDMA) and 0.1-0.15 ?g for N-nitroso-pyrrolidine (NPYR). About 64% of this total daily intake for NDMA is found in beer, 10% result from cured meat

B. Spiegelhalder; G. Eisenbrand; R. Preussmann

1980-01-01

179

Quorum-sensing quenching by rhizobacterial volatiles.  

PubMed

We show that volatile organic compounds (VOCs) produced by rhizospheric strains Pseudomonas fluorescens B-4117 and Serratia plymuthica IC1270 may act as inhibitors of the cell-cell communication quorum-sensing (QS) network mediated by N-acyl homoserine lactone (AHL) signal molecules produced by various bacteria, including strains of Agrobacterium, Chromobacterium, Pectobacterium and Pseudomonas. This quorum-quenching effect was observed when AHL-producing bacteria were treated with VOCs emitted by strains B-4117 and IC1270 or with dimethyl disulfide (DMDS), the major volatile produced by strain IC1270. LC-MS/MS analysis revealed that treatment of strains Pseudomonas chlororaphis 449, Pseudomonas aeruginosa PAO1 or Ps.?fluorescens 2-79 with VOCs emitted by strain IC1270 or DMDS drastically decreases the amount of AHLs produced by these bacteria. Volatile organic compounds produced by Ps.?chlororaphis 449 were able to suppress its own QS-induction activity, suggesting a negative interaction between VOCs and AHL molecules in the same strain. Quantitative RT-PCR analysis showed that treatment of Ps.?chlororaphis 449 with VOCs emitted by cells of IC1270, B-4117 or 449 itself, or with DMDS, leads to significant suppression of transcription of AHL synthase genes phzI and csaI. Thus, along with AHLs, bacterial volatiles might be considered another type of signal molecule involved in microbial communication in the rhizosphere. PMID:23761359

Chernin, Leonid; Toklikishvili, Natela; Ovadis, Marianna; Kim, Sofia; Ben-Ari, Julius; Khmel, Inessa; Vainstein, Alexander

2011-10-26

180

biogenic aerosol precursors: volatile amines from agriculture  

NASA Astrophysics Data System (ADS)

Information on the occurrence of volatile biogenic amines in the atmosphere is marginal. This group of N-bearing organic compounds are assumed to be a small, though significant component of the atmospheric N-cycle, but are not accounted for in global assessments due to the scarceness of available data. There is increasing evidence for an important role of biogenic amines in the formation of new particulate matter, as well as for aerosol secondary growth. Volatile amines are ubiquitously formed by biodegradation of organic matter, and agriculture is assumed to dominantly contribute to their atmospheric burden. Here we show that the mixing ratios of volatile amines within livestock buildings scale about 2 orders of magnitude lower than NH3, confirming the few literature data available (e.g., Schade and Crutzen, J. Atm. Chem. 22, 319-346, 1995). Flux measurements after manure application in the field, mixing ratios in the headspace of manure storage pools, and concentrations in distilled manure all indicate major depletion of amines relative to NH3 during manure processing. We conclude that the agricultural source distribution of NH3 and amines is not similar. While for NH3 the spreading of manure in the field dominates agricultural emissions, the direct release from livestock buildings dominates the budget of volatile biogenic amines.

Kuhn, Uwe; Sintermann, Jörg; Spirig, Christoph; Ammann, Christof; Neftel, Albrecht

2010-05-01

181

PERTURBATION OF VOLTAGE-SENSITIVE Ca2+ CHANNEL FUNCTION BY VOLATILE ORGANIC SOLVENTS.  

EPA Science Inventory

The mechanisms underlying the acute neurophysiological and behavioral effects of volatile organic compounds (VOCs) remain to be elucidated. However, the function of neuronal ion channels is perturbed by VOCs. The present study examined effects of toluene (TOL), trichloroethylene ...

182

VOLATILE ORGANIC COMPOUNDS INHIBIT HUMAN AND RAT NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS EXPRESSED IN XENOPUS OOCYTES.  

EPA Science Inventory

This manuscript provides evidence to indicate that rats and humans are equally sensitive at the pharmacodynamic level to effects of volatile organic compounds. ? This manuscript also presents novel data that provides a plausible mechanism, disruption of ion channel functi...

183

Volatility of secondary organic aerosol during OH radical induced ageing  

NASA Astrophysics Data System (ADS)

The aim of this study was to investigate oxidation of SOA formed from ozonolysis of ?-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of KIT in Karlsruhe and at the SAPHIR chamber of FZJ in Jülich. A fresh SOA was produced from ozonolysis of ?-pinene or limonene and then aged by enhanced OH exposure. As an OH-radical source in the AIDA-chamber the ozonolysis of tetramethylethylene (TME) was used while in the SAPHIR-chamber the OH was produced by natural light photochemistry. A general feature is that SOA produced from ozonolysis of ?-pinene and limonene initially were rather volatile and becomes less volatile with time in the ozonolysis part of the experiment. Inducing OH chemistry or adding a new portion of precursors made the SOA more volatile due to addition of new semi-volatile material to the aged aerosol. The effect of OH chemistry was less pronounced in high concentration and low temperature experiments when lower relative amounts of semi-volatile material were available in the gas phase. Conclusions drawn from the changes in volatility were confirmed by comparison with the measured and modelled chemical composition of the aerosol phase. Three quantified products from the ?-pinene oxidation; pinonic acid, pinic acid and methylbutanetricarboxylic acid (MBTCA) were used to probe the processes influencing aerosol volatility. A major conclusion from the work is that the OH induced ageing can be attributed to gas phase oxidation of products produced in the primary SOA formation process and that there was no indication on significant bulk or surface reactions. The presented results, thus, strongly emphasise the importance of gas phase oxidation of semi- or intermediate-volatile organic compounds (SVOC and IVOC) for atmospheric aerosol ageing processing.

Salo, K.; Hallquist, M.; Jonsson, Å. M.; Saathoff, H.; Naumann, K.-H.; Spindler, C.; Tillmann, R.; Fuchs, H.; Bohn, B.; Rubach, F.; Mentel, Th. F.; Müller, L.; Reinnig, M.; Hoffmann, T.; Donahue, N. M.

2011-07-01

184

Volatility of secondary organic aerosol during OH radical induced ageing  

NASA Astrophysics Data System (ADS)

The aim of this study was to investigate oxidation of SOA formed from ozonolysis of ?-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of Karlsruhe Institute of Technology (KIT) in Karlsruhe and at the SAPHIR chamber of Forchungzentrum Jülich (FZJ) in Jülich. A fresh SOA was produced from ozonolysis of ?-pinene or limonene and then aged by enhanced OH exposure. As an OH radical source in the AIDA-chamber the ozonolysis of tetramethylethylene (TME) was used while in the SAPHIR-chamber the OH was produced by natural light photochemistry. A general feature is that SOA produced from ozonolysis of ?-pinene and limonene initially was rather volatile and becomes less volatile with time in the ozonolysis part of the experiment. Inducing OH chemistry or adding a new portion of precursors made the SOA more volatile due to addition of new semi-volatile material to the aged aerosol. The effect of OH chemistry was less pronounced in high concentration and low temperature experiments when lower relative amounts of semi-volatile material were available in the gas phase. Conclusions drawn from the changes in volatility were confirmed by comparison with the measured and modelled chemical composition of the aerosol phase. Three quantified products from the ?-pinene oxidation; pinonic acid, pinic acid and methylbutanetricarboxylic acid (MBTCA) were used to probe the processes influencing aerosol volatility. A major conclusion from the work is that the OH induced ageing can be attributed to gas phase oxidation of products produced in the primary SOA formation process and that there was no indication on significant bulk or surface reactions. The presented results, thus, strongly emphasise the importance of gas phase oxidation of semi- or intermediate-volatile organic compounds (SVOC and IVOC) for atmospheric aerosol ageing.

Salo, K.; Hallquist, M.; Jonsson, Å. M.; Saathoff, H.; Naumann, K.-H.; Spindler, C.; Tillmann, R.; Fuchs, H.; Bohn, B.; Rubach, F.; Mentel, Th. F.; Müller, L.; Reinnig, M.; Hoffmann, T.; Donahue, N. M.

2011-11-01

185

ANALYSIS OF VOLATILES AND SEMIVOLATILES BY DIRECT AQUEOUS INJECTION  

EPA Science Inventory

Direct aqueous injection analysis (DAI) with gas chromatographic separation and ion trap mass spectral detection was used to analyze aqueous samples for g/L levels of 54 volatile and semivolatile compounds, and problematic non-purgeables and non-extractables. The method reduces ...

186

Quantitative measurement of delta 9-tetrahydrocannabinol and two major metabolites in physiological specimens using capillary column gas chromatography negative ion chemical ionization mass spectrometry.  

PubMed

delta 9-Tetrahydrocannabinol and two of its metabolites, 11-hydroxy-delta 9-tetrahydrocannabinol and 11-nor-9-carboxy-delta 9-tetrahydrocannabinol, can be measured in a single 1-ml sample of blood, plasma, or urine by a new assay which combines a relatively rapid extraction procedure with capillary column gas chromatography and negative ion chemical ionization mass spectrometry. Deuterium-labeled analogs of each cannabinoid are added to the physiological specimen as internal standards. Two extracts are obtained from each sample: a neutral fraction containing delta 9-tetrahydrocannabinol and 11-hydroxy-delta 9-tetrahydrocannabinol, and an acid fraction containing 11-nor-9-carboxy-delta 9-tetrahydrocannabinol. The neutral fraction is derivatized by treatment with trifluoroacetic anhydride; the acid fraction is first treated with BF3-methanol followed by reaction with trifluoroacetic anhydride. Under electron-capture chemical ionization conditions the derivatized delta 9-tetrahydrocannabinol and 11-nor-9-carboxy-delta 9-tetrahydrocannabinol give abundant molecular anions ideally suited for selected ion monitoring. The negative ion chemical ionization spectrum of the HO-THC-trifluoroacetate shows no molecular anion. Consequently, quantitation of the hydroxy metabolite is achieved by monitoring a fragment ion formed by loss of CF3CO2 from its molecular anion. The limits of reliable measurement are judged to be 0.1 ng ml-1 for 11-nor-9-carboxy-delta 9-tetrahydrocannabinol, 0.2 ng ml-1 for delta 9-tetrahydrocannabinol and 0.5 ng ml-1 for 11-hydroxy-delta 9-tetrahydrocannabinol. Four examples are given of the application of the assay to the analysis of specimens of medico-legal importance. PMID:6305440

Foltz, R L; McGinnis, K M; Chinn, D M

1983-05-01

187

Headspace sampling and detection of cocaine, MDMA, and marijuana via volatile markers in the presence of potential interferences by solid phase microextraction–ion mobility spectrometry (SPME-IMS)  

Microsoft Academic Search

The successful air sampling and detection of cocaine, methylenedioxymethylamphetamine (MDMA), and marijuana using SPME-IMS\\u000a achieved by targeting their volatile markers (methyl benzoate, piperonal, and terpenes, respectively) is presented. Conventional\\u000a methods of direct air sampling for drugs are ineffective because the parent compounds of these drugs have very low vapor pressures,\\u000a making them unavailable for headspace sampling. Instead of targeting the

Hanh Lai; Inge Corbin; José R. Almirall

2008-01-01

188

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)

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.

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

2010-12-01

189

Volatilization of Mercury By Bacteria  

PubMed Central

Volatilization of mercury has been observed from various biological media (tissue homogenates, infusion broth, plasma, urine) containing mercuric chloride. That micro-organisms were responsible was indicated by the finding that the rates of volatilization were highly variable, that a latent period often preceded volatilization, that toluene inhibited the process, and that the capacity to volatilize mercury could be transferred from one biological medium to another. Two species of bacteria when isolated and cultured from these homogenates were able to volatilize mercury. Two other bacteria, one of which was isolated from the local water supply, were also highly active. The volatile mercury was identified as mercury vapour. The importance of these findings in relation to the storage of urine samples prior to mercury analysis is discussed.

Magos, L.; Tuffery, A. A.; Clarkson, T. W.

1964-01-01

190

Two Contrasting Volatile Element Compositions in Primary Melt Inclusions From Mount Shasta  

NASA Astrophysics Data System (ADS)

In order to get the pre-eruptive volatile contents of Mount Shasta lavas, we selected primary melt inclusions from samples 85-38 (high alumina olivine tholeite, HAOT), 85-47, 85-1a and 95-15 (basaltic andesites, BA; Baker et al., 1994, CMP; Grove et al., 2002, CMP). We analyzed the H2O, CO2, F, Cl and S contents from olivine-hosted (Fo86-91) primitive melt inclusions (SiO2 <50 wt% and MgO >8 wt%) using the CAMECA 1280 ion probe of WHOI (MA, USA) and a broad range of standard compositions. As the melt inclusions were partially crystallized, they were experimentally heated in order to melt the daughter minerals. A preliminary study show that our heating procedure did not create any significant loss in the CO2, F, Cl, and S content of the melt inclusions and may not even result in a partial loss of the H2O content of the melt inclusions. The major element compositions of the Shasta melt inclusions fall on a continuous extension of the trend defined by the whole rocks and represent a more primitive endmember. Regarding the volatile contents, they can be divided into two groups: HAOT melt inclusions have low and clustered volatiles compositions (H2O: ~0.04 wt%; F: ~120 ppm; Cl: ~30 ppm; CO2: 250-450 ppm and S: 800- 1100 ppm), similar to primitive MORB compositions, whereas BA melt inclusions show higher and more variable volatile compositions (H2O: 0.1-2.6 wt%; CO2: 70-840, F: 120-1180 ppm; Cl: 480-1230 ppm and S: 480-4600 ppm). They are enriched in volatile elements compared to the primitive MORB compositions. Moreover, the BA melt inclusions are enriched in mobile elements such as K, Ba and B. The results suggest that HAOT melt inclusions and more enriched BA melt inclusions represent two endmembers of a mixing process between a depleted mantle melt and a slab-derived fluid component. The variations in the BA volatiles compositions can indicate an addition of various amounts of aqueous fluid into the mantle source, at different stage of the lavas formation. The division of the melt inclusions into two groups, a dry one (HAOT melt inclusions) and a wet one (BA melt inclusions), is in good agreement with the previous results on the formation of the Mount Shasta lavas.

Le Voyer, M.; Rose-Koga, E. F.; Shimizu, N.; Grove, T. L.; Schiano, P.

2008-12-01

191

Exploring Metropolitan Housing Price Volatility  

Microsoft Academic Search

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

Norman G. Miller; Liang Peng

2003-01-01

192

Exploring Metropolitan Housing Price Volatility  

Microsoft Academic Search

This paper uses GARCH models and a panel VAR model to analyze possible time variation of the volatility of single-family home\\u000a value appreciation and the interactions between the volatility and the economy, using a large quarterly data set that covers\\u000a 277 MSAs in the U.S. from 1990:1 to 2002:2. We find evidence of time varying volatility in about 17% of

Norman Miller; Liang Peng

2006-01-01

193

Volatile analysis of ground almonds contaminated with naturally occurring fungi.  

PubMed

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

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

2011-05-06

194

Reduced Heart Rate Volatility  

PubMed Central

Objective: To determine if using dense data capture to measure heart rate volatility (standard deviation) measured in 5-minute intervals predicts death. Background: Fundamental approaches to assessing vital signs in the critically ill have changed little since the early 1900s. Our prior work in this area has demonstrated the utility of densely sampled data and, in particular, heart rate volatility over the entire patient stay, for predicting death and prolonged ventilation. Methods: Approximately 120 million heart rate data points were prospectively collected and archived from 1316 trauma ICU patients over 30 months. Data were sampled every 1 to 4 seconds, stored in a relational database, linked to outcome data, and de-identified. HR standard deviation was continuously computed over 5-minute intervals (CVRD, cardiac volatility–related dysfunction). Logistic regression models incorporating age and injury severity score were developed on a test set of patients (N = 923), and prospectively analyzed in a distinct validation set (N = 393) for the first 24 hours of ICU data. Results: Distribution of CVRD varied by survival in the test set. Prospective evaluation of the model in the validation set gave an area in the receiver operating curve of 0.81 with a sensitivity and specificity of 70.1 and 80.0, respectively. CVRD predict death as early as 24 hours in the validation set. Conclusions: CVRD identifies a subgroup of patients with a high probability of dying. Death is predicted within first 24 hours of stay. We hypothesize CVRD is a surrogate for autonomic nervous system dysfunction.

Grogan, Eric L.; Morris, John A.; Norris, Patrick R.; France, Daniel J.; Ozdas, Asli; Stiles, Renee A.; Harris, Paul A.; Dawant, Benoit M.; Speroff, Theodore

2004-01-01

195

Classification of Volatile Engine Particles  

SciTech Connect

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.

Cheng, Mengdawn [ORNL

2013-01-01

196

Determination of volatile compounds in cider spirits by gas chromatography with direct injection.  

PubMed

Two analytical methods based on gas chromatography with direct injection are described for the quantitative analysis of volatile compounds (acetals, aldehydes, esters, alcohols, and volatile phenols) in cider brandies. Analytes were divided into major, 15, and minor volatile, 24, compounds depending on their usual concentration in samples. Parameters usually tested for method validation are evaluated. Correlation coefficients are calculated to estimate linearity, obtaining values higher than 0.999. Detection limits range between 0.325 mg/L (1-propanol) and 1.663 mg/L (methanol) among the major volatile compounds and between 0.086 mg/L (ethyl 2-methylbutyrate) and 0.332 mg/L (ethyl tetradecanoate) among the minor volatiles. Mean recoveries ranged between 109% (ethyl lactate) and 95% (1-butanol) for major volatiles and between 109% (1-octen-3-ol) and 94% (ethyl 2-methylbutyrate) for minor volatiles, thus confirming the accuracy of both methods. Reproducibility for major volatiles is < 5.4% (furfural) in all cases and < 9.6% (hexyl acetate) for minor volatiles. Moreover, the accuracy of the methods is evaluated by analyzing a certified whisky and five samples from interlaboratory assays, generally obtaining results in accordance with previous values. PMID:17725870

Rodríguez Madrera, Roberto; Suárez Valles, Belén

2007-08-01

197

Metabolism of stanozolol: Chemical synthesis and identification of a major canine urinary metabolite by liquid chromatography–electrospray ionisation ion trap mass spectrometry  

Microsoft Academic Search

The canine phase I and phase II metabolism of the synthetic anabolic-androgenic steroid stanozolol was investigated following intramuscular injection into a male greyhound. The major phase I biotransformation was hydroxylation to give 6?-hydroxystanozolol which was excreted as a glucuronide conjugate and was identified by comparison with synthetically derived reference materials. An analytical procedure was developed for the detection of this

Rhiannon T. Stewart; Andrew R. McKinney; Carmel M. Kerwick; E. Bruce Young; Andrew Vadasz; Ian A. Cade; Anthony C. Willis; Malcolm D. McLeod

2009-01-01

198

Volatile signals during pregnancy.  

PubMed

Scents play a key role in mediating reproductive interactions in many vertebrates including mammals. Nowadays, several studies indicate that humans seem to use remarkably olfactory communication and are even able to produce and perceive pheromones. Furthermore, over the past several years, it became increasingly clear that pheromone-like chemical signals probably play a role in offspring identification and mother recognition. Recently developed technical procedures (solid-phase microextraction and dynamic headspace extraction) now allow investigators to characterize volatile compounds with high reliability. We analyzed the volatile compounds in sweat patch samples collected from the para-axillary and nipple-areola regions of women during pregnancy and after childbirth. We hypothesized that, at the time of birth and during the first weeks of life, the distinctive olfactory pattern of the para-axillary area is probably useful to newborn babies for recognizing and distinguishing their own mother, whereas the characteristic pattern of the nipple-areola region is probably useful as a guide to nourishment. PMID:20831951

Vaglio, Stefano

2010-01-01

199

Major Programs  

Cancer.gov

The Division of Cancer Prevention supports major scientific collaborations and research networks at more than100 sites across the United States; investigator-initiated grants; postdoctoral training; and specialized resources for researchers.

200

Varietal and processing effects on the volatile profile of Australian olive oils  

Microsoft Academic Search

The volatile profile of virgin olive oils was established using SPME and gas chromatography(-mass spectrometry). The major volatile in approximately 50% of the oils was E-hex-2-enal in contrast with European oils. The minor contribution of C5 compounds to the volatile profiles also contrasted with data on European oils. Hierarchical Cluster Analysis (HCA) implicates variety as the single-most important factor in

Debora Tura; Paul D. Prenzler; Danny R. Bedgood; Michael Antolovich; Kevin Robards

2004-01-01

201

Volatile constituents of dog ( Canis familiaris ) and coyote ( Canis latrans ) anal sacs  

Microsoft Academic Search

The volatile organic compounds from the anal sac secretions of male and female dogs and coyotes were examined using gas chromatography and gas chromatography-mass spectrometry. Short chain (C2–C6) acids and trimethylamine were major constituents. Changes in the type and abundance of the volatiles were examined across state of estrus, species, and gender. No consistent difference in the pattern of volatiles

George Preti; Earl L. Muetterties; Joseph M. Furman; James J. Kennelly; Bradford E. Johns

1976-01-01

202

A simple and sensitive LC-ESI-MS (ion trap) method for the determination of bupropion and its major metabolite, hydroxybupropion in rat plasma and brain microdialysates.  

PubMed

A specific and highly sensitive liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) method for the direct determination of bupropion (BUP) and its main metabolite hydroxybupropion (HBUP) in rat plasma and brain microdialysate has been developed and validated. The analysis was performed on a Bonus RP C18 (100 mm × 2.1mm i.d., 3.5 ?m particles) column using gradient elution with the mobile phase consisting of acetonitrile and ammonium formate buffer (10mM, pH 4). Plasma samples were analyzed after a simple, one-step protein precipitation clean-up with trichloroacetic acid (TCA), however clean-up for microdialysis samples was not necessary, enabling direct injection of the samples into the LC-ESI-MS system. Signals of the compounds were monitored under the multiple reaction monitoring (MRM) mode of the LC-ESI-MS (ion trap) for quantification. The precursor to product ion transitions of m/z 240-184 and m/z 256-238 were used to measure BUP and HBUP, respectively. The method was validated in both plasma and microdialysate samples, and the obtained lower limit of quantification (LLOQ) was 1.5 ng mL(-1) for BUP and HBUP in both matrices. The intra- and inter-day assay variability was less than 15% for both analytes. This LC-ESI-MS method provided simple sampling, rapid clean-up and short analysis time (<9 min), applicable to the routine therapeutic monitoring and pharmacokinetic studies of BUP and HBUP. PMID:21315892

Yeniceli, Duygu; Sener, Erol; Korkmaz, Orhan Tansel; Do?rukol-Ak, Dilek; Tuncel, Ne?e

2010-12-21

203

Expected stock returns and volatility  

Microsoft Academic Search

This paper examines the relation between stock returns and stock market volatility. We find evidence that the expected market risk premium (the expected return on a stock portfolio minus the Treasury bill yield) is positively related to the predictable volatility of stock returns. There is also evidence that unexpected stock market returns are negatively related to the unexpected change in

Kenneth R. French; G. William Schwert; Robert F. Stambaugh

1987-01-01

204

Chirospecific analysis of plant volatiles  

Microsoft Academic Search

Characteristic features of the analysis of plant volatiles by enantioselective gas (gas-liquid) chromatography and gas chromatography\\/mass spectrometry are discussed. The most recent advances in the design of enantioselective stationary phases are surveyed. Examples of the preparation of the most efficient phases based on modified cyclodextrins are given. Current knowledge on the successful analytical resolution of different types of plant volatiles

A. V. Tkachev

2007-01-01

205

Volatility, risk modeling and utility  

Microsoft Academic Search

This article develops the foundations for several new models of risk and volatility. Methods used include utility analysis and mathematical psychology. Risk and volatility can be modeled as aggregations of preferences of market participants, and or optimization problems. Market risk assessment is a multi-criteria process that typically requires information processing, and thus cannot be defined accurately by rigid quantitative models.

Michael Nwogugu

2006-01-01

206

Dynamics of implied volatility surfaces  

Microsoft Academic Search

The prices of index options at a given date are usually represented via the corresponding implied volatility surface, presenting skew\\/smile features and term structure which several models have attempted to reproduce. However, the implied volatility surface also changes dynamically over time in a way that is not taken into account by current modelling approaches, giving rise to `Vega' risk in

Rama Cont; José da Fonseca

2002-01-01

207

VOLATILIZATION OF ORGANIC POLLUTANTS FROM WATER  

EPA Science Inventory

The volatilization of organic environmental contaminants from water bodies to the atmosphere was investigated. The general aim was to elucidate the factors that control the volatilization process and develop predictive methods for calculating volatilization rates for various comp...

208

Cometary Volatiles and Origins  

NASA Astrophysics Data System (ADS)

H2O, CO2, and CO are the three most abundant, inorganic cometary volatiles in nearly all comets. The relative abundances of these three species, in the still small sample of comets for which they have been measured, suggest the abundances are not controlled by thermal evolution but rather are primordial. If so, the snow lines in models of the protoplanetary disk suggest that the both Jupiter-family comets (JFCs) and Long-period comets (LPCs) formed in overlapping regions, probably mostly between present-day Jupiter and Uranus, but with the JFCs extending closer to the proto-sun and the LPCs extending further from the protosun. This then requires that JFCs be transported via planetary migration to the scattered disk , as has been argued by dynamicists for several years.

A'Hearn, Michael F.; Feaga, L. M.; Ad Hoc Cometary Team

2012-10-01

209

Transformations of snow chemistry in the boreal forest: Accumulation and volatilization  

USGS Publications Warehouse

This paper examines the processes and dynamics of ecologically-important inorganic chemical (primarily NO3-N) accumulation and loss in boreal forest snow during the cold winter period at a northern and southern location in the boreal forest of western Canada. Field observations from Inuvik, Northwest Territories and Waskesiu, Saskatchewan, Canada were used to link chemical transformations and physical processes in boreal forest snow. Data on the disposition and overwinter transformation of snow water equivalent, NO3-, SO42- and other major ions were examined. No evidence of enhanced dry deposition of chemical species to intercepted snow was found at either site except where high atmospheric aerosol concentrations prevailed. At Inuvik, concentrations of SO42- and Cl- were five to six times higher in intercepted snow than in surface snow away from the trees. SO4-S and Cl loads at Inuvik were correspondingly enhanced three-fold within the nearest 0.5 m to individual tree stems. Measurements of snow affected by canopy interception without rapid sublimation provided no evidence of ion volatilization from intercepted snow. Where intercepted snow sublimation rates were significant, ion loads in sub-canopy snow suggested that NO3- volatized with an efficiency of about 62% per snow mass sublimated. Extrapolating this measurement from Waskesiu to sublimation losses observed in other southern boreal environments suggests that 19-25% of snow inputs of NO3- can be lost during intercepted snow sublimation. The amount of N lost during sublimation may be large in high-snowfall, high N load southern boreal forests (Quebec) where 0.42 kg NO3-N ha-1 is estimated as a possible seasonal NO3- volatilization. The sensitivity of the N fluxes to climate and forest canopy variation and implications of the winter N losses for N budgets in the boreal forest are discussed.This paper examines the processes and dynamics of ecologically-important inorganic chemical (primarily NO3-N) accumulation and loss in boreal forest snow during the cold winter period at a northern and southern location in the boreal forest of western Canada. Field observations from Inuvik. Northwest Territories and Waskesiu, Saskatchewan, Canada were used to link chemical transformations and physical processes in boreal forest snow. Data on the disposition and overwinter transformation of snow water equivalent, NO3-, SO42- and other major ions were examined. No evidence of enhanced dry deposition of chemical species to intercepted snow was found at either site except where high atmospheric aerosol concentrations prevailed. At Inuvik, concentrations of SO42- and Cl- were five to six times higher in intercepted snow than in surface snow away from the trees. SO4-S and Cl loads at Inuvik were correspondingly enhanced three-fold within the nearest 0.5 m to individual tree stems. Measurements of snow affected by canopy interception without rapid sublimation provided no evidence of ion volatilization from intercepted snow. Where intercepted snow sublimation rates were significant, ion loads in sub-canopy snow suggested that NO3- volatized with an efficiency of about 62% per snow mass sublimated. Extrapolating this measurement from Waskesiu to sublimation losses observed in other southern boreal environments suggests that 19-25% of snow inputs of NO3- can be lost during intercepted snow sublimation. The amount of N lost during sublimation may be large in high-snowfall, high N load southern boreal forests (Quebec) where 0.42 kg NO3-N ha-1 is estimated as a possible seasonal NO3- volatilization. The sensitivity of the N fluxes to climate and forest canopy variation and implications of the winter N losses for N budgets in the boreal forest are discussed.

Pomeroy, J. W.; Davies, T. D.; Jones, H. G.; Marsh, P.; Peters, N. E.; Tranter, M.

1999-01-01

210

First volatile inventory for Gorely volcano, Kamchatka  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

211

A mechanistic model for estimating ammonia volatilization from slurry applied to bare soil  

Microsoft Academic Search

The loss of ammonia by volatilization after slurry application may lead to large losses of soil-plant nitrogen. It is also a major source of atmospheric ammonia. These fluxes must therefore be accurately measured. However, volatilization depends on many features of the soil, climate and slurry, so that it is difficult to predict, or even to interpret and compare data from

S. Génermont; P. Cellier

1997-01-01

212

Modelling financial volatility in the presence of abrupt changes  

NASA Astrophysics Data System (ADS)

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.

Ross, Gordon J.

2013-01-01

213

Arsenic(III, V) adsorption on a goethite-based adsorbent in the presence of major co-existing ions: Modeling competitive adsorption consistent with spectroscopic and molecular evidence  

NASA Astrophysics Data System (ADS)

Adsorption of the two oxyanions, arsenate (As(V)) and arsenite (As(III)), on a common goethite-based granular porous adsorbent is studied in the presence of major co-existing ions in groundwater (i.e., phosphate, silicic acid, sulfate, carbonate, magnesium, and calcium) and predicted using the extended triple layer model (ETLM), a dipole modified single-site triple layer surface complexation model consistent with spectroscopic and molecular evidence. Surface species of all ions were selected according to the previous ETLM studies and published experimental spectroscopic/theoretical molecular information. The adsorption equilibrium constants for all ions were determined using adsorption data obtained in single-solute systems. The adsorption equilibrium constants referenced to the site-occupancy standard state (indicated by K?) were compared with those for goethite in the literature if available. The values of these constants for the goethite-based adsorbent are found to be close to the values for goethite previously studied. These "constrained" adsorption equilibrium constants determined in single-solute systems were used in the ETLM to predict the competitive interactions of As(III, V) with the co-existing ions in binary-solute systems. The ETLM is capable of predicting As(III, V) adsorption in the presence of oxyanions (phosphate, silicic acid, sulfate, and carbonate). This study presents the first successful and systematic prediction of the competitive interactions of As(III, V) with these oxyanions using the ETLM. The ETLM prediction of surface (and aqueous) speciation also provides insights into the distinct adsorption behavior of As(III, V) in the presence of the oxyanions. Magnesium and calcium significantly enhanced As(V) adsorption at higher pH values, while they had little effect on As(III) adsorption. The enhanced adsorption of As(V), however, could not be predicted by the ETLM using the surface species proposed in previous ETLM studies. Further studies are necessary to identify ternary complexes, especially at high pH. Adsorption isotherms of As(V), a dominant form of arsenic in adsorptive water treatment systems, in the presence of the co-existing ions under relevant conditions of water treatment systems are also obtained and predicted by the ETLM to study and compare the effect of the co-existing ions on As(V) removal.

Kanematsu, Masakazu; Young, Thomas M.; Fukushi, Keisuke; Green, Peter G.; Darby, Jeannie L.

2013-04-01

214

Turmeric (Curcuma longa L.) volatile oil inhibits key enzymes linked to type 2 diabetes.  

PubMed

Anti-diabetic capacity of Curcuma longa volatile oil in terms of its ability to inhibit glucosidase activities was evaluated. Turmeric volatile oils inhibited glucosidase enzymes more effectively than the reference standard drug acarbose. Drying of rhizomes was found to enhance ?-glucosidase (IC?? = 1.32-0.38 ?g/ml) and ?-amylase (IC?? = 64.7-34.3 ?g/ml) inhibitory capacities of volatile oils. Ar-Turmerone, the major volatile component in the rhizome also showed potent ?-glucosidase (IC?? = 0.28 ?g) and ?-amylase (IC?? = 24.5 ?g) inhibition. PMID:22385048

Lekshmi, P C; Arimboor, Ranjith; Indulekha, P S; Menon, A Nirmala

2012-03-05

215

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

USGS Publications Warehouse

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.

Fujii, Roger; Swain, W. C.

1995-01-01

216

Analysis of Volatile Organic Compounds.  

National Technical Information Service (NTIS)

An improved system is described for reproducibly analyzing, both qualitatively and quantitatively, trace amounts of a large number of organic volatiles existing in a gas sample. Applications include: (1) analyzing the headspace gas of body fluids and comp...

A. Zlatkis

1974-01-01

217

Assessment of volatile organic compound emissions from ecosystems of China  

Microsoft Academic Search

Isoprene, monoterpene, and other volatile organic compound (VOC) emissions from grasslands, shrublands, forests, and peatlands in China were characterized to estimate their regional magnitudes and to compare these emissions with those from landscapes of North America, Europe, and Africa. Ecological and VOC emission sampling was conducted at 52 sites centered in and around major research stations located in seven different

L. F. Klinger; Q.-J. Li; A. B. Guenther; J. P. Greenberg; B. Baker; J.-H. Bai

2002-01-01

218

The Impact of Exchange Rate Volatility on International Trade Flows  

Microsoft Academic Search

Despite the best efforts of economists, a basic paradox as to the impact of exchange rate volatility on trade flows remains unresolved at both the theoretical and empirical level. This paper surveys the vast literature in the area in an attempt to identify major issues which have contributed to the development of the debate and examine whether any general direction

Michael D. McKenzie

1999-01-01

219

Volatile Constituents of the Leaves of Ocimum sanctum L  

Microsoft Academic Search

Analysis of the volatiles isolated from the leaves of Ocimum sanctum L., Lamiaceae, by capillary GC and GC\\/MS resulted in the identification of 25 components comprising 98.7% of the total oil. Eugenol (53.4%), ?-caryophyllene (31.7%) and ?-elemene (6.2%) were the major components found.

P. M. Raju; Mohamed Ali; Arturo Velasco-Negueruela; María José Pérez-Alonso

1999-01-01

220

High Consumption Volatility: The Impact of Natural Disasters?  

Microsoft Academic Search

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

Philippe Auffret

2003-01-01

221

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

PubMed

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

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

2008-10-01

222

Fruit volatile analysis using an electronic nose.  

PubMed

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

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

2012-03-30

223

Fruit Volatile Analysis Using an Electronic Nose  

PubMed Central

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.

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

2012-01-01

224

Volatile pipe prices ahead  

SciTech Connect

Over the last 10 years, prices for oilfield casing and tubing have shot up and down like a roller coaster. Average pipe prices went up 80 percent in the 1979-81 drilling boom. They dropped 50 percent in the 1982-83 period, only to recover 20 percent in 1984-85. The collapse of crude prices caused another 30 percent drop in 1986. Since they bottomed out in August of that year, prices have come up by 60 percent. The key question: ''What lies ahead.'' The short answer: ''Probably more of the same''. This article looks at what has caused price fluctuations of such magnitude and volatility over the past several years to assess the outlook for 1988 and beyond. The author says we are not on the brink of a severe OCTG shortage of any sort, though there may be some very localized spot shortages in terms of deliverability and price. There is likely to be some build up of tubular inventory among supply houses wary of losing regular customers to those with adequate inventories. The characteristic first-of-the-year dip in the active rig count will supplement a slight inventory building, as will an expected increase in imports. The bottomline impact for the wellsite is there is little chance for substantial price increases until the third or fourth quarter of this year. Even then, a considerable jump in utilization would be needed and most analysts are predicting the rig count to slowly rise to about the 1500-plus range for the fourth quarter.

Perkins, C.

1988-01-01

225

Volatile components of ethanolic extract from broccolini leaves.  

PubMed

Broccolini (Brassica oleracea Italica?×?Alboglabra) is a hybrid of broccoli and kai-lan, Chinese broccoli. To date, no study has been reported on the chemical composition of the volatile fractions of this raw material. In this study, the volatile constituents from the ethanolic extract of broccolini leaves were analysed by gas chromatography-mass spectrometry (GC-MS). Sixteen compounds were identified. The major components include 5-phenyl-undecane (11%), n-hexadecanoic acid (9.34%), octadecanoic acid (6.39%), 1,1,3-trimethyl-3-phenyl-indan (4.0%), 3-(2-phenylethyl)benzonitrile (3.48%) and phytol (3.37%). PMID:21859369

Wang, Xiaoqin; Zhang, Bochao; Wang, Bingfang; Zhang, Xuewu

2011-08-23

226

Volatile organic compound emissions: an inventory for Western Europe  

SciTech Connect

The report gives details of an inventory compiled by CONCAWE and covering man-made non-methane volatile organic compound (VOC) emissions in Western Europe. The survey shows that the major man-made sources are road transport and solvents, each contributing around 40%. Total oil industry operations account for around 8%, with refining operations contribution about 2%. The major oil industry contribution comes from the distribution of gasoline, including vehicle refuelling (5%).

Edwards, A.H.; Campobasso, A.; Camps, R.; Cremer, G.; Long, M.D.

1986-01-01

227

The effect of saline groundwater exchange, evaporation and variable river flows and on stable isotopes (18O and 2H) and major ion concentrations along the Darling River, NSW, Australia  

NASA Astrophysics Data System (ADS)

Australia's longest river, the Darling River, faces extreme pressure from drought and over extraction of water from its catchment. The lack of detailed baseline hydrochemical and isotopic data for the Darling River has prompted research aimed at using hydrological tracers to assess water gains and losses within the Darling River Drainage Basin. This study uses temporal hydrochemical and stable isotope data (18O and 2H) that has been monitored from gauging stations along the Barwon-Darling catchment over a five-year period from 2002 to 2007 as part of the Global Network for Isotopes in Rivers (GNIR) monitoring programme. Stream flow data, monthly ?18O and ?2H values and major ion chemistry is presented. Individual flow events were found to be isotopically distinct but the LELs that develop after these events have a very similar slope indicating similar climatic conditions across this region. During low flow conditions, salt concentrations increase systematically, ?18O and ?2H become enriched and d-excess becomes more negative indicating significant evaporation. Flow events input isotopically depleted fresh waters to the system and the d-excess returns towards the local meteoric water line. The major ions increase in concentration at a greater rate at Louth than they do at upstream at Bourke or downstream at Wilcannia, despite similar decreases in flow rates for all three sites. The hydrological response of the river to drought has had detrimental affects on the surface water system because it provides a pathway for saline groundwater to discharge into the river system.

Meredith, K. T.; Hughes, C. E.; Hollins, S. E.; Cendón, D. I.; Hankin, S.

2009-04-01

228

Polyatomic Ion Bingo  

NSDL National Science Digital Library

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.

Blind, Perkins S.

2012-06-26

229

Quantitative determination of glycopyrrolate in human plasma by liquid chromatography–electrospray ionization mass spectrometry: The use of a volatile ion-pairing agent during both liquid–liquid extraction and liquid chromatography  

Microsoft Academic Search

The work presented here deals with the development of a quantitative tool for the determination of the quaternary ammonium anticholinergic glycopyrrolate in human plasma samples. Mepenzolate was used as an internal standard. The plasma samples were subjected to a suitable sample clean-up consisting of a simple and relatively fast, two step liquid–liquid ion-pair extraction procedure. The chromatography, using the same

M. L. Storme; R. S. t’Kindt; W. Goeteyn; K. Reyntjens; J. F. Van Bocxlaer

2008-01-01

230

Modeling the influence of precursor volatility and molecular structure on secondary organic aerosol formation using evaporated fuel experiments  

NASA Astrophysics Data System (ADS)

We use SOA production data from an ensemble of evaporated fuels to test various SOA formation models. Except for gasoline, traditional SOA models focusing exclusively on volatile species in the fuels under-predict the observed SOA formation. These models can be improved dramatically by accounting for lower volatility species, but at the cost of a large set of free parameters. In contrast, a SOA model based only on the volatility of the precursor, starting with the volatility distribution of the evaporated fuels and optimized for the volatility reduction of first-generation products, reasonably reproduces the observed SOA formation with relatively few free parameters. The exceptions are exotic fuels such as Fischer-Tropsch fuels that expose the central assumption of the volatility based model that most emissions consist of complex mixtures displaying reasonably average behavior. However, for the vast majority of fuels, the volatility based model performs well.

Jathar, S. H.; Donahue, N. M.; Adams, P. J.; Robinson, A. L.

2013-09-01

231

Volatility from copper and tungsten alloys for fusion reactor applications  

SciTech Connect

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.

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

1989-01-01

232

The Relationship Between Molybdenum Oxidation State and Iodine Volatility in Nuclear Fuel  

SciTech Connect

The relationship between molybdenum oxidation state and iodine volatility in nuclear fuel was investigated using high-temperature Knudsen cell-mass spectroscopy. It was observed that the ratio of the intensities of molecular iodine ions I{sub 2}{sup +} and CsI{sup +} in the Knudsen cell-mass spectroscopic experiments can be used to investigate the iodine volatility in fuel under different conditions. The experiments show that the iodine volatility is similar in systems consisting of CsI alone, CsI/UO{sub 2}, and CsI/UO{sub 2}/MoO{sub x} (with molybdenum in oxidation states 0, 2, and 4). The iodine volatility is much higher, however, in CsI/UO{sub 2}/MoO{sub 3} systems (with molybdenum in oxidation state = 6). The iodine volatility in the fuel increases significantly if oxidation of the molybdenum goes to the MoO{sub 3} stage. The increase in the iodine volatility is caused by the formation of elemental iodine from cesium iodide. It is concluded from these measurements that the oxidation of the fuel to the UO{sub 2.2} will substantially increase the volatilization of fission product iodine. An analysis of the literature data suggests that the enhanced iodine volatilization process may be initiated when the fuel is oxidized to UO{sub 2.02}.

Sunder, S. [Atomic Energy of Canada Limited (Canada)

2003-11-15

233

Temperature- and fO2-Dependence of the Volatility and Condensation Behavior of Volatile Elements: Experimental Results  

NASA Astrophysics Data System (ADS)

The volatility of elements is an important aspect in the Earths past, present and future: its present impact is reflected in elemental transport in the daily outgassing of volcanic vents. Its importance for understanding the earth also reaches back to the earliest periods of our solar system: nebular gases and matter underwent elemental fractionation processes based on the differences in the evaporation and condensation behaviour of matter within the solar nebula, which finally resulted in the formation of condensed matter from interplanetary dust particles up to the planets of the solar system. Precise knowledge of parameters controlling volatility as well as condensation of elements is, however, still lacking. The volatile or refractory behaviour of an element or component likely depends on the temperature and oxygen fugacity (fO2) conditions prevailing. To address this issue, a systematic study of the volatility of 18 volatile elements in respect to fO2 and temperature was launched applying a modified mechanically assisted equilibration technique (MAE): 60 g of a haplobasaltic starting composition (An-Di) was doped with up to 5000 ppm of volatile elements (Li, K, Na, Ti, Cr, Mn, Co, Cu, Cu, Zn, Ga, Rb, Cd, In, Sn, Sb, Cs, Tl) and heated to run temperature. For the fO2 dependence 2 experiments at logfO2 = -11.3 (~ IW -0.5) and - 0.7 (pure air) at a constant temperature of 1300 °C were performed, while T dependence was investigated at 1300 and 1500 °C at constant fO2 (pure air). The original MAE technique was modified by two Al2O3 plates extending from the hot spot region up to the upper, cooler regions in the muffle tube furnace, which was T calibrated prior to any experiment. In this way the plates function as condensation traps. Experiments lasted for up two weeks while experimental conditions were kept constant and monitored continuously. Up to 46 samples were taken from the melt by time-series sampling to measure the loss of volatile elements from the melt due to volatility. In the upper, cooler parts of the setup, condensation on the surface of the two Al2O3 plates was observed. In this way both evaporation as well as condensation behaviour of the investigated elements was investigated simultaneously. Quenched samples were investigated by electron microprobe analysis (major elements) and laser-ablation inductively coupled plasma mass spectrometry (LAMS) for their volatile content. The present data indicate a complex behaviour of volatility. 1. Volatile concentrations do not generally decrease for all elements continuously with time as anticipated in previous studies: concentrations of some elements generally assumed to be volatile exhibit very low volatility (independent of fO2: Cs, Rb, Na, K, Li). Some elements become more volatile with increasing fO2 (Cr, Ti, Mn), while others become less volatile (moderately: Cu, Co, Tl, Ga, Zn; dramatically: In, Sn, Sb, Cd). Condensation traps show clear indications (e.g.: differences in colour) for a continuous condensation sequence of components with decreasing T, which will require detailed analysis by LAMS.

Ertel, W.; Dingwell, D. B.

2010-12-01

234

[Allelopathy and chemical constituents of Ligularia virgaurea volatile].  

PubMed

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

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

2005-10-01

235

Temporal Structure of Volatility Fluctuations  

NASA Astrophysics Data System (ADS)

Volatility fluctuations are of great importance for the study of financial markets, and the temporal structure is an essential feature of fluctuations. To explore the temporal structure, we employ a new approach based on the return interval, which is defined as the time interval between two successive volatility values that are above a given threshold. We find that the distribution of the return intervals follows a scaling law over a wide range of thresholds, and over a broad range of sampling intervals. Moreover, this scaling law is universal for stocks of different countries, for commodities, for interest rates, and for currencies. However, further and more detailed analysis of the return intervals shows some systematic deviations from the scaling law. We also demonstrate a significant memory effect in the return intervals time organization. We find that the distribution of return intervals is strongly related to the correlations in the volatility.

Wang, Fengzhong; Yamasaki, Kazuko; Stanley, H. Eugene; Havlin, Shlomo

236

Ion mobility studies of electronically excited states of atomic transition metal cations: Development of an ion mobility source for guided ion beam experiments  

Microsoft Academic Search

The design of an ion mobility source developed to couple to a guided ion beam tandem mass spectrometer is presented. In these\\u000a exploratory studies, metal ions are created continuously by electron ionization of the volatile hexacarbonyls of the three\\u000a group 6 transition metals. These ions are focused into a linear hexapole ion trap, which collects the ions and then creates

Christopher Iceman; Chad Rue; Robert M. Moision; Barun K. Chatterjee; P. B. Armentrout

2007-01-01

237

Chemical composition and antioxidant effect of glycosidically bound volatile compounds from oregano ( Origanum vulgare L. ssp. hirtum)  

Microsoft Academic Search

The present work examines the content and chemical composition of the glycosidically bound volatiles from oregano as well as their antioxidative properties. The glycosidically bound volatiles amounted to 20 mg kg?1 in dried leaves and flowers of oregano. Fourteen volatile aglycones were identified with thymoquinone as the major component. Other important aglycones were benzyl alcohol, eugenol, 2-phenyl-ethanol, thymol, 3-hexen-1-ol and

M Milos; J Mastelic; I Jerkovic

2000-01-01

238

Volatilization of Organic Pollutants from Water.  

National Technical Information Service (NTIS)

The volatilization of organic environmental contaminants from water bodies to the atmosphere was investigated. The general aim was to elucidate the factors that control the volatilization process and develop predictive methods for calculating volatilizati...

A. Bobra D. Mackay E. Chau J. Billington W. Yang Shiu

1982-01-01

239

Studies on the Volatile Compounds in Mushrooms.  

National Technical Information Service (NTIS)

This publication summarizes studies on volatile natural compounds, especially those in fresh mushrooms. Using a combined GLC-MS method, an average of 50 volatile compounds were identified in each of the seven fresh mushrooms Cantharellus cibarius, Gyromit...

H. Pyysalo

1975-01-01

240

Characterisation of bound volatile compounds of a low flavour kiwifruit species: Actinidia eriantha.  

PubMed

Aroma compounds in fruit are known to occur in free and glycosidically bound forms. The bound volatile fraction of a low flavour kiwifruit species, Actinidia eriantha, was studied. The fruit have a bland and grassy flavour. Glycosidic precursors were isolated from juice by adsorption onto an Amberlite XAD-2 column. After enzymatic hydrolysis with Rapidase AR2000, the released aglycones were analysed by GC-MS. Alcohols, terpenoids and phenolics were the most numerously represented compound classes. Alcohols, benzenoids and phenolics showed the highest concentrations. Major compounds were 2-phenylethanol, furfuryl alcohol, (Z)-3-hexen-1-ol, coniferyl alcohol, isoamyl alcohol and linolenic acid. Several of the bound compounds found, including linoleic, linolenic and benzoic acids and coniferyl alcohol, are precursors of odorous volatiles. Many compounds detected as bound volatiles have not been previously reported as free volatiles in A. eriantha. The bound volatile composition of A. eriantha also showed differences with those of other kiwifruit species. PMID:23107675

Garcia, Coralia V; Quek, Siew-Young; Stevenson, Ralph J; Winz, Robert A

2012-03-03

241

Mars' volatile and climate history  

Microsoft Academic Search

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

Bruce M. Jakosky; Roger J. Phillips

2001-01-01

242

Output growth volatility and remittances  

Microsoft Academic Search

Since output growth volatility has negative effects on growth, poverty and welfare, especially in poorer countries, it is crucial to identify the country-specific factors that affect it. The empirical literature has focused mostly on financial development, policy distortions and globalization variables. Among the latter, attention has been directed in particular to trade and financial openness. We contribute to this literature

Matteo Bugamelli

2008-01-01

243

Possible Sources of Polar Volatiles  

NASA Astrophysics Data System (ADS)

Extensive analyses of returned Apollo samples demonstrated that the Moon is extremely volatile poor. While this conclusion remains true, various measurements since the late 90's implicated the presence of water: e.g., enhanced reflection of circularly polarized radar signals and suppression of epithermal neutrons near the poles. More recently, traces of H2O have been discovered inside volcanic glass, along with more significant amounts residing in hydrous minerals (apatite) returned from both highland and mare landing sites. Three recent lunar missions (DIXI, M3, Cassini) identified hydrous phases on/near the lunar surface, whereas the LCROSS probe detected significant quantities of volatiles (OH, H2O and other volatiles) excavated by the Centaur impact. These new mission results and sample studies, however, now allow testing different hypotheses for the generation, trapping, and replenishment of these volatiles. Solar-proton implantation must contribute to the hydrous phases in the lunar regolith in order to account for the observed time-varying abundances and occurrence near the lunar equator. This also cannot be the entire story. The relatively low speed LCROSS-Centaur impact (2.5km/s) could not vaporize such hydrous minerals, yet emissions lines of OH (from the thermal disassociation of H2O), along with other compounds (CO2, NH2) were detected within the first second, before ejecta could reach sunlight. Telescopic observations by Potter and Morgan (1985) discovered a tenuous lunar atmosphere of Na, but the LCROSS UV/Vis spectrometer did not detect the Na-D line until after the ejecta reached sunlight (along with a line pair attributed to Ag). With time, other volatile species emerged (OH, CO). The LAMP instrument on the Lunar Reconnaissance Orbiter had a different viewpoint from the side (rather than from above) and detected many other atomic species release by the LCROSS-Centaur impact. Consequently, it appears that there is a stratigraphy for trapped species: surface layer of atomic/molecules over a regolith containing an assortment of cold-trapped elements (Na/Ca/Mg/K/Ag/Hg) and compounds (OH, CO, H2). In addition to the solar flux, cometary dust dominates the impact flux for particles less than 1g and dominates impact flashes observed telescopically (Cooke, pers. comm.). While large, volatile-rich impactors may be less frequent, they have the potential for injecting significant quantities (10-15%) into impact melts (Harris and Schultz, 2011). In addition, laboratory impact experiments at the NASA Ames Vertical Gun Range used high-speed spectroscopy to illustrate the capture of volatile fractions below the surface during hypervelocity impacts. On the Moon, melt-trapped volatiles comprising the regolith would be gradually recycled during each lunation during impact gardening, thereby titrating the supply of volatiles to the polar deep freeze. Consequently, diverse sources likely contributed this potpourri of trapped cold-trapped volatile

Schultz, P. H.

2011-12-01

244

Volatilizing toxic metals from soil  

SciTech Connect

This study revealed that lead, cadmium, mercury, zinc, arsenic, and selenium can be volatilized from both spiked and actual contaminated soils by heating in inert or reducing atmospheres. Generally oxygen proved to be detrimental to the remediation process. An apparatus capable of rapidly heating soil samples to as high as 1,100 C was designed and built to volatilize toxic inorganic contaminants from 500-mg soil samples while purging with hydrogen, nitrogen, or nitrogen/oxygen mixtures. An average of 93% lead removal was observed for PbSO[sub 4]-, Pb(NO[sub 3])[sub 2]-, PbCO[sub 3]-, Pb[sup 0]-, and PbO-spiked soil samples aged for up to two years with initial lead concentrations of 2,000 mg/kg soil when heated for 20 minutes at 900 C in a flowing stream of hydrogen or nitrogen. About 50% lead removal was achieved at 750 C for all the compounds at these conditions. Similar results were obtained for lead-contaminated soil from a battery waste site. Under the same conditions, a sample containing 8,220 mg Pb/kg soil yielded 93% lead removal in hydrogen or nitrogen, but only 73% lead removal in air. Other toxic metals and metalloids also proved amenable to removal from soil by volatilization. The temperatures required for approximately 90% removal during 10 minutes heating in nitrogen were as follows: mercury 370 C, cadmium 550 C, zinc 850 C, arsenic 500 C, and selenium 700 C. Further experiments with oxygen added to the purge gas showed that as little as 1% oxygen significantly lowered the removal of metals, particularly at the lower volatilization temperatures. These experimental results are encouraging; they suggest that the controlled-temperature-metal-volatilization technique is potentially applicable for the permanent lean up of metal contaminated soil.

Clifford, D.A.; Shensin Chen; Reznik, C. (Univ. of Houston, TX (United States). Dept. of Civil and Environmental Engineering)

1993-01-01

245

Volatile Loss from Melt Inclusions in Clasts of Differing Sizes  

NASA Astrophysics Data System (ADS)

The volatile concentrations in olivine-hosted melt inclusions are vulnerable to many processes that occur from magma chamber to eruption. Recent laboratory experiments show that melt inclusions can requilibrate with surrounding magma through their host olivine on the order of days [1]. Mantle xenolith studies find evidence for diffusion of water though olivine during ascent on the timescale of hours [2]. This study focuses on the final process that affects volatile concentrations in melt inclusions: re-equilibration during post-eruptive degassing and cooling. We exploit the differing cooling rates experienced by tephra clasts to constrain the potential loss of volatiles over timescales of minutes. We chose for study a sample suite of varying tephra sizes that was collected in situ during a single day (October 17, 1974) of the sub-plinian eruption of Volcán de Fuego [3]. Ash (diameter 0.5 cm), lapilli (2 cm), and bomb (6-7 cm) samples from this eruptive day were prepared for melt inclusion analysis to isolate cooling rate as the variable. The ash was prepared without any modification, and represents 20 seconds of cooling. The outer 1 mm of the lapilli was removed to isolate material exposed to 1-2 minutes of cooling. The bombs were sectioned into 2x2x2 cm cores to reflect cooling on the order of 5-10 minutes [4]. Ion and electron probe analyses of the melt inclusions and olivines yield similar major element (52-54% SiO2) and olivine compositions (Fo#72-77) that match previously published results. Melt inclusions from the ash and lapilli samples record the highest H2O contents, up to 4.5 wt%, which are likely recording pre-eruptive conditions rapidly quenched during eruption. On the other hand, those in the bomb samples indicate 15-35% H2O loss (up to 1 wt% H2O), for inclusions with similar S and K2O concentrations, due to the longer time available for re-equilibration with the degassing magma through olivine. Inclusions from the larger clasts also record 5-10% post-entrapment crystallization of olivine , while those from the ash samples record none. Thus, cooling times on the order of 5-10 minutes are long enough to affect H2O concentrations and Fe/Mg ratios within olivine-hosted melt inclusions. This result reveals potential problems with prior published work on melt inclusions from bomb or lava flow samples. Future sampling of basaltic volcanic deposits should be restricted to pyroclasts less than 2 cm in diameter in order to minimize post-eruptive H2O loss during degassing and diffusion. [1] Portnyagin, et al., EPSL, 2008. [2] Demouchy, et al., Geology, 2006. [3] Rose, et al., JVGR, 1978. [4] Thomas and Sparks, Bull. Volcanol, 1992.

Lloyd, A. S.; Plank, T.; Ruprecht, P.; Hauri, E. H.; Rose, W. I.

2010-12-01

246

The unemployment rate, unemployment volatility, and crime  

Microsoft Academic Search

Purpose – The paper aims to study the effect of the unemployment rate and its volatility on crime in the USA. It proposes that not only the unemployment rate, but also its volatility affect the crime. Design\\/methodology\\/approach – First, the volatility of the unemployment rate is calculated using ARCH models. Next, using the results from the first stage the ARDL

Firouz Fallahi; Hamed Pourtaghi; Gabriel Rodríguez

2012-01-01

247

Plant Volatiles: Recent Advances and Future Perspectives  

Microsoft Academic Search

Volatile compounds act as a language that plants use for their communication and interaction with the surrounding environment. To date, a total of 1700 volatile compounds have been isolated from more than 90 plant families. These volatiles, released from leaves, flowers, and fruits into the atmosphere and from roots into the soil, defend plants against herbivores and pathogens or provide

Natalia Dudareva; Florence Negre; Dinesh A. Nagegowda; Irina Orlova

2006-01-01

248

Forecasting Volatility in Financial Markets: A Review  

Microsoft Academic Search

Financial market volatility is an important input for investment, option pricing, and financial market regulation. The emphasis of this review article is on forecasting instead of modelling; it compares the volatility forecasting findings in 93 papers published and written in the last two decades. Provided in this paper as well are volatility definitions, insights into problematic issues of forecast evaluation,

Ser-Huang Poon; Clive W. J. Granger

2003-01-01

249

Inhibition of prostate cancer (LNCaP) cell proliferation by volatile components from Nagami kumquats.  

PubMed

Fresh Nagami kumquats (Fortunella margarita) were subjected to hydrodistillation using a Clevenger-type apparatus to obtain volatile oil. The chemical composition of the volatile oil was analyzed by GC-MS using Rtx-5 Sil MS and DB Wax columns. A total of 25 volatile compounds were identified by mass spectra, retention index, and comparison with known standards. The major identified compounds are d-limonene (41.64 %), ?-myrecene (16.54 %), linalyl propionate (9.55 %), and germacrene-D (5.93 %) from the Rtx-5 Sil MS column; d-limonene and ?-myrecene were also separated as major compounds on the DB wax column. The oil is rich in hydrocarbons (77.41 %) consisting of 60.05 % monoterpenes and 17.36 % sesquiterpenes. Interestingly, oxygenated hydrocarbons (17.6 %) were also found in kumquat volatile oil. Certain volatile compounds were also confirmed by positive chemical ionization and NMR spectra. Further, the volatile oil demonstrated good DPPH radical scavenging activity and antioxidant capacity. Kumquat volatile oil at 200 ppm concentration exhibited 55 %, 61 %, and 63.4 % inhibition of human prostate cancer (LNCaP) cell proliferation at 24, 48, and 72 h, respectively, by cell count assays. Significant increases in expression of bax/bcl2 and p53 proteins confirmed that volatile oil induces apoptosis. In addition, inhibition of inflammatory markers such as NF-?B and Cox-2 was observed. The cleavage of caspase-8 in the LNCaP cells treated with volatile oil demonstrated that apoptosis occurred through an extrinsic pathway. This is the first report of the identification and possible mechanisms of in vitro antiproliferative effects of kumquat volatile components on human prostate cancer (LNCaP) cells. PMID:22673830

Jayaprakasha, Guddadarangavvanahally K; Murthy, Kotamballi N Chidambara; Demarais, Rock; Patil, Bhimanagouda S

2012-06-06

250

Effect of fermentation conditions on yeast growth and volatile composition of wine produced from mango ( Mangifera indica L.) fruit juice  

Microsoft Academic Search

In this study mango juice fermentation at laboratory scale with controlled inoculation using selected yeast strain was performed (Saccharomyces cerevisiae 101). Effect of fermentation conditions (temperature, pH, SO2 and aeration) on wine fermentation was evaluated based on yeast growth, duration, fermentation rate and volatile composition. The composition of the major volatile compounds with low boiling points was determined by gas

L. V. A. Reddy; O. V. S. Reddy

2011-01-01

251

Contribution of non methane organic volatiles exchange to the carbon budget of isoprene and monoterpene emitting plant species  

Microsoft Academic Search

Compared to the aerosol fraction, most of the organic carbon present in the atmosphere is found in form of volatile or semivolatile compounds. Vegetation was identified being the major source of these organic volatiles, releasing carbon at the same order of magnitude as the global net biome productivity (NBP). To achieve an estimate of plants carbon exchange, including the emission

T. Dindorf; U. Kuhn; C. Ammann; A. Neftel; C. Tritsch; P. Ciccioli; R. Koppmann; J. Kesselmeier

2003-01-01

252

Volatile substance misuse : clinical considerations, neuropsychopharmacology and potential role of pharmacotherapy in management.  

PubMed

Volatile substance misuse is among the most prevalent and toxic forms of psychoactive drug use, and often results in highly deleterious social, psychological and medical consequences. The prevalence of this pernicious form of substance misuse owes in part to the fact that volatile substances of misuse are ubiquitous in the natural environment. Commonly misused commercial products include glue, shoe polish, nail polish remover, butane lighter fluid, gasoline and computer duster spray. National samples of volatile substance misusers tend to exhibit high rates of psychiatric problems and antisocial behaviour. In addition, cognitive impairments and affective dysregulation are often observed among these individuals. Volatile substances exert their complex neuropharmacological effects on dopaminergic, glutamatergic, GABAergic and serotoninergic receptor systems, as well as on cell membranes and ion channels. Concomitantly, pharmacotherapies for volatile substance abuse might profitably target a number of mechanisms, including reward circuitry in the brain, symptoms of craving and withdrawal, neuropsychiatric and emotional impairments that promote volatile substance abuse, and cognitive enhancement to rectify deficits in executive function. This review details the modes of use, subjective effects, epidemiology, adverse consequences, neuropsychopharmacology and drug treatment of volatile substance misuse, and discusses the potential role of novel forms of pharmacological intervention for this oft-overlooked public health threat of epidemic proportions. PMID:23018545

Garland, Eric L; Howard, Matthew O

2012-11-01

253

Chirospecific analysis of plant volatiles  

NASA Astrophysics Data System (ADS)

Characteristic features of the analysis of plant volatiles by enantioselective gas (gas-liquid) chromatography and gas chromatography/mass spectrometry are discussed. The most recent advances in the design of enantioselective stationary phases are surveyed. Examples of the preparation of the most efficient phases based on modified cyclodextrins are given. Current knowledge on the successful analytical resolution of different types of plant volatiles (aliphatic and aromatic compounds and mono-, sesqui- and diterpene derivatives) into optical antipodes is systematically described. Chiral stationary phases used for these purposes, temperature conditions and enantiomer separation factors are summarised. Examples of the enantiomeric resolution of fragrance compounds and components of plant extracts, wines and essential oils are given.

Tkachev, A. V.

2007-10-01

254

The volatile composition of comets  

SciTech Connect

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.

Weaver, H.A.

1988-11-01

255

Volatile constituents of Trichothecium roseum.  

PubMed

In the course of investigation of Trichothecium roseum (Fungi Imperfecti) for its attractancy against Tyrophagus putrescentiae (cheese mite), the twenty following volatile compounds produced at a very low concentration by the microfungus were identified by gc, gc/ms, gc/c.i.ms and tlc: 3-methyl-1-butanol, 3-octanone, 1-octen-3-one, 3-octanol, octa-1,5-dien-3 one, 1-octen-3-ol, 6-methyl-5-hepten-2-ol, octa-1,5-dien-3 ol, furfural, linalool, linalyl acetate, terpineol (alpha and beta) citronellyl acetate, nerol, citronellol, phenylacetaldehyde, benzyl alcohol geranyl acetate, 1-phenyl ethanol and nerolidol. Octa-1,5-dien-3-ol and octa-1,5-dien-3-one have not been previously isolated from fungi; octa-1,5-dien-3-ol is the most potent attractant amount the volatile compounds detected by gc. PMID:567852

Vanhaelen, M; Vanhaelen-Fastre, R; Geeraerts, J

1978-06-01

256

Escape of volatiles from Venus  

NASA Astrophysics Data System (ADS)

A model for describing the loss of atmosphere in Venus in the geologic time is presented. The amount of volatiles degassed from Venus in 4.6 Ga is in the order of 286.9 Terrestrial Atmospheric Masses (TAM) (1 TAM = 5.28x1018 kg). If the drag of the solar wind acted since the birth of Venus, 4.6 Ga ago, a minimum limit of the amount of atmosphere lost by the planet is 6.76 TAM. The current atmosphere of Venus has 88.44 TAM of mass. The sum of the lost and the current atmosphere is 95.2 TAM. This result is 191.7 TAM smaller than the estimation of the mass degassed in all the history of Venus. Then we have a deficit of 191.7 TAM of volatiles on Venus. It is well known that the surface of Venus is geologically young (? 500 Ma) In all this period the model predicts that Venus lost, by the solar wind, only 0.08 TAM of atmosphere. From this we can assume that the deficit of volatiles is due to events that occur before that time or perhaps at that time. It is possible to speculate that the resurfacing of Venus, the massive loss of volatiles, and a change from prograde to retrograde rotation of the planet occur at the same time and could be produced by a gigantic impact with a planetary-size body. In this catastrophic event the angular momentum of the planet could change from the original (possibly prograde) to the current one, all the surface of Venus could be melt producing a resurfacing and the water and part of the CO2 in the atmosphere could be ejected to space.

Durand-Manterola, H. J.

257

An Empirical Study of Volatility Predictions: Stock Market Analysis Using Neural Networks  

Microsoft Academic Search

\\u000a Volatility is one of the major factor that causes uncertainty in short term stock market movement. Empirical studies based\\u000a on stock market data analysis were conducted to forecast the volatility for the implementation and evaluation of statistical\\u000a models with neural network analysis. The model for prediction of Stock Exchange short term analysis uses neural networks for\\u000a digital signal processing of

Bernard Fong; Alvis Cheuk M. Fong; G. Y. Hong; Louisa Wong

2005-01-01

258

???????????????????????????????????????????????????????????????????????????????????? Composition and antituberculosis activity of the volatile oil of Heliotropium indicum Linn  

Microsoft Academic Search

The volatile oil from the aerial parts of H. indicum was isolated by hydrodistillation and analyzed by a combination of gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The essential oil was obtained in 0.004% yield as a light brown liquid. The major constituents of the volatile oil of H. indicum were phytol (49.1%), 1-dodecanol (6.4%) and ?-linalool (3.0%). In

Theeraphan Machan; John Korth; Boonsom Liawruangrath; Saisunee Liawruangrath; Stephen G. Pyne

259

Chemical characterization and allelopathic potential of volatile oil of Eucalyptus tereticornis against Amaranthus viridis  

Microsoft Academic Search

The present study investigated the chemical composition and allelopathic potential of volatile oil from Eucalyptus tereticornis on growth and establishment of Amaranthus viridis, a wasteland weed. The volatile oil was rich in monoterpenoids and a total of 34 components were identified by gas chromatography\\/gas chromatography–mass spectroscopy analyses, constituting 98.52%. ?-Pinene (32.5%) and 1,8-cineole (22.4%) were the two major constituents. The

Shalinder Kaur; Harminder Pal Singh; Daizy Rani Batish; Ravinder Kumar Kohli

2011-01-01

260

Biological roles of monoterpene volatiles derived from rough lemon ( Citrus jambhiri Lush) in citrus defense  

Microsoft Academic Search

Volatile compounds of plants, including monoterpenes, are a possible source of signal molecules that induce defense systems\\u000a to protect plants from tissue damage. Volatile compounds from rough lemon leaves were trapped by solid-phase microextraction\\u000a fibers in sealed vials, and subsequent gas chromatography–mass spectrometry and gas chromatography analyses identified the\\u000a profile of the major components, mainly various monoterpenes. Among several monoterpenes

Yumiko Yamasaki; Hitoshi Kunoh; Hiroyuki Yamamoto; Kazuya Akimitsu

2007-01-01

261

Exchange-rate volatility in Latin America and its impact on foreign trade  

Microsoft Academic Search

This paper investigates empirically the impact of real exchange-rate volatility on the export flows of eight Latin American countries over the quarterly period 1973–1997. Estimates of the cointegrating relations are obtained using Johansen's multivariate procedure. Estimates of the short-run dynamics are obtained utilizing the error-correction technique. The major results show that increases in the volatility of the real effective exchange

Augustine C. Arize; Thomas Osang; Daniel J. Slottje

262

Exchange-rate volatility in Latin America and its impact on foreign trade  

Microsoft Academic Search

This paper investigates empirically the impact of real exchange-rate volatility on the export flows of eight Latin American countries over the quarterly period 1973–2004. Estimates of the cointegrating relations are obtained using different cointegration techniques. Estimates of the short-run dynamics are obtained for each country utilizing the error-correction technique. The major results show that increases in the volatility of the

Augustine C. Arize; Thomas Osang; Daniel J. Slottje

2008-01-01

263

Characterization of volatile aroma compounds in cooked black rice.  

PubMed

Black rice ( Oryza sativa L.), an aromatic specialty rice popular in Asia, has a unique flavor, the volatile chemistry of which has not been reported. The objectives of this research were to study volatile profiles of cooked black rice and to characterize the odor-active compounds. Thirty-five volatile compounds were identified by gas chromatography-mass spectrometry using a dynamic headspace system with Tenax trapping. Aldehydes and aromatics were quantitatively in the greatest abundance, accounting for 80.1% of total relative concentration of volatiles. The concentration of 2-acetyl-1-pyrroline (2-AP) was high, exceeded only by hexanal, nonanal, and 2-pentylfuran. A total of 25 odor-active compounds, determined by gas chromatography-olfactometry, were applied to principal component analysis, demonstrating significant differences between a black and a traditional white rice cultivar in terms of aroma and explaining 93.0% of the total variation. 2-AP, guaiacol, indole, and p-xylene largely influenced the difference between the aroma in cooked black and white rice. 2-AP and guaiacol were major contributors to the unique character of black rice based on odor thresholds, relative concentrations, and olfactometry. PMID:18081248

Yang, Dong Sik; Lee, Kyu-Seong; Jeong, O-Young; Kim, Kee-Jong; Kays, Stanley J

2007-12-15

264

Forecasting volatility of fuel oil futures in China: GARCH-type, SV or realized volatility models?  

NASA Astrophysics Data System (ADS)

In most previous works on forecasting oil market volatility, squared daily returns were taken as the proxy of unobserved actual volatility. However, as demonstrated by Andersen and Bollerslev (1998) [22], this proxy with too high measurement noise could be perfectly outperformed by a so-called realized volatility (RV) measure calculated by the cumulative sum of squared intraday returns. With this motivation, we further extend earlier works by employing intraday high-frequency data to compare the performance of three typical volatility models in the daily out-of-sample volatility forecasting of fuel oil futures on the Shanghai Futures Exchange (SHFE): the GARCH-type, stochastic volatility (SV) and realized volatility models. By taking RV as the proxy of actual daily volatility and then computing forecasting errors, we find that the realized volatility model based on intraday high-frequency data produces significantly more accurate volatility forecasts than the GARCH-type and SV models based on daily returns. Furthermore, the SV model outperforms many linear and nonlinear GARCH-type models that capture long-memory volatility and/or the asymmetric leverage effect in volatility. These results also prove that abundant volatility information is available in intraday high-frequency data, and can be used to construct more accurate oil volatility forecasting models.

Wei, Yu

2012-11-01

265

Mapping fault-controlled volatile migration in equatorial layered deposits on Mars  

NASA Astrophysics Data System (ADS)

Research in terrestrial settings shows that clastic sedimentary deposits are productive host rocks for underground volatile reservoirs because of their high porosity and permeability. Within such reservoirs, faults play an important role in controlling pathways for volatile migration, because faults act as either barriers or conduits. Therefore faults are important volatile concentrators, which means that evidence of geochemical, hydrologic and biologic processes are commonly concentrated at these locations. Accordingly, faulted sedimentary deposits on Mars are plausible areas to search for evidence of past volatile activity and associated processes. Indeed, evidence for volatile migration through layered sedimentary deposits on Mars has been documented in detail by the Opportunity rover in Meridiani Planum. Thus evidence for past volatile- driven processes that could have occurred within the protective depths of these deposits may now exposed at the surface and more likely found around faults. Owing to the extensive distribution of layered deposits on Mars, a major challenge in looking for and investigating evidence of past volatile processes in these deposits is identifying and prioritizing study areas. Toward this end, this presentation details initial results of a multiyear project to develop quantitative maps of latent pathways for fault-controlled volatile migration through the layered sedimentary deposits on Mars. Available MOC and THEMIS imagery are used to map fault traces within equatorial layered deposits, with an emphasis on proposed regions for MSL landing sites. These fault maps define regions of interest for stereo imaging by HiRISE and identify areas to search for existing MOC stereo coverage. Stereo coverage of identified areas of interest allows for the construction of digital elevation models and ultimately extraction of fault plane and displacement vector orientations. These fault and displacement data will be fed through numerical modeling techniques that are developed for exploring terrestrial geologic reservoirs. This will yield maps of latent pathways for volatile migration through the faulted layered deposits and provide insight into the geologic history of volatiles on Mars.

Okubo, C. H.

2006-12-01

266

Stochastic volatility models and Kelvin waves  

NASA Astrophysics Data System (ADS)

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics.

Lipton, Alex; Sepp, Artur

2008-08-01

267

AMBIENT LEVEL VOLATILE ORGANIC COMPOUND (VOC) MONITORING USING SOLID ADSORBANTS - RECENT U.S. EPA STUDIES  

EPA Science Inventory

Ambient air spiked with 1-10 ppbv concentrations of 41 toxic volatile organic compounds (VOCs) listed in U.S. Environmental Protection Agency (EPA) Compendium Method TO-14A was monitored using solid sorbents for sample collection and a Varian Saturn 2000 ion trap mass spectrome...

268

Volatile accretion history of the Earth.  

PubMed

It has long been thought that the Earth had a protracted and complex history of volatile accretion and loss. Albarède paints a different picture, proposing that the Earth first formed as a dry planet which, like the Moon, was devoid of volatile constituents. He suggests that the Earth's complement of volatile elements was only established later, by the addition of a small veneer of volatile-rich material at ?100 Myr (here and elsewhere, ages are relative to the origin of the Solar System). Here we argue that the Earth's mass balance of moderately volatile elements is inconsistent with Albarède's hypothesis but is well explained by the standard model of accretion from partially volatile-depleted material, accompanied by core formation. PMID:20981045

Wood, B J; Halliday, A N; Rehkämper, M

2010-10-28

269

Relation of Specific Conductance in Ground Water to Intersection of Flow Paths by Wells, and Associated Major Ion and Nitrate Geochemistry, Barton Springs Segment of the Edwards Aquifer, Austin, Texas, 1978-2003  

USGS Publications Warehouse

Understanding of karst flow systems can be complicated by the presence of solution-enlarged conduits, which can transmit large volumes of water through the aquifer rapidly. If the geochemistry at a well can be related to streamflow or spring discharge (springflow), or both, the relations can indicate the presence of recent recharge in water at the well, which in turn might indicate that the well intersects a conduit (and thus a major flow path). Increasing knowledge of the occurrence and distribution of conduits in the aquifer can contribute to better understanding of aquifer framework and function. To that end, 26 wells in the Barton Springs segment of the Edwards aquifer, Austin, Texas, were investigated for potential intersection with conduits; 26 years of arbitrarily timed specific conductance measurements in the wells were compared to streamflow in five creeks that provide recharge to the aquifer and were compared to aquifer flow conditions as indicated by Barton Springs discharge. A nonparametric statistical test (Spearman's rho) was used to divide the 26 wells into four groups on the basis of correlation of specific conductance of well water to streamflow or spring discharge, or both. Potential relations between conduit intersection by wells and ground-water geochemistry were investigated through analysis of historical major ion and nitrate geochemistry for wells in each of the four groups. Specific conductance at nine wells was negatively correlated with both streamflow and spring discharge, or streamflow only. These correlations were interpreted as evidence of an influx of surface-water recharge during periods of high streamflow and the influence at the wells of water from a large, upgradient part of the aquifer; and further interpreted as indicating that four wells intersect major aquifer flow paths and five wells intersect minor aquifer flow paths (short, tributary conduits). Specific conductance at six wells was positively correlated with spring discharge, which was interpreted as not intersecting a flow path (conduit). Of the 11 wells for which specific conductance did not correlate with either streamflow or spring discharge, no interpretations regarding flow-path intersection by wells were made. In some cases, specific conductance data might not have indicated intersection with a flow path because of small sample sets. Water in the Barton Springs segment generally is a calcium-magnesium-bicarbonate type, although some water compositions deviate from this. Multiple geochemical processes were identified that might affect geochemistry at the wells, but in general the geochemical composition of ground water, except for dilution by surface-water recharge, was not related to intersection of a well with a flow path. Some samples from wells indicate inflow of water from the saline zone to the east; this inflow is associated with low streamflow and spring discharge. Other samples indicate that the aquifer at some wells might be receiving water that has been in contact with rocks of the Trinity aquifer; this mixing is most evident when spring discharge is high. Occurrence of nitrate in ground water was unrelated to intersection of flow paths by wells and appeared to be the result of localized contamination. However, most of the wells with one or more samples contaminated by nitrate are in the more densely populated parts of the study area.

Garner, Bradley D.; Mahler, Barbara J.

2007-01-01

270

Volatile Components of Lawsonia inermis L. Flowers  

Microsoft Academic Search

The volatile constituents of yellow and red Lawsonia inermis L. (henna) flowers were analyzed by capillary GC and GC\\/MS following isolation by solvent extraction. The total yield of volatiles isolated was higher from the yellow flowers which also differed markedly from the red flowers in volatile composition, the former giving greater proportions of ?-ionone (48.6% vs 2.5%) and its derivatives,

K. C. Wong; Y. E. Teng

1995-01-01

271

Multivariate Modeling of Daily REIT Volatility  

Microsoft Academic Search

This paper examines volatility in REITs using a multivariate GARCH based model. The Multivariate VAR–GARCH technique documents\\u000a the return and volatility linkages between REIT sub-sectors and also examines the influence of other US equity series. The\\u000a motivation is for investors to incorporate time-varyng volatility and correlations in their portfolio selection. The results\\u000a illustrate the differences in results when higher frequency

John Cotter; Simon Stevenson

2006-01-01

272

Next-generation non-volatile memory  

Microsoft Academic Search

Recently, Next-generation non-volatile memories continue to receive great attention due to its scalability, rapid read and write performance, simple structure, and easy incorporation with CMOS process. There are many candidates for ideal non-volatile memory, such as Magnetro-resistive RAM (MRAM), Phase change RAM (PCRAM), and Resistive RAM (RRAM). This talk will discuss the strengths and weaknesses of different emerging non-volatile memory

Ming-Jer Kao

2007-01-01

273

Predicting stock market volatility: A new measure  

Microsoft Academic Search

INTRODUCTIONThe CBOE Market Volatility Index (VIX) is an average of S&P 100option (OEX) implied volatilities. As such, it represents a market-consensus estimate of future stock market volatility. 1 The computationand dissemination of VIX on a real-time basis offers practitioners andacademics an important new source of information. Practitioners, forThis research was supported by the Futures and Options Research Center at the

Jeff Fleming; Barbara Ostdiek; Robert E. Whaley

1995-01-01

274

Study of the volatile compounds produced by Debaryomyces hansenii NRRL Y-7426 during the fermentation of detoxified concentrated distilled grape marc hemicellulosic hydrolysates.  

PubMed

The volatile compounds produced by Debaryomyces hansenii NRRL Y-7426 during the fermentation of detoxified concentrated distilled grape marc hemicellulosic hydrolysates was analysed by GC-MS. Thirty-five compounds corresponding to ten groups of volatile compounds: terpenes, higher alcohols, C? alcohols, aldehydes, volatile acids, acetates, ethyl esters, volatile phenols, sulphur compounds and hydrocarbons were identified. The supplementation with commercial nutrients increased the concentration of 2-phenylethanol, a commercial flavour and fragrance compound, with a rose-like odour, employed in cosmetics and food industries; and other positive compounds to the aroma such as terpenes and ethyl esters. Non-supplemented media produced the highest content in higher alcohols, volatile acids, sulphur compounds and in the majority of hydrocarbons detected, meanwhile supplementation with vinasses hardly produced volatile compounds. Only four volatile compounds contributed directly to the aroma according to the OAVs values higher than 1. Finally, a PCA analysis allowed accounting for 100 % of the variance. PMID:22806750

Salgado, José Manuel; González-Barreiro, Carmen; Rodríguez-Solana, Raquel; Simal-Gándara, Jesús; Domínguez, José Manuel; Cortés, Sandra

2012-07-12

275

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

PubMed

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

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

2008-12-16

276

Volatilization of the pesticides chlorpyrifos and fenpropimorph from a potato crop.  

PubMed

Volatilization of pesticides from crops in the field can be an important emission pathway. In a field experiment with characterization of meteorological conditions, the pesticides chlorpyrifos and fenpropimorph were sprayed onto a potato crop, after which concentrations in the air and on/in the plants were measured. Rates of volatilization were estimated with the aerodynamic profile (ADP), energy balance (EB), relaxed eddy accumulation (REA), and plume dispersion (PD) methods. The volatilization rates obtained with the ADP and EB methods were similar, while some rates obtained with the REA and PD methods in the initial period were lower. Cumulative volatilization of chlorpyrifos during daylight hours (ADP and EB methods) was estimated to be about 65% of the dosage. By far the majority of this volatilization occurred in the first few days. Competing processes at the plant surface had a considerable effect on the dissipation of fenpropimorph, so cumulative volatilization during daylight hours was estimated to be only 7% of the dosage. Plant surface residues were higher than would correspond with the volatilization rate, indicating that penetration into the leaves had occurred. PMID:16433338

Leistra, Minze; Smelt, Johan H; Weststrate, J Hilbrand; van den Berg, Frederik; Aalderink, René

2006-01-01

277

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

PubMed Central

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.

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

2009-01-01

278

Effect of the type of oil on the evolution of volatile compounds of taralli during storage.  

PubMed

Baking process leads to a huge quantity of newly formed volatile compounds, which play a major role in developing the flavor of the final product. The aim of this work was to investigate on the evolution of the volatile profile of taralli as a function of both the kind of oil used in the dough and the storage time. The volatile compounds from the taralli were extracted by headspace solid-phase microextraction and analyzed by gas-chromatography/mass spectrometry (GC/MS). Forty-four volatile compounds were identified in taralli, most of which produced by thermically induced reactions occurring during baking process, such as volatiles deriving from Maillard reaction and/or sugar degradation and lipid oxidation. The results obtained demonstrated the essential role played by the type of oil on the formation and on the release of volatile compounds. The volatile compounds significantly increased during storage and their individual levels were in most cases significantly lower in taralli made with extra virgin olive oil than in those made with refined oils. Finally, the taralli made with extra virgin olive oil, compared with those prepared with other vegetable oils, showed to be more resistant to oxidation, probably due to the presence of natural antioxidants. PMID:22384958

Giarnetti, Mariagrazia; Caponio, Francesco; Paradiso, Vito M; Summo, Carmine; Gomes, Tommaso

2012-03-01

279

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

PubMed

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

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

2012-07-24

280

Volatile Release From The Siberian Traps Inferred From Melt Inclusions  

NASA Astrophysics Data System (ADS)

The Siberian Traps Large Igneous Province is one of the largest known continental flood volcanic provinces in the Phanerozoic. The quantification of volatile degassing is particularly important because the Siberian Traps have often been invoked as a possible trigger for the end-Permian mass extinction (e.g. Campbell et al., 1992; Wignall, 2001). Volatile degassing provides a crucial mechanism to link mafic volcanic eruption with global environmental change. Mafic flood basalt magmas are expected to have low volatile contents (similar to mid-ocean ridge basalts). However, Siberian Traps magmas were chambered in and erupted through a thick sedimentary basin and may have interacted with, and obtained volatiles from, sedimentary lithologies such as limestone, coal, and evaporite. Melt inclusions from the Siberian Traps provide insight into the potential total volatile budget throughout the evolution of the large igneous province. These droplets of trapped melt may preserve volatile species that would otherwise have degassed at the time of eruption. We present data from the analysis of more than 100 melt inclusions, including both homogenized inclusions and rare glassy inclusions with low crystallinity. Many melt inclusions from tuffs and flows near the base of the Siberian Traps sequence are substantially enriched in chlorine and fluorine compared to Deccan Traps and Laki melt inclusions (Self et al., 2008; Thordarson et al., 1996). These inclusions record chlorine concentrations up to ~1400 ppm, and fluorine concentrations up to ~5000 ppm. Olivines from the Maymechinsky suite, recognized as the last extrusive products of Siberian Traps volcanism, contain melt inclusions with maximum sulfur concentrations in the range of ~5000 ppm and substantial concentrations of chlorine. Intrusive igneous rocks from the province also display significant volatile contents. A sill from the Ust-Ilimsk region yielded plagioclase-hosted melt inclusions which contain chlorine and fluorine concentrations in the range of one weight percent. Visscher et al. (2004) proposed that chlorofluorocarbon compounds (CFCs) may have played a major role in the terrestrial end-Permian extinction. These CFCs are powerful catalysts for the breakdown of ozone, a process which can expose the biosphere to increased ultraviolet radiation. Measurements of elevated chlorine and fluorine from the Siberian Traps may thus provide a concrete source for CFCs that could have triggered this kill mechanism.

Black, Benjamin A.; Elkins-Tanton, Linda T.; Rowe, Michael C.; Ukstins Peate, Ingrid

2010-05-01

281

THEORETICAL EVALUATION OF STABILITY OF VOLATILE ORGANIC CHEMICALS AND POLAR VOLATILE ORGANIC CHEMICALS IN CANISTERS  

EPA Science Inventory

A mathematical model was developed for describing loss by physical adsorption of volatile organic chemicals (VOCs) and polar volatile organic chemicals (PVOCs) in stainless steel canisters. he model incorporates compound specific properties such as polarizability, vapor concentra...

282

Low volatile organic compound paints  

SciTech Connect

Increasingly stringent air emission standards in various states has dictated the elimination of engineering finishes which are derived from high volatile organic compound (VOC) paint chemistries. In July 1989, Allied-Signal, Inc., Kansas City Division, Kansas City, Missouri, voluntarily closed its paint facility, due to non-compliance with local air emission standards. The following details the materials selection and evaluations which led to current processing using low VOC paints, which permitted the Allied Signal, Inc., paint facility to achieve compliance and resume operations. 1 tab.

Martinez, F.E.

1991-01-01

283

[Chemical components of Vetiveria zizanioides volatiles].  

PubMed

The chemical components of the volatiles from Vetiveria zizanioides were analyzed by SPME and GC-MS. In the roots, the main component was valencene (30.36%), while in the shoots and leaves, they were 9-octadecenamide (33.50%), 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene (27.46%), and 1,2-benzendicarboxylic acid, diisooctyl ester(18.29%). The results showed that there were many terpenoids in the volatils. In shoot volatiles, there existed 3 monoterpenes, 2 sequiterpenes and 1 triterpene. Most of the volatiles in roots were sesquiterpenes. PMID:15139214

Huang, Jinghua; Li, Huashou; Yang, Jun; Chen, Yufen; Liu, Yinghu; Li, Ning; Nie, Chengrong

2004-01-01

284

Ion beam exposure characteristics of nitrocellulose  

Microsoft Academic Search

Nitrocellulose resist layers were irradiated by 50 keV Li+, Si+, Ga+ and In +ions. It was found that nitrocellulose functions as a self-developing (i.e. volatile) resist when it is exposed to heavy ions (Ga+, In+). For the case of light ions (Li +, Si+) a small amount of a nonvolatile residue is formed. For low enough doses the developed resist

R. Mühle; G. Götz

1990-01-01

285

Influence of recooking on volatile and non-volatile compounds found in silver carp Hypophthalmichthys molitrix  

Microsoft Academic Search

Volatile and non-volatile compounds, which contribute to flavor in raw fish, were compared in raw, cooked and recooked silver\\u000a carp. In total, 20, 34 and 34 volatile compounds, including aldehydes, alcohols, ketones, hydrocarbons and heterocyclic compounds,\\u000a were identified in raw, cooked and recooked samples, respectively. Cooking the samples resulted in a significant increase\\u000a in volatile compounds and the formation of

Jing-Ke Liu; Si-Ming Zhao; Shan-Bai Xiong; Sheng-Hua Zhang

2009-01-01

286

Asymmetric volatility, volatility clustering, and herding agents with a borrowing constraint  

NASA Astrophysics Data System (ADS)

Recent empirical research has documented asymmetric volatility and volatility clustering in stock markets. We conjecture that a limit of arbitrage due to a borrowing constraint and herding behavior by investors are related to these phenomena. This study conducts simulation analyses on a spin model where borrowing constrained agents imitate their nearest neighbors but switch their strategies to a different one intermittently. We show that herding matters for volatility clustering while a borrowing constraint intensifies the asymmetry of volatility through the herding effect.

Yamamoto, Ryuichi

2010-03-01

287

Can Internet search queries help to predict stock market volatility?  

Microsoft Academic Search

This paper studies the dynamics of stock market volatility and retail investor attention measured by internet search queries. We find a strong co-movement of stock market indices' realized volatility and the search queries for their names. Furthermore, Granger causality is bi-directional: high searches follow high volatility, and high volatility follows high searches. Using the latter feedback effect to predict volatility

Thomas Dimpfl; Stephan Jank

2011-01-01

288

Can internet search queries help to predict stock market volatility?  

Microsoft Academic Search

This paper studies the dynamics of stock market volatility and retail investor attention measured by internet search queries. We find a strong co-movement of stock market indices' realized volatility and the search queries for their names. Furthermore, Granger causality is bi-directional: high searches follow high volatility, and high volatility follows high searches. Using the latter feedback effect to predict volatility

Thomas Dimpfl; Stephan Jank

2011-01-01

289

Econometric analysis of realized volatility and its use in estimating stochastic volatility models  

Microsoft Academic Search

The availability of intraday data on the prices of speculative assets means that we can use quadratic variation-like measures of activity in financial markets, called realized volatility, to study the stochastic properties of returns. Here, under the assumption of a rather general stochastic volatility model, we derive the moments and the asymptotic distribution of the realized volatility error-the difference between

Ole E. Barndorff-Nielsen; Neil Shephard

2002-01-01

290

Citrus Leaf Volatiles as Affected by Developmental Stage and Genetic Type  

PubMed Central

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.

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

2013-01-01

291

Carbon Concentration Excursions in Apatite Phenocrysts from the Cerro Galan Ignimbrite: A SIMS View into the Transient pre-Eruptive Volatile History of a Supervolcano  

NASA Astrophysics Data System (ADS)

In nearly all igneous rock compositions, apatite is the most abundant mineral that regularly incorporates significant quantities of volatile elements into its structure, making it a potentially useful tool for exploring magmatic processing of volatiles (as well as REEs, Sr, Nd, and Pb isotopes, all of which are typically abundant in apatite). We have developed an analytical protocol that permits measurement of C, H, F, S, and Cl in ~8?m diameter regions of apatite using the Cameca 6f SIMS. A primary Cs+ beam (4-10 nA) is used in conjunction with electron gun charge-compensation to sputter negative ions from polished sections and unpolished crystal faces mounted in volatile-free indium mounts. We operated at mass resolving powers sufficient to separate all potential interferences (such as ^{31}PH and 16O2 from ^{32}S, and 17O from 16OH). Quantifying the SIMS data requires a set of standards that are 1) homogeneous at the few-micron scale; and 2) well-calibrated with multiple, reliable, independent volatile content measurements. Using values combed from the literature and other unpublished sources, we have assembled a set of apatite standards, none of which are proven to meet either criteria. Nevertheless, these materials allow us to create calibration curves for all of the volatile elements listed above. Traverses across polished basal sections of apatite phenocrysts from the ~1000 km3 Cerro Galan ignimbrite, Argentina (courtesy of C. Schirnick) yield the following results: Apatites are fluorine-rich, and contain significant and reproducible intracrystalline variations in C, H, S, and Cl. Positive carbon concentration excursions (up to 360 ppm) are factors of 2-7 greater than apatite baseline concentrations (40-60 ppm), the largest of which correlate with position in different grains. In the majority of the traverses, these carbon excursions also correlate spatially with 25-30% increases in sulfur concentration. We suggest that these dramatic increases in carbon and sulfur concentrations record a transient increase in magmatic SO4^{2- } and CO2 activities, perhaps the result of an underplating/recharge event, followed by a return to baseline magma chemistry. Hydrogen-poor rims are observed in all studied crystals, and are accompanied by chlorine-impoverished rims in a majority of the traverses, perhaps recording the pre- or syn-eruption exsolution of a vapor phase enriched in H and Cl.

Boyce, J. W.; Hervig, R. L.

2006-12-01

292

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

PubMed

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

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

2013-09-17

293

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

PubMed Central

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.

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

2012-01-01

294

Volatile exchange between undamaged plants - a new mechanism affecting insect orientation in intercropping.  

PubMed

Changes in plant volatile emission can be induced by exposure to volatiles from neighbouring insect-attacked plants. However, plants are also exposed to volatiles from unattacked neighbours, and the consequences of this have not been explored. We investigated whether volatile exchange between undamaged plants affects volatile emission and plant-insect interaction. Consistently greater quantities of two terpenoids were found in the headspace of potato previously exposed to volatiles from undamaged onion plants identified by mass spectrometry. Using live plants and synthetic blends mimicking exposed and unexposed potato, we tested the olfactory response of winged aphids, Myzus persicae. The altered potato volatile profile deterred aphids in laboratory experiments. Further, we show that growing potato together with onion in the field reduces the abundance of winged, host-seeking aphids. Our study broadens the ecological significance of the phenomenon; volatiles carry not only information on whether or not neighbouring plants are under attack, but also information on the emitter plants themselves. In this way responding plants could obtain information on whether the neighbouring plant is a competitive threat and can accordingly adjust their growth towards it. We interpret this as a response in the process of adaptation towards neighbouring plants. Furthermore, these physiological changes in the responding plants have significant ecological impact, as behaviour of aphids was affected. Since herbivore host plants are potentially under constant exposure to these volatiles, our study has major implications for the understanding of how mechanisms within plant communities affect insects. This knowledge could be used to improve plant protection and increase scientific understanding of communication between plants and its impact on other organisms. PMID:23922710

Ninkovic, Velemir; Dahlin, Iris; Vucetic, Andja; Petrovic-Obradovic, Olivera; Glinwood, Robert; Webster, Ben

2013-07-29

295

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source  

SciTech Connect

We investigated the ion-loss distribution on the sidewall of an electron cyclotron resonance (ECR) plasma chamber using the 18-GHz ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex (TRIAC). Similarities and differences between the ion-loss distributions (longitudinal and azimuthal) of different ion species (i.e., radioactive {sup 111}In{sup 1+} and {sup 140}Xe{sup 1+} ions that are typical volatile and nonvolatile elements) was qualitatively discussed to understand the element dependence of the charge breeding efficiency. Especially, the similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

Jeong, S. C.; Oyaizu, M.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Miyatake, H.; Niki, K.; Okada, M.; Watanabe, Y. X. [Institute for Particle and Nuclear Physics (IPNS), High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Otokawa, Y.; Osa, A.; Ichikawa, S. [Institute of Atomic Energy Science, Japan Atomic Energy Agency (JAEA), Shiragata Shirakane 2-4, Tokai, Ibaraki 319-1195 (Japan)

2012-02-15

296

Non-parametric estimation of historical volatility  

Microsoft Academic Search

Evolving volatility is a dominant feature observed in most financial time series and a key parameter used in option pricing and many other financial risk analyses. A number of methods for non-parametric scale estimation are reviewed and assessed with regard to the stylized features of financial time series. A new non-parametric procedure for estimating historical volatility is proposed based on

John A Randal; Peter J Thomson; Martin T Lally

2004-01-01

297

Seasonal long-memory stochastic volatility  

NASA Astrophysics Data System (ADS)

In this paper, we propose an alternative approach to estimation of seasonal long-memory stochastic volatility based on the generalized long-memory stochastic volatility (GLMSV) model. We show that the estimator is consistent. We investigate the small sample performance of the estimator by simulation. An application to actual data is also presented.

Gonzaga, Alex C.

2013-10-01

298

Volatility transmission patterns and terrorist attacks  

Microsoft Academic Search

The objective of this study is to analyse volatility transmission between the US and Eurozone stock markets considering the financial market responses to the September 11, March 11 and July 7 terrorist attacks. In order to do this, we use a multivariate GARCH model and take into account the asymmetric volatility phenomenon, the non-synchronous trading problem and the turmoil periods

Helena Chuliá; Francisco Climent; Pilar Soriano; Hipòlit Torró

2009-01-01

299

Simple Volatility Test for Tar Products.  

National Technical Information Service (NTIS)

A simple reliable test to assess the volatility of tar products, especially those of low volatility, has been developed. The mass losses produced by heating small samples of tar products in shallow, open dishes on a thermostatic hot-plate are measured aft...

1978-01-01

300

REAL OPTIONS VOLATILITY ESTIMATION WITH CORRELATED INPUTS  

Microsoft Academic Search

Real Options Analysis (ROA) provides a framework for valuing reactive and proactive managerial flexibility in investment decisions. Estimating the volatility parameter for a real options model is challenging because there are typically no historical returns for the underlying asset and no current market prices. A previously developed method of using simulation to estimate the volatility parameter for a real investment

Barry R. Cobb; John M. Charnes

2004-01-01

301

Some recent developments in stochastic volatility modelling  

Microsoft Academic Search

This paper reviews and puts in context some of our recent work on stochastic volatility (SV) modelling for financial economics. Here our main focus is on: (i) the relationship between subordination and SV, (ii) OU based volatility models, (iii) exact option pricing, (iv) realized power variation and realized variance, (v) building multivariate models.

Ole E Barndorff-Nielsen; Elisa Nicolato; Neil Shephard

2002-01-01

302

Coordinated responsiveness for volatile toy supply chains  

Microsoft Academic Search

Demands for innovative products in short selling windows are highly unpredictable. This volatility creates demands with dramatic peaks and troughs due to risk-avoidance behaviours among manufacturers and retailers. The consequences are high obsolete inventory, lost sales, and markdowns. Theoretically, the concepts of quick response and postponement are among the potential solutions for such as a volatile and seasonal toy supply

C. Y. Wong; H.-H. Hvolby

2007-01-01

303

Predicting Volatility in the Foreign Exchange Market  

Microsoft Academic Search

Measures of volatility implied in option prices are widely believed to be the best available volatility forecasts. In this article, we examine the information content and predictive power of implied standard deviations (ISDs) derived from Chicago Mercantile Exchange options on foreign currency futures. The article finds that statistical time-series models, even when given the advantage of 'ex post' parameter estimates,

Philippe Jorion

1995-01-01

304

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...

305

Lunar Volatiles: An Earth-Moon Perspective.  

National Technical Information Service (NTIS)

It has generally been accepted that the Moon is depleted in volatile elements. However, the recent discovery of measurable water in lunar glasses and apatites suggests that volatiles are not as depleted as was once thought. And, in fact, some authors have...

J. H. Jones

2011-01-01

306

Volatility Persistence in Crude Oil Markets  

Microsoft Academic Search

Financial market participants and policy-makers can benefit from a better understanding of how shocks can affect volatility over time. This study assesses the impact of structural changes and outliers on volatility persistence of three crude oil markets - Brent, West Texas Intermediate (WTI) and Organization of Petroleum Exporting Countries (OPEC) - between January 2, 1985 and June 17, 2010. Firstly,

Amélie Charles; Olivier Darné

2012-01-01

307

Volatility and the natural resource curse  

Microsoft Academic Search

We provide cross-country evidence that rejects the traditional interpretation of the natural resource curse. First, growth depends negatively on volatility of unanticipated output growth independent of initial income, investment, human capital, trade openness, natural resource dependence, and population growth. Second, the direct positive effect of resources on growth is swamped by the indirect negative effect through volatility. Third, with well

Frederick van der Ploeg; Steven Poelhekke

2009-01-01

308

Nuovo tampone volatile da impiegarsi in cromatografia ed elettroforesi  

Microsoft Academic Search

Summary A volatile ethilendiamine-acetate buffer is described which is capable of keeping the pH unaltered during volatilization. The advantages of this buffer in electrophoretic and chromatographic procedures, in comparison with other volatile buffers, are discussed.

P. Fasella; C. Baglioni; C. Turano

1957-01-01

309

Financial volatility: Issues and measuring techniques  

NASA Astrophysics Data System (ADS)

This paper explains in non-technical terms various techniques used to measure volatility ranging from time invariant measures to time variant measures. It is shown that a weakness of the former measures arises from the underlying assumption that volatility is considered to be constant over time. This observation has led researchers to develop time variant measures based on the assumption that volatility changes over time. The introduction of the original ARCH model by Engle has spawned an ever increasing variety of models such as GARCH, EGARCH, NARCH, ARCH-M MARCH and the Taylor Schwert model. The degree of sophistication employed in developing these models is discussed in detail as are the models characteristics used to capture the underlying economic and financial time series data including volatility clustering, leverage effects and the persistence of volatility itself. A feature of these more elaborate models is that they generally obtain a better fit to the data in-sample.

Daly, Kevin

2008-04-01

310

Volatile hydrocarbons in pharmaceutical solutions  

SciTech Connect

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.

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

1991-07-01

311

Analysis of volatile organic compounds of ‘Fuji’ apples following electron beam irradiation and storage  

NASA Astrophysics Data System (ADS)

The volatile organic compounds of non-irradiated and electron-beam irradiated ‘Fuji’ apples (Malus domestica Borkh.) at 0, 0.5, and 1 kGy were isolated through simultaneous distillation extractions and analyzed using gas chromatograph-mass spectrometry. A total of 53 volatile organic compounds were characterized in 0 and 1 kGy irradiated samples, whereas two more compounds related to ketone and terpenoid group were identified in 0.5 kGy irradiated samples. The contents of volatile compounds were 24.33, 36.49, and 35.28 mg/kg in 0, 0.5, and 1 kGy irradiated samples, respectively. The major compounds identified were butanol, hexanal, [E]-2-hexenal, and hexanol in all samples. The relative content of alcohol increased after 30 days of storage in all samples, whereas that of aldehyde decreased. Although the contents of some volatile compounds were changed by electron-beam irradiation, the total yield and major flavor compounds of irradiated ‘Fuji’ apples were similar to, or even greater than, those of the control. Therefore, the application of e-beam irradiation if required for microbial decontamination of ‘Fuji’ apples is an acceptable method as it does not bring about any major quantitative changes of volatile organic compounds.

Song, Hyun-Pa; Shim, Sung-Lye; Lee, Sun-Im; Kim, Dong-Ho; Kwon, Joong-Ho; Kim, Kyong-Su

2012-08-01

312

The ESA Lunar Lander and the search for Lunar Volatiles  

NASA Astrophysics Data System (ADS)

Following the Apollo era the moon was considered a volatile poor body. Samples collected from the Apollo missions contained only ppm levels of water formed by the interaction of the solar wind with the lunar regolith [1]. However more recent orbiter observations have indicated that water may exist as water ice in cold polar regions buried within craters at concentrations of a few wt. % [2]. Infrared images from M3 on Chandrayaan-1 have been interpreted as showing the presence of hydrated surface minerals with the ongoing hydroxyl/water process feeding cold polar traps. This has been supported by observation of ephemeral features termed "space dew" [3]. Meanwhile laboratory studies indicate that water could be present in appreciable quantities in lunar rocks [4] and could also have a cometary source [5]. The presence of sufficient quantities of volatiles could provide a resource which would simplify logistics for long term lunar missions. The European Space Agency (ESA's Directorate of Human Spaceflight and Operations) have provisionally scheduled a robotic mission to demonstrate key technologies to enable later human exploration. Planned for launch in 2018, the primary aim is for precise automated landing, with hazard avoidance, in zones which are almost constantly illuminated (e.g. at the edge of the Shackleton crater at the lunar south pole). These regions would enable the solar powered Lander to survive for long periods > 6 months, but require accurate navigation to within 200m. Although landing in an illuminated area, these regions are close to permanently shadowed volatile rich regions and the analysis of volatiles is a major science objective of the mission. The straw man payload includes provision for a Lunar Volatile and Resources Analysis Package (LVRAP). The authors have been commissioned by ESA to conduct an evaluation of possible technologies to be included in L-VRAP which can be included within the Lander payload. Scientific aims are to demonstrate the extraction of volatiles and determine the volatile inventory of the moon with a view for future In-Situ Resource Utilization (ISRU). Surface samples will be collected by a robotic arm with the possibility of a rover to collect more distant samples. The concentration, chemical and accurate isotopic ratios (D/H, 12C/13C, 15N/14N, 18O/16O and noble gases) of liberated volatiles will be determined, possibly using similar technology to the Philae comet lander of the Rosetta mission [6]. An additional aim is the monitoring of the chemical and isotopic composition of the tenuous lunar atmosphere [7] which will become contaminated by active human exploration. The lunar atmosphere will provide information on the processes involved in forming lunar volatiles and their concentration mechanisms. Modelling the effects of contamination from the Lander is an essential part of this study so that these can be recognized and minimized.

Morse, A. D.; Barber, S. J.; Pillinger, J. M.; Sheridan, S.; Wright, I. P.; Gibson, E. K.; Merrifield, J. A.; Waltham, N. R.; Waugh, L. J.; Pillinger, C. T.

2011-10-01

313

Biosynthesis and Emission of Terpenoid Volatiles from Arabidopsis Flowers  

PubMed Central

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.

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

2003-01-01

314

Volatile organic compound losses from sewage sludge-amended soils  

SciTech Connect

Volatile organic compounds (VOCs) applied to soil in sludge have been assumed to disappear quickly and completely. The VOC behavior in sludge-amended soils has been studied previously only in laboratory systems where the sludged soil has been spiked with compounds of interest. Behavior in these systems may not necessarily represent compound behavior in field soils to which contaminated sludge is added. A series of laboratory microcosm experiments were designed therefore to investigate the behavior of toluene, ethyl benzene, o-, m-, and p-xylene applied to soil in contaminated sludge, and factors influencing loss processes. The VOC loss from sludge-amended soil was well described by a simple one step pseudo-first-order model but in certain soils was better described by a two step first-order model. Volatilization was the predominant loss process. Rates of loss depended on sludge application rate, method of sludge application, soil properties, and on compound characteristics. Experiments indicated that spiking sludge-amended soils gave a reasonable indication of VOC loss rates from systems amended with contaminated sludge at least over a period of 23 d. The majority of VOCs applied to soils in sludge volatilizes quickly to the atmosphere over a few to 10s of days with a small fraction lost more slowly. Potential for VOC crop uptake, livestock ingestion, and contamination of ground water is low under routine, managed applications of sewage sludge to agricultural land.

Wilson, S.C.; Jones, K.C.

1999-08-01

315

Prey and Non-prey Arthropods Sharing a Host Plant: Effects on Induced Volatile Emission and Predator Attraction  

PubMed Central

It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile emissions of lima bean and cucumber plants upon multi-species herbivory by spider mites (Tetranychus urticae) and caterpillars (Spodoptera exigua) in comparison to single-species herbivory. Upon herbivory by single or multiple species, lima bean and cucumber plants emitted volatile blends that comprised mostly the same compounds. To detect additive, synergistic, or antagonistic effects, we compared the multi-species herbivory volatile blend with the sum of the volatile blends induced by each of the herbivore species feeding alone. In lima bean, the majority of compounds were more strongly induced by multi-species herbivory than expected based on the sum of volatile emissions by each of the herbivores separately, potentially caused by synergistic effects. In contrast, in cucumber, two compounds were suppressed by multi-species herbivory, suggesting the potential for antagonistic effects. We also studied the behavioral responses of the predatory mite Phytoseiulus persimilis, a specialized natural enemy of spider mites. Olfactometer experiments showed that P. persimilis preferred volatiles induced by multi-species herbivory to volatiles induced by S. exigua alone or by prey mites alone. We conclude that both lima bean and cucumber plants effectively attract predatory mites upon multi-species herbivory, but the underlying mechanisms appear different between these species.

Hordijk, Cornelis A.; Posthumus, Maarten A.; Dicke, Marcel

2008-01-01

316

Prey and non-prey arthropods sharing a host plant: effects on induced volatile emission and predator attraction.  

PubMed

It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile emissions of lima bean and cucumber plants upon multi-species herbivory by spider mites (Tetranychus urticae) and caterpillars (Spodoptera exigua) in comparison to single-species herbivory. Upon herbivory by single or multiple species, lima bean and cucumber plants emitted volatile blends that comprised mostly the same compounds. To detect additive, synergistic, or antagonistic effects, we compared the multi-species herbivory volatile blend with the sum of the volatile blends induced by each of the herbivore species feeding alone. In lima bean, the majority of compounds were more strongly induced by multi-species herbivory than expected based on the sum of volatile emissions by each of the herbivores separately, potentially caused by synergistic effects. In contrast, in cucumber, two compounds were suppressed by multi-species herbivory, suggesting the potential for antagonistic effects. We also studied the behavioral responses of the predatory mite Phytoseiulus persimilis, a specialized natural enemy of spider mites. Olfactometer experiments showed that P. persimilis preferred volatiles induced by multi-species herbivory to volatiles induced by S. exigua alone or by prey mites alone. We conclude that both lima bean and cucumber plants effectively attract predatory mites upon multi-species herbivory, but the underlying mechanisms appear different between these species. PMID:18185960

de Boer, Jetske G; Hordijk, Cornelis A; Posthumus, Maarten A; Dicke, Marcel

2008-01-10

317

Variation of volatile oil concentration of Mediterranean aromatic shrubs Thymus capitatus hoffmag et link, Satureja thymbra L., Teucrium polium L. and Rosmarinus officinalis  

NASA Astrophysics Data System (ADS)

The volatile oil content of four Labiatae aromatic plants, viz. Thymus capitatus, Satureja thymbra, Teucrium polium and Rosmarinus officinalis has been estimated throughout the year; leaves, braches, flowers and leaf litter were analysed. The pattern of changes in the volatile oil concentration is not the same in all four plants; it corresponds to the major adaptive strategy towards summer drought, which each has evolved.

Vokou, D.; Margaris, N. S.

1986-06-01

318

Direct volatilization of naphthalene to the atmosphere at a phytoremediation site.  

PubMed

Phytoremediation systems are known to reduce groundwater contamination by at least three major mechanisms: plant uptake, phytovolatilization, and enhanced rhizosphere bioremediation. The potential for such systems to enhance a fourth remediation pathway--direct surface volatilization of contaminants through the subsurface and into the atmosphere-has not yet been investigated in the field. A vertical flux chamber was used to measure direct surface volatilization of naphthalene over nine months at a creosote-contaminated site in Oneida, Tennessee, where a phytoremediation system of poplar trees was installed in 1997. A maximum flux of 23 microg m(-2) h(-1) was measured in August 2004, and naphthalene removal by the direct volatilization pathway is estimated to be 50 g yr(-1) at this site. Results suggest that direct volatilization fluxes are most strongly affected by the groundwater level (thickness of the saturated zone), soil moisture, and changes in atmospheric pressure. At this site, transpiration and canopy interception resulting from the phytoremediation system significantly reduce the saturated thickness, increasing the vertical concentration gradient of naphthalene in the groundwater and thus increasing the upward diffusive flux of naphthalene through the subsurface. The presence of the trees, therefore, promotes direct volatilization into the atmosphere. This research represents the first known measurement of naphthalene attenuation by the direct volatilization pathway. PMID:16999140

Marr, Linsey C; Booth, Elizabeth C; Andersen, Rikke G; Widdowson, Mark A; Novak, John T

2006-09-01

319

Volatile-mediated killing of Arabidopsis thaliana by bacteria is mainly due to hydrogen cyanide.  

PubMed

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

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

2010-11-29

320

Herbivore-induced volatiles induce the emission of ethylene in neighboring lima bean plants.  

PubMed

Herbivore attacks induce leaves to emit a specific blend of volatiles. Here we show that exposure to Tetranychus urticae-induced volatiles, as well as T. urticae infestation and artificial wounding, activates the transcription of the genes involved in the biosynthesis of ethylene [S-adenosylmethionine (SAM) synthetase and 1-aminocyclopropane-1-carboxylic acid oxidase] and a gene involved in the biosynthesis of polyamines from SAM (SAM decarboxylase) in lima bean leaves. Moreover, exposure of leaves to any one of the seven major chemical components of T. urticae-induced volatiles also induces expression of these genes. Furthermore, we found that, when lima bean plants were exposed to T. urticae-induced volatiles, they emitted ethylene. Lima bean plants infested by T. urticae and artificially wounded plants also emitted ethylene. Endogenous polyamine levels were not increased in the exposed leaves or the infested leaves, suggesting that polyamine production from SAM was only slightly promoted at the metabolic levels present in the leaves. We found that jasmonate (JA) accumulated in leaves exposed to T. urticae-induced volatiles, and that both JA and salicylate (SA) accumulated in leaves infested by T. urticae. These findings, as well as results of pharmacological analyses, suggest that, in leaves exposed to T. urticae-induced volatiles, ethylene biosynthesis might be regulated by pathways involving JA and the ethylene positive feedback loop. They also suggest that ethylene biosynthesis might be regulated by signaling pathways involving JA, SA and ethylene in T. urticae-infested leaves. PMID:12060229

Arimura, Gen-ichiro; Ozawa, Rika; Nishioka, Takaaki; Boland, Wilhelm; Koch, Thomas; Kühnemann, Frank; Takabayashi, Junji

2002-01-01

321

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

PubMed Central

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.

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

2011-01-01

322

Flower volatiles, crop varieties and bee responses.  

PubMed

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

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

2013-08-20

323

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

PubMed

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

Pino, J A; Marbot, R

2001-12-01

324

Reduction of volatile acidity of acidic wines by immobilized Saccharomyces cerevisiae cells.  

PubMed

Excessive volatile acidity in wines is a major problem and is still prevalent because available solutions are nevertheless unsatisfactory, namely, blending the filter-sterilized acidic wine with other wines of lower volatile acidity or using reverse osmosis. We have previously explored the use of an empirical biological deacidification procedure to lower the acetic acid content of wines. This winemaker's enological practice, which consists in refermentation associated with acetic acid consumption by yeasts, is performed by mixing the acidic wine with freshly crushed grapes, musts, or marc from a finished wine fermentation. We have shown that the commercial strain Saccharomyces cerevisiae S26 is able to decrease the volatile acidity of acidic wines with a volatile acidity higher than 1.44 g?L(-1) acetic acid, with no detrimental impact on wine aroma. In this study, we aimed to optimize the immobilization of S26 cells in alginate beads for the bioreduction of volatile acidity of acidic wines. We found that S26 cells immobilized in double-layer alginate-chitosan beads could reduce the volatile acidity of an acidic wine (1.1 g?L(-1) acetic acid, 12.5 % (v/v) ethanol, pH 3.12) by 28 and 62 % within 72 and 168 h, respectively, associated with a slight decrease in ethanol concentration (0.7 %). Similar volatile acidity removal efficiencies were obtained in medium with high glucose concentration (20 % w/v), indicating that this process may also be useful in the deacidification of grape musts. We, therefore, show that immobilized S. cerevisiae S26 cells in double-layer beads are an efficient alternative to improve the quality of wines with excessive volatile acidity. PMID:23361840

Vilela, A; Schuller, D; Mendes-Faia, A; Côrte-Real, M

2013-01-30

325

DESIGN OF HIGH CURRENT RF ION SOURCE FOR MICROMACHINING APPLICATIONS  

Microsoft Academic Search

Liquid Metal Ion Source (LMIS) and Gas Field Emission Ion Source (GFEIS) are the major ones in micromachining applications so far. They have limitations of contaminations and low throughput. Plasma based ion sources can produce heavier ions for higher throughput, lighter ions for fabrication of higher resolution structures, ions for doping, ion assisted direct writing of metallic, oxide, nitride and

P. Y. Nabhiraj; Ranjini Menon; C. Mallik; R. K. Bhandari

326

Effect of ?-irradiation on volatile compounds of dried Welsh onion (Allium fistulosum L.)  

NASA Astrophysics Data System (ADS)

The volatile compounds of ?-irradiated dried Welsh onion were isolated by simultaneous distillation extraction (SDE) technique and then analyzed by gas chromatography mass spectrometry (GC MS) along with their non-irradiated counterparts. A total of 35 volatile compounds were identified in non-irradiated and 1 kGy irradiated samples and 36 volatile compounds were identified in 3, 5, 10 and 20 kGy irradiated samples so far belong to chemical classes of acid, alcohol, aldehyde, ester, furan, ketone and S-containing compound. S-containing compounds were detected as major volatile compounds of all experimental samples. Though the content of several compounds was increased after irradiation, content of major S-containing compounds was found to decreased in the process. Application of high-dose irradiation if required for microbial decontamination of dried Welsh onion is feasible as it enhanced the total concentration of volatile compounds by 31.60% and 24.85% at 10 and 20 kGy, respectively.

Gyawali, Rajendra; Seo, Hye-Young; Lee, Hyun-Ju; Song, Hyun-Pa; Kim, Dong-Ho; Byun, Myung-Woo; Kim, Kyong-Su

2006-02-01

327

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

PubMed

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

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

328

ION CHROMATOGRAPHY OF ANIONS  

EPA Science Inventory

A Dionex Model 10 Ion Chromatograph was evaluated for the measurement of anionic species in water. The theoretical effect of hydrogen ion activity (pH) on the elution time of phosphate and arsenate was tested and empirical selectivity coefficients were determined for the major pr...

329

Volatile Trapping in Martian Clathrates  

NASA Astrophysics Data System (ADS)

Thermodynamic conditions suggest that clathrates might exist on Mars. Despite observations which show that the dominant condensed phases on the surface of Mars are solid carbon dioxide and water ice, clathrates have been repeatedly proposed to play an important role in the distribution and total inventory of the planet's volatiles. Here we review the potential consequences of the presence of clathrates on Mars. We investigate how clathrates could be a potential source for the claimed existence of atmospheric methane. In this context, plausible clathrate formation processes, either in the close subsurface or at the base of the cryosphere, are reviewed. Mechanisms that would allow for methane release into the atmosphere from an existing clathrate layer are addressed as well. We also discuss the proposed relationship between clathrate formation/dissociation cycles and how potential seasonal variations influence the atmospheric abundances of argon, krypton and xenon. Moreover, we examine several Martian geomorphologic features that could have been generated by the dissociation of extended subsurface clathrate layers. Finally we investigate the future in situ measurements, as well as the theoretical and experimental improvements that will be needed to better understand the influence of clathrates on the evolution of Mars and its atmosphere.

Mousis, Olivier; Chassefière, Eric; Lasue, Jérémie; Chevrier, Vincent; Elwood Madden, Megan E.; Lakhlifi, Azzedine; Lunine, Jonathan I.; Montmessin, Franck; Picaud, Sylvain; Schmidt, Frédéric; Swindle, Timothy D.

2013-01-01

330

Prediction of stream volatilization coefficients  

USGS Publications Warehouse

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.

Rathbun, Ronald, E.

1990-01-01

331

VOLATILIZATION OF ALACHLOR FROM POLYMERIC FORMULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pesticides may be dispersed throughout the environment by several means, including groundwater contamination, surface water contamination, and volatilization with subsequent atmospheric transport. In earlier research primarily directed at reducing the potential for groundwater contamination, a numb...

332

Microbial volatile emissions as insect semiochemicals  

Technology Transfer Automated Retrieval System (TEKTRAN)

We provide a synthesis of the literature describing biochemical interactions between microorganisms and arthropods by way of microbial volatile organic compound (MVOC) production. We explored important metabolic pathways involved in MVOC production and evaluated the functionality, generality, and e...

333

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...

334

Reducing component volatilization in borosilicate glass electromelting  

SciTech Connect

Considerable interest attaches to component volatilization in borosilicate glass melting, and it involves problems in economizing raw materials and in environmental protection. The authors have examined the volatilization kinetics for sodium and boron oxides in the electromelting of alkali borosilicate glass. The experiments show that it is best to use electrical bath furnaces with continuous operation to make small amounts of special glasses instead of crucible, pot, and periodic ones. In making glasses containing boron, one can reduce the volatility considerably by using raw materials containing boron such as calcium borates or borosilicates and increasing the water content of the charge to 10-15%. This reduces the volatilization loss by a factor 3-4 or more by comparison with a batch furnace.

Sobolev, I.A.; Lifanov, F.A.; Stefanovskii, S.V.; Dmitriev, S.A.; Zakharenko, V.N.; Kobelev, A.P.

1987-11-01

335

Hammerstein system represention of financial volatility processes  

NASA Astrophysics Data System (ADS)

We show new modeling aspects of stock return volatility processes, by first representing them through Hammerstein Systems, and by then approximating the observed and transformed dynamics with wavelet-based atomic dictionaries. We thus propose an hybrid statistical methodology for volatility approximation and non-parametric estimation, and aim to use the information embedded in a bank of volatility sources obtained by decomposing the observed signal with multiresolution techniques. Scale dependent information refers both to market activity inherent to different temporally aggregated trading horizons, and to a variable degree of sparsity in representing the signal. A decomposition of the expansion coefficients in least dependent coordinates is then implemented through Independent Component Analysis. Based on the described steps, the features of volatility can be more effectively detected through global and greedy algorithms.

Capobianco, E.

2002-05-01

336

Reactive flash volatilization of fluid fuels  

DOEpatents

The invention provides methods for the production of synthesis gas. More particularly, various embodiments of the invention relate to systems and methods for volatilizing fluid fuel to produce synthesis gas by using a metal catalyst on a solid support matrix.

Schmidt, Lanny D.; Dauenhauer, Paul J.; Dreyer, Bradon J.; Salge, James R.

2013-01-08

337

Sulfur Volatiles in the Early Martian Atmosphere  

NASA Astrophysics Data System (ADS)

Our modeling indicates a high sulfur solubility in martian mantle melts and suggests that sulfur volatile pulses associated with large, discreet volcanic events during the late Noachian may have significantly warmed the atmosphere.

Johnson, S. S.; Zuber, M. T.; Grove, T. L.; Pavlov, A. A.; Mischna, M. A.

2007-03-01

338

Subduction cycling of volatiles and trace elements through the Central American volcanic arc: evidence from melt inclusions  

Microsoft Academic Search

Compositions of melt inclusions in olivine (Fo90-64) from 11 localities in Guatemala, Nicaragua and Cost Rica along the Central American Volcanic Arc are used to constrain combined\\u000a systematics of major and trace elements and volatile components (H2O, S, Cl, F) in parental melts and to estimate volcanic fluxes of volatile elements. The melt inclusions cover the entire\\u000a range of compositions

Seth J. Sadofsky; Maxim Portnyagin; Kaj Hoernle; Paul van den Bogaard

2008-01-01

339

Oxylipin Pathway in the Biosynthesis of Fresh Tomato Volatiles  

Microsoft Academic Search

Fresh tomato volatiles are formed in intact fruit during ripening and upon tissue disruption. There are different pathways involved in the biosynthesis of these volatiles. The oxylipin pathway uses free unsaturated fatty acids with the sequential action of lipoxygenase, hydroperoxide lyase and alcohol dehydrogenase to produce volatile aldehyde and alcohol compounds. Oxylipin volatiles are the most important components in fresh

Emin YILMAZ

340

Determinants of housing price volatility in Canada: a dynamic analysis  

Microsoft Academic Search

This article tries to identify the determinants of housing price volatility and to examine the dynamic effects of these determinants on volatility using quarterly data for Canada. The Generalized Autoregressive Conditional Heteroskedastic (GARCH) and the Vector Autoregressive (VAR) models have been employed to analyse possible time variation of the housing price volatility and the interactions between the volatility and the

Belayet Hossain; Ehsan Latif

2009-01-01

341

Visualization of electrolyte volatile phenomenon in DIR-MCFC  

Microsoft Academic Search

Volatilization of molten salt is one of the factors that control the performance of molten carbonate fuel cells (MCFC). Volatilization of molten salt promotes cross-leakage and the corrosion of metallic components. Moreover, piping blockage is caused by the solidification of volatile matter. Because reforming catalysts filling the anode channel are polluted by molten salt volatile matter in direct internal reforming

Kimihiko Sugiura; Tadakatsu Yodo; Makoto Yamauchi; Kazumi Tanimoto

2006-01-01

342

Experimental investigation of the volatility of elements in respect to temperature and fO2  

NASA Astrophysics Data System (ADS)

The volatility of elements is an important variable during geological processes: its impact ranges from daily out gassing of volcanic vents to catastrophic emissions during volcanic eruptions which might result in global climate change. Volatility played, however, already a major role during the formation of our solar system regarding evaporation and condensation of matter of the solar nebula which finally formed our solar system. Precise knowledge of the parameters controlling volatility as well as condensation of elements is still lacking. We therefore initiated a systematic study of the volatility of 18 volatile elements in respect to oxygen fugacity (fO2) and temperature (T) using a modified mechanically assisted equilibration technique (MAE): Approx. 60 g of haplobasaltic starting composition (An-Di) doped with up to 5000 ppm of volatile element (Li, K, Na, Ti, Cr, Mn, Co, Cu, Cu, Zn, Ga, Rb, Cd, In, Sn, Sb, Cs, Tl) was heated to run temperature. To investigate the fO2 dependence 2 experiments at logfO2 = -11.3 (~ IW -0.5) and - 0,7 (pure air) at constant T (1300 °C) were performed, while T dependence was investigated at 1300 and 1500 °C at constant fO2 in pure air. Two Al2O3 plates extending from the hot spot region up to the upper, cooler regions of the muffle tube were used as condensation traps. The temperature profile of the entire setup including the Al2O3 plates was calibrated prior to any run. Experiments lasted for up two weeks while experimental conditions were kept strictly constant and monitored. Up to 46 samples were taken from the melt by time-series sampling to monitor the loss of volatile elements due to their volatility. In this way both evaporation of the investigated elements as well as their condensation behaviour can be investigated simultaneously. Major element composition was analyzed by electron microprobe analysis, while volatile concentrations were determined by laser- ablation inductively coupled plasma mass spectrometry (LAMS). Preliminary results show a highly complex behaviour of the investigated volatile elements: At low fO2, Li, Na, K, Ti, Cr, Mn, Rb, and Cs show no decrease due to evaporation. At high fO2, however, e.g., Cr and Mn decrease with time due to increased volatility, while Co, Cu, Sb and Tl become less volatile. Due to the relatively small temperature range (200 °C), the observed T effect is small compared to the fO2 dependence: The decrease in elemental concentrations with increasing T stays practically the same for Cr, In, Sn, Sb and Tl. Mn, Cu, Zn, and Ga show a slightly decreased volatility at a higher temperature, while Cs and Cd become slightly more volatile. The present data set indicates a complex behaviour of volatiles due to melt compositional aspects: Concentrations do not generally decrease linearly with time as anticipated earlier, but stay, e.g., constant for some elements due to the formation of stable phases. Additional experiments, however, are necessary to confirm our preliminary findings.

Ertel, W.; Dingwell, D. B.; Pohl, S.

2009-12-01

343

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

SciTech Connect

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).

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

344

Note: Characterization of Yeast Strains on the Basis of Autolytic Activity and Volatile Compounds  

Microsoft Academic Search

Autolytic activity and the production of several major volatile compounds were studied for a set of 18 commercial and non-commercial Saccharomyces cerevisiæ strains isolated from sparkling wine, cider and sherry fermentations. No correlation was found between the autolytic capacity of the strains and isobutanol production levels, in contrast with results published by other authors for a limited number of S.

J. M. Barcenilla; P. J. Martín-Álvarez; A. Vian; R. Gonzalez

2003-01-01

345

Volatile Hydrocarbon Exposure During In Situ Burning of Crude Oil at Sea  

Microsoft Academic Search

Personal exposure of response workers (and other personnel) to volatile hydrocarbons and benzene was monitored as part of the Newfoundland Offshore Burn Experiment (NOBE), a major oil spill combustion trial organized by Environment Canada and sponsored by over 25 governmental and private organizations from Canada and the United States. Benzene and total petroleum hydrocarbons were monitored using organic vapor monitors

Stephen M. Bowes III

1996-01-01

346

Characterisation of thermoset laminates for cosmetic automotive applications: Part II – Cure and residual volatile assessment  

Microsoft Academic Search

This experimental study addresses the critical issues associated with economic manufacturing of high surface quality laminates using a low shrinkage unsaturated polyester with discontinuous, E-glass reinforcement. The objective was to determine the major influences on residual volatiles with a view to reducing their incidence for passenger vehicle applications. A series of plaque mouldings were manufactured using three different initiator systems

Peter J. Schubel; Andrew J. Parsons; Edward H. Lester; Nicholas A. Warrior; Chris D. Rudd

2006-01-01

347

Oral malodor in children and volatile sulfur compound- producing bacteria in saliva: preliminary microbiological investigation  

Microsoft Academic Search

Purpose: This study examined and compared levels of salivary bacteria which produced volatile sulfur compounds (VSC) in young children with and without oral malodor. Methods: Clinic populations of children aged two to seven years, whose parents presented with an unsolicited major complaint of oral malodor in their child (OM+), or aged-matched controls in whom oral malodor was not detected by

Fariba Paryavi-Gholami; Glenn E. Minah; Foo Turng

1999-01-01

348

Application of headspace analysis for the determination of volatile organic compounds in contaminated soils  

Microsoft Academic Search

It has been shown that headspace analysis is more reliable than the purge?and?trap method for the quantification of volatile organic compounds (VOCs) in soil samples. The major shortcoming of the headspace analysis in the case of soil samples is the inability of water to fully extract the soil contaminants. Experiments were conducted to fully understand the limitations and applicability of

S. G. Pavlostathis; G. N. Mathavan

1992-01-01

349

Study on Sources of Volatile Organic Compounds (CMB) in Pearl River Delta region, China  

Microsoft Academic Search

The profiles of major Volatile organic compounds (VOCs) sources including vehicle exhaust, gasoline vapor, painting, asphalt, liquefied petroleum gas (LPG), biomass burning and petrochemical industry in Pearl River Delta were experimentally determined. Source samples were taken by using dilution chamber for mobile and stationary sources, laboratory simulation for biomass burning. The concentrations of 108 VOC species of sources were quantified

Y. Liu; M. Shao; S. Lu; C. Chang; C. J. Wang; B. Wang

2007-01-01

350

Biogenic volatile organic compound emissions from a lowland tropical wet forest in Costa Rica  

Microsoft Academic Search

Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCs) at a lowland tropical wet forest site in Costa Rica. Ten of the species examined emitted substantial quantities of isoprene. These species accounted for 35–50% of the total basal area of old-growth forest on the major edaphic site types, indicating that a high proportion of the

Chris Geron; Alex Guenther; Jim Greenberg; Henry W. Loescher; Deborah Clark; Brad Baker

2002-01-01

351

Reduction of bacterial volatile sulfur compound production by licoricidin and licorisoflavan A from licorice  

Microsoft Academic Search

Halitosis affects a large proportion of the population and is, in most cases, caused by the production of volatile sulfur compounds (VSCs), particularly methyl mercaptan and hydrogen sulfide, by specific bacterial species colonizing the oral cavity. In this study, a supercritical extract of Chinese licorice (Glycyrrhiza uralensis), and its major isoflavans, licoricidin and licorisoflavan A, were investigated for their effect

Shin-ichi Tanabe; Jacynthe Desjardins; Chantal Bergeron; Stefan Gafner; Jacquelyn R Villinski; Daniel Grenier

2012-01-01

352

Have leveraged and traditional ETFs impacted the volatility of real estate stock prices?  

Microsoft Academic Search

Exchange Traded Funds (ETFs), including the innovative leveraged (long and inverse) types, and the ever more creative traditional versions, are accelerating in popularity as preferred investment and trading vehicles. Real estate, a major investment sector, has been made more accessible through these tools. This study investigates if the introduction of real estate ETFs is impacting the volatility of their underlying

Richard J. Curcio; Randy I. Anderson; Hany Guirguis; Vaneesha Boney

2012-01-01

353

Influence of indigenous yeasts on the fermentation and volatile profile of plum brandies  

Microsoft Academic Search

The aim of this study was to determine the influence of different yeasts isolated from fresh blue plum fruits (Aureobasidium sp.) and spontaneously fermenting plum musts (Kloeckera apiculata and Saccharomyces cerevisiae), as well as commercial wine and distillery strains, on the fermentation and chemical composition of plum brandies. Gas chromatography methods were used to detect major volatile components. The most

Pawe? Satora; Tadeusz Tuszy?ski

2010-01-01

354

Functional characterization of enzymes forming volatile esters from strawberry and banana  

Microsoft Academic Search

Volatile esters are flavor components of the majority of fruits. The last step in their biosynthesis is catalyzed by alcohol acyltransferases (AATs), which link alcohols to acyl moieties. Full-length cDNAs putatively encoding AATs were isolated from fruit of wild strawberry (Fragaria vesca) and banana (Musa sapientum) and compared to the previously isolated SAAT gene from the cultivated strawberry (Fragaria x

M. J. Beekwilder; Mayte Alvarez-Huerta; Evert Neef; Francel W. A. Verstappen; Harro J. Bouwmeester; A. Aharoni

2004-01-01

355

Isolation of Crithmum maritimum L. volatile oil by supercritical carbon dioxide extraction and biological assays  

Microsoft Academic Search

The chemical composition of the volatile concentrate obtained by supercritical CO2 extraction of aerial parts of Crithmum maritimum L. growing spontaneously in one area of Mediterranean coast (Buggerru, Sardinia Island, Italy) and in two areas of the Atlantic coast (Figueira da Foz and S. Pedro de Moel, Portugal) was investigated by GC and GC-MS. The major oil components identified were

B. Marongiu; A. Maxia; A. Piras; S. Porcedda; E. Tuveri; M. J. Gonçalves; C. Cavaleiro; L. Salgueiro

2007-01-01

356

Oxidation of diesel-generated volatile organic compounds in the selective catalytic reduction process  

Microsoft Academic Search

The main part of the VOCs (volatile organic compounds) contained in diesel exhaust (â80%) is oxidized to CO and COâ over an SCR (selective catalytic reduction) catalyst. CO is the major product of this oxidation, representing about 50--70% of the formed products (CO + COâ). This preferential formation of CO leads to a pronounced increase of CO emissions when an

M. Koebel; M. Elsener

1998-01-01

357

Ion and neutral mass spectrometry of the isotopic composition of Titan's upper atmosphere: Implications for the atmospheric dynamics and photochemistry, and the evolution of the major species over geological time scales  

NASA Astrophysics Data System (ADS)

The atmosphere of Titan, Saturn's largest moon, is an analog for the Earth's atmosphere in the distant past when life first emerged, and may also be used to study the distant future when the abundance of water in the atmosphere may be reduced by photochemical loss processes associated with climate change. This Dissertation investigates the evolution of Titan's atmosphere utilizing measurements of the stable isotope ratios in molecular nitrogen and methane. The Cassini Ion Neutral Mass Spectrometer (INMS) measures the composition of the ionosphere and neutral atmosphere as it flies through the atmosphere, approaching altitudes as low as 950 km above the surface. INMS measurements of the 14N/15N in N2 as a function of altitude for 30 Titan flybys are compared, using a basic diffusion model, to the Huygens Gas Chromatograph Mass Spectrometer (GCMS) measurement of the 14N/15N in N2 on the surface. This comparison provides the input parameters needed to extrapolate the INMS measurements of 12C/13C in CH4 from the upper atmosphere to the surface where the ratio is within the range of expected primordial values. Although the 12C/13C at Titan is close to the primordial value, escape and photochemistry fractionate the isotope ratio over time. This suggests that methane has been present in Titan's atmosphere for no more than one billion years. A cross-calibration of INMS ion densities with the electron densities measured by the Cassini Radio Plasma Wave Spectrometer (RPWS) constrains the energy response of INMS and provides a new approach for determining the densities of ions in Titan's ionosphere. These ion densities validate an updated coupled Ion-Neutral-Thermal model that constrains the fractionation of the nitrogen isotopes due to photochemistry. Modeling the evolution of the nitrogen isotopes over geological times scales based on chemistry and escape limits the initial 14N/15N to a heavier ratio than the 14N/ 15N observed in the Earth's atmosphere. The methodologies developed for this Dissertation are relevant not only to Titan, but also to Earth. They can be used to evaluate dynamics and photochemistry of the nitrogen isotopes in the upper atmosphere and to define future missions to study the composition of the Earth's thermosphere.

Mandt, Kathleen E.

358

Abstracting connection volatility through tagged futures  

Microsoft Academic Search

The property of connection volatility, fundamental to the ambient intelligence (AmI) domain, makes it bard to develop AmI\\u000a applications. The underlying reason for this is that the code for this concern is scattered and tangled with the core functionality\\u000a of the application. In this paper we introduce the abstraction mechanism for connection volatility that we have created, which\\u000a allows for

Johan Fabry; Carlos Noguera

359

Lévy processes driven by stochastic volatility  

Microsoft Academic Search

In this paper we extend option pricing under Lévy dynamics, by assuming that the volatility of the Lévy process is stochastic.\\u000a We, therefore, develop the analog of the standard stochastic volatility models, when the underlying process is not a standard\\u000a (unit variance) Brownian motion, but rather a standardized Lévy process. We present a methodology that allows one to compute\\u000a option

Kyriakos Chourdakis

2005-01-01

360

Volatiles in Selected Commercial Breads 1  

Microsoft Academic Search

Cereal Chem. 75(6):847-853 Selected types of commercial breads obtained from local markets, in- cluding white sandwich, Irish oatmeal, soft rye, hearty rye, sour dough, home-like white, and onion-basil, were analyzed for volatiles. Using a purge and trap instrument, volatiles were purged directly from fresh crumb and crust samples of each bread type, collected on a trap (Tenax-TA), and transferred to

L. M. Seitz; O. K. Chung; R. Rengarajan

1998-01-01

361

Acute Inhalation Toxicology of Volatile Hydrocarbons  

Microsoft Academic Search

Mice were exposed to various concentrations of volatile hydrocarbons and measurements made of respiratory rate, depth and configuration while the animals were inhaling the agent. Mice were exposed to the volatile hydrocarbons n-pentane, n-hexane, n-heptane or iso-octane. Additional mice were also exposed to the anesthetics diethyl ether or methoxyflurane for comparative purposes. The concentrations used were 1,000; 2,000; 4,000; 8,000;

H. E. SWANN; B. K. KWON; G. K. HOGAN; W. M. SNELLINGS

1974-01-01

362

Mercury volatilization from salt marsh sediments  

Microsoft Academic Search

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

Lora M. Smith; John R. Reinfelder

2009-01-01

363

Volatility, Mortgage Default, and CMBS Subordination  

Microsoft Academic Search

This paper exploits loan-level commercial mortgage data to estimate loan-by-loan implied volatilities of commercial real estate returns, using the Titman and Torous (1989) two-factor contingent-claims mortgage valuation model, and a sample containing all mortgages appearing in 206 public CMBS deals from 1996 through 2005, a total of over 14,000 loans. The implied volatility averages about 20-24% per annum, depending on

Christopher Downing; Richard Stanton; Nancy E. Wallace

2007-01-01

364

Volatile compounds of commercial Milano salami  

Microsoft Academic Search

The relationship between extracted volatiles of Milano salami, one of the main dry-cured sausages produced in Italy, and their olfactory properties was studied. Volatile compounds were extracted by a purge-and-trap method, quantified using a flame ionisation detector and identified by mass spectrometry. Olfactory analysis was performed by sniffing the gas chromatographic effluent. Nearly 80 compounds were identified and quantified: most

A Meynier; E Novelli; R Chizzolini; E Zanardi; G Gandemer

1999-01-01

365

Fat-borne volatiles and sheepmeat odour  

Microsoft Academic Search

The effects of lamb age and diet on volatiles from fat are described. Rendered fat from ram lambs raised on ewe's milk then a corn-based diet was compared with that from lambs raised on milk and a pasture of grass\\/clover, six treatments in all. An additional treatment comprised very old ewes maintained on pasture. Helium-borne volatiles of rendered fat were

O. A. Young; J.-L. Berdagué; C. Viallon; S. Rousset-Akrim; M. Theriez

1997-01-01

366

S&P 100 Index Option Volatility  

Microsoft Academic Search

Using transaction data on the S&P 100 index options, the authors study the effect of valuation simplifications that are commonplace in previous research on the time-series properties of implied market volatility. Using an American-style algorithm that accounts for the discrete nature of the dividends on the S&P 100 index, they find that spurious negative serial correlation in implied volatility changes

Campbell R Harvey; Robert E Whaley

1991-01-01

367

Market volatility modeling for short time window  

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

368

Majority Gate Networks  

Microsoft Academic Search

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

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

1964-01-01

369

Forecasting S&P 100 volatility: the incremental information content of implied volatilities and high-frequency index returns  

Microsoft Academic Search

The information content of implied volatilities and intraday returns is compared, in the context of forecasting index volatility over horizons from 1 to 20 days. Forecasts of two measures of realised volatility are obtained after estimating ARCH models using daily index returns, daily observations of the VIX index of implied volatility and sums of squares of 5-min index returns. The

Bevan J. Blair; Ser-Huang Poon; Stephen J. Taylor

2001-01-01

370

The role of implied volatility in forecasting future realized volatility and jumps in foreign exchange, stock, and bond markets  

Microsoft Academic Search

We study the forecasting of future realized volatility in the foreign exchange, stock, and bond markets from variables in our information set, including implied volatility backed out from option prices. Realized volatility is separated into its continuous and jump components, and the heterogeneous autoregressive (HAR) model is applied with implied volatility as an additional forecasting variable. A vector HAR (VecHAR)

Thomas Busch; Bent Jesper Christensen; Morten Ørregaard Nielsen

2011-01-01

371

Ab initio modelling of volatile fission products in uranium mononitride  

NASA Astrophysics Data System (ADS)

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.

Klipfel, M.; van Uffelen, P.

2012-03-01

372

Measurements of ion concentration in gasoline and diesel engine exhaust  

Microsoft Academic Search

The nanoparticles formed in motor vehicle exhaust have received increasing attention due to their potential adverse health effects. It has been recently proposed that combustion-generated ions may play a critical role in the formation of these volatile nanoparticles. In this paper, we design an experiment to measure the total ion concentration in motor vehicle engine exhaust, and report some preliminary

Fangqun Yu; Thomas Lanni; Brian P. Frank

2004-01-01

373

Adsorption of volatile organic compounds in porous metal–organic frameworks functionalized by polyoxometalates  

Microsoft Academic Search

The functionalization of porous metal–organic frameworks (Cu3(BTC)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 N2 and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies

Feng-Ji Ma; Shu-Xia Liu; Da-Dong Liang; Guo-Jian Ren; Feng Wei; Ya-Guang Chen; Zhong-Min Su

2011-01-01

374

Bacterial volatilization of mercury by immobilized bacteria in fixed and fluidized bed bioreactors  

Microsoft Academic Search

Pseudomonas aeruginosa and Klebsiella pneumoniae, mercury resistant bac- terial strains, which are able to grow at 1200 µM HgCl2 and to reduce mercuric ion to volatile metal mercury, were isolated from hydrocarbons-contaminated river in Morocco. These bacteria were used for removing mercury from synthetic water polluted by mercu- ry using fixed bioreactor and fluidized bed bioreactor. This mercury bio-decontamination system

F. Z. DZAIRI; Y. ZEROUAL; A. MOUTAOUAKKIL; J. TAOUFIK; M. TALBI; M. LOUTFI; K. LEE; M. BLAGHEN

375

Enhanced life ion source for germanium and carbon ion implantation  

NASA Astrophysics Data System (ADS)

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)]. GeF4 and CO2 are commonly used to generate germanium and carbon beams. In the case of GeF4 controlling the tungsten deposition due to the de-composition of WF6 (halogen cycle) is critical to ion source life. With CO2, 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.

Hsieh, Tseh-Jen; Colvin, Neil; Kondratenko, Serguei

2012-11-01

376

Enhanced life ion source for germanium and carbon ion implantation  

SciTech Connect

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.

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

2012-11-06

377

Gas chromatographic analysis of volatiles in fluid and gas inclusions  

USGS Publications Warehouse

Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping. These inclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels. We present here some analyses of inclusions in a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography-mass spectrometry (GC-MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crusing surfaces, and is operated in a pure helium atmosphere at a controlled temperature. Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC-MS. This combination of procedures has been shown to provide geochemically useful information on the process involved in the history of the samples analyzed. ?? 1984.

Andrawes, F.; Holzer, G.; Roedder, E.; Gibson, Jr. , E. K.; Oro, J.

1984-01-01

378

Volatile compounds and antioxidative activity of Porophyllum tagetoides extracts.  

PubMed

Porophyllum tagetoides is an annual warm-weather herb that has an intense typical smell. Its leaves are commonly used in soup preparation and traditional medicine for treatment of inflammatory diseases. Its volatile compounds and antioxidant properties were evaluated in crude, aqueous and ethanol leaf extract and an oil emulsion using different antioxidant assays in vitro, such as: DPPH radical scavenging activity, redox potential, polyphenol content, reducing power and optical density. A high antioxidative activity was found when comparing leaves with stems. The crude extract from leaves showed a very high reducing power (2.88?±?0.20 O.D.) and DPPH radical-scavenging activity (54.63?±?4.80%), in concordance with a major concentration of vitamin C (23.97?±?0.36 mg/100 g). Instead, the highest polyphenol content (264.54?±?2.17 mg GAE/g of sample) and redox potential (561.23?±?0.15 mV) were found by the ethanol and aqueous extract, respectively. Aldehydes and terpenes such as nonanal, decanal, trans-pineno, ?-myrcene and D-limonene were the major volatiles found. This study suggests that Porophyllum tagetoides extracts could be used as antioxidants. PMID:22318745

Jimenez, M; Guzman, A P; Azuara, E; Garcia, O; Mendoza, M R; Beristain, C I

2012-03-01

379

A study of the reactions of H3O+, NO+ and O2+ ions with nine alkoxy alcohols.  

PubMed

Following a selected ion flow tube mass spectrometry (SIFT-MS), analysis of the headspace of a commercial available nail polish remover pad in which gamma-butyrolactone (GBL) and 2-butoxy-1-ethanol were found to be the major volatiles, a study of the reactions of H3O+, NO+ and O2+* ions with nine alkoxy alcohols (R1-O-R2OH) was carried out using selected ion flow tube (SIFT) at a carrier gas (helium) pressure of 9. 3 x 10(1) Pa. Experiments were also performed at various carrier gas pressures (4 x 10(1)-1.1 x 10(2) Pa) for some reactions and under moist air condition. The number and distribution of the hydrates for the product ions were used to identify their structures and to investigate reaction mechanisms. The H3O+ reactions proceed via nascent ion-molecule complex (H3O+ .M)*, then produce R1-O-R2OH. H+, ( R1-O-R2)+, HOR2OH. H+ and R2=O. H+ ions through various channels. Similarly, via a nascent complex (NO+.M)*, NO+. M, (M-H)+ and (M-ROH)+ ions were produced in the NO+ reactions. The collisions between the nascent complexes (H3O+ .M)* and (NO+.M)* with a third body (He, N2 and O2 etc) have influence on the product ion distributions. The O2+ reactions produce mainly dissociative product ions and it is uncertain whether they proceed via the nascent ion-molecule complex (O2+ . M)*. This study provides rate coefficients and product ions in the SIFT-MS database for the analysis of these compounds in normal and humid air samples. It will be further utilised into addiction and drug abuse, respiratory medicine and other research areas using SIFT-MS. PMID:16836154

Wang, Tianshu

2006-04-01

380

Volatiles from Michelia champaca flower: comparative analysis by simultaneous distillation-extraction and solid phase microextraction.  

PubMed

The chemical composition of the volatile compounds isolated by simultaneous distillation-extraction (SDE) and headspace-solid phase microextraction (SPME) from flowers of Michelia champaca growing in Cuba was investigated by GC/FID and GC/MS. Sixty-seven and thirty-four components were identified by SDE and SPME, respectively, with 1,8-cineole (22.8%) as the main constituent in the volatile oil isolated by SDE, and methyl benzoate (30.3%), indole (16.6%) and beta-elemene (10.4%) the major components detected by SPME. PMID:22799101

Báez, Disnelys; Morales, Diego; Pino, Jorge A

2012-05-01

381

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

Microsoft Academic Search

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

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

1997-01-01

382

Degassing of Volatiles and Transport of Semi-Volatile Trace Metals at Piton de la Fournaise - 2007.  

NASA Astrophysics Data System (ADS)

Piton de la Fournaise volcano, Reunion, has been in a state of high eruptive activity since 1998 which culminated in 2007 in its largest eruption since 1931. Olivine-hosted melt inclusions and matrix glasses from this eruption have been analysed for volatiles and trace elements by electron microprobe (S, Cl and F), SIMS (CO2 and H2O) and LA-ICP-MS (Cu, Zn, Pb, Sn, Zr, La, Nb, Ba). The main motivation of this work is to track the degassing processes at this volcano during the large eruption of 2007, and also to investigate further the processes of vapour-melt exchange with respect to other semi volatile elements. The products of this most recent eruption were picrites of transitional (between alkalic and tholeiitic) composition. The major element chemistry is similar to that which has been noted by earlier authors. H2O contents range from 0.08 to 0.81 wt% in melt inclusions with matrix glass representing the degassed portion of melt at 0.09 to 0.16 wt%. S behaves in a similar fashion to H2O ranging from 80- 1107 ppm within melt inclusions and 20-102 ppm in matrix glass. Cl is similar to other measurements at Reunion with 103-306 ppm in MI and a similar 151-262 ppm in the matrix glass showing that little Cl has been lost by degassing. CO2 is high (1117 ppm) in the high water melt inclusions and degasses to lower concentrations (271 ppm) towards low water contents. However, in the matrix glass where the water contents remain low the CO2 contents still range up to 1105 ppm. These elevated CO2 concentrations, in tandem with low concentrations of both S and H2O, require either that magma has been degassed at low pressures and then recirculated to depth (as suggested for Hawaii, for example); or that melts have been degassed by flushing of the magma reservoir with a CO2-rich gas (as proposed on Etna, for example). The behaviour of semi-volatile trace metals in magmatic systems has important implications for both economic and environmental reasons. A CO2-rich fluid has the potential to transport these semi-volatile trace elements by providing a vapour phase into which they partition. As we shall show, the measured variability in semi-volatile trace elements (Pb, Cu, Zn and Sn) compared to the involatile trace elements (Nb, Ba, Zr, La) in Reunion glasses and melt inclusions can best be explained by gas-phase transport processes.

Collins, S. J.; Pyle, D.; Maclennan, J.

2008-12-01

383

The reduction of iron oxides by volatiles in a rotary hearth furnace process: Part III. The simulation of volatile reduction in a multi-layer rotary hearth furnace process  

NASA Astrophysics Data System (ADS)

For reduction of iron oxides by volatiles from coal, the major reductant was found to be H2, and it can affect the overall reduction of iron oxides. In this study, the reduction by actual volatiles of composite pellets at 1000 °C was studied. The volatile reduction of the hand-packed Fe2O3/coal composite pellet as it is devolatilizing out of the pellet was found to be negligible. However, the reduction of iron oxide pellets at the top layer by volatiles from the bottom layers of a three-layer pellet geometry was observed to be about 15 pct. From the morphological observations of partially reduced pellets and the computed rates of bulk mass transfer, volatile reduction appears to be controlled by a mixed-controlled mechanism of bulk gas mass transfer and the limited-mixed control reduction kinetics. Using the reduction rate obtained from the single pellet experiments with pure hydrogen and extrapolating this rate to an H2 partial pressure corresponding to the H2 from the volatiles, an empirical relationship was obtained to approximately predict the amount of volatile reduction up to 20 pct.

Sohn, I.; Fruehan, R. J.

2006-04-01

384

Free and Glycosidically Bound Volatiles of Mentha citrata Ehrh  

Microsoft Academic Search

extract was found. The major components of the essential oil and pentane extract were linalyl acetate (21.46%; 42.02%), linalool (13.68%; 22.66%), 1,8-cineole (12.51%; 6.40%), b-myrcene (8.10%; 2.87%), a-terpineol (7.38%; 0.73%) and geranyl acetate (8.66%; 1.76%). The major components of the volatile aglycones were 1-octen-3-ol (40.28%), eugenol (12.29%), 3-octanol (7.09%), linalool (4.59%), benzyl alcohol (3.71%), 2-phenylethanol (3.67%), 3-hexene-1-ol (2.87%) and 1-heptene-

Josip Masteli; Mladen Milo; Danica Ku

385

Volatility Seminar, Imperial College Some notes on Variance Swaps and Volatility derivatives  

Microsoft Academic Search

We review here the theoretical approaches as well as the practical use of volatility derivatives. Aclear focus will be made on variance swaps, for historical and logical - the most liquid of any volatility instruments - reasons. Instead of going into all the details of the calculations, we will try to point out the useful papers on different subtopics.

Antoine Jacquier

386

Volatility transmission and volatility impulse response func- tions in European electricity forward markets1  

Microsoft Academic Search

Using daily data from March 2001 to June 2005, we estimate a VAR-BEKK model and find evidence of return and volatility spillovers between the German, the Dutch and the British forward electricity markets. We apply Hafner and Herwartz (2006, Journal of International Money and Finance 25, 719-740) Volatility Impulse Response Function (VIRF) to quantify the impact of shock on expected

Yannick Le Pen

2008-01-01

387

Forecasting Realized Volatility Using a Long Memory Stochastic Volatility Model: Estimation, Prediction and Seasonal Adjustment  

Microsoft Academic Search

We study the modeling of large data sets of high frequency returns using a long memory stochastic volatility (LMSV) model. Issues pertaining to estimation and forecasting of large datasets using the LMSV model are studied in detail. Furthermore, a new method of de-seasonalizing the volatility in high frequency data is proposed, that allows for slowly varying seasonality. Using both simulated

Rohit Deo; Clifford Hurvich; Yi Lu

2005-01-01

388

Forecasting Realised Volatility using a Long Memory Stochastic Volatility Model: Estimation, Prediction and Seasonal Adjustment  

Microsoft Academic Search

We study the modelling of large data sets of high frequency returns using a long memory stochastic volatility (LMSV) model. Issues pertaining to estimation and forecasting of datasets using the LMSV model are studied in detail. Furthermore, a new method of de-seasonalising the volatility in high frequency data is proposed, that allows for slowly varying seasonality. Using both simulated as

Clifford Hirvich; Rohit S. Deo; Yi Luo

2003-01-01

389

EDITORIAL: Non-volatile memory based on nanostructures Non-volatile memory based on nanostructures  

NASA Astrophysics Data System (ADS)

Non-volatile memory refers to the crucial ability of computers to store information once the power source has been removed. Traditionally this has been achieved through flash, magnetic computer storage and optical discs, and in the case of very early computers paper tape and punched cards. While computers have advanced considerably from paper and punched card memory devices, there are still limits to current non-volatile memory devices that restrict them to use as secondary storage from which data must be loaded and carefully saved when power is shut off. Denser, faster, low-energy non-volatile memory is highly desired and nanostructures are the critical enabler. This special issue on non-volatile memory based on nanostructures describes some of the new physics and technology that may revolutionise future computers. Phase change random access memory, which exploits the reversible phase change between crystalline and amorphous states, also holds potential for future memory devices. The chalcogenide Ge2Sb2Te5 (GST) is a promising material in this field because it combines a high activation energy for crystallization and a relatively low crystallization temperature, as well as a low melting temperature and low conductivity, which accommodates localized heating. Doping is often used to lower the current required to activate the phase change or 'reset' GST but this often aggravates other problems. Now researchers in Korea report in-depth studies of SiO2-doped GST and identify ways of optimising the material's properties for phase-change random access memory [1]. Resistance switching is an area that has attracted a particularly high level of interest for non-volatile memory technology, and a great deal of research has focused on the potential of TiO2 as a model system in this respect. Researchers at HP labs in the US have made notable progress in this field, and among the work reported in this special issue they describe means to control the switch resistance and show that limiting the current during electroforming leads to the coexistence of two resistance switching modes in TiO2 memristive devices [2]. They also present spectromicroscopic observations and modelling results for the Joule heating during switching, providing insights into the ON/OFF switching process [3]. Researchers in Korea have examined in detail the mechanism of electronic bipolar resistance switching in the Pt/TiO2/Pt structure and show that degradation in switching performance of this system can be explained by the modified distribution of trap densities [4]. The issue also includes studies of TiO2 that demonstrate analog memory, synaptic plasticity, and spike-timing-dependent plasticity functions, work that contributes to the development of neuromorphic devices that have high efficiency and low power consumption [5]. In addition to enabling a wide range of data storage and logic applications, electroresistive non-volatile memories invite us to re-evaluate the long-held paradigms in the condensed matter physics of oxides. In the past three years, much attention has been attracted to polarization-mediated electronic transport [6, 7] and domain wall conduction [8] as the key to the next generation of electronic and spintronic devices based on ferroelectric tunnelling barriers. Typically local probe experiments are performed on an ambient scanning probe microscope platform under conditions of high voltage stresses, conditions highly conducive to electrochemical reactions. Recent experiments [9-13] suggest that ionic motion can heavily contribute to the measured responses and compete with purely physical mechanisms. Electrochemical effects can also be expected in non-ferroelectric materials such as manganites and cobaltites, as well as for thick ferroelectrics under high-field conditions, as in capacitors and tunnelling junctions where the ionic motion could be a major contributor to electric field-induced strain. Such strain, in turn, can affect the effective barrier width in tunnelling experiments, resulting in memristive ionic switching. These phenomena mu

Kalinin, Sergei; Yang, J. Joshua; Demming, Anna

2011-06-01

390

Application of gas chromatography coupled to chemical ionisation mass spectrometry following headspace solid-phase microextraction for the determination of free volatile fatty acids in aqueous samples  

Microsoft Academic Search

Gas chromatography coupled to positive and negative ion chemical ionisation mass spectrometry was evaluated for the determination of free volatile fatty acids (VFAs) from aqueous samples by headspace solid-phase microextraction. Negative ion chemical ionisation in the selected ion monitoring mode using ammonia as reagent gas provided acceptable sensitivity and the highest selectivity for the determination of C2–C7 fatty acids using

M Ábalos; J. M Bayona

2000-01-01

391

Anesthetic action of volatile anesthetics by using Paramecium as a model.  

PubMed

Although empirically well understood in their clinical administration, volatile anesthetics are not yet well comprehended in their mechanism studies. A major conundrum emerging from these studies is that there is no validated model to assess the presumed candidate sites of the anesthetics. We undertook this study to test the hypothesis that the single-celled Paramecium could be anesthetized and served as a model organism in the study of anesthetics. We assessed the motion of Paramecium cells with Expert Vision system and the chemoresponse of Paramecium cells with T-maze assays in the presence of four different volatile anesthetics, including isoflurane, sevoflurane, enflurane and ether. Each of those volatiles was dissolved in buffers to give drug concentrations equal to 0.8, 1.0, and 1.2 EC50, respectively, in clinical practice. We could see that after application of volatile anesthetics, the swimming of the Paramecium cells was accelerated and then suppressed, or even stopped eventually, and the index of the chemoresponse of the Paramecium cells (denoted as I ( che )) was decreased. All of the above impacts were found in a concentration-dependent fashion. The biphasic effects of the clinical concentrations of volatile anesthetics on Paramecium simulated the situation of high species in anesthesia, and the inhibition of the chemoresponse also indicated anesthetized. In conclusion, the findings in our studies suggested that the single-celled Paramecium could be anesthetized with clinical concentrations of volatile anesthetics and therefore be utilized as a model organism to study the mechanisms of volatile anesthetics. PMID:22684567

Zhou, Miaomiao; Xia, Huimin; Xu, Younian; Xin, Naixing; Liu, Jiao; Zhang, Shihai

2012-06-09

392

Ion source  

DOEpatents

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.

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

1984-01-01

393

Volatiles from leaves, fruits, and virgin oil from Olea europaea Cv. Olivastra Seggianese from Italy.  

PubMed

The volatiles produced by leaves and fruits of Olea europaea cv. Olivastra Seggianese have been analyzed in two different phenological stages. Furthermore, the volatiles of the virgin olive oil obtained from ripe fruits has been characterized. The volatiles were sampled by means of two different techniques: hydrodistillation and SPME. Differences were observed between the two different collection times, the different organs, and sampling techniques. The major constituents were often aldehydes, particularly (E)-2-hexenal (9.8-48.0%); however, also many terpenoids have been identified, mainly (E,E)-alpha-farnesene (0.2-27.0%), linalool (0-3.6%), beta-caryophyllene (0-8.1%), and valencene (0-2.5%). This is the first investigation on this cultivar. PMID:12590485

Flamini, Guido; Cioni, Pier Luigi; Morelli, Ivano

2003-02-26

394

Velamo do campo: its volatile constituents, secretory elements, and biological activity.  

PubMed

The volatile components from Croton campestris root bark were localized by an anatomical study and analyzed by gas chromatography-mass spectrometry for the first time. The roots of this plant showed secretory cells. These volatile constituents, isolated from the dichloromethane extract by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. We found 69 components. They were characterized, and the major constituents of crude oil root barks were spathulenol (23.3%) and borneol (18.7%). Growth inhibitory activity of the active compounds in solution was evaluated by measuring minimal inhibitory concentrations using a broth micromethod. The minimal inhibitory concentration of root bark volatile constituents was 1.56 ?g/mL for Staphylococcus aureus, 3.125 ?g/mL for Candida albicans, and 6.25 ?g/mL for Aspergillusniger. PMID:22612296

El Babili, Fatiha; Roques, Christine; Haddioui, Laila; Bellvert, Floriant; Bertrand, Cédric; Chatelain, Christian

2012-05-21

395

Volatile Organic Compound Analysis in Istanbul  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

396

Inhibitory effects of the volatile oils of Callistemon citrinus (Curtis) Skeels and Eucalyptus citriodora Hook (Myrtaceae) on the acetylcholine induced contraction of isolated rat ileum.  

PubMed

Using steam distillation method, the volatile oils of Eucalyptus citriodora and Callistemon citrinus were obtained and their chromatographic profiles examined in hexane: ethylacetate (4:1; 7:3) and hexane-chloroform (7:3). The effects of the volatile oils on acetylcholine (Ach) induced contraction of the rat isolated ileum were investigated based on the ethnomedicinal use of the volatile oil of E. citriodora in treating diarrhoea. Relative to the weight of the fresh leaves (200g in each case), E. citriodora produced 0.75% of the volatile oil while the C. citrinus yielded 0.5%. Combination of hexane-ethylacetate (4:1) gave the best resolution of the constituents as E. citriodora produced six major spots while Callistemon citrinus produced three. The concentration-dependent contractions of the ileum produced by the increasing concentration of the Ach were observed to be remarkably attenuated in the presence of the volatile oils at 5 and 10 mg/ml. At 5mg/ ml, the volatile oils of E. citriodora and C. citrinus independently reduced the Ach maximum contraction to 74.11 ± 12.4 and 19.05 ± 5.17% respectively. At 10mg/ml, the volatile oils further significantly (P<0.05) inhibited the contraction induced by the Ach. The results obtained validated the ethnomedicinal use of the volatile oils particularly that of E. citriodora in reducing ilea contractions occasioned by diarrhoea. However, C. citrinus volatile oil seems to be more effective. PMID:22459474

Adesina, Ayinde Buniyamin; Josephine, Owolabi Omonkhelin

2012-04-01

397

Trophic Complexity and the Adaptive Value of Damage-Induced Plant Volatiles  

PubMed Central

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.

Kaplan, Ian

2012-01-01

398

Volatilization and precipitation of tellurium by aerobic, tellurite-resistant marine microbes.  

PubMed

Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions. PMID:18849455

Ollivier, Patrick R L; Bahrou, Andrew S; Marcus, Sarah; Cox, Talisha; Church, Thomas M; Hanson, Thomas E

2008-10-10

399

Volatilization and Precipitation of Tellurium by Aerobic, Tellurite-Resistant Marine Microbes? †  

PubMed Central

Microbial resistance to tellurite, an oxyanion of tellurium, is widespread in the biosphere, but the geochemical significance of this trait is poorly understood. As some tellurite resistance markers appear to mediate the formation of volatile tellurides, the potential contribution of tellurite-resistant microbial strains to trace element volatilization in salt marsh sediments was evaluated. Microbial strains were isolated aerobically on the basis of tellurite resistance and subsequently examined for their capacity to volatilize tellurium in pure cultures. The tellurite-resistant strains recovered were either yeasts related to marine isolates of Rhodotorula spp. or gram-positive bacteria related to marine strains within the family Bacillaceae based on rRNA gene sequence comparisons. Most strains produced volatile tellurides, primarily dimethyltelluride, though there was a wide range of the types and amounts of species produced. For example, the Rhodotorula spp. produced the greatest quantities and highest diversity of volatile tellurium compounds. All strains also produced methylated sulfur compounds, primarily dimethyldisulfide. Intracellular tellurium precipitates were a major product of tellurite metabolism in all strains tested, with nearly complete recovery of the tellurite initially provided to cultures as a precipitate. Different strains appeared to produce different shapes and sizes of tellurium containing nanostructures. These studies suggest that aerobic marine yeast and Bacillus spp. may play a greater role in trace element biogeochemistry than has been previously assumed, though additional work is needed to further define and quantify their specific contributions.

Ollivier, Patrick R. L.; Bahrou, Andrew S.; Marcus, Sarah; Cox, Talisha; Church, Thomas M.; Hanson, Thomas E.

2008-01-01

400

In situ microbial volatilization of selenium in soils: A case history  

SciTech Connect

A pilot-scale field experiment has been conducted since 1990 to test the effectiveness of microbial volatilization in removing selenium (Se) from soils contaminated with agricultural drainage water. The experiment, in which only irrigation and aeration were employed to enhance microbial processes, was designed to measure all major Se fluxes, including not only selenium loss via volatilization, but also advection with infiltrating rainwater, evapotranspirative transport, and plant uptake. The goal was to account for the total Se mass balance and address questions as to the significance of microbial volatilization relative to other fluxes. Although data collected from 1990 to 1994 showed decreases of Se concentrations in the top soil, subsequent data demonstrated that advective Se fluxes due to rainwater infiltration and evapotranspiration are largely responsible for the observed changes. Se volatilization was measured to account for an annual loss of only about 1%, with volatilization rates decreasing significantly with time, presumably due to the depletion of soil organic carbon. The integrated results of this project demonstrate the advantages and even necessity of an inter-disciplinary and multi-phase approach to evaluating the effectiveness of bioremediation strategies. Extreme caution needs to be taken in interpreting early results; long-term data collection and follow-up are indispensable.

Zawislanski, Peter T.; Benson, Sally M.; Jayaweera, Gamani R.; Wu, L.; Frankenberger, William T.

1999-01-02

401

Comparative study of the volatiles' composition of healthy and larvae-infested Artemisia ordosica.  

PubMed

Volatiles emitted by healthy Artemisia ordosica (Asteraceae) and plants infested with larvae of Sphenoptera sp. (Coleoptera: Buprestidae) or Holcocerus artemisiae (Lepidoptera: Cossidae) were obtained using a dynamic headspace method and analysed by automatic thermal desorption/gas chromatography/mass spectrometry (ATD/GC/MS). Twenty-eight major compounds were identified, and qualitative and quantitative differences were compared. The novel green leaf volatiles 2-hexenal, (Z)-3-hexen-1-ol, 2-hexen-1-ol 1-hexanol, and (Z)-3-hexen-1-ol acetate, the terpenoids alpha-copaene, beta-cedrene, and (E,E)-alpha-farnesene, and the ester methyl salicylate were present in all infested plants. Volatiles from healthy plants were dominated by D-limonene (32.14%), beta-pinene (16.63%), beta-phellandrene (16.06%), and sabinene (12.88%). Volatiles from Sphenoptera sp. larvae-infested plants were dominated by D-limonene (24.74%), beta-pinene (21.05%), alpha-pinene (19.39%), and sabinene (11.64%), whereas volatiles from H. artemisiae larvae-infested plants were dominated by D-limonene (31.76%), sabinene (18.49%), ocimene (15.93%), and beta-phellandrene (10.59%). In addition to the qualitative variation, a larvae-induced quantitative change in the proportion of terpenoids in the blends was also a noticeable feature. PMID:23659167

Zhang, Hui; Zong, Shixiang; Luo, Youqing; Wang, Tao; Wang, Jinlin; Cao, Chuanjian

402

Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing  

SciTech Connect

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gaps exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

403

Contribution of non methane organic volatiles exchange to the carbon budget of isoprene and monoterpene emitting plant species  

NASA Astrophysics Data System (ADS)

Compared to the aerosol fraction, most of the organic carbon present in the atmosphere is found in form of volatile or semivolatile compounds. Vegetation was identified being the major source of these organic volatiles, releasing carbon at the same order of magnitude as the global net biome productivity (NBP). To achieve an estimate of plants carbon exchange, including the emission and deposition of volatile organics, the exchange activity of the two isoprene and monoterpene emitting plant species Quercus robur and Fagus sylvatica was observed under field conditions during the ECHO campaign (Emission and CHemical Transformation of Biogenic Volatile Organic Compounds) in summer 2002 in Jülich, Germany. Primary productivity and VOC exchange was investigated on the branch level by means of a dynamic cuvette system. Organic volatiles were collected on adsorbent tubes and analysed later on by GC-FID and GC-MS for species composition and quantification. Short chain carbonyls were sampled on DNPH coated cartridges and analysed by HPLC-UV. For identification of a broader spectrum of volatile compounds, both methods were complemented by PTR-MS measurements for the isoprene emitting species. Isoprenoid and methanol emissions accounted for the majority of the VOC release, which was partly compensated by the deposition of other oxygenated organic compounds.

Dindorf, T.; Kuhn, U.; Ammann, C.; Neftel, A.; Tritsch, C.; Ciccioli, P.; Koppmann, R.; Kesselmeier, J.

2003-04-01

404

Volatile species retention during metallic fuel casting  

NASA Astrophysics Data System (ADS)

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.

Fielding, Randall S.; Porter, Douglas L.

2013-10-01

405

Characterization of volatiles in unhopped wort.  

PubMed

The volatile fraction of wort components was studied during boiling. Not less than 118 volatile compounds were identified when unhopped pilsner wort was boiled and samples of wort and condensed vapors were analyzed with headspace SPME-GC/MS, of which 54 were confirmed with reference compounds. The wort samples contained 61 identifiable compounds, while the vapor condensate yielded 108 different compounds. Almost 30 known compounds were found that have not been described before in unhopped pilsner wort. One previously unknown aldol reaction product was tentatively identified as 2-phenyl-2-octenal. The detection of branched 2-alkenals underlines the importance of the aldol condensation in Maillard-type reactions, while the tentative identification of alkyloxazoles and alkylthiazoles could once more accentuate the central role of alpha-dicarbonyl compounds, aldehydes, and amino acids in flavor generation. The condensation of wort vapors joined with the SPME-GC/MS technique has proven to be a useful tool in volatile analysis. PMID:18078319

De Schutter, David P; Saison, Daan; Delvaux, Filip; Derdelinckx, Guy; Rock, Jean-Marie; Neven, Hedwig; Delvaux, Freddy R

2007-12-14

406

Mercury volatilization from salt marsh sediments  

NASA Astrophysics Data System (ADS)

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.

Smith, Lora M.; Reinfelder, John R.

2009-06-01

407

Changes in dark chocolate volatiles during storage.  

PubMed

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

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

2012-04-27

408

Mars as a System: The Role of Magmatic Volatiles in the Compositional Modification of the Martian Crust, Surface, and Atmosphere  

NASA Astrophysics Data System (ADS)

Ascending magmas likely played a major role in redistributing material from the martian mantle to the crust, from the crust to the surface, and finally to the atmosphere, particularly during rapid growth of the secondary crust. This redistribution may have involved early loss of dense mineral phases from the magma due to crystal fractionation at the base of the crust and addition of these phases to the deep crust. Further ascent into the crust could have involved loss of magmatic fluids with concomitant addition of volatile components to the crust through fluid/wallrock interaction. As the magma reached the shallow subsurface and surface, reaction of magmatic vapors with surface materials during outgassing would influence how much of the volatile load was actually added to the martian atmosphere and the nature of material added to the surface through vapor/soil interaction and sublimation. The changes in the compositional nature of fluids arising from changes in pressure, temperature, and residual melt composition, likely led to continual modification of the volatile load during magma ascent. Thus, the magmatic contribution to the martian atmosphere may have been quite different than the initial magmatic volatile load. In order to provide first-order constraints on the nature of magmatic volatiles contributed to the evolving early martian atmosphere, a multi-faceted study has been initiated. It integrates (i) experimental mineral/melt phase equilibria for martian magmas (which constrain the nature of minerals left behind and the effect on the magmatic volatile budget), (ii) theoretical and experimental constraints on the compositional nature of exsolved fluids as a function of pressure and temperature (which indicate the nature of volatiles retained to shallow levels), (iii) new experimental data on differential outgassing of magmatic volatiles into an oxidized CO2-rich atmosphere and the nature of sublimates produced, and (iv) sequestration of magmatic volatiles through reaction with surface materials. The predicted coupled effects of these, based on available and new data, will be presented.

Nekvasil, H.; Ustunisik, G. K.

2011-12-01

409

Total volatile flux from Mount Etna  

Microsoft Academic Search

The Total Volatile (TV) flux from Mount Etna volcano has been characterised for the first time, by summing the simultaneously-evaluated fluxes of the three main volcanogenic volatiles: H2O, CO2 and SO2. SO2 flux was determined by routine DOAS traverse measurements, while H2O and CO2 were evaluated by scaling MultiGAS-sensed H2O\\/SO2 and CO2\\/SO2 plume ratios to the UV-sensed SO2 flux. The

A. Aiuppa; G. Giudice; S. Gurrieri; M. Liuzzo; M. Burton; T. Caltabiano; A. J. S. McGonigle; G. Salerno; H. Shinohara; M. Valenza

2008-01-01

410

PROCESS FOR TREATING VOLATILE METAL FLUORIDES  

DOEpatents

This patent relates to the purification of uranium hexafluoride, made by reacting the metal or its tetrafluoride with fluorine, from the frequently contained traces of hydrofluoric acid. According to the present process, UF/sub 6/ containing as an impurity a small amount of hydrofluoric acid, is treated to remove such impurity by contact with an anhydrous alkali metal fluoride such as sodium fluoride. In this way a non-volatile complex containing hydrofluoric acid and the alkali metal fluoride is formed, and the volatile UF /sub 6/ may then be removed by distillation.

Rudge, A.J.; Lowe, A.J.

1957-10-01

411

Dynamical volatilities for yen dollar exchange rates  

NASA Astrophysics Data System (ADS)

We study the continuous time random walk theory from financial tick data of the yen dollar exchange rate transacted at the Japanese financial market. The dynamical behavior of returns and volatilities in this case is particularly treated at the long-time limit. We find that the volatility for prices shows a power-law with anomalous scaling exponents ?=0.92 (1 min) and 0.78 (10 min) and that our behavior occurs in the subdiffusive process. Our result presented will be compared with that of recent numerical calculations.

Yoon, Seong-Min; Choi, J. S.; Christopher Lee, C.; Yum, Myung-Kul; Kim, Kyungsik

2006-01-01

412

Radon as a tracer for lunar volatiles  

NASA Astrophysics Data System (ADS)

Radon and its decay product polonium can be used as tracers to search for lunar volatiles. One effective technique to look for them would be by using alpha-particle spectrometers from lunar orbit. Alpha spectrometers were flown in the Apollo Service Modules during the Apollo 15 and 16 missions, and did observe Rn-222 and its decay product Po-210 on the lunar surface from orbit. This demonstrates that radon and polonium can be observed from orbit; what must next be shown is that such observations can reveal something about the locations of volatiles on the Moon.

Friesen, Larry Jay

413

Source characteristics of oxygenated volatile organic compounds and hydrogen cyanide  

NASA Astrophysics Data System (ADS)

Airborne trace gas measurements from Transport and Chemical Evolution over the Pacific (TRACE-P), Pacific Exploratory Mission (PEM)-Tropics B, and Intercontinental Chemical Transport Experiment-North America (INTEX-NA) experiments are analyzed to examine the major source factors contributing to the observed variabilities of oxygenated volatile organic compounds and cyanides. The positive matrix factorization method is applied to coincident measurements of 11 chemicals including CH3OH, CH3COCH3, CH3CHO, C2H2, C2H6, i-C5H12, CO, CH3Cl, and CHBr3. Measurements of HCN and CH3CN are available for TRACE-P and INTEX-NA. We identify major source contributions from the terrestrial biosphere, biomass burning, industry/urban regions, and oceans. Spatial and back trajectory characteristics of these factors are examined. On the basis of TRACE-P and PEM-Tropics B data, we find a factor that explains 80-88% of the CH3OH variability, 20-40% of CH3COCH3, 7-35% of CH3CHO, and 41% of HCN, most likely representing the emissions from terrestrial biosphere. Our analysis suggested that bi