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Sample records for volatile sulfide avs

  1. Acid volatile sulfide (AVS)- a comment

    NARCIS (Netherlands)

    Meysman, F.J.R.; Middelburg, J.J.

    2005-01-01

    The review by Rickard and Morse (this volume) adequately summarizes our current understanding with respect to acid-volatile sulfides (AVS). At the same time, this review addresses some of the misunderstandings with regard to measurements and dynamics of this important sedimentary sulfur pool. In

  2. Are acid volatile sulfides (AVS) important trace metals sinks in semi-arid mangroves?

    Science.gov (United States)

    Queiroz, Hermano Melo; Nóbrega, Gabriel Nuto; Otero, Xose L; Ferreira, Tiago Osório

    2018-01-01

    Acid-volatile sulfides (AVS) formation and its role on trace metals bioavailability were studied in semi-arid mangroves. The semi-arid climatic conditions at the studied sites, marked by low rainfall and high evapotranspiration rates, clearly limited the AVS formation (AVS contents varied from 0.10 to 2.34μmolg -1 ) by favoring oxic conditions (Eh>+350mV). The AVS contents were strongly correlated with reactive iron and organic carbon (r=0.84; r=0.83 respectively), evidencing their dominant role for AVS formation under semi-arid conditions. On the other hand, the recorded ΣSEM/AVS values remained >1 evidencing a little control of AVS over the bioavailability of trace metals and, thus, its minor role as a sink for toxic metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Influence of commercial (Fluka) naphthenic acids on acid volatile sulfide (AVS) production and divalent metal precipitation.

    Science.gov (United States)

    McQueen, Andrew D; Kinley, Ciera M; Rodgers, John H; Friesen, Vanessa; Bergsveinson, Jordyn; Haakensen, Monique C

    2016-12-01

    Energy-derived waters containing naphthenic acids (NAs) are complex mixtures often comprising a suite of potentially problematic constituents (e.g. organics, metals, and metalloids) that need treatment prior to beneficial use, including release to receiving aquatic systems. It has previously been suggested that NAs can have biostatic or biocidal properties that could inhibit microbially driven processes (e.g. dissimilatory sulfate reduction) used to transfer or transform metals in passive treatment systems (i.e. constructed wetlands). The overall objective of this study was to measure the effects of a commercially available (Fluka) NA on sulfate-reducing bacteria (SRB), production of sulfides (as acid-volatile sulfides [AVS]), and precipitation of divalent metals (i.e. Cu, Ni, Zn). These endpoints were assessed following 21-d aqueous exposures of NAs using bench-scale reactors. After 21-days, AVS molar concentrations were not statistically different (pAVS production was sufficient in all NA treatments to achieve ∑SEM:AVS AVS) could be used to treat metals occurring in NAs affected waters. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Spatial and seasonal variations of Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metals (SEM) in Dutch marine and freshwater sediments

    NARCIS (Netherlands)

    van den Hoop MAGT; den Hollander HA; Kerdijk HN; LAC; ECO; Delft Hydraulics

    1995-01-01

    In het kader van het project Exposure Assessment zijn Acid Volatile Sulfide (AVS) en Simultaneously Extracted Metal (SEM) gehalten bepaald in een aantal mariene en zoetwater sedimenten. AVS-gehalten varieren van niet aantoonbaar (<0.1) tot ongeveer 50 notmol per gram droog sediment. In het

  5. Spatial and seasonal variations of Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metals (SEM) in Dutch marine and freshwater sediments

    NARCIS (Netherlands)

    Hoop MAGT van den; Hollander HA den; Kerdijk HN; LAC; ECO; Delft Hydraulics

    1995-01-01

    Within the framework of the project Exposure Assessment, Acid Volatile Sulfide (AVS) and Simultaneously Extracted Metal (SEM) contents of Dutch marine and freshwater sediments were determined. For the present set of fifteen marine and six freshwater sediments AVS levels vary between non-detectable

  6. The relation between Acid Volatile Sulfides (AVS) and metal accumulation in aquatic invertebrates: implications of feeding behavior and ecology.

    Science.gov (United States)

    De Jonge, Maarten; Blust, Ronny; Bervoets, Lieven

    2010-05-01

    The present study evaluates the relationship between Acid Volatile Sulfides (AVS) and metal accumulation in invertebrates with different feeding behavior and ecological preferences. Natural sediments, pore water and surface water, together with benthic and epibenthic invertebrates were sampled at 28 Flemish lowland rivers. Different metals as well as metal binding sediment characteristics including AVS were measured and multiple regression was used to study their relationship with accumulated metals in the invertebrates taxa. Bioaccumulation in the benthic taxa was primarily influenced by total metal concentrations in the sediment. Regarding the epibenthic taxa metal accumulation was mostly explained by the more bioavailable metal fractions in both the sediment and the water. AVS concentrations were generally better correlated with metal accumulation in the epibenthic invertebrates, rather than with the benthic taxa. Our results indicated that the relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology. Copyright 2010 Elsevier Ltd. All rights reserved.

  7. The relation between Acid Volatile Sulfides (AVS) and metal accumulation in aquatic invertebrates: Implications of feeding behavior and ecology

    International Nuclear Information System (INIS)

    De Jonge, Maarten; Blust, Ronny; Bervoets, Lieven

    2010-01-01

    The present study evaluates the relationship between Acid Volatile Sulfides (AVS) and metal accumulation in invertebrates with different feeding behavior and ecological preferences. Natural sediments, pore water and surface water, together with benthic and epibenthic invertebrates were sampled at 28 Flemish lowland rivers. Different metals as well as metal binding sediment characteristics including AVS were measured and multiple regression was used to study their relationship with accumulated metals in the invertebrates taxa. Bioaccumulation in the benthic taxa was primarily influenced by total metal concentrations in the sediment. Regarding the epibenthic taxa metal accumulation was mostly explained by the more bioavailable metal fractions in both the sediment and the water. AVS concentrations were generally better correlated with metal accumulation in the epibenthic invertebrates, rather than with the benthic taxa. Our results indicated that the relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology. - The relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology.

  8. Do acid volatile sulfides (AVS) influence the accumulation of sediment-bound metals to benthic invertebrates under natural field conditions?

    Science.gov (United States)

    De Jonge, Maarten; Dreesen, Freja; De Paepe, Josefina; Blust, Ronny; Bervoets, Lieven

    2009-06-15

    The present study evaluates the influence of acid volatile sulfides (AVS) on accumulation of sediment-bound metals in benthic invertebrates under natural field conditions. Natural sediments, pore water, surface water, and two species of widespread benthic invertebrates (Chironomus gr. thummi and Tubifex tubifex) were collected from 17 historical polluted Flemish lowland rivers and measured for metal concentrations. Different sediment characteristics were determined (AVS, organic matter, clay content) and multiple regression was used to study their relationship with accumulated metals in the invertebrates. Physical and chemical analysis of the field samples indicated low metal concentrations in the water and pore water, but very high metal concentrations in the sediment and the invertebrates, especially for Pb (5.99 micromol/ g). In general, metal accumulation in chironomids and tubificid worms was most strongly correlated with total metal concentrations in the sediment and sediment metal concentrations normalized for organic matter and clay content. Following the results of the linear regression model, AVS did not turn out to be a significant variable in describing variation in metal accumulation. Our study clearly demonstrates that, in addition to the results gained from experiments under lab conditions, benthic invertebrates can accumulate metals from unspiked field sediments even when there's an excess of AVS.

  9. A comparison of sediment quality results with acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) ratio in Vojvodina (Serbia) sediments.

    Science.gov (United States)

    Prica, M; Dalmacija, B; Roncević, S; Krcmar, D; Becelić, M

    2008-01-25

    The acid-volatile sulfide (AVS), simultaneously extracted metals (SEM), total metals, and pore-water metal concentrations were studied in Vojvodina (Serbia) sediments. In Serbia, there are no regulations concerning sediment quality standards and sediment management. Harmonization of legislation in the domain of environmental protection with EU requirements will increase the significance of the sediment issue. Sediment quality was assessed according to Dutch standards, but the results were also compared with Canadian and USEPA (United States Environmental Protection Agency) guidelines for sediment quality. A comparison of the results based on different criteria for sediment quality assessment shows that they are sometimes contradictory. Therefore, a single approach to quality assessment may be insufficient. The Sigma[SEM]/[AVS] ratio was found to be greater than one at several locations that were already recognized as places of high risk based on Dutch standards. Some other samples had Sigma[SEM]/[AVS]AVS]>1 can cause increased toxicity because there are many other metal-binding phases in sediments. Metals that are associated with AVS may be released within sediments through storms, dredging activities, oxidation, etc., and may have adverse environmental impacts. This has to be taken into account during dredging, which is for some sediments necessary because the sediment is of class 4 (Dutch evaluation), because the dredging process will certainly increase the concentration of bioavailable heavy metals and disturb the sedimentation dynamics. The obtained results will be invaluable for future activities regarding dredging and sediment management in the country.

  10. Risk assessment of heavy metals in Vembanad Lake sediments (south-west coast of India), based on acid-volatile sulfide (AVS)-simultaneously extracted metal (SEM) approach.

    Science.gov (United States)

    Shyleshchandran, Mohanachandran Nair; Mohan, Mahesh; Ramasamy, Eswara Venkatesaperumal

    2018-03-01

    Contamination of estuarine system due to heavy metals is a severe issue in tropical countries, especially in India. For the evaluation of the risk due to heavy metals, the current study assessed spatial and temporal variation of acid-volatile sulfide (AVS), simultaneously extracted metal (SEM), and total metal concentration as toxicity indicator of aquatic sediments in Vembanad Lake System (VLS), India. Surface sediment samples collected from 12 locations from the northern portion of VLS for 4 years during different seasons. The results suggest, in post-monsoon season, 91% of the sampling locations possessed high bioavailability of metals and results in toxicity to aquatic biota. The average seasonal distribution of SEM during the period of observations was in the order post-monsoon > pre-monsoon > monsoon (1.76 ± 2.00 > 1.35 ± 0.60 > 0.80 ± 0.54 μmol/g). The concentration of individual metals on ∑SEM are in the order SEM Zn > SEM Cu> SEM Cd ≈ SEM Pb > SEM Hg. Considering annual ΣSEM/AVS ratio, 83% of the sites cross the critical value of 'One,' reveals that active sulfide phase of the sediment for fixing the metals is saturated. The molar ratio (differences between SEM and AVS) and its normalized organic carbon ratio reveals that in the post-monsoon season, about 42% of the sites are in the category of adverse effects are possible. The study suggests the toxicity and mobility of the metals largely depend on the available AVS, and the current situation may pose harm to benthic organisms.

  11. Bioavailability assessment of toxic metals using the technique "acid-volatile sulfide (AVS)-simultaneously extracted metals (SEM)" in marine sediments collected in Todos os Santos Bay, Brazil.

    Science.gov (United States)

    Silva, Jucelino B; Nascimento, Rodrigo A; de Oliva, Sergio T; de Oliveira, Olívia M C; Ferreira, Sergio L C

    2015-10-01

    This paper reports the bioavailability of the metals (cadmium, copper, zinc, lead, and nickel) in sediment samples collected in seven stations from the São Paulo Estuary, Todos os Santos Bay, Brazil. The bioavailability was determined by employing the technique "acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM)". The elements cadmium, copper, lead, and zinc were determined using differential pulse anodic stripping voltammetry (DPASV), while nickel was quantified utilizing electrothermal atomic absorption spectrometry (ET AAS). The accuracy of these methods was confirmed using a certified reference material of estuarine sediment (NIST 1646). The sulfide was quantified using potentiometry with selective electrode and the organic matter determination employing an indirect volumetric method using potassium dichromate and iron(II) sulfate solutions. The bioavailability of the metals was estimated by relationship between the concentration of AVS and the sum of the concentrations of the simultaneously extracted metals (ΣSEM), considering a significant toxicity when (ΣSEM)/(AVS) is higher than 1. The bioavailability values in the seven stations studied varied from 0.93 to 1.31 (June, 2014) and from 0.34 to 0.58 (September, 2014). These results demonstrated a critical condition of toxicity (bioavailability >1) in six of the seven sediment samples collected during the rainy season (June, 2014). In the other period (September, 2014), the bioavailability was always lower than 1 for all sediment samples collected in the seven stations. The individual values of the concentrations of the five metals were compared with the parameters PEL (probable effects level) and TEL (threshold effects level), which are commonly employed for characterization of ecological risk in environmental systems. This comparison revealed that all metals have concentrations lower than the PEL and only zinc and lead in some stations have contents higher than the TEL. The

  12. Acid Volatile Sulfides (avs) and the Bioavailability of Trace Metals in the Channel of the SÃO Francisco River, Sepetiba Bay - de Janeiro-Brazil

    Science.gov (United States)

    Monte, Christiane; Rodrigues, Ana Paula; Marinho, Matheus; Quaresma, Tássia; Machado, Wilson

    2014-05-01

    Sepetiba Bay has 430 Km2 of internal and 2,500 Km2 area of the drainage basin (Lacerda et al., 2007), located 60 km west of the city of Rio de Janeiro. Sepetiba Bay has 430 Km2 of internal and 2,500 Km2 area of the drainage basin (Lacerda et al., 2007), located 60 km west of the city of Rio de Janeiro.The San Francisco channel comes from the Guandu River and empties into Sepetiba Bay and is the main contributor of freshwater to the estuarine system. The Guandu River system/channel of San Francisco receives contribution of domestic and industrial effluents, which go largely to Sepetiba Bay. This work aimed to evaluate the .This work aimed to evaluate the ratio SEM/AVS as a way of predicting bioavailability trace metals from industrial sewage, mainly, in the estuarine system of Sepetiba. This model is based on the property of some Divalent metal cations (Cd, Cu, Ni, Pb and Zn), by presenting a low solubility constant, are removed from the soluble fraction by precipitation, forming secondary metal sulfides. Were held four transects, made up of three points each, the coast line to the center of the Bay. The surface sediment was collected with a van Veen sampler type ,packed in glass jars and kept frozen until analysis.The determination of SEM/AVS followed the methodology described by Allen et al. (1991). The variation between sulfide 159.88 ± 0.05 µmol/g on 12 points. The metals that entered the sum of simultaneous extraction were: Cd, Cu, Ni, Pb and Zn ranging from: 6.47 ± 0.11 µmol/g on sum.The means (± standard deviation) ratio SEM/AVS per transect were: 1.04 ± 1.20 (transect 1); 0.48 ± 0.53 (transect 2); 1.26 ± 1.32 (transect 3) and 0.18 ± 0.14 (transect 4). Only transects 1 and 3 had higher results than 1 , meaning that there are more divalent metal sulfides in the environment. This means that only the sulfides would not be capable of complex and may reflect the potential bioavailability of these in the aquatic environment. There is no statistical

  13. Spatial variation of metals and acid volatile sulfide in floodplain lake sediment

    NARCIS (Netherlands)

    Griethuysen, van C.; Meijboom, E.W.; Koelmans, A.A.

    2003-01-01

    In risk assessment of aquatic sediments, much attention is paid to the immobilizing effect of acid volatile sulfide (AVS) on trace metals. The difference of AVS and simultaneously extracted metals (SEM) gives an indication of metal availability. In floodplain sediments, where changing redox

  14. A kinetic approach to evaluate the association of acid volatile sulfide and simultaneously extracted metals in aquatic sediments

    NARCIS (Netherlands)

    Poot, A.; Meerman, E.; Gillissen, F.; Koelmans, A.A.

    2009-01-01

    The acid volatile sulfide (AVS) and simultaneously extracted metals (¿SEM) method is widely used for evaluating potential bioavailability of heavy metals in soil and sediment. It is also criticized, because the requirement that AVS and SEM metals (i.e., Cd, Cu, Ni, Pb, and Zn) are associated in the

  15. Aplicação de planejamento fatorial a protocolo de extração e fixação de sulfetos volatilizáveis por acidificação (SVA em amostras de sedimento Factorial design used on the extraction and fixation of acid volatile sulfides (AVS from sediment samples

    Directory of Open Access Journals (Sweden)

    Danielle Caroline Schnitzler

    2009-01-01

    Full Text Available The AVS is defined operationally as acid volatile sulfide, which is a controlling phase on the partition of some metallic species in sediments. A Factorial design was evaluated by means of 16 experiments and using four variables: temperature, extraction time, N2 flow, and volume of the S2- collection solution. The factors that contributed to the efficiency of the process were the extraction time and the N2 flow. Trapping of S2- was efficient in AAB. The S2- was quantified using a potentiometric procedure. Recovery tests for S2- concentrations varying from 1×10-5 to 1×10-4 mol L-1 were in the range from 93 to 116%.

  16. Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata

    Science.gov (United States)

    Lee, J.-S.; Lee, B.-G.; Yoo, H.; Koh, C.-H.; Luoma, S.N.

    2001-01-01

    A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30 ??mol g-1), but with constant Ag, Cd, and Zn concentrations of 0.1, 0.1 and 7 ??mol g-1, respectively. The sediments were supplemented with contaminated food (TetraMin??) containing 3 levels of Ag-Cd-Zn (uncontaminated, 1?? or 5??1 metal concentrations in the contaminated sediment). The results suggest that bioaccumulation of Ag, Cd and Zn in the worms occurred predominantly from ingestion of contaminated sediments and contaminated supplementary food. AVS or dissolved metals (in porewater and overlying water) had a minor effect on bioaccumulation of the 3 metals in most of the treatments. The contribution to uptake from the dissolved source was most important in the most oxic sediments, with maximum contributions of 8% for Ag, 30% for Cd and 20% for Zn bioaccumulation. Sediment bioassays where uncontaminated supplemental food is added could seriously underestimate metal exposures in an equilibrated system; N. arenaceodentata feeding on uncontaminated food would be exposed to 40-60% less metal than if the food source was equilibrated (as occurs in nature). Overall, the results show that pathways of metal exposure are dynamically linked in contaminated sediments and shift as external geochemical characteristics and internal biological attributes vary.

  17. Assessing pollution in a Mediterranean lagoon using acid volatile sulfides and estimations of simultaneously extracted metals.

    Science.gov (United States)

    Zaaboub, Noureddine; Helali, Mohamed Amine; Martins, Maria Virgínia Alves; Ennouri, Rym; Béjaoui, Béchir; da Silva, Eduardo Ferreira; El Bour, Monia; Aleya, Lotfi

    2016-11-01

    Bizerte Lagoon is a southern Mediterranean semi-enclosed lagoon with a maximum depth of 12 m. After assessing sediment quality, the authors report on the physicochemical characteristics of the lagoon's surface sediment using SEM (simultaneously extracted metals) and AVS (acid volatile sulfides) as proxies. Biogeochemical tools are used to investigate the environmental disturbance at the water-sediment interface by means of SEM and AVS to seek conclusions concerning the study area's pollution status. Results confirm accumulation of trace elements in sediment. The use of the SEM-AVS model with organic matter in sediment (ƒOC) confirms possible bioavailability of accumulated trace elements, especially Zn, in the southern part of the lagoon, with organic matter playing an important role in SEM excess correction to affirm a nontoxic total metal sediment state. Individual trace element toxicity is dependent on the bioavailable fraction of SEM Metal on sediment, as is the influence of lagoon inflow from southern water sources on element bioavailability. Appropriate management strategies are highly recommended to mitigate any potential harmful effects on health from this heavy-metal-based pollution.

  18. Spatial variation of acid-volatile sulfide and simultaneously extracted metals in Egyptian Mediterranean Sea lagoon sediments.

    Science.gov (United States)

    Younis, Alaa M; El-Zokm, Gehan M; Okbah, Mohamed A

    2014-06-01

    In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0-20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu + Zn + Cd + Pb + Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn > Cu > Ni > Pb > Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS > 1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.

  19. Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California.

    Science.gov (United States)

    Reese, Brandi Kiel; Anderson, Michael A; Amrhein, Christopher

    2008-11-15

    The Salton Sea is a large shallow saline lake located in southern California that is noted for high sulfate concentrations, substantial algal productivity, and very warm water column temperatures. These conditions are well-suited for sulfide production, and sulfide has been implicated in summer fish kills, although no studies have been conducted to specifically understand hydrogen sulfide production and volatilization there. Despite polymictic mixing patterns and relatively short accumulation periods, the amount of sulfide produced is comparable to meromictic lakes. Sulfide levels in the Salton Sea reached concentrations of 1.2 mmol L(-1) of total free sulfide in the hypolimnion and 5.6 mmol L(-1) in the sediment pore water. Strong winds in late July mixed H2S into the surface water, where it depleted the entire water column of dissolved oxygen and reached a concentration of 0.1 mmol L(-1). Sulfide concentrations exceeded the toxicity threshold of tilapia (Oreochromis mossambicus) and combined with strong anoxia throughout the water column, resulted in a massive fish kill. The mixing of sulfide into the surface waters also increased atmospheric H2S concentrations, reaching 1.0 micromol m(-3). The flux of sulfide from the sediment into the water column was estimated to range from 2-3 mmol m(-2) day(-1) during the winter and up to 8 mmol m(-2) day(-1) during the summer. Application of the two-layer model for volatilization indicates that up to 19 mmol m(-2) day(-1) volatilized from the surface during the mixing event. We estimate that as much as 3400 Mg year(-1) or approximately 26% of sulfide that diffused into the water column from the deepest sediments may have been volatilized to the atmosphere.

  20. Volatile Organic Sulfur Compounds of Environmental Interest: Dimethyl Sulfide and Methanethiol

    Science.gov (United States)

    Chasteen, Thomas G.; Bentley, Ronald

    2004-01-01

    Volatile organic sulfur compounds (VOSCs) have been assigned environmental roles in global warming, acid precipitation, and cloud formation where two important members dimethyl sulfide (CH3)2 S, DMS, and methanethiol, CH3SH, MT, of VOSC group are involved.

  1. Temporal dynamics of AVS and SEM in sediment of shallow freshwater floodplain lakes

    NARCIS (Netherlands)

    Griethuysen, van C.; Lange, de H.J.; Heuij, van der M.; Bies, S.C.; Gillissen, F.; Koelmans, A.A.

    2006-01-01

    Acid volatile sulfide (AVS) is an operationally defined sulfide fraction, which is considered important for trace metal fate in reduced sediments. Understanding AVS formation rates is important for the management of metal polluted sediment. However, little lis known about the fate and dynamics of

  2. Distribution of Alkalis (Na, Cs, Rb) Between Silicate and Sulfide: Implications for Planetary Volatile Depletion

    Science.gov (United States)

    Boujibar, A.; Fei, Y.; Righter, K.; Du, Z.; Bullock, E.

    2018-01-01

    The abundances of volatile elements in the Earth's mantle are correlated with their temperatures of condensation. This depletion can be due to either incomplete condensation of the elements during the nebula condensation or evaporation processes during planetary growth. Elements that have affinities with metals (siderophile) and sulfides (chalcophile) are additionally depleted due to their segregation into the core. Therefore, study of lithophile elements could be useful to isolate processes of volatilization and their effect on the abundance of the elements in the Earth's mantle. However, the correlation of these lithophile elements including alkali elements, with their temperatures of condensation shows a significant scatter, which is difficult to reconcile with a depletion by vaporization or incomplete condensation alone.

  3. Acid Volatile Sulfide (AVS) als instrument bij de risicobeoordeling van waterbodems

    NARCIS (Netherlands)

    Hoop MAGT van den; Peijnenburg WJGM; Sijm DTHM; Berg GA van den; Heijdt LM van der; Zwolsman JJG; Rijksinstituut voor Integraal; LAC; ECO; CSR

    2000-01-01

    Risk assessment of sediments is primarily based on the determination of total content of polluted components. Analysis of sediment composition in the Netherlands, both at present and expected in the future, shows that heavy metals, especially Zn, Cu and Ni, appear to be the main compounds

  4. Acid Volatile Sulfide (AVS) als instrument bij de risicobeoordeling van waterbodems

    NARCIS (Netherlands)

    van den Hoop MAGT; Peijnenburg WJGM; Sijm DTHM; van den Berg GA; van der Heijdt LM; Zwolsman JJG; LAC; ECO; CSR

    2000-01-01

    Een analyse van de huidige en de in de toekomst te verwachten kwaliteit van Nederlandse sedimenten laat zien dat vooral Zn, Cu and Ni de stoffen zullen zijn die in belangrijke mate de verontreinigingsgraad zullen gaan bepalen. De mobiliteit van deze elementen wordt sterk gereduceerd door de

  5. Acid-volatile sulfide and simultaneously extracted metals in surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea: concentrations, spatial distributions and the indication of heavy metal pollution status.

    Science.gov (United States)

    Zhuang, Wen; Gao, Xuelu

    2013-11-15

    Surface sediments were collected from the coastal waters of southwestern Laizhou Bay and the rivers it connects with during summer and autumn 2012. The acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) were measured to assess the sediment quality. The results showed that not all sediments with [SEM]-[AVS]>0 were capable of causing toxicity because the organic carbon is also an important metal-binding phase in sediments. Suppose the sediments had not been disturbed and the criteria of US Environmental Protection Agency had been followed, heavy metals in this area had no adverse biological effects in both seasons except for few riverine samples. The major ingredient of SEM was Zn, whereas the contribution of Cd - the most toxic metal studied - to SEM was <1%. The distributions of AVS and SEM in riverine sediments were more easily affected by anthropogenic activity compared with those in marine sediments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Emissions of volatile hydrocarbons (VOC) during drying of sawdust; Utslaepp av laettflyktiga kolvaeten vid torkning av biobraenslen

    Energy Technology Data Exchange (ETDEWEB)

    Granstroem, Karin

    2001-08-01

    In the project 'Emissions of volatile hydrocarbons (VOC) during drying of sawdust' the identity, amount and composition of monoterpenes found in the drying medium of a fluidized bed drier drying sawdust from Norwegian spruce and Scotch pine has been determined. The energy efficiency of the drier has also been measured. The aim of this project was to reduce both emissions and energy required for drying, to minimize environmental and health hazards, and make drying more competitive. This would help our primary target group - small scale saw mills - to make use of the sawdust produced as a by- product by making pellets and briquettes. If the VOC remains in the sawdust its energy content will improve and therefore also its value as a fuel. The sawdust was dried to different moisture levels in a spouted bed drier at atmospheric pressure, using either recirculating or not recirculating drying medium with temperatures 140, 170 or 200 deg C. The emissions of VOC were measured using a flame ionization detector (FID) and the nature of the emissions analyzed with a gas chromatograph with mass spectrometric detector (GC-MS). The GC-MS data is reported as emitted substance per oven dry weight (odw). Experiments show that terpenes do not leave the sawdust in great amounts until it is dried to a moisture content (water/total weight) below 10%. When sawdust is dried to a predetermined moisture level, the terpene emissions increase when warmer incoming drying medium is used. The monoterpenes found in greatest amount are a-pinene, b-pinene, 3-carene, limonene and myrcene. y-terpinene was detected in emissions from pine but not from spruce. The relative amounts of different monoterpenes did not vary significantly with post-drying moisture content, but drying medium of higher temperature caused an increase in the relative amount of less volatile monoterpenes. The FID data is reported as concentration of VOC in the drying medium, and as weight VOC per odw. The concentration

  7. Heavy metal speciation in solid-phase materials from a bacterial sulfate reducing bioreactor using sequential extraction procedure combined with acid volatile sulfide analysis.

    Science.gov (United States)

    Jong, Tony; Parry, David L

    2004-04-01

    Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be

  8. Na, Rb and Cs partitioning between metal, silicate and sulfide: Implications for volatile depletion in terrestrial planets

    Science.gov (United States)

    Boujibar, A.; Fei, Y.; Du, Z.; Righter, K.; Bullock, E. S.

    2017-12-01

    Inner Solar System materials are known for their depletion in volatile elements, including the moderately volatile alkalis: Na, K, Rb, and Cs. The origin of this depletion is still uncertain, as several processes could have been involved, during the nebular condensation or planetary accretion. Volatile depletion is commonly estimated through comparison of alkali concentrations relatively to those of chondrites, assuming they remain in planetary mantles during core segregation. However, experimental studies show that substantial K can partition into metals that are enriched in sulfur and oxygen. Several models have also suggested that sulfides may have played an important role during episodes of sulfide segregation from a crystallizing magma ocean (sulfide matte) or accretion of S-rich planetary embryos. For Mercury, a sulfide layer could be present between core and mantle, due to immiscibility between Si-rich and S-rich metals. Therefore, here we investigate whether alkali elements (Na, Cs and Rb) could be partly sequestered in planetary cores during their differentiation. We conducted experiments at high pressure and temperature (1 to 5 GPa and up to 1900 °C) to determine partition coefficients of Na, Rb and Cs between metal and silicate. Our results show that pressure, temperature, sulfur and oxygen in metals enhance the partitioning of Na, Rb and Cs into metals, as previously found for K. For all three investigated alkalis (Na, Rb and Cs), we found a maximum partition coefficient of 1 between sulfides containing 13 wt% O and silicate melt. Therefore, S-rich cores or sulfide layers formed due to immiscibility in Fe-S-O systems could have acted as important geochemical reservoirs for alkali elements. Using our experimental data and different assumptions on initial bulk abundances, we evaluate volatile depletion in terrestrial planets, by comparing resulting mantle alkali concentrations after core segregation, with actual concentrations in the Earth's mantle.

  9. Production of volatiles by the red seaweed Gelidium arbuscula (Rhodophyta): emission of ethylene and dimethyl sulfide.

    Science.gov (United States)

    Garcia-Jimenez, Pilar; Brito-Romano, Olegario; Robaina, Rafael R

    2013-08-01

    The effects of different light conditions and exogenous ethylene on the emission of volatile compounds from the alga Gelidium arbuscula Bory de Saint-Vincent were studied. Special emphasis was placed on the possibility that the emission of ethylene and dimethyl sulfide (DMS) are related through the action of dimethylsulfoniopropionate (DMSP) lyase. The conversion of DMSP to DMS and acrylate, which is catalyzed by DMSP lyase, can indirectly support the synthesis of ethylene through the transformation of acrylate to ethylene. After mimicking the desiccation of G. arbuscula thalli experienced during low tides, the volatile compounds emitted were trapped in the headspace of 2 mL glass vials for 1 h. Two methods based on gas chromatography/mass spectrometry revealed that the range of organic volatile compounds released was affected by abiotic factors, such as the availability and spectral quality of light, salinity, and exogenous ethylene. Amines and methyl alkyl compounds were produced after exposure to white light and darkness but not after exposure to exogenous ethylene or red light. Volatiles potentially associated with the oxidation of fatty acids, such as alkenes and low-molecular-weight oxygenated compounds, accumu-lated after exposure to exogenous ethylene and red light. Ethylene was produced in all treatments, especially after exposure to exogenous ethylene. Levels of DMS, the most abundant sulfur-compound that was emitted in all of the conditions tested, did not increase after incubation with ethylene. Thus, although DMSP lyase is active in G. arbuscula, it is unlikely to contribute to ethylene synthesis. The generation of ethylene and DMS do not appear to be coordinated in G. arbuscula. © 2013 Phycological Society of America.

  10. Partitioning of U, Th and K Between Metal, Sulfide and Silicate, Insights into the Volatile-Content of Mercury

    Science.gov (United States)

    Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.; Chidester, B.

    2016-01-01

    During the early stages of the Solar System formation, especially during the T-Tauri phase, the Sun emitted strong solar winds, which are thought to have expelled a portion of the volatile elements from the inner solar system. It is therefore usually believed that the volatile depletion of a planet is correlated with its proximity to the Sun. This trend was supported by the K/Th and K/U ratios of Venus, the Earth, and Mars. Prior to the MESSENGER mission, it was expected that Mercury is the most volatile-depleted planet. However, the Gamma Ray Spectrometer of MESSENGER spacecraft revealed elevated K/U and K/Th ratios for the surface of Mercury, much higher than previous expectations. It is possible that the K/Th and K/U ratios on the surface are not a reliable gauge of the bulk volatile content of Mercury. Mercury is enriched in sulfur and is the most reduced of the terrestrial planets, with oxygen fugacity (fO2) between IW-6.3 and IW-2.6 log units. At these particular compositions, U, Th and K behave differently and can become more siderophile or chalcophile. If significant amounts of U and Th are sequestered in the core, the apparent K/U and K/Th ratios measured on the surface may not represent the volatile budget of the whole planet. An accurate determination of the partitioning of these elements between silicate, metal, and sulfide phases under Mercurian conditions is therefore essential to better constrain Mercury's volatile content and assess planetary formation models.

  11. O papel dos sulfetos volatilizados por acidificação no controle do potencial de biodisponibilidade de metais em sedimentos contaminados de um estuário tropical, no sudeste do Brasil The role of acid volatile sulfide in the control of potential metal bioavailability in contaminated sediments from a tropical estuary, southeast Brazil

    Directory of Open Access Journals (Sweden)

    Érico Casare Nizoli

    2009-01-01

    Full Text Available Measurements of acid volatile sulfide (AVS and simultaneously extracted metals (SEM were combined in order to verify the ecological hazard of contaminated sediments from the Santos-Cubatão Estuarine System (SE Brazil, which is located in one of the most industrialized areas in the Latin America. Intertidal sediments from the Morrão River estuary were collected seasonally in short cores. The redox conditions, organic matter contents and grain-size were the main controlling factors on SEM distribution. However, clear relationships among these variables and AVS were not observed. The molar SEM/AVS ratios were frequently > 1 especially in the summer, suggesting major metal bioavailability hazard in this humid hot season.

  12. Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects

    NARCIS (Netherlands)

    Griethuysen, van C.

    2006-01-01

    This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of

  13. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses

    NARCIS (Netherlands)

    Lange, de H.J.; Griethuysen, van C.; Koelmans, A.A.

    2008-01-01

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the

  14. Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake

    Science.gov (United States)

    Oduro, Harry; Kamyshny, Alexey; Zerkle, Aubrey L.; Li, Yue; Farquhar, James

    2013-11-01

    We have quantified the major forms of volatile organic sulfur compounds (VOSCs) distributed in the water column of stratified freshwater Fayetteville Green Lake (FGL), to evaluate the biogeochemical pathways involved in their production. The lake's anoxic deep waters contain high concentrations of sulfate (12-16 mmol L-1) and sulfide (0.12 μmol L-1 to 1.5 mmol L-1) with relatively low VOSC concentrations, ranging from 0.1 nmol L-1 to 2.8 μmol L-1. Sulfur isotope measurements of combined volatile organic sulfur compounds demonstrate that VOSC species are formed primarily from reduced sulfur (H2S/HS-) and zero-valent sulfur (ZVS), with little input from sulfate. Thedata support a role of a combination of biological and abiotic processes in formation of carbon-sulfur bonds between reactive sulfur species and methyl groups of lignin components. These processes are responsible for very fast turnover of VOSC species, maintaining their low levels in FGL. No dimethylsulfoniopropionate (DMSP) was detected by Electrospray Ionization Mass Spectrometry (ESI-MS) in the lake water column or in planktonic extracts. These observations indicate a pathway distinct from oceanic and coastal marine environments, where dimethylsulfide (DMS) and other VOSC species are principally produced via the breakdown of DMSP by plankton species.

  15. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses.

    Science.gov (United States)

    De Lange, H J; Van Griethuysen, C; Koelmans, A A

    2008-01-01

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics.

  16. Assessment of sediment quality based on acid-volatile sulfide and simultaneously extracted metals in heavily industrialized area of Asaluyeh, Persian Gulf: concentrations, spatial distributions, and sediment bioavailability/toxicity.

    Science.gov (United States)

    Arfaeinia, Hossein; Nabipour, Iraj; Ostovar, Afshin; Asadgol, Zahra; Abuee, Ehsan; Keshtkar, Mozhgan; Dobaradaran, Sina

    2016-05-01

    Sediment samples from the coastal area of Asaluyeh harbor were collected during autumn and spring 2015. The acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) were measured to assess the sediment quality and potential ecological risks. The average concentrations (and relative standard deviation (RSD)) of AVS in the industrial sediments were 12.32 μmol/g (36.91) and 6.34 μmol/g (80.05) in autumn and spring, respectively, while in the urban area, these values were 0.44 μmol/g (123.50) and 0.31 μmol/g (160.0) in autumn and spring, respectively. The average concentrations of SEM (and RSD) in the industrial sediments were 15.02 μmol/g (14.38) and 12.34 μmol/g (20.65) in autumn and spring, respectively, while in the urban area, these values were 1.10 μmol/g (43.03) and 1.06 μmol/g (55.59) in autumn and spring, respectively. Zn was the predominant component (34.25-86.24 %) of SEM, while the corresponding value for Cd, much more toxic ingredient, was less than 1 %. Some of the coastal sediments in the harbor of Asaluyeh (20 and 47 % in autumn and spring, respectively) had expected adverse biological effects based on the suggested criterion by United States Environmental Protection Agency (USEPA), while most stations (80 and 53 % in autumn and spring, respectively) had uncertain adverse effects.

  17. [AVS concentrations in Xinan Creek and the influencing factors].

    Science.gov (United States)

    Liu, Xiao-Bing; Wen, Yan-Mao; Li, Feng; Wu, Chang-Hua; Duan, Zhi-Peng

    2012-07-01

    Sediment and overlying water samples were collected at 10 sampling stations at Xinan Creek, a tidal river in Pearl River Delta, and analyzed for physical and chemical characteristics as well as microbial incicators, in order to reveal the main factors dominating the spatial distribution of acid volatile sulfide (AVS). The effects of Eh, SRB OC and TS on the spatial distribution of AVS were investigated and the impact of AVS on the toxicity of heavy metals in the studied area was evaluated. The results showed that the range of AVS was 0.207-41.453 micromol x g(-1), with an average of 6.684 micromol x g(-1), which is relatively high compared to the results in other studies. The AVS value of the surface layer was higher than the bottom layer in 5 stations. The AVS values in both the surface layer and the bottom layer were highly variable, the coefficients of variation being 93.61% and 153.09% , respectively. The analytical results revealed that TS was the factor with the greatest impact on the spatial distribution of AVS, and the order was TS > OC > Eh > SRB. Potential ecological risk of heavy metals existed in 60% of the smpling stations based on the value of Sigma (SEM5-AVS), however, with the criterion of [Sigma(SEM5-AVS)]/foc, none of them had inacceptable ecological risk. Furthermore, in terms of single species of heavy metals, there was certain risk of toxic effect for all the five heavy metals (Cd, Ni, Cu, Zn and Pb). The above mentioned results will provide valuable data for the in-depth study of the formation mechanism of AVS and helpful reference for environmental impact assessment and scientific rehabilitation of heavy metals in polluted rivers.

  18. Mineralogical studies of sulfide samples and volatile concentrations of basalt glasses from the southern Juan de Fuca Ridge.

    Science.gov (United States)

    Brett, R.; Evans, H.T.; Gibson, E.K.; Hedenquist, J.W.; Wandless, M.-V.; Sommer, M.A.

    1987-01-01

    Specifically considers unusual minerals and geothermometric relations not previously covered. Equilibrium, if attained at all, during deposition of most sulfides was a transient event over a few tens of micrometers at most and was perturbed by rapid temperature and compositional changes of the circulating fluid. Two new minerals were found: one, a hydrated Zn, Fe hydroxy-chlorosulfate, and the other, a (Mn, Mg, Fe) hydroxide or hydroxy-hydrate. Both were formed at relatively low temperatures. Lizardite, starkeyite, and anatase were found for the first time in such an environment.-from Authors

  19. Volatility

    Directory of Open Access Journals (Sweden)

    María Sánchez

    2016-11-01

    Full Text Available The action consists of moving with small kicks a tin of cola refresh -without Brand-from a point of the city up to other one. During the path I avoid bollards, the slope differences between sidewalks, pedestrians, parked motorcycles, etc. Volatility wants to say exactly that the money is getting lost. That the money is losing by gentlemen and by ladies who are neither financial sharks, nor big businessmen… or similarly, but ingenuous people, as you or as me, who walk down the street.

  20. Metal-Silicate-Sulfide Partitioning of U, Th, and K: Implications for the Budget of Volatile Elements in Mercury

    Science.gov (United States)

    Habermann, M.; Boujibar, A.; Righter, K.; Danielson, L.; Rapp, J.; Righter, M.; Pando, K.; Ross, D. K.; Andreasen, R.

    2016-01-01

    During formation of the solar system, the Sun produced strong solar winds, which stripped away a portion of the volatile elements from the forming planets. Hence, it was expected that planets closest to the sun, such as Mercury, are more depleted in volatile elements in comparison to other terrestrial planets. However, the MESSENGER mission detected higher than expected K/U and K/Th ratios on Mercury's surface, indicating a volatile content between that of Mars and Earth. Our experiments aim to resolve this discrepancy by experimentally determining the partition coefficients (D(sup met/sil)) of K, U, and Th between metal and silicate at varying pressure (1 to 5 GPa), temperature (1500 to 1900 C), oxygen fugacity (IW-2.5 to IW-6.5) and sulfur-content in the metal (0 to 33 wt%). Our data show that U, Th, and K become more siderophile with decreasing fO2 and increasing sulfur-content, with a stronger effect for U and Th in comparison to K. Using these results, the concentrations of U, Th, and K in the bulk planet were calculated for different scenarios, where the planet equilibrated at a fO2 between IW-4 and IW-7, assuming the existence of a FeS layer, between the core and mantle, with variable thickness. These models show that significant amounts of U and Th are partitioned into Mercury's core. The elevated superficial K/U and K/Th values are therefore only a consequence of the sequestration of U and Th into the core, not evidence of the overall volatile content of Mercury.

  1. Differences in SEM-AVS and ERM-ERL predictions of sediment impacts from metals in two US Virgin Islands marinas.

    Science.gov (United States)

    Hinkey, Lynne M; Zaidi, Baqar R

    2007-02-01

    Two US Virgin Islands marinas were examined for potential metal impacts by comparing sediment chemistry data with two sediment quality guideline (SQG) values: the ratio of simultaneously extractable metals to acid volatile sulfides (SEM-AVS), and effects range-low and -mean (ERL-ERM) values. ERL-ERMs predicted the marina/boatyard complex (IBY: 2118 microg/g dry weight total metals, two exceeded ERMs) would have greater impacts than the marina with no boatyard (CBM: 231 microg/g dry weight total metals, no ERMs exceeded). The AVS-SEM method predicted IBY would have fewer effects due to high AVS-forming metal sulfide complexes, reducing trace metal bioavailability. These contradictory predictions demonstrate the importance of validating the results of either of these methods with other toxicity measures before making any management or regulatory decisions regarding boating and marina impacts. This is especially important in non-temperate areas where sediment quality guidelines have not been validated.

  2. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses

    Energy Technology Data Exchange (ETDEWEB)

    Lange, H.J. de [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands); Centre for Ecosystem Studies, Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen (Netherlands)], E-mail: marieke.delange@wur.nl; Griethuysen, C. van; Koelmans, A.A. [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands)

    2008-01-15

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics. - Change in AVS is a good proxy for sediment disturbance and combined with SEM it can be used as a suitable predictor for biotic effects of sediment contamination.

  3. Seasonal AVS-SEM relationship in sediments and potential bioavailability of metals in industrialized estuary, southeastern Brazil.

    Science.gov (United States)

    Nizoli, Erico Casare; Luiz-Silva, Wanilson

    2012-04-01

    In anoxic sediments, as those found in estuaries, the mobility of metals can be controlled by the formation of stable sulfide complexes. The potential bioavailability of a metal can then be predicted on the basis of the acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) criterion. Distributions of AVS and SEM (Hg, Cu, Pb, Cd, Zn, and Ni) along the sediment profiles were determined seasonally for three rivers that constitute the Santos-Cubatão estuarine system (SE Brazil), which is located in one of the most industrialized areas of Latin America. AVS and SEM concentrations varied significantly, from 0.04 to 31.9 μmol g(-1) and 0.086-6.659 μmol g(-1), respectively. The highest AVS levels in sediments were detected in the winter, whereas high SEM values predominated in the summer. Considering SEM-AVS molar differences as a parameter to evaluate potential bioavailability, sediments nearest to the industrial area represent higher risk to biota, especially during the summer. It is due to relatively low AVS values and not necessarily high concentrations of metals.

  4. Selenium Sulfide

    Science.gov (United States)

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

  5. Reaction between Hydrogen Sulfide and Limestone Calcines

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Trnka, Otakar; Čermák, Jiří

    2002-01-01

    Roč. 41, č. 10 (2002), s. 2392-2398 ISSN 0888-5885 R&D Projects: GA AV ČR IAA4072711; GA AV ČR IAA4072801 Keywords : hydrogen sulfide * limestone calcines * desulfurization Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

  6. Dust collected in air filters - Possible source of volatile organic compounds and particles; Ger smutsiga luftfilter foersaemrad tilluft ? En studie av emissioner med ursprung i filter

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, J.H.P.; Rosell, Lars

    1998-06-01

    Emissions from dust collected in air filters have been investigated using in situ measurements. Two air filters of different classes (F6 and F8/9) have been exposed to outdoor air for a preconditioning period of six months. After this period measurements have been carried out using two operating conditions, continuous and intermittent. Air samples were taken both up- and downstream of the filters. The air samples were analysed regarding volatile organic compounds (VOCs), including formaldehyde and microbial VOCs (mVOC) and the samples of airborne dust were examined regarding the contents of colony forming units, ergosterol (marker of fungi), and endotoxin (marker of gram negative bacteria). Furthermore, a visual inspection of the airborne dust was conducted using SEM. Particles released when the fan was turned on and a short period after, were monitored using an optical particle counter, slitsamplers (fungus spores) and membrane filters for SEM analysis. After finishing the in situ measurements, the filters were placed in climate chambers for emission sampling. Finally, samples were cut out for analysis of microbial contents in the filter material, both on the dusty and `clean` side of the filters. No consistent change of VOC, aldehyde or mVOC concentrations across the filters could be measured. A significant ozone reduction was seen in one of the in situ measurements. The chamber experiments showed that the filters were a source of various VOCs, e.g. aldehydes and mVOCs. The emission of mVOCs in the chambers was significantly higher for the F8/9 filter, probably due to more and finer dust in that filter. Only a few colonization units (fungi) penetrate filters when running continuously but an increase was noted at the moment the fans were started. The same phenomenon was observed with the optical particle counter, but both the intensity and length of the increase, for colonization units and other particles, were moderate. Mycological examination of the filter

  7. Evaluating the Effects of Metals on Microorganisms in Flooded Paddy Soils Using the SEM/AVS-Based Approach and Measurements of Exchangeable Metal Concentrations.

    Science.gov (United States)

    Kunito, Takashi; Toya, Hitomi; Sumi, Hirotaka; Ishikawa, Yuichi; Toda, Hideshige; Nagaoka, Kazunari; Saeki, Kazutoshi; Aikawa, Yoshio; Matsumoto, Satoshi

    2017-04-01

    We examined possible adverse effects of heavy metals on microbial activity, biomass, and community composition using the simultaneously extracted metals (SEM)/acid-volatile sulfide (AVS)-based approach and measurements of exchangeable metal concentrations in three paddy soils (wastewater-contaminated soil, mine-contaminated soil, and noncontaminated soil) incubated for 60 days under flooded conditions. Incubation under flooding increased pH and decreased Eh in all samples. AVS increased when Eh decreased to approximately -200 mV for the mine-contaminated and noncontaminated soils, while the wastewater-contaminated soil originally had a high concentration of AVS despite its air-dried condition. Addition of rice straw or alkaline material containing calcium carbonate and gypsum increased AVS levels under flooded conditions. We observed no apparent relationship between soil enzyme activity (β-D-glucosidase and acid phosphatase) and concentrations of SEM, [∑SEM - AVS], and exchangeable metals. Bacterial and fungal community composition, assessed using polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) analysis targeting rRNA genes, was largely influenced by site of collection and incubation time, but metal contamination did not influence community composition. We observed significant negative correlations between biomass C and [∑SEM - AVS] and between biomass C and ∑SEM, suggesting that [∑SEM - AVS] and ∑SEM might reflect the bioavailability of organic matter to microorganisms in these soils.

  8. Identification of a potential toxic hot spot associated with AVS spatial and seasonal variation.

    Science.gov (United States)

    Campana, O; Rodríguez, A; Blasco, J

    2009-04-01

    In risk assessment of aquatic sediments, much attention is paid to the difference between acid-volatile sulfide (AVS) and simultaneously extracted metals (SEMs) as indicators of metal availability. Ten representative sampling sites were selected along the estuary of the Guadalete River. Surficial sediments were sampled in winter and summer to better understand SEM and AVS spatial and seasonal distributions and to establish priority risk areas. Total SEM concentration (SigmaSEM) ranged from 0.3 to 4.7 micromol g(-1). It was not significantly different between seasons, however, it showed a significant difference between sampling stations. AVS concentrations were much more variable, showing significant spatial and temporal variations. The values ranged from 0.8 to 22.4 micromol g(-1). The SEM/AVS ratio was found to be <1 at all except one station located near the mouth of the estuary. The results provided information on a potential pollution source near the mouth of the estuary, probably associated with vessel-related activities carried out in a local harbor area located near the station.

  9. Actinobacillus pleuropneumoniae is impaired by the garlic volatile allyl methyl sulfide (AMS) in vitro and in-feed garlic alleviates pleuropneumonia in a pig model

    NARCIS (Netherlands)

    Becker, P.M.; Wikselaar, van P.G.; Mul, M.F.; Pol, A.; Engel, B.; Wijdenes, J.W.; Peet-Schwering, van der C.M.C.; Wisseling, H.J.; Stockhofe-Zurwieden, N.

    2012-01-01

    Decomposition products of ingested garlic are to a certain extent excreted via the lungs. If the supposed health-supporting capacities associated with garlic extend to these exhaled sulfurous compounds, they could have an effect on the course of pneumonia. In this study, the garlic-derived volatile

  10. Combined SEM/AVS and attenuation of concentration models for the assessment of bioavailability and mobility of metals in sediments of Sepetiba Bay (SE Brazil).

    Science.gov (United States)

    Ribeiro, Andreza Portella; Figueiredo, Ana Maria Graciano; dos Santos, José Osman; Dantas, Elizabeth; Cotrim, Marycel Elena Barboza; Figueira, Rubens Cesar Lopes; Silva Filho, Emmanoel V; Wasserman, Julio Cesar

    2013-03-15

    This study proposes a new methodology to study contamination, bioavailability and mobility of metals (Cd, Cu, Ni, Pb, and Zn) using chemical and geostatistics approaches in marine sediments of Sepetiba Bay (SE Brazil). The chemical model of SEM (simultaneously extracted metals)/AVS (acid volatile sulfides) ratio uses a technique of cold acid extraction of metals to evaluate their bioavailability, and the geostatistical model of attenuation of concentrations estimates the mobility of metals. By coupling the two it was observed that Sepetiba Port, the urban area of Sepetiba and the riverine discharges may constitute potential sources of metals to Sepetiba Bay. The metals are concentrated in the NE area of the bay, where they tend to have their lowest mobility, as shown by the attenuation model, and are not bioavailable, as they tend to associate with sulfide and organic matter originated in the mangrove forests of nearby Guaratiba area. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Support Effect in Hydrodesulfurization over Ruthenium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    2009-01-01

    Roč. 51, č. 2 (2009), s. 146-149 ISSN 1337-7027 R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support effect Subject RIV: CC - Organic Chemistry

  12. Assessment of heavy metals pollution using AVS-SEM and fractionation techniques in Edku Lagoon sediments, Mediterranean Sea, Egypt.

    Science.gov (United States)

    El Zokm, Gehan M; Okbah, Mohamed A; Younis, Alaa M

    2015-01-01

    A method is presented to evaluate the fractionation of metals (Fe, Zn, Cu, Pb, Cd and Ni), acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in Edku lagoon sediments. Thirteen sediment samples were collected from the study area in the period of 2010-2011 to assess the potential bioavailability and toxicity of the selected metals. According to classification of the Interim Sediment Quality Quidelines (ISQG), five stations near the drains exhibited 10% toxic probability. The high AVS and low ∑SEM ranges in Summer were identified as 6-138 and 0.86-3.3 µmol g(-1) dry wet, respectively which are referring to the low mobility of heavy metals in this season and vice versa for winter (2.5-23.9 and 1.16-3.82 µmol g(-1) dry wet, respectively). According to the evaluation of USEPA, all sediment samples showed ∑SEM/AVS heavy metals in Edku lagoon sediments posed a low risk of adverse biological effects due to cadmium, copper, lead, nickel and zinc in all evaluated stations.

  13. Coastal surface sediment quality assessment in Leizhou Peninsula (South China Sea) based on SEM-AVS analysis.

    Science.gov (United States)

    Li, Feng; Lin, Jin-qin; Liang, Yan-yan; Gan, Hua-yang; Zeng, Xiang-yun; Duan, Zhi-peng; Liang, Kai; Liu, Xing; Huo, Zhen-hai; Wu, Chang-hua

    2014-07-15

    Surface sediments from the coastal area of the Leizhou Peninsula in the South China Sea were collected and analyzed and the potential ecological risks in the area were assessed based on acid-volatile sulfide (AVS) model. The AVS levels are between 0.109 and 55.6 μmol g(-1), with the average at 4.45 μmol g(-1). The high AVS-concentration zones include the aquaculture areas of Liusha Bay and the densely populated areas of Zhanjiang Bay. The simultaneously extracted metals (SEM) range from 0.026 μmol g(-1) to 8.61 μmol g(-1), with the average at 0.843 μmol g(-1). Most of high SEM-concentration stations were located in ports or aquaculture zones. Most of the coastal surface sediments of the Leizhou Peninsula (90%) had no adverse biological effects according to the criterion proposed by USEPA (2005); while adverse effects were uncertain in some stations (8%); even in 2 stations (2%) adverse biological effects may be expected. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. AUTOMATION AV GALLERKLIPPARE

    OpenAIRE

    Taboada Vargas, Marco Antonio

    2016-01-01

    Detta examensarbete handlar om automatisering och assistans att CE-märka en maskin. Arbetet innefattade automationsplanering, tillverkning av elskåp, montering på maskin och igångkörning. Automationsplaneringen bestod av elritningar och programmering. Elsystemet bestod av elskåp med bl.a. programmerbar logik, touch-panel och säkerhetskomponenter. CE-märkning utfördes enligt de direktiv, standarder och säkerhetsföreskrifter som bör följas. Nu med det nya automatiserade systemet är samm...

  15. The risk assessment of heavy metals in Futian mangrove forest sediment in Shenzhen Bay (South China) based on SEM-AVS analysis.

    Science.gov (United States)

    Chai, Minwei; Shen, Xiaoxue; Li, Ruili; Qiu, Guoyu

    2015-08-15

    The risks of heavy metal in Futian mangrove forest sediment were assessed using the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) methods. The results indicated that AVS distributions were more variable than the SEM distributions at all 16 sampling sites. The positive correlation between AVS and SEM indicated that their similar formative and existing conditions and that AVS acted as an important carrier for SEM. The major SEM component was Zn (69.7.3-94.2%), whereas the Cd contribution (the most toxic metal present) to SEM was no more than 1%. The possible adverse effects caused by heavy metals at ten sampling sites may be due to higher levels of SEMs, rather than AVSs. The total organic carbon (TOC) was an important metal-binding phase in the sediments. Taking into account the TOC concentration, there were no adverse effects due to heavy metals in any of the Futian mangrove forest sediments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Importance of sulfide interaction with iron as regulator of the microbial community in biogas reactors and its effect on methanogenesis, volatile fatty acids turnover, and syntrophic long-chain fatty acids degradation.

    Science.gov (United States)

    Shakeri Yekta, Sepehr; Ziels, Ryan M; Björn, Annika; Skyllberg, Ulf; Ejlertsson, Jörgen; Karlsson, Anna; Svedlund, Matilda; Willén, Magnus; Svensson, Bo H

    2017-05-01

    The inhibitory effects of sulfide on microbial processes during anaerobic digestion have been widely addressed. However, other effects of sulfide are less explored, given that sulfide is a potential sulfur source for microorganisms and its high reactivity triggers a suit of abiotic reactions. We demonstrated that sulfide interaction with Fe regulates the dynamics and activities of microbial community during anaerobic digestion. This was manifested by the S:Fe molar ratio, whose increase adversely influenced the acetoclastic methanogens, Methanosaeta, and turnover of acetate. Dynamics of hydrogenotrophic methanogens, Methanoculleus and Methanobrevibacter, were presumably influenced by sulfide-induced changes in the partial pressure of hydrogen. Interestingly, conversion of the long-chain fatty acid (LCFA), oleate, to methane was enhanced together with the abundance of LCFA-degrading, β-oxidizing Syntrophomonas at an elevated S:Fe molar ratio. The results suggested that sulfur chemical speciation is a controlling factor for microbial community functions in anaerobic digestion processes. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. Skyggedom av enkepensjonsdommen

    DEFF Research Database (Denmark)

    Rognlien, Ida Gundersby

    2014-01-01

    Masteroppgaven undersøker om bortfall av ektefellepensjon ved lovendring med tilbakevirkende kraft er i strid med retten til eiendom etter EMK TP 1 art 1. Skyggedommetoden/ Feminist Judgments -metoden brukes for å gjenskrive enkepensjonsdommen Rt.2006.262 i et feministisk perspektiv. Da mannen døde.......1975.220. I spørsmålet om inngrepet er proporsjonalt ble vektlagt at det ikke foreligger en transparent avveining av de relevante interessene. Videre er hensynene bak og behovene for den opprinnelige ektefellepensjonen fortsatt tilstede, og de er ikke tilstrekkelig avveid mot formålene med inngrepet...

  18. Forenkling av tekniske systemer

    DEFF Research Database (Denmark)

    Førland-Larsen, Arne; Bramslev, Katharina; Halderaker, Ingrid

    De fleste moderne kontorbygg har omfattende tekniske installasjoner. Mange byggeiere opplever at dagens kompliserte tekniske anlegg ikke fungerer som de skal. De ender med å få reklamasjoner, høyt energiforbruk og klager på inneklima. Kan en kraftig forenkling av ventilasjons-, oppvarmings- og...

  19. SULFIDE MINERALS IN SEDIMENTS

    Science.gov (United States)

    The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

  20. En av gutta

    DEFF Research Database (Denmark)

    Neumann, Cecilie Basberg; Rysst, Mari; Bjerck, Mari

    2012-01-01

    Hvilken betydning har kjønn og klær for kvinner som arbeider i mannsdominerte arbeiderklasseyrker? Forfatterne av denne artikkelen finner at kvinnene må nedtone sitt kjønn og sin seksualitet gjennom å dekke til kroppen, i klær laget for menn, for å signalisere at de er på jobb for å arbeide. Hvor...

  1. Summer Student Report - AV Workflow

    CERN Document Server

    Abramson, Jessie

    2014-01-01

    The AV Workflow is web application which allows cern users to publish, update and delete videos from cds. During my summer internship I implemented the backend of the new version of the AV Worklow in python using the django framework.

  2. Iridium Sulfide and Ir Promoted Mo Based Catalysts.

    Czech Academy of Sciences Publication Activity Database

    Vít, Zdeněk

    2007-01-01

    Roč. 322, - (2007), s. 142-151 ISSN 0926-860X R&D Projects: GA ČR(CZ) GA104/06/0870 Institutional research plan: CEZ:AV0Z40720504 Keywords : iridium sulfide * IrMo catalyst * hydrodesulfurization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2007

  3. Validering av Evolution 220

    OpenAIRE

    Krakeli, Tor-Arne

    2013-01-01

    - Det har blitt kjøpt inn et nytt spektrofotometer (Evolution 220, Thermo Scientific) til BioLab Nofima. I den forbindelsen har det blitt utført en validering som involverer kalibreringsstandarder fra produsenten og en test på normal distribusjon (t-test) på to metoder (Total fosfor, Tryptofan). Denne valideringen fant Evolution 220 til å være et akseptabelt alternativ til det allerede benyttede spektrofotometeret (Helios Beta). På bakgrunn av noen instrumentbegrensninger må de aktuelle an...

  4. Antifoaming materials in G.S. (Girlder sulfide) heavy water plants. Thermical stability. Pt. 2

    International Nuclear Information System (INIS)

    Delfino, C.A.

    1986-01-01

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). About twenty commercial surfactants were studied from the point of view of their thermical stability. (Author) [es

  5. Ultralydfremstilling av fostervekst

    Directory of Open Access Journals (Sweden)

    Synnøve Lian Johnsen

    2009-09-01

    Full Text Available Ultralyd billeddanning er i dag den beste undersøkelsesmetoden vi har til å overvåke fosterets utvikling og vekst. Ultralydmåling av fosterets størrelse og biometriske referansetabeller for svangerskapet brukes til å fastsette svangerskapets alder, beregne termin og vurdere fosterets vekst. Optimal studiedesign er ulik for hvert av disse formålene. Det er stor variasjon i fysiologisk vekst og en utfordring å identifisere fostre som har dårlig tilvekst. En enkeltmåling av fosteret kan fortelle oss om det er lite eller stort i forhold til andre fostre, men ikke om størrelsen er passelig i forhold til forventet fysiologisk vekst for dette fosteret. Tilpassede referansemodeller ("customised" justerer forventet størrelse i relasjon til føtale og maternelle faktorer og har vist seg å bedre identifisere sanne veksthemmede fostre enn bare å klassifisere i henhold til 2,5, 5 eller 10 persentilen. Men et foster som i utgangspunktet er stort for alderen, men etter hvert vokser langsomt vil ikke nødvendigvis bli fanget opp ved en slik enkeltmåling. Serielle målinger vil hjelpe, men en slik longitudinell metode blir ikke fullt ut utnyttet før det appliseres betinget ("conditional" vekstberegning. Betingelsesleddene for variasjon i vekst og målemetode kalkuleres ut fra longitudinelle data og kan så anvendes for det enkelte foster. En første måling brukes til å beregne forventet vekst og variasjon for en neste måling. Denne metoden forventes å skjerpe diagnostikken for vekst-avvik i alle vektklasser og kan sammen med tilpasningen av andre faktorer bedre overvåkningen av risikosvangerskapUltrasonographic imaging is today the best method for assessing fetal size and monitoring fetal growth. Ultrasound measurements of fetal size are used for age, size and growth assessment, but the statistical design and analysis are different for each of these purposes. Physiological ranges for fetal growth are wide and the identification of fetal

  6. Purification of hydrogen sulfide

    International Nuclear Information System (INIS)

    Tsao, U.

    1978-01-01

    A process is described for purifying a hydrogen sulfide gas stream containing carbon dioxide, comprising (a) passing the gas stream through a bed of solid hydrated lime to form calcium hydrosulfide and calcium carbonate and (b) regenerating hydrogen sulfide from said calcium hydrosulfide by reacting the calcium hydrosulfide with additional carbon dioxide. The process is especially applicable for use in a heavy water recovery process wherein deuterium is concentrated from a feed water containing carbon dioxide by absorption and stripping using hydrogen sulfide as a circulating medium, and the hydrogen sulfide absorbs a small quantity of carbon dioxide along with deuterium in each circulation

  7. Helseeffekter av byluftpartikler

    Directory of Open Access Journals (Sweden)

    Magne Refsnes

    2009-10-01

    Full Text Available Svevestøv i byluft består av forbrenningspartikler og mineralpartikler med svært forskjellige størrelser og kjemiske egenskaper. Svevestøvet kan deles inn i størrelsesfraksjoner som PMAmbient particulate matter (PM comprises particles from different combustion processes and a variety of mineral particles. The particles vary widely in size distribution and chemical/physical characteristics. PM is often divided into size fractions with different aerodynamic diameters: PM10 (PM ! 10 mm, PM2.5 (PM ! 2.5 mm and PM0.1 (PM ! 0.1 mm. Recent population studies have found an association between an increase in mortality and morbidity due to lung and/or cardiovascular disease and short-term increases in PM. The relative risk (RR was approximately 1.005 for an increase in 10 mg/m3 PM10, without an observed threshold even at concentrations below 10 mg/m3. Chronic exposure has been investigated to a lesser extent, but longterm exposure to PM2.5 has been found to be associated with an approximately 10-fold greater increase in RR than short-term exposures. Experimental studies with volunteers in chamber and field studies show mild lung or cardiovascular responses at concentrations of ambient particles (PM2.5/PM10: 100-200 mg/m3 that may occur during episodes of air pollution. Animal studies at higher concentrations have shown stronger responses. The experimental studies support the epidemiological evidence for an adverse health effect of PM. Both population- and experimental studies indicate the existence of vulnerable individuals. At low to average ambient concentrations there seems to exist a discrepancy between the results of population- and experimental studies that might be due to the absence of the most vulnerable individuals in the experimental studies. Together with cell culture experiments, human and animal studies indicate the importance of physical and chemical properties of the particles (size, content of metals, organics, endotoxins, etc. for

  8. Læring av erfaring?

    DEFF Research Database (Denmark)

    Ramvi, Ellen

    Hva skal til for å lære av erfaring? Denne avhandlingen er en empirisk baseret undersøkelse av ungdosmskolelæreres muligheter og betingelser for å "lære av erfaring" i den særlige betydning av begrepet  W. Bion gir i sin psykoanalytiske teori. Undersøgelsen baserer seg på et feltarbeid som strekker...... seg over ett skoleår. Datamaterialet ble samlet inn via observerasjoner og mer eller mindre strukturerte samtaler med lærere ved to forskellige norske ungdsomsskoler. Analysen av materialet foregår i to trinn: først en fenomenologisk analyse, tett på lærernes egne beskrivelser og refleksjoner av...... lærerarbeidet, dets udfordringer og vanskeligheter, og deretter en psykoanalytisk perspektivering av de fenomenologiske analyseresultatene. Analysen viser en almindelig lærerhverdag og en skoleorganisation, hvor lærernes "læring av erfaring" i stor utstrekning blokkeres i et vekselspill mellem lærernes flukt...

  9. Hydrogen sulfide concentration in Beaver Dam Creek

    International Nuclear Information System (INIS)

    Kiser, D.L.

    1979-01-01

    Concentration-time profiles calculated with LODIPS for various hypothetical releases of hydrogen sulfide from the heavy water extraction facility predict lethal conditions for swamp fish from releases as small as 568 kg discharged over a period of 30 minutes or from releases of 1818 kg discharged over a period of 6 hours or less. The necessary volatilization and oxidation coefficients for LODIPS were derived from field measurements following planned releases of H 2 S. Upsets in the operation of the wastewater strippers in the Girdler-Sulfide (GS) heavy water extraction facility in D Area have released significant amounts of dissolved H 2 S to Beaver Dam Creek. Because H 2 S is toxic to fish in concentrations as low as 1 mg/liter, the downstream environmental impact of H 2 S releases from D Area was evaluated

  10. Mödrars upplevelser av att drabbas av postpartumdepression

    OpenAIRE

    Wallin, Rebecca; Pitkämäki, Kia

    2016-01-01

    Bakgrund: Postpartumdepression (PPD) drabbar mellan 8-15% av alla kvinnor som föder barn och innebär stora påfrestningar för både modern, partnern och spädbarnet. Utvecklandet av PPD har multifaktoriella orsaker som tidigare psykiatrisk sjukdom, dåligt parförhållande och brist på socialt stöd. Syfte: Studiens syfte var att undersöka kvinnors upplevelser av postpartumdepression. Metod: Studien är en litteraturöversikt där vetenskapliga artiklar motsvarande studiens syfte granskades. Samtliga a...

  11. Hydrogen sulfide production from cysteine and homocysteine by periodontal and oral bacteria.

    Science.gov (United States)

    Yoshida, Akihiro; Yoshimura, Mamiko; Ohara, Naoya; Yoshimura, Shigeru; Nagashima, Shiori; Takehara, Tadamichi; Nakayama, Koji

    2009-11-01

    Hydrogen sulfide is one of the predominant volatile sulfur compounds (VSCs) produced by oral bacteria. This study developed and evaluated a system for detecting hydrogen sulfide production by oral bacteria. L-methionine-alpha-deamino-gamma-mercaptomethane-lyase (METase) and beta carbon-sulfur (beta C-S) lyase were used to degrade homocysteine and cysteine, respectively, to produce hydrogen sulfide. Enzymatic reactions resulting in hydrogen sulfide production were assayed by reaction with bismuth trichloride, which forms a black precipitate when mixed with hydrogen sulfide. The enzymatic activities of various oral bacteria that result in hydrogen sulfide production and the capacity of bacteria from periodontal sites to form hydrogen sulfide in reaction mixtures containing L-cysteine or DL-homocysteine were assayed. With L-cysteine as the substrate, Streptococcus anginosus FW73 produced the most hydrogen sulfide, whereas Porphyromonas gingivalis American Type Culture Collection (ATCC) 33277 and W83 and Fusobacterium nucleatum ATCC 10953 produced approximately 35% of the amount produced by the P. gingivalis strains. Finally, the hydrogen sulfide found in subgingival plaque was analyzed. Using bismuth trichloride, the hydrogen sulfide produced by oral bacteria was visually detectable as a black precipitate. Hydrogen sulfide production by oral bacteria was easily analyzed using bismuth trichloride. However, further innovation is required for practical use.

  12. Volatility Discovery

    DEFF Research Database (Denmark)

    Dias, Gustavo Fruet; Scherrer, Cristina; Papailias, Fotis

    The price discovery literature investigates how homogenous securities traded on different markets incorporate information into prices. We take this literature one step further and investigate how these markets contribute to stochastic volatility (volatility discovery). We formally show...... that the realized measures from homogenous securities share a fractional stochastic trend, which is a combination of the price and volatility discovery measures. Furthermore, we show that volatility discovery is associated with the way that market participants process information arrival (market sensitivity......). Finally, we compute volatility discovery for 30 actively traded stocks in the U.S. and report that Nyse and Arca dominate Nasdaq....

  13. Mesostructured metal germanium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

    1999-12-29

    A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

  14. Verdsettelse av Bremnes Seashore AS

    OpenAIRE

    Selle, Simon Flatebø

    2017-01-01

    Siden etablering i 1946 har Bremnes Seashore AS ønsket å levere verdens beste lakseprodukt. Det startet i det små med pigghå og regnbueørret før det i 1970 ble satset på det vi i dag kjenner som kommersiell lakseoppdrett. Bremnes beskrives av Innovasjon Norge som bransjerevolusjonær. Spesielt viktig var deres utvikling og implementering av pre-rigor foredling som i dag utgjør standarden for ethvert moderne fiskeslakteri. I nyere tid ønsker de å gjøre det igjen med utvikling av ...

  15. Lokalisering av arbeidsplasser og boliger

    DEFF Research Database (Denmark)

    Næss, Petter

    2011-01-01

    En miljømessig effektiv lokalisering av arbeidsplasser og boliger sikter mot å begrense - og helst redusere - biltrafikk og miljøproblemer knyttet til bytransport, sammenliknet med alternative lokaliseringer. En effektiv transportmessig lokalisering kan også bidra til å redusere tap av verdifulle...... arealer (f eks jordbruksareal eller natur- og friluftsområder) utenfor dagens tettstedsgrense. Tiltaket må samtidig utformes slik at en kan bevare viktige bomiljøkvaliteter og så mye som mulig av de grønne arealene innenfor tettbebyggelsen....

  16. UV Laser Co-Photolytic Approach to Gas-Phase Formation and Deposition of Nano-Sized Germanium Sulfides.

    Czech Academy of Sciences Publication Activity Database

    Tomovska, R.; Vorlíček, Vladimír; Boháček, Jaroslav; Šubrt, Jan; Pola, Josef

    2006-01-01

    Roč. 182, 1 (2006) , s. 107-111 ISSN 0022-3573 R&D Projects: GA MŠk(CZ) ME 486 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z10100523; CEZ:AV0Z40320502 Keywords : laser deposition * germanium sulfides * nanomaterials Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.533, year: 2006

  17. Motorsystem : Roderstyrning av autonom segelrobot

    OpenAIRE

    Frank, Morgan

    2017-01-01

    Examensarbetet har gjorts på begäran av ÅSR (Åland Sailing Robots) genom Anna Friebe. Syftet med arbetet är att skapa energisnålt motorsystem för styrning av vindflöjeln och roder till 4 meter lång segelrobot som ägs av ÅSR. Ett exemplar av den styranordningen som jag anser kommer att fungera bäst för en robotsegelbåt har konstruerats och kopplats upp på testbänk där jag sedan har lämnat över arbetet för programmering. I detta arbete har jag undersökt motorer, givare, motorstyrni...

  18. Effektivisering av arbetet med rumsbeskrivningar

    OpenAIRE

    Enström, Magnus

    2016-01-01

    För att ta byggbranschen till nästa steg i utvecklingen är BIM det naturliga steget. Iteorin tycks många av lösningarna som medföljer implementationen av BIM varaenkla att förstå och skapa, i praktiken ligger dock de tekniska lösningarna långt ifrånen full implementation i branschen. I arbetet med olika typer av beskrivningar inomett byggprojekt har utvecklingen med hjälp av BIM stått still länge. Då det inte finnsnågot vedertaget sätt att utnyttja en BIM-modells information för att fylla oli...

  19. Studies on silicone based antifoaming agents to be used in G.S. (Girlder sulfide) heavy water plants

    International Nuclear Information System (INIS)

    Delfino, C.A.

    1986-01-01

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2MPa, up to 230 deg C). Six commercial silicone based antifoaming agents were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author) [es

  20. Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical and thermical stability. Pt. 3

    International Nuclear Information System (INIS)

    Delfino, C.A.; Rojo, E.A.

    1988-01-01

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). Five commercial surfactants were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author) [es

  1. Astrometry VLBI in Space (AVS

    Science.gov (United States)

    Altunin, V.; Alekseev, V.; Akim, E.; Eubanks, M.; Kingham, K.; Treuhaft, R.; Sukhanov, K.

    1995-01-01

    A proposed new space radio astronomy mission for astrometry is described. The Astrometry VLBI (very long baseline) in Space (AVS) nominal mission includes two identical spacecraft, each with a 4-m antenna sending data to a 70-m ground station. The goals of AVS are improving astrometry accuracy to the microarcsecond level and improving the accuracy of the transformation between the inertial radio and optical coordinate reference frames.

  2. Astrometry VLBI in Space (AVS)

    Science.gov (United States)

    Cheng, Li-Jen; Reyes, George

    1995-01-01

    This paper describes a proposal for a new space radio astronomy mission for astrometry using Very Long Baseline Interferometry (VLBI) called Astrometry VLBI in Space (AVS). The ultimate goals of AVS are improving the accuracy of radio astrometry measurements to the microarcsecond level in one epoch of measurements and improving the accuracy of the transformation between the inertial radio and optical coordinate reference frames. This study will also assess the impact of this mission on astrophysics astrometry and geophysics.

  3. Virtual volatility

    Science.gov (United States)

    Silva, A. Christian; Prange, Richard E.

    2007-03-01

    We introduce the concept of virtual volatility. This simple but new measure shows how to quantify the uncertainty in the forecast of the drift component of a random walk. The virtual volatility also is a useful tool in understanding the stochastic process for a given portfolio. In particular, and as an example, we were able to identify mean reversion effect in our portfolio. Finally, we briefly discuss the potential practical effect of the virtual volatility on an investor asset allocation strategy.

  4. Effect of Sodium Sulfide on Ni-Containing Carbon Monoxide Dehydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Jian Feng; Paul A. Lindahl

    2004-07-28

    OAK-B135 The structure of the active-site C-cluster in CO dehydrogenase from Carboxythermus hydrogenoformans includes a {mu}{sup 2}-sulfide ion bridged to the Ni and unique Fe, while the same cluster in enzymes from Rhodospirillum rubrum (CODH{sub Rr}) and Moorella thermoacetica (CODH{sub Mt}) lack this ion. This difference was investigated by exploring the effects of sodium sulfide on activity and spectral properties. Sulfide partially inhibited the CO oxidation activity of CODH{sub Rr} and generated a lag prior to steady-state. CODH{sub Mt} was inhibited similarly but without a lag. Adding sulfide to CODH{sub Mt} in the C{sub red1} state caused the g{sub av} = 1.82 EPR signal to decline and new features to appear, including one with g = 1.95, 1.85 and (1.70 or 1.62). Removing sulfide caused the g{sub av} = 1.82 signal to reappear and activity to recover. Sulfide did not affect the g{sub av} = 1.86 signal from the C{sub red2} state. A model was developed in which sulfide binds reversibly to C{sub red1}, inhibiting catalysis. Reducing this adduct causes sulfide to dissociate, C{sub red2} to develop, and activity to recover. Using this model, apparent K{sub I} values are 40 {+-} 10 nM for CODH{sub Rr} and 60 {+-} 30 {micro}M for CODH{sub Mt}. Effects of sulfide are analogous to those of other anions, including the substrate hydroxyl group, suggesting that these ions also bridge the Ni and unique Fe. This proposed arrangement raises the possibility that CO binding labilizes the bridging hydroxyl and increases its nucleophilic tendency towards attacking Ni-bound carbonyl.

  5. Iodine volatility

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  6. Sediment quality assessment in a coastal lagoon (Ravenna, NE Italy) based on SEM-AVS and sequential extraction procedure.

    Science.gov (United States)

    Pignotti, Emanuela; Guerra, Roberta; Covelli, Stefano; Fabbri, Elena; Dinelli, Enrico

    2018-09-01

    Sediments from the Pialassa Piomboni coastal lagoon (NE Italy) were studied to assess the degree of contamination and ecological risk related to trace metals by combining a geochemical characterization of bulk sediments with the assessment of the bioavailable forms of trace metals. With this purpose, sediment contamination (Cd, Cu, Hg, Ni, Pb, and Zn) was assessed by Enrichment Factors (EFs), and potential bioavailability by the Simultaneously Extracted Metals and Acid Volatile Sulfides (SEM-AVS) approach (Cd, Cu, Ni, Pb, and Zn), and by Sequential Extraction Procedure (Co, Cr, Cu, Ni, Pb, and Zn). On average, Cr and Ni exhibited no contamination (EF ≤1.5), and a predominance in the residual fraction of the sediment, indicating natural origin for these metals. Cu, Pb and Zn displayed a local contamination, which resulted in a higher proportion of Cu bound to the reducible and oxidizable fractions (~30% and ~40% as median, respectively), and Pb mostly associated with the reducible phase (~60% as median). Hence, Cu and Pb could be mobilized when environmental conditions become reducing or oxidizing. Zn resulted mainly partitioned into the reducible and residual fractions (~50% as median, in both fractions). The Risk Assessment Code (RAC) indicated that approximately 30% of samples had >10% of total Zn weakly bound to the sediment, suggesting a medium risk of exposure for aquatic organisms. RAC results were consistent with the ∑SEM-AVS findings, pointing to possible adverse effects for aquatic biota in ~30% of samples, with Zn mostly accounting for the total metal bioavailability. Hg showed a moderate to very severe enrichment, indicating that a substantial amount of this metal derives from anthropogenic sources and may pose adverse effects on the aquatic biota of the Pialassa Piomboni lagoon. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. The Effect of gamma-Al2O3, TiO2, and ZrO2 Supports on Hydrodesulfurization Activity of Transition-Metal Sulfides

    Czech Academy of Sciences Publication Activity Database

    Kaluža, Luděk; Zdražil, Miroslav

    2008-01-01

    Roč. 73, 8-9 (2008), s. 945-955 ISSN 0010-0765 R&D Projects: GA ČR GP104/06/P034 Institutional research plan: CEZ:AV0Z40720504 Keywords : hydrodesulfurization * transition metal sulfides * sulfide catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.784, year: 2008

  8. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  9. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen

    2012-01-01

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  10. Klubbhusverksamheten - Betydelse av dagligt arbete

    OpenAIRE

    Niskanen, Karolina

    2011-01-01

    Syftet med undersökningen är att beskriva klubbhusmedlemmarnas uppfattning om det dagliga arbetet och dess betydelse för välmående i vardagen. Undersökningen utfördes i form av kvalitativa intervjuer med fem medlemmar av klubbhuset Pelaren i Mariehamn. Forskningsfrågorna som skulle besvaras var hur klubbhusmedlemmarna uppfattar arbete, vad arbete har för betydelse för deras hälsa, vilka aktiviteter de upplever som betydelsefulla i klubbhusverksamheten samt vad i klubbhusmiljön som stöder dem ...

  11. Simulering av muskelaktivitet vid pedalbromsning

    OpenAIRE

    Ejdepalm, Erik; Westerdahl, Walter

    2009-01-01

    En muskeloskeletal kroppsmodell har undersökts med avseende på maximal muskelbelastning genom biomekanisk simulering i programmet AnyBody. En kroppsmodell har låtits interagera med ett reglage i form av en bromspedal från en Saab 9-3 och muskelbelastningen till följd av att pedalen trampas ned har minimerats. De parametrar hos pedalen som har varierats är initialvinkeln och returfjäderns fjäderkonstant. Den sits på vilken kroppsmodellen sitter har flyttats vertikalt och horisontellt i förhåll...

  12. Titanocene sulfide chemistry

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal

    2016-01-01

    Roč. 314, MAY 2016 (2016), s. 83-102 ISSN 0010-8545 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : titanocene sulfide chemistry * photolysis * titanocene hydrosulfides Ti-(SH)n Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.324, year: 2016

  13. Electron transfer to sulfides:

    International Nuclear Information System (INIS)

    Meneses, Ana Belen; Antonello, Sabrina; Arevalo, Maria Carmen; Maran, Flavio

    2005-01-01

    The problem of characterizing the steps associated with the dissociative reduction of sulfides has been addressed. The electrochemical reduction of diphenylmethyl para-methoxyphenyl sulfide in N,N-dimethylformamide, on both glassy carbon and mercury electrodes, was chosen as a test system. The electrode process involves the slow heterogeneous outer-sphere electron transfer to the sulfide, the fast cleavage of the C-S bond, the reduction of the ensuing carbon radical, and the self-protonation triggered by the generation of the strong base Ph 2 CH - . The latter reaction is rather slow, in agreement with the large intrinsic barriers characterizing proton transfers between CH-acids and carbon bases. The dissociative reduction was studied in the presence of an exogenous acid. The results, obtained by convolution analysis, point to a stepwise DET mechanism in which the ET step is accompanied by rather large reorganization energy. Similar results were obtained on both electrode materials. Analysis of the heterogeneous electron transfer and associated C-S bond cleavage indicate that the reduction of this and other sulfides lies between the stepwise dissociative electron transfers leading to the formation of stiff π* radical anions and those going through the intermediacy of loose σ* radical anions

  14. Unstable volatility

    DEFF Research Database (Denmark)

    Casas, Isabel; Gijbels, Irène

    2012-01-01

    The objective of this paper is to introduce the break-preserving local linear (BPLL) estimator for the estimation of unstable volatility functions for independent and asymptotically independent processes. Breaks in the structure of the conditional mean and/or the volatility functions are common...... in Finance. Nonparametric estimators are well suited for these events due to the flexibility of their functional form and their good asymptotic properties. However, the local polynomial kernel estimators are not consistent at points where the volatility function has a break. The estimator presented...

  15. Bruk av kartleggingsresultater i forbedringsarbeid

    DEFF Research Database (Denmark)

    Nordahl, Thomas; Hansen, Line Skov

    . Barnehagen har gjerne tilgang på informasjon fra kartlegginger, men det er ikke alltid denne informasjonen blir systematisk analysert og aktivt brukt i forbedringsarbeid. Forfatterne viser hvordan slike analyser kan gjennomføres på forskjellige nivåer i den enkelte barnehage, og vektlegger viktigheten av...

  16. Chasing volatility

    DEFF Research Database (Denmark)

    Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo

    The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification, the condi......The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification...... estimate alternative specifications of the model using a set of daily bipower measures for 7 stock indexes and 16 individual NYSE stocks. The estimates of the jump component confirm that the probability of jumps dramatically increases during the financial crisis. Compared to other realized volatility...... models, the introduction of the jump component provides a sensible improvement in the fit, as well as for in-sample and out-of-sample volatility tail forecasts....

  17. Non-stoichiometry in sulfides produced by pulsed laser deposition

    DEFF Research Database (Denmark)

    Canulescu, Stela; Cazzaniga, Andrea Carlo; Ettlinger, Rebecca Bolt

    and the most volatile component in the film. A very well studied case in the one of oxides, for which the O2 or N2O background gases can reduce the loss of oxygen in the growing films. A much less studied case is the one of sulfides or selenides, such as the solar cell absorber layers of CIGS (Cu(Ga,In)Se2...

  18. Hydrogen Sulfide Removal from Air by Acidithiobacillus thiooxidans in a Trickle Bed Reactor

    Czech Academy of Sciences Publication Activity Database

    Ramirez, M.; Gómez, J. M.; Cantero, D.; Páca, J.; Halecký, M.; Kozliak, E. I.; Sobotka, Miroslav

    2009-01-01

    Roč. 54, č. 5 (2009), s. 409-414 ISSN 0015-5632 Institutional research plan: CEZ:AV0Z50200510 Keywords : 2-STAGE BIOTRICKLING FILTER * THIOBACILLUS-THIOPARUS * DIMETHYL SULFIDE Subject RIV: EE - Microbiology, Virology Impact factor: 0.978, year: 2009

  19. Heterogeneous ion-exchange membranes based on sulfonated poly(1,4-phenylene sulfide)

    Czech Academy of Sciences Publication Activity Database

    Schauer, Jan; Kůdela, Vlastimil; Richau, K.; Mohr, R.

    2006-01-01

    Roč. 198, 1-3 (2006), s. 256-264 ISSN 0011-9164 R&D Projects: GA ČR GA203/05/0080 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(1,4-phenylene sulfide) sulfonated * ion-exchange membrane Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.917, year: 2006

  20. Thermal analysis of sulfide Ge-Ga glasses doped by praseodymium

    Czech Academy of Sciences Publication Activity Database

    Drabik, M.; Kozak, T.; Ležal, Dimitrij; Poulain, M.; Kalužný, J.

    2002-01-01

    Roč. 67, č. 1 (2002), s. 223-227 ISSN 1418-2874 Institutional research plan: CEZ:AV0Z4032918 Keywords : glass transition * Pr dopand * sulfide Ge-Ga glasses Subject RIV: CA - Inorganic Chemistry Impact factor: 0.598, year: 2002

  1. Volatility in energy prices

    International Nuclear Information System (INIS)

    Duffie, D.

    1999-01-01

    This chapter with 58 references reviews the modelling and empirical behaviour of volatility in energy prices. Constant volatility and stochastic volatility are discussed. Markovian models of stochastic volatility are described and the different classes of Markovian stochastic volatility model are examined including auto-regressive volatility, option implied and forecasted volatility, Garch volatility, Egarch volatility, multivariate Garch volatility, and stochastic volatility and dynamic hedging policies. Other volatility models and option hedging are considered. The performance of several stochastic volatility models as applied to heating oil, light oil, natural gas, electricity and light crude oil are compared

  2. Study on off-odor volatiles of irradiated packaged raw pork

    International Nuclear Information System (INIS)

    Lin Ruotai; Geng Shengrong; Liu Yangmin

    2008-01-01

    Analysing the compositions of off-odor volatiles in irradiated refrigerated vacuum-packaged pork and research on its origin. First, the off-odor volatiles were collected by a cooled via in liquid nitrogen, then the main composition of off-odor volatiles were analyzed by gas chromatograph mass spectrometry (GC-MS). The main composition of off-odor volatiles are dimethyl disulfide, dimethyl sulfide, dimethyl trisulfide, methanethiol and S-methyl thioacetate. The off-odor volatiles come from irradiated cystine, methionine and VB1. The main composition of off-odor volatiles are S-containing compounds from irradiated S-containing amino acid and VB1

  3. Stochastic volatility of volatility in continuous time

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole; Veraart, Almut

    This paper introduces the concept of stochastic volatility of volatility in continuous time and, hence, extends standard stochastic volatility (SV) models to allow for an additional source of randomness associated with greater variability in the data. We discuss how stochastic volatility...... of volatility can be defined both non-parametrically, where we link it to the quadratic variation of the stochastic variance process, and parametrically, where we propose two new SV models which allow for stochastic volatility of volatility. In addition, we show that volatility of volatility can be estimated...

  4. Analyse av LOD-tiltak

    OpenAIRE

    Kunduraci, Meltem

    2016-01-01

    Endrede klimatiske forhold og større urbanisering medfører økte oversvømmelsesskader i urbane områder. Ekstreme nedbørhendelser opptrer oftere og kraftigere. Utbygging med tette flater hindrer infiltrasjon til grunnen. Den naturlige utjevningen av overvann reduseres. Dette resulterer i økende belastninger på det eksisterende avløpssystemet. Kapasiteten på avløpsnettet er mange steder overbelastet og er ikke i stand til å håndtere overvannsmengder under styrtregn. Lokal overvannsdisponering el...

  5. PREPARATION FOR RETIREMENT - AVS SEMINAR

    CERN Multimedia

    Social Service

    2001-01-01

    The 500 or so participants in the fifth Preparation for Retirement seminar held at the end of March were unfortunately deprived of the planned session on the AVS due to the unavailability of the Director of the Caisse Cantonale Genevoise de Compensation (CCGC). We have since had formal confirmation that because of an extra workload due to important changes in the Swiss tax and social legislation and the implementation this summer of the maternity insurance in Geneva, the CCGC has suspended its participation in preparation for retirement seminars in the international organisations for the time being. Conscious of the necessity of offering a session dedicated to the AVS, it is with pleasure that we can inform you that one of our legal advisers, Mr Lorenz Stampfli, has accepted to lead this session. In order to allow for adequate preparation we have reserved the following date: Wednesday 26 September from 14.00 to 16.00 in the Main Amphitheatre The session will be open to all people already registered and any o...

  6. Arctic Visiting Speakers Series (AVS)

    Science.gov (United States)

    Fox, S. E.; Griswold, J.

    2011-12-01

    The Arctic Visiting Speakers (AVS) Series funds researchers and other arctic experts to travel and share their knowledge in communities where they might not otherwise connect. Speakers cover a wide range of arctic research topics and can address a variety of audiences including K-12 students, graduate and undergraduate students, and the general public. Host applications are accepted on an on-going basis, depending on funding availability. Applications need to be submitted at least 1 month prior to the expected tour dates. Interested hosts can choose speakers from an online Speakers Bureau or invite a speaker of their choice. Preference is given to individuals and organizations to host speakers that reach a broad audience and the general public. AVS tours are encouraged to span several days, allowing ample time for interactions with faculty, students, local media, and community members. Applications for both domestic and international visits will be considered. Applications for international visits should involve participation of more than one host organization and must include either a US-based speaker or a US-based organization. This is a small but important program that educates the public about Arctic issues. There have been 27 tours since 2007 that have impacted communities across the globe including: Gatineau, Quebec Canada; St. Petersburg, Russia; Piscataway, New Jersey; Cordova, Alaska; Nuuk, Greenland; Elizabethtown, Pennsylvania; Oslo, Norway; Inari, Finland; Borgarnes, Iceland; San Francisco, California and Wolcott, Vermont to name a few. Tours have included lectures to K-12 schools, college and university students, tribal organizations, Boy Scout troops, science center and museum patrons, and the general public. There are approximately 300 attendees enjoying each AVS tour, roughly 4100 people have been reached since 2007. The expectations for each tour are extremely manageable. Hosts must submit a schedule of events and a tour summary to be posted online

  7. VISUALISERINGSTAVLA : Visualisering av Kanban boards

    OpenAIRE

    Y. F. Sam, Adam

    2013-01-01

    Hos många företag används whiteboards för att visualisera arbetsprocessen. En vanlig metodik för detta är så kallade Kanban boards, ett system av tabeller och lappar för att indikera olika avvikelser eller moment i projekt med datum och annan relevant information. Företag kan även välja att använda en mjukvara som simulerar samma metodik, ett exempel på detta är så kallade Elektroniska kanban boards. I detta arbete har båda dessa metoder (whiteboard samt en digital lösning) observerats hos tr...

  8. Sulfide Mineral Surfaces

    International Nuclear Information System (INIS)

    Rosso, Kevin M.; Vaughan, David J.

    2006-01-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

  9. Sulfide Mineral Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by

  10. GC-MS analysis of off-odor volatiles from irradiated pork

    International Nuclear Information System (INIS)

    Lin Ruotai; Geng Shengrong; Zhang Jinmu; Chen Yuxia; Liu Yangmin; Wang Liping; Wang Hong; Xu Ying; Yao Side

    2007-01-01

    The main compounds of off-odor volatiles from irradiated refrigerated vacuum-packaged pork were analyzed by gas chromatograph/mass spectrometer (GC-MS). The analytical results showed that the main compounds of off-odor volatiles were dimethyl disulfide, dimethyl sulfide, dimethyl trisulfide, S-methyl thioacetate, and methanethiol. It was proved that the off-odor volatile came from irradiated S-containing amino acid and thiamin. (authors)

  11. Volatile metabolites in the exhaled breath of healthy volunteers: their levels and distributions

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Turner, C.; Španěl, Patrik

    2007-01-01

    Roč. 1, - (2007), 014004R1-014004R12 ISSN 1752-7155 Institutional research plan: CEZ:AV0Z40400503 Keywords : volatile metabolities * SIFT-MS * breath analysis Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Effekt av ulike desinfeksjonsstrategier mot Listeria monocytogenes

    OpenAIRE

    Fossmo, Sabine

    2013-01-01

    Kontroll med bakterier som Listeria utgjør en stor utfordring for mange matprodusenter. Listeria monocytogenes er hovedsakelig et produksjonshygienisk problem, forbedret hygiene kan derfor være tiltak for å redusere overlevelse og smitteoverføring av bakterien i produksjonsmiljø. Hensikten med forsøkene i oppgaven var å undersøke effekten av ulike desinfeksjonsstrategier på drap av L. monocytogenes, både når bakteriene var i biofilm og i suspensjon. Dette inkluderte bruk av tradisjonelle desi...

  13. Pricing Volatility Referenced Assets

    Directory of Open Access Journals (Sweden)

    Alan De Genaro Dario

    2006-12-01

    Full Text Available Volatility swaps are contingent claims on future realized volatility. Variance swaps are similar instruments on future realized variance, the square of future realized volatility. Unlike a plain vanilla option, whose volatility exposure is contaminated by its asset price dependence, volatility and variance swaps provide a pure exposure to volatility alone. This article discusses the risk-neutral valuation of volatility and variance swaps based on the framework outlined in the Heston (1993 stochastic volatility model. Additionally, the Heston (1993 model is calibrated for foreign currency options traded at BMF and its parameters are used to price swaps on volatility and variance of the BRL / USD exchange rate.

  14. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  15. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    OpenAIRE

    Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

    2011-01-01

    Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

  16. Efficient Software HEVC to AVS2 Transcoding

    Directory of Open Access Journals (Sweden)

    Yucong Chen

    2016-09-01

    Full Text Available The second generation of Audio and Video coding Standard (AVS is developed by the IEEE 1857 Working Group under project 1857.4 and was standardized in 2016 by the AVS Working Group of China as the new broadcasting standard AVS2. High Efficient Video Coding (HEVC is the newest global video coding standard announced in 2013. More and more codings are migrating from H.264/AVC to HEVC because of its higher compression performance. In this paper, we propose an efficient HEVC to AVS2 transcoding algorithm, which applies a multi-stage decoding information utilization framework to maximize the usage of the decoding information in the transcoding process. The proposed algorithm achieves 11×–17× speed gains over the AVS2 reference software RD 14.0 with a modest BD-rate loss of 9.6%–16.6%.

  17. Arvelig hemokromatose - nytten av screening

    Directory of Open Access Journals (Sweden)

    Arne Åsberg

    2009-10-01

    Full Text Available Arvelig hemokromatose fører til jernopphopning i kroppen, men gir sjelden alvorlig helseskade. Nesten alle hemokromatosepasienter i vårt land er homozygote for C282Y-mutasjonen i HFE-genet. Omtrent 7 per 1000 innbyggere har denne genotypen. Alvorlig syke blir bare omkring 5-15% av homozygote menn og nesten ingen kvinner. Likevel er det holdepunkter for at screening for hemokromatose blant friske, yngre menn kan være kostnadseffektivt. Det er relativt lett å påvise om en person er disponert for sykdommen, i god tid før den bryter ut, og forebyggende behandling er billig og effektiv. Imidlertid kan vi ikke forutsi hvilke screeningpositive personer som ubehandlet får alvorlig sykdom. Et kontrollert forsøk med screening bør gjennomføresHereditary hemochromatosis – benefits of screening. Hereditary hemochromatosis leads to iron accumulation in the body; however, serious illness due to hemochromatosis is rare. In Norway, almost all patients with hemochromatosis are homozygous for the C282Ymutation in the HFE-gene, a genotype carried by about 7 per 1000 inhabitants. Serious complications are seen in only about 5-15% of homozygous men and in very few women. Nevertheless, screening young men for hemochromatosis may be cost-effective. Detecting predisposed men is relatively straightforward, and prophylactic treatment is cheap and effective. However, we can not predict, among screen-positive men, the few who untreated will become seriously ill. A controlled screening trial should be conducted.

  18. Volatile Sulfur Compounds from Livestock Production

    DEFF Research Database (Denmark)

    Kasper, Pernille

    . Presently, the development of abatement technologies is limited by the lack of an accurate and reliable method for quantifying the effect on odor. To measure the impact of air cleaning techniques on perceived odor, common practice in Europe is to store odor samples in sample bags and quantify them......Volatile sulfur compounds, i.e. hydrogen sulfide, methanethiol and dimethyl sulfide have been identified as key odorants in livestock production due to their high concentration levels and low odor threshold values. At the same time their removal with abatement technologies based on mass transfer...... from a gas phase to a liquid phase, e.g. biotrickling filters, is decelerated due to their low partitioning coefficients. This can significantly limit the odor reduction obtained with these technologies. The present study examines the possibility of adding metal catalysts to enhance the mass transfer...

  19. Preparation of Mo/Al2O3 Sulfide Catalysts Modified by Ir Nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Cinibulk, Josef; Vít, Zdeněk

    2002-01-01

    Roč. 143, - (2002), s. 443-451 ISSN 0167-2991. [International Symposium Scientific Bases for the Preparation of Heterogeneous Catalysts /8./. Louvain-la-Neuve, 09.09.2002-12.09.2002] R&D Projects: GA AV ČR IAA4072103 Keywords : catalysts modified * sulfide catalysts * Mo/Al2O3 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.468, year: 2002

  20. Undersøkelse av forekomst av elvemusling i Grense Jakobselv

    OpenAIRE

    Aspholm, Paul Eric; Brodersen, Christopher; Nilsen, Even; Terentjev, Nikolai; Kashulin, Nikolai; Polykarpova, Natalia

    2017-01-01

    Sensommeren 2014 ble det midtre partiet av Grense Jakobselv fra Elvheim til sørenden av Lasaruskulpen undersøkt for forekomst av elvemusling. De nedre delene av Grense Jakobselv og sideelver har vært undersøkt tidligere (2003 og 2005). I disse tidligere undersøkelsene har det ikke blitt påvist elvemusling eller skall av døde muslinger. Under undersøkelsen i 22. – 23. juli 2014 ble de første elvemuslingene funnet like oppstrøms Sandvasselva. Denne undersøkelsen omfattet i alt 12 forhåndsutvalg...

  1. Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

    Czech Academy of Sciences Publication Activity Database

    D'Ulivo, A.; Dědina, Jiří; Mester, Z.; Sturgeon, R. E.; Wang, Q.; Welz, B.

    2011-01-01

    Roč. 83, č. 6 (2011), s. 1283-1340 ISSN 0033-4545 Institutional research plan: CEZ:AV0Z40310501 Keywords : borane complexes * chemical generation of volatile hydrides (CHG) * volatile hydrides Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.789, year: 2011

  2. The Variation Characteristic of Sulfides and VOSc in a Source Water Reservoir and Its Control Using a Water-Lifting Aerator

    Directory of Open Access Journals (Sweden)

    Jian-Chao Shi

    2016-04-01

    Full Text Available Sulfides and volatile organic sulfur compounds (VOSc in water are not only malodorous but also toxic to humans and aquatic organisms. They cause serious deterioration in the ecological environment and pollute drinking water sources. In the present study, a source water reservoir—Zhoucun Reservoir in East China—was selected as the study site. Through a combination of field monitoring and in situ release experiments of sulfides, the characteristics of seasonal variation and distribution of sulfides and VOSc in the reservoir were studied, and the cause of the sulfide pollution was explained. The results show that sulfide pollution was quite severe in August and September 2014 in the Zhoucun Reservoir, with up to 1.59 mg·L−1 of sulfides in the lower layer water. The main source of sulfides is endogenous pollution. VOSc concentration correlates very well with that of sulfides during the summer, with a peak VOSc concentration of 44.37 μg·L−1. An installed water-lifting aeration system was shown to directly oxygenate the lower layer water, as well as mix water from the lower and the upper layers. Finally, the principle and results of controlling sulfides and VOSc in reservoirs using water-lifting aerators are clarified. Information about sulfides and VOSc fluctuation and control gained in this study may be applicable to similar reservoirs, and useful in practical water quality improvement and pollution prevention.

  3. Fractional order absolute vibration suppression (AVS) controllers

    Science.gov (United States)

    Halevi, Yoram

    2017-04-01

    Absolute vibration suppression (AVS) is a control method for flexible structures. The first step is an accurate, infinite dimension, transfer function (TF), from actuation to measurement. This leads to the collocated, rate feedback AVS controller that in some cases completely eliminates the vibration. In case of the 1D wave equation, the TF consists of pure time delays and low order rational terms, and the AVS controller is rational. In all other cases, the TF and consequently the controller are fractional order in both the delays and the "rational parts". The paper considers stability, performance and actual implementation in such cases.

  4. Macro-fiscal volatility and the composition of public spending

    Czech Academy of Sciences Publication Activity Database

    Riscado, S. M.; Stančík, Juraj; Välilä, T.

    2011-01-01

    Roč. 32, č. 4 (2011), s. 511-538 ISSN 0143-5671 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : tax volatility * public investment * public consumption Subject RIV: AH - Economics Impact factor: 0.486, year: 2011

  5. Exchange rate volatility and regime change: Visegrad comparison

    Czech Academy of Sciences Publication Activity Database

    Kočenda, Evžen; Valachy, J.

    -, č. 7 (2006), s. 1-36 R&D Projects: GA ČR GA402/06/1293 Institutional research plan: CEZ:AV0Z70850503 Keywords : exchange rate regime s * volatility * transition Subject RIV: AH - Economics http://deepblue.lib.umich.edu/bitstream/2027.42/21616/1/IPC-working-paper-007-KocendaValachy.pdf

  6. A Reaction Involving Oxygen and Metal Sulfides.

    Science.gov (United States)

    Hill, William D. Jr.

    1986-01-01

    Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

  7. A study on the composition of off-odor volatiles in irradiated pork

    International Nuclear Information System (INIS)

    Lin Ruotai; Geng Shengrong; Zhang Jinmu; Chen Yuxia; Liu Yangmin; Wang Liping; Wang Hong; Xu Ying; Yao Side

    2006-01-01

    The purpose of this study was to lay a foundation on generation mechanisms and removal method of off-odor of irradiated meat products. Vacuum-package and refrigerated raw pork samples were irradiated with 60 Co γ-rays. Off-odor volatiles from the irradiated pork samples were taken in by a vacuum system and were collected by a cooled vial in liquid nitrogen. At the same time, the source of off-odor generation was investigated. Main compositions of off-odor volatiles of the irradiated pork were analyzed with gas chromatograph mass spectrometry (GC-MS). The results showed that main compositions of the off-odor volatiles were dimethyl disulfide, dimethyl sulfide, dimethyl trisulfide, methanethiol and S-methyl thioacetate, and the off-odor volatiles came from sulfide-containing amino acid and thiamin of the irradiated pork. Sulfide-containing compounds increased with the dose in the range of 0-3 kGy, and decreased with the refrigeration time, but changed from different kinds of the package. The non-irradiated samples, however, contained just a little sulfide-containing compounds of dimethyl sulfide and vangardbt. (authors)

  8. Embolization of AV intra-hepatic fistulas

    Energy Technology Data Exchange (ETDEWEB)

    Mallarini, G; Saitta, S; Cariati, M; Nicorelli, M; de Caro, G

    1982-05-01

    The use of therapeutic embolization in a case of hepatic AV fistula with portal flow inversion and portal hypertension is described. Indications, technique and an illustrative case followed up for one year after the intervention are presented.

  9. Sulfide-conducting solid electrolytes

    International Nuclear Information System (INIS)

    Kalinina, L.A.; Shirokova, G.I.; Murin, I.V.; Ushakova, Yu.N.; Fominykh, E.G.; Lyalina, M.Yu.

    2000-01-01

    Feasibility of sulfide transfer in phases on the basis of BaZrS 3 and MLn 2 S 4 ( M = Ca, Ba; Ln = La, Y, Tm, Nd, Sm, Pr) is considered. Solid solution regions on the basis of ternary compounds are determined. Systematic study of the phases is carried out making use of the methods of conductometry, emf in chemical concentration chains without/with transfer, potentiostatic chronoamperometry. Possible mechanism of defect formation during successive alloying of ternary sulfides by binary ones in suggested [ru

  10. Evaluering av KS’ ulike ledelsesutviklingstilbud for kommunesektoren

    OpenAIRE

    Haave, Hanne; Hafting, Tore; Haugstveit, Yngve; Odden, Sigrun

    2008-01-01

    Norsk: Denne rapporten presenterer en evaluering av ledelsesutviklingstilbud i KS. De ledelsesutviklingsprogrammene som omfattes av evalueringen er i første rekke: Rådmentor, Krefter i bevegelse, Jazz endringsledelse, Medarbeiderskap, B-link og Skreddersydde program. Evalueringens hovedproblemstilling er å undersøke om og i hvilken grad KS’ ledelsesutviklingstilbud samsvarer med dominerende perspektiver og mål i KS’ arbeidsgiverstrategi «Stolt og unik, arbeidsgiverstrateg...

  11. Endogenous Lunar Volatiles

    Science.gov (United States)

    McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Boyce, J. W.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Magna, T.; Ni, P.; Tartese, R.; hide

    2017-01-01

    The chapter will begin with an introduction that defines magmatic volatiles (e.g., H, F, Cl, S) versus geochemical volatiles (e.g., K, Rb, Zn). We will discuss our approach of understanding both types of volatiles in lunar samples and lay the ground work for how we will determine the overall volatile budget of the Moon. We will then discuss the importance of endogenous volatiles in shaping the "Newer Views of the Moon", specifically how endogenous volatiles feed forward into processes such as the origin of the Moon, magmatic differentiation, volcanism, and secondary processes during surface and crustal interactions. After the introduction, we will include a re-view/synthesis on the current state of 1) apatite compositions (volatile abundances and isotopic compositions); 2) nominally anhydrous mineral phases (moderately to highly volatile); 3) volatile (moderately to highly volatile) abundances in and isotopic compositions of lunar pyroclastic glass beads; 4) volatile (moderately to highly volatile) abundances in and isotopic compositions of lunar basalts; 5) volatile (moderately to highly volatile) abundances in and isotopic compositions of melt inclusions; and finally 6) experimental constraints on mineral-melt partitioning of moderately to highly volatile elements under lunar conditions. We anticipate that each section will summarize results since 2007 and focus on new results published since the 2015 Am Min review paper on lunar volatiles [9]. The next section will discuss how to use sample abundances of volatiles to understand the source region and potential caveats in estimating source abundances of volatiles. The following section will include our best estimates of volatile abundances and isotopic compositions (where permitted by available data) for each volatile element of interest in a number of important lunar reservoirs, including the crust, mantle, KREEP, and bulk Moon. The final section of the chapter will focus upon future work, outstanding questions

  12. Nanostructured metal sulfides for energy storage

    Science.gov (United States)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-08-01

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  13. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  14. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S...

  15. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  16. Outcomes of AV Fistulas and AV Grafts after Interventional Stent-Graft Deployment in Haemodialysis Patients

    Energy Technology Data Exchange (ETDEWEB)

    Schmelter, Christopher, E-mail: christopher.schmelter@klinikum-ingolstadt.de; Raab, Udo, E-mail: udo.raab@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany); Lazarus, Friedrich, E-mail: friedrich.lazarus@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Nephrology (Germany); Ruppert, Volker, E-mail: volker.ruppert@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Vascular Surgery (Germany); Vorwerk, Dierk, E-mail: dierk.vorwerk@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany)

    2015-08-15

    PurposeThe study was designed to assess outcomes of arteriovenous (AV) accesses after interventional stent-graft deployment in haemodialysis patients.Materials and Methods63 haemodialysis patients with 66 AV fistulas and AV grafts were treated by interventional stent-graft deployment from 2006 to 2012 at our hospital. Data of these patients were retrospectively analysed for location of deployed stent-grafts, occurrence and location of (re-)stenosis and (re-)thrombosis. Complex stenosis was the most frequent indication for stent-graft deployment (45.5 %), followed by complications of angioplasty with vessel rupture or dissection (31.8 %).ResultsA high rate of procedural success was achieved (98.5 %). The most frequent location of the deployed stent-graft was the draining vein (66.7 %). Stent-graft deployment was more frequent in AV grafts than in AV fistulas. Primary patency was 45.5 % at 6 month, 31.3 % at 12 month and 19.2 % at 24 month. Primary patency was significantly better for AV fistulas than for AV grafts with deployed stent-grafts. Patency of the deployed stent-graft was much better than overall AV access primary patency with deployed stent-graft. Re-stenosis with thrombosis was the most frequent indication for re-intervention. Most frequent location of re-stenosis was the draining vein (37.1 %), followed by stenosis at the AV access (29.5 %) and the deployed stent-graft (23.5 %).ConclusionRe-stenosis and re-thrombosis remain frequent in AV fistulas and AV grafts in haemodialysis patients despite stent-graft deployment. Re-stenosis of the deployed stent-graft is, only in the minority of the cases, responsible for AV access dysfunction.

  17. Analyse av overvannsnettet i Ås sentrum ved bruk av simuleringsprogrammet SWMM

    OpenAIRE

    Dvergsnes, Eirunn

    2016-01-01

    Jorden står ovenfor klimaendringer med økende temperaturer og en hyppigere forekomst av intense nedbørshendelser. For overvannssystemer i urbane strøk er den økte nedbørintensiteten en stor utfordring. Urbanisering har medført en stor andel tette flater, og lukking av naturlige bekkesystemer. Dette krever en raskere bortledning av regnvannet gjennom rør i bakken. Store deler av det norske overvannssystemet er ikke dimensjonert etter dagens norske standard. Denne ble revidert se...

  18. Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Ma, Wenjuan; Guo, Yadong; Wang, Aijie; Wang, Qilin; Lee, Duu-Jong

    2016-02-01

    Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S(0)), carbon dioxide, and nitrogen-containing gas (such as N2) at NaCl concentration of 35-70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S(0) conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity.

  19. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  20. Asymmetric Realized Volatility Risk

    Directory of Open Access Journals (Sweden)

    David E. Allen

    2014-06-01

    Full Text Available In this paper, we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive. Even though returns standardized by ex post quadratic variation measures are nearly Gaussian, this unpredictability brings considerably more uncertainty to the empirically relevant ex ante distribution of returns. Explicitly modeling this volatility risk is fundamental. We propose a dually asymmetric realized volatility model, which incorporates the fact that realized volatility series are systematically more volatile in high volatility periods. Returns in this framework display time varying volatility, skewness and kurtosis. We provide a detailed account of the empirical advantages of the model using data on the S&P 500 index and eight other indexes and stocks.

  1. Occurrence and abatement of volatile sulfur compounds during biogas production.

    Science.gov (United States)

    Andersson, Fräs Annika T; Karlsson, Anna; Svensson, Bo H; Ejlertsson, Jörgen

    2004-07-01

    Volatile sulfur compounds (VSCs) in biogas originating from a biogas production plant and from a municipal sewage water treatment plant were identified. Samples were taken at various stages of the biogas-producing process, including upgrading the gas to vehicle-fuel quality. Solid-phase microextraction was used for preconcentration of the VSCs, which were subsequently analyzed using gas chromatography in combination with mass spectrometry. Other volatile organic compounds present also were identified. The most commonly occurring VSCs in the biogas were hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide, and hydrogen sulfide was not always the most abundant sulfur (S) compound. Besides VSCs, oxygenated organic compounds were commonly present (e.g., ketones, alcohols, and esters). The effect of adding iron chloride to the biogas reactor on the occurrence of VSCs also was investigated. It was found that additions of 500-g/m3 substrate gave an optimal removal of VSCs. Also, the use of a prefermentation step could reduce the amount of VSCs formed in the biogas process. Moreover, in the carbon dioxide scrubber used for upgrading the gas, VSCs were removed efficiently, leaving traces (ppbv levels). The scrubber also removed other organic compounds.

  2. Veileder for kravspesifikasjon for leie av kontorarealer

    DEFF Research Database (Denmark)

    Førland-Larsen, Arne

    Investorer og leietakere blir stadig mer interessert i helse- og miljøkvaliteter. Men kunnskapen er lav hos de fleste om hva de skal etterspørre og hvordan slike kvaliteter kan dokumenteres. Meglere har en viktig rolle som formidler av kvaliteter. Grønn Byggallianse har i samarbeid med blant annet...... Norsk Eiendom, Enova og NGBC utarbeidet en mal for standard kravspesifikasjon for leie av kontorlokaler. Målet med malen er å bidra til at leietager får det produktet han trenger til riktig pris og at man unngår unødig miljøbelastning. Målet er videre at å bidra og stimulere til, at innleie....../utleie prosesser startes med en dialogbasert prosess. Standarden er tenkt som et hjelpemiddel til en systematisk gjennomgang av, og diskusjon av hvilke kvaliteter som har prioritet, høy, middel eller lav prioritet for leietaker. Resultatet av dialog og diskusjon fastlegger endelige krav til kvalitet og...

  3. Effect of H2S on Pyridine HDN over Ir, Mo and Ir-Mo/Al2O3 Sulfide Catalysts

    Czech Academy of Sciences Publication Activity Database

    Vít, Zdeněk; Cinibulk, Josef

    2002-01-01

    Roč. 77, č. 1 (2002), s. 43-49 ISSN 0133-1736 R&D Projects: GA AV ČR IAA4072103 Keywords : HDN * Mo sulfide * iridium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.398, year: 2002

  4. Endogenous Lunar Volatiles

    Science.gov (United States)

    McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Anand, M.; Boyce, J. W.; Burney, D.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Klima, R. L.; Magna, T.; Ni, P.; Steenstra, E.; Tartèse, R.; Vander Kaaden, K. E.

    2018-04-01

    This abstract discusses numerous outstanding questions on the topic of endogenous lunar volatiles that will need to be addressed in the coming years. Although substantial insights into endogenous lunar volatiles have been gained, more work remains.

  5. Nonvolatile, semivolatile, or volatile: redefining volatile for volatile organic compounds.

    Science.gov (United States)

    Võ, Uyên-Uyén T; Morris, Michael P

    2014-06-01

    Although widely used in air quality regulatory frameworks, the term "volatile organic compound" (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and US. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products. The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test

  6. Normalization for Implied Volatility

    OpenAIRE

    Fukasawa, Masaaki

    2010-01-01

    We study specific nonlinear transformations of the Black-Scholes implied volatility to show remarkable properties of the volatility surface. Model-free bounds on the implied volatility skew are given. Pricing formulas for the European options which are written in terms of the implied volatility are given. In particular, we prove elegant formulas for the fair strikes of the variance swap and the gamma swap.

  7. Realized Volatility Risk

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); M. Scharth (Marcel)

    2013-01-01

    textabstractIn this paper we document that realized variation measures constructed from highfrequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive.

  8. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    Directory of Open Access Journals (Sweden)

    Sanchi Nenkova

    2011-04-01

    Full Text Available Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of copper sulfides in the lignocellulosic matrix were investigated. The modification with a system of 2 components: cupric sulfate pentahydrate (CuSO4. 5H2O and sodium thiosulfate pentahydrate (Na2S2O3.5H2O for wood fibers is preferred. Optimal parameters were established for the process: 40 % of the reduction system; hydromodule M=1:6; and ratio of cupric sulfate pentahydrate:sodium thiosulfate pentahydrate = 1:2. The coordinative connection of copper ions with oxygen atoms of cellulose OH groups and aromatic nucleus in lignin macromolecule was observed.

  9. Chemical dissolution of sulfide minerals

    Science.gov (United States)

    Chao, T.T.; Sanzolone, R.F.

    1977-01-01

    Chemical dissolution treatments involving the use of aqua regia, 4 N HNO3, H2O2-ascorbic acid, oxalic acid, KClO3+HCl, and KClO3+HCl followed by 4 N HNO3 were applied to specimens of nine common sulfide minerals (galena, chalcopyrite, cinnabar, molybdenite, orpiment, pyrite, stibnite, sphalerite, and tetrahedrite) mixed individually with a clay loam soil. The resultant decrease in the total sulfur content of the mixture, as determined by using the Leco induction furnace, was used to evaluate the effectiveness of each chemical treatment. A combination of KClO3+HCl followed by 4 N HNO3 boiling gently for 20 min has been shown to be very effective in dissolving all the sulfide minerals. This treatment is recommended to dissolve metals residing in sulfide minerals admixed with secondary weathering products, as one step in a fractionation scheme whereby metals in soluble and adsorbed forms, and those associated with organic materials and secondary oxides, are first removed by other chemical extractants.

  10. Å speide etter spiritualitet. En analyse av spiritualitetsbegrepet i speiderbevegelsen

    OpenAIRE

    Holmefjord, Aina

    2015-01-01

    Denne masteroppgaven inneholder analyser av speiderbevegelsens bruk av begrepet "spiritualitet" i to bøker skrevet av bevegelsens grunnlegger; "Scouting for Boys" og "Rovering to Succes" og to dokumenter av The World Organization of he Scoutmovement . Robert Baden-Powell grunnlag speiderbevegelsen i 1908 og hans litteratur og bøker publisert på tidlig 1900-tallet setter rammeverk for mye av dagens speiderbevegelses ideologi og visjon. Speiderbevegelsen har et r...

  11. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    Sulfide intrusion in seagrasses represents a global threat to seagrasses and thereby an important parameter in resilience of seagrass ecosystems. In contrast seegrasses colonize and grow in hostile sediments, where they are constantly exposed to invasion of toxic gaseous sulfide. Remarkably little...... strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis, tracing sulfur compounds combined with ecosystem parameters we found different spatial, intraspecific and interspecific strategies to cope with sulfidic sediments. 1...... not present in terrestrial plants at that level. Sulfide is not necessarily toxic but used as sulfur nutrition, presupposing healthy seagrass ecosystems that can support detoxification mechanisms. Presence or absence of those mechanisms determines susceptibility of seagrass ecosystems to sediment sulfide...

  12. Tilsetningsstoff og tekniske hjelpestoff ved produksjon av filet av hvitfisk. Faglig sluttrapport

    OpenAIRE

    Lorentzen, Grete Elisabeth

    2017-01-01

    Målsettingen med dette prosjektet har vært å øke den generelle kunnskapen om bruk av tilsetningsstoffer og tekniske hjelpestoffer ved produksjon av hvitfiskfilet. I prosjektet er det gjennomført et litteraturstudium på hvilken effekt ulike tilsetningsstoffer har på fiskefilet. Deretter er det laget en veileder hvor målet har vært å gi en lettfattet og oversiktlig informasjon om hvilke tilsetningsstoffer det er lov å bruke, hvilken effekt de har, og eksempler på praktisk bruk av tilsetningssto...

  13. Bruk av urtemedisiner blant gravide i Mali : Intervju av 72 healere i Bamako, Siby og Dioila

    OpenAIRE

    Al-Zayadi, Waled

    2012-01-01

    WHO’s rapport fra 2001 viser til at hele 75 % av Mali sin populasjon bruker tradisjonell medisin. Det er beregnet til å være 1 medisinmann pr 500 innbyggere. Hovedmålet med denne oppgaven var å undersøke tradisjonelle medisinmenns behandling av sykdom og plager i svangerskapet i Mali. Det er lite som vites om bruk av urtemedisiner blant gravide i Mali. Det er heller ingen studier gjort fra healerens side. Studien var med på å kartlegge hvilke urter som brukes til den enkelte plagen. I ette...

  14. Neutron diffraction investigations of the superionic conductors lithium sulfide and sodium sulfide

    International Nuclear Information System (INIS)

    Altorfer, F.

    1990-03-01

    Statics and dynamics of the superionic conductors lithium sulfide and sodium sulfide were investigated using the following experimental methods: elastic scattering on sodium sulfide powder in the temperature range 20 - 1000 C, elastic scattering on a lithium sulfide single crystal in the temperature range 20 - 700 C, inelastic scattering on a 7 Li 2 S single crystal at 10 K. 34 figs., 2 tabs., 10 refs

  15. Heterogeneous ion-exchange polyethylene-based membranes with sulfonated poly(1,4-phenylene sulfide) particles

    Czech Academy of Sciences Publication Activity Database

    Schauer, Jan; Brožová, Libuše; Pientka, Zbyněk; Bouzek, K.

    2006-01-01

    Roč. 200, 1-3 (2006), s. 632-633 ISSN 0011-9164. [Conference Euromembrane. Giardini Naxos - Taormina, 24.09.2006-28.09.2006] R&D Projects: GA ČR GA203/05/0080 Institutional research plan: CEZ:AV0Z40500505 Keywords : ion-exchange membrane * poly(phenylene sulfide) * fuel cell Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.917, year: 2006

  16. Sulfidation behavior of Fe20Cr alloys

    International Nuclear Information System (INIS)

    Pillis, Marina Fuser

    2001-01-01

    Alloys for use in high temperature environments rely on the formation of an oxide layer for their protection. Normally, these protective oxides are Cr 2 O 3 , Al 2 O 3 and, some times, SiO 2 . Many industrial gaseous environments contain sulfur. Sulfides, formed in the presence of sulfur are thermodynamically less stable, have lower melting points and deviate much more stoichiometrically, compared to the corresponding oxides. The mechanism of sulfidation of various metals is as yet not clear, in spite of the concerted efforts during the last decade. To help address this situation, the sulfidation behavior of Fe20Cr has been studied as a function of compositional modifications and surface state of the alloy. The alloys Fe20Cr, Fe20Cr0.7Y, Fe20Cr5Al and Fe20Cr5Al0.6Y were prepared and three sets of sulfidation tests were carried out. In the first set, the alloys were sulfidized at 700 deg C and 800 deg C for 10h. In the second set, the alloys were pre-oxidized at 1000 deg C and then sulfidized at 800 deg C for up to 45h. In the third set of tests, the initial stages of sulfidation of the alloys was studied. All the tests were carried out in a thermobalance, in flowing H 2 /2%H 2 S, and the sulfidation behavior determined as mass change per unit area. Scanning electron microscopy coupled to energy dispersive spectroscopy and X-ray diffraction analysis were used to characterize the reaction products. The addition of Y and Al increased sulfidation resistance of Fe20Cr. The addition of Y altered the species that diffused predominantly during sulfide growth. It changed from predominant cationic diffusion to predominant anionic diffusion. The addition of Al caused an even greater increase in sulfidation resistance of Fe20Cr, with the parabolic rate constant decreasing by three orders of magnitude. Y addition to the FeCrAl alloy did not cause any appreciable alteration in sulfidation resistance. Pre-oxidation of the FeCrAl and FeCrAlY alloys resulted in an extended

  17. Forskere i norske avisers dekning av skole

    Directory of Open Access Journals (Sweden)

    Emilia Andersson-Bakken

    2015-10-01

    Full Text Available Skolen er stadig i medienes søkelys, og i denne artikkelen ser vi nærmere på hvordan forskere bidrar med sine fagkunnskaper i skoledebatten i mediene. Den problemstillingen vi ønsker å besvare, er: Hvilken rolle har forskere i norske avisers dekning av skole? For å svare på dette har vi gjort en analyse av samtlige artikler om skole i VG, Bergens Tidende og Aftenposten i 2013. Resultatene viser at det forekommer en navngitt forsker i ca. 12 % av avisenes artikler om skole (209 av 1712 artikler. Det er imidlertid forskjell mellom avisene, og i VG opptrer det forskere i ca. 24 % av artiklene om skole, mens andelen både i Aftenposten og BT er ca. 11 %. Undersøkelsen viser videre at det er mange forskere som får mulighet til å uttale seg om skole i disse tre avisene, men det store flertallet av disse uttaler seg kun én gang. Vi fant også at forskere ofte uttaler seg om rammene for skolens undervisningsvirksomhet, og sjelden om det som foregår i klasserommene. Resultatene av vår empiriske undersøkelse stemmer i stor grad overens med hovedtendensene i tidligere studier av forskere i media, noe som indikerer at forskernes rolle i norske avisers skoledekning ikke skiller seg markant ut fra den rollen forskere har i media generelt. Våre resultater peker imidlertid på én viktig forskjell: Forskere ser ut til å være uvanlig godt synlige i norske avisers dekning av skole.Nøkkelord: skoleforskning, media, forskningsformidlingAbstractSchool is a frequently debated topic in the media, and this article investigates how researchers contribute with their knowledge in this media debate. The research question is: What characterizes researcher participation in Norwegian newspaper coverage of school? To answer this question we have analyzed all articles about school in the Norwegian newspapers VG, Bergens Tidende and Aftenposten during 2013. The results show that there is a named researcher in about 12 % of the newspaper articles about school

  18. Redesign av Escola forlag sine skoleordbøker

    OpenAIRE

    Heggen, Inger Helene

    2007-01-01

    Rapporten består av en litteraturstudie (med begrepsavklaringer og en gjennomgang av ordboktypografiens historie – med hovedvekt på engelsk ordboktypografi), en analyse av ettspråklige ordbøker i dag (både norske og engelske), og en analyse av Escola Forlags ordbøker (bokmål og nynorsk utgave). Til slutt – en demononstrasjon av min resulterende redesign av ordbøkene (omslag og innmat). Her har det vært særlig viktig å tydeliggjøre oppslagsordene og oppslagsordenes underelementer s...

  19. Kartlegging av PCB i sedimenter fra Indre Sørfjord

    OpenAIRE

    Skei, J.; Klungsøyr, J.

    1990-01-01

    Som følge av forhøyede nivåer av PCB i fiskelever innerst i Sørfjorden er det gjennomført en sedimentundersøkelse for om mulig å finne kilden til PCB. Det ble ikke registrert høye nivåer av PCB i sedimentene. Høyeste konsentrasjoner ble målt i munningen av Eitrheimsvågen. Analyser av trafooljer brukt i Tyssedalsområdet viste spor av PCB. Statens forurensningstilsyn (SFT)

  20. Distributed Trust Management and Rogue AV Software

    Science.gov (United States)

    2010-06-10

    Integrate with QTM – Particularly important in federated systems (e.g., dynamically composable SOAs) • Investigate the use of reactive mechanisms – Global...of demonstrators surfaced on Capitol Hill in opposition to the Democrats’ health care legislation. MAGAZINE PREVIEW Making Health Care Better By...sale will be sent on saving green forests in Amazonia . Have more questions? You can contact us easy via Online Supoort. Green AV an award-winning

  1. Volatility in Equilibrium

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Sizova, Natalia; Tauchen, George

    Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast i......, and the dynamic cross-correlations of the volatility measures with the returns calculated from actual high-frequency intra-day data on the S&P 500 aggregate market and VIX volatility indexes....

  2. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  3. Konsum av risiko-matvarer - Beskrivelse av en undersøkelse som skal kartlegge konsum av matvarer med betydning for inntaket av miljøgifter

    Directory of Open Access Journals (Sweden)

    Helle Margrete Meltzer

    2009-11-01

    Full Text Available  SAMMENDRAGI perioden 1999-2001 vil det bli gjennomført tre kostholdsundersøkelser som til sammen skal kartlegge konsum avmatvarer med betydning for inntaket av miljøgifter i Norge, fortrinnsvis kadmium, kvikksølv, PCB og dioksiner.Disse giftene finnes hovedsakelig i krabbe, flatfisk, skjell, gjedde og abbor, lever eller nyre fra vilt og viltvoksendesopp. Fordi gjennomsnittskonsumet er lavt, spørres det ikke spesifikt om disse matvarene i landsdekkende kostholdsundersøkelsersom 'Norkost'. Hensikten med studien er å kunne gi en bedre beskrivelse av eksponeringsfordelingeni befolkningen med tanke på miljøgifter. Fordelingen er antakelig skjev, dvs. et stort antall personerventes å ha et lavt inntak og noen få personer ventes å ha et relativt høyt inntak av de undersøkte stoffene. Eventuelleukjente risikogrupper vil kunne avdekkes, og det er av stor interesse å undersøke hvor stor eksponeringen i deutsatte gruppene er.Del A av undersøkelsen er landsdekkende og omfatter en postal frekvensundersøkelse til 10 000 tilfeldig valgtepersoner mellom 18 og 79 år. Del B omfatter en postal frekvensundersøkelse til 6000 tilfeldig valgte personer i sekskommuner, der tre er kystkommuner og tre er innlandskommuner. Kommunene blir valgt ut fra kjennskap til godtilgang på de aktuelle matvarene. Vi antar at der tilgangen på matvarene er god, er konsumet høyere. Del C avundersøkelsen vil omfatte høykonsumenter av aktuelle matvarer, valgt fra del B av undersøkelsen. Dette vil være endybdestudie der analyser av miljøgifter i blod, hår og urin også skal inngå.Undersøkelsen er den første i sitt slag her til lands og vi kjenner ikke til at tilsvarende studier er gjort i andreland. Hensikten med artikkelen er å gi en beskrivelse av undersøkelsen i en tidlig fase av gjennomføringen.Meltzer HM, Bergsten C, Stene LC, Stigum H, Wiborg ML, Lund-Larsen K, Alexander J. Consumption ofcontaminated foods – Description of a dietary survey

  4. Microbial- and Thiosulfate-Mediated Dissolution of Mercury Sulfide Minerals and Transformation to Gaseous Mercury

    Directory of Open Access Journals (Sweden)

    Adiari eVázquez-Rodríguez

    2015-06-01

    Full Text Available Mercury (Hg is a toxic heavy metal that poses significant human and environmental health risks. Soils and sediments, where Hg can exist as the Hg sulfide mineral metacinnabar (β-HgS, represent major Hg reservoirs in aquatic environments. Metacinnabar has historically been considered a sink for Hg in all but severely acidic environments, and thus disregarded as a potential source of Hg back to aqueous or gaseous pools. Here, we conducted a combination of field and laboratory incubations to identify the potential for metacinnabar as a source of dissolved Hg within near neutral pH environments and the underpinning (abiotic mechanisms at play. We show that the abundant and widespread sulfur-oxidizing bacterium Thiobacillus extensively colonized metacinnabar chips incubated within aerobic, near neutral pH creek sediments. Laboratory incubations of axenic Thiobacillus cultures lead to the release of metacinnabar-hosted Hg(II and subsequent volatilization to Hg(0. This dissolution and volatilization was greatly enhanced in the presence of the sulfur intermediate, thiosulfate, which served a dual role by enhancing HgS dissolution and providing an additional metabolic substrate for Thiobacillus. These findings reveal a new coupled abiotic-biotic pathway for the transformation of metacinnabar-bound Hg(II to Hg(0, while expanding the sulfide substrates available for neutrophilic chemosynthetic bacteria to Hg-laden sulfides. They also point to mineral-hosted Hg as an underappreciated source of gaseous elemental Hg to the environment.

  5. An Empirical Application of a Two-Factor Model of Stochastic Volatility

    Czech Academy of Sciences Publication Activity Database

    Kuchyňka, Alexandr

    2008-01-01

    Roč. 17, č. 3 (2008), s. 243-253 ISSN 1210-0455 R&D Projects: GA ČR GA402/07/1113; GA MŠk(CZ) LC06075 Institutional research plan: CEZ:AV0Z10750506 Keywords : stochastic volatility * Kalman filter Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2008/E/kuchynka-an empirical application of a two-factor model of stochastic volatility.pdf

  6. Understanding Financial Market Volatility

    NARCIS (Netherlands)

    A. Opschoor (Anne)

    2014-01-01

    markdownabstract__Abstract__ Volatility has been one of the most active and successful areas of research in time series econometrics and economic forecasting in recent decades. Loosely speaking, volatility is defined as the average magnitude of fluctuations observed in some phenomenon over

  7. Improving Garch Volatility Forecasts

    NARCIS (Netherlands)

    Klaassen, F.J.G.M.

    1998-01-01

    Many researchers use GARCH models to generate volatility forecasts. We show, however, that such forecasts are too variable. To correct for this, we extend the GARCH model by distinguishing two regimes with different volatility levels. GARCH effects are allowed within each regime, so that our model

  8. Asymmetric Realized Volatility Risk

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); M. Scharth (Marcel)

    2014-01-01

    markdownabstract__Abstract__ In this paper we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized

  9. Selenium Uptake and Volatilization by Marine Algae

    Science.gov (United States)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  10. Design av oppbevaringsprodukt: Utvikling av et entrémøbel for IKEA

    OpenAIRE

    Bosvik, Helene

    2010-01-01

    Et av IKEAs store satsingsområder er oppbevaring. IKEA ønsker å nå ut til så mange mennesker som mulig med sine produkter. Deres visjon om å skape en bedre hverdag for de mange menneskene er et bevis på dette. Temaet for dette masterprosjektet har vært oppbevaring. En del av oppgaven har også vært å finne fokusområde innenfor temaet oppbevaring. Valget falt på entreen og utviklingen av entrémøbelet RÅDE. Oppgaven er gjort i samarbeid med IKEA Leangen i Trondheim. RÅDE er utviklet blant an...

  11. Barns opplevelse av postoperativ smerte og smertebehandling

    OpenAIRE

    Næss, Torgun

    2016-01-01

    Master i intensivsykepleie Bakgrunn: Postoperativ smerte hos barn er underbehandlet til tross for mye smerteforskning. Ulike studier har vist at barn opplever moderat til sterk smerte postoperativt. Ubehandlet smerte kan skape unødvendig lidelse for barn og øker risiko for komplikasjoner. Hensikt: Det finnes ingen forskning på norske barns opplevelse av postoperativ smerte og smertebehandling. Studiens hensikt er å få en større forståelse for hvordan barn opplever postoperativ smerte og sm...

  12. The volatility of HOL

    International Nuclear Information System (INIS)

    Wren, D.J.; Sanipelli, G.

    1985-01-01

    The volatility of HOI has been measured using a mass spectrometer to analyze the gas phase above an aqueous solution. The HOI in solution was generated continuously in a flow reactor that combined I/sup -/ and OCl/sup -/ solutions. The analysis has resulted in a lower limit of 6X10/sup 3/ mol . dm/sup -3/ . atm/sup -1/ for the equilibrium constant for the reaction HOI(g)/equilibrium/HOI(aq). This value is a factor 30 greater than the best previous estimate. This new limit for HOI volatility results in higher total iodine partition coefficients, particularly for solutions with pH>8. The upper limit for the equilibrium constant is consistent with essentially zero volatility for HOI. The effect of HOI volatility on total iodine volatility is briefly discussed as a function of solution chemistry and kinetics

  13. Implementering av BIM i bærekraftig oppgradering av bygninger: Mulighetsstudie for utføring av tilstandsanalyser med nettbrett

    OpenAIRE

    Vik, Vidar Samson

    2012-01-01

    Vi opplever i dag en økt hyppighet av klimakatastrofer som flom og tørke som følge av økt konsentrasjon av klimagasser i atmosfæren. Dette har ført til et behov for å redusere klimagassutslippene fra industrien på jorden. Byggebransjen, ofte kalt 40 % -bransjen, står for om lag 40 % av klimagassutslippene, og har dermed et stort potensial for reduksjon. BIM er en prosess som søker å redusere ressursbruken, og er dermed en bærekraftig prosess som har blitt tatt i bruk i stor skala i nybygg. Re...

  14. Surhetsvariasjoner som følge av nedtapping av et regulert vann.

    OpenAIRE

    Selmer-Olsen, A. R.

    1981-01-01

    Det har vært utført analyser og lagringsforsøk med prøver av tørrlagt bunnmateriale fra Trevatn tatt våren 1976. Prøver tatt ute i terrenget om høsten etter en lang tørr sommer viste stort sett samme bilde som prøvene fra våren etter lagring i laboratoriet under aerobe betingelser. Tabell 2 viser hvordan pH og SO4-S varierer med Iagringsbetingelsene. Oksydasjonsprosessene som slikt materiale blir utsatt for ved lufttilgang over et lengre tidsrom kan resultere i utvasking av meget sure forbind...

  15. Utveckling av examination av examensarbeten på kandidatnivå

    OpenAIRE

    Trofast, Tobias; Haugum, Dag; Lundberg, Jonas; Nygren, Victoria; Nyström, Tommie; Svensson, Gary; Thunborg, Maria; Törnqvist, Tomas

    2012-01-01

    Detta paper beskriver arbetet med att utveckla en modell för utveckling av examination av examensarbeten på kandidatnivå (UEX) vid Institutionen för Teknik och Naturvetenskap, Linköpings Universitet under läsåret 2010-2011. Modellen har utvecklats och testats vid utbildningsprogrammet Grafisk Design och Kommunikation (GDK), men med syfte att kunna appliceras även på andra kandidatprograms examensarbete. Det projektet prövat är om man kan höja kvaliteten på examensarbeten och effektiviteten i ...

  16. Upplevelser av "Employer Branding" : En kvalitativ fallstudie av anställda hos BA

    OpenAIRE

    Hermansson, Otto; Elisabeth, Mackenhauer

    2016-01-01

    Syftet med denna studie var att undersöka hur medarbetarna på BA (fiktivt namn) upplever organisationens interna Employer Branding-arbete samt att belysa de aspekter som eventuellt skiljer strategi mot upplevelse. Det gjordes ett målinriktat urval av organisation medan valet av deltagare var ett slumpmässigt urval vilket resulterade i åtta respondenter (n= 8). Studien var en kvalitativ fallstudie med ett psykologiskt angreppssätt och innehöll en ostrukturerad intervju som tillsammans m...

  17. Sulfidation/oxidation resistant alloys

    International Nuclear Information System (INIS)

    Smith, G.D.; Tassen, C.S.

    1989-01-01

    The patent describes a nickel-base, high chromium alloy. It is characterized by excellent resistance to sulfidation and oxidation at elevated temperatures as high as 2000 degrees F. (1093 degrees C.) and higher, a stress-rupture life of about 200 hours or more at a temperature at least as high as 1800 degrees F. (990:0083 degrees C.) and under a stress of 2000 psi, good tensile strength and good ductility both at room and elevated temperature. The alloy consists essentially of about 27 to 35% chromium, about 2.5 to 5% aluminum, about 2.5 to about 6% iron, 0.5 to 2.5% columbium, up to 0.1% carbon, up to 1% each of titanium and zirconium, up to 0.05% cerium, up to 0.05% yttrium, up to 1% silicon, up to 1% manganese, and the balance nickel

  18. AVS user's guide on the basis of practice

    International Nuclear Information System (INIS)

    Masuko, Kenji; Kato, Katsumi; Kume, Etsuo; Fujii, Minoru.

    1997-07-01

    The special guides for the use of visualization software AVS have been developed at Japan Atomic Energy Research Institute (JAERI). The purpose of these guides is to help the AVS users understand easily the use of the one, due to the fact that it is so difficult for beginners to understand the original manuals. In this report, 'Transportation Evacuation Simulation' is taken up as an object of visualization, and the procedure of visualization and images recording by using the AVS are described. By using the AVS according to this report, a series of the procedure which are necessary for use of the AVS can be acquired. (author)

  19. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......: (1) impact of low viscous droplets of iron sulfide; and (2) sulfur diffusion. Previous research on the influence of pyrite on slagging focused on the decomposition of pyrite into pyrrhotite and especially on the oxidation stage of this product during impact on the heat transfer surfaces...

  20. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  1. Interior Volatile Reservoirs in Mercury

    Science.gov (United States)

    Anzures, B. A.; Parman, S. W.; Milliken, R. E.; Head, J. W.

    2018-05-01

    More measurements of 1) surface volatiles, and 2) pyroclastic deposits paired with experimental volatile analyses in silicate minerals can constrain conditions of melting and subsequent eruption on Mercury.

  2. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2015-01-01

    Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field...... as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments....

  3. Implementeringsforskning: vitenskap for forbedring av praksis

    Directory of Open Access Journals (Sweden)

    Signe Flottorp

    2013-11-01

    Full Text Available Medisinsk forskning har ført til store framskritt de siste tiårene. Det er investert mye mer ressurser på basalforskning og klinisk forskning enn på å utvikle og evaluere metoder for å sikre at pasientene får nytte av forskningen. Formålet med implementeringsforskning er å redusere gapet mellom forskning og praksis, ved å utvikle og evaluere tiltak som kan sikre at behandlingen som pasientene mottar er kunnskapsbasert, at den er omsorgsfull og av god kvalitet.I denne artikkelen gjør vi rede for hva implementering og implementeringsforskning er. Vi belyser historikken til denne unge vitenskapen, og illustrerer mangfoldet i de faglige tilnærmingene og begrepene som brukes om det å få forskning brukt i praksis. Det finnes en rekke teorier om endring av atferd, både på individnivå og på organisatorisk nivå. Teoriene er imidlertid i liten grad testet empirisk, særlig når det gjelder å endre atferd i helsetjenesten.Systematiske oversikter over metodisk gode studier er den beste kilden til informasjon om effekt av implementeringstiltak. The Cochrane Effective Practice and Organisation of Care Group (EPOC er en viktig kilde for slike oversikter. De systematiske oversiktene som er utarbeidet på dette feltet viser at passive dissemineringstiltak har begrenset effekt, mens mer aktive tiltak kan ha liten til moderat effekt. Det er ofte betydelig variasjon i effekt på tvers av studiene. Det er derfor viktig å få bedre kunnskap om hvilke faktorer som kan forklare slike forskjeller i effekt.Vi gir eksempler på norske implementeringsstudier, og refererer bidrag fra forskere ved Kunnskapssenteret. Implementeringsforskningen kan, hvis den lykkes, sikre pasientene bedre behandling.Flottorp S, Aakhus E. Implementation research: science for improving practice. Nor J Epidemiol 201 3; 23 (2: 187-196.ENGLISH SUMMARY Medical research has led to major advances in recent decades. More resources have been invested in basic and clinical research

  4. Pluto's Volatile Transport

    Science.gov (United States)

    Young, Leslie

    2012-10-01

    Pluto's varying subsolar latitude and heliocentric distance leads to large variations in the surface volatile distribution and surface pressure. I present results of new volatile transport models (Young 2012a, b). The models include insolation, thermal emission, subsurface conduction, heating of a volatile slab, internal heat flux, latent heat of sublimation, and strict global mass balance. Numeric advances include initial conditions that allow for rapid convergence, efficient computation with matrix arithmetic, and stable Crank-Nicholson timesteps for both bare and volatile-covered areas. Runs of the model show six distinct seasons on Pluto. (1) As Pluto approaches perihelion, the volatiles on the old winter pole (the Rotational North Pole, RNP) becomes more directly illuminated , and the pressure and albedo rise rapidly. (2) When a new ice cap forms on the Rotational South Pole, RSP, volatiles are exchanged between poles. The pressure and albedo change more slowly. (3) When all volatiles have sublimed from the RNP, the albedo and pressure drop rapidly. (4-6) A similar pattern is repeated near aphelion with a reversal of the roles and the poles. I will compare results with earlier Pluto models of Hansen and Paige (1996), show the dependence on parameters such as substrate inertia, and make predictions for the New Horizons flyby of Pluto in 2015. This work was supported, in part, by funding from NASA Planetary Atmospheres Grant NNG06GF32G and the Spitzer project (JPL research support Agreement 1368573). Hansen, C. J. and D. A. Paige 1996. Seasonal Nitrogen Cycles on Pluto. Icarus 120, 247-265. Young, L. A. 2012a. Volatile transport on inhomogeneous surfaces: I - Analytic expressions, with application to Pluto’s day. Icarus, in press Young, L. A. 2012b. Volatile transport on inhomogeneous surfaces: II. Numerical calculations, with application to Pluto's season. In preparation.

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

    Science.gov (United States)

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

    2008-10-08

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

  6. Bruk av amniocenteser og chorionbiopsier i Norge

    Directory of Open Access Journals (Sweden)

    Guttorm Haugen

    2009-10-01

    Full Text Available  SAMMENDRAGInvasiv prenatal diagnostikk i form av amniocentese (fostervannsprøve og chorionbiopsi (morkakeprøveutføres i ca. 2% av alle svangerskap i Norge per år. Dette er betydelig færre undersøkelser ennhva som utføres i de andre nordiske land. De fleste får utført amniocentese pga. høy maternell alder(aldersindikasjon som her i landet er ≥ 38 år ved fødselstermin. Chorionbiopsi er forbeholdt kvinnermed kjente arvelige lidelser i familien, dvs. kvinner med høy risiko for å få et affisert foster. De undersøkelsersom foreligger over svangerskapsutfall samt forekomst av komplikasjoner etter amniocenteseog chorionbiopsi er hovedsakelig utført i andre land på kvinner med generelt lavere risiko ( ≥ 35 år ennfor dem som får utført invasiv prenatal diagnostikk i Norge. Pga. vår restriktive praksis kan ikke disseresultatene uten videre overføres til Norge. Vi mangler eksakte data over svangerskapsutfall og evt.komplikasjoner etter disse undersøkelsene i en norsk populasjon.Haugen G, van der Hagen CB. The use of amniocentesis and chorionic villus sampling in Norway.Nor J Epidemiol ENGLISH SUMMARYAmniocentesis or chorionic villus sampling are performed in about 2% of all pregnancies in Norwaywhich is far less than in the other Nordic countries. Most of the amniocenteses are performed due toadvanced maternal age. In Norway this is defined as maternal age ≥ 38 years at term. Couples withknown chromosomal aberrations or genetic diseases in their families, i.e. women at a high risk of havingan affected fetus, are offered chorionic villus sampling. Earlier studies on complications and pregnancyoutcome following amniocentesis or chorionic villus sampling have been performed in other countriesmainly on women at a lower risk ( ≥ 35 years than for the women having such tests in Norway. We donot have data on pregnancy outcome and possible complications following amniocentesis and chorionicvillus sampling in a Norwegian

  7. Crossett Hydrogen Sulfide Air Sampling Report

    Science.gov (United States)

    This report summarizes the results of the EPA’s hydrogen sulfide air monitoring conducted along Georgia Pacific’s wastewater treatment system and in surrounding Crossett, AR, neighborhoods in 2017.

  8. Analys av nickel med ICP-MS

    OpenAIRE

    Wallman, Karin; Löfgren, Stefan; Sonesten, Lars; Demandt, Christian

    2009-01-01

    Vid en granskning av nickelhalter för perioden 1985-2007 upptäcktes ett nivåskifte i tidsserierna på flera stationer mellan 2001 och 2002. Skiftet visade sig bero på att prover innan 2002 inte korrigerades för kalciuminterferens, medan prover under åren 2002-2007 korrigerades. Syftet med denna rapport är att utreda om resultaten före 2002 i efterhand kan korrigeras för kalciuminterferensen. Från 2002 finns ett antal prover (N=347) med resultat som både är kalciumkorrigerade och som inte är de...

  9. Mathematical Modelling of Supercritical CO2 Extraction of Volatile Oils from Aromatic Plants

    Czech Academy of Sciences Publication Activity Database

    Grosso, C.; Coelho, J.P.; Pessoa, F.L.P.; Fareleira, J.M.N.A.; Barroso, J.G.; Urieta, J.S.; Palavra, A.F.; Sovová, Helena

    2010-01-01

    Roč. 65, č. 11 (2010), s. 3579-3590 ISSN 0009-2509 Institutional research plan: CEZ:AV0Z40720504 Keywords : supercritical fluid extraction * modelling * volatile oils Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.379, year: 2010

  10. Optimizing headspace sampling temperature and time for analysis of volatile oxidation products in fish oil

    DEFF Research Database (Denmark)

    Rørbæk, Karen; Jensen, Benny

    1997-01-01

    Headspace-gas chromatography (HS-GC), based on adsorption to Tenax GR(R), thermal desorption and GC, has been used for analysis of volatiles in fish oil. To optimize sam sampling conditions, the effect of heating the fish oil at various temperatures and times was evaluated from anisidine values (AV...

  11. Determining the vapour pressures of plant volatiles from gas chromatographic retention data

    Czech Academy of Sciences Publication Activity Database

    Hoskovec, Michal; Grygarová, D.; Cvačka, Josef; Streinz, Ludvík; Zima, J.; Verevkin, S. P.; Koutek, Bohumír

    2005-01-01

    Roč. 1083, - (2005), s. 161-172 ISSN 0021-9673 Institutional research plan: CEZ:AV0Z4055905 Keywords : vapour pressure * thermodinamic parameters * plant volatiles Subject RIV: CC - Organic Chemistry Impact factor: 3.096, year: 2005

  12. Chloride – a precursor in the formation of volatile organochlorines by forest plants?

    Czech Academy of Sciences Publication Activity Database

    Laturnus, F.; Matucha, Miroslav

    2008-01-01

    Roč. 99, č. 1 (2008), s. 119-125 ISSN 0265-931X R&D Projects: GA ČR GA526/05/0636 Institutional research plan: CEZ:AV0Z50380511 Keywords : 36Chloride * Volatile Organochlorines * VOCl Subject RIV: DF - Soil Science Impact factor: 1.114, year: 2008

  13. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  14. Non-volatile memories

    CERN Document Server

    Lacaze, Pierre-Camille

    2014-01-01

    Written for scientists, researchers, and engineers, Non-volatile Memories describes the recent research and implementations in relation to the design of a new generation of non-volatile electronic memories. The objective is to replace existing memories (DRAM, SRAM, EEPROM, Flash, etc.) with a universal memory model likely to reach better performances than the current types of memory: extremely high commutation speeds, high implantation densities and retention time of information of about ten years.

  15. Ammonia volatilization losses from paddy fields under controlled irrigation with different drainage treatments.

    Science.gov (United States)

    He, Yupu; Yang, Shihong; Xu, Junzeng; Wang, Yijiang; Peng, Shizhang

    2014-01-01

    The effect of controlled drainage (CD) on ammonia volatilization (AV) losses from paddy fields under controlled irrigation (CI) was investigated by managing water table control levels using a lysimeter. Three drainage treatments were implemented, namely, controlled water table depth 1 (CWT1), controlled water table depth 2 (CWT2), and controlled water table depth 3 (CWT3). As the water table control levels increased, irrigation water volumes in the CI paddy fields decreased. AV losses from paddy fields reduced due to the increases in water table control levels. Seasonal AV losses from CWT1, CWT2, and CWT3 were 59.8, 56.7, and 53.0 kg N ha(-1), respectively. AV losses from CWT3 were 13.1% and 8.4% lower than those from CWT1 and CWT2, respectively. A significant difference in the seasonal AV losses was confirmed between CWT1 and CWT3. Less weekly AV losses followed by TF and PF were also observed as the water table control levels increased. The application of CD by increasing water table control levels to a suitable level could effectively reduce irrigation water volumes and AV losses from CI paddy fields. The combination of CI and CD may be a feasible water management method of reducing AV losses from paddy fields.

  16. American options under stochastic volatility

    NARCIS (Netherlands)

    Chockalingam, A.; Muthuraman, K.

    2011-01-01

    The problem of pricing an American option written on an underlying asset with constant price volatility has been studied extensively in literature. Real-world data, however, demonstrate that volatility is not constant, and stochastic volatility models are used to account for dynamic volatility

  17. An Overview of the HomePlug AV2 Technology

    Directory of Open Access Journals (Sweden)

    Larry Yonge

    2013-01-01

    Full Text Available HomePlug AV2 is the solution identified by the HomePlug Alliance to achieve the improved data rate performance required by the new generation of multimedia applications without the need to install extra wires. Developed by industry-leading participants in the HomePlug AV Technical Working Group, the HomePlug AV2 technology provides Gigabit-class connection speeds over the existing AC wires within home. It is designed to meet the market demands for the full set of future in-home networking connectivity. Moreover, HomePlug AV2 guarantees backward interoperability with other HomePlug systems. In this paper, the HomePlug AV2 system architecture is introduced and the technical details of the key features at both the PHY and MAC layers are described. The HomePlug AV2 performance is assessed, through simulations reproducing real home scenarios.

  18. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  19. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  20. Avveckling av aktiebolag : Case: Likvidation av Företag X Ab

    OpenAIRE

    Kallio, Josefine

    2015-01-01

    Syftet med detta lärdomsprov är att ta reda på hur man idag i Finland kan avveckla ett aktiebolag. De fyra olika avvecklingssätten likvidation, konkurs, fusion och delning av aktiebolag är de sätt som används i Finland för att upplösa aktiebolag. I lärdomsprovet har fokus mest lagts på likvidation av aktiebolag. Lärdomsprovet ger svar på bl.a. hur en likvidation går till, vem som kan vara likvidator, vad som är skillnaden mellan en frivillig likvidation och en tvångsmässig likvidation m.m. Lä...

  1. Når kontakter betyr alt : En studie av bruken av nettverksmediet LinkedIn

    OpenAIRE

    Blaalid, Maren Hyvang

    2012-01-01

    LinkedIn er et av de mest populære sosiale mediene i Norge og tiltrekker seg stadig flere medlemmer. I denne masteroppgaven studerer jeg bruken av LinkedIn for å undersøke hva som er det særegne ved dette nettverksmediet. Jeg har utført en spørreundersøkelse blant 280 brukere for å få innsikt i hvem de er, hvorfor de bruker LinkedIn og hvordan de gjør det. Funnene fra analysen viser at brukerne kjennetegnes ved at de er selvstendige og formålsrasjonelle, som bruker LinkedIn strategisk for å n...

  2. Oil and stock market volatility: A multivariate stochastic volatility perspective

    International Nuclear Information System (INIS)

    Vo, Minh

    2011-01-01

    This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility structure in an attempt to extract information intertwined in both markets for risk prediction. It offers four major findings. First, the stock and oil futures prices are inter-related. Their correlation follows a time-varying dynamic process and tends to increase when the markets are more volatile. Second, conditioned on the past information, the volatility in each market is very persistent, i.e., it varies in a predictable manner. Third, there is inter-market dependence in volatility. Innovations that hit either market can affect the volatility in the other market. In other words, conditioned on the persistence and the past volatility in their respective markets, the past volatility of the stock (oil futures) market also has predictive power over the future volatility of the oil futures (stock) market. Finally, the model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry. - Research Highlights: → This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility model. → The correlation between the two markets follows a time-varying dynamic process which tends to increase when the markets are more volatile. → The volatility in each market is very persistent. → Innovations that hit either market can affect the volatility in the other market. → The model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry.

  3. Hydrogen sulfide-powered solid oxide fuel cells

    Science.gov (United States)

    Liu, Man

    2004-12-01

    The potential utilization of hydrogen sulfide as fuel in solid oxide fuel cells has been investigated using an oxide-ion conducting YSZ electrolyte and different kinds of anode catalysts at operating temperatures in the range of 700--900°C and at atmospheric pressure. This technology offers an economically attractive alternative to present methods for removing toxic and corrosive H2S gas from sour gas streams and a promising approach for cogenerating electrical energy and useful chemicals. The primary objective of the present research was to find active and stable anode materials. Fuel cell experimental results showed that platinum was a good electrocatalyst for the conversion of H2S, but the Pt/YSZ interface was physically unstable due to the reversible formation and decomposition of PtS in H 2S streams at elevated temperatures. Moreover, instability of the Pt/YSZ interface was accelerated significantly by electrochemical reactions, and ultimately led to the detachment of the Pt anode from the electrolyte. It has been shown that an interlayer of TiO2 stabilized the Pt anode on YSZ electrolyte, thereby prolonging cell lifetime. However, the current output for a fuel cell using Pt/TiO2 as anode was not improved compared to using Pt alone. It was therefore necessary to investigate novel anode systems for H 2S-air SOFCs. New anode catalysts comprising composite metal sulfides were developed. These catalysts exhibited good electrical conductivity and better catalytic activity than Pt. In contrast to MoS2 alone, composite catalysts (M-Mo-S, M = Fe, Co, Ni) were not volatile and had superior stability. However, when used for extended periods of time, detachment of Pt current collecting film from anodes comprising metal sulfides alone resulted in a large increase in contact resistance and reduction in cell performance. Consequently, a systematic investigation was conducted to identify alternative electronic conductors for use with M-Mo-S catalysts. Anode catalysts

  4. Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase*

    Science.gov (United States)

    Mishanina, Tatiana V.; Yadav, Pramod K.; Ballou, David P.; Banerjee, Ruma

    2015-01-01

    The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be −123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. PMID:26318450

  5. Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase.

    Science.gov (United States)

    Mishanina, Tatiana V; Yadav, Pramod K; Ballou, David P; Banerjee, Ruma

    2015-10-09

    The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be -123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Experimental simulations of sulfide formation in the solar nebula.

    Science.gov (United States)

    Lauretta, D S; Lodders, K; Fegley, B

    1997-07-18

    Sulfurization of meteoritic metal in H2S-H2 gas produced three different sulfides: monosulfide solid solution [(Fe,Ni)1-xS], pentlandite [(Fe,Ni)9-xS8], and a phosphorus-rich sulfide. The composition of the remnant metal was unchanged. These results are contrary to theoretical predictions that sulfide formation in the solar nebula produced troilite (FeS) and enriched the remaining metal in nickel. The experimental sulfides are chemically and morphologically similar to sulfide grains in the matrix of the Alais (class CI) carbonaceous chondrite, suggesting that these meteoritic sulfides may be condensates from the solar nebula.

  7. Analysis of volatile metabolites in biological fluids as indicators of prodromal disease condition

    Science.gov (United States)

    Zlatkis, A.

    1982-01-01

    The volatile profile cannot be defined as a single class of substances, rather it is a broad spectrum of materials of different polarities characterized by having a boiling-point in the low to medium range (up to approximately 300 C) and the fact that the compounds are suitable for gas chromatography without derivatization. The organic volatile profiles are very complex mixtures of metabolic byproducts, intermediates, and terminal products of enzymatic degradations composed mainly of alcohols, ketones, aldehydes, pyrazines, sulfides, isothiocyanates, pyrroles, and furans. The concentration of organic volatiles in biological fluids covers a wide range with many important components present at trace levels. The complexity of the organic volatile fraction requires the use of capillary columns for their separation.

  8. Pollen transmission of asparagus virus 2 (AV-2) may facilitate mixed infection by two AV-2 isolates in asparagus plants.

    Science.gov (United States)

    Kawamura, Ryusuke; Shimura, Hanako; Mochizuki, Tomofumi; Ohki, Satoshi T; Masuta, Chikara

    2014-09-01

    Asparagus virus 2 (AV-2) is a member of the genus Ilarvirus and thought to induce the asparagus decline syndrome. AV-2 is known to be transmitted by seed, and the possibility of pollen transmission was proposed 25 years ago but not verified. In AV-2 sequence analyses, we have unexpectedly found mixed infection by two distinct AV-2 isolates in two asparagus plants. Because mixed infections by two related viruses are normally prevented by cross protection, we suspected that pollen transmission of AV-2 is involved in mixed infection. Immunohistochemical analyses and in situ hybridization using AV-2-infected tobacco plants revealed that AV-2 was localized in the meristem and associated with pollen grains. To experimentally produce a mixed infection via pollen transmission, two Nicotiana benthamiana plants that were infected with each of two AV-2 isolates were crossed. Derived cleaved-amplified polymorphic sequence analysis identified each AV-2 isolate in the progeny seedlings, suggesting that pollen transmission could indeed result in a mixed infection, at least in N. benthamiana.

  9. Spa-typing av stammer av Staphylococcus aureus fra blodkulturer analysert ved UNN Tromsø 2007-2008

    OpenAIRE

    Midtgard, Anette

    2011-01-01

    Bakgrunn: Staphylococcus aureus er et av de vanligste patogenene som kan skape sykdom hos mennesket. Mange av oss er bærere av bakterien i nese eller hals, og det er vist at persisterende bærere har høyere risiko for å utvikle S. aureus-infeksjoner enn andre. De fleste S. aureus-infeksjonene blant bærere er forårsaket av pasientens egen bakteriestamme. Materiale og metode: 140 blodkulturisolater fra pasienter med S. aureus bakteriemi analysert ved Avdeling for mikrobiologi og smitte...

  10. Effekt av melkesyrebakteriers metabolisme på utviklingen av Escherichia coli O157:H7 i melk

    OpenAIRE

    Westblad, Anne Margrethe

    2010-01-01

    Dagens regelverk sier at all melk som omsettes skal være varmebehandlet, men åpner samtidig for salg av melkeprodukter basert på upasteurisert melk, forutsatt overholdelse av visse krav. Dermed kan småskalavirksomheter framstille melkeprodukter av upasteurisert melk hvis de skulle ønske det. Et slikt ønske er ofte begrunnet i tradisjoner og praktiske forhold. I tillegg er det flere som påstår at råmelk er sunnere enn pasteurisert melk og at råmelkas mikroflora hemmer vekst av uønskede bakteri...

  11. Sulfide Precipitation in Wastewater at Short Timescales

    DEFF Research Database (Denmark)

    Kiilerich, Bruno; van de Ven, Wilbert; Nielsen, Asbjørn Haaning

    2017-01-01

    Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows that this i......Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows...... that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio...

  12. Volatile liquid storage system

    International Nuclear Information System (INIS)

    Laverman, R.J.; Winters, P.J.; Rinehart, J.K.

    1992-01-01

    This patent describes a method of collecting and abating emission from a volatile liquid in an above ground storage tank. It comprises the liquid storage tank having a bottom, a vertical cylindrical circular wall having a lower edge portion joined to the bottom, and an external fixed roof, the tank having an internal floating roof floating on a volatile liquid stored in the tank, and air vent means in the tank in communication with a vapor space in the tank constituting at least the space above the floating roof when the floating roof floats on a predetermined maximum volume of volatile liquid in the tank; permitting ambient air; pumping emission laden air from the tank vapor space above the floating roof; and by means of the emissions abatement apparatus eliminating most of the emission from the emissions laden air with formation of a gaseous effluent and then discharging the resulting gaseous effluent to the atmosphere

  13. Understanding Interest Rate Volatility

    DEFF Research Database (Denmark)

    Volker, Desi

    This thesis is the result of my Ph.D. studies at the Department of Finance of the Copenhagen Business School. It consists of three essays covering topics related to the term structure of interest rates, monetary policy and interest rate volatility. The rst essay, \\Monetary Policy Uncertainty...... and Interest Rates", examines the role of monetary policy uncertainty on the term structure of interest rates. The second essay, \\A Regime-Switching A ne Term Structure Model with Stochastic Volatility" (co-authored with Sebastian Fux), investigates the ability of the class of regime switching models...... with and without stochastic volatility to capture the main stylized features of U.S. interest rates. The third essay, \\Variance Risk Premia in the Interest Rate Swap Market", investigates the time-series and cross-sectional properties of the compensation demanded for holding interest rate variance risk. The essays...

  14. EST Table: AV398539 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV398539 NV021929 11/12/09 GO hit GO:0005622(intracellular)|GO:0008270(zinc ion bin...0769|gb|EEZ97216.1| hypothetical protein TcasGA2_TC011009 [Tribolium castaneum] AV398539 NV02 ...

  15. AVS-1357 inhibits melanogenesis via prolonged ERK activation.

    Science.gov (United States)

    Kim, Dong-Seok; Lee, Hyun-Kyung; Park, Seo-Hyoung; Chae, Chong Hak; Park, Kyoung-Chan

    2009-08-01

    In this study, we demonstrated that a derivative of imidazole, AVS-1357, is a novel skin-whitening compound. AVS-1357 was found to significantly inhibit melanin production in a dose-dependent manner; however, it did not directly inhibit tyrosinase. Furthermore, we found that AVS-1357 induced prolonged activation of extracellular signal-regulated kinase (ERK) and Akt, while it downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase. It has been reported that the activation of ERK and/or Akt is involved in melanogenesis. Therefore, we examined the effects of AVS-1357 on melanogenesis in the absence or presence of PD98059 (a specific inhibitor of the ERK pathway) and/or LY294002 (a specific inhibitor of the Akt pathway). PD98059 dramatically increased melanogenesis, whereas LY294002 had no effect. Furthermore, PD98059 attenuated AVS-1357 induced ERK activation, as well as the downregulation of MITF and tyrosinase. These findings suggest that the effects of AVS-1357 occur via downregulation of MITF and tyrosinase, which is caused by AVS-1357-induced prolonged ERK activation. Taken together, our results indicate that AVS-1357 has the potential as a new skin whitening agent.

  16. Functional consortium for denitrifying sulfide removal process.

    Science.gov (United States)

    Chen, Chuan; Ren, Nanqi; Wang, Aijie; Liu, Lihong; Lee, Duu-Jong

    2010-03-01

    Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10(-2) to 10(-6) dilutions to elucidate the correlation between the composition of the microbial community and the DSR performance. In the original suspension and in 10(-2) dilution, the strains Stenotrophomonas sp., Thauera sp., and Azoarcus sp. are the heterotrophic denitrifiers and the strains Paracoccus sp. and Pseudomonas sp. are the sulfide-oxidizing denitrifers. The 10(-4) dilution is identified as the functional consortium for the present DSR system, which comprises two functional strains, Stenotrophomonas sp. strain Paracoccus sp. At 10(-6) dilution, all DSR performance was lost. The functions of the constituent cells in the DSR granules were discussed based on data obtained using the dilution-to-extinction approach.

  17. Pricing Volatility of Stock Returns with Volatile and Persistent Components

    DEFF Research Database (Denmark)

    Zhu, Jie

    2009-01-01

    This paper introduces a two-component volatility model based on first moments of both components to describe the dynamics of speculative return volatility. The two components capture the volatile and the persistent part of volatility, respectively. The model is applied to 10 Asia-Pacific stock ma...... markets. A positive or risk-premium effect exists between the return and the volatile component, yet the persistent component is not significantly priced for the return dynamic process....... markets. Their in-mean effects on returns are tested. The empirical results show that the persistent component is much more important for the volatility dynamic process than is the volatile component. However, the volatile component is found to be a significant pricing factor of asset returns for most...

  18. Pricing Volatility of Stock Returns with Volatile and Persistent Components

    DEFF Research Database (Denmark)

    Zhu, Jie

    In this paper a two-component volatility model based on the component's first moment is introduced to describe the dynamic of speculative return volatility. The two components capture the volatile and persistent part of volatility respectively. Then the model is applied to 10 Asia-Pacific stock m......, a positive or risk-premium effect exists between return and the volatile component, yet the persistent component is not significantly priced for return dynamic process....... markets. Their in-mean effects on return are also tested. The empirical results show that the persistent component accounts much more for volatility dynamic process than the volatile component. However the volatile component is found to be a significant pricing factor of asset returns for most markets...

  19. Production and Preservation of Sulfide Layering in Mercury's Magma Ocean

    Science.gov (United States)

    Boukare, C.-E.; Parman, S. W.; Parmentier, E. M.; Anzures, B. A.

    2018-05-01

    Mercury's magma ocean (MMO) would have been sulfur-rich. At some point during MMO solidification, it likely became sulfide saturated. Here we present physiochemical models exploring sulfide layer formation and stability.

  20. Mineralogical Mapping of Quadrangle Av-2 (belicia) and Av-3 (caparronia) on 4 Vesta.

    Science.gov (United States)

    Stephan, K.; Frigeri, A.; Barucci, M. A.; Sunshine, J.; Jaumann, R.; Palomba, E.; Blewett, D. T.; Yingst, A.; Marchi, S.; De Sanctis, C. M.; Matz, K.-D.; Roatsch, Th.; Preusker, F.; Le Corre, L.; Reddy, V.; Russell, C. T.; Raymond, C. A.

    2012-04-01

    Since the arrival of the Dawn spacecraft at 4 Vesta on July 16, 2011 the Visible and InfraRed Imaging Spectrometer (VIR) has acquired hyperspectral images of Vesta's surface, which enable to characterize Vesta's mineralogical composition in the wavelength range from 0.25 to 5.1µm. As part of the analysis of Vesta's surface composition the science team is preparing a series of 15 quadrangle maps showing the results derived from the spectroscopic analysis of the VIR and FC color data. We present preliminary results of the spectroscopic analysis achieved for the quadrangles Av-2 (Belicia) and Av-3 (Caparronia), which show Vesta's surface between 21°N - 66° N°, 0° - 90°E and 90° - 180° E, respectively. These results are based on the analysis of the combination of the visible albedo, spectral parameters including the position, depth of the pyroxene absorptions, as well as color ratio composites using the VIR channels centering at 749nm/438nm (Red), 749nm/917nm (Green) and 438nm/749nm (Blue). Vesta's rotation axis, however, is tilted ~29° with respect to its orbital plane. Since Dawn arrived during northern winter, portions of Vesta north of ~45° N are dominated by extended shadows or have not yet been imaged due to permanent night. Thus, limited FC color or VIR hyperspectral data have been available for the quadrangles Av-2 and Av-3. The illuminated parts are dominated by a heavily-cratered northern terrain with ancient troughs and grooves and named after the prominent relatively large impact craters Belicia (~37°N/48°E) and Caparronia (~36°N/167°E). Numerous impact craters of different size, morphology, and state of surface degradation are apparent. Most spectral variations are strongly affected by the extreme illumination conditions, making the analysis of albedo variations and spectral signatures rather difficult. Their interpretation thus remains. Nevertheless, VIR spectra show clear evidence of Vesta's surface composition similar to those of HED

  1. Cofactor requirement of HpyAV restriction endonuclease.

    Directory of Open Access Journals (Sweden)

    Siu-Hong Chan

    Full Text Available BACKGROUND: Helicobacter pylori is the etiologic agent of common gastritis and a risk factor for gastric cancer. It is also one of the richest sources of Type II restriction-modification (R-M systems in microorganisms. PRINCIPAL FINDINGS: We have cloned, expressed and purified a new restriction endonuclease HpyAV from H. pylori strain 26695. We determined the HpyAV DNA recognition sequence and cleavage site as CCTTC 6/5. In addition, we found that HpyAV has a unique metal ion requirement: its cleavage activity is higher with transition metal ions than in Mg(++. The special metal ion requirement of HpyAV can be attributed to the presence of a HNH catalytic site similar to ColE9 nuclease instead of the canonical PD-X-D/EXK catalytic site found in many other REases. Site-directed mutagenesis was carried out to verify the catalytic residues of HpyAV. Mutation of the conserved metal-binding Asn311 and His320 to alanine eliminated cleavage activity. HpyAV variant H295A displayed approximately 1% of wt activity. CONCLUSIONS/SIGNIFICANCE: Some HNH-type endonucleases have unique metal ion cofactor requirement for optimal activities. Homology modeling and site-directed mutagenesis confirmed that HpyAV is a member of the HNH nuclease family. The identification of catalytic residues in HpyAV paved the way for further engineering of the metal binding site. A survey of sequenced microbial genomes uncovered 10 putative R-M systems that show high sequence similarity to the HpyAV system, suggesting lateral transfer of a prototypic HpyAV-like R-M system among these microorganisms.

  2. The role of sulfides in the fractionation of highly siderophile and chalcophile elements during the formation of martian shergottite meteorites

    Science.gov (United States)

    Baumgartner, Raphael J.; Fiorentini, Marco L.; Lorand, Jean-Pierre; Baratoux, David; Zaccarini, Federica; Ferrière, Ludovic; Prašek, Marko K.; Sener, Kerim

    2017-08-01

    The shergottite meteorites are ultramafic to mafic igneous rocks whose parental magmas formed from partial melting of the martian mantle. This study reports in-situ laser ablation inductively coupled plasma mass spectrometry analyses for siderophile and chalcophile major and trace elements (i.e., Co, Ni, Cu, As, Se, Ag, Sb, Te, Pb, Bi, and the highly siderophile platinum-group elements, PGE: Os, Ir, Ru, Rh, Pt and Pd) of magmatic Fe-Ni-Cu sulfide assemblages from four shergottite meteorites. They include three geochemically similar incompatible trace element- (ITE-) depleted olivine-phyric shergottites (Yamato-980459, Dar al Gani 476 and Dhofar 019) that presumably formed from similar mantle and magma sources, and one distinctively ITE-enriched basaltic shergottite (Zagami). The sulfides in the shergottites have been variably modified by alteration on Earth and Mars, as well as by impact shock-shock related melting/volatilization during meteorite ejection. However, they inherit and retain their magmatic PGE signatures. The CI chondrite-normalized PGE concentration patterns of sulfides reproduce the whole-rock signatures determined in previous studies. These similarities indicate that sulfides exerted a major control on the PGE during shergottite petrogenesis. However, depletions of Pt (and Ir) in sulfide relative to the other PGE suggest that additional phases such discrete Pt-Fe-Ir alloys have played an important role in the concentration of these elements. These alloys are expected to have enhanced stability in reduced and FeO-rich shergottite magmas, and could be a common feature in martian igneous systems. A Pt-rich PGM was found to occur in a sulfide assemblage in Dhofar 019. However, its origin may be related to impact shock-related sulfide melting and volatilisation during meteorite ejection. In the ITE-depleted olivine-phyric shergottites, positive relationships exist between petrogenetic indicators (e.g., whole-rock Mg-number) and most moderately to

  3. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  4. Girdler-sulfide process physical properties

    International Nuclear Information System (INIS)

    Neuburg, H.J.; Atherley, J.F.; Walker, L.G.

    1977-05-01

    Physical properties of pure hydrogen sulfide and of gaseous and liquid solutions of the H 2 S-H 2 O system have been formulated. Tables for forty-nine different properties in the pressure and temperature range of interest to the Girdler-Sulfide (GS) process for heavy water production are given. All properties are presented in SI units. A computer program capable of calculating properties of the pure components as well as gaseous mixtures and liquid solutions at saturated and non-saturated conditions is included. (author)

  5. Modellering av urbane pluviale flommer ved bruk av værradar

    OpenAIRE

    Kjølseth, Tora Marie Hveem; Vatne, Ingrid

    2017-01-01

    Ekstreme nedbørhendelser med påfølgende pluviale flommer forårsaker store skader på infrastruktur og bebyggelse. Skadene fører til betydelige samfunnskostnader, og problemet er økende. Avrenningsmodeller kan benyttes for å simulere flomforløpet til en nedbørhendelse, og er et mye brukt verktøy i planlegging, prosjektering, dimensjonering og drift av overvann-systemer. Som inngangsdata i avrenningsmodeller er det vanlig å bruke konstruert nedbør, der det tas utgangspunkt i målinger og statisti...

  6. Transport og akkumulering av jern i profiler av et dyrket myrareal

    OpenAIRE

    Ødelien, M.; Selmer-Olsen, A. R.; Lie, Ole

    1980-01-01

    En mindre del av et stort dyrket myrareal på eiendommen Vivang, Våler i Solør, har uvanlig jernrik torv. Her har havre hatt god vegetativ vekst, men meget dårlig kjerneutvikling (5,10). Det siste har vist seg å skyldes molybdenmangel, som særlig må antas å ha årsakssammenheng med det store jerninnholdet i torva. I denne artikkelen er arealet med molybdenmangel kalt A og et tilgrensende areal uten synlige tegn til slik mangel B. Tabellene 1-3 viser kjemiske analyseresultater for torv fra 3 pro...

  7. Quantifying requirements volatility effects

    NARCIS (Netherlands)

    Kulk, G.P.; Verhoef, C.

    2008-01-01

    In an organization operating in the bancassurance sector we identified a low-risk IT subportfolio of 84 IT projects comprising together 16,500 function points, each project varying in size and duration, for which we were able to quantify its requirements volatility. This representative portfolio

  8. Idiosyncratic Volatility Puzzle

    DEFF Research Database (Denmark)

    Aslanidis, Nektarios; Christiansen, Charlotte; Lambertides, Neophytos

    from a large pool of macroeconomic and Önancial variables. Cleaning for macro-Önance e§ects reverses the puzzling negative relation between returns and idiosyncratic volatility documented previously. Portfolio analysis shows that the e§ects from macro-Önance factors are economically strong...

  9. Use of biogenic sulfide for ZnS precipitation

    NARCIS (Netherlands)

    Esposito, G.; Veeken, A.; Weijma, J.; Lens, P.N.L.

    2006-01-01

    A 600 ml continuously stirred tank reactor was used to assess the performance of a zinc sulfide precipitation process using a biogenic sulfide solution (the effluent of a sulfate-reducing bioreactor) as sulfide source. In all experiments, a proportional-integral (PI) control algorithm was used to

  10. Manure application and ammonia volatilization

    NARCIS (Netherlands)

    Huijsmans, J.F.M.

    2003-01-01

    Keywords: manure application, ammonia volatilization, environmental conditions, application technique, incorporation technique, draught force, work organization, costs Livestock manure applied on farmland is an important source of ammonia (NH3) volatilization, and NH3 is a major atmospheric

  11. En undersökning av Norwegians kriskommunikation under flygstrejken 2015. : En textanalys av Facebookinlägg och pressmeddelanden.

    OpenAIRE

    Emma, Mickelsson

    2016-01-01

    Numera lever vi i ett krissamhälle där vi nästan varje dag nås av budskap från olika typer av kriser. När en organisation drabbas av en kris är det viktigt att tänka på vilken kommunikation man använder för att nå ut med sitt budskap. Uppsatsens syfte var att undersöka hur en organisation använder sig av olika försvarsstrategier och retoriska appeller i sin kriskommunikation. Organisationen som valdes ut var flygbolaget Norwegian och deras hantering av den 11 dagar långa flygs...

  12. Slutrapport - utökad samordning av landskapsövervakning och uppföljning av Natura 2000

    OpenAIRE

    Ståhl, Göran; Gardfjell, Hans; Glimskär, Anders; Hagner, Åsa; Holm, Sören; Walheim, Mats

    2007-01-01

    I denna kortversion av 2006 års slutrapport från projektet ”utökad samordning av landskaps- övervakning och uppföljning av Natura 2000” redovisas de viktigaste resultaten på ett sätt som gör dem enklare tillgängliga för inriktningsbeslut om ambitionsnivå för uppföljnings- arbetet. Nuvarande målsättning är att Naturamoment införlivas i Nationell Inventering av Landskapet i Sverige (NILS) och Riksinventeringen av Skog (RIS) från och med 2008; under 2009 beräknas kompletteran...

  13. Selective enrichment of volatiles confirmed

    Science.gov (United States)

    de Pater, Imke

    2018-05-01

    Hydrogen sulfide gas is detected above Uranus's main cloud deck, confirming the prevalence of H2S ice particles as the main cloud component and a strongly unbalanced nitrogen/sulfur ratio in the planet's deep atmosphere.

  14. The exploitation of volatile oil

    Institute of Scientific and Technical Information of China (English)

    MENG Teng; ZHANG Da; TENG Xiangjin; LINing; HAO Zaibin

    2007-01-01

    Rose is a kind of favorite ornamental plant. This article briefly introduced the cultivation and the use of rose around the world both in ancient time and nowadays. Today, volatile oil becomes the mainstream of the rose industry. People pay attention to the effect of volatile oil; meanwhile, they speed up their research on extracting volatile oil and the ingredients.

  15. Alternative Asymmetric Stochastic Volatility Models

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2010-01-01

    textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is

  16. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild

    2015-01-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree...... such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers...... (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit...

  17. Essays on nonparametric econometrics of stochastic volatility

    NARCIS (Netherlands)

    Zu, Y.

    2012-01-01

    Volatility is a concept that describes the variation of financial returns. Measuring and modelling volatility dynamics is an important aspect of financial econometrics. This thesis is concerned with nonparametric approaches to volatility measurement and volatility model validation.

  18. Microaeration reduces hydrogen sulfide in biogas

    Science.gov (United States)

    Although there are a variety of biological and chemical treatments for removal of hydrogen sulfide (H2S) from biogas, all require some level of chemical or water inputs and maintenance. In practice, managing biogas H2S remains a significant challenge for agricultural digesters where labor and opera...

  19. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  20. Carbon a support for sulfide catalysts

    NARCIS (Netherlands)

    Vissers, J.P.R.; Lensing, T.J.; Mercx, F.P.M.; Beer, de V.H.J.; Prins, R.

    1983-01-01

    Two types of carbon materials, carbon black composite and carbon covered alumina, were studied for-their use as support for sulfide catalysts. The following parameters were varied: type of carbon black, carbon coverage of the alumina and carbon pretreatment. Pore size distributions were determined

  1. An Overview of the HomePlug AV2 Technology

    OpenAIRE

    Yonge, Larry; Abad, Jose; Afkhamie, Kaywan; Guerrieri, Lorenzo; Katar, Srinivas; Lioe, Hidayat; Pagani, Pascal; Riva, Raffaele; Schneider, Daniel M.; Schwager, Andreas

    2013-01-01

    HomePlug AV2 is the solution identified by the HomePlug Alliance to achieve the improved data rate performance required by the new generation of multimedia applications without the need to install extra wires. Developed by industry-leading participants in the HomePlug AV Technical Working Group, the HomePlug AV2 technology provides Gigabit-class connection speeds over the existing AC wires within home. It is designed to meet the market demands for the full set of future in-home networking co...

  2. A case of pancreatic AV malformation in an elderly man.

    Science.gov (United States)

    Gupta, Vipin; Kedia, Saurabh; Sonika, Ujjwal; Madhusudhan, Kumble Seetharama; Pal, Sujoy; Garg, Pramod

    2018-06-01

    A 60-year-old man presented with recurrent abdominal pain and weight loss for 6 months. Abdominal imaging showed a large vascular lesion in the head and neck of pancreas suggestive of arteriovenous malformation (AV malformation). Endoscopic ultrasound was done which showed features of AV malformation with no evidence of pancreatic malignancy. Surgery was planned for definitive treatment of malformation. Digital subtraction angiography with angioembolization was done prior to surgery to reduce vascularity of the lesion. He recovered after a pylorus preserving pancreaticoduodenectomy. Histopathology of the resected specimen confirmed the pancreatic AV malformation. There has been no recurrence at 2 years of follow-up.

  3. A new portable sulfide monitor with a zinc-oxide semiconductor sensor for daily use and field study.

    Science.gov (United States)

    Tanda, Naoko; Washio, Jumpei; Ikawa, Kyoko; Suzuki, Kengo; Koseki, Takeyoshi; Iwakura, Masaki

    2007-07-01

    For measuring oral malodor in daily clinical practice and in field study, we developed and evaluated a highly sensitive portable monitor system. We examined sensitivity and specificity of the sensor for volatile sulfur compounds (VSC) and obstructive gases, such as ethanol, acetone, and acetaldehyde. Each mouth air provided by 46 people was measured by this monitor, gas chromatography (GC), and olfactory panel and compared with each other. Based on the result, we used the monitor for mass health examination of a rural town with standardized measuring. The sensor detected hydrogen sulfide, methyl mercaptan, and dimethyl sulfide with 10-1000 times higher sensitivity than the other gases. The monitor's specificity was significantly improved by a VSC-selective filter. There were significant correlations between VSC concentration by the sulfide monitor and by GC, and by organoleptic score. Thirty-six percent of 969 examinees had oral malodor in a rural town. Seventy-eight percent of 969 examinees were motivated to take care of their oral condition by oral malodor measuring with the monitor. The portable sulfide monitor was useful to promote oral health care not only in clinics, but also in field study. The simple and quick operation system and the standardized measuring make it one of parameters of oral condition.

  4. Study on the sulfidation behavior of smithsonite

    International Nuclear Information System (INIS)

    Wu, Dandan; Wen, Shuming; Deng, Jiushuai; Liu, Jian; Mao, Yingbo

    2015-01-01

    Highlights: • Zeta potential showed that the pH IEP of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C S in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH IEP of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C S in the solution declined from 1000 × 10 −6 mol/L to 1.4 × 10 −6 mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S 2− and CO 3 2− ions

  5. Förändring av förpackning som utökning av marknadsmixen : En studie av fem snabbrörliga konsumentvaror inom livsmedelsbranschen

    OpenAIRE

    Sandström, Carolina; Eriksson, Sofie

    2011-01-01

    Denna uppsats behandlar förändring av förpackning som en möjlig utökning av produktkategorin i Kotler & Kellers utvidgade marknadsmix. I marknadsmixen behandlas förpackningen som statisk under en varas livstid och studiens syfte var att se om förpackningsförändringar istället bör ske vid flertalet tillfällen. Genom existerande litteratur identifierades tre centrala begrepp som ansågs betydelsefulla för studien; förpackning, förändring av förpackning och differentiering. Fem olika företag ...

  6. Volatile metabolites from actinomycetes

    DEFF Research Database (Denmark)

    Scholler, C.E.G.; Gurtler, H.; Pedersen, R.

    2002-01-01

    Twenty-six Streptomyces spp. were screened for their volatile production capacity on yeast starch agar. The volatile organic compounds (VOCs) were concentrated on a porous polymer throughout an 8-day growth period. VOCs were analyzed by gas chromatography with flame ionization detection...... and identified or characterized by gas chromatography-mass spectrometry. A total of 120 VOCs were characterized by retention index and mass spectra. Fifty-three compounds were characterized as terpenoid compounds, among which 18 could be identified. Among the VOCs were alkanes, alkenes, alcohols, esters, ketones....... The relationship between the excretion of geosmin and the production of spores was examined for one isolate. A good correlation between headspace geosmin and the number of spores was observed, suggesting that VOCs could be used to indicate the activity of these microorganisms in heterogeneous substrates....

  7. Minimum Tracking Error Volatility

    OpenAIRE

    Luca RICCETTI

    2010-01-01

    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 enables us to understand whether the asset manager is really active or not and, in practice, asset managers sometimes follow passively the corres...

  8. Recovering volatile liquids

    Energy Technology Data Exchange (ETDEWEB)

    Bregeat, J H

    1925-07-30

    The products of hydrogenation of alicyclic compounds, such as terpenes, for example, pinene or oil of turpentine, are used as washing liquids for absorbing vapours of volatile liquids from gases, such as natural gases from petroliferous regions, gases from the distillation of coal, lignite, schist, peat, etc. or from the cracking of heavy oils. Other liquids such as tar oils vaseline oils, cresols, etc. may be added.

  9. Understanding Interest Rate Volatility

    OpenAIRE

    Volker, Desi

    2016-01-01

    This thesis is the result of my Ph.D. studies at the Department of Finance of the Copenhagen Business School. It consists of three essays covering topics related to the term structure of interest rates, monetary policy and interest rate volatility. The rst essay, \\Monetary Policy Uncertainty and Interest Rates", examines the role of monetary policy uncertainty on the term structure of interest rates. The second essay, \\A Regime-Switching A ne Term Structure Model with Stochast...

  10. Open Source AV solution supporting In Situ Simulation

    DEFF Research Database (Denmark)

    Krogh, Kristian; Pociunas, Gintas; Dahl, Mads Ronald

    the software to meet our expectations for a portable AV system for VAD. The system would make use of “off the shelf” hardware components which are widely available and easily replaced or expanded. The developed AV software and coding is contracted to be available as Copyleft Open Source to ensure low cost...... a stable AV software that has be developed and implemented for an in situ simulation initiative. This version (1.3) is the first on released as Open Source (Copyleft) software (see QR tag). We have found that it is possible to deliver multi-camera video assisted debriefing in a mobile, in situ simulation...... environment using an AV system constructed from “off the shelf” components and Open Source software....

  11. Practically perfect: learning by doing at AVS congress.

    Science.gov (United States)

    2017-02-18

    It has been some time since Cambridge vet school last hosted the annual AVS congress, which meant that this year's congress committee faced a steep learning curve. However, as Gill Harris reports, it rose to the occasion. British Veterinary Association.

  12. Knihovna Sociologického ústavu AV ČR

    Czech Academy of Sciences Publication Activity Database

    Hesová, Nela

    2017-01-01

    Roč. 7, č. 3 (2017) E-ISSN 1805-2800 Institutional support: RVO:68378025 Keywords : library Subject RIV: AF - Documentation, Librarianship, Information Studies https://www.lib.cas.cz/casopis-informace/knihovna-sociologickeho-ustavu-av-cr/

  13. The memory of volatility

    Directory of Open Access Journals (Sweden)

    Kai R. Wenger

    2018-03-01

    Full Text Available The focus of the volatility literature on forecasting and the predominance of theconceptually simpler HAR model over long memory stochastic volatility models has led to the factthat the actual degree of memory estimates has rarely been considered. Estimates in the literaturerange roughly between 0.4 and 0.6 - that is from the higher stationary to the lower non-stationaryregion. This difference, however, has important practical implications - such as the existence or nonexistenceof the fourth moment of the return distribution. Inference on the memory order is complicatedby the presence of measurement error in realized volatility and the potential of spurious long memory.In this paper we provide a comprehensive analysis of the memory in variances of international stockindices and exchange rates. On the one hand, we find that the variance of exchange rates is subject tospurious long memory and the true memory parameter is in the higher stationary range. Stock indexvariances, on the other hand, are free of low frequency contaminations and the memory is in the lowernon-stationary range. These results are obtained using state of the art local Whittle methods that allowconsistent estimation in presence of perturbations or low frequency contaminations.

  14. Sapphire: a better material for atomization and in situ collection of silver volatile species for atomic absorption spectrometry

    Czech Academy of Sciences Publication Activity Database

    Musil, Stanislav; Matoušek, Tomáš; Dědina, Jiří

    2015-01-01

    Roč. 108, JUN (2015), s. 61-67 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Grant - others:GA AV ČR(CZ) M200311202 Institutional support: RVO:68081715 Keywords : silver * volatile species generation * sapphire tube atomizer Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.289, year: 2015

  15. US volatility cycles of output and inflation, 1919-2004: a money and banking approach to a puzzle

    Czech Academy of Sciences Publication Activity Database

    Benk, S.; Gillman, M.; Kejak, Michal

    -, č. 7150 (2009), s. 1-41 ISSN 0265-8003 Institutional research plan: CEZ:AV0Z70850503 Keywords : money and credit shocks and volatility * growth * inflation Subject RIV: AH - Economics www.cepr.org/pubs/dps/DP7150.asp

  16. EST Table: AV399390 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV399390 NV120162 11/12/09 n.h 10/09/28 100 %/181 aa ref|YP_002884244.1| Ac13-like ...yhedrovirus] 10/08/28 n.h 10/08/27 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h AV399390 NV12 ...

  17. AVS (Application Visualization System) user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Masuko, Kenji; Kato, Katsumi [Research Organization for Information Science Technology, Tokai, Ibaraki (Japan); Gorai, Kazuo; Yamazaki, Kazuhiko

    1996-03-01

    Computer and network environment for image processing has been developed and maintained under the course of establishing a distributed processing environment by the information system operating division. We introduced a server for image processing, AVS for image processing software and an animation processing system (video, frame scan converter). This report summarizes the information to use AVS and to develop and maintain computer and network environment for image processing. (author).

  18. Effekt av ulike kjemiske- og biologiske preparater på forekomsten av Fusarium og mykotoksiner i havre

    OpenAIRE

    Shakery, Bita

    2013-01-01

    Aksfusariose er en vanlig sykdom på korn forårsaket av flere ulike Fusarium-arter. En Fusarium-infeksjon på akset gir tap av avling i tillegg til en reduksjon i kvaliteten på kornet. Reduksjonen i kvalitet skjer i hovedsak gjennom produksjon av en rekke toksiske metabolitter (mykotoksiner) som kan være en helserisiko for både dyr og mennesker. I de senere årene har det vært økt fokus på Fusarium og mykotoksiner i korn både i Norge og i store deler av verden. En årsak til det...

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

    Directory of Open Access Journals (Sweden)

    In Young Sa

    2013-07-01

    Full Text Available 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.

  20. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  1. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  2. Monitoring volatile anaesthetic agents

    International Nuclear Information System (INIS)

    Russell, W.J.

    2000-01-01

    Full text: The methods that have been used for monitoring volatile anaesthetic agents depend on some physical property such as Density, Refractometry, Mass, Solubility, Raman scattering, or Infra-red absorption. Today, refractometry and infra-red techniques are the most common. Refractometry is used for the calibration of vaporizers. All anaesthetic agents increase the refractive index of the carrier gas. Provided the mixture is known then the refractive change measures the concentration of the volatile anaesthetic agent. Raman Scattering is when energy hits a molecule a very small fraction of the energy is absorbed and re-emitted at one or more lower frequencies. The shift in frequency is a function of the chemical bonds and is a fingerprint of the substance irradiated. Electromagnetic (Infra-red) has been the commonest method of detection of volatile agents. Most systems use a subtractive system, i.e. the agent in the sampling cell absorbed some of the infrared energy and the photo-detector therefore received less energy. A different approach is where the absorbed energy is converted into a pressure change and detected as sound (Acoustic monitor). This gives a more stable zero reference. More recently, the detector systems have used multiple narrow-band wavelengths in the infrared bands and by shape matching or matrix computing specific agent identification is achieved and the concentration calculated. In the early Datex AS3 monitors, a spectral sweep across the 3 micron infrared band was used to create spectral fingerprints. The recently released AS3 monitors use a different system with five very narrow band filters in the 8-10 micron region. The transmission through each of these filters is a value in a matrix which is solved by a micro computer to identify the agent and its concentration. These monitors can assist in improving the safety and efficiency of our anaesthetics but do not ensure that the patient is completely anaesthetized. Copyright (2000

  3. Monitoring volatile anaesthetic agents

    Energy Technology Data Exchange (ETDEWEB)

    Russell, W J [Royal Adelaide Hospital, SA (Australia). Department of Anaesthesia and Intensive Care

    2000-12-01

    Full text: The methods that have been used for monitoring volatile anaesthetic agents depend on some physical property such as Density, Refractometry, Mass, Solubility, Raman scattering, or Infra-red absorption. Today, refractometry and infra-red techniques are the most common. Refractometry is used for the calibration of vaporizers. All anaesthetic agents increase the refractive index of the carrier gas. Provided the mixture is known then the refractive change measures the concentration of the volatile anaesthetic agent. Raman Scattering is when energy hits a molecule a very small fraction of the energy is absorbed and re-emitted at one or more lower frequencies. The shift in frequency is a function of the chemical bonds and is a fingerprint of the substance irradiated. Electromagnetic (Infra-red) has been the commonest method of detection of volatile agents. Most systems use a subtractive system, i.e. the agent in the sampling cell absorbed some of the infrared energy and the photo-detector therefore received less energy. A different approach is where the absorbed energy is converted into a pressure change and detected as sound (Acoustic monitor). This gives a more stable zero reference. More recently, the detector systems have used multiple narrow-band wavelengths in the infrared bands and by shape matching or matrix computing specific agent identification is achieved and the concentration calculated. In the early Datex AS3 monitors, a spectral sweep across the 3 micron infrared band was used to create spectral fingerprints. The recently released AS3 monitors use a different system with five very narrow band filters in the 8-10 micron region. The transmission through each of these filters is a value in a matrix which is solved by a micro computer to identify the agent and its concentration. These monitors can assist in improving the safety and efficiency of our anaesthetics but do not ensure that the patient is completely anaesthetized. Copyright (2000

  4. Ambient Volatility of Triethyl Phosphate

    Science.gov (United States)

    2017-08-01

    of materials is predictable using Raoult’s law. This report details the measurement of the effect of water vapor partial pressure on the volatility...empirical correlation taking into account nonideal behavior was developed to enable estimation of TEPO volatility at any combination of ambient...of the second component is expected to be one-half as much as in the absence of water vapor. Similarly, the measured volatility of the second

  5. Metal uptake by lolium perenne in contaminated soils using a four-steps approach

    NARCIS (Netherlands)

    Kalis, E.J.J.; Temminghoff, E.J.M.; Visser, A.; Riemsdijk, van W.H.

    2007-01-01

    Metal bioavailability and toxicity to aquatic organisms are greatly affected by variables such as pH, hardness, organic matter, and sediment acid-volatile sulfide (AVS). Sediment AVS, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides, has been

  6. Meetprocedure voor de bepaling van Acid Volatile Sulfide en Simultaneously Extracted Metals in sediment en bodem

    NARCIS (Netherlands)

    den Hollander HA; van den Hoop MAGT; ECO

    1994-01-01

    Ter ondersteuning bij Integrale Normstelling (INS) wordt in het project ECOROUTING onderzoek uitgevoerd naar de toepasbaarheid van het evenwichtspartitieconcept bij de harmonisatie van milieukwaliteitsdoelstellingen voor de compartimenten bodem en sediment. Het onderzoek beperkt zich tot de

  7. Effect of sulfide, selenite and mercuric mercury on the growth and methylation capacity of the sulfate reducing bacterium Desulfovibrio desulfuricans

    Energy Technology Data Exchange (ETDEWEB)

    Truong, Hoang-Yen T. [Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Chen, Yu-Wei [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Belzile, Nelson, E-mail: nbelzile@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada)

    2013-04-01

    Cultures of the sulfate reducing bacteria Desulfovibrio desulfuricans were grown under anoxic conditions to study the effect of added sulfide, selenite and mercuric ions. A chemical trap consisting in a CuSO{sub 4} solution was used to control the poisoning effect induced by the bacterial production of hydrogen sulfide via the precipitation of CuS. Following the addition of Hg{sup 2+}, the formation of methylmercury (MeHg) was correlated to bacterial proliferation with most of MeHg found in the culture medium. A large fraction (50–80%) of added Hg{sup 2+} to a culture ended up in a solid phase (Hg{sup 0} and likely HgS) limiting its bioavailability to cells with elemental Hg representing ∼ 40% of the solid. Following the addition of selenite, a small fraction was converted into Se(0) inside the cells and, even though the conversion to this selenium species increased with the increase of added selenite, it never reached more than 49% of the added amount. The formation of volatile dimethylselenide is suggested as another detoxification mechanism. In cultures containing both added selenite and mercuric ions, elemental forms of the two compounds were still produced and the increase of selenium in the residual fraction of the culture suggests the formation of mercuric selenite limiting the bioavailability of both elements to cells. - Highlights: ► Detoxification mechanisms of D. desulfuricans were studied in presence of added sulfide, selenite and mercuric ions. ► The poisoning effect of H{sub 2}S added to or generated by cultures of D. desulfuricans can be controlled with a chemical trap. ► The addition of selenite to cultures triggered the formation of elemental Se and other forms of volatile and non-volatile Se. ► The addition of mercuric ions to cultures led to the production of methylmercury, volatile Hg and solid mercuric sulfide. ► With both Se and Hg added to cultures, fractionation of species in solid and liquid phases suggests the formation of HgSe.

  8. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    International Nuclear Information System (INIS)

    Wang Aijie; Liu Chunshuang; Ren Nanqi; Han Hongjun; Lee Duujong

    2010-01-01

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S 0 ), N 2 , and CO 2 , or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

  9. Microaeration for hydrogen sulfide removal in UASB reactor.

    Science.gov (United States)

    Krayzelova, Lucie; Bartacek, Jan; Kolesarova, Nina; Jenicek, Pavel

    2014-11-01

    The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Reduction of produced elementary sulfur in denitrifying sulfide removal process.

    Science.gov (United States)

    Zhou, Xu; Liu, Lihong; Chen, Chuan; Ren, Nanqi; Wang, Aijie; Lee, Duu-Jong

    2011-05-01

    Denitrifying sulfide removal (DSR) processes simultaneously convert sulfide, nitrate, and chemical oxygen demand from industrial wastewater into elemental sulfur, dinitrogen gas, and carbon dioxide, respectively. The failure of a DSR process is signaled by high concentrations of sulfide in reactor effluent. Conventionally, DSR reactor failure is blamed for overcompetition for heterotroph to autotroph communities. This study indicates that the elementary sulfur produced by oxidizing sulfide that is a recoverable resource from sulfide-laden wastewaters can be reduced back to sulfide by sulfur-reducing Methanobacterium sp. The Methanobacterium sp. was stimulated with excess organic carbon (acetate) when nitrite was completely consumed by heterotrophic denitrifiers. Adjusting hydraulic retention time of a DSR reactor when nitrite is completely consumed provides an additional control variable for maximizing DSR performance.

  11. Study on the sulfidation behavior of smithsonite

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dandan; Wen, Shuming, E-mail: shmwen@126.com; Deng, Jiushuai, E-mail: dengshuai689@163.com; Liu, Jian; Mao, Yingbo

    2015-02-28

    Highlights: • Zeta potential showed that the pH{sub IEP} of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C{sub S} in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH{sub IEP} of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C{sub S} in the solution declined from 1000 × 10{sup −6} mol/L to 1.4 × 10{sup −6} mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S{sup 2−} and CO{sub 3}{sup 2−} ions.

  12. Volatiles from solids

    Energy Technology Data Exchange (ETDEWEB)

    Loughrey, C T

    1939-08-24

    To remove volatiles from solids, such as oil shale, gases, and/or vapours are passed through a mass of the materials, the vapours and gases separated, and the vapours condensed. The volatile-containing solid materials are fed to a retort, and a shaft is driven to rotate an impeller so as to displace the liquid and create a vortex tube, which draws in gas from the atmosphere through an intake, twyer, interstices in the material in the retort, a conduit, chamber, tubes, another chamber and cylinder. This gas is carried outwardly and upwardly by the vortices in the liquid and is carried to discharge through three conduits. The vapours entrained by the gas are part condensed in the liquid and the remainder directed to a condenser. Steam may be delivered to the twyer through a nozzle of a pipe, with or without air, and combustible hydrocarbon fuel may be fed through the burner nozzle or solid fuel may be directed from feeder and combusted in the twyer.

  13. Molecular plant volatile communication.

    Science.gov (United States)

    Holopainen, Jarmo K; Blande, James D

    2012-01-01

    Plants produce a wide array of volatile organic compounds (VOCs) which have multiple functions as internal plant hormones (e.g., ethylene, methyl jasmonate and methyl salicylate), in communication with conspecific and heterospecific plants and in communication with organisms of second (herbivores and pollinators) and third (enemies of herbivores) trophic levels. Species specific VOCs normally repel polyphagous herbivores and those specialised on other plant species, but may attract specialist herbivores and their natural enemies, which use VOCs as host location cues. Attraction of predators and parasitoids by VOCs is considered an evolved indirect defence, whereby plants are able to indirectly reduce biotic stress caused by damaging herbivores. In this chapter we review these interactions where VOCs are known to play a crucial role. We then discuss the importance of volatile communication in self and nonself detection. VOCs are suggested to appear in soil ecosystems where distinction of own roots from neighbours roots is essential to optimise root growth, but limited evidence of above-ground plant self-recognition is available.

  14. Gold volatile species atomization and preconcentration in quartz devices for atomic absorption spectrometry

    Czech Academy of Sciences Publication Activity Database

    Arslan, Y.; Musil, Stanislav; Matoušek, Tomáš; Kratzer, Jan; Dědina, Jiří

    103-104, JAN-FEB (2015), s. 155-163 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Grant - others:GA AV ČR(CZ) M200311202 Institutional support: RVO:68081715 Keywords : gold * volatile species generation * quartz atomizers * atomic absorption spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.289, year: 2015

  15. Wet effluent diffusion denuder technique and the determination of volatile organic compounds in air. II. Monoterpenes

    Czech Academy of Sciences Publication Activity Database

    Sklenská, Jana; Broškovičová, Anna; Večeřa, Zbyněk

    2002-01-01

    Roč. 973, 1-2 (2002), s. 211-216 ISSN 0021-9673 R&D Projects: GA ČR GA203/98/0943 Grant - others:SPSDII(XE) EV/02/11 Institutional research plan: CEZ:AV0Z4031919 Keywords : wet effluent denuder technique * volatile organic compounds * monoterpenes Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.098, year: 2002

  16. Long-range dependence in returns and volatility of Central European Stock Indices

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav

    2010-01-01

    Roč. 2010, č. 3 (2010), s. 1-19 R&D Projects: GA ČR GD402/09/H045 Institutional research plan: CEZ:AV0Z10750506 Keywords : long-range dependence * rescaled range * modified rescaled range * bootstrapping Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2010/E/kristoufek-long-range dependence in returns and volatility of central european stock indices.pdf

  17. Assessment of trace metals pollution in estuarine sediments using SEM-AVS and ERM-ERL predictions.

    Science.gov (United States)

    Garcia, Carlos Alexandre Borges; Passos, Elisangela de Andrade; Alves, José do Patrocínio Hora

    2011-10-01

    This paper presents the distributions of the investigation of trace metals geochemistry in surface sediments of the Sergipe river estuary, northeast Brazil. Analyses were carried out by Flame or electrothermal atomic absorption spectrometry (FAAS or ETAAS). Principal component analysis was applied to results to identify any groupings among the different sampling sites. In order to determine the extent of contamination, taking into account natural variability within the region, metal concentrations were normalized relative to aluminium. Cr, Cu, Ni and Zn contamination was observed in sediments from the area receiving highest inputs of domestic wastes, while cadmium contamination occurred in sediments from the region affected by highest inflows of industrial effluents. Possible toxicity related to these metals was examined using the relationship simultaneously extracted metals/acid volatile sulfide and by comparing sediment chemical data with sediment quality guidelines ERL-ERM values. Results obtained using the two methods were in agreement and indicated that adverse effects on aquatic biota should rarely occur.

  18. Volatility Mean Reversion and the Market Price of Volatility Risk

    NARCIS (Netherlands)

    Boswijk, H.P.

    2001-01-01

    This paper analyzes sources of derivative pricing errors in a stochastic volatility model estimated on stock return data. It is shown that such pricing errors may reflect the existence of a market price of volatility risk, but also may be caused by estimation errors due to a slow mean reversion in

  19. It’s all about volatility of volatility

    DEFF Research Database (Denmark)

    Grassi, Stefano; Santucci de Magistris, Paolo

    2015-01-01

    The persistent nature of equity volatility is investigated by means of a multi-factor stochastic volatility model with time varying parameters. The parameters are estimated by means of a sequential matching procedure which adopts as auxiliary model a time-varying generalization of the HAR model f...

  20. Nanostructured silver sulfide: synthesis of various forms and their application

    Science.gov (United States)

    Sadovnikov, S. I.; Rempel, A. A.; Gusev, A. I.

    2018-04-01

    The results of experimental studies on nanostructured silver sulfide are analyzed and generalized. The influence of small particle size on nonstoichiometry of silver sulfide is discussed. Methods for the synthesis of various forms of nanostructured Ag2S including nanopowders, stable colloidal solutions, quantum dots, core–shell nanoparticles and heteronanostructures are described. The advantages and drawbacks of different synthetic procedures are analyzed. Main fields of application of nanostructured silver sulfide are considered. The bibliography includes 184 references.

  1. The role of AV and VV optimization for CRT

    Directory of Open Access Journals (Sweden)

    William W. Brabham, M.D.

    2013-06-01

    Full Text Available Cardiac resynchronization therapy is an effective therapy for patients with left ventricular systolic dysfunction and a ventricular conduction delay; however, approximately 30% of patients do not experience significant clinical improvement with this treatment. Modern devices allow individualized programming of the AV delay and VV offset, which offer the possibility of improving clinical response rates with optimized programming. AV and VV delay optimization techniques have included echocardiography, device-based algorithms, and several other novel noninvasive techniques. While an acute improvement in hemodynamic function has been clearly demonstrated with optimized device settings, long-term clinical benefit is limited. In the majority of cases, an empiric AV delay with simultaneous biventricular or left ventricular pacing is adequate. The value of optimization of these intervals in “non-responders” still requires further investigation.

  2. Lesing av delvis motstridende tekster i syvende klasse

    Directory of Open Access Journals (Sweden)

    Wenke Mork Rogne

    2013-06-01

    Full Text Available I denne artikkelen ser vi på hvilken type informasjon elever i 7. klasse vektlegger for å konstruere en sammenhengende oppsummering av fire til dels motstridende tekster. Elever møter ofte flere tekster om samme tema – multiple tekster – og vi trenger økt kunnskap om hvordan de leser slike tekster. Elevene leste fire ulike tekster om en sykkelulykke. Tekstene presenterte informasjon som var delvis sammenfallende på tvers av alle tekstene, og delvis motstridende informasjon som innebar at enkelte tekster ga ulike beskrivelser av hendelsesforløpet. Vi testet elevenes ordavkodingsferdigheter, fikk dem til å fylle ut et spørreskjema om lesevaner og vi innhentet elevenes resultater på Nasjonal leseprøve. Etter lesing ba vi elevene gi en oppsummering av sykkelulykken. Elevene gjenga relativt mer sammenfallende informasjon enn motstridende informasjon. Gode resultater på Nasjonal leseprøve ser ut til å ha en sammenheng med elevenes ferdigheter i å konstruere en sammenhengende forståelse av de fire tekstene. Elever som oppga å lese mye på Internett hadde imidlertid fått med mindre av informasjonen som var felles for de fire tekstene i sine oppsummeringer. Vi fant også en negativ sammenheng mellom fritidslesing på Internett og resultatene fra Nasjonal leseprøve. Samlet sett indikerer resultatene at når elevene skal skape sammenheng mellom flere delvis motstridende tekster, så blir sammenfallende informasjon vektlagt mer enn motstridende informasjon. Dessuten ser det ut til at de elevene som bruker mest fritid til å lese på Internett, sliter mer med å sammenfatte innholdet i de fire tekstene enn de andre elevene.

  3. EST Table: AV403981 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available terminase large subunit (DNA packaging protein A) from bacteriophage origin [Escherichia coli UMN026] 10/08/28 n.h 10/08/27 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h AV403981 pg-- ... ...AV403981 pg--0297 11/12/09 n.h 10/09/28 100 %/265 aa ref|YP_002411376.1| terminase large subunit (DNA packag...ing protein A) from bacteriophage origin [Escherichia coli UMN026] emb|CAR11828.1|

  4. Kvantifisering av overvann: Case Brøset

    OpenAIRE

    Huurnink, Jon Egenberg

    2012-01-01

    Oppgaven forsøker å vise den systemresponsen som er særegen for konvensjonelle tiltak og blå-grønne tiltak. Dette er aktuelt på Brøset bydel som en del av Fremtiden byer prosjektet og skal bygges om til boligområde. MIKE URBAN og MIKE 21 er benyttet til å lage en konseptuell modell.Ved å sammenligne sommer- og vinterforhold, i tillegg til ulike gjentaksintervaller (1, 20 og 100år), vil kurver for videreført vannmengde gi et inntrykk av tiltakenes effekt. Dette gir beslutningsstøtte for Komm...

  5. EST Table: AV398396 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV398396 NV021762 11/12/09 GO hit GO:0005622(intracellular)|GO:0008270(zinc ion bin...ding) 10/09/28 n.h 10/08/28 n.h 10/08/27 n.h 10/09/10 30 %/120 aa AGAP003111-PA Protein|2R:32505726:32508690:1|gene:AGAP003111 10/09/10 n.h 10/09/10 n.h AV398396 NV02 ...

  6. Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation conditions. Pt. 1

    International Nuclear Information System (INIS)

    Bruzzoni, P.; Burkart, A.L.; Garavaglia, R.N.

    1981-11-01

    An ASTM A 516 degree 60 carbon steel superficial protection technique submitted to a hydrogen-water sulfide corrosive medium at 2 MPa of pressure and 40-125 deg C forming on itself an iron sulfide layer was tested. Studies on pH influence, temperature, passivating mean characteristics and exposure time as well as the mechanical resistance of sulfide layers to erosion are included. (Author) [es

  7. Political institutions and economic volatility

    NARCIS (Netherlands)

    Klomp, Jeroen; de Haan, Jakob

    We examine the effect of political 'institutions' on economic growth volatility, using data from more than 100 countries over the period 1960 to 2005, taking into account various control variables as suggested in previous studies. Our indicator of volatility is the relative standard deviation of the

  8. Fundamental volatility is regime specific

    NARCIS (Netherlands)

    Arnold, I.J.M.; MacDonald, R.; Vries, de C.G.

    2006-01-01

    A widely held notion holds that freely floating exchange rates are excessively volatile when judged against fundamentals and when moving from fixed to floating exchange rates. We re-examine the data and conclude that the disparity between the fundamentals and exchange rate volatility is more

  9. 76 FR 64022 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-10-17

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide. SUMMARY: EPA is announcing... (EPCRA) section 313 toxic chemical release reporting requirements for hydrogen sulfide (Chemical...

  10. Volatile organic compounds

    International Nuclear Information System (INIS)

    Silseth, May Liss

    1998-01-01

    The goal is: Not more emission of volatile organic compounds (VOCs) than necessary. The items discussed in this presentation are the VOCs, how to calculate emission of VOCs, how to reduce or avoid them, and different recovery processes. The largest source of Norwegian emissions of non methane VOCs (NMVOCs) is offshore loading of raw petroleum. Emissions of VOCs should be reduced mainly for two reasons: (1) on sunny days NMVOCs may react with NOx to form ozon and smog close to the surface, (2) ozone and smog close to the surface may be harmful to plants and animals, and they are hazardous to human health. As for the calculation of VOC emissions, the VOCON project will release the calculation program HCGASS in 1999. This project is a cooperative project headed by SINTEF/Marintek

  11. Governmentally amplified output volatility

    Science.gov (United States)

    Funashima, Yoshito

    2016-11-01

    Predominant government behavior is decomposed by frequency into several periodic components: updating cycles of infrastructure, Kuznets cycles, fiscal policy over business cycles, and election cycles. Little is known, however, about the theoretical impact of such cyclical behavior in public finance on output fluctuations. Based on a standard neoclassical growth model, this study intends to examine the frequency at which public investment cycles are relevant to output fluctuations. We find an inverted U-shaped relationship between output volatility and length of cycle in public investment. This implies that periodic behavior in public investment at a certain frequency range can cause aggravated output resonance. Moreover, we present an empirical analysis to test the theoretical implication, using the U.S. data in the period from 1968 to 2015. The empirical results suggest that such resonance phenomena change from low to high frequency.

  12. Jakartans, Institutionally Volatile

    Directory of Open Access Journals (Sweden)

    Masaaki OKAMOTO

    2014-01-01

    Full Text Available Jakarta recently has gained even more central political attention in Indonesia since Joko Widodo (Jokowi and Basuki Purnama (Ahok became, respectively, the province’s governor and vice-governor in 2012. They started a series of eye-catching and populist programmes, drawing popular support from not only the people of Jakarta, but also among Indonesians in general. Jokowi is now even the most popular candidate for the presidential election in 2014. Their rise is phenomenal in this sense, but it is understandable if we look at Jakartan voters’ behaviour and the institutional arrangement that leads to it. Jakarta, as the national capital, has a unique arrangement in that the province has no autonomous regency or city. This paper argues that this arrangement causes Jakartans to be more politically volatile and describes how this institutional arrangement was created by analysing the minutes of the meeting to discuss the laws concerning Jakarta Province.

  13. Emerging non-volatile memories

    CERN Document Server

    Hong, Seungbum; Wouters, Dirk

    2014-01-01

    This book is an introduction to the fundamentals of emerging non-volatile memories and provides an overview of future trends in the field. Readers will find coverage of seven important memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), Multiferroic RAM (MFRAM), Phase-Change Memories (PCM), Oxide-based Resistive RAM (RRAM), Probe Storage, and Polymer Memories. Chapters are structured to reflect diffusions and clashes between different topics. Emerging Non-Volatile Memories is an ideal book for graduate students, faculty, and professionals working in the area of non-volatile memory. This book also: Covers key memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), and Multiferroic RAM (MFRAM), among others. Provides an overview of non-volatile memory fundamentals. Broadens readers' understanding of future trends in non-volatile memories.

  14. Vindkraftverk av UHPC 2.2 : En undersökning av högpresterande betong med syntetfiberarmeringen STRUX

    OpenAIRE

    Rydén, Michaéla; Nilsson, Thina

    2013-01-01

    Användandet av betong som ersättare för stål vid produktionen av vindkraftverkstorn har ökat den senaste tiden. Betongtorn är betydligt billigare än ståltorn men problem som sprickbildningar, frostsprängningar och följaktligen armeringskorrosion har uppstått bl a på grund av vibrationer från rotorn. I fundamentet i vindkraftverk kan ovan nämnda problem också uppstå och det uppfyller således inte alltid funktionskraven. Det här examensarbetet undersöker möjligheten att eliminera dessa problem ...

  15. Nonparametric methods for volatility density estimation

    NARCIS (Netherlands)

    Es, van Bert; Spreij, P.J.C.; Zanten, van J.H.

    2009-01-01

    Stochastic volatility modelling of financial processes has become increasingly popular. The proposed models usually contain a stationary volatility process. We will motivate and review several nonparametric methods for estimation of the density of the volatility process. Both models based on

  16. Control of Microbial Sulfide Production with Biocides and Nitrate in Oil Reservoir Simulating Bioreactors.

    Directory of Open Access Journals (Sweden)

    Yuan eXue

    2015-12-01

    Full Text Available Oil reservoir souring by the microbial reduction of sulfate to sulfide is unwanted, because it enhances corrosion of metal infrastructure used for oil production and processing. Reservoir souring can be prevented or remediated by the injection of nitrate or biocides, although injection of biocides into reservoirs is not commonly done. Whether combined application of these agents may give synergistic reservoir souring control is unknown. In order to address this we have used up-flow sand-packed bioreactors injected with 2 mM sulfate and volatile fatty acids (VFA, 3 mM each of acetate, propionate and butyrate at a flow rate of 3 or 6 pore volumes per day. Pulsed injection of the biocides glutaraldehyde (Glut, benzalkonium chloride (BAC and cocodiamine was used to control souring. Souring control was determined as the recovery time (RT needed to re-establish an aqueous sulfide concentration of 0.8-1 mM (of the 1.7-2 mM before the pulse. Pulses were either for a long time (120 h at low concentration (long-low or for a short time (1 h at high concentration (short-high. The short-high strategy gave better souring control with Glut, whereas the long-low strategy was better with cocodiamine. Continuous injection of 2 mM nitrate alone was not effective, because 3 mM VFA can fully reduce both 2 mM nitrate to nitrite and N2 and, subsequently, 2 mM sulfate to sulfide. No synergy was observed for short-high pulsed biocides and continuously injected nitrate. However, use of continuous nitrate and long-low pulsed biocide gave synergistic souring control with BAC and Glut, as indicated by increased RTs in the presence, as compared to the absence of nitrate. Increased production of nitrite, which increases the effectiveness of souring control by biocides, is the most likely cause for this synergy.

  17. Volatility Exposure for Strategic Asset Allocation

    OpenAIRE

    Briere, Marie; Burgues, Alexandre; Signori, Ombretta

    2008-01-01

    This paper examines the advantages of incorporating strategic exposure to equity volatility into the investment-opportunity set of a long-term equity investor. We consider two standard volatility investments: implied volatility and volatility risk premium strategies. To calibrate and assess the risk/return profile of the portfolio, we present an analytical framework offering pragmatic solutions for long-term investors seeking exposure to volatility. The benefit of volatility exposure for a co...

  18. Iron sulfide crystal growth: a literature review

    International Nuclear Information System (INIS)

    Dewar, E.J.

    1977-04-01

    Iron pyrite (FeS 2 ) is often found on trays and in heat exchangers in Girdler-Sulfide (G.S.) plants used to extract D 2 O from fresh water. A critical review of the literature was made to find: (i) what is known about FeS 2 crystal growth; (ii) which techniques could be used to study FeS 2 crystal growth experimentally; (iii) potential chemical additives that could be used in trace amounts to poison FeS 2 crystals and reduce their growth rate in G.S. plants. (author)

  19. Sulfide geochronlogy along the Southwest Indian Ridge

    Science.gov (United States)

    Yang, W.; Tao, C.; Li, H.; Liang, J.; Liao, S.

    2017-12-01

    Dragon Flag and Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones in the ultraslow-spreading Southwest Indian Ridge (SWIR). Ten subsamples from active and inactive vents of Dragon Flag hydrothermal field and twenty-eight subsamples from Duanqiao hydrothermal field were dated using the 230Th/238U method. Four main episodes of hydrothermal activity of Duanqiao were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. And sulfide samples from the nearby Dragon Flag filed at the same time and the results show that the ages of most sulfides from Dragon Flag field range from 1.496(±0.176) to 5.416 (±0.116) kyrs with the oldest age estimated at 15.997 (±0.155) kyrs Münch et al. (2001) reconstructed the evolution history of Mt. Jourdanne hydrothermal field. The age dating results indicate activity in two episodes, at 70-40 and 27-13 kyrs. The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. All these results suggest that hydrothermal activity of Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. Mt. Jourdanne is situated on an axial volcanic ridge which has both volcanic and tectonic activity. This is necessary to develop the heat source and pathways for the fluid convection, which enables the hydrothermal circulation. Hydrothermal activity in Dragon Flag Field is located next to the detachment fault termination. The detachment fault system provides a pathway for hydrothermal convection. Such style of heat source can contribute to continuous hydrothermal activity for over 1000 years. Duanqiao field is located near the central volcano and there is a hot

  20. Latent Integrated Stochastic Volatility, Realized Volatility, and Implied Volatility: A State Space Approach

    DEFF Research Database (Denmark)

    Bach, Christian; Christensen, Bent Jesper

    process is downward biased. Implied volatility performs better than any of the alternative realized measures when forecasting future integrated volatility. The results are largely similar across the stock market (S&P 500), bond market (30-year U.S. T-bond), and foreign currency exchange market ($/£ )....

  1. User guide of AVS/ITBL for numerical environmental system

    International Nuclear Information System (INIS)

    Suzuki, Yoshio; Matsumoto, Nobuko; Yamagishi, Nobuhiro; Arakawa, Takuya; Kuraishi, Hideaki

    2005-02-01

    The Center for Promotion of Computational Science and Engineering of the Japan Atomic Energy Research Institute has carried out the ITBL (Information-Technology Based Laboratory) project which is one of e-Japan priority policy programs. The goal of the ITBL project is to create the vertical research environment in which intellectual resources such as remote computers, programs and data can be shared in Japanese research institutions and cooperative studies among researchers can be supported. AVS/ITBL is the visualization tool which has been developed aiming at realizing the efficient visualization in the ITBL environment. This visualization tool is one of the tools of ITBL infrastructure software and operates in cooperation with AVS/Express. Main functions of AVS/ITBL are as follows: it can directly read data files located on remote computers, it can display and control an image on the web browser, it can collaboratively display an image among remote researchers, and it can perform visualization process as a batch. In this paper, utilization of AVS/ITBL to the numerical environmental system, which is one of the applications in ITBL project, is presented. And the outline of the operation in this utilization is indicated. (author)

  2. EST Table: AV403752 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV403752 pg--0009 10/09/28 100 %/257 aa ref|YP_002411376.1| terminase large subunit (DNA packaging... protein A) from bacteriophage origin [Escherichia coli UMN026] emb|CAR11828.1| terminase large subunit (DNA packaging

  3. EST Table: AV403922 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV403922 pg--0214 10/09/28 91 %/142 aa ref|ZP_06118881.2| DNA packaging protein FI ...[Clostridium hathewayi DSM 13479] gb|EFC94454.1| DNA packaging protein FI [Clostridium hathewayi DSM 13479

  4. EST Table: AV404246 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV404246 pg--0747 10/09/28 91 %/130 aa ref|ZP_06118881.2| DNA packaging protein FI ...[Clostridium hathewayi DSM 13479] gb|EFC94454.1| DNA packaging protein FI [Clostridium hathewayi DSM 13479

  5. EST Table: AV403894 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available ref|XP_001605691.1| PREDICTED: similar to xaa-pro dipeptidase app(e.coli) [Nasonia vitripennis] 10/08/28 52...%/206 aa gi|189241712|ref|XP_968082.2| PREDICTED: similar to xaa-pro dipeptidase app(e.coli) [Tribolium castaneum] AV403894 pg-- ...

  6. EST Table: AV399990 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV399990 br--0239 10/09/28 100 %/110 aa ref|NP_001037364.1| cellular retinoic acid .../09/10 57 %/107 aa gnl|Amel|GB15299-PA 10/09/10 59 %/107 aa gi|282165782|ref|NP_001164130.1| cellular FABP-like protein isoform 1 [Tribolium castaneum] NM_001043899 br-- ...

  7. Rektorers forståelse av mobbing i skolen

    DEFF Research Database (Denmark)

    Hansen, Helle Rabøl

    2008-01-01

    PÅ opfordring fra redaktionen gives en kommentar med dansk vinkel til den norske artikel 'Rektorers forståelse av mobbning i skolen'.Den omtalte artikel er at betragte som første trin i indførelse af en nordisk mobbeforståelse med undgangspunkt i Dan Olweus begrebsafgrænsning.Der savnes også en i...

  8. EST Table: AV400897 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV400897 br--1948 10/09/28 47 %/180 aa ref|XP_967144.2| PREDICTED: similar to corneal wound healing...TED: similar to corneal wound healing-related protein [Tribolium castaneum] CK493011 br-- ...

  9. EST Table: AV399507 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV399507 NV120319 10/09/28 70 %/144 aa ref|YP_803401.1| baculovirus repeated ORF-b [Anticars...ia gemmatalis nucleopolyhedrovirus] gb|ABI13791.1| baculovirus repeated ORF-b [Anticarsia gemmatali

  10. EST Table: AV401629 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV401629 e96h0968 10/09/28 70 %/161 aa ref|XP_002431431.1| Karyogamy protein KAR4, ...putative [Pediculus humanus corporis] gb|EEB18693.1| Karyogamy protein KAR4, putative [Pediculus humanus cor

  11. Screening av PFAS og Dekloran forbindelser i utvalgte arktiske toppredatorer

    OpenAIRE

    Schlabach, Martin; Gabrielsen, Geir Wing; Herzke, Dorte; Hanssen, Linda; Routti, Heli; Borgen, Anders

    2017-01-01

    This report summarizes the findings of a screening study into the occurrence of selected perfluorinated compounds (PFCs) and dechloranes in Arctic top predators. The emerging PFCs F53 F53B, and PFBS were not detected neither in bird eggs nor in mammals. However, different dechloranes were detected in all samples. Screening av PFAS og Dekloran forbindelser i utvalgte arktiske toppredatorer

  12. EST Table: AV400925 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV400925 br--1989 10/09/28 35 %/122 aa ref|XP_967620.1| PREDICTED: similar to anopheles stephen...nl|Amel|GB19565-PA 10/09/10 35 %/122 aa gi|91093471|ref|XP_967620.1| PREDICTED: similar to anopheles stephensi ubiquitin, putative [Tribolium castaneum] FS914988 br-- ...

  13. EST Table: AV400204 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV400204 br--0896 10/09/28 36 %/111 aa ref|XP_967620.1| PREDICTED: similar to anopheles stephen...093471|ref|XP_967620.1| PREDICTED: similar to anopheles stephensi ubiquitin, putative [Tribolium castaneum] FS914988 br-- ...

  14. Kinetic analysis of volatile formation in milk subjected to pressure-assisted thermal treatments.

    Science.gov (United States)

    Vazquez-Landaverde, P A; Qian, M C; Torres, J A

    2007-09-01

    Volatile formation in milk subjected to pressure-assisted thermal processing (PATP) was investigated from a reaction kinetic analysis point of view to illustrate the advantages of this technology. The concentration of 27 volatiles of different chemical class in milk subjected to pressure, temperature, and time treatments was fitted to zero-, 1st-, and 2nd-order chemical reaction models. Temperature and pressure effects on rate constants were analyzed to obtain activation energy (E(a)) and activation volume (deltaV*) values. Hexanal, heptanal, octanal, nonanal, and decanal followed 1st-order kinetics with rate constants characterized by E(a) values decreasing with pressure reflecting negative deltaV* values. Formation of 2-methylpropanal, 2,3-butanedione, and hydrogen sulfide followed zero-order kinetics with rate constants increasing with temperature but with unclear pressure effects. E(a) values for 2-methylpropanal and 2,3-butanedione increased with pressure, that is, deltaV* > 0, whereas values for hydrogen sulfide remained constant, that is, deltaV* = 0. The concentration of all other volatiles, including methanethiol, remained unchanged in pressure-treated samples, suggesting large negative deltaV* values. The concentration of methyl ketones, including 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, 2-decanone, and 2-undecanone, was independent of pressure and pressure-holding time. PATP promoted the formation of few compounds, had no effect on some, and inhibited the formation of volatiles reported to be factors of the consumer rejection of "cooked" milk flavor. The kinetic behavior observed suggested that new reaction formation mechanisms were not likely involved in volatile formation in PATP milk. The application of the Le Chatelier principle frequently used to explain the high quality of pressure-treated foods, often with no supporting experimental evidence, was not necessary.

  15. Microbial selenium sulfide reduction for selenium recovery from wastewater

    NARCIS (Netherlands)

    Hageman, S.P.W.; Weijden, van der R.D.; Stams, A.J.M.; Cappellen, van P.; Buisman, C.J.N.

    2017-01-01

    Microbial reduction of selenium sulfide (SeS2) is a key step in a new treatment process to recover selenium from selenate and selenite streams. In this process, selenate is first reduced to selenite, and subsequently selenite is reduced by sulfide and precipitates from the solution as SeS2. The

  16. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However...

  17. Technetium behavior in sulfide and ferrous iron solutions

    International Nuclear Information System (INIS)

    Lee, S.Y.; Bondietti, E.A.

    1982-01-01

    Pertechnetate oxyanion ( 99 TcO 4- ), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (ν-Fe 2 O 3 ) and geothite (α-FeOOH) were the dominant minerals in the precipitate obtained from the TcO 4- -ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO 4- -ferrous iron-sulfide reaction, was transformed to goethite and hematite (α-Fe 2 O 3 ) on aging. The black precipitate obtained from the TcO 4- -sulfide reaction was poorly crystallized technetium sulfide (Tc 2 S 7 ) which was insoluble in both acid and alkaline solution in the absence of strong oxidents. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals

  18. Sulfidation of carbon-supported iron oxide catalysts

    NARCIS (Netherlands)

    Ramselaar, W.L.T.M.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Oers, van E.M.; Kraan, van der A.M.

    1989-01-01

    The sulfidation of carbon-supported iron oxide catalysts was studied by means of in-situ Mössbauer spectroscopy at temperatures down to 4.2 K. The catalysts were dried in two different ways and then sulfided in a flow of 10% H2S in H2 at temperatures between 293 and 773 K. Thiophene

  19. Analysis of AVS-penogram in 3000 impotent patients

    Energy Technology Data Exchange (ETDEWEB)

    Minn, Young Guy; Choi, Hyung Ki [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1994-09-01

    Audio visual simulation penogram(AVS-penogram) is used as a screening method for evaluation of erectile dysfunction. In this study, 3000 patients were evaluated from Dec. 1986 to Dec. 1992 and finally diagnosed by comprehensive diagnostic methods. The patients were classified according to AVS-penogram curves into 4 types and correlated with the patient`s final diagnosis. For 800 patients who were evaluated with combined AVS-penogram and NPT monitoring, compatibility ratios between psychogenic and organic group were compared. After correlating each of the curve type with the patients and comparing erotic and nocturnal erection, following results were obtained. 1. The mean age of the patients was 41.25 years. 2. The overall rate of final diagnosis were 57.5%, 14.3%, 8.9% in psychogenic, arteriogenic and veogenic impotence. 3. Type I group was proved as psychogenic impotence in 87% of the patients. 4. Type IIA group was proved as organic impotence in 79% of the patients and most of them had neurogenic and arteriogenic impotence. 5. Type IIB group was proved as psychogenic impotence in 51%, organic impotence in 49% of the patients. Among the organic impotence group, most of them had arteriogenic, venogenic and neurogenic impotence. The difference of both group was statically insignificant. 6. Type IIC group was proved as psychogenic impotence in 39%, organic impotence in 61% of the patients. Further studies are needed for sub-classification of both groups. 7. The compatibility ratio of the AVS-penogram and NPTM was 85.9% in psychogenic group with normal finding in both tests and 44.7% in organic group with abnormal finding in both tests. In conclusion, AVS-penogram is a primary diagnostic method in screening impotent patients and type I is regarded as psychogenic impotence. In Type IIB and IIC, sub-classification of curve type is needed for differential diagnosis between psychogenic and organic impotence. (Abstract Truncated)

  20. Parallel Prediction of Stock Volatility

    Directory of Open Access Journals (Sweden)

    Priscilla Jenq

    2017-10-01

    Full Text Available Volatility is a measurement of the risk of financial products. A stock will hit new highs and lows over time and if these highs and lows fluctuate wildly, then it is considered a high volatile stock. Such a stock is considered riskier than a stock whose volatility is low. Although highly volatile stocks are riskier, the returns that they generate for investors can be quite high. Of course, with a riskier stock also comes the chance of losing money and yielding negative returns. In this project, we will use historic stock data to help us forecast volatility. Since the financial industry usually uses S&P 500 as the indicator of the market, we will use S&P 500 as a benchmark to compute the risk. We will also use artificial neural networks as a tool to predict volatilities for a specific time frame that will be set when we configure this neural network. There have been reports that neural networks with different numbers of layers and different numbers of hidden nodes may generate varying results. In fact, we may be able to find the best configuration of a neural network to compute volatilities. We will implement this system using the parallel approach. The system can be used as a tool for investors to allocating and hedging assets.

  1. The effect of ginger and garlic addition during cooking on the volatile profile of grass carp (Ctenopharyngodon idella) soup.

    Science.gov (United States)

    Li, Jin-Lin; Tu, Zong-Cai; Zhang, Lu; Sha, Xiao-Mei; Wang, Hui; Pang, Juan-Juan; Tang, Ping-Ping

    2016-08-01

    Ginger and garlic have long been used in Asian countries to enhance the flavor and to neutralize any unpleasant odors present in fish soup. The purpose of this study was to evaluate the change in the amount of volatile components present in fish soup compared to boiled water solutions of ginger and garlic. The fish soup was prepared by boiling oil-fried grass carp ( Ctenopharyngodon idella ) with or without ginger and/or garlic. Generally, boiling garlic and ginger in water led to a decrease in the amount of the principal volatile constituents of these spices, together with the formation of some new volatiles such as pentanal, hexanal, and nonanal. The results showed that 16 terpenes present in raw ginger, predominantly camphene, β -phellandrene, β -citral, α -zingiberene, and ( E )-neral, were detected in fish soup with added ginger and thus remained in the solution even after boiling. Similarly, 2-propen-1-ol and three sulfur compounds (allyl sulfide, diallyl disulfide, and diallyl trisulfide) present in raw garlic, were present in trace amounts in the boiled garlic solution, but were present in considerably larger amounts in the boiled fish solution with garlic or garlic plus ginger. In conclusion, the effect of adding spices on the volatile profile of grass carp soup can be attributed to the dissolution of flavor volatiles mainly derived from raw spices into the solution, with few additional volatiles being formed during boiling. In addition, boiling previously fried grass carp with spices led to enhanced volatile levels compared to boiled spice solutions.

  2. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  3. Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

    Directory of Open Access Journals (Sweden)

    Christopher S. Williams

    1999-06-01

    Full Text Available Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice.

  4. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    risks and corrosion of concrete and metals. Most of the problems relate to the buildup of hydrogen sulfide in the atmosphere of sewer networks. In this respect, the processes of the sulfur cycle are of fundamental importance in ultimately determining the extent of such problems. This study focused...... calibrated and validated against field data. In the extension to the WATS model, sulfur transformations were described by six processes: 1. Sulfide production taking place in the biofilm and sediments covering the permanently wetted sewer walls; 2. Biological sulfide oxidation in the permanently wetted...... to the sewer atmosphere, potentially resulting in concrete corrosion. The extended WATS model represents a major improvement over previously developed models for prediction of sulfide buildup in sewer networks. Compared to such models, the major processes governing sulfide buildup in sewer networks...

  5. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Barzegar, Mohsen [Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Jabbari, Ali [K. N. Toosi University, Tehran (Iran, Islamic Republic of); Esmaeili, Majid [Razi University, Kermanshah (Iran, Islamic Republic of)

    2003-09-15

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

  6. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    International Nuclear Information System (INIS)

    Barzegar, Mohsen; Jabbari, Ali; Esmaeili, Majid

    2003-01-01

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples

  7. Kokken lagar mat! Utøving og utvikling av yrkeskunnskap på kjøkenet sett i lys av 2300 år gamle kunnskapsformer.

    OpenAIRE

    Gascogne, Marit

    2011-01-01

    Master i yrkespedagogikk Tema for masteroppgåva er utøving og utvikling av yrkeskunnskap i kokkfaget. Bakgrunnen for arbeidet er resultat frå andre forskingsprosjekt i masterstudiet og innføringa av den nye reforma, kunnskapsløftet, i den vidaregåande skulen. Analyse av litteratur, observasjon og intervju av yrkesutøvarar er metodane som er brukt for å finne svar på problemstillinga: Korleis kan Aristoteles sine gnosis-former brukast til å skildre yrkeskunnskap og utvikling av yrkesk...

  8. Volatiles in the Martian regolith

    International Nuclear Information System (INIS)

    Clark, B.C.; Baird, A.K.

    1979-01-01

    An inventory of released volatiles on Mars has been derived based upon Viking measurements of atmospheric and surface chemical composition, and upon the inferred mineralogy of a ubiquitous regolith, assumed to average 200m in depth. This model is consistent with the relative abundances of volatiles (except for S) on the Earth's surface, but implies one-fifteenth of the volatile release of Earth if starting materials were comparable. All constituents are accommodated as chemical components of, or absorbed phases on, regolith materials--without the necessity of invoking unobservable deposits of carbonates, nitrates, or permafrost ice

  9. Consistent ranking of volatility models

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger

    2006-01-01

    We show that the empirical ranking of volatility models can be inconsistent for the true ranking if the evaluation is based on a proxy for the population measure of volatility. For example, the substitution of a squared return for the conditional variance in the evaluation of ARCH-type models can...... variance in out-of-sample evaluations rather than the squared return. We derive the theoretical results in a general framework that is not specific to the comparison of volatility models. Similar problems can arise in comparisons of forecasting models whenever the predicted variable is a latent variable....

  10. Magmatic Hydrothermal Fluids: Experimental Constraints on the Role of Magmatic Sulfide Crystallization and Other Early Magmatic Processes in Moderating the Metal Content of Ore-Forming Fluids

    Science.gov (United States)

    Piccoli, P. M.; Candela, P. A.

    2006-05-01

    It has been recognized for some time that sulfide phases, although common in intermediate-felsic volcanic rocks, are not as common in their plutonic equivalents. That sulfide crystallization, or the lack thereof, is important in the protracted magmatic history of porphyry Cu and related systems is supported by the work of e.g., Rowins (2000). Candela and Holland (1986) suggested that sulfide crystallization could moderate the ore metal concentrations in porphyry environments. Experiments show clearly that Au and Cu can partition into Cl-bearing vapor and brine. This effect can be enhanced by S (Simon, this session). However, in some instances enhances this effect. That is, the partitioning of Au and Cu into vapor+brine is highly efficient (e.g. Simon et al. 2003; Frank et al 2003). This suggests that if sulfides do not sequester ore metals early during the history of a magma body from the melt, they will partition strongly into the volatile phases. Whether volatile release occurs in the porphyry ore environment, or at deeper levels upon magma rise, is a yet unsolved question. Little is known about deep release of volatiles (during magma transport at lower- to mid-crustal levels). Saturation of melts with a CO2-bearing fluid could happen at levels much deeper than those typical of ore formation. CO2 is released preferentially, so a high CO2 concentration in fluids in the porphyry ore environment argues against deep fluid release. Of course, this depends upon the specific processes of crystallization and fluid release, which may be complex. Our experiments on sulfides have concentrated on pyrrhotite and Iss. Our partitioning data for Po/melt exhibit wide variations from metal to metal: Cu (2600); Co (170); Au (140); Ni (100); Bi, Zn and Mn (2). These results suggest that crystallization of Po can contribute to variable ore metal ratios (e.g. Cu/Au). Other sulfides behave differently. If a melt is Iss (Cpy) saturated, then Cu will be buffered at a high value, and Au

  11. Anoxic sulfide biooxidation using nitrite as electron acceptor

    International Nuclear Information System (INIS)

    Mahmood, Qaisar; Zheng Ping; Cai Jing; Wu Donglei; Hu, Baolan; Li Jinye

    2007-01-01

    Biotechnology can be used to assess the well being of ecosystems, transform pollutants into benign substances, generate biodegradable materials from renewable sources, and develop environmentally safe manufacturing and disposal processes. Simultaneous elimination of sulfide and nitrite from synthetic wastewaters was investigated using a bioreactor. A laboratory scale anoxic sulfide-oxidizing (ASO) reactor was operated for 135 days to evaluate the potential for volumetric loading rates, effect of hydraulic retention time (HRT) and substrate concentration on the process performance. The maximal sulfide and nitrite removal rates were achieved to be 13.82 and 16.311 kg/(m 3 day), respectively, at 0.10 day HRT. The process can endure high sulfide concentrations, as the sulfide removal percentage always remained higher than 88.97% with influent concentration up to 1920 mg/L. Incomplete sulfide oxidation took place due to lower consumed nitrite to sulfide ratios of 0.93. It also tolerated high nitrite concentration up to 2265.25 mg/L. The potential achieved by decreasing HRT at fixed substrate concentration is higher than that by increasing substrate concentration at fixed HRT. The process can bear short HRT of 0.10 day but careful operation is needed. Nitrite conversion was more sensitive to HRT than sulfide conversion when HRT was decreased from 1.50 to 0.08 day. Stoichiometric analyses and results of batch experiments show that major part of sulfide (89-90%) was reduced by nitrite while some autooxidation (10-11%) was resulted from presence of small quantities of dissolved oxygen in the influent wastewater. There was ammonia amassing in considerably high amounts in the bioreactor when the influent nitrite concentration reached above 2265.25 mg/L. High ammonia concentrations (200-550 mg/L) in the bioreactor contributed towards the overall inhibition of the process. Present biotechnology exhibits practical value with a high potential for simultaneous removal of nitrite

  12. Carbon steel protection in G.S. (Girlder sulfide) plants. Pressure influence on iron sulfide scales formation. Pt. 5

    International Nuclear Information System (INIS)

    Delfino, C.A.; Lires, O.A.; Rojo, E.A.

    1987-01-01

    In order to protect carbon steel towers and piping of Girlder sulfide (G.S.) experimental heavy water plants against corrosion produced by the action of aqueous solutions of hydrogen sulfide, a method, previously published, was developed. Carbon steel, exposed to saturated aqueous solutions of hydrogen sulfide, forms iron sulfide scales. In oxygen free solutions evolution of corrosion follows the sequence: mackinawite → cubic ferrous sulfide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite-pyrite or pyrite are the most protective layers (these are obtained at 130 deg C, 2MPa, for periods of 14 days). Experiments, at 125 deg C and periods of 10-25 days, were performed in two different ways: 1- constant pressure operations at 0.5 and 1.1 MPa. 2- variable pressure operation between 0.3-1 MPa. In all cases pyrrotite-pyrite scales were obtained. (Author) [es

  13. Påliteligheten av selvrapportert alkoholkonsum. Svalbardstudien 1988-89

    Directory of Open Access Journals (Sweden)

    Georg Høyer m. fl

    2009-10-01

    Full Text Available  SAMMENDRAGSvalbard er spesielt godt egnet til å vurdere påliteligheten av selvrapportert alkoholkonsum. På grunn av detlave prisnivået for alkohol er ulovlig import eller hjemmeproduksjon av alkohol ukjent på Svalbard. Dessutener samfunnet lite og oversiktlig, slik at det er praktisk mulig å undersøke hele befolkningen. I den aktuellestudien registrerte vi alt salg av alkohol til fastboende nordmenn på Svalbard i oktober og november 1988. Isamme tidsperiode ble alle nordmenn 18 år eller eldre invitert til å ta del i en helseundersøkelse der det inngikkspørsmål om alkoholbruk. Vi fant at selvrapportert alkoholkonsum utgjorde rundt 40% av salgsvolumet.På grunn av de spesielle forhold når det gjelder alkoholomsetning på Svalbard er det grunn til å anta atestimatet i denne studien er mer pålitelig sammenlignet med tilsvarende studier fra andre områder.Høyer G, Nilssen O, Brenn T, Schirmer H. The reliability of self-reported alcohol consumption.The Svalbard study 1988-89. Nor J Epidemiol 1996; 6 (1: 109-113.ENGLISH SUMMARYThe Norwegian island of Spitzbergen, Svalbard offers a unique setting for validation studies on self-reportedalcohol consumption. No counterfeit production or illegal import exists, thus making a complete registrationof all sources of alcohol possible. In this study we recorded sales from all agencies selling alcohol onSvalbard over a two month period in 1988. During the same period all adults living permanently on Svalbardwere invited to take part in a health screening. As part of the screening a self-administered questionnaire onalcohol consumption was introduced to the participants. We found that the self-reported volume accounted forapproximately 40 percent of the sales volume. Because of the unique situation applying to Svalbard, theestimate made in this study is believed to be more reliable compared to other studies using sales volume tovalidate self-reports.

  14. Kinetics of aerobic oxidation of volatile sulfur compounds in wastewater and biofilm from sewers

    DEFF Research Database (Denmark)

    Rudelle, Elise Alice; Vollertsen, Jes; Hvitved-Jacobsen, Thorkild

    2013-01-01

    Laboratory experiments were conducted to investigate the kinetics of aerobic chemical and biological oxidation of selected odorous volatile sulfur compounds (VSCs) by wastewater and biofilm from sewers. The VSCs included methyl mercaptan (MeSH), ethyl mercaptan (EtSH), dimethyl sulfide (DMS......-spot downstream of a force main and the other was a gravity sewer transporting young aerobic wastewater. The kinetics of VSC oxidation for both wastewater and suspended biofilm samples followed a first-order rate equation. The average values of the reaction rate constants demonstrated the following order...... in the aerobic wastewater....

  15. Stochastic volatility and stochastic leverage

    DEFF Research Database (Denmark)

    Veraart, Almut; Veraart, Luitgard A. M.

    This paper proposes the new concept of stochastic leverage in stochastic volatility models. Stochastic leverage refers to a stochastic process which replaces the classical constant correlation parameter between the asset return and the stochastic volatility process. We provide a systematic...... treatment of stochastic leverage and propose to model the stochastic leverage effect explicitly, e.g. by means of a linear transformation of a Jacobi process. Such models are both analytically tractable and allow for a direct economic interpretation. In particular, we propose two new stochastic volatility...... models which allow for a stochastic leverage effect: the generalised Heston model and the generalised Barndorff-Nielsen & Shephard model. We investigate the impact of a stochastic leverage effect in the risk neutral world by focusing on implied volatilities generated by option prices derived from our new...

  16. Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometry based on the use of non-volatile buffers

    Czech Academy of Sciences Publication Activity Database

    Gottardo, R.; Mikšík, Ivan; Aturki, Z.; Sorio, D.; Seri, C.; Fanali, S.; Tagliaro, F.

    2012-01-01

    Roč. 33, č. 4 (2012), s. 599-606 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z50110509 Keywords : capillary electrophoresis * drugs of abuse * non-volatile buffer * CE-MS Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.261, year: 2012

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

    Czech Academy of Sciences Publication Activity Database

    Turner, C.; Parekh, B.; Walton, Ch.; Španěl, Patrik; Smith, D.; Evans, M.

    2008-01-01

    Roč. 22, č. 4 (2008), s. 526-532 ISSN 0951-4198 Institutional research plan: CEZ:AV0Z40400503 Keywords : SIFT-MS * volatile compounds * aldehydes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.772, year: 2008

  18. Biomineralization of radioactive sulfide minerals in strong acidic Tamagawa hot springs

    International Nuclear Information System (INIS)

    Tazaki, Kazue; Watanabe, Hiroaki

    2004-01-01

    Bioaccumulation of radioactive sulfide minerals by bacteria in strong acidic hot spring water was found at Tamagawa Hot Springs, Akita prefecture in Japan. The hot spring water produces Hokutolite of radioactive minerals high radium and radon. The β-ray measurements of sediments and biofilms indicate 1850-2420 and 5700 cpm, respectively, which are 50-100 times higher than that of the water and the air (50-90 cpm). The characteristics of hot spring water show pH (1.2), Eh (140 mV), EC (29 mS/cm), DO (0.8 mg/l), and water temperature (99.5degC), indicating extremely strong acidic and reducing conditions. The hot spring water contains mainly HCl associated with high concentrations of Ca 2+ , Al 3+ , Fe 2+ , HSO 4 - and SO 4 2- . SEM-EDX and TEM demonstrate some insight into how microorganisms affect the chemistry and microbiological characteristics of the strong acidic surroundings with high S, As, Ba, and Ca contents in biofilms. Especially SEM-EDX, ED-XRF, and STEM-EDX elemental content maps illustrate the distribution of sulfur-bearing compounds of barite (BaSO 4 ), gypsum (CaSO 4 ·2H 2 O), elemental sulfur (S) and orpiment(As 2 S 3 ) in the reddish orange biofilms. The presence of a hydrogen sulfide-rich (H 2 S) thermal spring and gypsum deposits suggest the volatilization of H 2 S from the spring water, oxidation of the H 2 S gas to sulfuric acid, and reaction of the sulfuric acid. TEM micrographs of bacteria in the biofilms reveal in detail the intimate connections between biological and mineralogical processes that the cells are entirely accumulated with spherical grains, 100∼200 nm in diameter. The relationship among sulfide minerals, such as barite, gypsum, sulfur, orpiment, and Hakutolite, associated with bacteria implies that heavy metals have been transported from strong acidic hot spring water to sediments through bacteria metabolism. It is possible that the capability of radioactive sulfide biofilms for heavy metal immobilization can be used to

  19. Hvilken rolle spiller hybrid shopping i kundereisen ved kjøp av kosmetikk?

    OpenAIRE

    Varem, Andrea; Nervik, Lene

    2017-01-01

    Temaet for denne bacheloroppgaven er hybrid shopping i kundereisen ved kjøp av kosmetikk. Etter en omfattende gjennomgang av eksisterende teori rundt kundereisen fikk vi et inntrykk av at det er et gap i forskningen knyttet til kundereisen ved kjøp av kosmetikk, på tross av størrelsen på dette markedet. Det vi fant av teori på feltet var i stor grad basert på kvantitative undersøkelser, og vi ønsker derfor å belyse kundereisen i denne konteksten gjennom et kvalitativt forskningsdesign. Med ut...

  20. Overvåking av jordboende sopp i Røsskleiva NR, Bamble 2016

    OpenAIRE

    Brandrud, Tor Erik; Dima, Bàlint

    2017-01-01

    Brandrud, T.E. & Dima, B. 2017. Overvåking av jordboende sopp i Røsskleiva NR, Bamble 2016. – NINA Kortrapport 80. 15 s. Kartlegging (start av overvåking) av habitat-spesifikke, jordboende kalksopper i nordre del av Røsskleiva NR ble gjennomført i 2016, før oppstart av skjøtselstiltak med storfébeiting. Tilsammen 27 habitat-spesifikke arter, inkludert 18 rødlistede arter ble registrert i løpet av to registreringsrunder i 2016. Funnene fordelte seg på 10 kalkbarskogsopper, 5 kalklinde-skogs...

  1. Validation of a Real-time AVS Encoder on FPGA

    Directory of Open Access Journals (Sweden)

    Qun Fang Yuan

    2014-01-01

    Full Text Available A whole I frame AVS real-time video encoder is designed and implemented on FPGA platform in this paper. The system uses the structure of the flow calculation, coupled with a dual-port RAM memory between/among the various functional modules. Reusable design and pipeline design are used to optimize various encoding module and to ensure the efficient operation of the pipeline. Through the simulation of ISE software and the verification of Xilinx Vritex-4 pro platform, it can be seen that the highest working frequency can be up to 110 MHz, meeting the requirements of the whole I frame real- time encoding of AVS in CIF resolution.

  2. Leaning av arbetspunkt för urindiagnostik

    OpenAIRE

    Romar, Arne Johannes

    2017-01-01

    Lean är en metod som ämnar förbättra arbetsprocesser, öka kvalitén och förhindra slöseri av resurser. Fler och fler företag och institutioner i västvärlden har den senaste tiden börjat implementera läran och verktygen som ursprungligen kom från Toyota och deras produktionssystem. Sjukhus och sjukhuslaboratorier är inget undantag, patienterna och provmängderna blir större samtidigt som krav på inbesparningar sker. Därför behövs alternativa lösningar i form av lean för att få tillstånd en effek...

  3. Wirevagn : Utvecklingen av en utrullare för hisslinor

    OpenAIRE

    Rehnsfeldt, Patrik

    2014-01-01

    Kandidatexamensarbetet som utgick från en förfrågan från företaget Irongrip AB hade som mål att utveckla ett produktförslag på en utlindare av stålvajer för hissmontörer. Irongrip AB som tillverkar och säljer verktyg för hantering av stålvajer hade uppmärksammat att en efterfrågan på en sådan produkt fanns på marknaden då befintliga lösningar var bristfälliga och inte hade alla de funktioner som är önskvärda hos en sådan produkt.Arbetet inleddes med en förstudie där studiebesök vid lindragnin...

  4. Nyttan av franchising i den svenska fastighetsmäklarbranschen

    OpenAIRE

    Herke, Marie; Olivers, Marielle

    2012-01-01

    Franchising är det mest vanliga kedjekonceptet i fastighetsmäklarbranschen och flera av de största fastighetsmäklarkedjorna är franchisekedjor. De fristående mäklarbyråerna får allt svårare att klara sig i den ökade konkurrensen. Det är främst fristående mäklarbyråer på mindre orter med ett etablerat varumärke samt nischade mäklarbyråer som klarar sig i konkurrensen med de stora kedjorna. På senare år har antalet kedjeanslutna fastighetsmäklare ökat betydligt och flertalet av mäklarkedjorna ä...

  5. Utforming av stålrammer til ridehall

    OpenAIRE

    Halvorsrud, Roar

    2013-01-01

    NORSK: Oppgaven går ut på å dimensjonere forskjellige bærerammer til en ridehall på kobberud gård i Lier kommune i Buskerud. Kriterier i oppgaven er at alle forbindelser mellom søyler og bjelker skal kunne utføres som en boltet forbindelse for en så praktisk oppreising av bygget som mulig. Det gir også mulighet for og montere selve bæresystemet på egenhånd om man har nødvendig utstyr. Det er dermed viktig at man bruker så lite stål som mulig for å redusere vekt av søyler og bjelker. Bearbe...

  6. Occupational exposure to hydrogen sulfide: management of hydrogen sulfide exposure victims (Preprint No. SA-5)

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1989-04-01

    National Institute of Occupational Safety and Health, U.S.A. has listed 73 industries with potential exposure to hydrogen sulphide. Though the toxicity of hydrogen sulfide is known to mankind since the beginning of seventeenth century the exact mode of its toxicity and effective therapeutic regimen remains unclear as yet. This paper presents current thoughts on the toxicity of this substance and a discussion on the role of various antidotes used in H 2 S poisoning. (autho r)

  7. Aqueous studies of hydrogen sulfide releases from a heavy water extraction facility

    International Nuclear Information System (INIS)

    Kiser, D.L.

    1979-03-01

    Upsets in the operation of the wastewater strippers in the 400 Area of the Savannah River Plant have released hydrogen sulfide in quantities as large as 1800 kg to the effluent stream. Fish kills in the swamp area of Beaver Dam Creek have occurred following the large releases. A literature survey revealed volatilization and oxidation as the major loss mechanisms of H 2 S. Laboratory investigations supported the literature survey. The computer code for pollutant transport in a stream, LODIPS, has an option to account for sink-source effects in a stream. Volatilization and oxidation rate constants were developed for the sink option from two H 2 S releases (18 kg and 118 kg) and results were predicted with LODIPS. Based on the predicted concentration-time profiles for various hypothetical cases, releases as small as 568 kg if discharged over a 30-minute period or releases as large as 1818 kg if discharged over a 360-minute period or less are lethal to swamp fish

  8. Electrical storm after CRT implantation treated by AV delay optimization.

    Science.gov (United States)

    Combes, Nicolas; Marijon, Eloi; Boveda, Serge; Albenque, Jean-Paul

    2010-02-01

    We present a case of symptomatic ischemic heart failure with an indication for cardiac resynchronization and implantable cardiac defibrillator therapy in primary prevention. After implantation, the patient developed a severe electrical storm with multiple shocks. Hemodynamic improvement based only on AV delay, guided by echocardiography and ECG, brought about a dramatic improvement in the situation. We discuss the pathophysiology of electrical storm occurring immediately after LV pacing.

  9. EST Table: AV401797 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV401797 heS00172 10/09/28 94 %/235 aa ref|NP_001036831.1| saposin-related [Bombyx ...9/10 low homology 10/09/10 low homology 10/09/10 41 %/191 aa gi|91077504|ref|XP_966852.1| PREDICTED: similar to saposin isoform 1 [Tribolium castaneum] FS791050 heS0 ...

  10. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  11. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wang Aijie, E-mail: waj0578@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Liu Chunshuang; Ren Nanqi; Han Hongjun [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Lee Duujong [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-06-15

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S{sup 0}), N{sub 2}, and CO{sub 2}, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 < C/S < 3.0 with influent sulfide concentration of 400-1000 mg/L. At >1000 mg/L influent sulfide, however, the DSR system will break down.

  12. Inkludering av ungdom med minoritetsbakgrunn i NIF-organisert idrett

    Directory of Open Access Journals (Sweden)

    Mari Kristin Sisjord

    2014-10-01

    Full Text Available Norges Idrettsforbund og Olympiske og Paralympiske Komité (NIF har en uttalt målsetting om en åpen og inkluderende idrett. Hvordan kommer dette til uttrykk i den praktiske virksomheten? Denne artikkelen, som bygger på data fra en undersøkelse om likestilling og mangfold i den organiserte idretten (NIF, retter søkelyset mot arbeid med inklusjon av ungdom med minoritetsbakgrunn på ulike organisasjonsnivå i NIF: særforbund, idrettskretser og idrettslag. Datamaterialet er kvalitative intervju med representanter fra ulike organisasjonsnivå. Resultatene viser at NIFs overordnede politikk i varierende grad nedfelles i særforbundenes virksomhet, i idrettskretsene og i idrettslagene. Av særforbundene skiller Fotballforbundet og Klatreforbundet seg ut som aktive pådrivere i arbeidet med inkludering. Mange idrettslag oppfattet slike spørsmål som lite aktuelle i sitt rekrutteringsområde. Representanter for lag som hadde erfaring med inkludering og rekruttering av minoritetsungdom, tilkjennega varierte erfaringer og synspunkter.

  13. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  14. Eelgrass fairy rings: sulfide as inhibiting agent

    DEFF Research Database (Denmark)

    Borum, Jens; Raun, Ane-Marie Løvendahl; Hasler-Sheetal, Harald

    2014-01-01

    specifically, for the apparent die- off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m−2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots...... expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were...... substantial invasion of sulfide from the sediment. neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic...

  15. On the pelletizing of sulfide molybdenite concentrate

    International Nuclear Information System (INIS)

    Palant, A.A.

    2007-01-01

    Investigation results are discussed on the process of pelletizing with the use of various binders (water, syrup, sulfite-alcoholic residue and bentonite) for flotation sulfide molybdenite concentrate (∼84 % MoS 2 ) of the Mongolian deposit. It is established that with the use of syrup rather strong pellets (>300 g/p) of desired size (2-3 mm) can be obtained at a binder flowrate of 1 kg per 100 kg of concentrate. The main advantage of using syrup instead of bentonite lies in the fact that in this instance no depletion of a molybdenum calcine obtained by oxidizing roasting of raw ore takes place due to syrup complete burning out. This affects positively subsequent hydrometallurgical conversion because of decreasing molybdenum losses with waste cakes [ru

  16. Modulated structure calculated for superconducting hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Arnab; Tse, John S.; Yao, Yansun [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK (Canada)

    2017-09-11

    Compression of hydrogen sulfide using first principles metadynamics and molecular dynamics calculations revealed a modulated structure with high proton mobility which exhibits a diffraction pattern matching well with experiment. The structure consists of a sublattice of rectangular meandering SH{sup -} chains and molecular-like H{sub 3}S{sup +} stacked alternately in tetragonal and cubic slabs forming a long-period modulation. The novel structure offers a new perspective on the possible origin of the superconductivity at very high temperatures in which the conducting electrons in the SH chains are perturbed by the fluxional motions of the H{sub 3}S resulting in strong electron-phonon coupling. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Mechanism of hydrodenitrogenation on phosphides and sulfides.

    Science.gov (United States)

    Oyama, S Ted; Lee, Yong-Kul

    2005-02-17

    The mechanism of hydrodenitrogenation (HDN) of 2-methylpiperidine was studied over a silica-supported nickel phosphide catalyst (Ni2P/SiO2, Ni/P = 1/2) and a commercial Ni-Mo-S/Al2O3 catalyst in a three-phase trickle-bed reactor operated at 3.1 MPa and 450-600 K. Analysis of the product distribution as a function of contact time indicated that the reaction proceeded in both cases predominantly by a substitution mechanism, with a smaller contribution of an elimination mechanism. Fourier transform infrared spectroscopy (FTIR) of the 2-methylpiperidine indicated that at reaction conditions a piperidinium ion intermediate was formed on both the sulfide and the phosphide. It is concluded that the mechanism of HDN on nickel phosphide is very similar to that on sulfides. The mechanism on the nickel phosphide was also probed by comparing the reactivity of piperidine and several of its derivatives in the presence of 3000 ppm S. The relative elimination rates depended on the structure of the molecules, and followed the sequence: 4-methylpiperidine approximately piperidine > 3-methylpiperidine > 2,6-dimethylpiperidine > 2-methylpiperidine. [Chemical structure: see text] This order of reactivity was not dependent on the number of alpha-H or beta-H atoms in the molecules, ruling out their reaction through a single, simple mechanism. It is likely that the unhindered piperidine molecules reacted by an S(N)2 substitution process and the more hindered 2,6-dimethylpiperidine reacted by an E2 elimination process.

  18. New cyclic sulfides, garlicnins I2, M, N, and O, from Allium sativum.

    Science.gov (United States)

    Nohara, Toshihiro; Ono, Masateru; Nishioka, Naho; Masuda, Fuka; Fujiwara, Yukio; Ikeda, Tsuyoshi; Nakano, Daisuke; Kinjo, Junei

    2018-01-01

    One atypical thiolane-type sulfide, garlicnin I 2 (1), two 3,4-dimethylthiolane-type sulfides, garlicnins M (2) and N (3), and one thiabicyclic-type sulfide, garlicnin O (4), were isolated from the acetone extracts of Chinese garlic bulbs, Allium sativum and their structures were characterized. Hypothetical pathways for the production of the respective sulfides were discussed.

  19. Optimization of the superconducting phase of hydrogen sulfide

    Science.gov (United States)

    Degtyarenko, N. N.; Masur, E. A.

    2015-12-01

    The electron and phonon spectra, as well as the densities of electron and phonon states of the SH3 phase and the stable orthorhombic structure of hydrogen sulfide SH2, are calculated for the pressure interval 100-225 GPa. It is found that the I4/ mmm phase can be responsible for the superconducting properties of metallic hydrogen sulfide along with the SH3 phase. Sequential stages for obtaining and conservation of the SH2 phase are proposed. The properties of two (SH2 and SH3) superconducting phases of hydrogen sulfide are compared.

  20. Process for scavenging hydrogen sulfide from hydrocarbon gases

    International Nuclear Information System (INIS)

    Fox, I.

    1981-01-01

    A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe 2 O 3 containing a crystalline phase of Fe 2 O 3 , Fe 3 O 4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected

  1. Sulfidization of an aluminocobaltomolybdenum catalyst using the 35S radioisotope

    International Nuclear Information System (INIS)

    Isagulyants, G.V.; Greish, A.A.; Kogan, V.M.

    1987-01-01

    It has been established that in aluminocobaltomolybdenum catalyst sulfidized with elemental sulfur there are two types of sulfur, free and bound. The maximum amount of bound sulfur in ACM catalyst is 6.6 wt. %, which corresponds to practically complete sulfidation of the ACM catalyst. In the presence of hydrogen an equilibrium distribution of bound sulfur is achieved in a granule of ACM catalyst irrespective of the temperature of sulfidation. In a nitrogen atmosphere it is primarily the surface layers of the catalyst that are sulfured

  2. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO

    1991-01-01

    per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated...... that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the sulfide zone....

  3. Thermoelectric properties of non-stoichiometric lanthanum sulfides

    International Nuclear Information System (INIS)

    Shapiro, E.; Danielson, L.R.

    1983-01-01

    The lanthanum sulfides are promising candidate materials for high-efficiency thermoelectric applications at temperatures up to 1300 0 C. The nonstoichiometric lanthanum sulfides (LaS /SUB x/ , where 1.33 2 //rho/ can be chosen. The thermal conductivity remains approximately constant with stoichiometry, so a material with an optimum value of α 2 //rho/ should possess the optimum figure-of-merit. Data for the Seebeck coefficient and electrical resistivity of non-stoichiometric lanthanum sulfides is presented, together with structural properties of these materials

  4. Denitrifying sulfide removal process on high-salinity wastewaters.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Chaocheng; Wang, Aijie; Guo, Yadong; Lee, Duu-Jong

    2015-08-01

    Denitrifying sulfide removal (DSR) process comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide, and acetate into nitrogen gas, elemental sulfur (S(0)), and carbon dioxide, respectively. Sulfide- and nitrate-laden wastewaters at 2-35 g/L NaCl were treated by DSR process. A C/N ratio of 3:1 was proposed to maintain high S(0) conversion rate. The granular sludge with a compact structure and smooth outer surface was formed. The microbial communities of DSR consortium via high-throughput sequencing method suggested that salinity shifts the predominating heterotrophic denitrifiers at 10 g/L NaCl.

  5. Use of sulfide-containing liquors for removing mercury from flue gases

    Science.gov (United States)

    Nolan, Paul S.; Downs, William; Bailey, Ralph T.; Vecci, Stanley J.

    2006-05-02

    A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.

  6. Remediation of Sulfidic Wastewater by Aeration in the Presence of Ultrasonic Vibration

    Directory of Open Access Journals (Sweden)

    F. Ahmad

    2018-06-01

    Full Text Available In the current study, the aerial oxidation of sodium sulfide in the presence of ultrasonic vibration is investigated. Sulfide analysis was carried out by the methylene blue method. Sodium sulfide is oxidized to elemental sulfur in the presence of ultrasonic vibration. The influence of air flow rate, initial sodium sulfide concentration and ultrasonic vibration intensity on the oxidation of sodium sulfide was investigated. The rate law equation regarding the oxidation of sulfide was determined from the experimental data. The order of reaction with respect to sulfide and oxygen was found to be 0.36 and 0.67 respectively. The overall reaction followed nearly first order kinetics.

  7. Volatility Properties of Polonium

    International Nuclear Information System (INIS)

    Eichler, B.

    2002-06-01

    Thermodynamical constants to describe evaporation processes of polonium are summarized and critically discussed. Additionally, systematic changes of the properties of the chalcogenes are analyzed, empirical correlations are proofed and cyclic processes are balanced. Accordingly, the existing values of entropies for polonium are acceptable. Questionable, however, are those values of enthalpies, which have been deduced from results of the experimental investigations of the vapor pressure temperature dependency, of the melting point, and of the boiling temperatures. Technical difficulties and possible error sources of the measurements resulting from the radioactive decay properties of 210 Po are discussed. Using extrapolative standard enthalpies and entropies as well as their temperature dependency, the equilibrium partial pressure of the monomeric and dimeric polonium above the pure condensed phase and the equilibrium constant of the dimerization reaction in the gas phase are calculated: log p/pa Po (g) = (11.797 ± 0.024) -(9883.4 ± 9.5)/T (for T = 298-600 K); = (10.661 ± 0.057) - (9328.4 ± 4.9)/T (for T = 500-1300 K); log p/pa Po 2 (g) = (13.698 ± 0.049) - (8592.3 ± 19.6)/T (for T = 298-600 K); = (11.424 ± 0.124) - (7584.1 ± 98.1)/T (for T = 500-1300 K); log K (dim) = (-4.895 ± 0.012) + (11071 ± 6)/T. According to these calculations and in contrast to other works, polonium evaporates in the entire temperature range between 298 and 1300 K in the dimeric state. Hence, 'latent heats' of the volatilization processes are clearly larger compared to literature data. Especially in the temperature range of the solid polonium the calculated vapor pressure curve shifts significantly to lower values, whereas the boiling point was almost reproduced by the calculation. The results of the extrapolation for the standard enthalpy of the gaseous monomeric polonium and the dimerization enthalpy ΔH 0 298 Po (g) = 188.9 kJ/mol and ΔH 0 298 (form) Po 2 (g) = 211.5 kJ/mol are

  8. ANALYSE AV SAMVARIASJON MELLOM MÅLT ARBEIDSBELASTNING (NAS) OG DEN SUBJEKTIVE OPPLEVELSEN AV ARBEIDSBELASTNINGEN (NASA-TLX) VED INTENSIVAVDELINGER

    OpenAIRE

    Graarud, Vibeke

    2015-01-01

    SAMMENDRAG Sykehus generelt og intensivavdelinger spesielt er under økende press for å kunne drive god og riktig ressursforvaltning. Dermed øker også behov for å kunne dokumentere intensiv-avdelingenes aktivitet og ressursbehov. Nursing Activities Score (NAS) blir ved flere av landets intensivavdelinger brukt som scoringsverktøy for arbeidsbelastning. Det er et verktøy som har til hensikt å kartlegge behovet for antall sykepleiere per pasient. Det er i Norge flere sykepleiere per intensivpasi...

  9. Å LESE MEDIETEKSTER PÅ IPADEN. Observasjoner av en medievant fireårings bruk av iPad i hjemmet

    Directory of Open Access Journals (Sweden)

    Henriette Jæger

    2016-06-01

    Full Text Available Artikkelen tar utgangspunkt i tre observasjoner av en gutt på fire år som bruker iPad på fritiden. Den søker å synliggjøre de strategiene dette barnet velger for å skaffe seg tilgang til ulike medietekster, hvordan han leser og tolker dem, og den undersøker eventuelle spor av kritisk refleksjon hos barnet over disse tekstene. Teoretisk sett hviler den på en forståelse av mediekompetanse som en parallell prosess til utvikling av lese- og skrivekyndighet (literacy, og medieopplevelsene omtales som viktige møter med tekst. Artikkelen undersøker hvordan å lese medietekster kan legge et grunnlag for å utvikle en utvidet tekstkompetanse eller mediekompetanse. Konklusjonen legger vekt på motivasjon og lekenhet som barns primære inngang til medietekstene og som et grunnlag for å utvikle mediekompetanse (media literacy. The article is based on three observations of a four-year-old boy who uses the iPad in his spare time. It demonstrates the strategies that this boy applies to gain access to various media texts, and how he reads and interprets them. It also seeks to examine traces of critical reflection that he may demonstrate in relation to these texts. Theoretically, it rests on an understanding of media literacy as a parallel process to the development of literacy, and it seeks to demonstrate how reading media texts can create an important starting point for the development of media literacy. The Kindergarten practitioner’s role and opportunities to develop children's media literacy within a kindergarten context is a focus towards the end of the article. In conclusion, I argue that motivation and playfulness are important approaches to media texts and create an important foundation for the development of media literacy

  10. Har forhold under svangerskapet betydning for utviklingen av otitis media?

    Directory of Open Access Journals (Sweden)

    Kari J. Kværner

    2009-10-01

    Full Text Available  SAMMENDRAGMed utgangspunkt i data fra et populasjonsbasert utvalg av 7 992 norske tvillinger ble sammenhengenmellom gjentatte ørebetennelser og forhold under svangerskapet studert. Som parametre på intrauterinevekstforhold ble informasjon om fødselsvekt og gestasjonsalder fra Medisinsk Fødselsregister benyttet.Informasjon om rapporterte øreinfeksjoner ble basert på spørreskjemaer som ble besvart av tvillingene ialderen 18–25 år. Først studerte vi individuelle effekter av fødselsvekt og gestasjonsalder på forekomsten avotitis media (OM. Rapportert fødselsvekt hos individer med OM var signifikant lavere enn hos kontrollene,med en gjennomsnittsforskjell på 86 gram. Hos de som rapporterte OM var gjennomsnittlig gestasjonsalder3 dager kortere enn i kontrollmaterialet. Deretter beregnet vi effekten av fødselsvekt ved bruk av co-twinkontroll metoden. Blant monozygote (MZ tvillingpar gjenspeiler fødselsvektforskjeller innenfor tvillingparetintra-uterine miljøforskjeller. Blant dizygote (DZ par kan vektforskjellen være både genetiske ogmiljøbetinget. Ved sammenligning av fødselsvektforskjeller innenfor tvillingparene er tvillingen som ikkehar gjentatte øreinfeksjoner en matchet kontroll blant OM diskordante par. Resultatene antyder at lavfødselsvekt er en risikofaktor for otitis media. Gjennomsnittlig vektforskjell blant par diskordante for OMvar 48 gram, og den av tvillingen som ikke rapporterte OM hadde signifikant høyere fødselsvekt.Kværner KJ, Tambs K, Harris J, Magnus P. Do pregnancy-related factors influence the development ofotitis media? Nor J Epidemiol 1997; 7 (1: 55-58.  ENGLISH SUMMARYThe association between intrauterine growth, as measured by weight and gestational age, and the occurrenceof recurrent ear infections was studied using data from a population based sample of 7992 Norwegian twins.Perinatal measures were collected from the Medical Birth Registry, and reports of recurrent ear infectionswere based on

  11. Overvåking av norsk kosthold - metoder og resultater

    Directory of Open Access Journals (Sweden)

    Lars Johansson

    2009-11-01

    Full Text Available  SAMMENDRAGKunnskap om endringer i matvarenes sammensetning og befolkningens kosthold er grunnleggende for utformingog oppfølging av en helsefremmende mat- og ernæringspolitikk. Dagens system for overvåking avkostholdet bygger først og fremst på en matvaredatabase og opplysninger om forbruket av matvarer fra tretyper datasett; matforsyningsstatistikk, forbruksundersøkelser og kostholdsundersøkelser. Det avgis årlig envurdering av utviklingen i norsk kosthold i forhold til mat- og ernæringspolitiske målsettinger. Det norskesystemet for overvåking av kostholdet er blitt betydelig styrket i løpet av 1990-årene ved innføringen avregelmessige kostholdsundersøkelser blant landsrepresentative utvalg av befolkningen i ulike aldersgrupperog økte ressurser til analyse av næringsinnholdet i matvarer. Det er imidlertid beskjedent sammenlignet meddatainnsamlingen i land som USA og Storbritannia. Det norske overvåkingssystemet er forsatt i enutviklingsfase, og det må justeres og kompletteres etter hvert. Dessuten vil det arbeides med å kvalitetssikredatainnsamlingen.Johansson L. Surveillance of the diet in Norway – methods and results.Nor J Epidemiol ENGLISH SUMMARYKnowledge about changes in composition and intake of foods, as well as changes in the prevalence of dietrelatedhealth problems is fundamental for an effective food and nutrition policy. The National Council onNutrition and Physical Activity is responsible for evaluating changes in the diet. Annually the Council publishesreports about trends in the Norwegian diet, and suggests measures to improve the diet. The Council, incooperation with the National Food Authority and the Institute for Nutrition Research, University of Oslo,has established a national food and dietary surveillance system. This system is mainly based on a fooddatabase and food consumption data. The food consumption data include three principally different datasets: food supplies, household consumption surveys

  12. Diffusjon av influensa i Norge under spanskesyken 1918-19

    Directory of Open Access Journals (Sweden)

    Svenn-Erik Mamelund

    2009-10-01

    Full Text Available  SAMMENDRAGSpanskesyken var en verdensomspennende influensaepidemi som tok livet av minst 30 millioner mennesker,de fleste i løpet av noen få høstmåneder i 1918, men den strakk seg også inn i 1919. En siste svakbølge fant sted vinteren 1920. De første sporadiske tilfellene av spanskesyken i Norge oppsto i militærleirei begynnelsen av april 1918. Over tre måneder senere kom de første spredte tilfellene av det som skullevise seg å være starten på en ny stor influensapandemi. De første av disse oppsto i Kristiania, mest sannsynligetter smitteimport fra Skottland over Nordsjøen. Sommeren 1918 spredte spanskesyken seg raskt frasør til nord, fra kysten til innlandet innover fjordene, og fra de største byene og industrisentra via mindrebyer og andre tettsteder til landsbygda langs de viktigste ferdselsveiene. Da spanskesyken blusset opp igjenhøsten 1918 spredte den seg langsommere og trolig fra nord til sør, fortsatt fra kysten innover fjordene,men spredning fra byene langs kommunikasjonsveiene var mindre fremtredende. Vinteren 1918/19opptrådte influensaen spredt og sporadisk, tilsynelatende uten bestemt spredningsmønster og rekkefølge.Jernbanen, hurtigruten og automobilrutene spilte trolig en viktig rolle i spredningsprosessen, spesielt andrehalvår 1918. Ulik sosial interaksjon, for eksempel et marked som samlet store folkemengder, kan bidra til åforklare eksplosive utbrudd av influensa og diffusjon på lavt geografisk nivå.Mamelund S-E. The diffusion of influenza in Norway during the 1918-19 Pandemic.Nor J Epidemiol ENGLISH SUMMARYIn 1918-1919, a world-wide pandemic, the Spanish Influenza, swept over the entire globe, killing at least30 million people, most of them during the fall of 1918. A last, but small and less defined wave occurred inthe winter of 1920. The first sporadic cases of Spanish Influenza in Norway are known from army campsin the early days of April 1918. More than three months later, the first scattered

  13. Competitive, microbially-mediated reduction of nitrate with sulfide and aromatic oil components in a low-temperature, western Canadian oil reservoir.

    Science.gov (United States)

    Lambo, Adewale J; Noke, Kim; Larter, Steve R; Voordouw, Gerrit

    2008-12-01

    Fields from which oil is produced by injection of sulfate-bearing water often exhibit an increase in sulfide concentration with time (souring). Nitrate added to the injection water lowers the sulfide concentration by the action of sulfide-oxidizing, nitrate-reducing bacteria (SO-NRB). However, the injected nitrate can also be reduced with oil organics by heterotrophic NRB (hNRB). Aqueous volatile fatty acids (VFAs; a mixture of acetate, propionate, and butyrate) are considered important electron donors in this regard. Injection and produced waters from a western Canadian oil field with a low in situ reservoir temperature (30 degrees C) had only 0.1-0.2 mM VFAs. Amendment of these waters with nitrate gave therefore only partial reduction. More nitrate was reduced when 2% (v/v) oil was added, with light oil giving more reduction than heavy oil. GC-MS analysis of in vitro degraded oils and electron balance considerations indicated that toluene served as the primary electron donor for nitrate reduction. The differences in the extent of nitrate reduction were thus related to the toluene content of the light and heavy oil (30 and 5 mM, respectively). Reduction of nitrate with sulfide by SO-NRB always preceded that with oil organics by hNRB, even though microbially catalyzed kinetics with either electron donor were similar. Inhibition of hNRB by sulfide is responsible for this phenomenon. Injected nitrate will thus initially be reduced with sulfide through the action of SO-NRB. However, once sulfide has been eliminated from the near-injection wellbore region, oil organics will be targeted by the action of hNRB. Hence, despite the kinetic advantage of SO-NRB, the nitrate dose required to eliminate sulfide from a reservoir depends on the concentration of hNRB-degradable oil organics, with toluene being the most important in the field under study. Because the toluene concentration is lower in heavy oilthan in light oil, nitrate injection into a heavy-oil-producing field of

  14. Changes in salivary microbiota increase volatile sulfur compounds production in healthy male subjects with academic-related chronic stress.

    Directory of Open Access Journals (Sweden)

    Bruno Dias Nani

    Full Text Available To investigate the associations among salivary bacteria, oral emanations of volatile sulfur compounds, and academic-related chronic stress in healthy male subjects.Seventy-eight healthy male undergraduate dental students were classified as stressed or not by evaluation of burnout, a syndrome attributed to academic-related chronic stress. This evaluation was carried out using the Maslach Burnout Inventory-Student Survey questionnaire. Oral emanations of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide were measured using an Oral Chroma™ portable gas chromatograph. The amounts in saliva of total bacteria and seven bacteria associated with halitosis were quantified by qPCR. The in vitro production of H2S by S. moorei and/or F. nucleatum was also measured with the Oral Chroma™ instrument.The stressed students group showed increased oral emanations of hydrogen sulfide and dimethyl sulfide, together with higher salivary Solobacterium moorei levels (p < 0.05, Mann Whitney test. There were moderate positive correlations between the following pairs of variables: Fusobacterium nucleatum and S. moorei; F. nucleatum and hydrogen sulfide; Tannerella forsythia and F. nucleatum; T. forsythia and S. moorei. These correlations only occurred for the stressed group (p < 0.05, Spearman correlation. The in vitro experiment demonstrated that S. moorei increased H2S production by F. nucleatum (p < 0.05, ANOVA and Tukey's test.The increased amount of S. moorei in saliva, and its coexistence with F. nucleatum and T. forsythia, seemed to be responsible for increased oral hydrogen sulfide in the healthy male stressed subjects.

  15. IceBridge LVIS POS/AV L1B Corrected Position and Attitude Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge LVIS POS/AV L1B Corrected Position and Attitude Data (IPPLV1B) data set contains georeferencing data from the Applanix 510 and 610 POS AV systems flown...

  16. IceBridge POS/AV L1B Corrected Position and Attitude Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge POS/AV L1B Corrected Position and Attitude (IPAPP1B) data set contains georeferencing data from the Applanix 510 POS AV system flown with the Digital...

  17. KS-LAB Kontroll av hydrometer ASTM 152H : (prosess 14-433 i hb014 og NS8005)

    OpenAIRE

    Nouri, El Hadj

    2007-01-01

    I forbindelse med kvalitetssikring av slemmeanalyser ved bruk av hydrometer har det vist seg å være behov for systematisk kontroll ved innkjøp og bruk av hydrometre. Rapporten beskriver registrerte avvik ved sammenligning av hydrometre og angir hvorledes kontroll av hydrometer skal foregå for å sikre at anvendt utstyr tilfredsstiller gjeldende krav.

  18. Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator

    OpenAIRE

    Dandan Wu; Wenhui Ma; Yingbo Mao; Jiushuai Deng; Shuming Wen

    2017-01-01

    In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The ...

  19. Et studium av samfunnsansvar (CSR) for norske utenlandsetablerte akvakulturselskaper; Marine Harvest og Cermaq Mainstream i Chile

    OpenAIRE

    Sæther, Malin

    2010-01-01

    Oppgaven er et studium av samfunnsansvar for norsk utenlandsetablert akvakulturnæring. Valg av tema er motivert av interessen for den eksisterende samfunnsdebatten omkring næringen og internasjonale næringsstrukturer med fotfeste i utviklingsland. Norsk tilstedeværelse i Chile eksemplifisert ved Marine Harvest og Cermaq Mainstream er anvendt som case studium. Presentasjon og drøfting av Corporate social responsibility (CSR), oversatt til norsk som Selskapers samfunnsansvar, ...

  20. Det afghanska valet i svensk media : En diskursanalys av svensk medias rapportering om parlamentsvalet 2010

    OpenAIRE

    Arvidsson, Jonathan

    2013-01-01

    Den här uppsatsen analyserar svensk medias rapportering om valet i Afghanistan 2010. Med hjälp av metoder framtagna av Van Dijk har en analys av artiklar som berör valet 2010 gjorts. De teoretiska utgångspunkterna är postkolonialism och orientalism. Med hjälp av de perspektiven och Van Dijks medieanalys analyseras materialet för att tydliggöra strukturer i media.

  1. Ungdommers opplevelser med overdreven bruk av online-rollespillet World of Warcraft

    DEFF Research Database (Denmark)

    Flaaten, Øivind; Torp, Steffen; Aarseth, Espen

    2010-01-01

    Ungdommers bruk av online-rollespill blir ofte problematisert (Falkner 2007). På bakgrunn av kvalitative intervjuer med ti ungdommer og fem pårørendekontakter beskrives i denne artikkelen ungdommenes opplevelser av online-spillet World of Warcraft (WoW). Denne pilotstudien gir en nyansert...... for konflikt og hjelpeløshet. Helsefremmende arbeid basert på dialog og tidlig intervensjon kan forhindre at online-spilladferd kommer ut av kontroll....

  2. En obekväm sanning eller en stor bluff? : En analys av den visuella gestaltningen av fenomenet "global uppvärmning" i filmmediet

    OpenAIRE

    Eriksson, Anton; Oretoft, Mikael

    2010-01-01

    En uppsats som kritiskt granskar och analyserar den visuella gestaltningen i två dokumentärfilmer. Huvudtemat i filmerna är global uppvärmning och konsekvenserna av detta. Uppsatsens syfte är att undersöka den visuella gestaltningen av den miljödebatt som filmerna är en del i och genom detta belysa frågor som berör visuell kultur och popularisering av vetenskap.

  3. Testing for Volatility Co-movement in Bivariate Stochastic Volatility Models

    OpenAIRE

    Chen, Jinghui; Kobayashi, Masahito; McAleer, Michael

    2017-01-01

    markdownabstractThe paper considers the problem of volatility co-movement, namely as to whether two financial returns have perfectly correlated common volatility process, in the framework of multivariate stochastic volatility models and proposes a test which checks the volatility co-movement. The proposed test is a stochastic volatility version of the co-movement test proposed by Engle and Susmel (1993), who investigated whether international equity markets have volatility co-movement using t...

  4. Instrument for Airborne Measurement of Carbonyl Sulfide, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop small, low power instrumentation for the real-time direct measurement of carbonyl sulfide (OCS) in the atmosphere, especially...

  5. New sulfide catalysts for the hydroliquefaction of coal

    NARCIS (Netherlands)

    Vissers, J.P.R.; Oers, van E.M.; Beer, de V.H.J.; Prins, R.

    1987-01-01

    Possibilities for the preparation of new metal sulfide catalyst systems based on carbon carriers having favourable textural and surface properties have been explored, and attention has been given to the characterization (structure) and evaluation (hydrosulfurization activity) of these catalysts. Two

  6. Formation of Copper Sulfide Precipitate in Solid Iron

    Science.gov (United States)

    Urata, Kentaro; Kobayashi, Yoshinao

    The growth rate of copper sulfide precipitates has been measured in low carbon steel samples such as Fe-0.3mass%Cu-0.03mass%S-0.1mass%C and Fe-0.1mass%Cu-0.01mass%S- 0.1mass%C. Heat-treatment of the samples was conducted at 1273, 1423 and 1573 K for 100 s - 14.4 ks for precipitation of copper sulfides and then the samples were observed by a scanning electron microscope and a transmission electron microscope to measure the diameter of copper sulfides precipitated in the samples. The growth rate of copper sulfide has been found to be well described by the Ostwald growth model, as follows: R\

  7. Optimization of biological sulfide removal in a CSTR bioreactor.

    Science.gov (United States)

    Roosta, Aliakbar; Jahanmiri, Abdolhossein; Mowla, Dariush; Niazi, Ali; Sotoodeh, Hamidreza

    2012-08-01

    In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.

  8. The price of fixed income market volatility

    CERN Document Server

    Mele, Antonio

    2015-01-01

    Fixed income volatility and equity volatility evolve heterogeneously over time, co-moving disproportionately during periods of global imbalances and each reacting to events of different nature. While the methodology for options-based "model-free" pricing of equity volatility has been known for some time, little is known about analogous methodologies for pricing various fixed income volatilities. This book fills this gap and provides a unified evaluation framework of fixed income volatility while dealing with disparate markets such as interest-rate swaps, government bonds, time-deposits and credit. It develops model-free, forward looking indexes of fixed-income volatility that match different quoting conventions across various markets, and uncovers subtle yet important pitfalls arising from naïve superimpositions of the standard equity volatility methodology when pricing various fixed income volatilities. The ultimate goal of the authors´ efforts is to make interest rate volatility standardization a valuable...

  9. Forbuden frukt smaker best en studie av nordmenns spise- og drikkemønster av sjokolade, søtsaker, salt snacks, sukkerholdige leskedrikker og lignende

    OpenAIRE

    Bugge, Annechen Bahr

    2010-01-01

    Denne studien er en del av forskningsprosjektene Young Food og HealthMeal. Begge prosjektene er finansiert av Norges forskningsråd. Temaet i rapporten er nordmenns spise- og drikkemønster av en type mat og drikke som helsemyndighetene ønsker at befolkningen skal redusere forbruket sitt av – slik som sjokolade, søtsaker, søte bakervarer, salt snacks og sukkerholdige drikker. Selv om forbruksutviklingen de seneste par årene har vist positive tendenser, har altså nordmenn fremdeles et langt høye...

  10. …med andre ord. ”10 stadier i oversettelse av sangtekst”. Oversettelse av Stevie Wonder og Stephen Sondheim til norsk

    OpenAIRE

    Iveland, Kari

    2017-01-01

    Norges musikkhøgskole. Masteroppgave. Utøving med fordypningsemne SAMMENDRAG AV OPPGAVEN --- Denne masteroppgaven er en del av en utøvende master og inneholder en analytisk og en praktisk del. Formålet er å finne en metode, et verktøy, for oversettelse av sangtekst, og å identifisere faktorer i språket som må tas hensyn til i oversettelse. Samlet viser den ulike språklige egenskaper som er med på å prege arbeidet med oversettelser av sangtekster. Med utgangspunkt i teorier om tolknin...

  11. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  12. Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21

    Science.gov (United States)

    Acree, T. E.; Sonoff, Elisabeth P.; Splittstoesser, D. F.

    1971-01-01

    A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO2 per ml is described. The method involves the sparging of H2S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO2 with the analysis. PMID:5111300

  13. Observability of market daily volatility

    Science.gov (United States)

    Petroni, Filippo; Serva, Maurizio

    2016-02-01

    We study the price dynamics of 65 stocks from the Dow Jones Composite Average from 1973 to 2014. We show that it is possible to define a Daily Market Volatility σ(t) which is directly observable from data. This quantity is usually indirectly defined by r(t) = σ(t) ω(t) where the r(t) are the daily returns of the market index and the ω(t) are i.i.d. random variables with vanishing average and unitary variance. The relation r(t) = σ(t) ω(t) alone is unable to give an operative definition of the index volatility, which remains unobservable. On the contrary, we show that using the whole information available in the market, the index volatility can be operatively defined and detected.

  14. Multiscaling and clustering of volatility

    Science.gov (United States)

    Pasquini, Michele; Serva, Maurizio

    1999-07-01

    The dynamics of prices in stock markets has been studied intensively both experimentally (data analysis) and theoretically (models). Nevertheless, while the distribution of returns of the most important indices is known to be a truncated Lévy, the behaviour of volatility correlations is still poorly understood. What is well known is that absolute returns have memory on a long time range, this phenomenon is known in financial literature as clustering of volatility. In this paper we show that volatility correlations are power laws with a non-unique scaling exponent. This kind of multiscale phenomenology is known to be relevant in fully developed turbulence and in disordered systems and it is pointed out here for the first time for a financial series. In our study we consider the New York Stock Exchange (NYSE) daily index, from January 1966 to June 1998, for a total of 8180 working days.

  15. Rettferdige minutter: Fordeling av spilletid i fotballkamper for aldersbestemte klasser

    Directory of Open Access Journals (Sweden)

    Trine Anker

    2010-01-01

    Full Text Available På et fotballag i overgangen mellom barne- og ungdomsfotballen er spilletid på fotballbanen under kamp både en knapp ressurs og en kilde til diskusjoner om fordeling. Spørsmålet som er utgangspunkt for denne artikkelen, er hvilke hensyn som bør tas når trener og lagleder skal fordele samlet spilletid på enkeltspillere. Er det viktigst å vinne fotballkampen, eller har det størst betydning å fordele spilletiden mest mulig likt mellom spillerne? Skal det tas hensyn til guttenes evner, motivasjon og preferanser? Er deres familiebakgrunn og personlighet av betydning? Diskusjonen baserer seg på en gjennomgang av ulike politiske rettferdighetsteorier for fordeling av knappe goder.Nøkkelord: rettferdighet, practice, fordelingsrettferdighet, diskursetikk, idrettsetikkEnglish summary: Minutes of justice: Distribution of time during football matches in a boys' teamDuring a football match, time for playing can be considered as a limited good. In this article the point of departure is the redistribution of time in a boys' football team in the transition phase between children and youth football. The questions are how and under which conditions time for playing should be distributed among the players. Is winning the game more important than trying to let every player play for an equal amount of time? Should the boys' talents, motivation, and preferences be considered while distributing time, or are family background and personality of importance? Different theories of political justice for the distribution of limited goods underpin the discussion of how to distribute the minutes of playing time during a football match.http://dx.doi.org/10.5324/eip.v4i1.1737

  16. Artificial vision support system (AVS(2)) for improved prosthetic vision.

    Science.gov (United States)

    Fink, Wolfgang; Tarbell, Mark A

    2014-11-01

    State-of-the-art and upcoming camera-driven, implanted artificial vision systems provide only tens to hundreds of electrodes, affording only limited visual perception for blind subjects. Therefore, real time image processing is crucial to enhance and optimize this limited perception. Since tens or hundreds of pixels/electrodes allow only for a very crude approximation of the typically megapixel optical resolution of the external camera image feed, the preservation and enhancement of contrast differences and transitions, such as edges, are especially important compared to picture details such as object texture. An Artificial Vision Support System (AVS(2)) is devised that displays the captured video stream in a pixelation conforming to the dimension of the epi-retinal implant electrode array. AVS(2), using efficient image processing modules, modifies the captured video stream in real time, enhancing 'present but hidden' objects to overcome inadequacies or extremes in the camera imagery. As a result, visual prosthesis carriers may now be able to discern such objects in their 'field-of-view', thus enabling mobility in environments that would otherwise be too hazardous to navigate. The image processing modules can be engaged repeatedly in a user-defined order, which is a unique capability. AVS(2) is directly applicable to any artificial vision system that is based on an imaging modality (video, infrared, sound, ultrasound, microwave, radar, etc.) as the first step in the stimulation/processing cascade, such as: retinal implants (i.e. epi-retinal, sub-retinal, suprachoroidal), optic nerve implants, cortical implants, electric tongue stimulators, or tactile stimulators.

  17. Hydrogen sulfide oxidation without oxygen - oxidation products and pathways

    International Nuclear Information System (INIS)

    Fossing, H.

    1992-01-01

    Hydrogen sulfide oxidation was studied in anoxic marine sediments-both in undisturbed sediment cores and in sediment slurries. The turn over of hydrogen sulfide was followed using 35 S-radiolabeled hydrogen sulfide which was injected into the sediment. However, isotope exchange reactions between the reduced sulfur compounds, in particular between elemental sulfur and hydrogen sulfide, influenced on the specific radioactivity of these pools. It was, therefore, not possible to measure the turn over rates of the reduced sulfur pools by the radiotracer technique but merely to use the radioisotope to demonstrate some of the oxidation products. Thiosulfate was one important intermediate in the anoxic oxidation of hydrogen sulfide and was continuously turned over by reduction, oxidation and disproportionation. The author discusses the importance of isotope exchange and also presents the results from experiments in which both 35 S-radiolabeled elemental sulfur, radiolabeled hydrogen sulfide and radiolabeled thiosulfate were used to study the intermediates in the oxidative pathways of the sulfur cycle

  18. Bioavailability and stability of mercury sulfide in Armuchee (USA) soil

    International Nuclear Information System (INIS)

    Han, Fengxiang; Shiyab, Safwan; Su, Yi; Monts, David L.; Waggoner, Charles A.; Matta, Frank B.

    2007-01-01

    Because of the adverse effects of elemental mercury and mercury compounds upon human health, the U.S. Department of Energy (DOE) is engaged in an on-going effort to monitor and remediate mercury-contaminated DOE sites. In order to more cost effectively implement those extensive remediation efforts, it is necessary to obtain an improved understanding of the role that mercury and mercury compounds play in the ecosystem. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide in an Armuchee (eastern US ) soil. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the ecosystem have been examined, as has the dynamics of the dissolution of mercury sulfide by various extractants. The results show that mercury sulfide in contaminated Armuchee soil was still to some extent bioavailable to plants. After planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than pure mercury sulfide reagent. Dissolution kinetics of soil mercury sulfide and pure chemical reagent by nitric acid are different. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. Chelating chemicals increase the solubility and bioavailability of mercury in HgS-contaminated soil. (authors)

  19. Laser cleaning of sulfide scale on compressor impeller blade

    International Nuclear Information System (INIS)

    Tang, Q.H.; Zhou, D.; Wang, Y.L.; Liu, G.F.

    2015-01-01

    Highlights: • The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established. • The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning. • The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization. • It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. - Abstract: Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.

  20. Oil Volatility Risk and Expected Stock Returns

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Pan, Xuhui (Nick)

    After the financialization of commodity futures markets in 2004-05 oil volatility has become a strong predictor of returns and volatility of the overall stock market. Furthermore, stocks' exposure to oil volatility risk now drives the cross-section of expected returns. The difference in average...... return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

  1. Distribution of volatile organic compounds over a semiconductor Industrial Park in Taiwan.

    Science.gov (United States)

    Chiu, Kong-Hwa; Wu, Ben-Zen; Chang, Chih-Chung; Sree, Usha; Lo, Jiunn-Guang

    2005-02-15

    This study examined volatile organic compounds (VOC) concentration in ambient air collected during the years 2000--2003 at several different locations of Hsinchu Science-based Industrial Park (HSIP) in Taiwan. A canister automated GC-MS system analyzed the volatile organics in ambient air grasp samples according to T0-15 method. Oxygenated volatiles were the most abundant VOC detected in HSIP followed by aromatics that are commonly used as solvents in the semiconductor industries. The major components measured in the ambient air are 2-propanol (29-135 ppbv), acetone (12-164 ppbv), benzene (0.7-1.7 ppbv), and toluene (13-20 ppbv). At some of the sampling locations, odorous compounds such as carbon disulfide and dimethyl sulfide levels exceed threshold values. The estimated toluene/benzene ratio is very high at most of the sites. However, the total amount of VOC is reduced over the years from 2000 to 2003 due to strict implementation on use and discharge of solvents in industries. There exists no definite seasonal pattern for sporadic occurrence of high levels of some of the volatile organics. Stagnant weather conditions with low wind speeds aid accumulation of toxic species at ground level. The results entail that hi-tech semiconductor industries are still a potential source for harmful organic substances to surrounding microenvironment.

  2. Analysis of Organic Volatile Flavor Compounds in Fermented Stinky Tofu Using SPME with Different Fiber Coatings

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2012-03-01

    Full Text Available The organic volatile flavor compounds in fermented stinky tofu (FST were studied using SPME-GC/MS. A total of 39 volatile compounds were identified, including nine esters, seven alcohols, five alkenes, four sulfides, three heterocycles, three carboxylic acids, three ketones, two aldehydes, one phenol, one amine and one ether. These compounds were determined by MS, and conformed by comparison of the retention times of the separated constituents with those of authentic samples and by comparison of retention indexes (RIs of separated constituents with the RIs reported in the literature. The predominant volatile compound in FST was indole, followed by dimethyl trisulfide, phenol, dimethyl disulfide and dimethyl tetrasulfide. In order to find a better extraction time, the extraction times was optimized for each type of SPME fiber; the results show that the best extraction time for Carboxen/PDMS is 60 min, for PDMS/DVB 30 min, for DVB/CAR/PDMS 60 min and for PDMS 75 min. Of the four fibers used in this work, Carboxen/PDMS is found to be the most suitable to extract the organic volatile flavor compounds in fermented stinky tofu.

  3. Volatilization from borosilicate glass melts of simulated Savannah River Plant waste

    International Nuclear Information System (INIS)

    Wilds, G.W.

    1979-01-01

    Laboratory scale studies determined the rates at which the semivolatile components sodium, boron, lithium, cesium, and ruthenium volatilized from borosilicate glass melts that contained simulated Savannah River Plant waste sludge. Sodium and boric oxides volatilize as the thermally stable compound sodium metaborate, and accounted for approx. 90% of the semivolatiles that evolved. The amounts of semivolatiles that evolved increased linearly with the logarithm of the sodium content of the glass-forming mixture. Cesium volatility was slightly suppressed when titanium dioxide was added to the melt, but was unaffected when cesium was added to the melt as a cesium-loaded zeolite rather than as a cesium carbonate solution. Volatility of ruthenium was not suppressed when the glass melt was blanketed with a nonoxidizing atmosphere. Trace quantities of mercury were removed from vapor streams by adsorption onto a silver-exchanged zeolite. A bed containing silver in the ionic state removed more than 99.9% of the mercury and had a high chemisorption capacity. Beds of lead-, copper-, and copper sulfide-exchanged zeolite-X and also an unexchanged zeolite-X were tested. None of these latter beds had high removal efficiency and high chemisorption capacity

  4. Volatilization from borosilicate glass melts of simulated Savannah River Plant waste

    International Nuclear Information System (INIS)

    Wilds, G.W.

    1978-01-01

    Laboratory scale studies determined the rates at which the semivolatile components sodium, boron, lithium, cesium, and ruthenium volatilized from borosilicate glass melts that contained simulated Savannah River Plant waste sludge. Sodium and boric oxides volatilize as the thermally stable compound sodium metaborate, and accounted for approx. 90% of the semivolatiles that evolved. The amounts of semivolatiles that evolved increased linearly with the logarithm of the sodium content of the glass-forming mixture. Cesium volatility was slightly suppressed when titanium dioxide was added to the melt, but was unaffected when cesium was added to the melt as a cesium-loaded zeolite rather than as a cesium carbonate solution. Volatility of ruthenium was not suppressed when the glass melt was blanketed with a nonoxidizing atmosphere. Trace quantities of mercury were removed from vapor streams by adsorption onto a silver-exchanged zeolite. A bed containing silver in the ionic state removed more than 99.9% of the mercury and had a high chemisorption capacity. Beds of lead-, copper-, and copper sulfide-exchanged zeolite-X and also an unexchanged zeolite-X were tested. None of these latter beds had high removal efficiency and high chemisorption capacity

  5. Hydrogen sulfide production from subgingival plaque samples.

    Science.gov (United States)

    Basic, A; Dahlén, G

    2015-10-01

    Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95 ± 6.6%). Fifty-six percent had moderate periodontal breakdown (CAL > 3  7 mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p = 0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p = 0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Tillämpning av IAS 40 i onoterade fastighetsbolag

    OpenAIRE

    Wallin, Fredrik; Nilsson, Karolina; Ericsson, Marina

    2006-01-01

    Enligt IAS 40 – Förvaltningsfastigheter, definieras förvaltningsfastigheter som ”mark eller byggnader eller del av byggnad som innehas i syfte att generera hyresinkomster eller värdestegring”. Onoterade fastighetsbolag i Sverige har idag möjlighet att välja mellan att värdera sina fastigheter till anskaffningsvärde eller verkligt värde. IAS – International Accounting Standards är en internationell redovisningsstandard inom EU som började tillämpas i januari 2001, men blev obligatorisk för bör...

  7. EST Table: AV404130 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available n (Reed-Steinberg cell-expressed intermediate filament-associated protein) [Tribolium castaneum] 10/08/28 53...78 aa gnl|Amel|GB30360-PB 10/09/10 54 %/199 aa gi|189241063|ref|XP_967018.2| PREDICTED: similar to restin (Reed-Steinberg cell-expres...sed intermediate filament-associated protein) [Tribolium castaneum] FS906662 pg-- ... ...AV404130 pg--0509 10/09/28 54 %/199 aa ref|XP_967018.2| PREDICTED: similar to resti

  8. Kjønnsforskjeller i forekomst av legemiddelrelaterte bivirkninger

    Directory of Open Access Journals (Sweden)

    Hedvig Nordeng

    2009-11-01

    Full Text Available  SAMMENDRAGKvinnelig kjønn er blitt identifisert som risikofaktor for legemiddelrelaterte bivirkninger både i primærhelsetjenestenog under sykehusopphold. Hyppigere forekomst av bivirkninger kan forklares delvis,men ikke fullstendig, av at kvinner som gruppe konsumerer oftere og flere legemidler. Videre har legemiddelbrukhos kvinner i mange tilfeller tilknytning til biologiske tilstander som menstruasjon, graviditetog menopause, og den øker med alderen. Det er viktig å ta i betraktning kulturelle forskjeller hoskvinner og menn som kan være med på å overestimere kjønnsforskjellene i bivirkningsforekomsten.Kvinner bruker helsevesenet hyppigere og rapporterer oftere bivirkninger. Høyere bivirkningsfrekvenshos kvinner kan også være resultat av at kvinner generelt får høyere dose per kg enn menn fordikvinner veier mindre. Kjønnsforskjeller i bivirkninger kan i tillegg være knyttet til forskjellig aktivitet ileverenzymene cytochrom P450, som metaboliserer de fleste legemidler. Strukturelle og funksjonellekjønnsforskjeller finnes også i nyrer, lunger, hjerte/kar- og mage/tarmsystemet, og påvirker i varierendegrad effekt og sikkerhet av legemidler.Nordeng H. Gender differences in the occurrence of adverse drug events.Nor J Epidemiol ENGLISH SUMMARYBoth pharmacoepidemiological and clinical studies have identified female gender as a risk factor foradverse events of drugs, both in primary care and in a hospital setting. Frequent occurrence of adverseevents can partly, but not totally, be explained by the fact that women as a group consume more drugsthan men. Women’s drug consumption can to a certain degree be related to menstruation, pregnancyand menopause, and increases with age. It is essential to take into account cultural differences that cancontribute to an overestimation of the gender effect of adverse drug events. Women use the health caresystem more frequently and report more often and more willingly adverse events. Higher

  9. Physiological behavior of hydrogen sulfide in rice plant. Part 5. Effect of hydrogen sulfide on respiration of rice roots

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, H; Takagi, S

    1955-01-01

    The inhibitory effects of hydrogen sulfide on the respiration of rice plant roots were investigated using Warburg's manometory technique. Hydrogen sulfide inhibited not only aerobic respiration but anaerobic respiration process of roots. Inhibitory action of hydrogen sulfide and potassium cyanide on the respiration were apparently reversible, but the style of recovery reaction from inhibition was somewhat different in each case. Oxygen consumption of roots was increased by addition of ammonium salts, but the same effects were not recognized by the addition of any other salt examined (except nitrate salts). There was close relationship between respiration of roots and assimilation of nitrogen by roots. The increased oxygen uptake by addition of ammonium salt was also inhibited by hydrogen sulfide. The reactivation of this reaction occurred with the recovery of endogenous respiration of roots. 19 references, 8 figures, 3 tables.

  10. Risk management of Norwegian oil production; Risikostyring av norsk oljeproduksjon

    Energy Technology Data Exchange (ETDEWEB)

    Kloegetvedt, Bjoern

    1998-07-01

    The items discussed in this presentation are: (1) Oil price chronology, (2) Market structure - Forward prices, (3) Volatility in oil prices, (4) Sales strategies and price fixing, (5) Development of ''Risk Management'' in the oil trading, (6) Oil products and markets, (7) Management of risk exposure, (8) Strong points and weak points of the norm price system, (9) Comparison with UK.

  11. DOES ENERGY CONSUMPTION VOLATILITY AFFECT REAL GDP VOLATILITY? AN EMPIRICAL ANALYSIS FOR THE UK

    Directory of Open Access Journals (Sweden)

    Abdul Rashid

    2013-10-01

    Full Text Available This paper empirically examines the relation between energy consumption volatility and unpredictable variations in real gross domestic product (GDP in the UK. Estimating the Markov switching ARCH model we find a significant regime switching in the behavior of both energy consumption and GDP volatility. The results from the Markov regime-switching model show that the variability of energy consumption has a significant role to play in determining the behavior of GDP volatilities. Moreover, the results suggest that the impacts of unpredictable variations in energy consumption on GDP volatility are asymmetric, depending on the intensity of volatility. In particular, we find that while there is no significant contemporaneous relationship between energy consumption volatility and GDP volatility in the first (low-volatility regime, GDP volatility is significantly positively related to the volatility of energy utilization in the second (high-volatility regime.

  12. Thiosulfate leaching of gold from sulfide wastes

    Energy Technology Data Exchange (ETDEWEB)

    Block-Bolten, A.; Torma, A.E.

    1986-07-01

    The kinetics of gold extraction from lead-zinc sulfide flotation tailings by thiosulfate leachants has been investigated. The order of reaction as well as the overall reaction rate constant were, with respect to thiosulfate concentration, calculated to be n=0.75 and k=1.05 x 10/sup -6/ mol/sup 1/4/ dm/sup 5/4/ min/sup -1/. The apparent activation energy was found to be ..delta..E/sub a/=48.53 kJ and the frequency factor A=7.5 x 10/sup 2/ mol dm/sup -3/ min/sup -1/. This activation energy value suggests chemical control of the reaction mechanism. Optimum leach temperature of 50/sup 0/C was established. Gold extractions as high as 99% have been realized in two step countercurrent leachings. Change in pH throughout the leaching process was found to be an excellent indicator for the progress of the extraction. A preliminary economic evaluation of the process is given.

  13. Luminescent sulfides of monovalent and trivalent cations

    International Nuclear Information System (INIS)

    1975-01-01

    The invention discloses a family of luminescent materials or phosphors having a rhombohedral crystal structure and consisting essentially of a mixed host sulfide of at least one monovalent host cation and at least one trivalent host cation, and containing, for each mole of phosphor, 0.0005 to 0.05 mole of at least one activating cation. The monovalent host cations may be Na, K or Rb and Cs. The trivalent host cations may be Gd, La, Lu, Sc and Y. The activating cations may be one or more of trivalent As, Bi, Ce, Dy, Er, Pr, Sb, Sm, Tb and Tm; divalent Lu, Mn, Pb and Sn; and monovalent Ag, Cu and Tl. The novel phosphors may be used in devices to convert electron-beam, ultraviolet or x-ray energy to light in the visible spectrum. Such energy conversion can be employed for example in fluoroscopic screens, and in viewing screens of cathode-ray tubes and other electron tubes

  14. Comparison of Carbon XANES Spectra from an Iron Sulfide from Comet Wild 2 with an Iron Sulfide Interplanetary Dust Particle

    Science.gov (United States)

    Wirick, S.; Flynn, G. J.; Keller, L. P.; Sanford, S. A.; Zolensky, M. E.; Messenger, Nakamura K.; Jacobsen, C.

    2008-01-01

    Among one of the first particles removed from the aerogel collector from the Stardust sample return mission was an approx. 5 micron sized iron sulfide. The majority of the spectra from 5 different sections of this particle suggests the presence of aliphatic compounds. Due to the heat of capture in the aerogel we initially assumed these aliphatic compounds were not cometary but after comparing these results to a heated iron sulfide interplanetary dust particle (IDP) we believe our initial interpretation of these spectra was not correct. It has been suggested that ice coating on iron sulfides leads to aqueous alteration in IDP clusters which can then lead to the formation of complex organic compounds from unprocessed organics in the IDPs similar to unprocessed organics found in comets [1]. Iron sulfides have been demonstrated to not only transform halogenated aliphatic hydrocarbons but also enhance the bonding of rubber to steel [2,3]. Bromfield and Coville (1997) demonstrated using Xray photoelectron spectroscopy that "the surface enhancement of segregated sulfur to the surface of sulfided precipitated iron catalysts facilitates the formation of a low-dimensional structure of extraordinary properties" [4]. It may be that the iron sulfide acts in some way to protect aliphatic compounds from alteration due to heat.

  15. Physiologic AV valvular insufficiency in cine MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yoon Hyung; Kang, Eun Joo; Baik, Seung Kug; Ahn, Woo Hyun; Choi, Han Yong; Kim, Bong Gi [Wallace Memorial Baptist Hospital, Pusan (Korea, Republic of)

    1994-05-15

    To give a help in the interpretation of cardiac cine-MR examination, the extent, shape, and timing of appearance of signal void regions near atrioventricular(A-V) valve prospectively evaluate in the healthy population. Using an axial gradient-echo technique with small flip angle, repetition time(TR) of 36 msec and echo time(TE) of 22 msec, 20 volunteers without known valvular abnormalities undertook cardiac cine-MR imaging including atrioventricular valve areas. Transient signal void was observed within the near the tricuspid(13/20 = 65%) and mitral valves(9/20 = 45%), respectively, which is so called {sup p}hysioloic atrioventricular valvular insufficiency{sup .} Eight subjects revealed the signal void areas near both tricuspid and mitral valves but, 5 subjects did not show any evidence of physiologic insufficiency. This physiologic condition does not extend more than 1 cm proximal to A-V valve plane and is generally observed only during early systole. Its morphology is semilunar or triangular configuration with the base to the valve plane in most cases of normal tricuspid insufficiency and small globular appearance in most cases of normal mitral insufficiency. Awareness of normal signal void areas near the A-V valve and their characteristics is critical in the interpretation of cardiac cine MR examinations and maybe helpful in the study of the normal cardiac physiology.

  16. Physiologic AV valvular insufficiency in cine MR imaging

    International Nuclear Information System (INIS)

    Jang, Yoon Hyung; Kang, Eun Joo; Baik, Seung Kug; Ahn, Woo Hyun; Choi, Han Yong; Kim, Bong Gi

    1994-01-01

    To give a help in the interpretation of cardiac cine-MR examination, the extent, shape, and timing of appearance of signal void regions near atrioventricular(A-V) valve prospectively evaluate in the healthy population. Using an axial gradient-echo technique with small flip angle, repetition time(TR) of 36 msec and echo time(TE) of 22 msec, 20 volunteers without known valvular abnormalities undertook cardiac cine-MR imaging including atrioventricular valve areas. Transient signal void was observed within the near the tricuspid(13/20 = 65%) and mitral valves(9/20 = 45%), respectively, which is so called p hysioloic atrioventricular valvular insufficiency . Eight subjects revealed the signal void areas near both tricuspid and mitral valves but, 5 subjects did not show any evidence of physiologic insufficiency. This physiologic condition does not extend more than 1 cm proximal to A-V valve plane and is generally observed only during early systole. Its morphology is semilunar or triangular configuration with the base to the valve plane in most cases of normal tricuspid insufficiency and small globular appearance in most cases of normal mitral insufficiency. Awareness of normal signal void areas near the A-V valve and their characteristics is critical in the interpretation of cardiac cine MR examinations and maybe helpful in the study of the normal cardiac physiology

  17. UNIPASS for AvSP? A Broader View

    Science.gov (United States)

    Wu, N. Eva

    2001-01-01

    UNIPASS is a general-purpose probabilistic computer program consisting of three major modules, including preprocessor, solver and postprocessor. UNIPASS contains a user-friendly Graphical User Interface (GUI), numerous state-of-the-art probabilistic analysis techniques, a large library of statistical distributions and a function module with a large library of support functions that can easily define any complex limit-state function in a scripting FORTRAN-like syntax format. Its inverse probability analysis and sensitivities analysis capabilities make it a powerful design aid in any product cycle. Its precise numerical analysis engine is accurate enough to push the failure probabilities of a design to well below 10 (exp -50). UNIPASS is equipped with advanced artificial intelligence that is designed to handle systems with an essentially unlimited number of random variables with ease and efficiency. Its modular arrangement allows you to tailor an analysis to the desired level of accuracy and efficiency. The depth and comprehensiveness of UNIPASS are built upon the decades of experience and expertise of industry leaders including Boeing Aircraft, NASA and the DoD. Its rich content also makes UNIPASS a valuable instructional tool for random processes and probabilistic mechanics. The topics include: 1) Reliability in AvSP; 2) Role of UNIPASS in AvSP; and 3) Examples. This paper is in viewgraph form.

  18. Cerebral av angiomas: 3-dimensional demonstration by spiral CT

    International Nuclear Information System (INIS)

    Rieger, J.; Hosten, N.; Neumann, K.; Lemke, A.J.; Langer, R.; Lanksch, W.R.; Pfeifer, K.J.; Felix, R.

    1994-01-01

    In 20 patients with known or suspected supratentorial arteriovenous malformations, an attempt was made to see how far CT angiography with 3-dimensional reconstructions is able to make a diagnosis and to differentiate the various components of the angioma. Spiral CT was performed following an intravenous bolus injection of 60-80 ml of iodine containing contrast medium. In all patients the diagnosis was confirmed by intra-arterial DSA of the vertebral vessels. In 13 patients, av malformations could be diagnosed following multiplanar 3-D reconstructions which agreed with the findings on DSA. The large supplying vessels, the nidus and the large draining veins could be defined with certainty. In 6 patients follow-up examination after embolisation was performed. The results could be demonstrated in three dimensions and the success of treatment could be documented unequivocally. CT angiography with 3-D reconstruction is able to supply important information in the majority of intracranial av malformations, both during initial investigation and following treatment. (orig.) [de

  19. Selvbestemmelse og oppdragelse : en teoretisk analyse av oppdragelsens påvirkning på utviklingen av selvbestemmelse

    OpenAIRE

    Hagen, Marit Svennevig; Haugstvedt, Merete Lehne Rugdal

    2007-01-01

    1) Problemstilling Hensikten med oppgaven er å rette fokus mot oppdragelse som en påvirkningsfaktor på utviklingen av selvbestemmelsen, og hvilken betydning behovstilfredsstillelse har for individets subjektive velvære. Oppdragelse er et populært tema som stadig blir debattert i mediene. Det diskuteres blant annet hvorfor oppdragelse er viktig, hvordan det er mulig å oppdra barn på best mulig måte og hvem som er viktige oppdragere i dagens samfunn. Vår oppgave handler om individets selvbes...

  20. Volatility Spillovers Across Petroleum Markets

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Kočenda, Evžen; Vácha, Lukáš

    2015-01-01

    Roč. 36, č. 3 (2015), s. 309-329 ISSN 0195-6574 R&D Projects: GA ČR GA14-24129S Keywords : Volatility spillovers * Asymmetry * Petroleum markets Subject RIV: AH - Economics Impact factor: 1.662, year: 2015 http://library.utia.cas.cz/separaty/2014/E/barunik-0438407.pdf

  1. Stochastic Volatility and DSGE Models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller

    This paper argues that a specification of stochastic volatility commonly used to analyze the Great Moderation in DSGE models may not be appropriate, because the level of a process with this specification does not have conditional or unconditional moments. This is unfortunate because agents may...

  2. Characterisation of selected volatile organic compounds in ...

    African Journals Online (AJOL)

    GCMS), was used to identify volatile compounds at three different temperatures. Fifty volatile compounds, inclusive of 14 acids, 14 alcohols, and 22 esters were identified and quantified in the two brands of indigenous banana beer samples. Only 12 ...

  3. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  4. A Fractionally Integrated Wishart Stochastic Volatility Model

    NARCIS (Netherlands)

    M. Asai (Manabu); M.J. McAleer (Michael)

    2013-01-01

    textabstractThere has recently been growing interest in modeling and estimating alternative continuous time multivariate stochastic volatility models. We propose a continuous time fractionally integrated Wishart stochastic volatility (FIWSV) process. We derive the conditional Laplace transform of

  5. Cost Linkages Transmit Volatility Across Markets

    DEFF Research Database (Denmark)

    Nguyen, Daniel Xuyen; Schaur, Georg

    We present and test a model relating a firm's idiosyncratic cost, its exporting status, and the volatilities of its domestic and export sales. In prior models of trade, supply costs for domestic and exports were linear and thus additively separable. We introduce a nonlinear cost function in order...... to link the domestic and export supply costs. This theoretical contribution has two new implications for the exporting firm. First, the demand volatility in the foreign market now directly affects the firm's domestic sales volatility. Second, firms hedge domestic demand volatility with exports. The model...... has several testable predictions. First, larger firms have lower total and domestic sales volatilities. Second, foreign market volatility increases domestic sales volatilities for exporters. Third, exporters allocate output across both markets in order to reduce total sales volatility. We find...

  6. Fluctuation behaviors of financial return volatility duration

    Science.gov (United States)

    Niu, Hongli; Wang, Jun; Lu, Yunfan

    2016-04-01

    It is of significantly crucial to understand the return volatility of financial markets because it helps to quantify the investment risk, optimize the portfolio, and provide a key input of option pricing models. The characteristics of isolated high volatility events above certain threshold in price fluctuations and the distributions of return intervals between these events arouse great interest in financial research. In the present work, we introduce a new concept of daily return volatility duration, which is defined as the shortest passage time when the future volatility intensity is above or below the current volatility intensity (without predefining a threshold). The statistical properties of the daily return volatility durations for seven representative stock indices from the world financial markets are investigated. Some useful and interesting empirical results of these volatility duration series about the probability distributions, memory effects and multifractal properties are obtained. These results also show that the proposed stock volatility series analysis is a meaningful and beneficial trial.

  7. Volatile organic compound emissions from Larrea tridentata (creosotebush

    Directory of Open Access Journals (Sweden)

    A. Guenther

    2010-12-01

    Full Text Available We present results from the CREosote ATmosphere Interactions through Volatile Emissions (CREATIVE 2009 field study in southern Arizona aimed at quantifying emission rates of VOCs from creosotebush (Larrea tridentata during the summer 2009 monsoon season. This species was chosen because of its vast distribution in North and South American deserts and because its resins have been reported to contain a rich set of volatile organic compounds (VOC. While a variety of ecosystems have been investigated for VOC emissions, deserts remain essentially unstudied, partially because of their low biomass densities and water limitations. However, during the North American monsoon, a pronounced increase in rainfall from an extremely dry June (80 mm occurs over large areas of the Sonoran desert in the southwestern United States and northwestern Mexico. We observed a strong diurnal pattern of branch emissions and ambient concentrations of an extensive suite of VOCs with maxima in early afternoon. These include VOCs typically observed in forest sites (oxygenated VOCs and volatile isoprenoids as well as a large number of other compounds, some of which have not been previously described from any plant including 1-chloro-2-methoxy-benzene and isobutyronitrile. Although generally considered to be derived from anthropogenic sources, we observed emissions of aromatic compounds including benzene, and a broad range of phenolics. Dimethyl sulfide emissions from creosotebush were higher than reported from any previously studied plant suggesting that terrestrial ecosystems should be reconsidered as an important source of this climatically important gas. We also present direct, primary emission measurements of isoprene and its apparent oxidation products methyl vinyl ketone, methacrolein, and 3-methyl furan (the later three compounds are typically assumed to form from secondary reactions within the atmosphere, as well as a group of compounds considered to be fatty acid

  8. Adsorption of sulfide ions on cerussite surfaces and implications for flotation

    International Nuclear Information System (INIS)

    Feng, Qicheng; Wen, Shuming; Zhao, Wenjuan; Deng, Jiushuai; Xian, Yongjun

    2016-01-01

    Highlights: • A new discussion on the lead sulfide species is introduced. • The Na_2S concentration determines cerussite sulfidization. • The activity of lead sulfide species also determines cerussite sulfidization. • Disulfide and polysulfide in lead sulfide species affect its activity. - Abstract: The adsorption of sulfide ions on cerussite surfaces and implications for flotation were studied by X-ray photoelectron spectroscopy (XPS) analysis, micro-flotation tests, and surface adsorption experiments. The XPS analysis results indicated that lead sulfide species formed on the mineral surface after treatment by Na_2S, and the increase in the Na_2S concentration was beneficial for sulfidization. In addition to the content of lead sulfide species, its activity, which was determined by the proportion of sulfide, disulfide and polysulfide, also played an important role in cerussite sulfidization. Micro-flotation tests results demonstrated that insufficient or excessive addition of Na_2S in pulp solutions has detrimental effects on flotation performance, which was attributed to the dosage of Na_2S and the activity of lead sulfide species formed on the mineral surface. Surface adsorption experiments of sulfide ions determined the residual S concentrations in pulp solutions and provided a quantitative illustration for the inhibition of cerussite flotation by excessive sulfide ions. Moreover, it also revealed that sulfide ions in the pulp solution were transformed onto the mineral surface and formed lead sulfide species. These results showed that both of lead sulfide species and its activity acted as an important role in sulfidization flotation process of cerussite.

  9. Adsorption of sulfide ions on cerussite surfaces and implications for flotation

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Qicheng [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Wen, Shuming, E-mail: fqckmust@126.com [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Zhao, Wenjuan [Kunming Metallurgical Research Institute, Kunming 650031 (China); Deng, Jiushuai; Xian, Yongjun [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2016-01-01

    Highlights: • A new discussion on the lead sulfide species is introduced. • The Na{sub 2}S concentration determines cerussite sulfidization. • The activity of lead sulfide species also determines cerussite sulfidization. • Disulfide and polysulfide in lead sulfide species affect its activity. - Abstract: The adsorption of sulfide ions on cerussite surfaces and implications for flotation were studied by X-ray photoelectron spectroscopy (XPS) analysis, micro-flotation tests, and surface adsorption experiments. The XPS analysis results indicated that lead sulfide species formed on the mineral surface after treatment by Na{sub 2}S, and the increase in the Na{sub 2}S concentration was beneficial for sulfidization. In addition to the content of lead sulfide species, its activity, which was determined by the proportion of sulfide, disulfide and polysulfide, also played an important role in cerussite sulfidization. Micro-flotation tests results demonstrated that insufficient or excessive addition of Na{sub 2}S in pulp solutions has detrimental effects on flotation performance, which was attributed to the dosage of Na{sub 2}S and the activity of lead sulfide species formed on the mineral surface. Surface adsorption experiments of sulfide ions determined the residual S concentrations in pulp solutions and provided a quantitative illustration for the inhibition of cerussite flotation by excessive sulfide ions. Moreover, it also revealed that sulfide ions in the pulp solution were transformed onto the mineral surface and formed lead sulfide species. These results showed that both of lead sulfide species and its activity acted as an important role in sulfidization flotation process of cerussite.

  10. Pyrolysis and volatilization of cocaine

    International Nuclear Information System (INIS)

    Martin, B.R.; Lue, L.P.; Boni, J.P.

    1989-01-01

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

  11. Chemical and colloidal aspects of collectorless flotation behavior of sulfide and non-sulfide minerals.

    Science.gov (United States)

    Aghazadeh, Sajjad; Mousavinezhad, Seyed Kamal; Gharabaghi, Mahdi

    2015-11-01

    Flotation has been widely used for separation of valuable minerals from gangues based on their surface characterizations and differences in hydrophobicity on mineral surfaces. As hydrophobicity of minerals widely differs from each other, their separation by flotation will become easier. Collectors are chemical materials which are supposed to make selectively valuable minerals hydrophobic. In addition, there are some minerals which based on their surface and structural features are intrinsically hydrophobic. However, their hydrophobicities are not strong enough to be floatable in the flotation cell without collectors such as sulfide minerals, coal, stibnite, and so forth. To float these minerals in a flotation cell, their hydrophobicity should be increased in specific conditions. Various parameters including pH, Eh, size distribution, mill types, mineral types, ore characterization, and type of reaction in flotation cells affect the hydrophobicity of minerals. Surface analysis results show that when sulfide minerals experience specific flotation conditions, the reactions on the surface of these minerals increase the amount of sulfur on the surface. These phenomenons improve the hydrophobicity of these minerals due to strong hydrophobic feature of sulfurs. Collectorless flotation reduces chemical material consumption amount, increases flotation selectivity (grade increases), and affects the equipment quantities; however, it can also have negative effects. Some minerals with poor surface floatability can be increased by adding some ions to the flotation system. Depressing undesirable minerals in flotation is another application of collectorless flotation.

  12. Silver sulfide nanoparticle assembly obtained by reacting an assembled silver nanoparticle template with hydrogen sulfide gas.

    Science.gov (United States)

    Chen, Rui; Nuhfer, Noel T; Moussa, Laura; Morris, Hannah R; Whitmore, Paul M

    2008-11-12

    A fast, simple procedure is described for obtaining an assembly of silver sulfide nanoparticles (Ag(2)S NPs) on a glass substrate through reaction of a template of an assembled layer of silver nanoparticles (Ag NPs) with hydrogen sulfide (H(2)S) gas. The Ag NP template was prepared by assembling a monolayer of spherical Ag NPs (mean diameter of 7.4 nm) on a polyethylenimine-treated glass substrate. Exposure to pure H(2)S for 10 min converted the Ag NPs of the template to Ag(2)S NPs. The resulting Ag(2)S NP assembly, which retains the template nanostructure and particle distribution, was characterized by optical absorption spectroscopy, atomic force microscopy, transmission electron microscopy (TEM), scanning high resolution TEM, energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The Ag(2)S NPs have a crystal structure of monoclinic acanthite, and while they retained the spherical shape of the original Ag NPs, their mean particle size increased to 8.4 nm due to changes to the crystal structure when the Ag NPs are converted into Ag(2)S NPs. The measured optical absorption edge of the Ag(2)S NP assembly indicated an indirect interband transition with a band gap energy of 1.71 eV. The Ag(2)S NP assembly absorbed light with wavelengths below 725 nm, and the absorbance increased monotonically toward the UV region.

  13. Quantification of selected volatile organic compounds in human urine by gas chromatography selective reagent ionization time of flight mass spectrometry (GC-SRI-TOF-MS) coupled with head-space solid-phase microextraction (HS-SPME).

    Science.gov (United States)

    Mochalski, Paweł; Unterkofler, Karl

    2016-08-07

    Selective reagent ionization time of flight mass spectrometry with NO(+) as the reagent ion (SRI-TOF-MS(NO(+))) in conjunction with gas chromatography (GC) and head-space solid-phase microextraction (HS-SPME) was used to determine selected volatile organic compounds in human urine. A total of 16 volatiles exhibiting high incidence rates were quantified in the urine of 19 healthy volunteers. Amongst them there were ten ketones (acetone, 2-butanone, 3-methyl-2-butanone, 2-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, and 4-heptanone), three volatile sulphur compounds (dimethyl sulfide, allyl methyl sulfide, and methyl propyl sulfide), and three heterocyclic compounds (furan, 2-methylfuran, 3-methylfuran). The concentrations of the species under study varied between 0.55 nmol L(-1) (0.05 nmol mmol(-1)creatinine) for allyl methyl sulfide and 11.6 μmol L(-1) (1.54 μmol mmol(-1)creatinine) for acetone considering medians. Limits of detection (LODs) ranged from 0.08 nmol L(-1) for allyl methyl sulfide to 1.0 nmol L(-1) for acetone and furan (with RSDs ranging from 5 to 9%). The presented experimental setup assists both real-time and GC analyses of volatile organic compounds, which can be performed consecutively using the same analytical system. Such an approach supports the novel concept of hybrid volatolomics, an approach which combines VOC profiles obtained from two or more body fluids to improve and complement the chemical information on the physiological status of an individual.

  14. A nonparametric approach to forecasting realized volatility

    OpenAIRE

    Adam Clements; Ralf Becker

    2009-01-01

    A well developed literature exists in relation to modeling and forecasting asset return volatility. Much of this relate to the development of time series models of volatility. This paper proposes an alternative method for forecasting volatility that does not involve such a model. Under this approach a forecast is a weighted average of historical volatility. The greatest weight is given to periods that exhibit the most similar market conditions to the time at which the forecast is being formed...

  15. Testing for Volatility Co-movement in Bivariate Stochastic Volatility Models

    NARCIS (Netherlands)

    J. Chen (Jinghui); M. Kobayashi (Masahito); M.J. McAleer (Michael)

    2017-01-01

    markdownabstractThe paper considers the problem of volatility co-movement, namely as to whether two financial returns have perfectly correlated common volatility process, in the framework of multivariate stochastic volatility models and proposes a test which checks the volatility co-movement. The

  16. Activation mechanism of ammonium ions on sulfidation of malachite (-201) surface by DFT study

    Science.gov (United States)

    Wu, Dandan; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming

    2017-07-01

    The activation mechanism of ammonium ions on the sulfidation of malachite (-201) was determined by density functional theory (DFT) calculations. Results of DFT calculations indicated that interlayer sulfidation occurs during the sulfidation process of malachite (-201). The absorption of both the ammonium ion and sulfide ion on the malachite (-201) surface is stronger than that of sulfur ion. After sulfidation was activated with ammonium ion, the Cu 3d orbital peak is closer to the Fermi level and characterized by a stronger peak value. Therefore, the addition of ammonium ions activated the sulfidation of malachite (-201), thereby improving the flotation performance.

  17. Oil Volatility Risk and Expected Stock Returns

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Pan, Xuhui (Nick)

    return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

  18. Dynamic Factor Models for the Volatility Surface

    DEFF Research Database (Denmark)

    van der Wel, Michel; Ozturk, Sait R.; Dijk, Dick van

    The implied volatility surface is the collection of volatilities implied by option contracts for different strike prices and time-to-maturity. We study factor models to capture the dynamics of this three-dimensional implied volatility surface. Three model types are considered to examine desirable...

  19. Determinants of exchange rate volatility: the case of the new EU members

    Czech Academy of Sciences Publication Activity Database

    Stančík, Juraj

    2007-01-01

    Roč. 57, 9-10 (2007), s. 414-432 ISSN 0015-1920 R&D Projects: GA MŠk LC542 Grant - others:GA ČR(CZ) GA402/06/1293 Program:GA Institutional research plan: CEZ:AV0Z70850503 Keywords : exchange - rate volatility * TARCH model * EMU integration Subject RIV: AH - Economics Impact factor: 0.382, year: 2007 http://journal.fsv.cuni.cz/storage/1085_fau_9_10_2007_00000002.pdf

  20. Long-range dependence in returns and volatility of Central European Stock Indices

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav

    2010-01-01

    Roč. 17, č. 27 (2010), s. 50-67 ISSN 1212-074X R&D Projects: GA ČR GD402/09/H045; GA ČR GA402/09/0965 Grant - others:GA UK(CZ) 5183/2010 Institutional research plan: CEZ:AV0Z10750506 Keywords : long-range dependence * bootstrapping * rescaled range analysis * rescaled variance analysis Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2010/E/kristoufek-long-range dependence in returns and volatility of central european stock indices bces.pdf

  1. Cuprous sulfide as a film insulation for superconductors

    International Nuclear Information System (INIS)

    Wagner, G.R.; Uphoff, J.H.; Vecchio, P.D.

    1982-01-01

    The LCP test coil utilizes a conductor of forced-flow design having 486 strands of multifilametary Nb 3 Sn compacted in a stainless steel sheath. The impetus for the work reported here stemmed from the need for some form of insulation for those strands to prevent sintering during reaction and to reduce ac losses. The work reported here experimented with cuprous sulfide coatings at various coating rates and thicknesses. Two solenoids that were wound with cuprous sulfide-coated wires and heat-treated at 700 degrees C were found to demonstrate that the film is effective in providing turn-to-turn insulation for less than about 0.5V between turns. The sulfide layer provided a metal-semiconductor junction which became conducting at roughly 0.5V. Repeated cycling of the coil voltage in excess of that value produced no damage to the sulfide layer. The junction provided self-protection for the coil as long as the upper allowable current density in the sulfide was not exceeded. No training was apparent up to 6.4 T

  2. Sulfide Species Optical Monitoring by a Miniaturized Silicon Photomultiplier

    Directory of Open Access Journals (Sweden)

    Salvatore Petralia

    2018-02-01

    Full Text Available The monitoring of water-soluble pollutants is receiving a growing interest from the scientific community. In this context, sulfide anion species S2− and HS− are particularly relevant since they can cause acute and chronic toxicity including neurological effects and at high concentrations, even death. In this study, a new strategy for fast and sensitive optical detection of sulfide species in water samples is described. The method uses an integrated silicon photomultiplier (SiPM device coupled with the appropriate analytical strategy applied in a plastic microchip with dried reagents on board. More specifically, all sulfide species (H2S, HS− and S2− in water samples are detected by the fluorescence signal emitted upon the reaction with N,N-dimethyl-phenylenediamine sulfate in the presence of Fe3+, leading to the formation of the fluorescent methylene blue (MB species. It has been proven that the system herein proposed is able to measure sulfide concentration in a linear range from 0–10 mg L−1 with a sensitivity value of about 6.7 µA mg−1 L and a detection limit of 0.5 mg L−1. A comparison with conventional UV-Vis detection method has been also carried out. Data show a very good linear correlation (R2 = 0.98093, proving the effectiveness of the method. Results pave the way toward the development of portable and low-cost device systems for water-soluble sulfide pollutants.

  3. O tornar-se avó no processo de individuação

    Directory of Open Access Journals (Sweden)

    Caroline Dal Ri Kipper

    Full Text Available O tornar-se avó assinala um período de transição no ciclo de vida familiar, marcado por transformações psíquicas significativas para os avós, caracterizando a quarta individuação. Este trabalho teve como objetivo investigar a experiência de tornar-se avó e sua importância no processo de individuação. Foi utilizado delineamento de estudo de caso coletivo. Onze avós maternas, com idades entre 49 e 66 anos, cujas filhas tiveram seu primeiro filho, responderam a uma entrevista semi-estruturada. Todas as avós tinham tido seus primeiros netos e a entrevista referia-se a sua experiência como avós desses netos. Os dados mostraram que o ser avó é uma fonte de renovação e renascimento. O estudo propiciou que as participantes refletissem sobre seus diferentes papéis familiares: avó, mãe, neta e filha. Os dados sugerem que tornar-se avó possibilita que antigos conflitos sejam repensados, renovando antigos vínculos e desejos, o que permite que a avó dê mais um passo rumo à sua individuação.

  4. Money growth volatility and the demand for money in Germany: Friedman's volatility hypothesis revisited

    OpenAIRE

    Brüggemann, Imke; Nautz, Dieter

    1997-01-01

    Recently, the Bundesbank claimed that monetary targeting has become considerably more diffcult by the increased volatility of short-term money growth. The present paper investigates the impact of German money growth volatility on income velocity and money demand in view of Friedman's money growth volatility hypothesis. Granger-causality tests provide some evidence for a velocity-volatility linkage. However the estimation of volatility-augmented money demand functions reveals that - in contras...

  5. American AV: Edgar Dale and the Information Age Classroom.

    Science.gov (United States)

    Acland, Charles R

    2017-01-01

    This article demonstrates how the influential scholar Edgar Dale, alongside a generation of educational technologists, helped build an essential place for AV materials and pedagogical methods in the American classroom. It also shows that, for decades, the Payne Fund philanthropy supported multimedia research agendas that shaped ideas about teaching and technology, far beyond involvement in their famed studies on motion pictures and children in the 1930s. With his writings and research programs, Dale advanced concepts of media experience and systematicity, which came to be understood as common sense to the information society. In so doing he was a leading contributor to the discursive and ideological structure of our age of technological and informational abundance.

  6. EST Table: AV399395 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available AV399395 NV120168 10/09/28 100 %/139 aa ref|NP_001037386.1| glyceraldehyde-3-phosph...ate dehydrogenase [Bombyx mori] gb|ABA43638.2| glyceraldehyde-3-phosphate dehydrogenase [Bombyx mori] 10/08/28 81 %/139...id:CAA88697.1 10/09/10 89 %/142 aa AGAP009623-PA Protein|3R:37154051:37155049:1|gene:AGAP009623 10/09/10 79 %/139... aa gnl|Amel|GB14798-PA 10/09/10 84 %/139 aa gi|91088023|ref|XP_974181.1| PREDICTED: similar to glyceraldehyde 3-phosphate dehydrogenase [Tribolium castaneum] DN237090 NV12 ...

  7. Finansiering av investeringar i immateriella tillgångar

    OpenAIRE

    Voltaire, Christian; Gillebrink, Valerie

    2008-01-01

    Vid en bedömning av ett kreditärende ser banken till projektets företagsekonomiska förutsättningar. För företag som har immateriella tillgångar som de viktigaste tillgångarna i sin redovisning kan det uppstå problem när de ansöker om kredit hos banker. Detta beror på att immateriella tillgångar inte fungerar på samma sätt som materiella och därigenom tillbringar vag säkerhet för en beviljad kredit. Syftet med denna uppsats är att söka finna vad det är som krävs för att ett tjänsteföretag ska ...

  8. UTVÄRDERING AV UTVALDA SD-WAN PRODUKTER

    OpenAIRE

    Åkerblom, Jacob

    2016-01-01

    Denna jämförelsestudie ämnar att undersöka marknadens leverantörer av nätverksutrustning de- finierade som Software Defined Wide Area Networks(SD-WAN). SD-WAN är en innovativ teknik som applicerar virtualisering och Software defined networking koncept i Wide Area Networks (WAN) för att skapa kostnadseffektiva nätverk. Studien har utförts på företaget Curitiba som idag arbetar med konsulttjänster inom utvalda WAN-optimering och SD-WAN-produkter. Arbetets syfte är att utvärdera SD-WAN-lösningar...

  9. Verksamhetsanalys, Planering och Utveckling av en webbtjänst

    OpenAIRE

    Kindstedt, Tomas

    2013-01-01

    Arbetet behandlar utvecklingsprocessen av programmet SECTMA, ett cirkeltränings-program designat för människor som utövar kampsporter. Programmet är designat för alla konditionsnivåer från toppidrottare till de som endast vill förbättra sin kondition. Arbetet är tudelat, i den första delen går jag igenom teori för STOF och Agile för att skapa en grund och en förståelse för hur jag vill utveckla programmet. Den andra delen följer med utvecklingsprocessen stegvis. STOF erbjuder ett ramverk...

  10. Identification of the algal dimethyl sulfide-releasing enzyme: A missing link in the marine sulfur cycle

    Science.gov (United States)

    Alcolombri, Uria; Ben-Dor, Shifra; Feldmesser, Ester; Levin, Yishai; Tawfik, Dan S.; Vardi, Assaf

    2015-06-01

    Algal blooms produce large amounts of dimethyl sulfide (DMS), a volatile with a diverse signaling role in marine food webs that is emitted to the atmosphere, where it can affect cloud formation. The algal enzymes responsible for forming DMS from dimethylsulfoniopropionate (DMSP) remain unidentified despite their critical role in the global sulfur cycle. We identified and characterized Alma1, a DMSP lyase from the bloom-forming algae Emiliania huxleyi. Alma1 is a tetrameric, redox-sensitive enzyme of the aspartate racemase superfamily. Recombinant Alma1 exhibits biochemical features identical to the DMSP lyase in E. huxleyi, and DMS released by various E. huxleyi isolates correlates with their Alma1 levels. Sequence homology searches suggest that Alma1 represents a gene family present in major, globally distributed phytoplankton taxa and in other marine organisms.

  11. Impact of microorganism on polonium volatilization

    International Nuclear Information System (INIS)

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

    2007-01-01

    Volatilization of polonium by microorganisms, Chromobacterium violaceum, Escherichia coli and Bacillus subtilis was examined for pure cultures in LB medium at 30 deg C, showing relative Po emission intensity 100, 10 and 1, respectively. Chromobacterium violaceum pre-cultured in LB medium without Po and suspended in water with Po showed high Po volatilization in spite of poor nutriment condition. Antibiotics inhibit volatilization of Po and cultivation at low temperature greatly reduced volatilization. The results strongly support the biological effects on Po volatilization. (author)

  12. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2−}, NO{sub 3}{sup −}-N, NO{sub 2}{sup −}-N, and Ac{sup −}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup −1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2−}), nitrate (NO{sub 3}{sup −}) and acetate (Ac{sup −}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2−} concentration, S{sup 2−}/NO{sub 3}{sup −}-N ratio and Ac{sup −}-C/NO{sub 3}{sup −}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup −} reduction to NO{sub 2}{sup −}) was inhibited by S{sup 2−} compared with the denitritation step (NO{sub 2}{sup −} reduction to N{sub 2}). Also, the S{sup 2−} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup −} as electron acceptor than that with NO{sub 3}{sup −} as electron acceptor. NO{sub 3}{sup −} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2−}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of

  13. Co-treatment of hydrogen sulfide and methanol in a single-stage biotrickling filter under acidic conditions.

    Science.gov (United States)

    Jin, Yaomin; Veiga, María C; Kennes, Christian

    2007-06-01

    Biofiltration of waste gases is cost-effective and environment-friendly compared to the conventional techniques for treating large flow rates of gas streams with low concentrations of pollutants. Pulp and paper industry off-gases usually contain reduced sulfur compounds, such as hydrogen sulfide and a wide range of volatile organic compounds (VOCs), e.g., methanol. It is desirable to eliminate both of these groups of compounds. Since the co-treatment of inorganic sulfur compounds and VOCs in biotrickling filters is a relatively unexplored area, the simultaneous biotreatment of H2S and methanol as the model VOC was investigated. The results showed that, after adaptation, the elimination capacity of methanol could reach around 236 g m(-3) h(-1) with the simultaneous complete removal (100%) of 12 ppm H2S when the empty bed residence time is 24 s. The pH of the system was around 2. Methanol removal was hardly affected by the presence of hydrogen sulfide, despite the low pH. Conversely, the presence of the VOC in the waste gas reduced the efficiency of H2S biodegradation. The maximal methanol removal decreased somewhat when increasing the gas flow rate. This is the first report on the degradation of methanol at such low pH in a biotrickling filter and on the co-treatment of H2S and VOCs under such conditions.

  14. Volatile constituents of Trichothecium roseum.

    Science.gov (United States)

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

    1978-06-01

    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.

  15. Chirospecific analysis of plant volatiles

    International Nuclear Information System (INIS)

    Tkachev, A V

    2007-01-01

    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.

  16. Chirospecific analysis of plant volatiles

    Energy Technology Data Exchange (ETDEWEB)

    Tkachev, A V [N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-10-31

    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.

  17. Forecasting volatility of crude oil markets

    International Nuclear Information System (INIS)

    Kang, Sang Hoon; Kang, Sang-Mok; Yoon, Seong-Min

    2009-01-01

    This article investigates the efficacy of a volatility model for three crude oil markets - Brent, Dubai, and West Texas Intermediate (WTI) - with regard to its ability to forecast and identify volatility stylized facts, in particular volatility persistence or long memory. In this context, we assess persistence in the volatility of the three crude oil prices using conditional volatility models. The CGARCH and FIGARCH models are better equipped to capture persistence than are the GARCH and IGARCH models. The CGARCH and FIGARCH models also provide superior performance in out-of-sample volatility forecasts. We conclude that the CGARCH and FIGARCH models are useful for modeling and forecasting persistence in the volatility of crude oil prices. (author)

  18. Forecasting volatility of crude oil markets

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang Hoon [Department of Business Administration, Gyeongsang National University, Jinju, 660-701 (Korea); Kang, Sang-Mok; Yoon, Seong-Min [Department of Economics, Pusan National University, Busan, 609-735 (Korea)

    2009-01-15

    This article investigates the efficacy of a volatility model for three crude oil markets - Brent, Dubai, and West Texas Intermediate (WTI) - with regard to its ability to forecast and identify volatility stylized facts, in particular volatility persistence or long memory. In this context, we assess persistence in the volatility of the three crude oil prices using conditional volatility models. The CGARCH and FIGARCH models are better equipped to capture persistence than are the GARCH and IGARCH models. The CGARCH and FIGARCH models also provide superior performance in out-of-sample volatility forecasts. We conclude that the CGARCH and FIGARCH models are useful for modeling and forecasting persistence in the volatility of crude oil prices. (author)

  19. Money, banks and endogenous volatility

    OpenAIRE

    Pere Gomis-Porqueras

    2000-01-01

    In this paper I consider a monetary growth model in which banks provide liquidity, and the government fixes a constant rate of money creation. There are two underlying assets in the economy, money and capital. Money is dominated in rate of return. In contrast to other papers with a larger set of government liabilities, I find a unique equilibrium when agents' risk aversion is moderate. However, indeterminacies and endogenous volatility can be observed when agents are relatively risk averse.

  20. Prevalence of E/A wave fusion and A wave truncation in DDD pacemaker patients with complete AV block under nominal AV intervals.

    Directory of Open Access Journals (Sweden)

    Wolfram C Poller

    Full Text Available Optimization of the AV-interval (AVI in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB under the pre-programmed AVI. We manually optimized sub-optimal AVI.We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129 and under atrial pacing (AV-pace; n = 31. Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a normal, b too long (E/A wave fusion or c too short (A wave truncation. In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography.All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%. In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI: 12.6-26.2%. A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 ± 13.6 ms.Given the rate of 19.4% (CI 12.6-26.2% of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases.

  1. Separation of platinum metals by theirs extraction as sulfides

    International Nuclear Information System (INIS)

    Pilipenko, A.T.; Ryabushko, O.P.; Ty Van Mak

    1978-01-01

    Separation of platinum metals by means of their sediment in the form of sulfides with subsequent extraction is studied. The optimum conditions of metal sulfide extraction are determined, the metal output dependence from acidness and aqueous phase composition and also the organic solvent nature are investigated. Ruthenium concentration was determined photometrically. Ruthenium sulfide is extracted by butyl spirit from 1-4 normal hydrochloric acid. The maximum extraction grade of 63% is reached in 3.2-normal acid. When the mixture of acetic and hydrochloric acids (2:1) is used for decomposition of ruthenium tiosalts, the grade of ruthenium extraction by amyl spirit or the mixture of anyl and butyl spirits (1:1) constitutes 100%

  2. Metal sulfide electrodes and energy storage devices thereof

    Science.gov (United States)

    Chiang, Yet-Ming; Woodford, William Henry; Li, Zheng; Carter, W. Craig

    2017-02-28

    The present invention generally relates to energy storage devices, and to metal sulfide energy storage devices in particular. Some aspects of the invention relate to energy storage devices comprising at least one flowable electrode, wherein the flowable electrode comprises an electroactive metal sulfide material suspended and/or dissolved in a carrier fluid. In some embodiments, the flowable electrode further comprises a plurality of electronically conductive particles suspended and/or dissolved in the carrier fluid, wherein the electronically conductive particles form a percolating conductive network. An energy storage device comprising a flowable electrode comprising a metal sulfide electroactive material and a percolating conductive network may advantageously exhibit, upon reversible cycling, higher energy densities and specific capacities than conventional energy storage devices.

  3. Preparation of transition metal sulfide nanoparticles via hydrothermal route

    International Nuclear Information System (INIS)

    Fei-Ling, P.; Chin-Hua, C.; Sarani Zakaria; Tze-Khong, L.; Mohd Ambar Yarmo; Nay-Ming, H.

    2010-01-01

    Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesised via a simple hydrothermal method. Sodium thiosulfate pentahydrate (Na 2 S 2 O 3 ·5H 2 O) and hydroxylamine sulfate ((H 3 NO) 2 ·H 2 SO 4 ) were used as the starting materials and reacted with the transition metal source at 200 degree Celsius for 90 min. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). Spherical shape CuS and FeS 2 nanoparticles with high crystallinity were successfully produced. The transmission electron micrographs revealed the well-dispersibility of the produced nanoparticles. Scanning electron micrograph showed the MoS 2 nanoparticles possessed a spherical shape with sheet-like structure covering on the outer surface of the particles. (author)

  4. Conspicuous veils formed by vibrioid bacteria on sulfidic marine sediment

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    , but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3- to 2.5- by 4- to 10-µm) cells that multiply by binary division and contain several spherical inclusions of poly......We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients......, forming a cohesive whitish veil at the oxic-anoxic interface. Bacteria attached to the veil kept rotating and adapted their stalk lengths dynamically to changing oxygen concentrations. The joint action of rotating bacteria on the veil induced a homogeneous water flow from the oxic water region toward...

  5. Study of radiation synovectomy using 188Re-sulfide

    International Nuclear Information System (INIS)

    Chen Gang; Li Peiyong; Jiang Xufeng; Zhang Liying; Wang Xuefeng; Sun Zhenming; Zhang Huan

    2002-01-01

    Objective: To study the radiation synovectomy with 188 Re-sulfide. Methods: Thirty cases were divided into 2 groups, the group with hemophilia and the group with rheumatoid arthritis (RA). Patients with joint synovitis were injected different doses of 188 Re-sulfide, 222 - 444 MBq intra-articular. MRI was taken before and 3 - 6 months after the radiation synovectomy to evaluate the treatment efficacy, and the symptoms were also evaluated. Results: MRI study showed that after the treatment the synovium became thiner and the edema was reduced in the lesioned joint. The symptoms were improved with the pain relieved and duration of intra-articular hemorrhage reduced. Conclusions: Radiation synovectomy using 188 Re-sulfide has effects on synovitis. It can be used clinically to improve the symptoms of joint synovitis and reduce the duration of intra-articular hemorrhage

  6. Forecasting volatility for options valuation

    International Nuclear Information System (INIS)

    Belaifa, M.; Morimune, K.

    2006-01-01

    The petroleum sector plays a neuralgic role in the basement of world economies, and market actors (producers, intermediates, as well as consumers) are continuously subjected to the dynamics of unstable oil market. Huge amounts are being invested along the production chain to make one barrel of crude oil available to the end user. Adding to that are the effect of geopolitical dynamics as well as geological risks as expressed in terms of low chances of successful discoveries. In addition, fiscal regimes and regulations, technology and environmental concerns are also among some of the major factors that contribute to the substantial risk in the oil industry and render the market structure vulnerable to crises. The management of these vulnerabilities require modern tools to reduce risk to a certain level, which unfortunately is a non-zero value. The aim of this paper is, therefore, to provide a modern technique to capture the oil price stochastic volatility that can be implemented to value the exposure of an investor, a company, a corporate or a Government. The paper first analyses the regional dependence on oil prices, through a historical perspective and then looks at the evolution of pricing environment since the large price jumps of the 1970s. The main causes of oil prices volatility are treated in the third part of the paper. The rest of the article deals with volatility models and forecasts used in risk management, with an implication for pricing derivatives. (author)

  7. Human skin volatiles: a review.

    Science.gov (United States)

    Dormont, Laurent; Bessière, Jean-Marie; Cohuet, Anna

    2013-05-01

    Odors emitted by human skin are of great interest to biologists in many fields; applications range from forensic studies to diagnostic tools, the design of perfumes and deodorants, and the ecology of blood-sucking insect vectors of human disease. Numerous studies have investigated the chemical composition of skin odors, and various sampling methods have been used for this purpose. The literature shows that the chemical profile of skin volatiles varies greatly among studies, and the use of different sampling procedures is probably responsible for some of these variations. To our knowledge, this is the first review focused on human skin volatile compounds. We detail the different sampling techniques, each with its own set of advantages and disadvantages, which have been used for the collection of skin odors from different parts of the human body. We present the main skin volatile compounds found in these studies, with particular emphasis on the most frequently studied body regions, axillae, hands, and feet. We propose future directions for promising experimental studies on odors from human skin, particularly in relation to the chemical ecology of blood-sucking insects.

  8. Volatilization of gasoline from soil

    International Nuclear Information System (INIS)

    Arthus, P.

    1993-05-01

    Gasoline contaminated soil threatens water resources and air quality. The extent of the threat depends on gasoline behavior in soil, which is affected by various mechanisms such as volatilization. To quantify volatilization, gasoline spills were simulated in the laboratory using a synthetic gasoline and three dry soils. Total gasoline and individual gasoline compound concentrations in soil were monitored as a function of depth and time. The time to reduce overall gasoline concentration in coarse sand, sandy loam, and silt loam to 40% of initial concentration, averaged between surface and a 200-mm depth, ranged from 0.25 d to 10 d. A wicking phenomenon which contributed to gasoline flux toward the atmosphere was indicated by behavior of a low-volatility gasoline compound. Based on separate wicking experiments, this bulk immiscible movement was estimated at an upward velocity of 0.09 m/d for Delhi sandy loam and 0.05 m/d for Elora silt loam. 70 refs., 24 figs., 34 tabs

  9. ELECTROCHEMICAL DETERMINATION OF HYDROGEN SULFIDE AT CARBON NANOTUBE MODIFIED ELECTRODES. (R830900)

    Science.gov (United States)

    Carbon nanotube (CNT) modified glassy carbon electrodes exhibiting a strong and stable electrocatalytic response towards sulfide are described. A substantial (400 mV) decrease in the overvoltage of the sulfide oxidation reaction (compared to ordinary carbon electrodes) is...

  10. Atmospherically Relevant Radicals Derived from the Oxidation of Dimethyl Sulfide.

    Science.gov (United States)

    Mardyukov, Artur; Schreiner, Peter R

    2018-02-20

    The large number and amounts of volatile organosulfur compounds emitted to the atmosphere and the enormous variety of their reactions in various oxidation states make experimental measurements of even a small fraction of them a daunting task. Dimethyl sulfide (DMS) is a product of biological processes involving marine phytoplankton, and it is estimated to account for approximately 60% of the total natural sulfur gases released to the atmosphere. Ocean-emitted DMS has been suggested to play a role in atmospheric aerosol formation and thereby cloud formation. The reaction of ·OH with DMS is known to proceed by two independent channels: abstraction and addition. The oxidation of DMS is believed to be initiated by the reaction with ·OH and NO 3 · radicals, which eventually leads to the formation of sulfuric acid (H 2 SO 4 ) and methanesulfonic acid (CH 3 SO 3 H). The reaction of DMS with NO 3 · appears to proceed exclusively by hydrogen abstraction. The oxidation of DMS consists of a complex sequence of reactions. Depending on the time of the day or altitude, it may take a variety of pathways. In general, however, the oxidation proceeds via chains of radical reactions. Dimethyl sulfoxide (DMSO) has been reported to be a major product of the addition channel. Dimethyl sulfone (DMSO 2 ), SO 2 , CH 3 SO 3 H, and methanesulfinic acid (CH 3 S(O)OH) have been observed as products of further oxidation of DMSO. Understanding the details of DMS oxidation requires in-depth knowledge of the elementary steps of this seemingly simple transformation, which in turn requires a combination of experimental and theoretical methods. The methylthiyl (CH 3 S·), methylsulfinyl (CH 3 SO·), methylsulfonyl (CH 3 SO 2 ·), and methylsulfonyloxyl (CH 3 SO 3 ·) radicals have been postulated as intermediates in the oxidation of DMS. Therefore, studying the chemistry of sulfur-containing free radicals in the laboratory also is the basis for understanding the mechanism of DMS oxidation in the

  11. TIME VARIATION OF AV AND RV FOR TYPE Ia SUPERNOVAE BEHIND INTERSTELLAR DUST

    Science.gov (United States)

    Huang, Xiaosheng; Biederman, M.; Herger, B.; Aldering, G. S.

    2014-01-01

    TIME VARIATION OF AV AND RV FOR TYPE Ia SUPERNOVAE BEHIND NON-UNIFORM INTERSTELLAR DUST ABSTRACT We investigate the time variation of the visual extinction, AV, and the total-to-selective extinction ratio, RV, resulting from interstellar dust in front of an expanding photospheric disk of a type Ia supernova (SN Ia). We simulate interstellar dust clouds according to a power law power spectrum and produce extinction maps that either follow a pseudo-Gaussian distribution or a lognormal distribution. The RV maps are produced through a correlation between AV and RV. With maps of AV and RV generated in each case (pseudo-Gaussian and lognormal), we then compute the effective AV and RV for a SN as its photospheric disk expands behind the dust screen. We find for a small percentage of SNe the AV and RV values can vary by a large factor from day to day in the first 40 days after explosion.

  12. Rommet som den tredje pedagog - En studie av pedagogers forståelse av rommets betydning - med fokus på estetisk virksomhet

    OpenAIRE

    Krokstad, Inger Elisabeth

    2014-01-01

    Masteroppgaven «Rommet som den tredje pedagog i tre Reggio Emilia-inspirerte barnehager. En studie av pedagogers forståelse av rommets betydning –med fokus på estetisk virksomhet» har til hensikt å bidra til økt kunnskap om estetisk virksomhet som er forbundet med Reggio Emilias tanke om rommet som den tredje pedagog. Avhandlingens problemstilling er: Hvilke mønster kan identifiseres i barnehagepedagogens forståelse av rommet som den tredje pedagog-med fokus på estetisk virksomhet? ...

  13. Rehabilitering efter dekompression och diskoperation - framställandet av en fysioterapeutisk patientanvisning : Ett beställningsarbete av Tölö sjukhus

    OpenAIRE

    Nyberg, Jasmina

    2016-01-01

    Examensarbetet är ett praktiskt inriktat examensarbete med fokus på rehabiliteringen efter en dekompressions- och diskoperation. Det är ett beställningsarbete av Tölö sjukhus med syftet att framställa en fysioterapeutisk patientanvisning. Önskemål från uppdragsgivare var att utforma en tydlig patientanvisning för ryggopererade bestående av skriftliga instruktioner angående postoperativ rehabilitering i form av vardagliga aktiviteter, fysisk aktivitet, ryggens viloställningar, vi...

  14. Vad vill kvinnor ha? : En undersökning av en lokaltidnings bilaga i form av ett livsstilsmagasin.

    OpenAIRE

    Heurling, Åsa; Lovisa, Lesse

    2011-01-01

    Folkbladet är en dagstidning i Norrköping med en stark lokal prägel vars prenumeranter till största delen är sportintresserade män. För att försöka bredda sin läsekrets har man sedan 2009 gett ut en tidning kallad Trend, som vänder sig till kvinnor i åldern 20 - 50 år. Denna tidning med lokal prägel, i form av ett livsstilsmagasin för kvinnor, handlar om mode, skönhet, heminredning och resor. Maga- sinet ges ut i fyra nummer per år och delas ut gratis till alla hushåll i Norrköping med omnejd...

  15. Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

    Science.gov (United States)

    Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-07-15

    The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Volatile and non-volatile/semi-volatile compounds and in vitro bioactive properties of Chilean Ulmo (Eucryphia cordifolia Cav.) honey.

    Science.gov (United States)

    Acevedo, Francisca; Torres, Paulina; Oomah, B Dave; de Alencar, Severino Matias; Massarioli, Adna Prado; Martín-Venegas, Raquel; Albarral-Ávila, Vicenta; Burgos-Díaz, César; Ferrer, Ruth; Rubilar, Mónica

    2017-04-01

    Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis. Ulmo honey volatiles consisted of 50 compounds predominated by 20 flavor components. Two of the volatile compounds, lyrame and anethol have never been reported before as honey compounds. The non-volatile/semi-volatile components of Ulmo honey comprised 27 compounds including 13 benzene derivatives accounting 75% of the total peak area. Ulmo honey exhibited weak antioxidant activity but strong antibacterial activity particularly against gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), the main strain involved in wounds and skin infections. At concentrations >0.5%, Ulmo honey reduced Caco-2 cell viability, released lactate dehydrogenase (LDH) and increased reactive oxygen species (ROS) production in a dose dependent manner in the presence of foetal bovine serum (FBS). The wide array of volatile and non-volatile/semi-volatile constituents of Ulmo honey rich in benzene derivatives may partly account for its strong antibacterial and antiproliferative properties important for its therapeutic use. Our results indicate that Ulmo honey can potentially inhibit cancer growth at least partly by modulating oxidative stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Dialogmøte om teknologi for trenging av fisk i merd

    OpenAIRE

    Henriksen, Kristian; Sunde, Leif Magne; Digre, Hanne; Svendsen, Erik; Rundtop, Per; Erikson, Ulf Gøran

    2013-01-01

    SINTEF Fiskeri og havbruk arrangerte den 19. mars 2013, i samarbeid med Fiskeri- og havbruksnæringens forskningsfond (FHF), et dialogmøte med fokus på teknologi for trenging av fisk i merd. Under møtet ble status for gjeldene teknologi og operasjoner for trenging av fisk i merd, samt resultater fra forskningsprosjekter tilknyttet trengeprosessen, presentert. Videre ble det samlet innspill om utfordringer tilknyttet trenging av fisk i produksjons- og ventemerd fra oppdrettsbedrifter, leverandø...

  18. Experimental constraints on gold and silver solubility in iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Pal' yanova, Galina [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Mikhlin, Yuri [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 50/24, Krasnoyarsk, 660036 (Russian Federation); Kokh, Konstantin, E-mail: k.a.kokh@gmail.com [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Siberian Physical–Technical Institute of Tomsk State University, 1, Novosobornaya, Tomsk, 634050 (Russian Federation); Karmanov, Nick [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Seryotkin, Yurii [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation)

    2015-11-15

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au){sub wt} ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag{sub 2}S) to uytenbogaardtite (Ag{sub 3}AuS{sub 2}) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with

  19. A sulfidation-resistant nickel-base alloy

    International Nuclear Information System (INIS)

    Lai, G.Y.

    1989-01-01

    For applications in mildly to moderately sulfidizing environments, stainless steels, Fe-Ni-Cr alloys (e.g., alloys 800 and 330), and more recently Fe-Ni-Cr-Co alloys (e.g., alloy 556) are frequently used for construction of process equipment. However, for many highly sulfidizing environments, few existing commercial alloys have adequate performance. Thus, a new nickel-based alloy containing 27 wt.% Co, 28 wt.% Cr, 4 wt.% Fe, 2.75 wt.% Si, 0.5 wt.% Mn and 0.05 wt.% C (Haynes alloy HR-160) was developed

  20. Komatiites and nickel sulfide ores of the Black Swan area, Yilgarn Craton, Western Australia. 3: Komatiite geochemistry, and implications for ore forming processes

    Science.gov (United States)

    Barnes, Stephen J.; Hill, Robin E. T.; Evans, Noreen J.

    2004-11-01

    absence of sulfide in the assimilant. Contamination signatures in spinifex-textured rocks may be a guide to Ni-sulfide mineralisation, but are not entirely reliable in the absence of other evidence. The widespread vesicularity of the sequence may be attributable to assimilated water rather than to primary mantle-derived volatiles, and cannot be taken as evidence for primary volatile-rich magmas. The characteristic signature of the Black Swan Succession is the presence of highly localised disseminated sulfide within a sequence showing more widespread evidence for crustal contamination and interaction with its immediate substrate. This has important implications for the applicability of trace element geochemistry in exploration for komatiite-hosted nickel deposits.

  1. "Dem vil at barna skal ha noe å gjøre" : En casestudie av Habbo.no

    OpenAIRE

    Kvaale, Torkel

    2012-01-01

    Denne oppgaven er en kvalitativ casestudie av Habbo.no, en virtuell verden der hovedgruppen av brukere er barn og unge. Det kvalitative forskningsintervju representerer metodeverktøyet som er brukt for innsamlingen av data, og datamaterialet består av 10 intervjuer med tilsammen 13 brukere av Habbo.no, i alderen 10-12 år. Habbo ble skapt av det finske selskapet Sulake i 2000 som hevder at denne er verdens største virtuelle verden for tenåringer. Habbo.no er kun én av til sammen 35 unike H...

  2. High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

    Science.gov (United States)

    Hanley, J. J.; Mungall, J. E.

    2004-12-01

    are comparable to and often exceed the economic concentrations of the metals within the ores themselves. As a consequence of these results, current genetic models must be revised to consider the role played by hydrous saline melts and magmatic brines in deposit development, and the potential for interaction and competition between sulfide liquids (or PGE-bearing sulfide minerals) and hydrosaline volatiles for available PGE and Au in a crystallizing mafic igneous system must be critically evaluated.

  3. The solubility of iron sulfides and their role in mass transport in Girdler-Sulfide heavy water plants

    International Nuclear Information System (INIS)

    Tewari, P.H.; Wallace, G.; Campbell, A.B.

    1978-04-01

    The solubilities of several iron sulfides, mackinawite FeSsub((1-x)), troilite FeS, pyrrhotite Fesub((1-x))S (monoclinic and hexagonal), and pyrite FeS 2 have been determined in aqueous H 2 S solution at 0.1 MPa and 1.8 MPa H 2 S pressures between 25 deg and 125 deg C. The dependence of solubility on the pH of the medium has also been studied. It is concluded that since mackinawite is the most soluble of the iron sulfides, and has the highest dissolution rate and the steepest decline in solubility with temperature, its prolonged formation during plant operation should be avoided to minimize iron transport from lower to higher temperature areas in Girdler-Sulfide (G.S.) heavy water plants. This can be achieved by a preconditioning of carbon steel surfaces to convert mackinawite to pyrrhotite and pyrite

  4. Lyden av de mørke sjeler - Lyd og musikk i videospillet Dark Souls

    OpenAIRE

    Burdal, Kristin Johnsrud

    2014-01-01

    Dark Souls er et videospill som skiller seg fra måten de fleste moderne videospill er bygget opp. Lyd og musikk er en viktig del av dette, og i denne oppgava har vi sett på hvordan lyd og musikk brukes i videospillet. Målet var å finne ut hva lyd og musikk har å si for spillopplevelsen. Dette har vi kommet fram til ved analyse av lyden, og analyse av et utvalg av musikkstykker. For å peke på hvordan lydbruken i Dark Souls skiller seg ut, har vi i tillegg sammenligna det med lydbruken andre vi...

  5. Magnetic hard disks for audio-visual use; AV yo jiki disk baitai

    Energy Technology Data Exchange (ETDEWEB)

    Tei, Y.; Sakaguchi, S.; Uwazumi, H. [Fuji Electric Co. Ltd., Tokyo (Japan)

    1999-11-10

    Computers, consumer, and communications are converging and fusing. The key device in homes in the near future will be an audiovisual hard disk drive (AV-HDD). The reason is that there is no other AV cash memory with high capacity, high speed, and a low price than the HDD. Fuji Electric has early started developing an AV magnetic hard disk, a core-functional element of the AV-HDD, to take the initiative in the market. This paper describes the state of plastic medium development, which is regarded as a next-generation strategic commodity. (author)

  6. Effekt av å benytte sosiale medier i kampanjer for å fremme sunne levevaner

    OpenAIRE

    Strømme, Hilde

    2014-01-01

    Hensikten med denne systematiske oversikten er å svare på spørsmålet: Hva er effekten av å benytte sosiale medier i kampanjer for å påvirke holdninger, kunnskap og atferd knyttet til sunne levevaner? Metode: Systematiske søk ble gjort i 11 bibliografiske baser. Tilleggssøk ble gjort i Google Scholar. Utvelgelse og vurdering av publikasjoner ble gjort av to personer uavhengig av hverandre. Risiko for systematiske feil ble vurdert med sjekklisten til Cochrane Effective Practice and Organisation...

  7. Open-Loop Audio-Visual Stimulation (AVS): A Useful Tool for Management of Insomnia?

    Science.gov (United States)

    Tang, Hsin-Yi Jean; Riegel, Barbara; McCurry, Susan M; Vitiello, Michael V

    2016-03-01

    Audio Visual Stimulation (AVS), a form of neurofeedback, is a non-pharmacological intervention that has been used for both performance enhancement and symptom management. We review the history of AVS, its two sub-types (close- and open-loop), and discuss its clinical implications. We also describe a promising new application of AVS to improve sleep, and potentially decrease pain. AVS research can be traced back to the late 1800s. AVS's efficacy has been demonstrated for both performance enhancement and symptom management. Although AVS is commonly used in clinical settings, there is limited literature evaluating clinical outcomes and mechanisms of action. One of the challenges to AVS research is the lack of standardized terms, which makes systematic review and literature consolidation difficult. Future studies using AVS as an intervention should; (1) use operational definitions that are consistent with the existing literature, such as AVS, Audio-visual Entrainment, or Light and Sound Stimulation, (2) provide a clear rationale for the chosen training frequency modality, (3) use a randomized controlled design, and (4) follow the Consolidated Standards of Reporting Trials and/or related guidelines when disseminating results.

  8. Inventering av Suldalslågen. Produksjonspotensial for sjøvandrende laksefisk

    OpenAIRE

    Foldvik, Anders; Pettersen, Oskar

    2017-01-01

    Foldvik, A. & Pettersen, O. 2017. Inventering av Suldalslågen. Produksjonspotensial for sjøvandrende laksefisk. - NINA Kortrapport 75, 18 s. Reguleringen av Suldalslågen til kraftproduksjon har hatt negative effekter for habitat for laksefisk, blant annet i form av sedimentering og begroing av substratet. Disse prosessene har blitt forsøkt motvirket ved å ha en serie med spyleflommer på over 200 m3/s om høsten. På oppdrag fra Statkraft inverterte NINA oppvekst- og gyteforhold for laks i Su...

  9. Is succession in wet calcareous dune slacks affected by free sulfide?

    NARCIS (Netherlands)

    Adema, EB; van Gemerden, H; Grootjans, AP; Adema, Erwin B.; Grootjans, Ab P.; Rapson, G.

    Consequences of sulfide toxicity on succession in wet calcareous dune slacks were investigated. Sulfide may exert an inhibitory effect on dune slack plants, but several pioneer species exhibit ROL (Radial Oxygen Loss) and thereby protect themselves against free sulfide. Under oxic conditions free

  10. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  11. 76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-11-08

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide; Correction. SUMMARY: The... Administrative Stay of the reporting requirements for hydrogen sulfide. The Office of the Federal Register...

  12. A real support effect on the hydrodeoxygenation of methyl oleate by sulfided NiMo catalysts

    NARCIS (Netherlands)

    Coumans, A.E.; Hensen, E.J.M.

    2017-01-01

    The effect of the support on the catalytic performance of sulfided NiMo in the hydrodeoxygenation of methyl oleate as a model compound for triglyceride upgrading to green diesel was investigated. NiMo sulfides were prepared by impregnation and sulfidation on activated carbon, silica, γ-alumina and

  13. Sulfide-iron interactions in domestic wastewater from a gravity sewer

    NARCIS (Netherlands)

    Nielsen, A.H.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4 mg Fe L-1 and 0-5.1 mg S L-1,

  14. Sulfidation of alumina-supported iron and iron-molybdenum oxide catalysts

    NARCIS (Netherlands)

    Ramselaar, W.L.T.M.; Crajé, M.W.J.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Kraan, van der A.M.

    1990-01-01

    The transition of alumina-supported iron and iron-molybdenum catalysts from the oxidic precursor to the sulfided catalysts was systematically studied by means of in-situ Mössbauer spectroscopy at room temperature. This enabled the adjudgement of various sulfidic phases in the sulfided catalysts. The

  15. Stochastic volatility models and Kelvin waves

    Energy Technology Data Exchange (ETDEWEB)

    Lipton, Alex [Merrill Lynch, Mlfc Main, 2 King Edward Street, London EC1A 1HQ (United Kingdom); Sepp, Artur [Merrill Lynch, 4 World Financial Center, New York, NY 10080 (United States)], E-mail: Alex_Lipton@ml.com, E-mail: Artur_Sepp@ml.com

    2008-08-29

    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.

  16. Stochastic volatility models and Kelvin waves

    Science.gov (United States)

    Lipton, Alex; Sepp, Artur

    2008-08-01

    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.

  17. Stochastic volatility models and Kelvin waves

    International Nuclear Information System (INIS)

    Lipton, Alex; Sepp, Artur

    2008-01-01

    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

  18. Uncertainty of Volatility Estimates from Heston Greeks

    Directory of Open Access Journals (Sweden)

    Oliver Pfante

    2018-01-01

    Full Text Available Volatility is a widely recognized measure of market risk. As volatility is not observed it has to be estimated from market prices, i.e., as the implied volatility from option prices. The volatility index VIX making volatility a tradeable asset in its own right is computed from near- and next-term put and call options on the S&P 500 with more than 23 days and less than 37 days to expiration and non-vanishing bid. In the present paper we quantify the information content of the constituents of the VIX about the volatility of the S&P 500 in terms of the Fisher information matrix. Assuming that observed option prices are centered on the theoretical price provided by Heston's model perturbed by additive Gaussian noise we relate their Fisher information matrix to the Greeks in the Heston model. We find that the prices of options contained in the VIX basket allow for reliable estimates of the volatility of the S&P 500 with negligible uncertainty as long as volatility is large enough. Interestingly, if volatility drops below a critical value of roughly 3%, inferences from option prices become imprecise because Vega, the derivative of a European option w.r.t. volatility, and thereby the Fisher information nearly vanishes.

  19. Red coloration by heat treatment of the coprecipitate of cadmium sulfide and mercury(II) sulfide prepared from the nitrates

    International Nuclear Information System (INIS)

    Nakahara, Fujiya

    1979-01-01

    The effects of starting salts on the color, particle size and crystal structure of mercury-cadmium-sulfide pigments were investigated. The coprecipitate (N-S) of cadmium sulfide and mercury (II) sulfide was prepared by adding sodium sulfide solution to a mixed cadmium-mercury (II) nitrate solution. The coprecipitate (C-S) of cadmium sulfide and mercury (II) sulfide was also prepared from the mixed solution of their chlorides by the same method as described above. The coprecipitated products were heat-treated (calcination or hydrothermal treatment) at 350 0 C for 2 hours and subsequent changes in powder properties of both products were compared from each other. The powder properties of N-S, C-S and their heat-treated products were investigated by spectral reflectance, electron microscopy, X-ray diffraction and specific surface area measurements. Sample (N-C) obtained by the calcination of N-S was brown, indicating no red coloration, but the calcined product (C-C) of C-S developed a red color. Cl - and hot water were found to be effective for the red color development of the pigment. The effectiveness was confirmed by calcining N-S in the presence of NaCl or by treating it hydrothermally. It was found that halides other than NaCl, (e.g., NH 4 Cl, KCl, KBr and KI), were also effective for the color development of the pigment. The red samples are solid solutions with a basically hexagonal CdS structure, and it appears that CdS takes up HgS without any apparent structural changes. The particle size of the red samples are larger than those of the non red samples. (author)

  20. IAS 40 i ljuset av ägarförhållanden : Värdering av förvaltningsfastigheter i börsnoterade respektive statliga bolag

    OpenAIRE

    Klarin, Olof; Sandell, Johan

    2010-01-01

    Sammanfattning: Redovisningen av förvaltningsfastigheter enligt IAS 40 har tidigare beskrivits i ett stort antal olika vetenskapliga alster. Merparten av dessa har dock tittat på börsnoterade bolag men det finns även andra företag som tillämpar IAS-reglerna. En grupp företag som gör det är de bolag som ägs av svenska staten. Ett av målen med IFRS är att skapa jämförbarhet och då bör inte ägarformen ha någon betydelse för redovisning och värdering. Denna studies syfte är därför att skapa insik...