WorldWideScience

Sample records for timing volatiles production

  1. 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...

  2. Monitoring Volatile Organic Compounds (VOCs) in real-time on oil and natural gas production sites

    Science.gov (United States)

    Lupardus, R.; Franklin, S. B.

    2017-12-01

    Oil and Natural Gas (O&NG) development, production, infrastructure, and associated processing activities can be a substantial source of air pollution, yet relevant data and real-time quantification methods are lacking. In the current study, O&NG fugitive emissions of Volatile Organic Compounds (VOCs) were quantified in real-time and used to determine the spatial and temporal windows of exposure for proximate flora and fauna. Eleven O&NG sites on the Pawnee National Grassland in Northeastern Colorado were randomly selected and grouped according to production along with 13 control sites from three geographical locations. At each site, samples were collected 25 m from the wellhead in NE, SE, and W directions. In each direction, two samples were collected with a Gasmet DX4040 gas analyzer every hour from 8:00 am to 2:00 pm (6 hours total), July to October, 2016 (N=864). VOC concentrations generally increased during the 6 hr. day with the exception of N2O and were predominately the result of O&NG production and not vehicle exhaust. Thirteen of 24 VOCs had significantly different levels between production groups, frequently above reference standards and at biologically relevant levels for flora and fauna. The most biologically relevant VOCs, found at concentrations exceeding time weighted average permissible exposure limits (TWA PELs), were benzene and acrolein. Generalized Estimating Equations (GEEs) measured the relative quality of statistical models predicting benzene concentrations on sites. The data not only confirms that O&NG emissions are impacting the region, but also that this influence is present at all sites, including controls. Increased real-time VOC monitoring on O&NG sites is required to identify and contain fugitive emissions and to protect human and environmental health.

  3. 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...

  4. Production Function of Outgassed Volatiles on Mercury: Implications for Polar Volatiles on Mercury and the Moon

    Science.gov (United States)

    Deutsch, A. N.; Head, J. W.

    2018-05-01

    We are interested in the flux of volatiles delivered to the polar regions of Mercury and the Moon through time. We integrate the production functions for volatile delivery from impacts, solar wind, and volcanism, which we focus on initially.

  5. Effect of hydraulic retention time on biohydrogen and volatile fatty acids production during acidogenic digestion of dephenolized olive mill wastewaters

    International Nuclear Information System (INIS)

    Scoma, Alberto; Bertin, Lorenzo; Fava, Fabio

    2013-01-01

    The influence of Hydraulic Retention Time (HRT) on the performances of a recently developed biotechnological anaerobic acidogenic process fed with dephenolized Olive Mill Wastewater (OMW) was investigated. The study was carried out under mesophilic conditions in Packed Bed Biofilm Reactors (PBBRs), filled with ceramic cubes and inoculated with a characterized and acclimated acidogenic microbial consortium. The PBBRs were fed with a HRT of 7, 5, 3 or 1 day, which corresponded to Organic Loading Rates (OLRs) of about 5.5, 7.8, 12.9 and 38.8 g L −1 d −1 , respectively. A significant production of a H 2 -rich biogas was observed when shorter HRTs were applied: in particular, H 2 relative amount and productivity increased from 3% to 32% and from 0.20 to 6.10 dm 3 m −3 h −1 , respectively, by decreasing the HRT from 7 to 1 day. On the contrary, shorter HRTs turned into a lower accumulation of Volatile Fatty Acids (VFAs), whose highest amounts were found with HRTs of 7 and 5 days (about 18.4 and 19.7 g L −1 COD equivalents, respectively). The highest conversion yield of COD into VFAs (36%) was obtained with a HRT of 5 days, when VFAs represented about 78% of the effluent COD. HRT also influenced the composition of the VFA mixture: acetic, propionic and butyric acid were the most prominent VFAs, being their relative amounts higher when PBBRs were operated with shorter HRTs (up to 19, 12 and 42% of the whole mixture, respectively, when HRT was 1 day). -- Highlights: ► HRT affects the acidogenic digestion of dephenolized olive mill wastewater. ► A significant production of bioH 2 can be coupled to that of volatile fatty acids. ► Higher H 2 and lower VFA productions were obtained by shortening the HRT

  6. 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...

  7. Mutual fund volatility timing and management fees

    NARCIS (Netherlands)

    Giambona, E.; Golec, J.

    2009-01-01

    This paper shows that compensation incentives partly drive fund managers’ market volatility timing strategies. Larger incentive management fees lead to less counter-cyclical or more pro-cyclical volatility timing. But fund styles or aggregate fund flows could also account for this relation;

  8. Volatile compounds in meat and meat products

    Directory of Open Access Journals (Sweden)

    Monika KOSOWSKA

    Full Text Available Abstract Meaty flavor is composed of a few hundreds of volatile compounds, only minor part of which are responsible for the characteristic odor. It is developed as a result of multi-directional reactions proceeding between non-volatile precursors contained in raw meat under the influence of temperature. The volatile compounds are generated upon: Maillard reactions, lipid oxidation, interactions between Maillard reaction products and lipid oxidation products as well as upon thiamine degradation. The developed flavor is determined by many factors associated with: raw material (breed, sex, diet and age of animal, conditions and process of slaughter, duration and conditions of meat storage, type of muscle, additives applied and the course of the technological process. The objective of this review article is to draw attention to the issue of volatile compounds characteristic for meat products and factors that affect their synthesis.

  9. The Concentrations of Rumen Fluid Volatile Fatty Acids and Ammonia, and Rumen Microbial Protein Production in Sheep Given Feed During the Day and Night Time

    Science.gov (United States)

    Gumilar, D. A. K. W.; Rianto, E.; Arifin, M.

    2018-02-01

    An experimental study was carried out to investigate the concentrations of volatile (VFA), ammonia and microbial protein production of rumen fluid in sheep given fedd during the day and at night. This study used 12 fat-tailed rams aged 12-18 months and weighed 24,12 ± 25 kg (CV = 10,51%). The rams were fed a complete feed containing 16.64% protein and 68,33% total digestible nutrients (TDN). The rams were allocated into a completely randomised design with 3 treatments and 4 replications. The treatments applied were: T1: day time feeding (6.00 hrs - 18.00 hrs); T2: night time feeding (18.00 hrs - 6.00 hrs); and T3: day and night time feedings (6.00 hrs - 6.00 hrs). The parameters observed were dry matter intake (DMI), rumen VFA concentration, rumen ammonia concentration, rumen rmicrobial protein production and the efficiency of rumen microbial protein production. The results showed that feeding time did not significantly affect (P>0.05) all the parameters observed. Dry matter intake, VFA concentration, ammonia concentration, the microbial protein production of rumen fluid and the efficiency of microbial protein production were 1,073g/d, 49.69 mmol; 4.77 mg N/100 ml, 12,111 g/d and 19.96 g per kg digestible organic matter intake (DOMI), respectively. It is concluded that feeding time did not affect DMI, condition of rumen fluid and rumen microbial protein production in sheep.

  10. 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...

  11. Rapid analytical extraction of volatile fermentation products

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, N B; Flickinger, M C; Tsao, G T

    1979-10-01

    With renewed interest in production of liquid fuels and chemical feedstocks from carbohydrates, numerous authors have utilized gas-liquid chromatography (GC) for quantification of volatile products. Poor separation and short column life will result if residual sugars present in the medium are not separated from the volatile compounds before injection. In our current investigation of 2,3-butanediol production from xylose, we have developed a rapid GC assay for 2,3-butanediol, acetyl methyl carbinol (acetoin), 2,3-butanedione (diacetyl), and ethanol. This method extracts the fermentation products at high pH from residual xylose before injection into the GC. This routine is a modification of the method of Kolfenbach et al. and is more rapid than the method of separation of diacetyl and acetoin from carbohydrates by distillation reported by Gupta et al. Their erroneous reports of yields of 640 mg diacetyl + acetoin/g sugar are 30% higher than the theoretical maximum for Enterobacter cloacae (ATCC 27613) and points out the need for a reliable, accurate assay for these products.

  12. Volatile and non-volatile compounds in green tea affected in harvesting time and their correlation to consumer preference.

    Science.gov (United States)

    Kim, Youngmok; Lee, Kwang-Geun; Kim, Mina K

    2016-10-01

    Current study was designed to find out how tea harvesting time affects the volatile and non-volatile compounds profiles of green tea. In addition, correlation of instrumental volatile and non-volatile compounds analyses to consumer perception were analyzed. Overall, earlier harvested green tea had stronger antioxidant capacity (~61.0%) due to the polyphenolic compounds from catechin (23,164 mg/L), in comparison to later harvested green teas (11,961 mg/L). However, high catechin content in green tea influenced negatively the consumer likings of green tea, due to high bitterness (27.6%) and astringency (13.4%). Volatile compounds drive consumer liking of green tea products were also identified, that included linalool, 2,3-methyl butanal, 2-heptanone, (E,E)-3,5-Octadien-2-one. Finding from current study are useful for green tea industry as it provide the difference in physiochemical properties of green tea harvested at different intervals.

  13. Volatile products controlling Titan's tholins production

    KAUST Repository

    Carrasco, Nathalie

    2012-05-01

    A quantitative agreement between nitrile relative abundances and Titan\\'s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan\\'s atmosphere (Gautier et al. [2011]. Icarus, 213, 625-635). Here we present a complementary study on the same reactor using an in situ diagnostic of the gas phase composition. Various initial N 2/CH 4 gas mixtures (methane varying from 1% to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and the inhibition function for aerosol production. This confirms the suspected role of hydrogen as an inhibitor of heterogeneous organic growth processes, as found in Sciamma-O\\'Brien et al. (Sciamma-O\\'Brien et al. [2010]. Icarus, 209, 704-714). The study of the gas phase organic products is focussed on its evolution with the initial methane amount [CH 4] 0 and its comparison with the aerosol production efficiency. We identify a change in the stationary gas phase composition for intermediate methane amounts: below [CH 4] 0=5%, the gas phase composition is mainly dominated by nitrogen-containing species, whereas hydrocarbons are massively produced for [CH 4] 0>5%. This predominance of N-containing species at lower initial methane amount, compared with the maximum gas-to solid conversion observed in Sciamma-O\\'Brien et al. (2010) for identical methane amounts confirms the central role played by N-containing gas-phase compounds to produce tholins. Moreover, two protonated imines (methanimine CH 2NH and ethanamine CH 3CHNH) are detected in the ion composition in agreement with Titan\\'s INMS measurements, and reinforcing the suspected role of these chemical species on aerosol production. © 2012 Elsevier Inc.

  14. Modeling of Volatility with Non-linear Time Series Model

    OpenAIRE

    Kim Song Yon; Kim Mun Chol

    2013-01-01

    In this paper, non-linear time series models are used to describe volatility in financial time series data. To describe volatility, two of the non-linear time series are combined into form TAR (Threshold Auto-Regressive Model) with AARCH (Asymmetric Auto-Regressive Conditional Heteroskedasticity) error term and its parameter estimation is studied.

  15. Do Time-Varying Covariances, Volatility Comovement and Spillover Matter?

    OpenAIRE

    Lakshmi Balasubramanyan

    2005-01-01

    Financial markets and their respective assets are so intertwined; analyzing any single market in isolation ignores important information. We investigate whether time varying volatility comovement and spillover impact the true variance-covariance matrix under a time-varying correlation set up. Statistically significant volatility spillover and comovement between US, UK and Japan is found. To demonstrate the importance of modelling volatility comovement and spillover, we look at a simple portfo...

  16. A two-stage fixed-bed reactor for direct hydrotreatment of volatiles from the hydropyrolysis of biomass: effect of catalyst temperature, pressure and catalyst ageing time on product characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pindoria, R.V.; Megaritis, A.; Herod, A.A.; Kandiyoti, R. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Chemical Engineering and Chemical Technology

    1998-12-01

    This investigation involved the hydropyrolysis of biomass (eucalyptus globulus) and the immediate catalytic hydrocracking of pyrolytic oils in the second stage of the reactor. The effects of temperature, pressure and the catalyst ageing time on the final product tar have been studied using the catalyst Zeolite H-ZSM5. The catalytically hydrocracked tar/oil products were characterised and compared with the hydropyrolysis product from the first stage of the reactor to determine the effect of catalytic hydrocracking. The carbon deposition on the catalyst has been examined using thermogravimetric analysis. The tar yields after catalytic hydrocracking decreased with increasing pressure and temperature of the cracking stage. The tar yields at 10 bar pressure were greater than those at 40 bar pressure. The fresh zeolite catalyst trapped more than 40% of the product from the hydropyrolysis stage and TGA evidence indicated that this was not as carbon deposition but as volatiles trapped in the zeolite matrix. Reuse of the catalyst resulted in little more uptake of volatiles; however, extended use of the catalyst did not result in increased yields of liquid products but in increased production of light volatiles or gas. The H-ZSM5 catalyst appeared to act as a more active cracking catalyst rather than to promote hydrogenation or deoxygenation of the liquids produced in the hydropyrolysis stage. Characterisation of the liquids by SEC and UV fluorescence indicated that structural changes were relatively minor despite the significant changes in yields of liquids with process conditions. Available reaction routes do not appear to allow specific deoxygenation pathways to predominate without disintegration of parent molecules to lighter volatiles, under the conditions used here. 41 refs., 10 figs., 4 tabs.

  17. Liquid biofuel production from volatile fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Steinbusch, K.J.J.

    2010-03-19

    The production of renewable fuels and chemicals reduces the dependency on fossil fuels and limits the increase of CO2 concentration in the atmosphere only if a sustainable feedstock and an energy efficient process are used. The thesis assesses the possibility to use municipal and industrial waste as biomass feedstock to have little of no competition with food production, and to save greenhouse gasses emissions. Waste is a complex substrate with a diverse composition and high water content. It can be homogenized without losing its initial energy value by anaerobic conversion to volatile fatty acids (VFA). Using VFA gives the opportunity to process cheap and abundantly present biomass residues to a fuel and chemical instead of sugar containing crops or vegetable oil. This thesis describes the feasibility to convert VFA to compounds with a higher energy content using mixed culture fermentations by eliminating of oxygen and/or increasing the carbon and hydrogen content. At high hydrogen pressure, protons and electrons release via the reduction of organic products such as VFA becomes thermodynamically more attractive. Three VFA reduction reactions were studied: hydrogenation to an alcohol with (1) hydrogen and (2) an electrode as electron donor, and (3) by chain elongation with hydrogen and ethanol. Based on concentration, production rate and efficiency, elongation of acetate with hydrogen and/or ethanol was the best technique to convert VFA into a fuel. In a CSTR (Continuous-flow stirred-tank reactor), 10.5 g L{sup -1} caproic acid and 0.48 g L{sup -1} caprylic acid were produced with ethanol and/or hydrogen at a specific MCFA (medium-chain fatty acids) production activity of 2.9 g caproate and 0.09 g caprylate per gram VSS d{sup -1} (volatile suspended solids). The products were selectively removed by calcium precipitation and solvent extraction with ethyl hexanoate and petroleum ether. Microbial characterization revealed that the microbial populations were stable and

  18. Effects of daylight savings time changes on stock market volatility.

    Science.gov (United States)

    Berument, M Hakan; Dogan, Nukhet; Onar, Bahar

    2010-04-01

    The presence of daylight savings time effects on stock returns and on stock volatility was investigated using an EGARCH specification to model the conditional variance. The evidence gathered from the major United States stock markets for the period between 1967 and 2007 did not support the existence of the daylight savings time effect on stock returns or on volatility. Returns on the first business day following daylight savings time changes were not lower nor was the volatility higher, as would be expected if there were an effect.

  19. Radiation-induced volatile hydrocarbon production in platelets

    International Nuclear Information System (INIS)

    Radha, E.; Vaishnav, Y.N.; Kumar, K.S.; Weiss, J.F.

    1989-01-01

    Generation of volatile hydrocarbons (ethane, pentane) as a measure of lipid peroxidation was followed in preparations from platelet-rich plasma irradiated in vitro. The hydrocarbons in the headspace of sealed vials containing irradiated and nonirradiated washed platelets, platelet-rich plasma, or platelet-poor plasma increased with time. The major hydrocarbon, pentane, increased linearly and significantly with increasing log radiation dose, suggesting that reactive oxygen species induced by ionizing radiation result in lipid peroxidation. Measurements of lipid peroxidation products may give an indication of suboptimal quality of stored and/or irradiated platelets

  20. Analysis of the influencing factors of PAEs volatilization from typical plastic products.

    Science.gov (United States)

    Chen, Weidong; Chi, Chenchen; Zhou, Chen; Xia, Meng; Ronda, Cees; Shen, Xueyou

    2018-04-01

    The primary emphasis of this research was to investigate the foundations of phthalate (PAEs) pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalate total content in per unit mass and unit surface area of pollutant sources. Through surveying and evaluating the coefficient of volatile strength of PAEs from typical plastic products, this research carried out reasonable classification of PAEs pollutant sources into three categories and then investigated the relationship amongst the coefficient of volatile strength as well as other environmental factors and the concentration level of total PAEs in indoor air measured in environment chambers. Research obtained phthalate concentration results under different temperature, humidity, the coefficient of volatile strength and the closed time through the chamber experiment. In addition, this study further explored the correlation and ratio of influencing factors that affect the concentration level of total PAEs in environment chambers, including environmental factors, the coefficient of volatile strengths of PAEs and contents of total PAEs in plastic products. The research created an improved database system of phthalate the coefficient of volatile strengths of each type of plastic goods, and tentatively revealed that the volatile patterns of PAEs from different typical plastic goods, finally confirmed that the coefficient of volatile strengths of PAEs is a major factor that affects the indoor air total PAEs concentration, which laid a solid foundation for further establishing the volatile equation of PAEs from plastic products. Copyright © 2017. Published by Elsevier B.V.

  1. Volatility Analysis of Bitcoin Price Time Series

    Directory of Open Access Journals (Sweden)

    Lukáš Pichl

    2017-12-01

    Full Text Available Bitcoin has the largest share in the total capitalization of cryptocurrency markets currently reaching above 70 billion USD. In this work we focus on the price of Bitcoin in terms of standard currencies and their volatility over the last five years. The average day-to-day return throughout this period is 0.328%, amounting in exponential growth from 6 USD to over 4,000 USD per 1 BTC at present. Multi-scale analysis is performed from the level of the tick data, through the 5 min, 1 hour and 1 day scales. Distribution of trading volumes (1 sec, 1 min, 1 hour and 1 day aggregated from the Kraken BTCEUR tick data is provided that shows the artifacts of algorithmic trading (selling transactions with volume peaks distributed at integer multiples of BTC unit. Arbitrage opportunities are studied using the EUR, USD and CNY currencies. Whereas the arbitrage spread for EUR-USD currency pair is found narrow at the order of a percent, at the 1 hour sampling period the arbitrage spread for USD-CNY (and similarly EUR-CNY is found to be more substantial, reaching as high as above 5 percent on rare occasions. The volatility of BTC exchange rates is modeled using the day-to-day distribution of logarithmic return, and the Realized Volatility, sum of the squared logarithmic returns on 5-minute basis. In this work we demonstrate that the Heterogeneous Autoregressive model for Realized Volatility Andersen et al. (2007 applies reasonably well to the BTCUSD dataset. Finally, a feed-forward neural network with 2 hidden layers using 10-day moving window sampling daily return predictors is applied to estimate the next-day logarithmic return. The results show that such an artificial neural network prediction is capable of approximate capture of the actual log return distribution; more sophisticated methods, such as recurrent neural networks and LSTM (Long Short Term Memory techniques from deep learning may be necessary for higher prediction accuracy.

  2. Investment timing under hybrid stochastic and local volatility

    International Nuclear Information System (INIS)

    Kim, Jeong-Hoon; Lee, Min-Ku; Sohn, So Young

    2014-01-01

    Highlights: • The effects of hybrid stochastic volatility on real option prices are studied. • The stochastic volatility consists of a fast mean-reverting component and a CEV type one. • A fast mean-reverting factor lowers real option prices and investment thresholds. • The increase of elasticity raises real option prices and investment thresholds. • The effects of the addition of a slowly varying factor depend upon the project value. - Abstract: We consider an investment timing problem under a real option model where the instantaneous volatility of the project value is given by a combination of a hidden stochastic process and the project value itself. The stochastic volatility part is given by a function of a fast mean-reverting process as well as a slowly varying process and the local volatility part is a power (the elasticity parameter) of the project value itself. The elasticity parameter controls directly the correlation between the project value and the volatility. Knowing that the project value represents the market price of a real asset in many applications and the value of the elasticity parameter depends on the asset, the elasticity parameter should be treated with caution for investment decision problems. Based on the hybrid structure of volatility, we investigate the simultaneous impact of the elasticity and the stochastic volatility on the real option value as well as the investment threshold

  3. Thermodynamic analysis of volatile organometallic fission products

    International Nuclear Information System (INIS)

    Auxier II, J.D.; Hall, H.L.; Cressy, Derek

    2016-01-01

    The ability to perform rapid separations in a post nuclear weapon detonation scenario is an important aspect of national security. In the past, separations of fission products have been performed using solvent extraction, precipitation, etc. The focus of this work is to explore the feasibility of using thermochromatography, a technique largely employed in superheavy element chemistry, to expedite the separation of fission products from fuel components. A series of fission product complexes were synthesized and the thermodynamic parameters were measured using TGA/DSC methods. Once measured, these parameters were used to predict their retention times using thermochromatography. (author)

  4. Production of fungal volatile organic compounds in bedding materials

    Directory of Open Access Journals (Sweden)

    S. LAPPALAINEN

    2008-12-01

    Full Text Available The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO 2 production as indicators. The volatile organic compounds were collected into Tenax resin and analysed by gas chromatography. Several microbial volatile organic compounds (MVOCs, e.g. 1-butanol, 2-hexanone, 2-heptanone, 3-octanone, 1-octen-3-ol and 1-octanol were detected in laboratory experiments; however, these accounted for only 0.08-1.5% of total volatile organic com-pounds (TVOCs. Emission rates of MVOCs were 0.001-0.176 mg/kg of bedding materials per hour. Despite some limitations of the analytical method, certain individual MVOCs, 2-hexanone, 2-hep-tanone and 3-octanone, were also detected in concentrations of less than 4.6 mg/m 3 (0.07-0.31% of TVOC in a horse stable where peat and shavings were used as bedding materials. MVOC emission rate was estimated to be 0.2-2.0 mg/kg ´ h -1 from bedding materials in the stable, being about ten times higher than the rates found in the laboratory experiments. Some compounds, e.g. 3-octanone and 1-octen-3-ol, can be assumed to originate mainly from microbial metabolisms.;

  5. Jumps and stochastic volatility in oil prices: Time series evidence

    International Nuclear Information System (INIS)

    Larsson, Karl; Nossman, Marcus

    2011-01-01

    In this paper we examine the empirical performance of affine jump diffusion models with stochastic volatility in a time series study of crude oil prices. We compare four different models and estimate them using the Markov Chain Monte Carlo method. The support for a stochastic volatility model including jumps in both prices and volatility is strong and the model clearly outperforms the others in terms of a superior fit to data. Our estimation method allows us to obtain a detailed study of oil prices during two periods of extreme market stress included in our sample; the Gulf war and the recent financial crisis. We also address the economic significance of model choice in two option pricing applications. The implied volatilities generated by the different estimated models are compared and we price a real option to develop an oil field. Our findings indicate that model choice can have a material effect on the option values.

  6. The Short-Time Behaviour of VIX Implied Volatilities in a Multifactor Stochastic Volatility Framework

    DEFF Research Database (Denmark)

    Barletta, Andrea; Nicolato, Elisa; Pagliarani, Stefano

    error bounds for VIX futures, options and implied volatilities. In particular, we derive exact asymptotic results for VIX implied volatilities, and their sensitivities, in the joint limit of short time-to-maturity and small log-moneyness. The obtained expansions are explicit, based on elementary...... approximations of equity (SPX) options. However, the generalizations needed to cover the case of VIX options are by no means straightforward as the dynamics of the underlying VIX futures are not explicitly known. To illustrate the accuracy of our technique, we provide numerical implementations for a selection...... functions and they neatly uncover how the VIX skew depends on the specific choice of the volatility and the vol-of-vol processes. Our results are based on perturbation techniques applied to the infinitesimal generator of the underlying process. This methodology has been previously adopted to derive...

  7. Influence of season, harvest time and drying on Java citronella (Cymbopogon winterianus Jowitt volatile oil

    Directory of Open Access Journals (Sweden)

    Arie F. Blank

    Full Text Available Java citronella (Cymbopogon winterianus Jowitt is member of the Poaceae family. Java citronella volatile oil has been reported to be among the volatile oils, showing repellent, antimycotic, and acaricide activities. It has been known that agronomical factors have a great effect on both the quality and quantity of essential metabolites. For this reason, it is necessary to determine optimum levels of agronomical factors affecting plant growth and production. Harvest time and drying are very important agronomical factors. This study has been conducted in the Research farm of the " Universidade Federal de Sergipe" , Agronomical Engineering Department along 2002-2003 on the base of factorial experiment in randomized complete block design with three replications. Java citronella was cultivated in a 60 x 60 cm space. Early, midday, and late harvest at 9:00 h, 12:00 h, and 15:00 h were conducted on four different seasons. Fresh and dried leaves were used on the experiments. In order to study the effects of harvest time and drying, yields of dry and fresh herbage (kg/ha, moisture content (%, volatile oil content (% and yield (L/ha, and chemical composition of the volatile oil were measured. Seasonal changes had significant effect on yield of fresh herbage, yield and volatile oil content. Maximum volatile oil yields were observed at 9:00 during summer, winter, and spring. Volatile oil content was influenced by season and drying, but not influenced by harvest time.

  8. Exact probability distribution function for the volatility of cumulative production

    Science.gov (United States)

    Zadourian, Rubina; Klümper, Andreas

    2018-04-01

    In this paper we study the volatility and its probability distribution function for the cumulative production based on the experience curve hypothesis. This work presents a generalization of the study of volatility in Lafond et al. (2017), which addressed the effects of normally distributed noise in the production process. Due to its wide applicability in industrial and technological activities we present here the mathematical foundation for an arbitrary distribution function of the process, which we expect will pave the future research on forecasting of the production process.

  9. Nonparametric volatility density estimation for discrete time models

    NARCIS (Netherlands)

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

    2005-01-01

    We consider discrete time models for asset prices with a stationary volatility process. We aim at estimating the multivariate density of this process at a set of consecutive time instants. A Fourier-type deconvolution kernel density estimator based on the logarithm of the squared process is proposed

  10. Multivariate time-varying volatility modeling using probabilistic fuzzy systems

    NARCIS (Netherlands)

    Basturk, N.; Almeida, R.J.; Golan, R.; Kaymak, U.

    2016-01-01

    Methods to accurately analyze financial risk have drawn considerable attention in financial institutions. One difficulty in financial risk analysis is the fact that banks and other financial institutions invest in several assets which show time-varying volatilities and hence time-varying financial

  11. Contamination of Optical Surfaces Under Irradiation by Outgassed Volatile Products

    International Nuclear Information System (INIS)

    Khasanshin, R. H.; Grigorevskiy, A. V.; Galygin, A. N.; Alexandrov, N. G.

    2009-01-01

    Deposition of outgassed products of a polymeric composite on model material surfaces being irradiated by electrons and protons with initial energies of E e = 40 keV and E p = 30 keV respectively was studied. It was shown that deposition of volatile products on model material surfaces being under ionizing radiations results in increase of organic film growth rate.

  12. Production of volatile organic compounds by cyanobacteria Synechococcus sp.

    Science.gov (United States)

    Hiraiwa, M.; Abe, M.; Hashimoto, S.

    2014-12-01

    Phytoplankton are known to produce volatile organic compounds (VOCs), which contribute to environmental problems such as global warming and decomposition of stratospheric ozone. For example, picophytoplankton, such as Prochlorococcus and Synechococcus, are distributed in freshwater and oceans worldwide, accounting for a large proportion of biomass and primary production in the open ocean. However, to date, little is known about the production of VOCs by picophytoplankton. In this study, VOCs production by cyanobacteria Synechococcus sp. (NIES-981) was investigated. Synechococcus sp. was obtained from the National Institute for Environmental Studies (NIES), Japan, and cultured at 24°C in autoclaved f/2-Si medium under 54 ± 3 µE m-2 s-1 (1 E = 1 mol of photons) with a 12-h light and 12-h dark cycle. VOCs concentrations were determined using a purge-and-trap gas chromatograph-mass spectrometer (Agilent 5973). The concentrations of chlorophyll a (Chl a) were also determined using a fluorometer (Turner TD-700). Bromomethane (CH3Br) and isoprene were produced by Synechococcus sp. Isoprene production was similar to those of other phytoplankton species reported earlier. Isoprene was produced when Chl a was increasing in the early stage of the incubation period (5-15 days of incubation time, exponential phase), but CH3Br was produced when Chl a was reduced in the late stage of the incubation period (30-40 days of incubation time, death phase).

  13. Light Quality Dependent Changes in Morphology, Antioxidant Capacity, and Volatile Production in Sweet Basil (Ocimum basilicum).

    Science.gov (United States)

    Carvalho, Sofia D; Schwieterman, Michael L; Abrahan, Carolina E; Colquhoun, Thomas A; Folta, Kevin M

    2016-01-01

    Narrow-bandwidth light treatments may be used to manipulate plant growth, development and metabolism. In this report LED-based light treatments were used to affect yield and metabolic content of sweet basil (Ocimum basilicum L. cv "Ceasar") grown in controlled environments. This culinary herb produces an aroma highly appreciated by consumers, primarily composed of terpenes/terpenoids, phenylpropanoids, and fatty-acid- derived volatile molecules. Basil plants were grown under narrow-bandwidth light conditions, and leaf area, height, mass, antioxidant capacity and volatile emissions were measured at various time points. The results indicate reproducible significant differences in specific volatiles, and in biochemical classes of volatiles, compared to greenhouse grown plants. For example, basil plants grown under blue/red/yellow or blue/red/green wavelengths emit higher levels of a subset of monoterpenoid volatiles, while a blue/red/far-red treatment leads to higher levels of most sesquiterpenoid volatile molecules. Specific light treatments increase volatile content, mass, and antioxidant capacity. The results show that narrow-bandwidth illumination can induce discrete suites of volatile classes that affect sensory quality in commercial herbs, and may be a useful tool in improving commercial production.

  14. Separation of volatile products from solid carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    White, W W

    1915-10-19

    A process is set forth for the separation of volatile products from solid carbonaceous materials, in which the vapors produced from the carbonaceous material at higher temperatures and withdrawn into the separate vapor chamber are led in succession through the lower temperature vapors as continuously to deposit their condensible ingredients in the chamber by the action of the successive cooler vapors.

  15. Production of fungal volatile organic compounds in bedding materials

    OpenAIRE

    S. LAPPALAINEN; A. PASANEN; P. PASANEN

    2008-01-01

    The high relative humidity of the air and many potential growth media, such as bedding materials, hay and grains in the horse stable, for example, provide suitable conditions for fungal growth. Metabolic activity of four common agricultural fungi incubated in peat and wood shavings at 25°C and 4°C was characterized in this study using previously specified volatile metabolites of micro-organisms and CO 2 production as indicators. The volatile organic compounds were collected into Tenax resin a...

  16. Liquid biofuel production from volatile fatty acids

    NARCIS (Netherlands)

    Steinbusch, K.J.J.

    2010-01-01

    The production of renewable fuels and chemicals reduces the dependency on fossil fuels and limits the increase of CO2 concentration in the atmosphere only if a sustainable feedstock and an energy efficient process are used. The thesis assesses the possibility to use municipal and industrial waste as

  17. Modelling Time-Varying Volatility in Financial Returns

    DEFF Research Database (Denmark)

    Amado, Cristina; Laakkonen, Helinä

    2014-01-01

    The “unusually uncertain” phase in the global financial markets has inspired many researchers to study the effects of ambiguity (or “Knightian uncertainty”) on the decisions made by investors and their implications for the capital markets. We contribute to this literature by using a modified...... version of the time-varying GARCH model of Amado and Teräsvirta (2013) to analyze whether the increasing uncertainty has caused excess volatility in the US and European government bond markets. In our model, volatility is multiplicatively decomposed into two time-varying conditional components: the first...... being captured by a stable GARCH(1,1) process and the second driven by the level of uncertainty in the financial market....

  18. 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

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

    Science.gov (United States)

    Cheong, Chin Wen

    2008-02-01

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

  20. Volatilization and reaction of fission products in flowing steam

    International Nuclear Information System (INIS)

    Johnson, I.; Steidl, D.V.; Johnson, C.E.

    1985-01-01

    The principal risk to the public from nuclear power plants derives from the highly radioactive atoms (fission products) generated as energy is produced in the nuclear fuel. The revolatilization of fission products from reactor system surfaces due to self-heating by radioactive decay has become a complicating factor in the source-term redefinition effort. It has had a major impact on calculations of fission product distributions in accident safety analyses. The focus of this research effort was to investigate the volatilization and transport of fission products and control rod materials in a flowing gaseous steam-hydrogen mixture. Fission product and control rod materials in various combinations were studied including CsI, CsOH, TeO 2 , SrO, Ag, In, Cd and Mn. The vaporization behavior of the deposits were characterized with respect to vaporization rates, chemical species and downstream transport behavior

  1. Secondary organic aerosol production from pinanediol, a semi-volatile surrogate for first-generation oxidation products of monoterpenes

    Science.gov (United States)

    Ye, Penglin; Zhao, Yunliang; Chuang, Wayne K.; Robinson, Allen L.; Donahue, Neil M.

    2018-05-01

    We have investigated the production of secondary organic aerosol (SOA) from pinanediol (PD), a precursor chosen as a semi-volatile surrogate for first-generation oxidation products of monoterpenes. Observations at the CLOUD facility at CERN have shown that oxidation of organic compounds such as PD can be an important contributor to new-particle formation. Here we focus on SOA mass yields and chemical composition from PD photo-oxidation in the CMU smog chamber. To determine the SOA mass yields from this semi-volatile precursor, we had to address partitioning of both the PD and its oxidation products to the chamber walls. After correcting for these losses, we found OA loading dependent SOA mass yields from PD oxidation that ranged between 0.1 and 0.9 for SOA concentrations between 0.02 and 20 µg m-3, these mass yields are 2-3 times larger than typical of much more volatile monoterpenes. The average carbon oxidation state measured with an aerosol mass spectrometer was around -0.7. We modeled the chamber data using a dynamical two-dimensional volatility basis set and found that a significant fraction of the SOA comprises low-volatility organic compounds that could drive new-particle formation and growth, which is consistent with the CLOUD observations.

  2. 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.

  3. Recovery of time-dependent volatility in option pricing model

    Science.gov (United States)

    Deng, Zui-Cha; Hon, Y. C.; Isakov, V.

    2016-11-01

    In this paper we investigate an inverse problem of determining the time-dependent volatility from observed market prices of options with different strikes. Due to the non linearity and sparsity of observations, an analytical solution to the problem is generally not available. Numerical approximation is also difficult to obtain using most of the existing numerical algorithms. Based on our recent theoretical results, we apply the linearisation technique to convert the problem into an inverse source problem from which recovery of the unknown volatility function can be achieved. Two kinds of strategies, namely, the integral equation method and the Landweber iterations, are adopted to obtain the stable numerical solution to the inverse problem. Both theoretical analysis and numerical examples confirm that the proposed approaches are effective. The work described in this paper was partially supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region (Project No. CityU 101112) and grants from the NNSF of China (Nos. 11261029, 11461039), and NSF grants DMS 10-08902 and 15-14886 and by Emylou Keith and Betty Dutcher Distinguished Professorship at the Wichita State University (USA).

  4. Multivariate Option Pricing with Time Varying Volatility and Correlations

    DEFF Research Database (Denmark)

    Rombouts, Jeroen V.K.; Stentoft, Lars Peter

    In recent years multivariate models for asset returns have received much attention, in particular this is the case for models with time varying volatility. In this paper we consider models of this class and examine their potential when it comes to option pricing. Specifically, we derive the risk...... neutral dynamics for a general class of multivariate heteroskedastic models, and we provide a feasible way to price options in this framework. Our framework can be used irrespective of the assumed underlying distribution and dynamics, and it nests several important special cases. We provide an application...... to options on the minimum of two indices. Our results show that not only is correlation important for these options but so is allowing this correlation to be dynamic. Moreover, we show that for the general model exposure to correlation risk carries an important premium, and when this is neglected option...

  5. Volatile fatty acids production in ruminants and the role of ...

    African Journals Online (AJOL)

    Yomi

    organic volatile fatty acids (VFAs) and microbial protein then become available to the host. .... BE, Drewes LR (2003). Molecular features, regulation and ... Dynamics of ruminal volatile fatty acids in black and white bulls before and after feeding ...

  6. 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.

  7. Formation of volatile decomposition products by self-radiolysis of tritiated thymidine

    International Nuclear Information System (INIS)

    Shiba, Kazuhiro; Mori, Hirofumi

    1997-01-01

    In order to estimate the internal exposure dose in an experiment using tritiated thymidine, the rate of volatile 3 H-decomposition of several tritiated thymidine samples was measured. The decomposition rate of (methyl- 3 H)thymidine in water was over 80% in less than one year after initial analysis. (methyl- 3 H)thymidine was decomposed into volatile and non-volatile 3 H-decomposition products. The ratio of volatile 3 H-decomposition products increased with increasing the rate of the decomposition of (methyl- 3 H) thymidine. The volatile 3 H-decomposition products consisted of two components, of which the main component was tritiated water. Internal exposure dose caused by the inhalation of such volatile 3 H-decomposition products of (methyl- 3 H) thymidine was assumed to be several μSv. (author)

  8. Lipid oxidation in baked products: impact of formula and process on the generation of volatile compounds.

    Science.gov (United States)

    Maire, Murielle; Rega, Barbara; Cuvelier, Marie-Elisabeth; Soto, Paola; Giampaoli, Pierre

    2013-12-15

    This paper investigates the effect of ingredients on the reactions occurring during the making of sponge cake and leading to the generation of volatile compounds related to flavour quality. To obtain systems sensitive to lipid oxidation (LO), a formulation design was applied varying the composition of fatty matter and eggs. Oxidation of polyunsaturated fatty acids (PUFA) and formation of related volatile compounds were followed at the different steps of cake-making. Optimised dynamic Solid Phase Micro Extraction was applied to selectively extract either volatile or semi-volatile compounds directly from the baking vapours. We show for the first time that in the case of alveolar baked products, lipid oxidation occurs very early during the step of dough preparation and to a minor extent during the baking process. The generation of lipid oxidation compounds depends on PUFA content and on the presence of endogenous antioxidants in the raw matter. Egg yolk seemed to play a double role on reactivity: protecting unsaturated lipids from oxidation and being necessary to generate a broad class of compounds of the Maillard reaction during baking and linked to the typical flavour of sponge cake. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Pretreatment of macroalgae for volatile fatty acid production.

    Science.gov (United States)

    Pham, Thi Nhan; Um, Youngsoon; Yoon, Hyon Hee

    2013-10-01

    In this study, a novel method was proposed for the biological pretreatment of macroalgae (Laminaria japonica, Pachymeniopsis elliptica, and Enteromorpha crinita) for production of volatile fatty acid (VFA) by anaerobic fermentation. The amount of VFA produced from 40 g/L of L. japonica increased from 8.3 g/L (control) to 15.6 g/L when it was biologically pretreated with Vibrio harveyi. The biological treatment of L. japonica with Vibrio spp. was most effective likely due to the alginate lyase activity of Vibrio spp. However, a considerable effect was also observed after biological pretreatment of P. elliptica and E. crinita, which are red and green algae, respectively. Alkaline pretreatment of 40 g/L of L. japonica with 0.5 N NaOH resulted in an increase of VFA production to 12.2 g/L. These results indicate that VFA production from macroalgae can be significantly enhanced using the proposed biological pretreatments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Estimation of volatility of selected oil production projects

    International Nuclear Information System (INIS)

    Costa Lima, Gabriel A.; Suslick, Saul B.

    2006-01-01

    In oil project valuation and investment decision-making, volatility is a key parameter, but it is difficult to estimate. From a traditional investment viewpoint, volatility reduces project value because it increases its discount rate via a higher risk premium. Contrarily, according to the real-option pricing theory, volatility may aggregate value to the project, since the downside potential is limited whereas the upside is theoretically unbounded. However, the estimation of project volatility is very complicated since there is not a historical series of project values. In such cases, many analysts assume that oil price volatility is equal to that of project. In order to overcome such problems, in this paper an alternative numerical method based on present value of future cash flows and Monte Carlo simulation is proposed to estimate the volatility of projects. This method is applied to estimate the volatility of 12 deep-water offshore oil projects considering that oil price will evolve according to one of two stochastic processes: Geometric Brownian Motion and Mean-Reverting Motion. Results indicate that the volatility of commodity usually undervalue that of project. For the set of offshore projects analyzed in this paper, project volatility is at least 79% higher than that of oil prices and increases dramatically in those cases of high capital expenditures and low price. (author)

  11. Occurence and dietary exposure of volatile and non-volatile N-Nitrosamines in processed meat products

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Duedahl-Olesen, Lene; Granby, Kit

    Nitrite and nitrate have for many decades been used for preservation of meat. However, nitrite can react with secondary amines in meat to form N-Nitrosamines (NAs), many of which have been shown to be genotoxic1 . The use of nitrite therefore ought to be limited as much as possible. To maintain...... a high level of consumer protection Denmark obtains National low limits of the nitrite use in meat products. An estimation of the dietary exposure to volatile NAs (VNA) and non-volatile NAs (NVNA) is necessary when performing a risk assessment of the use of nitrite and nitrate for meat preservation....

  12. Data on volatile compounds in fermented materials used for salmon fish sauce production.

    Science.gov (United States)

    Nakano, Mitsutoshi; Sagane, Yoshimasa; Koizumi, Ryosuke; Nakazawa, Yozo; Yamazaki, Masao; Watanabe, Toshihiro; Takano, Katsumi; Sato, Hiroaki

    2018-02-01

    This article describes the analysis of volatile compounds in fermented materials used for salmon fish sauce production via gas chromatography/mass spectrometry (GC/MS). Ten types of fish sauces were produced from raw salmon materials, including various proportions of flesh, viscera, inedible portion (heads, fins, and backbones), and soft roe, by mixing them with salt and allowing them to ferment for up to three months. The volatile compounds were captured by a solid-phase microextraction method and then applied to GC/MS for separation and identification of the compounds in the fish sauce products. The number of volatile compounds identified in the starting materials varied from 15 to 29 depending on the ingredients. The number of compounds in the final fish sauce products was reduced by 3.4-94.7% of that in the original material. The retention times and names of the identified compounds, as well as their relative peak areas, are provided in a Microsoft Excel Worksheet.

  13. Methods to assess secondary volatile lipid oxidation products in complex food matrices

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Yesiltas, Betül

    A range of different methods are available to determine secondary volatile lipid oxidation products. These methods include e.g. spectrophotometric determination of anisidine values and TBARS as well as GC based methods for determination of specific volatile oxidation products such as pentanal...... headspace methods on the same food matrices will be presented....

  14. Production of graphene by exfoliation of graphite in a volatile organic solvent

    International Nuclear Information System (INIS)

    Choi, Eun-Young; Choi, Won San; Lee, Young Boo; Noh, Yong-Young

    2011-01-01

    The production of unfunctionalized and nonoxidized graphene by exfoliation of graphite in a volatile solvent, 1-propanol, is reported. A stable homogeneous dispersion of graphene was obtained by mild sonication of graphite powder and subsequent centrifugation. The presence of a graphene monolayer was observed by atomic force microscopy and transmission electron microscopy. The solvent, 1-propanol, from the deposited dispersion was simply and quickly removed by air drying at room temperature, without the help of high temperature annealing or vacuum drying, which shortens production time and does not leave any residue of the solvent in the graphene sheets.

  15. Asymmetric News Effects on Volatility: Good vs. Bad News in Good vs. Bad Times

    OpenAIRE

    Laakkonen, Helinä; Lanne, Markku

    2008-01-01

    We study the impact of positive and negative macroeconomic US and European news announcements in different phases of the business cycle on the highfrequency volatility of the EUR/USD exchange rate. The results suggest that in general bad news increases volatility more than good news. The news effects also depend on the state of the economy: bad news increases volatility more in good times than in bad times, while there is no difference between the volatility effects of good news in bad and go...

  16. Optimal investment models with stochastic volatility: the time ...

    African Journals Online (AJOL)

    Therefore, a transform is primordial to express the value function in terms of a semilinear PDE with quadratic growth on the derivative term. Some proofs for the existence of smooth solution to this equation have been provided for this equation by Pham [11]. In that paper they illustrated some common stochastic volatility ...

  17. Verification of“Trend-Volatility Model”in Short-Term Forecast of Grain Production Potential

    Directory of Open Access Journals (Sweden)

    MI Chang-hong

    2016-02-01

    Full Text Available The "trend-volatility model" in short-term forecasting of grain production potential was verified and discussed systematically by using the grain production data from 1949 to 2014, in 16 typical counties and 6 typical districts, and 31 provinces, of China. The results showed as follows:(1 Size of forecast error reflected the precision of short-term production potential, the main reason of large prediction error was a great amount of high yield farmlands were occupied in developed areas and a great increase of vegetable and fruit planted that made grain yield decreased in a short time;(2 The micro-trend amendment method was a necessary part of "trend-volatility model", which could involve the short-term factors such as meteorological factors, science and technology input, social factors and other effects, while macro-trend prediction could not. Therefore, The micro-trend amendment method could improve the forecast precision.(3 In terms of actual situation in recent years in China, the more developed the areas was, the bigger the volatility of short-term production potential was; For the short-term production potential, the stage of increasing-decreasing-recovering also existed in developed areas;(4 In the terms of forecast precision of short-terms production potential, the scale of national was higher than the scale of province, the scale of province was higher than the scale of district, the scale of district was higher than the scale of county. And it was large differences in precision between different provinces, different districts and different counties respectively, which was concerned to the complementarity of domestic climate and the ability of the farmland resistance to natural disasters.

  18. Lipid oxidation and volatile production in irradiated raw pork batters prepared with commercial soybean oil containing vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Cheorun; Ahn, D.U.; Byun, M.W. E-mail: mwbyun@kaeri.re.kr

    2001-04-01

    An emulsion-type raw pork batter was prepared using 10% (meat weight) of backfat or commercial soybean oil enriched with vitamin E to determine the effect of irradiation on lipid oxidation and volatile production during storage. Batters (approximately 100 g) were vacuum- or aerobically packaged and irradiated at 0, 2.5 or 4.5 kGy. Irradiation increased lipid oxidation of aerobically packaged raw pork batters prepared with both backfat and soybean oil. Lipid oxidation of vacuum-packaged pork batters was not influenced by irradiation except for the batter prepared with backfat at day 0. Aerobically packaged batters prepared with soybean oil had lower (P<0.05) TBARS than that with backfat, but vacuum-packaged ones were not different. The sum of volatile compounds with short retention time (<1.80) increased by irradiation, and with storage time except for aerobic packaging at day 7. The amount of total volatile compounds had an increasing trend until day 3, but not at day 7. Irradiation increased the production of total volatile compounds in the batters prepared with soybean oil and vacuum packaged, but irradiation effect on volatile production was not consistent with other treatments.

  19. Lipid oxidation and volatile production in irradiated raw pork batters prepared with commercial soybean oil containing vitamin E

    International Nuclear Information System (INIS)

    Jo, Cheorun; Ahn, D.U.; Byun, M.W.

    2001-01-01

    An emulsion-type raw pork batter was prepared using 10% (meat weight) of backfat or commercial soybean oil enriched with vitamin E to determine the effect of irradiation on lipid oxidation and volatile production during storage. Batters (approximately 100 g) were vacuum- or aerobically packaged and irradiated at 0, 2.5 or 4.5 kGy. Irradiation increased lipid oxidation of aerobically packaged raw pork batters prepared with both backfat and soybean oil. Lipid oxidation of vacuum-packaged pork batters was not influenced by irradiation except for the batter prepared with backfat at day 0. Aerobically packaged batters prepared with soybean oil had lower (P<0.05) TBARS than that with backfat, but vacuum-packaged ones were not different. The sum of volatile compounds with short retention time (<1.80) increased by irradiation, and with storage time except for aerobic packaging at day 7. The amount of total volatile compounds had an increasing trend until day 3, but not at day 7. Irradiation increased the production of total volatile compounds in the batters prepared with soybean oil and vacuum packaged, but irradiation effect on volatile production was not consistent with other treatments

  20. Real time production optimization

    Energy Technology Data Exchange (ETDEWEB)

    Saputelli, Luigi; Otavio, Joao; Araujo, Turiassu; Escorcia, Alvaro [Halliburton, Houston, TX (United States). Landmark Division

    2004-07-01

    Production optimization encompasses various activities of measuring, analyzing, modeling, prioritizing and implementing actions to enhance productivity of a field. We present a state-of-the-art framework for optimizing production on a continuous basis as new sensor data is acquired in real time. Permanently acquired data is modeled and analyzed in order to create predictive models. A model based control strategy is used to regulate well and field instrumentation. The optimum field operating point, which changes with time, satisfies the maximum economic return. This work is a starting point for further development in automatic, intelligent reservoir technologies which get the most out of the abilities of permanent, instrumented wells and remotely activated downhole completions. The strategy, tested with history-matched data from a compartmentalised giant field, proved to reduce operating costs while increasing oil recovery by 27% in this field. (author)

  1. The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

    Directory of Open Access Journals (Sweden)

    Samantha Fairbairn

    2017-12-01

    Full Text Available Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

  2. Effects of exchange rate volatility on export volume and prices of forest products

    Science.gov (United States)

    Sijia Zhang; Joseph Buongiorno

    2010-01-01

    The relative value of currencies varies considerably over time. These fluctuations bring uncertainty to international traders. As a result, the volatility in exchange rate movements may influence the volume and the price of traded commodities. The volatility of exchange rates was measured by the variance of residuals in a GARCH(1,1) model of the exchange rate. We...

  3. The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

    OpenAIRE

    Samantha Fairbairn; Alexander McKinnon; Hannibal T. Musarurwa; António C. Ferreira; António C. Ferreira; Florian F. Bauer

    2017-01-01

    Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth p...

  4. Enhancing sludge biodegradability and volatile fatty acid production by tetrakis hydroxymethyl phosphonium sulfate pretreatment.

    Science.gov (United States)

    Wu, Qing-Lian; Guo, Wan-Qian; Bao, Xian; Yin, Ren-Li; Feng, Xiao-Chi; Zheng, He-Shan; Luo, Hai-Chao; Ren, Nan-Qi

    2017-09-01

    A new pretreatment method based on tetrakis hydroxymethyl phosphonium sulfate (THPS) biocide was tried to enhance sludge disintegration, and improved sludge biodegradability and subsequent volatile fatty acid (VFA) production. Sludge activity decreased to less than 10% after 2 days pretreatment using 20mg/g-TSS THPS, which also obviously destroyed EPS and cell membrane, and dissolved more biodegradable substances (48.8%) than raw sludge (19.7%). Moreover, 20mg/g-TSS THPS pretreatment shortened fermentation time to 4days and improved VFA production to 2778mg COD/L (4.35 times than that in control). Therein, the sum of n-butyric, n-valeric and iso-valeric acids unexpectedly accounted for 60.5% of total VFA (only 20.1% of that in control). The more high molecular weight VFAs (C4-C5) than low molecular VFAs (C2-C3) resulted from THPS pretreatment benefited to subsequent medium-chain volatile acids (C6-C12) generation to realize the separation and recovery of organic carbon more efficiently. Copyright © 2017. Published by Elsevier Ltd.

  5. [Analysis of Volatile Oils from Different Processed Products of Zingiber officinale Rhizome by GC-MS].

    Science.gov (United States)

    Zhao, Hong-bing; Wang, Zhi-hui; He, Fang; Meng, Han; Peng, Jian-hua; Shi, Ji-lian

    2015-04-01

    To analyze the volatile components in different processed products of Zingiber officinale rhizome, and to make clear the effect of different heating degree on them. The volatile components were extracted from four kinds of processed products by applying steam distillation, and then were analyzed by GC-MS. There were totally 43 components of volatile oil identified from four kinds of processed products of Zingiber officinale rhizome. Fresh product, dried product, and charcoal product of Zingiber officinale rhizome each had 27 components of volatile oil, while sand fried product contained 24 components. Fresh Zingiber officinale rhizome contained 22. 59% of zingiberene, 20. 87% of a-citral and 11. 01% of β-phellandrene, respectively. After processing in different heating degree, the volatile components changed greatly in both of their quantity and quality, For instance, dried Zingiber officinale rhizome contained 40. 48% of α-citral and 8-phellandrene content was slightly lower at 10. 38%. 32.73% of 3,7,11-trimethyl-l, 6, 10-dodecatriene,16. 38% of murolan-3, 9 (11)-diene-10-peroxy and 3. 36% of cubebene newly emerged in the sand fried Zingiber officinale rhizome, and eudesm-4 (14) and β-bisabolol, etc. However, β-phellandrene content was only 1. 95%. The zingiberene and β-sesquiphellandrene were the highest in charcoal product, besides, new components such as α-cedrene, decanal and γ-elemene appeared. Volatile components in different processed products of Zingiber officinale rhizome were different in both of their kinds and contents. This method is suitable for the analysis of volatile components in Zingiber officinale rhizome, and this study can provide the experimental evidence for quality evaluation and clinical application for ginger processed products.

  6. Online Estimation of Time-Varying Volatility Using a Continuous-Discrete LMS Algorithm

    Directory of Open Access Journals (Sweden)

    Jacques Oksman

    2008-09-01

    Full Text Available The following paper addresses a problem of inference in financial engineering, namely, online time-varying volatility estimation. The proposed method is based on an adaptive predictor for the stock price, built from an implicit integration formula. An estimate for the current volatility value which minimizes the mean square prediction error is calculated recursively using an LMS algorithm. The method is then validated on several synthetic examples as well as on real data. Throughout the illustration, the proposed method is compared with both UKF and offline volatility estimation.

  7. How Volatilities Nonlocal in Time Affect the Price Dynamics in Complex Financial Systems

    Science.gov (United States)

    Tan, Lei; Zheng, Bo; Chen, Jun-Jie; Jiang, Xiong-Fei

    2015-01-01

    What is the dominating mechanism of the price dynamics in financial systems is of great interest to scientists. The problem whether and how volatilities affect the price movement draws much attention. Although many efforts have been made, it remains challenging. Physicists usually apply the concepts and methods in statistical physics, such as temporal correlation functions, to study financial dynamics. However, the usual volatility-return correlation function, which is local in time, typically fluctuates around zero. Here we construct dynamic observables nonlocal in time to explore the volatility-return correlation, based on the empirical data of hundreds of individual stocks and 25 stock market indices in different countries. Strikingly, the correlation is discovered to be non-zero, with an amplitude of a few percent and a duration of over two weeks. This result provides compelling evidence that past volatilities nonlocal in time affect future returns. Further, we introduce an agent-based model with a novel mechanism, that is, the asymmetric trading preference in volatile and stable markets, to understand the microscopic origin of the volatility-return correlation nonlocal in time. PMID:25723154

  8. How volatilities nonlocal in time affect the price dynamics in complex financial systems.

    Directory of Open Access Journals (Sweden)

    Lei Tan

    Full Text Available What is the dominating mechanism of the price dynamics in financial systems is of great interest to scientists. The problem whether and how volatilities affect the price movement draws much attention. Although many efforts have been made, it remains challenging. Physicists usually apply the concepts and methods in statistical physics, such as temporal correlation functions, to study financial dynamics. However, the usual volatility-return correlation function, which is local in time, typically fluctuates around zero. Here we construct dynamic observables nonlocal in time to explore the volatility-return correlation, based on the empirical data of hundreds of individual stocks and 25 stock market indices in different countries. Strikingly, the correlation is discovered to be non-zero, with an amplitude of a few percent and a duration of over two weeks. This result provides compelling evidence that past volatilities nonlocal in time affect future returns. Further, we introduce an agent-based model with a novel mechanism, that is, the asymmetric trading preference in volatile and stable markets, to understand the microscopic origin of the volatility-return correlation nonlocal in time.

  9. Volatility Behaviors of Financial Time Series by Percolation System on Sierpinski Carpet Lattice

    Science.gov (United States)

    Pei, Anqi; Wang, Jun

    2015-01-01

    The financial time series is simulated and investigated by the percolation system on the Sierpinski carpet lattice, where percolation is usually employed to describe the behavior of connected clusters in a random graph, and the Sierpinski carpet lattice is a graph which corresponds the fractal — Sierpinski carpet. To study the fluctuation behavior of returns for the financial model and the Shanghai Composite Index, we establish a daily volatility measure — multifractal volatility (MFV) measure to obtain MFV series, which have long-range cross-correlations with squared daily return series. The autoregressive fractionally integrated moving average (ARFIMA) model is used to analyze the MFV series, which performs better when compared to other volatility series. By a comparative study of the multifractality and volatility analysis of the data, the simulation data of the proposed model exhibits very similar behaviors to those of the real stock index, which indicates somewhat rationality of the model to the market application.

  10. Fungal volatiles: Semiochemicals for stored-product beetles (Coleoptera: Cucujidae).

    Science.gov (United States)

    Pierce, A M; Pierce, H D; Borden, J H; Oehlschlager, A C

    1991-03-01

    Responses by five species of cucujid grain beetles (mixed-sex adults) to various volatiles were assessed by means of a two-choice, pitfall olfactometer. The test volatiles were short-chain alcohols and ketones known to be produced by fungi. Both racemic and chiral 1-octen-3-ols were strong attractants forCryptolestes ferrugineus (Stephens), as had been found previously forOryzaephilus surinamensis (L.),O. mercator (Fauvel), andAhasverus advena (Waltl). 3-Methylbutanol was another good attractant for these four cucujids, and it was the only test compound to whichCathartus quadricollis (Guér.) responded positively. 1-Octen-3-one, racemic 3-octanol, and 3-octanone showed various degrees of attractiveness for the former four species of cucujids.O. surinamensis was the only species of test beetle to show much positive response to 2-phenylethanol and ethanol. ForO. mercator andO. surinamensis, 3-methylbutanol enhanced positive response to their respective cucujolide aggregation pheromones.

  11. Thermodynamic analysis for syngas production from volatiles released in waste tire pyrolysis

    International Nuclear Information System (INIS)

    Martínez, Juan Daniel; Murillo, Ramón; García, Tomás; Arauzo, Inmaculada

    2014-01-01

    Highlights: • Pyrolysis experiments have been conducted in a continuous auger reactor. • Pyrolysis temperature influence on composition of both volatiles and char was studied. • A process for syngas production has been proposed from the volatiles. • Equivalence ratio down to 0.4 is a practical limit for syngas production. • The results provide essential data prior to perform any experimental campaign. - Abstract: This paper shows the maximum limit on syngas composition obtained from volatiles released in waste tire pyrolysis when they are submitted to an air–steam partial oxidation process. Thus, from mass and energy balances and a stoichiometric equilibrium model, syngas composition and reaction temperature as well as some process parameters were predicted by varying both the equivalence ratio (ER) and the steam to fuel ratio (SF). In addition, pyrolysis experiments were performed using a continuous auger reactor, and the influence of pyrolysis temperature on composition of both volatiles and char was studied. Consequently, the resulting syngas characteristics were correlated with the pyrolysis temperature. The stoichiometric equilibrium model showed that an ER down to 0.4 is a practical limit to perform the air–steam partial oxidation process. When the process is carried out only with air, volatiles obtained at high pyrolysis temperature lead to lower reaction temperature and higher LHV of syngas in comparison with those found at low pyrolysis temperature. The H 2 production is favored between 0.20 and 0.40 of ER and seems to be more influenced by the H/C ratio than by the water gas-shift reaction. On the other hand, the steam addition shows a more notable effect on the H 2 production for volatiles obtained at the highest pyrolysis temperature (600 °C) in agreement with the lower reaction temperature under these experimental conditions. This thermodynamic analysis provides essential data on the optimization of syngas production from volatiles

  12. PERVAPORATION MEMBRANE SYSTEMS FOR VOLATILE FERMENTATION PRODUCT RECOVERY AND DEHYDRATION

    Science.gov (United States)

    The economics of fermentative production of fuels and commodity chemicals can be a strong function of the efficiency with which the fermentation products are removed from the biological media. Due to growth inhibition by some fermentation products, including ethanol, concentrati...

  13. Volatile components of the enzyme-ripened sufu, a Chinese traditional fermented product of soy bean.

    Science.gov (United States)

    Moy, Yin-Soon; Lu, Ting-Jang; Chou, Cheng-Chun

    2012-02-01

    In the present study, sufu, a soft cheese-like oriental fermented food, was prepared by ripening the salted-tofu cubes in Aspergillus oryzae-fermented soybean-rice koji at 37°C for 16 days (16-day sufu). Sufu was further held at room temperature for another 30 days (46-day sufu). The volatile components of the non-fermented tofu cubes and the sufu products were identified and quantified by GC and GC-MS. A total of 70 volatile compounds including 20 aldehydes, 18 alcohols, 16 esters, 5 ketones, 5 acids and 6 other compounds were identified. Sufu products contained more volatile compounds than non-fermented tofu cubes qualitatively and quantitatively. After 16-days of ripening, fatty acid, aldehyde and ester were noted to be the dominant volatile fractions. In contrast, the 46-day sufu contained ester, and alcohol as the major volatile fractions. They comprise approximately 63.9% of the total volatile components. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. Bioelectrochemical recovery of waste-derived volatile fatty acids and production of hydrogen and alkali.

    Science.gov (United States)

    Zhang, Yifeng; Angelidaki, Irini

    2015-09-15

    Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode. At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net energy (5.20-6.86 kWh/kg-VFA recovered) was produced at all the applied voltages (0.8-1.4 V). The coexistence of other anionic species had no negative effect on VFA transportation. The VFA concentration was increased 2.96 times after three consecutive batches. Furthermore, the applicability of MBEDC was successfully verified with digestate. These results demonstrate for the first time the possibility of a new method for waste-derived VFA recovery and valuable products production that uses wastewater as fuel and bacteria as catalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Vaporization of low-volatile fission products under severe CANDU reactor accident conditions

    International Nuclear Information System (INIS)

    Lewis, B.J.; Corse, B.J.; Thompson, W.T.; Kaye, M.H.; Iglesias, F.C.; Elder, P.; Dickson, R.; Liu, Z.

    1997-01-01

    An analytical model has been developed to describe the release behaviour of low-volatile fission products from uranium dioxide fuel under severe reactor accident conditions. The effect of the oxygen potential on the chemical form and volatility of fission products is determined by Gibbs-energy minimization. The release kinetics are calculated according to the rate-controlling step of diffusional transport in the fuel matrix or fission product vaporization from the fuel surface. The effect of fuel volatilization (i.e., matrix stripping) on the release behaviour is also considered. The model has been compared to data from an out-of-pile annealing experiment performed in steam at the Chalk River Laboratories. (author)

  16. Time-varying correlation and common structures in volatility

    NARCIS (Netherlands)

    Liu, Yang

    2016-01-01

    This thesis studies time series properties of the covariance structure of multivariate asset returns. First, the time-varying feature of correlation is investigated at the intraday level with a new correlation model incorporating the intraday correlation dynamics. Second, the thesis develops a

  17. Lipid oxidation, color changes and volatiles production in irradiated pork sausage with different fat content and packaging during storage

    International Nuclear Information System (INIS)

    Jo, C.; Lee, J.I.; Ahn, D.U.

    1999-01-01

    Effects of irradiation on lipid oxidation, color and volatiles production in pork sausages with different fat content and packaging were determined. Sausages (with 4.7, 10.5 and 15.8% fat content) were sliced and vacuum-packaged either in oxygen-permeable or impermeable bags, irradiated (0 or 4.5 kGy) and stored at 4°C for 7 days. Lipid oxidation, color and volatiles productions were analyzed at 0, 3 and 7 days of storage. TBARS (2-thiobarbituric acid reactive substances) values of cooked pork sausages increased with the increase of fat content regardless of storage, irradiation or packaging types. Irradiated samples had higher TBARS than nonirradiated at 0 day but the difference disappeared during storage in both packaging types. Lightness of sausages (Hunter L-value) increased with the increase of fat content and storage time but was not affected by irradiation. In aerobic packaging, irradiation reduced Hunter a-values of pork sausages at 0 day but irradiation effect on a-value disappeared during storage. In vacuum packaging, however, irradiated samples had higher Hunter a-values than nonirradiated samples. Irradiation increased 1-heptene and total volatiles, but the amount of 1-heptene was not associated well with TBARS values of pork sausages. In both irradiated and nonirradiated pork sausages, aerobic packaging produced more volatiles than vacuum packaging during storage. It was concluded that irradiation and fat content had significant effects on lipid oxidation, color and volatiles production of cooked pork sausages during storage but that oxygen availability had a stronger effect than irradiation and fat content

  18. Incomplete Continuous-time Securities Markets with Stochastic Income Volatility

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Larsen, Kasper

    2014-01-01

    We derive closed-form solutions for the equilibrium interest rate and market price of risk processes in an incomplete continuous-time market with uncertainty generated by Brownian motions. The economy has a finite number of heterogeneous exponential utility investors, who receive partially...

  19. Incomplete Continuous-Time Securities Markets with Stochastic Income Volatility

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Larsen, Kasper

    In an incomplete continuous-time securities market governed by Brownian motions, we derive closed-form solutions for the equilibrium risk-free rate and equity premium processes. The economy has a finite number of heterogeneous exponential utility investors, who receive partially unspanned income ...

  20. Impact of production location, production system, and variety on the volatile organic compounds fingerprints and sensory characteristics of tomatoes

    NARCIS (Netherlands)

    Muilwijk, Mirthe; Heenan, Samuel; Koot, Alex; Ruth, Van Saskia M.

    2015-01-01

    Consumers have more and more interest in where and how their foods are produced. However, it is often challenging to discriminate products from different production locations and systems. The objective of this study was to examine fingerprinting of volatile organic compounds (VOCs) as an approach

  1. Real-time and online screening method for materials emitting volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Changhyuk [University of Minnesota, Department of Mechanical Engineering (United States); Sul, Yong Tae [Hoseo University (Korea, Republic of); Pui, David Y. H., E-mail: dyhpui@umn.edu [University of Minnesota, Department of Mechanical Engineering (United States)

    2016-09-15

    In the semiconductor industry, volatile organic compounds (VOCs) in the cleanroom air work as airborne molecular contamination, which reduce the production yield of semiconductor chips by forming nanoparticles and haze on silicon wafers and photomasks under ultraviolet irradiation during photolithography processes. Even though VOCs in outdoor air are removed by gas filters, VOCs can be emitted from many kinds of materials used in cleanrooms, such as organic solvents and construction materials (e.g., adhesives, flame retardants and sealants), threatening the production of semiconductors. Therefore, finding new replacements that emit lower VOCs is now essential in the semiconductor industry. In this study, we developed a real-time and online method to screen materials for developing the replacements by converting VOCs into nanoparticles under soft X-ray irradiation. This screening method was applied to measure VOCs emitted from different kinds of organic solvents and adhesives. Our results showed good repeatability and high sensitivity for VOCs, which come from aromatic compounds, some alcohols and all tested adhesives (Super glue and cleanroom-use adhesives). In addition, the overall trend of measured VOCs from cleanroom-use adhesives was well matched with those measured by a commercial thermal desorption–gas chromatography–mass spectrometry, which is a widely used off-line method for analyzing VOCs. Based on the results, this screening method can help accelerate the developing process for reducing VOCs in cleanrooms.

  2. Assessing Day-to-Day Volatility: Does the Trading Time Matter?

    Directory of Open Access Journals (Sweden)

    José Valentim Machado Vicente

    2014-06-01

    Full Text Available The aim of this study is to examine whether investors who trade daily but at different times have distinct perceptions about the risk of an asset. In order to capture the uncertainty faced by these investors, we define the volatility perceived by investors as the distribution of standard deviations of daily returns calculated from intraday prices collected randomly. We find that this distribution has a high degree of dispersion. This means that different investors may not share the same opinion regarding the variability of returns of the same asset. Moreover, the close-to-close volatility is often less than the median of the volatility distribution perceived by investors while the open-to-open volatility is greater than that statistic. From a practical point of view, our results indicate that volatilities estimated using traditional samples of daily returns (i.e., close-to-close and open-to-open returns may not do a good job when used as inputs in financial models since they may not properly capture the risk investors are exposed.

  3. Effects of Daylight Saving Time changes on stock market volatility: a reply.

    Science.gov (United States)

    Berument, Hakan; Dogan, Nukhet

    2011-12-01

    There is a rich array of evidence that suggests that changes in sleeping patterns affect an individual's decision-making processes. A nationwide sleeping-pattern change happens twice a year when the Daylight Saving Time (DST) change occurs. Kamstra, Kramer, and Levi argued in 2000 that a DST change lowers stock market returns. This study presents evidence that DST changes affect the relationship between stock market return and volatility. Empirical evidence suggests that the positive relationship between return and volatility becomes negative on the Mondays following DST changes.

  4. Duff reaction on phenols: Characterization of non steam volatile products

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; DeSouza, L.; Bhattacharya, J.

    New products having structures 1 and 2 have been characterized in the Duff reaction thymol arid carvacrol. These products have been identified as 2.6'-dithymylmethane 1 and 5.5' -dicarvacryl methane 2 respectively on the basis of spectral data...

  5. Real-Time Measurement of Volatile Chemicals Released by Bed Bugs during Mating Activities

    DEFF Research Database (Denmark)

    Kilpinen, Ole Østerlund; Liu, Dezhao; Adamsen, Anders Peter

    2012-01-01

    In recent years, bed bug (Hemiptera: Cimicidae) problems have increased dramatically in many parts of the world, leading to a renewed interest in their chemical ecology. Most studies of bed bug semiochemicals have been based on the collection of volatiles over a period of time followed by chemical...

  6. Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

    Science.gov (United States)

    Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

    2015-02-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Continuous-Time Models, Realized Volatilities, and Testable Distributional Implications for Daily Stock Returns

    DEFF Research Database (Denmark)

    Andersen, Torben G.; Bollerslev, Tim; Frederiksen, Per Houmann

    arrival process. On applying our sequential test procedure to the thirty individual stocks in the Dow Jones Industrial Average index, the data suggest that it is important to allow for both time-varying diffusive volatility, jumps, and leverage effects in order to satisfactorily describe the daily stock...

  8. Analysis of diacetylmorphine, caffeine, and degradation products after volatilization of pharmaceutical heroin for inhalation

    NARCIS (Netherlands)

    Klous, Marjolein G.; Lee, WeiChing; Hillebrand, Michel J. X.; van den Brink, Wim; van Ree, Jan M.; Beijnen, Jos H.

    2006-01-01

    Pharmaceutical smokable heroin was developed for a clinical trial on medical co-prescription of heroin and methadone. This product, consisting of 75% w/w diacetylmorphine base and 25% w/w caffeine anhydrate, was intended for use via "chasing the dragon", that is, inhalation after volatilization.

  9. THE KINETICS OF METHYL METHACRYLATE POLYMERIZATION INITIATED BY THE VOLATILE PRODUCTS OF A METHYL METHACRYLATE PLASMA

    Institute of Scientific and Technical Information of China (English)

    杨梅林; 马於光; 郑莹光; 沈家骢

    1990-01-01

    It is found that the volatile products of methyl methacrylate plasma can very actively initiate the polymerization of the monomer to produce ultrahigh molecular weight polymers. This polymerization of MMA occurs by a livlng free radical mechanism with instantaneous initiation and monomer transfer.

  10. Controlled release of volatiles under mild reaction conditions: from nature to everyday products.

    Science.gov (United States)

    Herrmann, Andreas

    2007-01-01

    Volatile organic compounds serve in nature as semiochemicals for communication between species, and are often used as flavors and fragrances in our everyday life. The quite limited longevity of olfactive perception has led to the development of pro-perfumes or pro-fragrances--ideally nonvolatile and odorless fragrance precursors which release the active volatiles by bond cleavage. Only a limited amount of reaction conditions, such as hydrolysis, temperature changes, as well as the action of light, oxygen, enzymes, or microorganisms, can be used to liberate the many different chemical functionalities. This Review describes the controlled chemical release of fragrances and discusses additional challenges such as precursor stability during product storage as well as some aspects concerning toxicity and biodegradability. As the same systems can be applied in different areas of research, the scope of this Review covers fragrance delivery as well as the controlled release of volatiles in general.

  11. Volatile fatty acids production in ruminants and the role of ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... Essential to these roles is their rapid transport across the plasma membrane, which is catalyzed ... The aim of this review is to critically discuss short-chain fatty acids production and the functional ... Two major functions of monocarboxylate transporter proteins, namely the facilitation of the ...

  12. A model for the release of low-volatility fission products in oxidizing conditions

    International Nuclear Information System (INIS)

    Cox, D.S.; Hunt, C.E.L.; Liu, Z.; Keller, N.A.; Barrand, R.D.; O'Connor, R.F.

    1991-07-01

    A thermodynamic and kinetic model has been developed for calculating low-volatility fission-product releases from UO 2 at high temperatures in oxidizing conditions. Volatilization of the UO 2 matrix is assumed to be the rate controlling process. Oxidation kinetics of the UO 2 are modelled by either interfacial rate control, gas phase oxidant transport control, or solid-state diffusion of oxygen. The vapour pressure of UO 3 in equilibrium with the oxidizing fuel is calculated from thermodynamic data, and volatilization rates are determined using a model for forced convective mass transport. Low-volatility fission-product releases are calculated from the volume of vapourized fuel. Model calculations are conservative compared to experimental data for Zr, La, Ce and Nb fission-product releases from irradiated UO 2 exposed to air at 1973-2350 K. The implications of this conservatism are discussed in terms of possible rate control by processes other than convective mass transport of UO 3 . Coefficients for effective surface area (based on experimental data) and for heterogeneous rate controlling reaction kinetics are introduced to facilitate agreement between calculations and the experimental data.

  13. Characterization of volatile production during storage of lettuce (Lactuca sativa) seed.

    Science.gov (United States)

    Mira, Sara; González-Benito, M Elena; Hill, Lisa M; Walters, Christina

    2010-09-01

    The duration that seeds stay vigorous during storage is difficult to predict but critical to seed industry and conservation communities. Production of volatile compounds from lettuce seeds during storage was investigated as a non-invasive and early detection method of seed ageing rates. Over 30 volatile compounds were detected from lettuce seeds during storage at 35 degrees C at water contents ranging from 0.03 to 0.09 g H(2)O g(-1) dw. Both qualitative and quantitative differences in volatile composition were noted as a function of water content, and these differences were apparent before signs of deterioration were visible. Seeds stored at high water content (L >or=0.06 g H(2)O g(-1) dw) emitted molecular species indicative of glycolysis (methanol+ethanol), and evidence of peroxidation was apparent subsequent to viability loss. Seeds containing less water (0.03-0.05 g H(2)O g(-1) dw) produced volatiles indicative of peroxidation and survived longer compared with seeds stored under more humid conditions. Production of glycolysis-related by-products correlated strongly with deterioration rate when measured as a function of water content. This correlation may provide a valuable non-invasive means to predict the duration of the early, asymptomatic stage of seed deterioration.

  14. Real-Time Science Operations to Support a Lunar Polar Volatiles Rover Mission

    Science.gov (United States)

    Heldmann, Jennifer L.; Colaprete, Anthony; Elphic, Richard C.; Mattes, Greg; Ennico, Kimberly; Fritzler, Erin; Marinova, Margarita M.; McMurray, Robert; Morse, Stephanie; Roush, Ted L.; hide

    2014-01-01

    Future human exploration of the Moon will likely rely on in situ resource utilization (ISRU) to enable long duration lunar missions. Prior to utilizing ISRU on the Moon, the natural resources (in this case lunar volatiles) must be identified and characterized, and ISRU demonstrated on the lunar surface. To enable future uses of ISRU, NASA and the CSA are developing a lunar rover payload that can (1) locate near subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. Such investigations are important both for ISRU purposes and for understanding the scientific nature of these intriguing lunar volatile deposits. Temperature models and orbital data suggest near surface volatile concentrations may exist at briefly lit lunar polar locations outside persistently shadowed regions. A lunar rover could be remotely operated at some of these locations for the approx. 2-14 days of expected sunlight at relatively low cost. Due to the limited operational time available, both science and rover operations decisions must be made in real time, requiring immediate situational awareness, data analysis, and decision support tools. Given these constraints, such a mission requires a new concept of operations. In this paper we outline the results and lessons learned from an analog field campaign in July 2012 which tested operations for a lunar polar rover concept. A rover was operated in the analog environment of Hawaii by an off-site Flight Control Center, a rover navigation center in Canada, a Science Backroom at NASA Ames Research Center in California, and support teams at NASA Johnson Space Center in Texas and NASA Kennedy Space Center in Florida. We find that this type of mission requires highly efficient, real time, remotely operated rover operations to enable low cost, scientifically relevant exploration of the distribution and nature of lunar polar volatiles. The field

  15. Symptoms of mothers and infants related to total volatile organic compounds in household products

    OpenAIRE

    Farrow, A; Taylor, H; Northstone, K; Golding, J

    2003-01-01

    The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that ...

  16. Wine phenolic compounds influence the production of volatile phenols by wine-related lactic acid bacteria.

    Science.gov (United States)

    Silva, I; Campos, F M; Hogg, T; Couto, J A

    2011-08-01

    To evaluate the effect of wine phenolic compounds on the production of volatile phenols (4-vinylphenol [4VP] and 4-ethylphenol [4EP]) from the metabolism of p-coumaric acid by lactic acid bacteria (LAB). Lactobacillus plantarum, Lactobacillus collinoides and Pediococcus pentosaceus were grown in MRS medium supplemented with p-coumaric acid, in the presence of different phenolic compounds: nonflavonoids (hydroxycinnamic and benzoic acids) and flavonoids (flavonols and flavanols). The inducibility of the enzymes involved in the p-coumaric acid metabolism was studied in resting cells. The hydroxycinnamic acids tested stimulated the capacity of LAB to synthesize volatile phenols. Growth in the presence of hydroxycinnamic acids, especially caffeic acid, induced the production of 4VP by resting cells. The hydroxybenzoic acids did not significantly affect the behaviour of the studied strains. Some of the flavonoids showed an effect on the production of volatile phenols, although strongly dependent on the bacterial species. Relatively high concentrations (1 g l(-1) ) of tannins inhibited the synthesis of 4VP by Lact. plantarum. Hydroxycinnamic acids were the main compounds stimulating the production of volatile phenols by LAB. The results suggest that caffeic and ferulic acids induce the synthesis of the cinnamate decarboxylase involved in the metabolism of p-coumaric acid. On the other hand, tannins exert an inhibitory effect. This study highlights the capacity of LAB to produce volatile phenols and that this activity is markedly influenced by the phenolic composition of the medium. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  17. 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

  18. Assessment of ecotoxicity and total volatile organic compound (TVOC) emissions from food and children's toy products.

    Science.gov (United States)

    Szczepańska, Natalia; Marć, Mariusz; Kudłak, Błażej; Simeonov, Vasil; Tsakovski, Stefan; Namieśnik, Jacek

    2018-09-30

    The development of new methods for identifying a broad spectrum of analytes, as well as highly selective tools to provide the most accurate information regarding the processes and relationships in the world, has been an area of interest for researchers for many years. The information obtained with these tools provides valuable data to complement existing knowledge but, above all, to identify and determine previously unknown hazards. Recently, attention has been paid to the migration of xenobiotics from the surfaces of various everyday objects and the resulting impacts on human health. Since children are among those most vulnerable to health consequences, one of the main subjects of interest is the migration of low-molecular-weight compounds from toys and products intended for children. This migration has become a stimulus for research aimed at determining the degree of release of compounds from popular commercially available chocolate/toy sets. One of main objectives of this research was to determine the impact of time on the ecotoxicity (with Vibrio fischeri bioluminescent bacteria) of extracts of products intended for children and to assess the correlation with total volatile organic compound emissions using basic chemometric methods. The studies on endocrine potential (with XenoScreen YES/YAS) of the extracts and showed that compounds released from the studied objects (including packaging foils, plastic capsules storing toys, most of toys studied and all chocolate samples) exhibit mostly androgenic antagonistic behavior while using artificial saliva as extraction medium increased the impact observed. The impact of time in most cases was positive one and increased with prolonging extraction time. The small-scale stationary environmental test chambers - μ-CTE™ 250 system was employed to perform the studies aimed at determining the profile of total volatile organic compounds (TVOCs) emissions. Due to this it was possible to state that objects from which the

  19. Selective Trapping of Volatile Fission Products with an Off-Gas Treatment System

    Energy Technology Data Exchange (ETDEWEB)

    B.R. Westphal; J.J. Park; J.M. Shin; G.I. Park; K.J. Bateman; D.L. Wahlquist

    2008-07-01

    A head-end processing step, termed DEOX for its emphasis on decladding via oxidation, is being developed for the treatment of spent oxide fuel by pyroprocessing techniques. The head-end step employs high temperatures to oxidize UO2 to U3O8 resulting in the separation of fuel from cladding and the removal of volatile fission products. Development of the head-end step is being performed in collaboration with the Korean Atomic Energy Research Institute (KAERI) through an International Nuclear Energy Research Initiative. Following the initial experimentation for the removal of volatile fission products, an off-gas treatment system was designed in conjunction with KAERI to collect specific fission gases. The primary volatile species targeted for trapping were iodine, technetium, and cesium. Each species is intended to be collected in distinct zones of the off-gas system and within those zones, on individual filters. Separation of the volatile off-gases is achieved thermally as well as chemically given the composition of the filter media. A description of the filter media and a basis for its selection will be given along with the collection mechanisms and design considerations. In addition, results from testing with the off-gas treatment system will be presented.

  20. Analysis of volatile organic compounds in compost samples: A potential tool to determine appropriate composting time.

    Science.gov (United States)

    Zhu, Fengxiang; Pan, Zaifa; Hong, Chunlai; Wang, Weiping; Chen, Xiaoyang; Xue, Zhiyong; Yao, Yanlai

    2016-12-01

    Changes in volatile organic compound contents in compost samples during pig manure composting were studied using a headspace, solid-phase micro-extraction method (HS-SPME) followed by gas chromatography with mass spectrometric detection (GC/MS). Parameters affecting the SPME procedure were optimized as follows: the coating was carbon molecular sieve/polydimethylsiloxane (CAR/PDMS) fiber, the temperature was 60°C and the time was 30min. Under these conditions, 87 compounds were identified from 17 composting samples. Most of the volatile components could only be detected before day 22. However, benzenes, alkanes and alkenes increased and eventually stabilized after day 22. Phenol and acid substances, which are important factors for compost quality, were almost undetectable on day 39 in natural compost (NC) samples and on day 13 in maggot-treated compost (MC) samples. Our results indicate that the approach can be effectively used to determine the composting times by analysis of volatile substances in compost samples. An appropriate composting time not only ensures the quality of compost and reduces the loss of composting material but also reduces the generation of hazardous substances. The appropriate composting times for MC and NC were approximately 22days and 40days, respectively, during the summer in Zhejiang. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Volatility Degree Forecasting of Stock Market by Stochastic Time Strength Neural Network

    Directory of Open Access Journals (Sweden)

    Haiyan Mo

    2013-01-01

    Full Text Available In view of the applications of artificial neural networks in economic and financial forecasting, a stochastic time strength function is introduced in the backpropagation neural network model to predict the fluctuations of stock price changes. In this model, stochastic time strength function gives a weight for each historical datum and makes the model have the effect of random movement, and then we investigate and forecast the behavior of volatility degrees of returns for the Chinese stock market indexes and some global market indexes. The empirical research is performed in testing the prediction effect of SSE, SZSE, HSI, DJIA, IXIC, and S&P 500 with different selected volatility degrees in the established model.

  2. Evaluation of peroxidative stress of cancer cells in vitro by real-time quantification of volatile aldehydes in culture headspace.

    Science.gov (United States)

    Shestivska, Violetta; Rutter, Abigail V; Sulé-Suso, Josep; Smith, David; Španěl, Patrik

    2017-08-30

    Peroxidation of lipids in cellular membranes results in the release of volatile organic compounds (VOCs), including saturated aldehydes. The real-time quantification of trace VOCs produced by cancer cells during peroxidative stress presents a new challenge to non-invasive clinical diagnostics, which as described here, we have met with some success. A combination of selected ion flow tube mass spectrometry (SIFT-MS), a technique that allows rapid, reliable quantification of VOCs in humid air and liquid headspace, and electrochemistry to generate reactive oxygen species (ROS) in vitro has been used. Thus, VOCs present in the headspace of CALU-1 cancer cell line cultures exposed to ROS have been monitored and quantified in real time using SIFT-MS. The CALU-1 lung cancer cells were cultured in 3D collagen to mimic in vivo tissue. Real-time SIFT-MS analyses focused on the volatile aldehydes: propanal, butanal, pentanal, hexanal, heptanal and malondialdehyde (propanedial), that are expected to be products of cellular membrane peroxidation. All six aldehydes were identified in the culture headspace, each reaching peak concentrations during the time of exposure to ROS and eventually reducing as the reactants were depleted in the culture. Pentanal and hexanal were the most abundant, reaching concentrations of a few hundred parts-per-billion by volume, ppbv, in the culture headspace. The results of these experiments demonstrate that peroxidation of cancer cells in vitro can be monitored and evaluated by direct real-time analysis of the volatile aldehydes produced. The combination of adopted methodology potentially has value for the study of other types of VOCs that may be produced by cellular damage. Copyright © 2017 John Wiley & Sons, Ltd.

  3. The transitory and permanent volatility of oil prices: What implications are there for the US industrial production?

    International Nuclear Information System (INIS)

    Ali Ahmed, Huson Joher; Bashar, Omar H.M.N.; Wadud, I.K.M. Mokhtarul

    2012-01-01

    Highlights: ► This study examines the impact of oil price uncertainty on the US industrial production (IPI). ► The transitory component of the oil price volatility has an adverse impact on the US IPI. ► The transitory oil price volatility induces higher volatility in CPI, commodity prices and IPI. -- Abstract: This study examines the impact of oil price uncertainty on the US industrial production by decomposing oil price volatility into permanent and transitory components. The decompositions provide important evidence on sources and asymmetric effects of oil price volatility. To estimate the component structure of volatility and to analyse the dynamic impacts of the volatility components, the study uses a threshold based CGARCH and VAR modelling over a period from 1980 to 2010 for the US economy. The CGARCH model estimates show significant asymmetric effect of oil price shock on the transitory oil price volatility. Dynamic impulse response functions obtained from the estimated VAR models reveal that there is a significant and prolonged dampening impact of increased transitory oil price volatility on industrial production. The results also suggest that shocks to transitory component induce increased volatility in the general price level and non-fuel commodity prices in the US. Variance decomposition analysis reconfirms that the transitory volatility is the second most important factor to explain the variance of industrial production. These results provide additional insights on the sources of oil price uncertainty and point to the need to direct US energy policies towards stabilising short-term uncertainties in oil prices.

  4. Lipid and cholesterol oxidation, color changes, and volatile compounds production in irradiated raw pork batters with different fat content

    International Nuclear Information System (INIS)

    Jo, Cheo Run; Byun, Myung Woo

    2000-01-01

    An emulsion-type product was prepared to determine the effect of irradiation on lipid and cholesterol oxidation, color change, and volatile production in raw pork with different fat content. Lipid oxidation increased with an increase in fat content or irradiation dose. Irradiated batters had higher cholesterol oxides than did non-irradiated batters, and the major cholesterol oxides formed in irradiated pork batters were 7α- and 7β- hydroxycholesterol. Hunter color a- and b-values of raw pork batters were decreased by irradiation regardless of fat content. Irradiation significantly increased the amount of volatile compounds. Although lipid oxidation of high fat products (10 and 15% fat) was higher than that of low fat products (4%), high fat products did not always produce greater amount of volatile compounds in raw pork batters. In summary, irradiation increased lipid and cholesterol oxidation, and volatile compounds production, and had detrimental effects on the color of raw pork batter under aerobic conditions

  5. Biotic and abiotic factors affect green ash volatile production and emerald ash borer adult feeding preference.

    Science.gov (United States)

    Chen, Yigen; Poland, Therese M

    2009-12-01

    The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an exotic woodborer first detected in 2002 in Michigan and Ontario and is threatening the ash resource in North America. We examined the effects of light exposure and girdling on green ash (Fraxinus pennsylvanica Marsh) volatile production, and effects of light exposure, girdling, and leaf age on emerald ash borer adult feeding preferences and phototaxis. Green ash seedlings grown under higher light exposure had lower amounts of three individual volatile compounds, (Z)-3-hexenol, (E)-beta-ocimene, and (Z,E)-alpha-farnesene, as well as the total amount of six detected volatile compounds. Girdling did not affect the levels of these volatiles. Emerald ash borer females preferred mature leaves, leaves from girdled trees, and leaves grown in the sun over young leaves, leaves from nongirdled trees, and leaves grown in the shade, respectively. These emerald ash borer preferences were most likely because of physical, nutritional, or biochemical changes in leaves in response to the different treatments. Emerald ash borer females and males showed positive phototaxis in laboratory arenas, a response consistent with emerald ash borer preference for host trees growing in sunlight.

  6. Volatiles production from the coking of coal; Sekitan no netsubunkai ni okeru kihatsubun seisei

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Y.; Saito, H.; Inaba, A. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    In order to simplify the coke manufacturing process, a coke production mechanism in coal pyrolysis was discussed. Australian bituminous coal which can produce good coke was used for the discussion. At a temperature raising rate of 50{degree}C per minute, coal weight loss increases monotonously. However, in the case of 3{degree}C, the weight loss reaches a peak at a maximum ultimate temperature of about 550{degree}C. The reaction mechanism varies with the temperature raising rates, and in the case of 50{degree}C per minute, volatiles other than CO2 and propane increased. Weight loss of coal at 3{degree}C per minute was caused mainly by methane production at 550{degree}C or lower. When the temperature is raised to 600{degree}C, tar and CO2 increased, and so did the weight loss. Anisotropy was discerned in almost of all coke particles at 450{degree}C, and the anisotropy became remarkable with increase in the maximum ultimate temperature. Coke and volatiles were produced continuously at a temperature raising rate of 50{degree}C per minute, and at 3{degree}C per minute, the production of the coke and volatiles progressed stepwise as the temperature has risen. 7 refs., 6 figs.

  7. 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.

  8. Investigation the Impact of Exchange Rate Volatility on the Export of Agricultural Products

    Directory of Open Access Journals (Sweden)

    M. Jamalipour

    2016-10-01

    coefficients. Results and Discussion: Main results showed that real exchange rate volatility and export value of selected commodities are Co-integrated. The coefficient estimation of FMOLS and DOLS methods are equal and statically significant; so, these methods aren’t statically different and they showed that real exchange rate volatility has a negative impact on exported value for whole panel. However, the specific coefficient for each commodity showed contradictory behavior in short run and long run; for example real exchange rate fluctuation has a negative and significant impact on all the commodities; but, in short run this variable has a positive and significant impact on exported value. Moreover, based on estimated results it seems that fluctuation in exchange market has a greater impact on more valuable commodities like date. Conclusion: Considering the importance of agricultural product trade and in order to overcome mono-product economy, this study investigated long term and short term relation between export of grape, orange, date and exchange rate volatilities. To this aim, first the index of exchange volatility using generated autoregressive conditional heteroscedasticity (GARCH was calculated. In order to investigate the relation between exchange rate volatilities and export value of agricultural product, unit root test and cointegration test related to panel data were used during years 1971-2013. The results of model estimation showed that exchange rate volatilities in short term and long term have respectively positive and negative effects on the export value of orange, grape and date. In long term, the negative effects of Exchange rate volatilities on high-export-value products are more than its effects on low-export-value products. Based on the estimation results we can conclude that, in short run, exporters are willing to increase their interchange and gain profits of the volatility in exchange market; however, in long run exchange rate fluctuation has

  9. Identification and Quantification of Volatile Compounds Found in Vinasses from Two Different Processes of Tequila Production

    Directory of Open Access Journals (Sweden)

    Elizabeth Rodríguez-Félix

    2018-02-01

    Full Text Available Vinasses are the main byproducts of ethanol distillation and distilled beverages worldwide and are generated in substantial volumes. Tequila vinasses (TVs could be used as a feedstock for biohydrogen production through a dark fermentative (DF process due to their high content of organic matter. However, TV components have not been previously assayed in order to evaluate if they may dark ferment. This work aimed to identify and quantify volatile compounds (VC in TV and determine if the VC profile depends upon the type of production process (whether the stems were initially cooked or not. TVs were sampled from 3 agave stems with a not-cooking (NC process, and 3 agave stems with a cooking (C process, and volatile compounds were determined by gas chromatography coupled with mass spectrometry (GC–MS. A total of 111 volatile compounds were identified, the TV from the cooking process (C showed the higher presence of furanic compounds (furfural and 5-(hydroxymethyl furfural and organic acids (acetic acid and butyric acid, which have been reported as potential inhibitors for DF. To our knowledge, this is the first description of the VC composition from TVs. This study could serve as a base for further investigations related to vinasses from diverse sources.

  10. Volatile chemical products emerging as largest petrochemical source of urban organic emissions

    Science.gov (United States)

    McDonald, Brian C.; de Gouw, Joost A.; Gilman, Jessica B.; Jathar, Shantanu H.; Akherati, Ali; Cappa, Christopher D.; Jimenez, Jose L.; Lee-Taylor, Julia; Hayes, Patrick L.; McKeen, Stuart A.; Cui, Yu Yan; Kim, Si-Wan; Gentner, Drew R.; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Harley, Robert A.; Frost, Gregory J.; Roberts, James M.; Ryerson, Thomas B.; Trainer, Michael

    2018-02-01

    A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)—including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products—now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.

  11. Production of volatile and sulfur compounds by ten Saccharomyces cerevisiae strains inoculated in Trebbiano must

    Directory of Open Access Journals (Sweden)

    Francesca ePatrignani

    2016-03-01

    Full Text Available In wines, the presence of sulphur compounds is the resulting of several contributions among which yeast metabolism. The characterization of the starter Saccharomyces cerevisiae needs to be performed also taking into account this ability even if evaluated together with the overall metabolic profile. In this perspective, principal aim of this experimental research was the evaluation of the volatile profiles, throughout GC/MS technique coupled with solid phase micro extraction, of wines obtained throughout the fermentation of 10 strains of Saccharomyces cerevisiae. In addition, the production of sulphur compounds was further evaluated by using a gas-chromatograph coupled with a Flame Photometric Detector. Specifically, the ten strains were inoculated in Trebbiano musts and the fermentations were monitored for 19 days. In the produced wines, volatile and sulphur compounds as well as amino acid concentrations were investigated. Also the physico-chemical characteristics of the wines and their electronic nose profiles were evaluated.

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

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Duedahl-Olesen, Lene; Christensen, Tue

    2015-01-01

    the carcinogenicity for the majority of the non-volatile NA (NVNA) remains to be elucidated. Danish adults (15–75 years) and children (4–6 years) consume 20 g and 16 g of processed meat per day (95th percentile), respectively. The consumption is primarily accounted for by sausages, salami, pork flank (spiced...

  13. Use of a free-jet expansion, molecular beam mass spectrometer to understand processes involving volatile corrosion products

    International Nuclear Information System (INIS)

    Jacobson, N.S.

    1997-01-01

    Many high-temperature corrosion processes generate volatile products in addition to condensed phase products. Examples of these volatile products are chlorides, oxychlorides, and certain oxides and hydroxyl species. One of the best techniques to identify high temperature vapor molecules is mass spectrometry. Most mass spectrometers operate in high vacuum and are generally used to examine processes ocurring at greatly reduced pressures. However, a free-jet expansion, molecular beam mass spectrometer system allows direct sampling of volatile corrosion products. This instrument is described. Several examples from our studies on chlorination/oxidation of metals and ceramics are discussed. In addition, reactions of Cr 2 O 3 , SiO 2 , and Al 2 O 3 with water vapor, which produce volatile hydroxyl species are discussed. (orig.)

  14. Influence of physiological state of inoculum on volatile acidity production by Saccharomyces cerevisiae during high sugar fermentation

    Directory of Open Access Journals (Sweden)

    Marina Bely

    2005-12-01

    Full Text Available An approach consisting of controlling yeast inoculum to minimize volatile acidity production by Saccharomyces cerevisiae during the alcoholic fermentation of botrytized must was investigated. Direct inoculation of rehydrated active dry yeasts produced the most volatile acidity, while a yeast preparation pre-cultured for 24 hours reduced the final production by up to 23 %. Using yeasts collected from a fermenting wine as a starter must also reduced volatile acidity production. The conditions for preparing the inoculum affected the fermentation capacity of the first generation yeasts: fermentation duration, sugar to ethanol ratio, and wine composition. A pre-culture medium with a low sugar concentration (< 220 g/L is essential to limit volatile acidity production in high sugar fermentations.

  15. Agricultural management, season and trace elements effects on volatile oil production from Melissa officinalis L. (Lemon balm)

    International Nuclear Information System (INIS)

    Sussa, Fabio Vitorio; Duarte, Celina Lopes; Silva, Paulo Sergio Cardoso da; Furlan, Marcos Roberto

    2016-01-01

    The objective of this study was to provide information about organic and mineral fertilization, season and trace elements effects on volatile oil production by the species Melissa officinalis. Elemental concentration was determined by instrumental neutron activation analysis and atomic absorption spectrometry. The volatile oil was extracted by hydrodistillation and analyzed by gas chromatography coupled to a mass spectrometer. The elemental content and the main compounds vary according to agricultural management and season. The results indicate that the production of volatile oil main compounds from M. officinalis is correlated with the concentrations of Na, Co, Rb, Cd, Cs, La, Sm and Hf. (author)

  16. Production of volatiles in fresh-cut apple: effect of applying alginate coatings containing linoleic acid or isoleucine.

    Science.gov (United States)

    Maya-Meraz, Irma O; Espino-Díaz, Miguel; Molina-Corral, Francisco J; González-Aguilar, Gustavo A; Jacobo-Cuellar, Juan L; Sepulveda, David R; Olivas, Guadalupe I

    2014-11-01

    One of the main quality parameters in apples is aroma, its main precursors are fatty acids (FA) and amino acids (AA). In this study, alginate edible coatings were used as carriers of linoleic acid or isoleucine to serve as precursors for the production of aroma in cut apples. Apple wedges were immersed in a CaCl2 solution and coated with one of the following formulations: alginate solution (Alg-Ca), Alg-Ca-low-level linoleic acid (0.61 g/Lt), (LFA), Alg-Ca-high-level linoleic acid (2.44 g/L; HFA), Alg-Ca-low-level isoleucine (0.61 g/L; LAA), and Alg-Ca-high-level isoleucine (2.44 g/L; HAA). Apple wedges were stored at 3 °C and 85% relative humidity for 21 d and key volatiles were studied during storage. Addition of precursors, mainly isoleucine, showed to increase the production of some key volatiles on coated fresh-cut apples during storage. The concentration of 2-methyl-1-butanol was 4 times higher from day 12 to day 21 in HAA, while 2-methyl butyl acetate increased from day 12 to day 21 in HAA. After 21 d, HAA-apples presented a 40-fold value of 2-methyl-butyl acetate, compared to Alg-Ca cut apples. Values of hexanal increased during cut apple storage when the coating carried linoleic acid, mainly on HFA, from 3 to 12 d. The ability of apples to metabolize AA and FA depends on the concentration of precursors, but also depends on key enzymes, previous apple storage, among others. Further studies should be done to better clarify the behavior of fresh-cut apples as living tissue to metabolize precursors contained in edible coatings for the production of volatiles. © 2014 Institute of Food Technologists®

  17. Growth and production of volatiles by Staphylococcus carnosus in dry sausages:

    DEFF Research Database (Denmark)

    Tjener, Karsten; Stahnke, Louise Heller; Andersen, L.

    2004-01-01

    Three sausage batches inoculated with normal inoculation level of Pediococcus pentosaceus (5 x 10(6) CFU/g) and with low, intermediate, and high inoculation levels of Staphylococcus carnosus (10(5), 5 x 10(6), 5 x 10(7) CFU/g, respectively) were produced. Cell counts and formation of volatiles were...... followed throughout a ripening period of three weeks. The staphylococci exhibited the fastest growth in sausages with a low inoculation level, whereas growth was only moderate in sausages with a high initial level. Analysis of volatiles showed that methyl-branched aldehydes and acids, phenylacetaldehyde, 2......-methyl-l-butanol, dimethyldisulphide and dimethyltrisulphide were produced in higher amounts in sausages with a high inoculation level of S. carnosus, whercas a low inoculation level correlated with high amounts of diacetyl, ethanol and ethyl esters. The levels of most compounds increased over time...

  18. Impact of Storage Time on the Needed Capture Efficiency for Volatile Radionuclides - 13369

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.; Ilas, G. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37849 (United States); Soelberg, N.R. [Idaho National Laboratory (United States); Strachan, D.M. [Pacific Northwest National Laboratory (United States)

    2013-07-01

    During the processing of used nuclear fuel (UNF), volatile radionuclides will be discharged from the facility stack if no recovery processes are in place to limit their release. The volatile radionuclides of concern are {sup 3}H, {sup 14}C, {sup 85}Kr, and {sup 129}I. There are three key regulations that address the release of these radionuclides to the environment- 40 CFR 61, 40 CFR 190, and 10 CFR 20. These regulations apply to the total radionuclide release and establish dose limits for the maximum exposed individual (MEI) in the public both in terms of whole body dose and dose to specific organs such as the thyroid. Each radionuclide released to the environment contributes to the total dose to some degree. In this paper we attempt to evaluate the efficiency requirements for the capture processes to limit the doses to the MEI to regulatory levels. Since the total amount of each volatile radionuclide present in the UNF changes with the age of the fuel, the respective capture requirements also change with time. Specifically, we are interested in the impact of the decreasing contribution of {sup 3}H and {sup 85}Kr, which have relatively short half-lives, 12.32 y and 10.76 y, respectively, with the increasing age of the fuel (i.e., time between when the UNF is removed from the reactor and the time it is processed) on the capture requirements. In this paper we examine the capture requirements for these four radionuclides for three fuel types (pressurized water reactor [PWR] with uranium oxide fuel [UOX], PWR with mixed oxide fuel [MOX], and an advanced high temperature gas-cooled reactor [AHTGR]), several burnup values, and time out of reactor extending to 200 y. We calculate doses to the MEI with the EPA code CAP-88 and look at two dose contribution cases. In the first case, we assume that the total allowable dose is attributed to only the four volatile radionuclides. This establishes the lowest capture efficiency value possible. Since this is unrealistic, because

  19. Volatile Discrimination of Irradiated and Fumigated White Ginseng Powders at Different Storage Times and Temperatures Using the Electronic Nose

    International Nuclear Information System (INIS)

    Kwon, J.H.; Shin, J.A.; Lee, K.T.

    2006-01-01

    The pattern of volatile emissions from white ginseng powders (WGP) that were treated with selected preservatives was investigated during 5-months of storage (at-10 and 25℃) by an electronic nose system equipped with 12 metal-oxide sensors. WGP were treated with gamma radiation at 5 kGy, commercial methyl bromide (MeBr), and phosphine fumigations. Electronic nose differentiated the volatile patterns of the WGP with each different preservative treatment. In addition, each volatile pattern was affected by both storage time (1, 2 and 5 months) and temperature (-10 and 25℃)

  20. Production of hydrogen and volatile fatty acid by Enterobacter sp. T4384 using organic waste materials.

    Science.gov (United States)

    Kim, Byung-Chun; Deshpande, Tushar R; Chun, Jongsik; Yi, Sung Chul; Kim, Hyunook; Um, Youngsoon; Sang, Byoung-In

    2013-02-01

    In a study of hydrogen-producing bacteria, strain T4384 was isolated from rice field samples in the Republic of Korea. The isolate was identified as Enterobacter sp. T4384 by phylogenetic analysis of 16S rRNA and rpoB gene sequences. Enterobacter sp. T4384 grew at a temperature range of 10-45 degrees C and at an initial pH range of 4.5-9.5. Strain T4384 produced hydrogen at 0-6% NaCl by using glucose, fructose, and mannose. In serum bottle cultures using a complete medium, Enterobacter sp. T4384 produced 1,098 ml/l H2, 4.0 g/l ethanol, and 1.0 g/l acetic acid. In a pH-regulated jar fermenter culture with the biogas removed, 2,202 ml/l H2, 6.2 g/l ethanol, and 1.0 g/l acetic acid were produced, and the lag-phase time was 4.8 h. Strain T4384 metabolized the hydrolysate of organic waste for the production of hydrogen and volatile fatty acid. The strain T4384 produced 947 ml/l H2, 3.2 g/l ethanol, and 0.2 g/l acetic acid from 6% (w/v) food waste hydrolysate; 738 ml/l H2, 4.2 g/l ethanol, and 0.8 g/l acetic acid from Miscanthus sinensis hydrolysate; and 805 ml/l H2, 5.0 g/l ethanol, and 0.7 g/l acetic acid from Sorghum bicolor hydrolysate.

  1. Reforming sewage sludge pyrolysis volatile with Fe-embedded char: Minimization of liquid product yield.

    Science.gov (United States)

    Yu, Guotao; Chen, Dezhen; Arena, Umberto; Huang, Zhen; Dai, Xiaohu

    2018-03-01

    Obtaining high quality syngas from sewage sludge (SS) means transferring a low-grade SS into a high-grade fuel or raw materials for chemical products. In this study, Fe is added to SS in form of Fe 2 (SO 4 ) 3 to produce an effective and self-sufficient catalyst in order to obtain more syngas and minimize liquid products from SS pyrolysis. The Fe-embedded sewage sludge chars (SSCs) were used as catalysts for volatile reforming at 600°C. It has been found that the gas yield increases from 15.9 to 35.8wt% of the SS and that of liquids decreases from 31.9 to 10.2wt% after volatile reforming with Fe-embedded SSC when Fe was added equal to 7 % in the dried SS. In addition, the content of nitrogen-containing compounds in the oily products decreased. After reforming with Fe-embedded SSC, the molar fractions of syngas combustible components, including H 2 , CH 4 and CO, increase, and the higher heating value of the syngas increased to 17.0MJ/Nm 3 from the original 12.5MJ/Nm 3 obtained from SS pyrolysis at 550°C. Moreover, the volatile reforming seems to reduce the level of some important syngas pollutants, like H 2 S, HCl and HCN, even though it was also observed an increase of the contents of SO 2 , NH 3 , NO 2, HCNO and N 2 O. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Testing for a Common Volatility Process and Information Spillovers in Bivariate Financial Time Series Models

    NARCIS (Netherlands)

    J. Chen (Jinghui); M. Kobayashi (Masahito); M.J. McAleer (Michael)

    2016-01-01

    textabstractThe paper considers the problem as to whether financial returns have a common volatility process in the framework of stochastic volatility models that were suggested by Harvey et al. (1994). We propose a stochastic volatility version of the ARCH test proposed by Engle and Susmel (1993),

  3. Process engineering versus product engineering - A case study on volatile organic compounds removal

    DEFF Research Database (Denmark)

    Coutinho, João A.P.; Vilela, T.; Pereira, P.

    2005-01-01

    Three solutions for removing the dangerous volatile organic compound (VOC) xylene from an industrial coating process are presented and compared. Two of them are based on classical process engineering principles, i.e., development of separation-cleaning methods such as incineration and adsorption...... to the problem-need specified in the beginning of the project, but producing a novel formulation (chemical product design) represents a method that results to a completely xylene-free process which is environmentally and economically more interesting than those generated via the more traditional process...

  4. New device for time-averaged measurement of volatile organic compounds (VOCs)

    Energy Technology Data Exchange (ETDEWEB)

    Santiago Sánchez, Noemí; Tejada Alarcón, Sergio; Tortajada Santonja, Rafael; Llorca-Pórcel, Julio, E-mail: julio.llorca@aqualogy.net

    2014-07-01

    Contamination by volatile organic compounds (VOCs) in the environment is an increasing concern since these compounds are harmful to ecosystems and even to human health. Actually, many of them are considered toxic and/or carcinogenic. The main sources of pollution come from very diffuse focal points such as industrial discharges, urban water and accidental spills as these compounds may be present in many products and processes (i.e., paints, fuels, petroleum products, raw materials, solvents, etc.) making their control difficult. The presence of these compounds in groundwater, influenced by discharges, leachate or effluents of WWTPs is especially problematic. In recent years, law has been increasingly restrictive with the emissions of these compounds. From an environmental point of view, the European Water Framework Directive (2000/60/EC) sets out some VOCs as priority substances. This binding directive sets guidelines to control compounds such as benzene, chloroform, and carbon tetrachloride to be at a very low level of concentration and with a very high frequency of analysis. The presence of VOCs in the various effluents is often highly variable and discontinuous since it depends on the variability of the sources of contamination. Therefore, in order to have complete information of the presence of these contaminants and to effectively take preventive measures, it is important to continuously control, requiring the development of new devices which obtain average concentrations over time. As of today, due to technical limitations, there are no devices on the market that allow continuous sampling of these compounds in an efficient way and to facilitate sufficient detection limits to meet the legal requirements which are capable of detecting very sporadic and of short duration discharges. LABAQUA has developed a device which consists of a small peristaltic pump controlled by an electronic board that governs its operation by pre-programming. A constant flow passes

  5. The lipoxygenase metabolic pathway in plants: potential for industrial production of natural green leaf volatiles

    Directory of Open Access Journals (Sweden)

    Gigot, C.

    2010-01-01

    Full Text Available Lipoxygenase enzymatic pathway is a widely studied mechanism in the plant kingdom. Combined actions of three enzymes: lipase, lipoxygenase (LOX and hydroperoxide lyase (HPL convert lipidic substrates such as C18:2 and C18:3 fatty acids into short chain volatiles. These reactions, triggered by cell membrane disruptions, produce compounds known as Green Leaf Volatiles (GLVs which are C6 or C9-aldehydes and alcohols. These GLVs are commonly used as flavors to confer a fresh green odor of vegetable to food products. Therefore, competitive biocatalytic productions have been developed to meet the high demand in these natural flavors. Vegetable oils, chosen for their lipidic acid profile, are converted by soybean LOX and plant HPL into natural GLVs. However this second step of the bioconversion presents low yield due to the HPL instability and the inhibition by its substrate. This paper will shortly describe the different enzymes involved in this bioconversion with regards to their chemical and enzymatic properties. Biotechnological techniques to enhance their production potentialities will be discussed along with their implication in a complete bioprocess, from the lipid substrate to the corresponding aldehydic or alcoholic flavors.

  6. Volatile profile, lipid oxidation and protein oxidation of irradiated ready-to-eat cured turkey meat products

    International Nuclear Information System (INIS)

    Feng, Xi; Ahn, Dong Uk

    2016-01-01

    Irradiation had little effects on the thiobarbituric acid reactive substances (TBARS) values in ready-to-eat (RTE) turkey meat products, while it increased protein oxidation at 4.5 kGy. The volatile profile analyses indicated that the amount of sulfur compounds increased linearly as doses increased in RTE turkey meat products. By correlation analysis, a positive correlation was found between benzene/ benzene derivatives and alcohols with lipid oxidation, while aldehydes, ketones and alkane, alkenes and alkynes were positively correlated with protein oxidation. Principle component analysis showed that irradiated meat samples can be discriminated by two categories of volatile compounds: Strecker degradation products and radiolytic degradation products. The cluster analysis of volatile data demonstrated that low-dose irradiation had minor effects on the volatile profile of turkey sausages (<1.5 kGy). However, as the doses increased, the differences between the irradiated and non-irradiated cured turkey products became significant. - Highlights: • Irradiation had little effects on lipid oxidation of ready-to-eat cured turkey. • 4.5 kGy irradiation increased protein oxidation. • Irradiated samples were isolated due to Strecker/radiolytic degradation products. • 1.5 kGy irradiation had limited effects on the volatile profile of turkey sausages. • Dimethyl disulfide can be used as a potential marker for irradiated meat products.

  7. Chemical diversity of microbial volatiles and their potential for plant growth and productivity

    Directory of Open Access Journals (Sweden)

    CHIDANANDA NAGAMANGALA KANCHISWAMY

    2015-03-01

    Full Text Available Microbial volatile organic compounds (MVOCs are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs and their potential physiological effects on crops and analyze potential and actual limitations for MVOC use as a sustainable strategy for improving productivity and reducing pesticide use.

  8. New device for time-averaged measurement of volatile organic compounds (VOCs).

    Science.gov (United States)

    Santiago Sánchez, Noemí; Tejada Alarcón, Sergio; Tortajada Santonja, Rafael; Llorca-Pórcel, Julio

    2014-07-01

    Contamination by volatile organic compounds (VOCs) in the environment is an increasing concern since these compounds are harmful to ecosystems and even to human health. Actually, many of them are considered toxic and/or carcinogenic. The main sources of pollution come from very diffuse focal points such as industrial discharges, urban water and accidental spills as these compounds may be present in many products and processes (i.e., paints, fuels, petroleum products, raw materials, solvents, etc.) making their control difficult. The presence of these compounds in groundwater, influenced by discharges, leachate or effluents of WWTPs is especially problematic. In recent years, law has been increasingly restrictive with the emissions of these compounds. From an environmental point of view, the European Water Framework Directive (2000/60/EC) sets out some VOCs as priority substances. This binding directive sets guidelines to control compounds such as benzene, chloroform, and carbon tetrachloride to be at a very low level of concentration and with a very high frequency of analysis. The presence of VOCs in the various effluents is often highly variable and discontinuous since it depends on the variability of the sources of contamination. Therefore, in order to have complete information of the presence of these contaminants and to effectively take preventive measures, it is important to continuously control, requiring the development of new devices which obtain average concentrations over time. As of today, due to technical limitations, there are no devices on the market that allow continuous sampling of these compounds in an efficient way and to facilitate sufficient detection limits to meet the legal requirements which are capable of detecting very sporadic and of short duration discharges. LABAQUA has developed a device which consists of a small peristaltic pump controlled by an electronic board that governs its operation by pre-programming. A constant flow passes

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

    Science.gov (United States)

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

    2014-07-01

    Space weathering is a generic term for the effects on atmosphereless solid bodies in the solar system from a range of processes associated with direct exposure to the space environment. These include impact processes (shock, vaporization, fragmentation, heating, melting, and ejecta formation), radiation damage (from galactic and solar cosmic rays), solar-wind effects (irradiation, ion implantation, and sputtering), and the chemical reactions driven by these processes. The classic example of space weathering is the formation of the lunar spectral red slope associated with the production of nanophase Fe (npFe0) in the dusty lunar regolith (C.R. Chapman, 2004, Annual Review of Earth & Planet. Sci. 32, C.M. Pieters, 2000, MAPS 35). Similar npFe0 has been recovered from asteroid (25143) Itokawa and some asteroid classes do exhibit modest spectral red slopes (T. Noguchi, 2011, Science 333). Space weathering can be thought of as driven by a combination of the chemical environment of space (hard vacuum, low oxygen fugacity, solar-wind implantation of hydrogen) along with thermal energy supplied by micrometeorite impacts. The forward modeling of space weathering as thermodynamically-driven decomposition of common rock-forming minerals suggests the production of a range of daughter products: (1) The silicate products typically lose oxygen, other volatile elements (i.e., sulfur and sodium), and metallic cations, producing minerals that are typically more disordered and less optically active than the original parent materials. (2) The decomposed metallic cations form in nano-sized blebs including npFe0, on the surfaces or in condensing rims of mineral grains. This creates a powerful optical component as seen in the lunar red slope. Surfaces with exposed npFe0 are an ideal environment for catalyzing further reactions. (3) The liberated volatile elements and gases (O, S, Na) may form an observable exosphere (e.g., Moon and Mercury) and can either escape from the body or

  10. Microbial production of volatile sulphur compounds in the large intestine of pigs fed two different diets.

    Science.gov (United States)

    Poulsen, H V; Jensen, B B; Finster, K; Spence, C; Whitehead, T R; Cotta, M A; Canibe, N

    2012-07-01

      To investigate the production of volatile sulphur compounds (VSC) in the segments of the large intestine of pigs and to assess the impact of diet on this production.   Pigs were fed two diets based on either wheat and barley (STD) or wheat and dried distillers grains with solubles (DDGS). Net production of VSC and potential sulphate reduction rate (SRR) (sulphate saturated) along the large intestine were determined by means of in vitro incubations. The net production rate of hydrogen sulphide and potential SRR increased from caecum towards distal colon and were significantly higher in the STD group. Conversely, the net methanethiol production rate was significantly higher in the DDGS group, while no difference was observed for dimethyl sulphide. The number of sulphate-reducing bacteria and total bacteria were determined by quantitative PCR and showed a significant increase along the large intestine, whereas no diet-related differences were observed.   VSC net production varies widely throughout the large intestine of pigs and the microbial processes involved in this production can be affected by diet.   This first report on intestinal production of all VSC shows both spatial and dietary effects, which are relevant to both bowel disease- and odour mitigation research. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  11. Time-Related Changes in Volatile Compounds during Fermentation of Bulk and Fine-Flavor Cocoa (Theobroma cacao Beans

    Directory of Open Access Journals (Sweden)

    Juan Manuel Cevallos-Cevallos

    2018-01-01

    Full Text Available Chocolate is one of the most consumed foods worldwide and cacao fermentation contributes to the unique sensory characteristics of chocolate products. However, comparative changes in volatiles occurring during fermentation of Criollo, Forastero, and Nacional cacao—three of the most representative cultivars worldwide—have not been reported. Beans of each cultivar were fermented for five days and samples were taken every 24 hours. Volatiles from each sample were adsorbed into a solid phase microextraction fiber and analyzed by gas chromatography-mass spectrometry. Aroma potential of each compound was determined using available databases. Multivariate data analyses showed partial clustering of samples according to cultivars at the start of the fermentation but complete clustering was observed at the end of the fermentation. The Criollo cacao produced floral, fruity, and woody aroma volatiles including linalool, epoxylinalool, benzeneethanol, pentanol acetate, germacrene, α-copaene, aromadendrene, 3,6-heptanedione, butanal, 1-phenyl ethenone, 2-nonanone, and 2-pentanone. Nacional cacao produced fruity, green, and woody aroma volatiles including 2-nonanone, 3-octen-1-ol, 2-octanol acetate, 2-undecanone, valencene, and aromadendrene. The Forastero cacao yielded floral and sweet aroma volatiles such as epoxylinalool, pentanoic acid, benzeneacetaldehyde, and benzaldehyde. This is the first report of volatiles produced during fermentation of Criollo, Forastero, and Nacional cacao from the same origin.

  12. An evaluation of nodalization/decay heat/ volatile fission product release models in ISAAC code

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yong Mann; Park, Soo Yong; Kim, Dong Ha

    2003-03-01

    An ISAAC computer code, which was developed for a Level-2 PSA during 1995, has developed mainly with fundamental models for CANDU-specific severe accident progression and also the accident-analyzing experiences are limited to Level-2 PSA purposes. Hence the system nodalization model, decay model and volatile fission product release model, which are known to affect fission product behavior directly or indirectly, are evaluated to both enhance understanding for basic models and accumulate accident-analyzing experiences. As a research strategy, sensitivity studies of model parameters and sensitivity coefficients are performed. According to the results from core nodalization sensitivity study, an original 3x3 nodalization (per loop) method which groups horizontal fuel channels into 12 representative channels, is evaluated to be sufficient for an optimal scheme because detailed nodalization methods have no large effect on fuel thermal-hydraulic behavior, total accident progression and fission product behavior. As ANSI/ANS standard model for decay heat prediction after reactor trip has no needs for further model evaluation due to both wide application on accident analysis codes and good comparison results with the ORIGEN code, ISAAC calculational results of decay heat are used as they are. In addition, fission product revaporization in a containment which is caused by the embedded decay heat, is demonstrated. The results for the volatile fission product release model are analyzed. In case of early release, the IDCOR model with an in-vessel Te release option shows the most conservative results and for the late release case, NUREG-0772 model shows the most conservative results. Considering both early and late release, the IDCOR model with an in-vessel Te bound option shows mitigated conservative results.

  13. Warped product space-times

    Science.gov (United States)

    An, Xinliang; Wong, Willie Wai Yeung

    2018-01-01

    Many classical results in relativity theory concerning spherically symmetric space-times have easy generalizations to warped product space-times, with a two-dimensional Lorentzian base and arbitrary dimensional Riemannian fibers. We first give a systematic presentation of the main geometric constructions, with emphasis on the Kodama vector field and the Hawking energy; the construction is signature independent. This leads to proofs of general Birkhoff-type theorems for warped product manifolds; our theorems in particular apply to situations where the warped product manifold is not necessarily Einstein, and thus can be applied to solutions with matter content in general relativity. Next we specialize to the Lorentzian case and study the propagation of null expansions under the assumption of the dominant energy condition. We prove several non-existence results relating to the Yamabe class of the fibers, in the spirit of the black-hole topology theorem of Hawking–Galloway–Schoen. Finally we discuss the effect of the warped product ansatz on matter models. In particular we construct several cosmological solutions to the Einstein–Euler equations whose spatial geometry is generally not isotropic.

  14. Thermophysical modeling of volatile fission product release from a debris pool

    International Nuclear Information System (INIS)

    Yun, J. I.; Suh, K. Y.; Kang, C. S.

    1999-01-01

    A model is described for fission product release from the debris pool in the lower plenum of the reactor pressure vessel. In the pool, turbulent natural convection flow is formed due to homogeneous internal heat generation. Using the best-known correlations, heat transfer at the curved bottom and the top of the pool may be calculated. Volatile fission product gases in the pool nucleate and diffuse to bubbles. Both the homogeneous nucleation and heterogeneous nucleation are considered. The bubble nucleation, growth, coalescence and loss due to rise is modeled pursuant to bubble dynamics. If the pressure and temperature of the pool are very high, homogeneous nucleation that accounts for effect of decrease in the pool pressure can occur. The effect of the bubble-to-pool interfacial tension and the pool pressure on the nucleation rate is investigated in this work

  15. Bioelectrochemical recovery of waste-derived volatile fatty acids and production of hydrogen and alkali

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development...... of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode....... At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net...

  16. Effects of total replacement of soybean meal and corn on ruminal fermentation, volatile fatty acids, protozoa concentration, and gas production

    Directory of Open Access Journals (Sweden)

    A. Bahri

    2018-03-01

    Full Text Available The main purpose of this study is to evaluate the effect of total replacement of soybean meal and corn with triticale and faba bean or field pea on rumen fermentation, protozoa counts, and gas production of lactating ewes. A total of 30 Sicilo-Sarde ewes were randomly allocated into three groups and were fed 1.8 kg drymatter of oat hay plus 500 g of one of three concentrates: the first concentrate (CS was mainly composed of soybean meal, corn, and barley; the second (TFB was formed by triticale and faba bean; and the third (TFP was composed of triticale and field pea. The type of concentrate did not affect ruminal pH or ammonia nitrogen concentration (P  >  0.05. The individual concentrations of volatile fatty acids showed a significant interaction between the type of concentrate and sampling time (P  <  0.05, except for Butyric and Isobutyric acids. Within a post-feeding time, the pattern of evolution of total volatile fatty, acetic, and propionic acids differed significantly at 2 h post feeding (P  <  0.05, while butyric and valeric acid changed at 0 and 4 h post feeding. The type of concentrate affected the total number of ciliate protozoa and the Isotricha species (P  <  0.05, whereas Entodinium, Ophryoscolex, and Polyplastron were similar among concentrates (P  >  0.05. The cumulative gas production from the in vitro fermentation, the time of incubation, and their interaction was affected by concentrate (P  <  0.001. The substitution of soybean meal and corn in the concentrate with faba bean or field peas and triticale might maintain rumen parameters of dairy ewes.

  17. Extreme-Strike and Small-time Asymptotics for Gaussian Stochastic Volatility Models

    OpenAIRE

    Zhang, Xin

    2016-01-01

    Asymptotic behavior of implied volatility is of our interest in this dissertation. For extreme strike, we consider a stochastic volatility asset price model in which the volatility is the absolute value of a continuous Gaussian process with arbitrary prescribed mean and covariance. By exhibiting a Karhunen-Loève expansion for the integrated variance, and using sharp estimates of the density of a general second-chaos variable, we derive asymptotics for the asset price density for large or smal...

  18. Utilization of Volatile Fatty Acids from Microalgae for the Production of High Added Value Compounds

    Directory of Open Access Journals (Sweden)

    Angelina Chalima

    2017-10-01

    Full Text Available Volatile Fatty Acids (VFA are small organic compounds that have attracted much attention lately, due to their use as a carbon source for microorganisms involved in the production of bioactive compounds, biodegradable materials and energy. Low cost production of VFA from different types of waste streams can occur via dark fermentation, offering a promising approach for the production of biofuels and biochemicals with simultaneous reduction of waste volume. VFA can be subsequently utilized in fermentation processes and efficiently transformed into bioactive compounds that can be used in the food and nutraceutical industry for the development of functional foods with scientifically sustained claims. Microalgae are oleaginous microorganisms that are able to grow in heterotrophic cultures supported by VFA as a carbon source and accumulate high amounts of valuable products, such as omega-3 fatty acids and exopolysaccharides. This article reviews the different types of waste streams in concert with their potential to produce VFA, the possible factors that affect the VFA production process and the utilization of the resulting VFA in microalgae fermentation processes. The biology of VFA utilization, the potential products and the downstream processes are discussed in detail.

  19. Generalized Fractional Processes with Long Memory and Time Dependent Volatility Revisited

    Directory of Open Access Journals (Sweden)

    M. Shelton Peiris

    2016-09-01

    Full Text Available In recent years, fractionally-differenced processes have received a great deal of attention due to their flexibility in financial applications with long-memory. This paper revisits the class of generalized fractionally-differenced processes generated by Gegenbauer polynomials and the ARMA structure (GARMA with both the long-memory and time-dependent innovation variance. We establish the existence and uniqueness of second-order solutions. We also extend this family with innovations to follow GARCH and stochastic volatility (SV. Under certain regularity conditions, we give asymptotic results for the approximate maximum likelihood estimator for the GARMA-GARCH model. We discuss a Monte Carlo likelihood method for the GARMA-SV model and investigate finite sample properties via Monte Carlo experiments. Finally, we illustrate the usefulness of this approach using monthly inflation rates for France, Japan and the United States.

  20. Volatility behavior of visibility graph EMD financial time series from Ising interacting system

    Science.gov (United States)

    Zhang, Bo; Wang, Jun; Fang, Wen

    2015-08-01

    A financial market dynamics model is developed and investigated by stochastic Ising system, where the Ising model is the most popular ferromagnetic model in statistical physics systems. Applying two graph based analysis and multiscale entropy method, we investigate and compare the statistical volatility behavior of return time series and the corresponding IMF series derived from the empirical mode decomposition (EMD) method. And the real stock market indices are considered to be comparatively studied with the simulation data of the proposed model. Further, we find that the degree distribution of visibility graph for the simulation series has the power law tails, and the assortative network exhibits the mixing pattern property. All these features are in agreement with the real market data, the research confirms that the financial model established by the Ising system is reasonable.

  1. Volatile Fatty Acids Production from Codigestion of Food Waste and Sewage Sludge Based on β-Cyclodextrins and Alkaline Treatments.

    Science.gov (United States)

    Yang, Xue; Liu, Xiang; Chen, Si; Liu, Guangmin; Wu, Shuyan; Wan, Chunli

    2016-01-01

    Volatile fatty acids (VFAs) are preferred valuable resources, which can be produced from anaerobic digestion process. This study presents a novel technology using β -cyclodextrins ( β -CD) pretreatment integrated alkaline method to enhance VFAs production from codigestion of food waste and sewage sludge. Experiment results showed that optimized ratio of food waste to sewage sludge was 3 : 2 because it provided adequate organic substance and seed microorganisms. Based on this optimized ratio, the integrated treatment of alkaline pH 10 and β -CD addition (0.2 g/g TS) performed the best enhancement on VFAs production, and the maximum VFAs production was 8631.7 mg/L which was 6.13, 1.38, and 1.57 times higher than that of control, initial pH 10, and 0.2 g β -CD/g TS treatment, respectively. Furthermore, the hydrolysis rate of protein and polysaccharides was greatly improved in integration treatment, which was 1.18-3.45 times higher than that of other tests. Though the VFAs production and hydrolysis of polymeric organics were highly enhanced, the primary bacterial communities with different treatments did not show substantial differences.

  2. Volatile and non-volatile radiolysis products in irradiated multilayer coextruded food-packaging films containing a buried layer of recycled low-density polyethylene.

    Science.gov (United States)

    Chytiri, S; Goulas, A E; Badeka, A; Riganakos, K A; Kontominas, M G

    2005-12-01

    The effects of gamma-irradiation (5-60 kGy) on radiolysis products and sensory changes of experimental five-layer food-packaging films were determined. Films contained a middle buried layer of recycled low-density polyethylene (LDPE) comprising 25-50% by weight (bw) of the multilayer structure. Respective films containing 100% virgin LDPE as the buried layer were used as controls. Under realistic polymer/food simulant contact conditions during irradiation, a large number of primary and secondary radiolysis products (hydrocarbons, aldehydes, ketones, alcohols, carboxylic acids) were produced. These compounds were detected in the food simulant after contact with all films tested, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food preservation). The type and concentration of radiolysis products increased progressively with increasing dose. Generally, there were no significant differences in radiolysis products between samples containing a buried layer of recycled LDPE and those containing virgin LDPE (all absorbed doses), indicating the good barrier properties of external virgin polymer layers. Volatile and non-volatile compounds produced during irradiation affected the sensory properties of potable water after contact with packaging films. Taste transfer to water was observed mainly at higher doses and was more noticeable for multilayer structures containing recycled LDPE, even though differences were slight.

  3. A Hull and White Formula for a General Stochastic Volatility Jump-Diffusion Model with Applications to the Study of the Short-Time Behavior of the Implied Volatility

    Directory of Open Access Journals (Sweden)

    Elisa Alòs

    2008-01-01

    Full Text Available We obtain a Hull and White type formula for a general jump-diffusion stochastic volatility model, where the involved stochastic volatility process is correlated not only with the Brownian motion driving the asset price but also with the asset price jumps. Towards this end, we establish an anticipative Itô's formula, using Malliavin calculus techniques for Lévy processes on the canonical space. As an application, we show that the dependence of the volatility process on the asset price jumps has no effect on the short-time behavior of the at-the-money implied volatility skew.

  4. Time-related variation of volatile contents of Western Ghats volcanic formations, Deccan, India

    Science.gov (United States)

    Marzoli, Andrea; Callegaro, Sara; Baker, Don R.; De Min, Angelo; Renne, Paul R.

    2016-04-01

    Deccan volcanism in India covered more than 1 million square km and reached a maximum thickness of about 3 km, as presently preserved in the Western Ghats volcanic lava piles. Volcanic activity started at about 66.4 Ma (Jawhar formation) and ended at about 65.5 Ma (Mahabaleshwar unit; Renne et al., 2015). Deccan volcanism straddled the Cretaceous-Paleogene boundary (ca. 66.0 Ma) and possibly contributed to the end-Cretaceous mass extinction event through emission of gases such as SO2, CO2, Cl, F that may have triggered global climate changes. Severe pollution by volcanic gases is supported by the high S and Cl contents (up to 1400 and up to 900 ppm, respectively; Self et al., 2008) measured in a few olivine- and plagioclase-hosted melt inclusions from the Jawhar, Neral, and Thakurvadi Formations (early lava flows, ca. 66.3-66.4 ± 0.1 Ma; Renne et al., 2015) and by magmatic S contents (up to 1800 ppm; Callegaro et al., 2014) calculated from S measurements in clinopyroxenes from the Mahabaleshwar unit (ca. 65.5 ± 0.1; Schoene et al., 2015). Here, we present new analyses of S, Cl, and F, obtained by ion-probe and synchrotron light micro-fluorescence analyses on clinopyroxenes and plagioclase phenocrysts from ?al? lava flow units of the Western Ghats. The volatile contents of the host magmas have been calculated from recently published clinopyroxene/basalt partition coefficients. These new data will describe the time-related variation of volatile elements hosted and eventually emitted by Deccan lavas and shed light on their environmental impact. References: Callegaro S. et al. (2014). Geology 42, 895-898. Renne P.R. et al. (2015). Science 350, 76-78. Schoene B. et al. (2015). Science 347, 192-184. Self S. et al. (2008). Science 319, 1654-1657.

  5. Effects of different drying methods on the product quality and volatile compounds of whole shiitake mushrooms.

    Science.gov (United States)

    Tian, Yuting; Zhao, Yingting; Huang, Jijun; Zeng, Hongliang; Zheng, Baodong

    2016-04-15

    Various drying methods play important roles in the preservation of foods. However, how the different drying methods affect the quality of some foods is not clear. This paper evaluates the effects of hot air, vacuum, microwave, and microwave vacuum drying techniques on important qualities and volatile compounds of whole shiitake (Lentinus edodes) mushrooms. These four drying methods resulted in a significantly (pdried products. Microwave vacuum drying helped to maintain larger amounts of taste-active amino acids, and improved nutrient retention and color attributes. Furthermore, the uniform honeycomb network created by microwave vacuum drying along with a less collapsed structure of dried samples can be used to explain the observed high rehydration ratio. Therefore, microwave vacuum drying should be a potential method for obtaining high-quality dried mushrooms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Symptoms of mothers and infants related to total volatile organic compounds in household products.

    Science.gov (United States)

    Farrow, Alexandra; Taylor, Hazel; Northstone, Kate; Golding, Jean

    2003-10-01

    The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that approximated 6 mo of pregnancy and the infants' first 6 mo of life. This paper presents (a) the mothers' self-reports of the use of these products in their homes and (b) self-reported medical symptoms of mothers and infants postnatally. Higher TVOC levels were associated with air freshener and aerosol use. Infant diarrhea and earache were statistically significantly associated with air freshener use, and diarrhea and vomiting were significantly associated with aerosol use. Headache experienced by mothers 8 mo after birth was significantly associated with the use of air fresheners and aerosols; maternal depression was significantly associated with the use of air fresheners. The results of the study suggest a link between the use of products that raise indoor levels of TVOCs and an increased risk of certain symptoms among infants and their mothers.

  7. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

    Science.gov (United States)

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-06-09

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget.

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

    CERN Document Server

    Duellmann, C E; Eichler, R; Gäggeler, H W; Jost, D T; Piguet, D; Türler, A

    2002-01-01

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

  9. 'Scarlett Spur Red Delicious' apple volatile production accompanying physiological disorder development during low pO2 controlled atmosphere storage.

    Science.gov (United States)

    Lumpkin, Christie; Fellman, John K; Rudell, David R; Mattheis, James

    2014-02-19

    Apple (Malus domestica Borkh.) fruit volatile production is regulated by a variety of factors including low oxygen storage conditions. This study examined the impact of low pO2 controlled atmospheres on 'Scarlett Spur Red Delicious' apple volatile production and disorder development. Accumulation of apple volatile compounds was characterized during long-term cold storage at 0.5 °C in air or low pO2 (0.3, 0.8, or 1.5 kPa) with 1 kPa CO2. Volatile accumulation differed quantitatively with pO2 as acetaldehyde, ethanol, and ethyl ester accumulation increased with decreased pO2 during the first weeks in storage. Differences in volatile accumulation among atmospheres were evident through 6 months. The rate of ethanol accumulation increased with decreased pO2 and could potentially be used to monitor low O2 stress. Incidence of low oxygen disorders after 9 months was highest in fruit held at the lowest pO2. The sesquiterpene α-farnesene was not detected throughout the storage period.

  10. Anaerobic digestion of tuna waste for the production of volatile fatty acids.

    Science.gov (United States)

    Bermúdez-Penabad, Noela; Kennes, Christian; Veiga, Maria C

    2017-10-01

    Fish canning industries generate a significant amount of solid waste that can be digested anaerobically into volatile fatty acids (VFA). The aim of this research was to study the effect of various pHs, ranging from 5.0 to 10.0, and percentage of total solids on the anaerobic digestion of tuna waste into VFA, both in batch assays and continuous reactor. The production of VFA was affected by pH and was significantly higher under alkaline conditions. At pH 8.0, the VFA production reached 30,611mgCOD/L. The VFA mainly consisted of acetic, propionic, n-butyric and i-valeric acids. Acetic acid was the main product at all the pHs tested. In terms of total solids (TS) the best results were obtained with 2.5% total solids, reaching 0.73gCOD VFA /gCOD waste . At higher TS concentrations (5 and 8% TS) lower yields were reached probably due to inhibition at high VFA concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Influence of gender and stress on the volatile sulfur compounds and stress biomarkers production.

    Science.gov (United States)

    Lima, P O; Calil, C M; Marcondes, F K

    2013-05-01

    Stress and menstrual cycle have been described as factors influencing bad breath, as they can alter oral homeostasis and contribute to the production of volatile sulfur compounds (VSC). Considering that the experimenter's and volunteer's gender may influence the volunteer's responses to stress, the aim of this work was to evaluate the influence of stress and gender on the production of VSC and salivary biomarkers. The experimental acute stress was induced by the Video-Recorded Stroop Color-Word Test (VRSCWT). The VSC, salivary proteins, and cardiovascular parameters were measured before and after VRSCWT. The VRSCWT induced significant increase in total VSC, hydrogen sulfide, and blood pressure values in men and women. Women presented higher values of both these compounds than men. The increase in systolic blood pressure was more pronounced when subjects were evaluated by an experimenter of the opposite gender. When women were evaluated by a member of the opposite gender, they showed significant increases in salivary alpha-amylase and cortisol compared with baseline values. Thus, the results showed that VRSCWT induced acute stress, which increased VSC production, and these effects were shown to be influenced by the gender. © 2012 John Wiley & Sons A/S.

  12. Plant volatile aldehydes as natural insecticides against stored-product beetles.

    Science.gov (United States)

    Hubert, Jan; Münzbergová, Zuzana; Santino, Angelo

    2008-01-01

    Infestation by stored-product pests causes serious losses in food and feed commodities. Among possible strategies against these pests, which aim to reduce the use of synthetic insecticides, including fumigants, natural insecticides produced by plants represent one of the most promising approaches for their ecochemical control. Three six-carbon and nine-carbon aldehydes, natural plant volatiles produced by the plant lipoxygenase pathway, were tested for their insecticidal activity against five species of stored-product beetles in feeding, fumigation and combined bioassays. The compounds (2E,6Z)-nonadienal, (2E)-nonenal and (2E)-hexenal were incorporated into feeding discs in feeding bioassays or evaporated from filter paper in closed glass chambers in fumigation tests. Beetle sensitivity to aldehydes differed according to the different treatments. The highest activity was obtained by (2E)-hexenal in fumigation tests, with the LC(50) ranging from 4 to 26 mg L(-1), while (2E, 6Z)-nonadienal was the most effective in feeding tests, giving LD(50)s ranging from 0.44 to 2.76 mg g(-1) when applied to feeding discs. Fumigation tests in the presence of wheat grains confirmed that (2E)-hexenal was the most effective compound, with a calculated LC(99) ranging from 33 to 166 mg L(-1). The results of both feeding and fumigation tests indicated that natural plant aldehydes are potential candidates to control stored-product beetles.

  13. Implied Volatility and Rebalancing Timing: Market cycles and the relationship between implied volatility indices and stock index returns.

    OpenAIRE

    Holst, Niklas; Rønning, Harald

    2017-01-01

    Master's thesis in Finance This paper studies market timing based upon the level of the VIX and compares VIX based portfolio rotations with modern rebalancing practices. The thesis analyses the outcomes of the different rebalancing and trading strategies, and compare them through different performance measures. The study finds that on average, rebalancing strategies based on the level of the VIX does not have significant positive returns compared to the standard dynamic rebalancing scheme ...

  14. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    NARCIS (Netherlands)

    Os, van G.J.; Agtmaal, van M.; Hol, G.; Hundscheid, M.P.J.; Runia, W.T.; Hordijk, C.; Boer, de W.

    2015-01-01

    There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial

  15. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    NARCIS (Netherlands)

    van Agtmaal, Maaike; van Os, Gera; Hol, Gera; Hundscheid, M.P.J.; Runia, Willemien; Hordijk, Cees; De Boer, Wietse

    2015-01-01

    BACKGROUND: There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil

  16. Herbivory induces systemic production of plant volatiles that attract predators of the herbivore: extraction of endogenous elicitor.

    NARCIS (Netherlands)

    Dicke, M.; Baarlen, van P.; Wessels, R.; Dijkman, H.

    1993-01-01

    It was previously shown that in response to infestation by spider mites (Tetranychus urticae), lima bean plants produce a volatile herbivoreinduced synomone that attracts phytoseiid mites (Phytoseiulus persimilis) that are predators of the spider mites. The production of predator-attracting

  17. Quantitative and qualitative sensing techniques for biogenic volatile organic compounds and their oxidation products.

    Science.gov (United States)

    Kim, Saewung; Guenther, Alex; Apel, Eric

    2013-07-01

    The physiological production mechanisms of some of the organics in plants, commonly known as biogenic volatile organic compounds (BVOCs), have been known for more than a century. Some BVOCs are emitted to the atmosphere and play a significant role in tropospheric photochemistry especially in ozone and secondary organic aerosol (SOA) productions as a result of interplays between BVOCs and atmospheric radicals such as hydroxyl radical (OH), ozone (O3) and NOX (NO + NO2). These findings have been drawn from comprehensive analysis of numerous field and laboratory studies that have characterized the ambient distribution of BVOCs and their oxidation products, and reaction kinetics between BVOCs and atmospheric oxidants. These investigations are limited by the capacity for identifying and quantifying these compounds. This review highlights the major analytical techniques that have been used to observe BVOCs and their oxidation products such as gas chromatography, mass spectrometry with hard and soft ionization methods, and optical techniques from laser induced fluorescence (LIF) to remote sensing. In addition, we discuss how new analytical techniques can advance our understanding of BVOC photochemical processes. The principles, advantages, and drawbacks of the analytical techniques are discussed along with specific examples of how the techniques were applied in field and laboratory measurements. Since a number of thorough review papers for each specific analytical technique are available, readers are referred to these publications rather than providing thorough descriptions of each technique. Therefore, the aim of this review is for readers to grasp the advantages and disadvantages of various sensing techniques for BVOCs and their oxidation products and to provide guidance for choosing the optimal technique for a specific research task.

  18. Occurrence of volatile and non-volatile N-nitrosamines in processed meat products and the role of heat treatment

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Duedahl-Olesen, Lene; Granby, Kit

    2015-01-01

    -nitrosoproline (NPRO), N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA) and N-nitrosomethylaniline (NMA) depending on the type of product and/or the heat treatment. The levels of the NVNA, NTCA and N-nitroso-2-methyl-thiazolidine 4-carboxylic acid (NMTCA) decreased after frying...

  19. Improving production of volatile fatty acids from food waste fermentation by hydrothermal pretreatment.

    Science.gov (United States)

    Yin, Jun; Wang, Kun; Yang, Yuqiang; Shen, Dongsheng; Wang, Meizhen; Mo, Han

    2014-11-01

    Food waste (FW) was pretreated by a hydrothermal method and then fermented for volatile fatty acid (VFAs) production. The soluble substance in FW increased after hydrothermal pretreatment (⩽200 °C). Higher hydrothermal temperature would lead to mineralization of the organic compounds. The optimal temperature for organic dissolution was 180 °C, at which FW dissolved 42.5% more soluble chemical oxygen demand than the control. VFA production from pretreated FW fermentation was significantly enhanced compared with the control. The optimal hydrothermal temperature was 160 °C with a VFA yield of 0.908 g/g VSremoval. Butyrate and acetate were the prevalent VFAs followed by propionate and valerate. FW fermentation was inhibited after 200 °C pretreatment. The VFAs were extracted from the fermentation broth by liquid-liquid extraction. The VFA recovery was 50-70%. Thus, 0.294-0.411 g VFAs could be obtained per gram of hydrothermally pretreated FW (in dry weight) by this method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Effects of stress hormones on the production of volatile sulfur compounds by periodontopathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Caroline Morini Calil

    2014-06-01

    Full Text Available Little is known about the effects of stress hormones on the etiologic agents of halitosis. Thus, the aim of this study was to evaluate in vitro the effects of adrenaline (ADR, noradrenaline (NA and cortisol (CORT on bacteria that produce volatile sulfur compounds (VSC, the major gases responsible for bad breath. Cultures of Fusobacterium nucleatum (Fn, Porphyromonas endodontalis (Pe, Prevotella intermedia (Pi and Porphyromonas gingivalis (Pg were exposed to 50 µM ADR, NA and CORT or equivalent volumes of sterile water as controls for 12 and 24 h. Growth was evaluated based on absorbance at 660 nm. Portable gas chromatography was used to measure VSC concentrations. Kruskal-Wallis and the Dunn post-hoc test were used to compare the groups. For Fn, ADR, NA and CORT significantly reduced bacterial growth after 12 h and 24 h (p 0.05. In the Pi cultures, ADR, NA and CORT increased H2S (p < 0.05. Catecholamines and cortisol can interfere with growth and H2S production of sub-gingival species in vitro. This process appears to be complex and supports the association between stress and the production of VSC.

  1. 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.

  2. Herbivory by a Phloem-feeding insect inhibits floral volatile production.

    Directory of Open Access Journals (Sweden)

    Martin Pareja

    Full Text Available There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

  3. Herbivory by a Phloem-feeding insect inhibits floral volatile production.

    Science.gov (United States)

    Pareja, Martin; Qvarfordt, Erika; Webster, Ben; Mayon, Patrick; Pickett, John; Birkett, Michael; Glinwood, Robert

    2012-01-01

    There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

  4. 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.

  5. Influence of carbon and nitrogen source on production of volatile fragrance and flavour metabolites by the yeast Kluyveromyces marxianus.

    Science.gov (United States)

    Gethins, Loughlin; Guneser, Onur; Demirkol, Aslı; Rea, Mary C; Stanton, Catherine; Ross, R Paul; Yuceer, Yonca; Morrissey, John P

    2015-01-01

    The yeast Kluyveromyces marxianus produces a range of volatile molecules with applications as fragrances or flavours. The purpose of this study was to establish how nutritional conditions influence the production of these metabolites. Four strains were grown on synthetic media, using a variety of carbon and nitrogen sources and volatile metabolites analysed using gas chromatography-mass spectrometry (GC-MS). The nitrogen source had pronounced effects on metabolite production: levels of the fusel alcohols 2-phenylethanol and isoamyl alcohol were highest when yeast extract was the nitrogen source, and ammonium had a strong repressing effect on production of 2-phenylethyl acetate. In contrast, the nitrogen source did not affect production of isoamyl acetate or ethyl acetate, indicating that more than one alcohol acetyl transferase activity is present in K. marxianus. Production of all acetate esters was low when cells were growing on lactose (as opposed to glucose or fructose), with a lower intracellular pool of acetyl CoA being one explanation for this observation. Bioinformatic and phylogenetic analysis of the known yeast alcohol acetyl transferases ATF1 and ATF2 suggests that the ancestral protein Atf2p may not be involved in synthesis of volatile acetate esters in K. marxianus, and raises interesting questions as to what other genes encode this activity in non-Saccharomyces yeasts. Identification of all the genes involved in ester synthesis will be important for development of the K. marxianus platform for flavour and fragrance production. Copyright © 2014 John Wiley & Sons, Ltd.

  6. TIME-VARYING BETA AND VOLATILITY IN THE KUALA LUMPUR STOCK EXCHANGE

    Directory of Open Access Journals (Sweden)

    Mansor Ibrahim

    2004-01-01

    Full Text Available The paper analyzes the relationship between beta risk and aggregate market volatility for 12sized-based portfolios for the case of Malaysia using daily data from January 1988 to December 2000. The analysis is conducted for the entire sample as well as various sub-samples corresponding to (ithe upward trend in the market from January 1988-December 1992; (ii the huge influx of portfolio investments from January 1993-June 1997, and (Hi the Asian crisis and its aftermath from July 1997-December 2000. The results generally suggest instability in beta risk due to its significant response to aggregate market volatility. Additionally, we also note that the direction of relationship between beta risk and market volatility seems to depend on stock market conditions or sub-samples used. Namely, beta risk seems to decrease with increasing market volatility for the whole sample as well as the first and the third sub-samples. However, for the second sub-sample, their relationship turns to be positive. Lastly, the author have evidence for the Malaysian case that size does not play significant role in the way beta risk responds to aggregate market volatility. These results have important implications for investment decisions as well as for event analyses employing the market model to generate abnormal returns.

  7. 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.

  8. Phenolic carbonyls undergo rapid aqueous photodegradation to form low-volatility, light-absorbing products

    Science.gov (United States)

    Smith, Jeremy D.; Kinney, Haley; Anastasio, Cort

    2016-02-01

    We investigated the aqueous photochemistry of six phenolic carbonyls - vanillin, acetovanillone, guaiacyl acetone, syringaldehyde, acetosyringone, and coniferyl aldehyde - that are emitted from wood combustion. The phenolic carbonyls absorb significant amounts of solar radiation and decay rapidly via direct photodegradation, with lifetimes (τ) of 13-140 min under Davis, CA winter solstice sunlight at midday (solar zenith angle = 62°). The one exception is guaiacyl acetone, where the carbonyl group is not directly connected to the aromatic ring: This species absorbs very little sunlight and undergoes direct photodegradation very slowly (τ > 103 min). We also found that the triplet excited states (3C*) of the phenolic carbonyls rapidly oxidize syringol (a methoxyphenol without a carbonyl group), on timescales of 1-5 h for solutions containing 5 μM phenolic carbonyl. The direct photodegradation of the phenolic carbonyls, and the oxidation of syringol by 3C*, both efficiently produce low volatility products, with SOA mass yields ranging from 80 to 140%. Contrary to most aliphatic carbonyls, under typical fog conditions we find that the primary sink for the aromatic phenolic carbonyls is direct photodegradation in the aqueous phase. In areas of significant wood combustion, phenolic carbonyls appear to be small but significant sources of aqueous SOA: over the course of a few hours, nearly all of the phenolic carbonyls will be converted to SOA via direct photodegradation, enhancing the POA mass from wood combustion by approximately 3-5%.

  9. Evaporation release behavior of volatile fission products from liquid sodium pool to the inert cover gas

    Energy Technology Data Exchange (ETDEWEB)

    Nakagiri, T; Miyahara, S [Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corp., Oaraimachi, Ibaraki (Japan)

    1996-12-01

    In fuel failure of sodium cooled fast breeder reactors, released volatile fission products (VFPs) such as iodine and cesium from the fuel will be dissolved into the liquid sodium coolant and transferred to the cover vaporization. In the cover gas system of the reactor, natural convection occurs due to temperature differences between the sodium pool and the gas phase. The release rates of VFPs together with sodium vaporization are considered to be controlled by the convection. In this study, three analytical models are developed and examined to calculate the transient release rates using the equilibrium partition coefficients of VFPs. The calculated release rates are compared with experimental results for sodium and sodium iodide. The release rate of sodium is closest to the calculation by the heterogeneous nucleation theory. The release rate of sodium iodide obtained from the experiment is between the release rates calculated by the model based on heat-and-mass transfer analogy and the Hill`s theory. From this study, it is confirmed that the realistic release rate of sodium is able to be calculated by the model based on the heterogeneous nucleation theory. The conservative release rate of sodium iodide is able to be calculated by the model based on the Hill`s theory using the equilibrium partition coefficient of sodium iodide. (author) 7 figs., 1 tab., 3 refs.

  10. Measurement of Gas and Volatile Elements Production Cross Section in a Molten Lead-Bismuth Target

    CERN Multimedia

    2002-01-01

    MEGAPIE is a project for a 1 MW liquid PbBi spallation source, to be built at the SINQ facility at the Paul Scherrer Institut, which will be an important step in the roadmap towards the demonstration of the ADS concept and high power molten metal targets in general. In the design and construction of such a challenging project it is extremely important to evaluate the amount and type of gas and volatile elements which will be produced, for a reliable and safe operation of the experiment. Both stable (H, $^{4}$He and other noble gases) and radioactive isotopes are of interest. Currently, different design options are under consideration to deal with the gas produced during operation. \\\\ For a correct estimation of the production cross sections, a measurement with a liquid PbBi target and a proton beam of energy close to the one of MEGAPIE (575 MeV) is necessary. We would like to use the ISOLDE facility, which offers the unique opportunity via its mass spectrometric analysis of the elements present in the gas pha...

  11. Multifractals in Western Major STOCK Markets Historical Volatilities in Times of Financial Crisis

    Science.gov (United States)

    Lahmiri, Salim

    In this paper, the generalized Hurst exponent is used to investigate multifractal properties of historical volatility (CHV) in stock market price and return series before, during and after 2008 financial crisis. Empirical results from NASDAQ, S&P500, TSE, CAC40, DAX, and FTSE stock market data show that there is strong evidence of multifractal patterns in HV of both price and return series. In addition, financial crisis deeply affected the behavior and degree of multifractality in volatility of Western financial markets at price and return levels.

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

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2009-06-01

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

  13. Torrefaction of agricultural by-products: Effects of temperature and time on energy yields

    Science.gov (United States)

    Agricultural by-products, such as apple, grape, olive, and tomato pomaces as well as almond and walnut shells, were torrefied at different temperatures and times. Torrefaction of biomass involves heating in an inert atmosphere to remove volatile components for improved grindability and increased ene...

  14. Safety aspects of targets for ADTT: Activity, volatile products, residual heat release

    International Nuclear Information System (INIS)

    Gai, E.V.; Ignatyuk, A.V.; Lunev, V.P.; Shubin, Yu.N.

    1999-01-01

    Safety aspects of heavy metal liquid targets for the accelerator driven systems connected with the activity accumulation and residual energy release due to the irradiation with high energy proton beam are discussed. The results obtained for the lead-bismuth target that are under construction in IPPE now in the frame of ISTC Project No. 559 are briefly presented. The calculations and the analysis of the accumulation of the spallation reaction products, activity and energy release at various moments after the accelerator shutdown are presented. The concentrations of the reaction products, the total and partial activities, the activities of volatile products are determined. The contributions of the short-lived nuclides important for the prediction of the facility behaviour in regimes with the accelerator beam trips. The calculations and analysis of the residual energy release due to different decay type have been performed. The conclusions are as follows. The obtained results showed that long lived radioactivity accumulates mainly due to primary nuclear reactions. Secondary reactions are responsible for the production of small number of long-lived isotopes Bi-207, Po-210 and some others, being generated by radiative capture of low energy neutrons. It is possible to make a conclusion that neutrons in the energy range 20 - 800 MeV and protons with energy above 100 MeV give main contribution to the total activity generation although these parts of spectra inside the target give comparatively small contribution to the total flux. The correct consideration of short-lived nuclides contribution is the main problem in the analysis of the target behaviour in the case of short accelerator shutdowns. They make the determining contribution to the both activity and the heat release at the first moments after the accelerator shutdown, creating the intermediate links and additional channels for the long-lived nuclides accumulation chains. The strong dependence of calculated

  15. A discrete-time two-factor model for pricing bonds and interest rate derivatives under random volatility

    OpenAIRE

    Heston, Steven L.; Nandi, Saikat

    1999-01-01

    This paper develops a discrete-time two-factor model of interest rates with analytical solutions for bonds and many interest rate derivatives when the volatility of the short rate follows a GARCH process that can be correlated with the level of the short rate itself. Besides bond and bond futures, the model yields analytical solutions for prices of European options on discount bonds (and futures) as well as other interest rate derivatives such as caps, floors, average rate options, yield curv...

  16. Is Solid Phase Microextraction (SPME) an appropriate method for extraction of volatile oxidation products from complex food systems

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Horn, Anna Frisenfeldt; Lu, Henna Fung Sieng

    Volatile secondary lipid oxidation products can be identified and quantified by GC-FID or GC-MS. An extraction step is, however, needed before GC analysis. A range of different extraction methods are available such as static headspace, dynamic headspace and SPME. Each of these methods has its...... advantages and drawbacks. Among the advantages of the SPME method are its high sensitivity compared to static headspace and that it is less laborious than the dynamic headspace method. For these reasons, the use of SPME has increased in both academia and industry during the last decade. The extraction...... for analysis of lipid oxidation during storage of complex food matrices. Examples on how uncontrollable factors have affected results obtained with the SPME method in the authors’ lab will be given and the appropriateness of the SPME method for the analysis of volatile oxidation products in selected food...

  17. Solid phase microextraction (SPME) for extraction of volatile oxidation products from complex food systems – Pros and cons

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Horn, Anna Frisenfeldt; Lu, Henna Fung Sieng

    Volatile secondary lipid oxidation products can be identified and quantified by GC-FID or GC-MS. An extraction step is, however, needed before GC analysis. A range of different extraction methods are available such as static headspace, dynamic headspace and SPME. Each of these methods has its...... advantages and drawbacks. Among the advantages of the SPME method are its high sensitivity compared to static headspace and that it is less laborious than the dynamic headspace method. For these reasons, the use of SPME has increased in both academia and industry during the last decade. The extraction...... for analysis of lipid oxidation during storage of complex food matrices. Examples on how uncontrollable factors have affected results obtained with the SPME method in the authors’ lab will be given and the appropriateness of the SPME method for the analysis of volatile oxidation products in selected food...

  18. Worker's perceptions of time, time-use-attitudes and productivity

    OpenAIRE

    E. Ben-Baruch; C. P. H. Myburgh; E. C. Anderssen

    1991-01-01

    Decreasing productivity and increasing wage demands are singled out as being crucial problems facing the economy of South Africa. Changes in the time perceptions and time-use-attitudes of workers could play a decisive role in increasing productivity. The relationships between time perception, needs, motivation and productivity are analysed. Culture, tradition, economy, and environment lend a specific significance to these variables. Workers in a technological society should be guided to adapt...

  19. GC-FTIR-MS analysis of volatile products in the radiolysis of nitrobenzene-carbon tetrachloride solution

    International Nuclear Information System (INIS)

    Kuruc, J.; Sahoo, M.K.; Kuran, P.

    1993-01-01

    A number of volatile products formed in the gamma-radiolysis of nitrobenzene-carbon tetrachlorine solution have been identified using a GC-FTIR-MS technique. The conditions for separation of the products have been described. HCL, COCl 2 chlorobenzene, chloro- and dichloronitrobenzene, isomeric di-, tri- and tetrachlorobenzene, hexachloroethane, tetrachloroethylene, α,α,α-trichloromethylbenzene, chloro-and dichloroisocyanatobenzene, and other chloroderivatives are among the important products formed. Ipso-substituion of the nitro group as well as hydrogen atom by chlorine atom and Cl 3 free radical is noticed. It is proposed that chloroisocyanatobenzene is formed as the result of interaction of dichlorocarbene and nitrobenzene. (orig.)

  20. Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

    Science.gov (United States)

    Hopkins, Frances; Bell, Thomas; Yang, Mingxi

    2017-04-01

    Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

  1. Microbial Community Pathways for the Production of Volatile Fatty Acids From CO2 and Electricity

    Directory of Open Access Journals (Sweden)

    Jorge Wenzel

    2018-04-01

    Full Text Available This study aims at elucidating the metabolic pathways involved in the production of volatile fatty acids from CO2 and electricity. Two bioelectrochemical systems (BES were fed with pure CO2 (cells A and B. The cathode potential was first poised at −574 mV vs. standard hydrogen electrode (SHE and then at −756 mV vs. SHE in order to ensure the required reducing power. Despite applying similar operation conditions to both BES, they responded differently. A mixture of organic compounds (1.87 mM acetic acid, 2.30 mM formic acid, 0.43 mM propionic acid, 0.15 mM butyric acid, 0.55 mM valeric acid, and 0.62 mM ethanol was produced in cell A while mainly 1.82 mM acetic acid and 0.23 mM propionic acid were produced in cell B. The microbial community analysis performed by 16S rRNA gene pyrosequencing showed a predominance of Clostridium sp. and Serratia sp. in cell A whereas Burkholderia sp. and Xanthobacter sp. predominated in cell B. The coexistence of three metabolic pathways involved in carbon fixation was predicted. Calvin cycle was predicted in both cells during the whole experiment while Wood-Ljungdahl and Arnon-Buchanan pathways predominated in the period with higher coulombic efficiency. Metabolic pathways which transform organic acids into anabolic intermediaries were also predicted, indicating the occurrence of complex trophic interactions. These results further complicate the understanding of these mixed culture microbial processes but also expand the expectation of compounds that could potentially be produced with this technology.

  2. Realizing stock market crashes: stochastic cusp catastrophe model of returns under time-varying volatility

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Kukačka, Jiří

    2015-01-01

    Roč. 15, č. 6 (2015), s. 959-973 ISSN 1469-7688 R&D Projects: GA ČR GA402/09/0965; GA ČR GA13-32263S EU Projects: European Commission 612955 - FINMAP Institutional support: RVO:67985556 Keywords : Stochastic cusp catastrophe model * Realized volatility * Bifurcations * Stock market crash Subject RIV: AH - Economics Impact factor: 0.794, year: 2015 http://library.utia.cas.cz/separaty/2014/E/barunik-0434202.pdf

  3. Modeling and forecasting exchange rate volatility in time-frequency domain

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Křehlík, Tomáš; Vácha, Lukáš

    2016-01-01

    Roč. 251, č. 1 (2016), s. 329-340 ISSN 0377-2217 R&D Projects: GA ČR GA13-32263S EU Projects: European Commission 612955 - FINMAP Institutional support: RVO:67985556 Keywords : Realized GARCH * Wavelet decomposition * Jumps * Multi-period-ahead volatility forecasting Subject RIV: AH - Economics Impact factor: 3.297, year: 2016 http://library.utia.cas.cz/separaty/2016/E/barunik-0456184.pdf

  4. Controlled production of Camembert-type cheeses. Part II. Changes in the concentration of the more volatile compounds.

    Science.gov (United States)

    Leclercq-Perlat, Marie-Noëlle; Latrille, Eric; Corrieu, Georges; Spinnler, Henry-Eric

    2004-08-01

    Flavour generation in cheese is a major aspect of ripening. In order to enhance aromatic qualities it is necessary to better understand the chemical and microbiological changes. Experimental Camembert-type cheeses were prepared in duplicate from pasteurized milk inoculated with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti and Brevibacterium linens under aseptic conditions. Two replicates performed under controlled conditions of temperature (12 degrees C), relative humidity (95 +/- 2%), and atmosphere showed similar ripening characteristics. The evolutions of metabolite concentrations were studied during ripening. The volatile components were extracted by dynamic headspace extraction, separated and quantified by gas chromatography and identified by mass spectrometry. For each cheese the volatile concentrations varied with the part considered (rind or core). Except for ethyl acetate and 2-pentanone, the volatile quantities observed were higher than their perception thresholds. The flavour component production was best correlated with the starter strains. During the first 10 days the ester formations (ethyl, butyl and isoamyl acetates) were associated with the concentrations of K. lactis and G. candidum. The rind quantity of esters was lower than that observed in core probably due to (1) a diffusion from the core to the surface and (2) evaporation from the surface to the chamber atmosphere. G. candidum and Brev. linens association produced 3 methyl butanol and methyl 3-butanal from leucine, respectively. DMDS came from the methionine catabolism due to Brev. linens. Styrene production was attributed to Pen. camemberti. 2-Pentanone evolution was associated with Pen. camemberti spores and G. candidum. 2-Heptanone changes were not directly related to flora activities while 2-octanone production was essentially due to G. candidum. This study also demonstrates the determining role of volatile component diffusion.

  5. Effect of total solids content on methane and volatile fatty acid production in anaerobic digestion of food waste.

    Science.gov (United States)

    Liotta, Flavia; d'Antonio, Giuseppe; Esposito, Giovanni; Fabbricino, Massimiliano; van Hullebusch, Eric D; Lens, Piet N L; Pirozzi, Francesco; Pontoni, Ludovico

    2014-10-01

    This work investigates the role of the moisture content on anaerobic digestion of food waste, as representative of rapidly biodegradable substrates, analysing the role of volatile fatty acid production on process kinetics. A range of total solids from 4.5% to 19.2% is considered in order to compare methane yields and kinetics of reactors operated under wet to dry conditions. The experimental results show a reduction of the specific final methane yield of 4.3% and 40.8% in semi-dry and dry conditions compared with wet conditions. A decreasing trend of the specific initial methane production rate is observed when increasing the total solids concentration. Because of lack of water, volatile fatty acids accumulation occurs during the first step of the process at semi-dry and dry conditions, which is considered to be responsible for the reduction of process kinetic rates. The total volatile fatty acids concentration and speciation are proposed as indicators of process development at different total solids content. © The Author(s) 2014.

  6. Study on the correlation between volatile fatty acids and gas production in dry fermentation of kitchen waste

    Science.gov (United States)

    Li, Qiangqiang; Ma, Yunfeng; Du, Boying; Wang, Qi; Hu, Qiongqiong; Bian, Yushan

    2018-02-01

    In this study, continuous kitchen waste fermentation and anaerobic digestion experiments were conducted to analyze the gas production potential, and to study the correlation between gas production rate and volatile fatty acid (VFAs) and its component concentration. During the experiment, the total solid(TS) concentration of the reaction system was increased by adding the kitchen waste, analysis of kitchen waste dry fermentation process to start, run, imbalance and imbalance after recovery and the parameters in the process of realizing the change trend and influencing factors of dry fermentation process, pH and ammonia concentration.

  7. Fungal volatile compounds induce production of the secondary metabolite Sodorifen in Serratia plymuthica PRI-2C

    NARCIS (Netherlands)

    Schmidt, R. (Ruth); V. de Jager (Victor); Zühlke, D. (Daniela); Wolff, C. (Christian); J. Bernhardt (Jörg); Cankar, K. (Katarina); Beekwilder, J. (Jules); W.F.J. van IJcken (Wilfred); F. Sleutels (Frank); De Boer, W. (Wietse); Riedel, K. (Katharina); Garbeva, P. (Paolina)

    2017-01-01

    textabstractThe ability of bacteria and fungi to communicate with each other is a remarkable aspect of the microbial world. It is recognized that volatile organic compounds (VOCs) act as communication signals, however the molecular responses by bacteria to fungal VOCs remain unknown. Here we perform

  8. Fungal volatile compounds induce production of the secondary metabolite Sodorifen in Serratia plymuthica PRI-2C

    NARCIS (Netherlands)

    Schmidt, R.L.; de Jager, V.C.L.; Zühlke, D.; Wolff, C.; Bernhardt, J.; Cankar, Katarina; Beekwilder, J.; van Ijcken, W.; Sleutels, Frank; De Boer, W.; Riedel, K.; Garbeva, P.V.

    2017-01-01

    The ability of bacteria and fungi to communicate with each other is a remarkable aspect of the microbial world. It is recognized that volatile organic compounds (VOCs) act as communication signals, however the molecular responses by bacteria to fungal VOCs remain unknown. Here we perform

  9. Development of volatile compounds during storage at various conditions of different lipid containing lip balm products

    DEFF Research Database (Denmark)

    Thomsen, Birgitte Raagaard; Horn, A. F.; Hyldig, Grethe

    for their development of volatile compounds by dynamic headspace gas chromatography-mass spectrometry and peroxide value, and compared to samples stored at 2°C in the dark. In addition, sensory analyses were carried out to assess the off-odours developed in the samples. The result showed that addition of iron increased...

  10. Volatile fatty acids production from sewage organic matter by combined bioflocculation and anaerobic fermentation

    NARCIS (Netherlands)

    Khiewwijit, R.; Keesman, K.J.; Rijnaarts, H.H.M.; Temmink, B.G.

    2014-01-01

    This work aims at exploring the feasibility of a combined process bioflocculation to concentrate sewage organic matter and anaerobic fermentation to produce volatile fatty acids (VFA). Bioflocculation, using a high-loaded aerobic membrane bioreactor (HL-MBR), was operated at an HRT of 1 h and an SRT

  11. Alcohol production through volatile fatty acids reduction with hydrogen as electron donor by mixed cultures

    NARCIS (Netherlands)

    Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2008-01-01

    In this research we demonstrated a new method to produce alcohols. It was experimentally feasible to produce ethanol, propanol and butanol from solely volatile fatty acids (VFAs) with hydrogen as electron donor. In batch tests, VFAs such as acetic, propionic and butyric acids were reduced by mixed

  12. Volatilities of ruthenium, iodine, and technetium on calcining fission product nitrate wastes

    International Nuclear Information System (INIS)

    Rimshaw, S.J.; Case, F.N.

    1980-01-01

    Various high-level nitrate wastes were subjected to formic acid denitration. Formic acid reacts with the nitrate anion to yield noncondensable, inert gases according to the following equation: 4 HCOOH + 2 HNO 3 → N 2 O + 4 CO 2 + 5 H 2 O. These gases can be scrubbed free of 106 Ru, 131 I, and 99 Tc radioactivities prior to elimination from the plant by passage through HEPA filters. The formation of deleterious NO/sub x/ is avoided. Moreover, formic acid reduces ruthenium to a lower valence state with a sharp reduction in RuO 4 volatility during subsequent calcination of the pretreated waste. It is shown that a minimum of 3% of RuO 4 in an off-gas stream reacts with Davison silica gel (Grade 40) to give a fine RuO 2 aerosol having a particle size of 0.5 μ. This RuO 2 aerosol passes through water or weak acid scrub solutions but is trapped by a caustic scrub solution. Iodine volatilizes almost completely on calcining an acidic waste, and the iodine volatility increases with increasing calcination temperature. On calcining an alkaline sodium nitrate waste the iodine volatility is about an order of magnitude lower, with a relatively low iodine volatility of 0.39% at a calcination temperature of 250 0 C and a moderate volatility of 9.5% at 600 0 C. Volatilities of 99 Tc were generally 0 C. Data are presented to indicate that 99 Tc concentrates in the alkaline sodium nitrate supernatant waste, with approx. 10 mg 99 Tc being associated with each curie of 137 Cs present in the waste. It is shown that lutidine (2,4 dimethyl-pyridine) extracts Tc(VII) quantitatively from alkaline supernatant wastes. The distribution coefficient (K/sub D/) for Tc(VII) going into the organic phase in the above system is 102 for a simulated West Valley waste and 191 for a simulated Savannah River Plant (SRP) waste

  13. In vitro effects of Melaleuca alternifolia essential oil on growth and production of volatile sulphur compounds by oral bacteria.

    Science.gov (United States)

    Graziano, Talita Signoreti; Calil, Caroline Morini; Sartoratto, Adilson; Franco, Gilson César Nobre; Groppo, Francisco Carlos; Cogo-Müller, Karina

    2016-01-01

    Halitosis can be caused by microorganisms that produce volatile sulphur compounds (VSCs), which colonize the surface of the tongue and subgingival sites. Studies have reported that the use of natural products can reduce the bacterial load and, consequently, the development of halitosis. The aim of this study was to evaluate the antimicrobial activity of the essential oil of Melaleuca alternifolia on the growth and volatile sulphur compound (VSC) production of oral bacteria compared with chlorhexidine. The effects of these substances were evaluated by the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in planktonic cultures of Porphyromonas gingivalis and Porphyromonas endodontalis. In addition, gas chromatography analyses were performed to measure the concentration of VSCs from bacterial cultures and to characterize M. alternifolia oil components. The MIC and MBC values were as follows: M. alternifolia - P. gingivalis (MIC and MBC=0.007%), P. endodontalis (MIC and MBC=0.007%=0.5%); chlorhexidine - P. gingivalis and P. endodontalis (MIC and MBC=1.5 mg/mL). M. alternifolia significantly reduced the growth and production of hydrogen sulfide (H2S) by P. gingivalis (pendodontalis (pendodontalis. For P. gingivalis, the production of H2S and CH3SH decreased (p<0.05, ANOVA-Dunnet). M. alternifolia can reduce bacterial growth and VSCs production and could be used as an alternative to chlorhexidine.

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

    Directory of Open Access Journals (Sweden)

    Mette Marie Løkke

    2012-11-01

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

  15. Effect of organic loading rate on methane and volatile fatty acids productions from anaerobic treatment of palm oil mill effluent in UASB and UFAF reactors

    Directory of Open Access Journals (Sweden)

    Sumate Chaiprapat

    2007-05-01

    Full Text Available Anaerobic treatment of palm oil mill effluent (POME with the separation of the acidogenic and methanogenic phase was studied in an up-flow anaerobic sludge blanket (UASB reactor and an up-flowanaerobic filter (UFAF reactor. Furthermore, the effect of OLR on methane and volatile fatty acid productions in UASB and UFAF reactors was investigated. In this research, UASB as acidogenic reactor wasused for volatile fatty acid production and UFAF as methanogenic reactor was used for methane production. Therefore, POME without pH adjustment was used as influent for the UASB reactor. Moreover, the syntheticwastewater with pH adjustment to 6.00 was fed into the UFAF reactor. The inoculum source for both reactors was the combination of POME sludge collected from the CSTR of a POME treatment plant and granulesludge collected from the UASB reactor of a frozen sea food industry treatment plant. During experimental operation, the organic loading rate (OLR was gradually increased from 2.50 to 17.5 g COD/l/day in theUASB reactor and 1.10 to 10.0 g COD/l/day in the UFAF reactor. Consequently, hydraulic retention time (HRT ranged from 20.0 to 2.90 days in the UASB reactor and from 13.5 to 1.50 days in the UFAF reactor.The result showed that the COD removal efficiency from both reactors was greater than 60.0%. In addition, the total volatile fatty acids increased with the increasing OLR. The total volatile fatty acids and acetic acidproduction in the UASB reactor reached 5.50 g/l and 4.90 g/l, respectively at OLR of 17.5 g COD/l/day and HRT of 2.90 days before washout was observed. In the UFAF reactor, the methane and biogas productionincreased with increasing OLR until an OLR of 7.50 g COD/l/day. However, the methane and biogas production significantly decreased when OLR increased up to 10.0 g COD/l/day. Therefore, the optimum OLR inthe laboratory-scale UASB and UFAF reactors were concluded to be 15.5 and 7.50 g COD/l/day, respectively.

  16. Effect of extraction time on antioxidants and bioactive volatile components of green tea (Camellia sinensis, using GC/MS

    Directory of Open Access Journals (Sweden)

    Mudasir Ahmad

    2015-12-01

    Full Text Available Two green tea types, leaf grade and sanding, were extracted at different time intervals: 20, 40, and 120 min at a constant temperature of 50°C. The extracts were analyzed by GC/MS technique. The major compounds identified were myristic acid, palmitic acid, stearic acid, oleic acid, 1H-purine-2,6-dione, caffeine, linoleic acid, diethyl ester, and 1H-purine-6-amine. Stearic acid, palmitic acid, linoleic acid, and myristic acid were more abundantly present in the leaf-grade variety than sanding. However, some levels of acetic acid, cyclobutanol, hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, and caffeine were also found in both the tea types. Most of the volatile compounds were detected between 20–40-min time of extraction. The 40-min time of extraction also showed the maximum content of polyphenols and antioxidants in both the tea types. Thus, 40 min was suggested as the most suitable time for maximum extraction of bioactive volatiles, antioxidants, and polyphenols from green tea.

  17. Approach of describing dynamic production of volatile fatty acids from sludge alkaline fermentation.

    Science.gov (United States)

    Wang, Dongbo; Liu, Yiwen; Ngo, Huu Hao; Zhang, Chang; Yang, Qi; Peng, Lai; He, Dandan; Zeng, Guangming; Li, Xiaoming; Ni, Bing-Jie

    2017-08-01

    In this work, a mathematical model was developed to describe the dynamics of fermentation products in sludge alkaline fermentation systems for the first time. In this model, the impacts of alkaline fermentation on sludge disintegration, hydrolysis, acidogenesis, acetogenesis, and methanogenesis processes are specifically considered for describing the high-level formation of fermentation products. The model proposed successfully reproduced the experimental data obtained from five independent sludge alkaline fermentation studies. The modeling results showed that alkaline fermentation largely facilitated the disintegration, acidogenesis, and acetogenesis processes and severely inhibited methanogenesis process. With the pH increase from 7.0 to 10.0, the disintegration, acidogenesis, and acetogenesis processes respectively increased by 53%, 1030%, and 30% while methane production decreased by 3800%. However, no substantial effect on hydrolysis process was found. The model also indicated that the pathway of acetoclastic methanogenesis was more severely inhibited by alkaline condition than that of hydrogentrophic methanogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Effect of gamma radiation and storage time on the volatile constituents, pirerine, piperettine and sensory quality of pepper

    Energy Technology Data Exchange (ETDEWEB)

    Bahari, I; Ishak, S; Ayub, M K [National Univ. of Malaysia, Bangi, Selangor

    1983-12-01

    The use of gamma radiation in prolonging the storage life of black and white peppers is promising. Doses up to 9 kGy and storage period up to 6 months did not significantly change (P<0.05) the volatile constituents of the peppers. Besides the increase in piperine content of unirradiated pepper there was no change in piperettine and piperine contents of both pepper with respect to increase in dose and storage time. No sensory change was detected for the treatments used (author).

  19. The effect of gamma radiation and storage time on the volatile constituents, pirerine, piperettine and sensory quality of pepper

    International Nuclear Information System (INIS)

    Bahari, I.; Ishak, S.; Ayub, M.K.

    1983-01-01

    The use of gamma radiation in prolonging the storage life of black and white peppers is promising. Doses up to 9 kGy and storage period up to 6 months did not significantly change (P<0.05) the volatile constituents of the peppers. Besides the increase in piperine content of unirradiated pepper there was no change in piperettine and piperine contents of both pepper with respect to increase in dose and storage time. No sensory change was detected for the treatments used (author)

  20. 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.

  1. Impact of yeast starter formulations on the production of volatile compounds during wine fermentation.

    Science.gov (United States)

    Romano, Patrizia; Pietrafesa, Rocchina; Romaniello, Rossana; Zambuto, Marianna; Calabretti, Antonella; Capece, Angela

    2015-01-01

    The most diffused starter formulation in winemaking is actually represented by active dry yeast (ADY). Spray-drying has been reported as an appropriate preservation method for yeast and other micro-organisms. Despite the numerous advantages of this method, the high air temperatures used can negatively affect cell viability and the fermentative performance of dried cells. In the present study, 11 wine S. cerevisiae strains (both indigenous and commercial) were submitted to spray-drying; different process conditions were tested in order to select the conditions allowing the highest strain survival. The strains exhibited high variability for tolerance to spray-drying treatment. Selected strains were tested in fermentation at laboratory scale in different formulations (free fresh cells, free dried cells, immobilized fresh cells and immobilized dried cells), in order to assess the influence of starter formulation on fermentative fitness of strains and aromatic quality of wine. The analysis of volatile fraction in the experimental wines produced by selected strains in different formulations allowed identification of > 50 aromatic compounds (alcohols, esters, ketones, aldehydes and terpenes). The results obtained showed that the starter formulation significantly influenced the content of volatile compounds. In particular, the wines obtained by strains in dried forms (as both free and immobilized cells) contained higher numbers of volatile compounds than wines obtained from fresh cells. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Pineapple (Ananas comosus L. Merr.) wine production in Angola: Characterisation of volatile aroma compounds and yeast native flora.

    Science.gov (United States)

    Dellacassa, Eduardo; Trenchs, Oriol; Fariña, Laura; Debernardis, Florencia; Perez, Gabriel; Boido, Eduardo; Carrau, Francisco

    2017-01-16

    A pineapple vinification process was conducted through inoculated and spontaneous fermentation to develop a process suitable for a quality beverage during two successive vintages in Huambo, Angola. Wines obtained with the conventional Saccharomyces cerevisiae strain, were analysed by gas chromatography, and a total of 61 volatile constituents were detected in the volatile fraction and 18 as glycosidically bound aroma compounds. Concentration levels of carbonyl and sulphur compounds were in agreement with the limited information reported about pineapple fruits of other regions. We report, for the first time in pineapple wines, the presence of significant concentrations of lactones, ketones, terpenes, norisoprenoids and a variety of volatile phenols. Eight native yeast strains were isolated from spontaneous batches. Further single-strain fermentations allowed us to characterise their suitability for commercial fermentation. Three native strains (Hanseniaspora opuntiae, H. uvarum and Meyerozyma guilliermondii) were selected with sensory potential to ferment pineapple fruits with increased flavour diversity. Results obtained here contribute to a better understanding of quality fermentation alternatives of this tropical fruit in subtropical regions. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Associations between the sensory attributes and volatile composition of Cabernet Sauvignon wines and the volatile composition of the grapes used for their production.

    Science.gov (United States)

    Forde, Ciarán G; Cox, Agnieszka; Williams, Emlyn R; Boss, Paul K

    2011-03-23

    The sensory properties of wine are influenced by the chemical composition of the grapes used to produce them. Identification of grape and wine chemical markers associated with the attributes perceived by the consumer of the wine will enable better prediction of the potential of a parcel of grapes to produce wine of a certain flavor. This study explores the relationships between Cabernet Sauvignon grape volatile composition and wine volatile profiles with the sensory properties of wines. Twenty grape samples were obtained from nine vineyard sites across three vintages and wines vinified from these parcels using controlled winemaking methods. The volatile composition of the grapes were analyzed by SBSE-GCMS, the wines were analyzed by SPME-GCMS, and these data sets were compared to that obtained from the sensory analysis of the wines. Statistical treatment of the data to account for vintage and region effects allowed underlying relationships to be seen between wine sensory attributes and wine or grape volatile components. The observed associations between grape or wine volatile compounds and wine sensory attributes has revealed target compounds and pathways whose levels may reflect the biochemical effects on grape composition by differing growth conditions during berry development and ripening. The compounds identified in this study may be useful grape or wine markers for potential wine sensory characteristics.

  4. Effect of initial total solids concentration on volatile fatty acid production from food waste during anaerobic acidification.

    Science.gov (United States)

    Wang, Quan; Jiang, Jianguo; Zhang, Yujing; Li, Kaimin

    2015-01-01

    The effect of initial total solids (TS) concentration on volatile fatty acid (VFAs) production from food waste under mesophilic conditions (35 °C) was determined. VFAs concentration and composition, biogas production, soluble chemical oxygen demand concentration, TS and volatile solids (VS) reduction, and ammonia nitrogen [Formula: see text] release were investigated. The VFAs concentrations were 26.10, 39.68, 59.58, and 62.64 g COD/L at TS contents of 40, 70, 100, and 130 g/L, respectively. While the VFAs' yields ranged from 0.467 to 0.799 g COD/g VSfed, decreased as initial TS increased. The percentage of propionate was not affected by TS concentration, accounting for 30.19-34.86% of the total VFAs, while a higher percentage of butyrate and lower percentage of acetate was achieved at a higher TS concentration. Biogas included mainly hydrogen and carbon dioxide and the maximum hydrogen yield of 148.9 ml/g VSfed was obtained at 130 g TS/L. [Formula: see text] concentration, TS and VS reductions increased as initial TS increased. Considering the above variables, we conclude that initial TS of 100 g/L shall be the most appropriate to VFAs production.

  5. Energetics of gaseous and volatile fission products in molten U–10Zr alloy: A density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ning; Tian, Jie; Jiang, Tao; Yang, Yanqiu; Hu, Sheng [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Peng, Shuming, E-mail: pengshuming@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Yan, Liuming [Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

    2015-11-15

    Gaseous and volatile fission products have a number of adverse effects on the safety and efficiency of the U–10Zr alloy fuel. The theoretical calculations were applied to investigate the energetics related to the formation, nucleation, and degassing of gaseous and volatile fission products (Kr, Xe and I) in molten U–10Zr alloy. The molecular dynamics (MD) simulations were applied to generate equilibrium configurations. The density functional theory (DFT) calculations were used to build atomistic models including molten U–10Zr alloy as well as its fission products substituted systems. The vacancy formation in liquid U–10Zr alloy were studied using DFT calculations, with average Gibbs free formation energies at 8.266 and 6.333 eV for U- and Zr-vacancies, respectively. And the interaction energies were −1.911 eV, −2.390 eV, and −1.826 eV for the I–I, Xe–Xe, and Kr–Kr interaction in lattice when two of the adjacent uranium atoms were substituted by gaseous atoms. So it could be concluded that the interaction between I, Kr, and Xe in lattice is powerful than the interaction between these two atoms and the other lattice atoms in U–10Zr.

  6. Bioelectrochemical reduction of volatile fatty acids in anaerobic digestion effluent for the production of biofuels.

    Science.gov (United States)

    Kondaveeti, Sanath; Min, Booki

    2015-12-15

    This study proves for the first time the feasibility of biofuel production from anaerobic digestion effluent via bioelectrochemical cell operation at various applied cell voltages (1.0, 1.5 and 2.0 V). An increase in cell voltage from 1 to 2 V resulted in more reduction current generation (-0.48 to -0.78 mA) at a lowered cathode potential (-0.45 to -0.84 mV vs Ag/AgCl). Various alcohols were produced depending on applied cell voltages, and the main products were butanol, ethanol, and propanol. Hydrogen and methane production were also observed in the headspace of the cell. A large amount of lactic acid was unexpectedly formed at all conditions, which might be the primary cause of the limited biofuel production. The addition of neutral red (NR) to the system could increase the cathodic reduction current, and thus more biofuels were produced with an enhanced alcohol formation compared to without a mediator. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Volatile composition and enantioselective analysis of chiral terpenoids of nine fruit and vegetable fibres resulting from juice industry by-products

    OpenAIRE

    Marsol i Vall, Alexis; Sgorbini, Barbara; Cagliero, Cecilia; Bicchi, Carlo; Eras i Joli, Jordi; Balcells Fluvià, Mercè

    2017-01-01

    Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging...

  8. In vitro effects of Melaleuca alternifolia essential oil on growth and production of volatile sulphur compounds by oral bacteria

    Directory of Open Access Journals (Sweden)

    Talita Signoreti GRAZIANO

    Full Text Available ABSTRACT Objective Halitosis can be caused by microorganisms that produce volatile sulphur compounds (VSCs, which colonize the surface of the tongue and subgingival sites. Studies have reported that the use of natural products can reduce the bacterial load and, consequently, the development of halitosis. The aim of this study was to evaluate the antimicrobial activity of the essential oil of Melaleuca alternifolia on the growth and volatile sulphur compound (VSC production of oral bacteria compared with chlorhexidine. Material and Methods The effects of these substances were evaluated by the Minimum Inhibitory Concentration (MIC and Minimum Bactericidal Concentration (MBC in planktonic cultures of Porphyromonas gingivalis and Porphyromonas endodontalis. In addition, gas chromatography analyses were performed to measure the concentration of VSCs from bacterial cultures and to characterize M. alternifolia oil components. Results The MIC and MBC values were as follows: M. alternifolia - P. gingivalis (MIC and MBC=0.007%, P. endodontalis (MIC and MBC=0.007%=0.5%; chlorhexidine - P. gingivalis and P. endodontalis (MIC and MBC=1.5 mg/mL. M. alternifolia significantly reduced the growth and production of hydrogen sulfide (H2S by P. gingivalis (p<0.05, ANOVA-Dunnet and the H2S and methyl mercaptan (CH3SH levels of P. endodontalis (p<0.05, ANOVA-Dunnet. Chlorhexidine reduced the growth of both microorganisms without altering the production of VSC in P. endodontalis. For P. gingivalis, the production of H2S and CH3SH decreased (p<0.05, ANOVA-Dunnet. Conclusion M. alternifolia can reduce bacterial growth and VSCs production and could be used as an alternative to chlorhexidine.

  9. Development of volatile compounds during storage of different skin care products at various conditions

    DEFF Research Database (Denmark)

    Horn, A. F.; Thomsen, Birgitte Raagaard; Hyldig, Grethe

    a storage experiment on three cleansing milks stored between 14 and 84 days, under different conditions. The samples were exposed to heat (20°C, 40°C and 50°C), light (samples at 20°C) and iron (samples at 40°C). Samples were analysed for their development of volatile compounds by dynamic headspace gas...... chromatography-mass spectrometry and peroxide value, and compared to samples stored at 2°C in the dark. In addition, sensory analyses were carried out to assess the off-odours developed in the samples....

  10. Variation in highbush blueberry floral volatile profiles as a function of pollination status, cultivar, time of day and flower part: implications for flower visitation by bees

    Science.gov (United States)

    Rodriguez-Saona, Cesar; Parra, Leonardo; Quiroz, Andrés; Isaacs, Rufus

    2011-01-01

    Background and Aims Studies of the effects of pollination on floral scent and bee visitation remain rare, particularly in agricultural crops. To fill this gap, the hypothesis that bee visitation to flowers decreases after pollination through reduced floral volatile emissions in highbush blueberries, Vaccinium corymbosum, was tested. Other sources of variation in floral emissions and the role of floral volatiles in bee attraction were also examined. Methods Pollinator visitation to blueberry flowers was manipulated by bagging all flowers within a bush (pollinator excluded) or leaving them unbagged (open pollinated), and then the effect on floral volatile emissions and future bee visitation were measured. Floral volatiles were also measured from different blueberry cultivars, times of the day and flower parts, and a study was conducted to test the attraction of bees to floral volatiles. Key Results Open-pollinated blueberry flowers had 32 % lower volatile emissions than pollinator-excluded flowers. In particular, cinnamyl alcohol, a major component of the floral blend that is emitted exclusively from petals, was emitted in lower quantities from open-pollinated flowers. Although, no differences in cinnamyl alcohol emissions were detected among three blueberry cultivars or at different times of day, some components of the blueberry floral blend were emitted in higher amounts from certain cultivars and at mid-day. Field observations showed that more bees visited bushes with pollinator-excluded flowers. Also, more honey bees were caught in traps baited with a synthetic blueberry floral blend than in unbaited traps. Conclusions Greater volatile emissions may help guide bees to unpollinated flowers, and thus increase plant fitness and bee energetic return when foraging in blueberries. Furthermore, the variation in volatile emissions from blueberry flowers depending on pollination status, plant cultivar and time of day suggests an adaptive role of floral signals in

  11. Variation in highbush blueberry floral volatile profiles as a function of pollination status, cultivar, time of day and flower part: implications for flower visitation by bees.

    Science.gov (United States)

    Rodriguez-Saona, Cesar; Parra, Leonardo; Quiroz, Andrés; Isaacs, Rufus

    2011-06-01

    Studies of the effects of pollination on floral scent and bee visitation remain rare, particularly in agricultural crops. To fill this gap, the hypothesis that bee visitation to flowers decreases after pollination through reduced floral volatile emissions in highbush blueberries, Vaccinium corymbosum, was tested. Other sources of variation in floral emissions and the role of floral volatiles in bee attraction were also examined. Pollinator visitation to blueberry flowers was manipulated by bagging all flowers within a bush (pollinator excluded) or leaving them unbagged (open pollinated), and then the effect on floral volatile emissions and future bee visitation were measured. Floral volatiles were also measured from different blueberry cultivars, times of the day and flower parts, and a study was conducted to test the attraction of bees to floral volatiles. Open-pollinated blueberry flowers had 32 % lower volatile emissions than pollinator-excluded flowers. In particular, cinnamyl alcohol, a major component of the floral blend that is emitted exclusively from petals, was emitted in lower quantities from open-pollinated flowers. Although, no differences in cinnamyl alcohol emissions were detected among three blueberry cultivars or at different times of day, some components of the blueberry floral blend were emitted in higher amounts from certain cultivars and at mid-day. Field observations showed that more bees visited bushes with pollinator-excluded flowers. Also, more honey bees were caught in traps baited with a synthetic blueberry floral blend than in unbaited traps. Greater volatile emissions may help guide bees to unpollinated flowers, and thus increase plant fitness and bee energetic return when foraging in blueberries. Furthermore, the variation in volatile emissions from blueberry flowers depending on pollination status, plant cultivar and time of day suggests an adaptive role of floral signals in increasing pollination of flowers.

  12. Strategies to keep your business operating through times of price volatility

    International Nuclear Information System (INIS)

    Spearman, C.

    2002-01-01

    The past (the promises), the present (the reality), and the future (the dream) of electricity deregulation in Alberta are reviewed. According to this outspoken critic of the system the promise was orderly transition, the introduction of industry structure and regulatory reforms that would preserve the 'Alberta advantage' of competitive electricity prices. The reality is government indecision, price volatility, uncertainty and complexity, resulting in poor understanding of the system on the part of consumers, hence bad decisions, rapidly declining confidence, high prices, and eroded competitiveness. In short, costs have skyrocketed and benefits are nowhere to be seen. As far as the dream is concerned the picture is cloudy, based on the following factors: load settlement is still in a mess, transmission remains a major issue, market power of former monopolies is still a concern, and future supply is uncertain in the absence of additional capacity. What is needed to make good on the original promises is a clear vision, stability, a cohesive plan, leadership, decisiveness, certainty and simplicity

  13. Influence of environmental conditions on production of volatiles by Trichoderma atroviride in relation with the sick building syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Polizzi, Viviana [Ghent University, Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Coupure links 653, B-9000 Ghent (Belgium); Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Food Analysis, Harelbekestraat 72, B-9000 Ghent (Belgium); Adams, An; De Kimpe, Norbert [Ghent University, Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Coupure links 653, B-9000 Ghent (Belgium); Picco, Anna Maria [Pavia University, Faculty of Sciences, Department of Territorial Ecology and Environment, via S. Epifanio 14, 27100 Pavia (Italy); Adriaens, Els; Lenoir, Joke [Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutical Technology, Harelbekestraat 72, B-9000 Ghent (Belgium); Van Peteghem, Carlos; De Saeger, Sarah [Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Food Analysis, Harelbekestraat 72, B-9000 Ghent (Belgium)

    2011-04-15

    A Trichoderma atroviride strain was isolated from a water-damaged office and the production of microbial volatile organic compounds (MVOCs) was investigated by means of headspace solid phase microextraction GC-MS. Different growth conditions (substrate, temperature, relative humidity) were selected, resembling indoor parameters, to elucidate a possible relationship between MVOCs, produced by Trichoderma atroviride, and the Sick Building Syndrome. In general, the range of MVOCs and the emitted quantities were larger on malt extract agar (MEA) than on wallpaper and plasterboard. Particular attention was dedicated to the volatile marker 6-pentyl-2-pyrone, a compound produced in high quantities on MEA, and its mucosal irritation potency was shown in a slug mucosal irritation assay. Some compounds characteristic for growth on specific building materials were detected, e.g. 2-ethylcyclopentanone, menthone, iso-menthone and trans-p-menth-2-en-7-ol on plasterboard and 4-heptanone and 1-octen-3-ol on wallpaper. Relative humidity and substrate had a more important effect on MVOC production than temperature. (author)

  14. 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....

  15. Time management strategies for research productivity.

    Science.gov (United States)

    Chase, Jo-Ana D; Topp, Robert; Smith, Carol E; Cohen, Marlene Z; Fahrenwald, Nancy; Zerwic, Julie J; Benefield, Lazelle E; Anderson, Cindy M; Conn, Vicki S

    2013-02-01

    Researchers function in a complex environment and carry multiple role responsibilities. This environment is prone to various distractions that can derail productivity and decrease efficiency. Effective time management allows researchers to maintain focus on their work, contributing to research productivity. Thus, improving time management skills is essential to developing and sustaining a successful program of research. This article presents time management strategies addressing behaviors surrounding time assessment, planning, and monitoring. Herein, the Western Journal of Nursing Research editorial board recommends strategies to enhance time management, including setting realistic goals, prioritizing, and optimizing planning. Involving a team, problem-solving barriers, and early management of potential distractions can facilitate maintaining focus on a research program. Continually evaluating the effectiveness of time management strategies allows researchers to identify areas of improvement and recognize progress.

  16. Enhanced volatile fatty acids production from anaerobic fermentation of food waste: A mini-review focusing on acidogenic metabolic pathways.

    Science.gov (United States)

    Zhou, Miaomiao; Yan, Binghua; Wong, Jonathan W C; Zhang, Yang

    2018-01-01

    Recently, efficient disposal of food waste (FW) with potential resource recovery has attracted great attentions. Due to its easily biodegradable nature, rich nutrient availability and high moisture content, FW is regarded as favorable substrate for anaerobic digestion (AD). Both waste disposal and energy recovery can be fulfilled during AD of FW. Volatile fatty acids (VFAs) which are the products of the first-two stages of AD, are widely applied in chemical industry as platform chemicals recently. Concentration and distribution of VFAs is the result of acidogenic metabolic pathways, which can be affected by the micro-environment (e.g. pH) in the digester. Hence, the clear elucidation of the acidogenic metabolic pathways is essential for optimization of acidogenic process for efficient product recovery. This review summarizes major acidogenic metabolic pathways and regulating strategies for enhancing VFAs recovery during acidogenic fermentation of FW. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. ANTIFUNGAL ACTIVITY OF VOLATILE COMPONENTS GENERATED BY ESSENTIAL OILS AGAINST THE GENUS PENICILLIUM ISOLATED FROM BAKERY PRODUCTS

    Directory of Open Access Journals (Sweden)

    Miroslava Císarová

    2015-02-01

    Full Text Available The aim of this study was evaluation of the antifungal activity of 5 essential oils (EOs. We concretely used thyme, clove, basil, jasmine and rosemary EOs by vapor contact against the fungal species, namely Penicillium citrinum, P. chrysogenum, P. hordei, P. citreonigrum, and P. viridicatum and their ability to affect production of mycotoxins. Each fungus was inoculated in the centre on Czapek Yeast Autolysate Agar (CYA dishes. Dishes were tightly sealed with parafilm and incubated for fourteen days at 25 ± 1 °C (three replicates were used for each treatment. Volatile phase effect of 50 μl of the essential oils was found to inhibit on growth of Penicillium spp.. Complete growth inhibition of the isolates by EOs of thyme and clove was observed. The EO of basil had antifungal effect on growth of P. citreonigrum only after 3rd and 7th day of the incubation at concentration 100 % of EO, like a P. viridicatum, which was inhibited by basil EO (100 % in comparison with control sets. Data was evaluated statistically by 95.0 % Tukey HSD test. In this study we also tested potentional effect of EOs to affect production of mycotoxins of tested Penicillium isolates which are potential toxigenic fungi. After 14 days of incubation with EOs (100 % with control sets, they were screened for a production of mycotoxins by TLC chromatography. Results showed non affecting production of mycotoxins by tested EOs. Conclusions indicate that volatile phase of combinations of thyme oil and clove oil showed good potential in the inhibition of growth of Penicillium spp. EOs should find a practical application in the inhibition of the fungal mycelial growth in some kind of the food.

  18. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    Directory of Open Access Journals (Sweden)

    Maaike evan Agtmaal

    2015-07-01

    Full Text Available There is increasing evidence that microbial volatiles (VOCs play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial community composition would affect the production by soils of VOCs suppressing the plant-pathogenic oomycete Pythium. Using pyrosequencing of 16S ribosomal gene fragments we compared the composition of bacterial communities in sandy soils that had been exposed to anaerobic disinfestation (AD, a treatment used to kill harmful soil organisms, with the composition in untreated soils. Three months after the AD treatment had been finished, there was still a clear legacy effect of the former anaerobic stress on bacterial community composition with a strong increase in relative abundance of the phylum Bacteroidetes and a significant decrease of the phyla Acidobacteria, Planctomycetes, Nitrospirae, Chloroflexi and Chlorobi. This change in bacterial community composition coincided with loss of production of Pythium suppressing soil volatiles (VOCs and of suppression of Pythium impacts on Hyacinth root development. One year later, the composition of the bacterial community in the AD soils was reflecting that of the untreated soils. In addition, both production of Pythium-suppressing VOCs and suppression of Pythium in Hyacinth bioassays had returned to the levels of the untreated soil. GC/MS analysis identified several VOCs, among which compounds known to be antifungal, that were produced in the untreated soils but not in the AD soils. These compounds were again produced 15 months after the AD treatment. Our data indicate that soils exposed to a drastic stress can temporarily lose pathogen suppressive characteristics and that both loss and return of these suppressive characteristics coincides with shifts in the soil bacterial community composition. Our data are

  19. Studies on the possibilities of using a by-product resulting during the extraction of the volatile oils from conifer twigs and needles in the leather industry

    Energy Technology Data Exchange (ETDEWEB)

    Chirita, A.; Toma, A.R.; Cocis, V.

    1979-01-01

    Organic by-products containing 19-40% tannin from the water extraction of volatile oils from spruce bark, twigs, and needles were useful when mixed in a 1:1 ratio with BCF synthetic tannin auxiliary to tan hide, and similar by-products containing 16-31% reducing substances could be used to replace glucose as reducing agent in chrome tanning.

  20. 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.

  1. Optimization of volatile fatty acid production with co-substrate of food wastes and dewatered excess sludge using response surface methodology.

    Science.gov (United States)

    Hong, Chen; Haiyun, Wu

    2010-07-01

    Central-composite design (CCD) and response surface methodology (RSM) were used to optimize the parameters of volatile fatty acid (VFA) production from food wastes and dewatered excess sludge in a semi-continuous process. The effects of four variables (food wastes composition in the co-substrate of food wastes and excess sludge, hydraulic retention time (HRT), organic loading rate (OLR), and pH) on acidogenesis were evaluated individually and interactively. The optimum condition derived via RSM was food wastes composition, 88.03%; HRT, 8.92 days; OLR, 8.31 g VSS/ld; and pH 6.99. The experimental VFA concentration was 29,099 mg/l under this optimum condition, which was well in agreement with the predicted value of 28,000 mg/l. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  2. Worker's perceptions of time, time-use-attitudes and productivity

    Directory of Open Access Journals (Sweden)

    E. Ben-Baruch

    1991-06-01

    Full Text Available Decreasing productivity and increasing wage demands are singled out as being crucial problems facing the economy of South Africa. Changes in the time perceptions and time-use-attitudes of workers could play a decisive role in increasing productivity. The relationships between time perception, needs, motivation and productivity are analysed. Culture, tradition, economy, and environment lend a specific significance to these variables. Workers in a technological society should be guided to adapt to and live by the value system needed to uphold productivity. Opsomming Voortdurende afnemende produktiwiteit teenoor looneise wat styg, is een van die kritieke probleme waarmee die Suid-Afrikaanse ekonomie gekonfronteer word. Die verandering van werkers se tydpersepsie en verandering van houdinge teenoor die benutting van tyd kan deurslaggewend in die verhoging van produktiwiteit wees. In die lig hiervan is die verwantskap tussen tydpersepsie, behoeftes, motivering en prodrktiwiteit ondersoek. In die ontleding word aandag geskenk aan die invloed wat kultuur, tradisie, ekonomie en die omgewing op hierdie veranderlikes het. Opieiding in 'n tegnologiese samelewmg behoort daarop gerig te wees om 'n waardesisteem by werkers te laat ontwikkel wat produktiwiteit kan bevorder.

  3. Time-resolved analysis of primary volatile emissions and secondary aerosol formation potential from a small-scale pellet boiler

    Science.gov (United States)

    Czech, Hendryk; Pieber, Simone M.; Tiitta, Petri; Sippula, Olli; Kortelainen, Miika; Lamberg, Heikki; Grigonyte, Julija; Streibel, Thorsten; Prévôt, André S. H.; Jokiniemi, Jorma; Zimmermann, Ralf

    2017-06-01

    Small-scale pellet boilers and stoves became popular as a wood combustion appliance for domestic heating in Europe, North America and Asia due to economic and environmental aspects. Therefore, an increasing contribution of pellet boilers to air pollution is expected despite their general high combustion efficiency. As emissions of primary organic aerosol (POA) and permanent gases of pellet boilers are well investigated, the scope of this study was to investigate the volatile organic emissions and the formation potential of secondary aerosols for this type of appliance. Fresh and aged emissions were analysed by a soot-particle aerosol time-of-flight mass spectrometry (SP-AMS) and the molecular composition of the volatile precursors with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) at different pellet boiler operation conditions. Organic emissions in the gas phase were dominated by unsaturated hydrocarbons while wood-specific VOCs, e.g. phenolic species or substituted furans, were only detected during the starting phase. Furthermore, organic emissions in the gas phase were found to correlate with fuel grade and combustion technology in terms of secondary air supply. Secondary organic aerosols of optimised pellet boiler conditions (OPT, state-of-the-art combustion appliance) and reduced secondary air supply (RSA, used as a proxy for pellet boilers of older type) were studied by simulating atmospheric ageing in a Potential Aerosol Mass (PAM) flow reactor. Different increases in OA mass (55% for OPT, 102% for RSA), associated with higher average carbon oxidation state and O:C, could be observed in a PAM chamber experiment. Finally, it was found that derived SOA yields and emission factors were distinctly lower than reported for log wood stoves.

  4. Time-ordered products and Schwinger functions

    International Nuclear Information System (INIS)

    Eckmann, J.P.; Epstein, H.

    1979-01-01

    It is shown that every system of time-ordered products for a local field theory determines a related system of Schwinger functions possessing an extended form of Osterwalder-Schrader positivity and that the converse is true provided certain growth conditions are satisfied. This is applied to the phi 3 4 theory and it is shown that the time-ordered functions and S-matrix elements admit the standard perturbation series as asymptotic expansions. (orig.) [de

  5. 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

  6. 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....

  7. “Gold” Pressed Essential Oil: An Essay on the Volatile Fragment from Citrus Juice Industry By-Products Chemistry and Bioactivity

    Directory of Open Access Journals (Sweden)

    V. N. Kapsaski-Kanelli

    2017-01-01

    Full Text Available Present essay explores the potentials of Citrus juice industry’s by-products as alternative bioactive natural products resources. Four crude Cold Pressed Essential Oils (CPEOs, derived from orange, lemon, grapefruit, and mandarin, were studied. All CPEOs were subjected to water distillation, in order to obtain the volatile fragment, which was further fractionated with respect to distillation period in two parts, concluding to eight samples. These samples along with the four original CPEOs were assessed in relation to their phytochemical content and their repellent and larvicidal properties against Asian Tiger Mosquito. The volatiles recovery rates ranged from 74% to 88% of the CPEO. Limonene presented a significant increase in all samples ranging from 8% to 52% of the respective CPEO’s content and peaked in mandarin’s 2nd volatile fragment which comprised 97% of the essential oil. The refinement process presented clear impacts on both bioassays: a significant increase in larvicidal potency was observed, annotated best by the improvement by 1100% and 1300% of the grapefruit volatile fractions; repellence testing provided only one significant result, the decrease of landings by 50% as a response to mandarin’s second volatile fraction. The applied methodology thus may be considered for the improvement of Citrus juice industry’s by-products chemistry and bioactivity.

  8. Volatile organic compound emissions during hot-pressing of southern pine particleboard : panel size effects and trade-off between press time and temperature

    Science.gov (United States)

    Wenlong Wang; Douglas J. Gardner; Melissa G.D. Baumann

    2002-01-01

    In previous research, it was shown that decreasing either press temperature or press time generally resulted in decreased volatile organic compound (VOC) emissions during the hot-pressing of southern pine particleboard. However, because it is impossible to reduce both pressing time and temperature while maintaining panel physical and mechanical properties, this study...

  9. The influences of delay time on the stability of a market model with stochastic volatility

    Science.gov (United States)

    Li, Jiang-Cheng; Mei, Dong-Cheng

    2013-02-01

    The effects of the delay time on the stability of a market model are investigated, by using a modified Heston model with a cubic nonlinearity and cross-correlated noise sources. These results indicate that: (i) There is an optimal delay time τo which maximally enhances the stability of the stock price under strong demand elasticity of stock price, and maximally reduces the stability of the stock price under weak demand elasticity of stock price; (ii) The cross correlation coefficient of noises and the delay time play an opposite role on the stability for the case of the delay time τo. Moreover, the probability density function of the escape time of stock price returns, the probability density function of the returns and the correlation function of the returns are compared with other literatures.

  10. Comparison of Three Methods for Extraction of Volatile Lipid Oxidation Products from Food Matrices for GC–MS Analysis

    DEFF Research Database (Denmark)

    Thomsen, Birgitte Raagaard; Yesiltas, Betül; Sørensen, Ann-Dorit Moltke

    2016-01-01

    The aim of this study was to compare three different collection methods; purge and trap, solid phase micro extraction and automated dynamic headspace/thermal desorption, all followed by GC–MS analysis used for the measurements of concentrations of volatile oxidation products in three different food...... of the calibration curves depending on the collection method. However, some challenges were observed for solid phase micro extraction and automated dynamic headspace/thermal desorption, namely, competition problems and overestimation of concentration by calibration curves, respectively. Based on the results, we...... suggest mainly to apply solid phase micro extraction on simple matrices and to be cautious with more complex matrices such as enriched milk and highly oxidized oils. Thereby, the study confirmed some challenges observed by other authors regarding competition problems on the fiber when using solid phase...

  11. Occupational health risk assessment of volatile organic compounds emitted from the coke production unit of a steel plant.

    Science.gov (United States)

    Dehghani, Fateme; Omidi, Fariborz; Heravizadeh, Omidreza; Barati Chamgordani, Saied; Gharibi, Vahid; Sotoudeh Manesh, Akbar

    2018-03-27

    In this study, cancer and non-cancer risks of exposure to volatile organic compounds in the coke production unit of a steel plant were evaluated. To determine individual exposure to benzene, toluene, xylene and ethylbenzene, personal samples were taken from the breathing zone of workers according to National Institute for Occupational Safety and Health (NIOSH) method 1501. Cancer and non-cancer risk assessment was performed, using US Environmental Protection Agency (US EPA) methods. Samples analysis showed that the concentration of benzene in the energy and biochemistry and the benzol refinement sections was higher than occupational exposure limits. The cancer risk for benzene in all sections was significantly higher than allowable limit; the non-cancer risk for benzene in all sections and toluene in the benzol refinement section was also higher than 1.0. In conclusion, the current control measures are not sufficient and should be improved for efficient control of occupational exposures.

  12. Assessment of control strategies for reducing volatile organic compound emissions from the polyvinyl chloride wallpaper production industry in Taiwan.

    Science.gov (United States)

    Chang, Chang-Tang; Chiou, Chyow-Shan

    2006-05-01

    This study attempts to assess the effectiveness of control strategies for reducing volatile organic compound (VOC) emission from the polyvinyl chloride (PVC) wallpaper production industry. In Taiwan, methyl ethyl ketone, TOL, and cyclohexanone have comprised the major content of solvents, accounting for approximately 113,000 t/yr to avoid excessive viscosity of plasticizer dioctyl phthalate (DOP) and to increase facility in working. Emissions of these VOCs from solvents have caused serious odor and worse air quality problems. In this study, 80 stacks in five factories were tested to evaluate emission characteristics at each VOC source. After examining the VOC concentrations in the flue gases and contents, the VOC emission rate before treatment and from fugitive sources was 93,000 and 800 t/yr, respectively. In this study, the semiwet electrostatic precipitator is recommended for use as cost-effective control equipment.

  13. Volatile and sensory profiling of Shiraz wine in response to alcohol management: comparison of harvest timing versus technological approaches.

    Science.gov (United States)

    Longo, Rocco; Blackman, John W; Antalick, Guillaume; Torley, Peter J; Rogiers, Suzy Y; Schmidtke, Leigh M

    2018-07-01

    The aim of this study was to compare the volatile and sensory profiles of Australian Shiraz red wines produced by several methods to achieve alcohol concentrations of 10.5 and 13.5% v/v. These levels were considerably lower contents than the commercial wine (16-17% v/v) that was produced from this vineyard site. Wines were produced by: (i) harvest timing (19.3, 24 and 29.3 Brix); (ii) blending equal proportions of early harvest (19.3 Brix) and late harvest wines (29.3 Brix); and (iii) dealcoholization using reverse osmosis followed by a membrane contactor. Dealcoholization caused a significant loss of volatile compounds, particularly esters, while the blending treatment had an averaging effect on most analytes. Sensory descriptive analysis of treatments with 10.5% v/v alcohol showed that the perception of the herbaceous attribute was more intense in the early harvest wines in comparison to the dealcoholized wines, while those of dark fruit, raisin/prune, astringency and alcohol were lower. No sensory differences were found amongst the 13.5% v/v wines, except for alcohol. Sensory and compositional data were modelled by means of Common Dimension (ComDim) multi-block analysis and indicated which chemical components are important to the perceived wine sensory properties. Insights from this study will provide knowledge that may be applied to control or moderate both unripe sensory attributes in addition to a deficiency of ripe fruit aromas or mouthfeel characteristics in reduced-alcohol red wines. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Untargeted metabolomic analysis using liquid chromatography quadrupole time-of-flight mass spectrometry for non-volatile profiling of wines

    International Nuclear Information System (INIS)

    Arbulu, M.; Sampedro, M.C.; Gómez-Caballero, A.; Goicolea, M.A.; Barrio, R.J.

    2015-01-01

    Highlights: • An untargeted metabolomic method for the non-volatile profile of the Graciano wine was developed. • 411 different metabolites in Graciano Vitis vinifera red wine were identified. • 15 compounds could serve to differentiate Graciano and Tempranillo wines. • An enological database (WinMet) with 2080 compounds was constructed. - Abstract: The current study presents a method for comprehensive untargeted metabolomic fingerprinting of the non-volatile profile of the Graciano Vitis vinifera wine variety, using liquid chromatography/electrospray ionization time of flight mass spectrometry (LC–ESI-QTOF). Pre-treatment of samples, chromatographic columns, mobile phases, elution gradients and ionization sources, were evaluated for the extraction of the maximum number of metabolites in red wine. Putative compounds were extracted from the raw data using the extraction algorithm, molecular feature extractor (MFE). For the metabolite identification the WinMet database was designed based on electronic databases and literature research and includes only the putative metabolites reported to be present in oenological matrices. The results from WinMet were compared with those in the METLIN database to evaluate how much the databases overlap for performing identifications. The reproducibility of the analysis was assessed using manual processing following replicate injections of Vitis vinifera cv. Graciano wine spiked with external standards. In the present work, 411 different metabolites in Graciano Vitis vinifera red wine were identified, including primary wine metabolites such as sugars (4%), amino acids (23%), biogenic amines (4%), fatty acids (2%), and organic acids (32%) and secondary metabolites such as phenols (27%) and esters (8%). Significant differences between varieties Tempranillo and Graciano were related to the presence of fifteen specific compounds

  15. Untargeted metabolomic analysis using liquid chromatography quadrupole time-of-flight mass spectrometry for non-volatile profiling of wines

    Energy Technology Data Exchange (ETDEWEB)

    Arbulu, M. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Sampedro, M.C. [Central Service of Analysis, SGIker, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Gómez-Caballero, A.; Goicolea, M.A. [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain); Barrio, R.J., E-mail: r.barrio@ehu.es [Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz (Spain)

    2015-02-09

    Highlights: • An untargeted metabolomic method for the non-volatile profile of the Graciano wine was developed. • 411 different metabolites in Graciano Vitis vinifera red wine were identified. • 15 compounds could serve to differentiate Graciano and Tempranillo wines. • An enological database (WinMet) with 2080 compounds was constructed. - Abstract: The current study presents a method for comprehensive untargeted metabolomic fingerprinting of the non-volatile profile of the Graciano Vitis vinifera wine variety, using liquid chromatography/electrospray ionization time of flight mass spectrometry (LC–ESI-QTOF). Pre-treatment of samples, chromatographic columns, mobile phases, elution gradients and ionization sources, were evaluated for the extraction of the maximum number of metabolites in red wine. Putative compounds were extracted from the raw data using the extraction algorithm, molecular feature extractor (MFE). For the metabolite identification the WinMet database was designed based on electronic databases and literature research and includes only the putative metabolites reported to be present in oenological matrices. The results from WinMet were compared with those in the METLIN database to evaluate how much the databases overlap for performing identifications. The reproducibility of the analysis was assessed using manual processing following replicate injections of Vitis vinifera cv. Graciano wine spiked with external standards. In the present work, 411 different metabolites in Graciano Vitis vinifera red wine were identified, including primary wine metabolites such as sugars (4%), amino acids (23%), biogenic amines (4%), fatty acids (2%), and organic acids (32%) and secondary metabolites such as phenols (27%) and esters (8%). Significant differences between varieties Tempranillo and Graciano were related to the presence of fifteen specific compounds.

  16. Production of polyhydroxy alkanoates by Ralstonia eutropha from volatile fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Jung Hyun; Sawant, Shailesh S.; Kim, Beom Soo [Chungbuk National University, Cheongju (Korea, Republic of)

    2013-12-15

    Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics that can be synthesized in various microorganisms. Volatile fatty acids (VFAs) are produced by anaerobic treatment of organic wastes that can be utilized as inexpensive substrates for PHA synthesis. In this study, several Ralstonia eutropha strains were grown on the mixture of VFAs (acetic, propionic, and butyric acid) as its carbon and energy source for growth and PHA synthesis. R. eutropha KCTC 2658 accumulated PHAs up to 50% of dry cell weight from total 5 g/L of mixed VFAs (acetic acid : propionic acid : butyric acid=1 : 2 : 2). In batch culture of R. eutropha KCTC2658 in a 5 L fermentor, a homopolymer of poly(3-hydroxybutyrate) [P(3HB)] was produced from 20 g/L glucose as a sole carbon source with dry cell weight of 8.4 g/L and PHA content of 30%. In fed-batch culture, two feeding strategies, pulse or pH-stat, were applied to add VFAs to the fermentor. When VFAs were fed using pH-stat feeding strategy after 40 h, a copolymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was produced with dry cell weight of 8.1 g/L, PHA content of 50%, and 3HV fraction of 20 mol%.

  17. Cheese milk low homogenization enhanced early lipolysis and volatiles compounds production in hard cooked cheeses.

    Science.gov (United States)

    Vélez, María A; Hynes, Erica R; Meinardi, Carlos A; Wolf, Verónica I; Perotti, María C

    2017-06-01

    Homogenization applied to cheese milk has shown to increase lipolysis but its use is not spread as it can induce detrimental effects. The aim of this work was to assess the effect of low-pressure homogenization of the cream followed by pre-incubation of cheese milk on the composition, ripening index, lipolysis and volatile profiles of hard cooked cheeses. For that, control and experimental miniature Reggianito cheeses were made and analyzed during ripening (3, 45 and 90days). Homogenization had no impact on composition and proteolysis. An acceleration of the lipolysis reaction was clearly noticed in cheeses made with homogenized milk at the beginning of ripening, while both type of cheeses reached similar levels at 90days. We found the level of several compounds derived from fatty acid catabolism were noticeably influenced by the treatment applied: straight-chain aldehydes such as hexanal, heptanal and nonanal and methylketones from C 5 to C 9 were preferentially formed in experimental cheeses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Production of polyhydroxy alkanoates by Ralstonia eutropha from volatile fatty acids

    International Nuclear Information System (INIS)

    Yun, Jung Hyun; Sawant, Shailesh S.; Kim, Beom Soo

    2013-01-01

    Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible thermoplastics that can be synthesized in various microorganisms. Volatile fatty acids (VFAs) are produced by anaerobic treatment of organic wastes that can be utilized as inexpensive substrates for PHA synthesis. In this study, several Ralstonia eutropha strains were grown on the mixture of VFAs (acetic, propionic, and butyric acid) as its carbon and energy source for growth and PHA synthesis. R. eutropha KCTC 2658 accumulated PHAs up to 50% of dry cell weight from total 5 g/L of mixed VFAs (acetic acid : propionic acid : butyric acid=1 : 2 : 2). In batch culture of R. eutropha KCTC2658 in a 5 L fermentor, a homopolymer of poly(3-hydroxybutyrate) [P(3HB)] was produced from 20 g/L glucose as a sole carbon source with dry cell weight of 8.4 g/L and PHA content of 30%. In fed-batch culture, two feeding strategies, pulse or pH-stat, were applied to add VFAs to the fermentor. When VFAs were fed using pH-stat feeding strategy after 40 h, a copolymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was produced with dry cell weight of 8.1 g/L, PHA content of 50%, and 3HV fraction of 20 mol%

  19. pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.

    Science.gov (United States)

    Xie, Li; Liu, Hui; Chen, Yin-Guang; Zhou, Qi

    2014-01-01

    Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.

  20. Short time ahead wind power production forecast

    International Nuclear Information System (INIS)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-01-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast. (paper)

  1. Short time ahead wind power production forecast

    Science.gov (United States)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-09-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast.

  2. Development of Solid Ceramic Dosimeters for the Time-Integrative Passive Sampling of Volatile Organic Compounds in Waters.

    Science.gov (United States)

    Bonifacio, Riza Gabriela; Nam, Go-Un; Eom, In-Yong; Hong, Yong-Seok

    2017-11-07

    Time-integrative passive sampling of volatile organic compounds (VOCs) in water can now be accomplished using a solid ceramic dosimeter. A nonporous ceramic, which excludes the permeation of water, allowing only gas-phase diffusion of VOCs into the resin inside the dosimeter, effectively captured the VOCs. The mass accumulation of 11 VOCs linearly increased with time over a wide range of aqueous-phase concentrations (16.9 to 1100 μg L -1 ), and the linearity was dependent upon the Henry's constant (H). The average diffusivity of the VOCs in the solid ceramic was 1.46 × 10 -10 m 2 s -1 at 25 °C, which was 4 orders of magnitude lower than that in air (8.09 × 10 -6 m 2 s -1 ). This value was 60% greater than that in the water-permeable porous ceramic (0.92 × 10 -10 m 2 s -1 ), suggesting that its mass accumulation could be more effective than that of porous ceramic dosimeters. The mass accumulation of the VOCs in the solid ceramic dosimeter increased in the presence of salt (≥0.1 M) and with increasing temperature (4 to 40 °C) but varied only slightly with dissolved organic matter concentration. The solid ceramic dosimeter was suitable for the field testing and measurement of time-weighted average concentrations of VOC-contaminated waters.

  3. Continuous volatile fatty acid production from lignocellulosic biomass by a novel rumen-mimetic bioprocess.

    Science.gov (United States)

    Agematu, Hitosi; Takahashi, Takehiko; Hamano, Yoshio

    2017-11-01

    Lignocellulosic biomass is an attractive source of biofuels and biochemicals, being abundant in various plant sources. However, processing this type of biomass requires hydrolysis of cellulose. The proposed rumen-mimetic bioprocess consists of dry-pulverization of lignocellulosic biomass and pH-controlled continuous cultivation of ruminal bacteria using ammonium as a nitrogen source. In this study, ruminal bacteria were continuously cultivated for over 60 days and used to digest microcrystalline cellulose, rice straw, and Japanese cedar to produce volatile fatty acids (VFAs). The ruminal bacteria grew well in the chemically defined medium. The amounts of VFAs produced from 20 g of cellulose, rice straw, and Japanese cedar were 183 ± 29.7, 69.6 ± 12.2, and 21.8 ± 12.9 mmol, respectively. Each digestion completed within 24 h. The carbon yield was 60.6% when 180 mmol of VFAs was produced from 20 g of cellulose. During the cultivation, the bacteria were observed to form flocs that enfolded the feed particles. These flocs likely contain all of the bacterial species necessary to convert lignocellulosic biomass to VFAs and microbial protein symbiotically. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rDNA fragments revealed that the bacterial community was relatively stable after 1 week in cultivation, though it was different from the original community structure. Furthermore, sequence analysis of the DGGE bands indicates that the microbial community includes a cellulolytic bacterium, a bacterium acting synergistically with cellulolytic bacteria, and a propionate-producing bacterium, as well as other anaerobic bacteria. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Volatile Composition and Enantioselective Analysis of Chiral Terpenoids of Nine Fruit and Vegetable Fibres Resulting from Juice Industry By-Products

    Directory of Open Access Journals (Sweden)

    Alexis Marsol-Vall

    2017-01-01

    Full Text Available Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging from 52.7% in lemon to 94.0% in tangerine flesh. Noncitrus fibres showed more variable compositions, with the predominant classes being aldehydes in apple (57.5% and peach (69.7%, esters (54.0% in pear, and terpenoids (35.3% in carrot fibres. In addition, enantioselective analysis of some of the chiral terpenoids present in the fibre revealed that the enantiomeric ratio for selected compounds was similar to the corresponding volatile composition of raw fruits and vegetables and some derivatives, with the exception of terpinen-4-ol and α-terpineol, which showed variation, probably due to the drying process. The processing to which fruit residues were submitted produced fibres with low volatile content for noncitrus products. Otherwise, citrus fibres analysed still presented a high volatile composition when compared with noncitrus ones.

  5. Fast computation of vanilla prices in time-changed models and implied volatilities using rational approximations

    NARCIS (Netherlands)

    Pistorius, M.; Stolte, J.

    2012-01-01

    We present a new numerical method to price vanilla options quickly in time-changed Brownian motion models. The method is based on rational function approximations of the Black-Scholes formula. Detailed numerical results are given for a number of widely used models. In particular, we use the

  6. Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets

    NARCIS (Netherlands)

    Etienne, Xiaoli L.; Trujillo-Barrera, Andrés; Hoffman, Linwood A.

    2017-01-01

    We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic

  7. Production, staff, working time and financial planning

    Directory of Open Access Journals (Sweden)

    Orlando Boiteux

    2009-07-01

    Full Text Available Aggregate planning can be a tool for coordinating the tactical decisions belonging to some functional areas of a company. This potential has been limited due to methodological and technical reasons, but nowadays it is possible to solve very sophisticated models integrating, with a high level of detail, a great number of decisions of several functional areas and that permit to include new management schemes. In this paper, a production, staff, working time and cash management model is introduced.

  8. Identification of volatile organic compounds (VOCs in plastic products using gas chromatography and mass spectrometry (GC/MS

    Directory of Open Access Journals (Sweden)

    Nerlis Pajaro-Castro

    2014-10-01

    Full Text Available Plastic materials are widely used in daily life. They contain a wide range of compounds with low molecular mass, including monomeric and oligomeric residues of polymerization, solvent-related chemicals residues, and various additives. Plastic products made of expanded polystyrene (EPS are currently employed as food containers. This study therefore sought to identify volatile organic compounds released by EPS from food packages and utensils used in Cartagena, Colombia. EPS-based plates, food and soup containers were subjected to various temperatures and released chemicals captured by solid phase microextraction, followed by on-column thermal desorption and gas chromatography/mass spectrometry analysis. The results revealed the presence of at least 30 different compounds in the EPS-based products examined; the most frequently found were benzaldehyde, styrene, ethylbenzene and tetradecane. The release of these molecules was temperature-dependent. It is therefore advisable to regulate the use of EPS products which may be subjected to heating in order to protect human health by decreasing the exposure to these chemicals.

  9. Feed-derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows.

    Science.gov (United States)

    Tsunoda, Ei; Gross, Josef J; Kawashima, Chiho; Bruckmaier, Rupert M; Kida, Katsuya; Miyamoto, Akio

    2017-01-01

    The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid-VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow. © 2016 Japanese Society of Animal Science.

  10. 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.

  11. Oleaginous yeast Yarrowia lipolytica culture with synthetic and food waste-derived volatile fatty acids for lipid production.

    Science.gov (United States)

    Gao, Ruiling; Li, Zifu; Zhou, Xiaoqin; Cheng, Shikun; Zheng, Lei

    2017-01-01

    The sustainability of microbial lipids production from traditional carbon sources, such as glucose or glycerol, is problematic given the high price of raw materials. Considerable efforts have been directed to minimize the cost and find new alternative carbon sources. Volatile fatty acids (VFAs) are especially attractive raw materials, because they can be produced from a variety of organic wastes fermentation. Therefore, the use of volatile fatty acids as carbon sources seems to be a feasible strategy for cost-effective microbial lipid production. Lipid accumulation in Y. lipolytica using synthetic and food waste-derived VFAs as substrates was systematically compared and evaluated in batch cultures. The highest lipid content obtained with acetic, butyric, and propionic acids reached 31.62 ± 0.91, 28.36 ± 0.74, and 28.91 ± 0.66%, respectively. High concentrations of VFA inhibited cell growth in the following order: butyric acid > propionic acid > acetic acid. Within a 30-day experimental period, Y. lipolytica could adapt up to 20 g/L acetic acid, whereas the corresponding concentration of propionic acid and butyric acid were 10 and 5 g/L, respectively. Cultures on a VFA mixture showed that the utilization of different types of VFA by Y. lipolytica was not synchronized but rather performed in a step-wise manner. Although yeast fermentation is an exothermic process, and the addition of VFA will directly affect the pH of the system by increasing environmental acidity, cultures at a cultivation temperature of 38 °C and uncontrolled pH demonstrated that Y. lipolytica had high tolerance in the high temperature and acidic environment when a low concentration (2.5 g/L) of either synthetic or food waste-derived VFA was used. However, batch cultures fed with food fermentate yielded lower lipid content (18.23 ± 1.12%) and lipid productivity (0.12 ± 0.02 g/L/day). The lipid composition obtained with synthetic and food waste-derived VFA was similar to

  12. On the composition of volatiles evolved during the production of carbon adsorbents from vegetable wastes

    Energy Technology Data Exchange (ETDEWEB)

    Razvigorova, M; Goranova, M; Minkova, V; Cerny, J [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Organic Chemistry with Center of Phytochemistry

    1994-11-01

    Gas and liquid products evolved in the process of carbon adsorbent production by steam pyrolysis of apricot stones and coconut shells are investigated. The oils are separated by an extrographic procedure, and the obtained fractions are analysed by gas chromatography-mass spectrometry. The basic part of the identified compounds are derivatives of phenol, guaiacol, veratrol, syringol, resorcinol, free fatty acids and esters of fatty acids. The comparative study of the pyrolysis products of apricot stones and coconut shells reveals some differences, referring mainly to the lipid parts of the raw materials. 17 refs., 1 fig., 6 tabs.

  13. The investment in scent: time-resolved metabolic processes in developing volatile-producing Nigella sativa L. seeds.

    Directory of Open Access Journals (Sweden)

    Wentao Xue

    Full Text Available The interplay of processes in central and specialized metabolisms during seed development of Nigella sativa L. was studied by using a high-throughput metabolomics technology and network-based analysis. Two major metabolic shifts were identified during seed development: the first was characterized by the accumulation of storage lipids (estimated as total fatty acids and N-compounds, and the second by the biosynthesis of volatile organic compounds (VOCs and a 30% average decrease in total fatty acids. Network-based analysis identified coordinated metabolic processes during development and demonstrated the presence of five network communities. Enrichment analysis indicated that different compound classes, such as sugars, amino acids, and fatty acids, are largely separated and over-represented in certain communities. One community displayed several terpenoids and the central metabolites, shikimate derived amino acids, raffinose, xylitol and glycerol-3-phosphate. The latter are related to precursors of the mevalonate-independent pathway for VOC production in the plastid; also plastidial fatty acid 18∶3n-3 abundant in "green" seeds grouped with several major terpenes. The findings highlight the interplay between the components of central metabolism and the VOCs. The developmental regulation of Nigella seed metabolism during seed maturation suggests a substantial re-allocation of carbon from the breakdown of fatty acids and from N-compounds, probably towards the biosynthesis of VOCs.

  14. The Price Volatility of Precious Metals in Times of Economic and Geopolitical Crisis

    Directory of Open Access Journals (Sweden)

    Viorel Mionel

    2017-09-01

    Full Text Available People perceive gold, silver and platinum as jewellery and massive ingots, but their rarity and physicochemical properties recommend them as being suitable for a wide range of uses. The value of gold has led many states to diversify their economic portfolio by creating sovereign reserves. By buying massive amounts of gold, countries like China, Russia, India, Brazil and Turkey suggest that the purchase of precious metals is the best investment during the crisis. Research results show that the value of precious metals greatly increases at times of crisis because buying precious metals indemnifies states against international currency devaluation.

  15. Production of active charcoal and characteristic of volatile organic compounds in condensate

    International Nuclear Information System (INIS)

    Lalik, V.; Knoskova, L.

    2005-01-01

    In the last decade a production of charcoal and products from charcoal has been taking on an important position in a field of environmental technologies. Technological process of the production of charcoal is accompanied by formation of fluid and gaseous elements. These elements are ranked as pollutants from the legal point of view. There are mainly carbon dioxide and carbon monoxide and other oxide compounds from the chemical point of view. Particularly acetic acid, methanol, 2-furaldehyde. Then aliphatic alcohols, phenols, aldehydes, ketones, esters and other groups of substances. Law limits the quantity and concentration of these essentials emitted into the open air. This matter has to be taken care of during the production of charcoal. It is usually solved by condensation cooling and following burning gases and steams. Condensate is industrially processed or smaller technologies handle with it similar to taking care of wastewater. (authors)

  16. GC-FTIR-MS analysis of volatile radiolytic products in the radiolysis of nitroaniline

    International Nuclear Information System (INIS)

    Kuruc, J.; Sahoo, M.K.; Kubinec, R.

    1993-01-01

    A good deal of products formed in the γ-radiolysis of isomeric nitroaniline solutions in carbon tetrachloride have been identified using GC-FTIR-MS technique. Tetrachloroethylene, chlorobenzene, hexachloroethane isomeric di-, tri- and tetrachlorobenzenes and chloroisocyanatobenzenes are among the important products formed in the radiolysis. Formation of dichlorobenzene is the result of ipso-substitution of both the nitro and aniline group by chlorine atom and the subsequent chloration of dichlorobenzene results in the formation of polychlorobenzenes. Chloroisocyanatobenzene is proposed to be the product arising from the interaction of dichlorocarbene and the nitro group of nitroaniline followed by chlorination of the resulting product, isocyanatobenzene. A 94% yield of undissolved 1,2-aminonitrobenzene chloride salt is obtained from the radiolysis of o-nitroaniline solution in carbon tetrachloride with a radiation yield of 1.83 molecules per 100 eV absorbed energy for an irradiation dose of 267 kGy. (author) 9 refs.; 3 figs.; 2 tabs

  17. Health evaluation of volatile organic compound (VOC) emission from exotic wood products

    DEFF Research Database (Denmark)

    Kirkeskov, L; Witterseh, T; Funch, L W

    2009-01-01

    The purpose of this study was to measure and evaluate the impact of the emissions of selected products of exotic wood on health. Ten products were screened for chemical compounds, and five of the most used products which emitted more than 800 microg/kg were selected for further quantitative...... analyses by climate chamber measurement (iroko, ramin, sheesham, merbau, and rubber tree). Samples of exotic wood (rubber tree and belalu) were further analyzed for emission of chemical compounds by migration into artificial saliva and for content of pesticides and allergenic natural rubber latex (NR latex......) (rubber tree). The toxicological effects of all substances identified were evaluated and the lowest concentrations of interest (LCI) assessed. An R-value was calculated for each wood product (R-value below 1 is considered to be unproblematic as regards health). Emission from the evaluated exotic wood only...

  18. Temperature-dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry.

    Science.gov (United States)

    Maleknia, Simin D; Vail, Teresa M; Cody, Robert B; Sparkman, David O; Bell, Tina L; Adams, Mark A

    2009-08-01

    A method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time-of-flight (TOF) mass spectrometer. Temperature-dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300 degrees C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue-specific transport and emissions of VOCs. Copyright (c) 2009 John Wiley & Sons, Ltd.

  19. Changes in ruminal volatile fatty acid production and absorption rate during the dry period and early lactation as affected by rate of increase of concentrate allowance

    NARCIS (Netherlands)

    Dieho, K.; Dijkstra, J.; Schonewille, J. T.; Bannink, A.

    The aim of the present experiment was to study changes in volatile fatty acid (VFA) production using an isotope dilution technique, and changes in VFA fractional absorption rate (k aVFA) using a buffer incubation technique (BIT) during the dry period and early lactation, as affected by the

  20. Volatile compounds and phenolic composition of virgin olive oil: optimization of temperature and time of exposure of olive pastes to air contact during the mechanical extraction process.

    Science.gov (United States)

    Servili, Maurizio; Selvaggini, Roberto; Taticchi, Agnese; Esposto, Sonia; Montedoro, GianFrancesco

    2003-12-31

    The operative conditions of malaxation such as temperature and time of exposure of olive pastes to air contact (TEOPAC) affect volatile and phenolic composition of virgin olive oil (VOO) and, as a consequence, its sensory and healthy qualities. In this paper, optimal temperature and TEOPAC during malaxation were studied, in lab scale, in two Italian cultivars using phenolic compounds, volatile composition, and sensory analysis of VOO as markers. The optimal temperature and TEOPAC, selected by response surface modeling,were cultivar-dependent being 30 min of TEOPAC at the lowest temperature investigated (22 degrees C) and 0 min of TEOPAC at 26 degrees C for Frantoio and Moraiolo cultivars, respectively.

  1. 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.

  2. Effects of daylight-saving time changes on stock market volatility: a comment.

    Science.gov (United States)

    Kamstra, Mark J; Kramer, Lisa A; Levi, Maurice D

    2010-12-01

    In a recent article in this journal, Berument, Dogan, and Onar (2010) challenged the existence of the previously documented daylight-saving effect. Kamstra, Kramer, and Levi's original finding (2000) was that average stock market returns on Mondays following time changes are economically and statistically significantly lower than typical Monday returns. Kamstra, et al. hypothesized that the effect may arise due to heightened anxiety or risk aversion on the part of market participants after they experience a 1-hr. disruption in their sleep habits, in accordance with prior findings in the psychology literature linking sleep desynchronosis with anxiety. Berument, et al. replicated the original findings using ordinary least squares estimation, but when they modeled the mean of returns using a method prone to producing biased estimates, they obtained puzzling results. The analysis here, based on standard, unbiased modeling techniques, shows that the daylight-saving effect remains intact in the U.S.

  3. Volatility persistence in crude oil markets

    International Nuclear Information System (INIS)

    Charles, Amélie; Darné, Olivier

    2014-01-01

    Financial market participants and policy-makers can benefit from a better understanding of how shocks can affect volatility over time. This study assesses the impact of structural changes and outliers on volatility persistence of three crude oil markets – Brent, West Texas Intermediate (WTI) and Organization of Petroleum Exporting Countries (OPEC) – between January 2, 1985 and June 17, 2011. We identify outliers using a new semi-parametric test based on conditional heteroscedasticity models. These large shocks can be associated with particular event patterns, such as the invasion of Kuwait by Iraq, the Operation Desert Storm, the Operation Desert Fox, and the Global Financial Crisis as well as OPEC announcements on production reduction or US announcements on crude inventories. We show that outliers can bias (i) the estimates of the parameters of the equation governing volatility dynamics; (ii) the regularity and non-negativity conditions of GARCH-type models (GARCH, IGARCH, FIGARCH and HYGARCH); and (iii) the detection of structural breaks in volatility, and thus the estimation of the persistence of the volatility. Therefore, taking into account the outliers on the volatility modelling process may improve the understanding of volatility in crude oil markets. - Highlights: • We study the impact of outliers on volatility persistence of crude oil markets. • We identify outliers and patches of outliers due to specific events. • We show that outliers can bias (i) the estimates of the parameters of GARCH models, (ii) the regularity and non-negativity conditions of GARCH-type models, (iii) the detection of structural breaks in volatility of crude oil markets

  4. Decomposition of three volatile organic compounds by nanosecond pulsed corona discharge: Study of by-product formation and influence of high voltage pulse parameters

    Science.gov (United States)

    Jarrige, Julien; Vervisch, Pierre

    2006-06-01

    Increasing concerns over atmospheric pollution has motivated research into technologies able to remove volatile organic compounds (VOC's) from gas streams. The aim of this paper is to understand the chemical and physical mechanisms implied in the decomposition of VOC's in a filamentary nonthermal plasma discharge. Experiments have been carried out on three pollutants (propane, propene, and isopropyl alcohol) in dry air at atmospheric pressure using a wire to cylinder corona discharge generated by a homemade nanosecond rise time high voltage pulse generator. The resulting plasma efficiently destructs propane, propene, or isopropyl alcohol at a concentration of 500 ppm with low specific input energies (less than 500 J/L), but the poor oxidation rate leads to the formation of numerous by-products (acetone, formaldehyde, formic acid, and methyl nitrate) whose concentration can reach some hundreds of ppm. We also investigated the effect of pulse parameters on VOC removal efficiency. Neither pulse peak value nor rise time (in the range of 4-12 ns) appears to have a significant influence on the VOC decomposition rates. Therefore, we believe that the way the energy is deposited in the plasma does not modify the density of active species (radicals, ions) in the streamers. The production of energetic electrons is not enhanced by the external applied field, and the only effective parameter may be the local field in the streamer head, which is almost the same (around 500 Td) whatever the voltage (above the inception value).

  5. Decomposition of three volatile organic compounds by nanosecond pulsed corona discharge: Study of by-product formation and influence of high voltage pulse parameters

    International Nuclear Information System (INIS)

    Jarrige, Julien; Vervisch, Pierre

    2006-01-01

    Increasing concerns over atmospheric pollution has motivated research into technologies able to remove volatile organic compounds (VOC's) from gas streams. The aim of this paper is to understand the chemical and physical mechanisms implied in the decomposition of VOC's in a filamentary nonthermal plasma discharge. Experiments have been carried out on three pollutants (propane, propene, and isopropyl alcohol) in dry air at atmospheric pressure using a wire to cylinder corona discharge generated by a homemade nanosecond rise time high voltage pulse generator. The resulting plasma efficiently destructs propane, propene, or isopropyl alcohol at a concentration of 500 ppm with low specific input energies (less than 500 J/L), but the poor oxidation rate leads to the formation of numerous by-products (acetone, formaldehyde, formic acid, and methyl nitrate) whose concentration can reach some hundreds of ppm. We also investigated the effect of pulse parameters on VOC removal efficiency. Neither pulse peak value nor rise time (in the range of 4-12 ns) appears to have a significant influence on the VOC decomposition rates. Therefore, we believe that the way the energy is deposited in the plasma does not modify the density of active species (radicals, ions) in the streamers. The production of energetic electrons is not enhanced by the external applied field, and the only effective parameter may be the local field in the streamer head, which is almost the same (around 500 Td) whatever the voltage (above the inception value)

  6. The Volatility of Long-term Bond Returns: Persistent Interest Shocks and Time-varying Risk Premiums

    DEFF Research Database (Denmark)

    Osterrieder, Daniela; Schotman, Peter C.

    We develop a model that can match two stylized facts of the term-structure. The first stylized fact is the predictability of excess returns on long-term bonds. Modeling this requires sufficient volatility and persistence in the price of risk. The second stylized fact is that long-term yields...... are dominated by a level factor, which requires persistence in the spot interest rate. We find that a fractionally integrated process for the short rate plus a fractionally integrated specification for the price of risk leads to an analytically tractable almost affine term structure model that can explain...... the stylized facts. In a decomposition of long-term bond returns we find that the expectations component from the level factor is more volatile than the returns themselves. It therefore takes a volatile risk premium that is negatively correlated with innovations in the level factor to explain the volatility...

  7. Volatile N-nitrosamines in meat products: Potential precursors, influence of processing, and mitigation strategies.

    Science.gov (United States)

    De Mey, Eveline; De Maere, Hannelore; Paelinck, Hubert; Fraeye, Ilse

    2017-09-02

    Meat products can be contaminated with carcinogenic N-nitrosamines, which is ascribed to the reaction between a nitrosating agent, originating from nitrite or smoke, and a secondary amine, derived from protein and lipid degradation. Although in model systems it is demonstrated that many amine containing compounds can be converted to N-nitrosamines, the yield is dependent of reaction conditions (e.g., low pH and high temperature). In this article, the influence of the composition of the meat products (e.g., pH, a w , spices) and processing (e.g., ageing, ripening, fermentation, smoking, heat treatment and storage) on the presence and availability of the amine precursors and the N-nitrosamine formation mechanism is discussed. In addition, this article explores the current N-nitrosamine mitigation strategies in order to obtain healthier and more natural meat products.

  8. [Analysis of volatile sulfur compounds production of oral cavity in preschool children and influencing factors].

    Science.gov (United States)

    Zhang, Qun; Liu, Xue-nan; Chang, Qing; Ao, Shuang; Zheng, Shu-guo; Xu, Tao

    2015-12-18

    To investigate the prevalence of volatile sulfur compounds(VSC) in oral cavity of preschool children, and to analyze related factors, thus to provide scientific basis for the prediction and treatment of halitosis. The VSC content (hydrogen sulfide, methyl mercaptan, dimethyl sulfide) of 170 preschool children (4 to 6 years old) was detected by a portable gas chromatograph OralChromaTM. The status of the oral health was evaluated. The living habits and other aspects were obtained through questionnaires from the children's parents. A soft package for social statistics version 13.0 (SPSS 13.0) was used in which univariate analysis and multivariate analysis were utilized to analyze the related factors of halitosis in children. In the study, 34.4% of the total subjects had excessive VSC. Hydrogen sulfide (H₂S) [(1.59 ± 2.41) ng/10 mL] and total VSC concentration [(2.14 ± 4.42) ng/10 mL] in the girls were significantly higher (P<0.05) than those in the boys. The tongue coating score had a significant positive correlation with H2S [tongue coating area (1.68 ± 2.48) ng/10 mL,tongue coating thickness (2.18 ± 2.69) ng/10 mL] and total VSC concentration [tongue coating area, (2.26 ± 4.31) ng/10 mL,tongue coating thickness (2.41 ± 3.02) ng/10 mL , P<0.01]. The site number of DI-S ≥ 2 had a significant positive correlation with methyl mercaptan (CH3SH) and dimethyl sulfide [(CH3)2S] concentration (P<0.01). The concentration of H₂S [(1.19 ± 1.62) ng/10 mL] in children, whose mother had a higher degree of education, was statistically lower (P<0.01). The children who took dessert or sweat drinks more frequently had lower H2S [(1.04 ± 1.55) ng/10 mL, P<0.05] concentration, while CH3SH and (CH3₂)S concentration [(0.29 ± 1.92) ng/10 mL, (0.37 ± 2.06) ng/10 mL, P<0.05) were higher in the children with mouth-breath habit. A high prevalence of halitosis was noted in preschool children. Gender, tongue coating index, debris index-simplified, status of the mother

  9. Volatile fatty acids production in the rumen of young heifers given diets containing a large proportion of concentrate

    International Nuclear Information System (INIS)

    Oshio, Shuichi; Tahata, Ichiro; Kobayashi, Haruo; Ami, Tsuyako

    1977-01-01

    The rate of production of volatile fatty acids (VFA) in the rumen of animals on high concentrate feeding was studied with eighteen young heifers fitted with a permanent rumen fistula, using a single injection method of 14 C-acetate and polyethylene glycol (PEG) in order to get some basic informations of rumen fermentation on concentrate diets. The results obtained were as follows; 1) The pH value, total VFA concentration, and proportion of each acid on all-concentrate diets showed distinguished differences in comparison with those of the animals fed a large proportion of hay, but varied widely between days and heifers. 2) VFA proportions were significantly correlated with pH. At the pH value of about 5.2, acetic acid was minimum, and propionic acid and valeric acid were maximum in molar proportion. 3) It was suggested that, in the case of all-concentrate feeding for a long period, the VFA production in the rumen was depressed to 33.5-41% of digestible energy. In the animals fed hay and concentrate, the percentage was about 50%. (auth.)

  10. Enhancement of acidogenic fermentation for volatile fatty acid production from food waste: Effect of redox potential and inoculum.

    Science.gov (United States)

    Yin, Jun; Yu, Xiaoqin; Zhang, Yeer; Shen, Dongsheng; Wang, Meizhen; Long, Yuyang; Chen, Ting

    2016-09-01

    The aim of this study was to explore the effects of redox potential (ORP) and inoculum on volatile fatty acids (VFAs) production from food waste by acidogenic fermentation. Four experimental conditions with two ORP levels were tested: limited aeration conditions with ORP level of -100 to -200mV inoculating anaerobic sludge (LA+AnS) or aerobic sludge (LA+AeS), and anaerobic conditions with ORP level of -200 to -300mV inoculating anaerobic sludge with 2-bromoethanosulfophate (AN+BES) and without BES (AN). The maximal VFA yield (0.79g COD/g VS) was attained in LA+AnS reactor due to enhanced hydrolysis of substrates, especially proteins (degradation efficiency 78.3%). A higher frequency of phylum Firmicutes under limited aeration conditions (42.2-48.2%) was observed than that under anaerobic conditions (21.1%). The microbial community was more diverse in LA+AnS reactors than LA+AeS. We conclude that appropriate ORP level (from -100 to -200mV) and inoculum play essential roles in VFA production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Antifungal activity of volatile compounds generated by essential oils against fungi commonly causing deterioration of bakery products.

    Science.gov (United States)

    Guynot, M E; Ramos, A J; Setó, L; Purroy, P; Sanchis, V; Marín, S

    2003-01-01

    To investigate the volatile fractions of 16 essential oils for activity against the more common fungi causing spoilage of bakery products, Eurotium amstelodami, E. herbariorum, E. repens, E. rubrum, Aspergillus flavus, A. niger and Penicillium corylophilum. The study applied 50 microl of pure essential oils in a sterilized filter paper, were carried out at pH 6 and at different water activity levels (0.80-0.90). First, a wheat flour based agar medium was used, where cinnamon leaf, clove, bay, lemongrass and thyme essential oils where found to totally inhibit all microorganisms tested. These five essential oils were then tested in sponge cake analogues, but the antifungal activity detected was much more limited. Five essential oils showed potential antifungal capacity against all species tested, over a wide range of water availability. Their activity, however, seems to be substrate-dependent. More research is needed to make them work in real bakery products, as in the preliminary study limited effectiveness was found. The potential of the cinnamon leaf, clove, bay, lemongrass and thyme essential oils against species belonging to Eurotium, Aspergillus and Penicillium genus has been demonstrated.

  12. Simulation Analysis of Sludge Disposal and Volatile Fatty Acids Production from Gravity Pressure Reactor via Wet Air Oxidation

    International Nuclear Information System (INIS)

    Park, Gwon Woo; Seo, Tae Wan; Lee, Hong-Cheol; Hwang, In-Ju

    2016-01-01

    Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively

  13. Studies concerning the production of volatile oil, rhizomes and roots, to different genotypes of Valeriana officinalis L.

    Directory of Open Access Journals (Sweden)

    Mihai Radu POP

    2010-11-01

    Full Text Available Valeriana officinalis L. is considered to pertain to European species, with great ecologic plasticity, which allows its adaptation to climate conditions characteristics to plain areas and also to mountain areas up to an altitude of 2400 meters. The species is a well-known curative plant, with a long history and multiple uses. Essential oils deriving from this species revealed the interest of researchers in food industry, cosmetics and officinal industry, furthermore being used as additives too.The raw material from which essential oils are being extracted is represented mainly by rhizomes and roots. This study has the purpose to emphasize the differences of essential oils production registered based upon the genotypes diversity. Thus, 11 experimental variants have been used, with biologic material of different origin, from Romania, Poland, Germany and Russia; they have been measured in relation to their production of rhizomes, roots and volatile oil, in the ecological conditions of Brasov, Romania.The results proved the superiority of the variants was used Romanian variety M-100, but have also revealed a negative correlation between capacity and essential oil biosynthesis.

  14. Simulation Analysis of Sludge Disposal and Volatile Fatty Acids Production from Gravity Pressure Reactor via Wet Air Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gwon Woo [Biomass and Waste Energy Laboratory, KIER, Daejeon (Korea, Republic of); Seo, Tae Wan; Lee, Hong-Cheol; Hwang, In-Ju [Environmental and Plant Engineering Research Institute, KICT, Goyang (Korea, Republic of)

    2016-04-15

    Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

  15. Characterization of biosynthetic pathways for the production of the volatile homoterpenes DMNT and TMTT in Zea mays

    Science.gov (United States)

    Plant volatiles not only have multiple defense functions against herbivores, fungi, and bacteria, but also have been implicated in signaling within the plant and toward other organisms. Elucidating the function of individual plant volatiles will require more knowledge of their biosynthesis and regul...

  16. ‘Fuji’ apple (Malus domestica Borkh) volatile production during high pCO2 controlled atmosphere storage

    Science.gov (United States)

    ‘Fuji’apple [Malus sylvestris var. domestica (Borkh.) Mansf.] volatile compound dynamics were characterized during cold storage in air or at low pO2 controlled atmosphere (CA) with up to 5 kPa CO2. Volatile compounds in storage chambers were adsorbed onto solid sorbent traps and analyzed by GC-MS....

  17. Degradation products of citrus volatile organic compounds (VOCs) acting as phagostimulants that increase probing behavior of Asian citrus psyllid

    Science.gov (United States)

    Volatile phytochemicals play a role in orientation by phytophagous insects. We studied antennal and behavioral responses of the Asian citrus psyllid, Diaphorina citri Kuwayama, vector of the citrus greening disease pathogen. Little or no response to citrus leaf volatiles was detected by electroanten...

  18. Volatile production during preignition heating. Final technical report, 15 September 1980-30 September 1982

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, A.; Chou, H.; Flusberg, A.; Neoh, K.; Orozco, N.; Stickler, D.

    1983-10-01

    Pulverized coal particles, in a flowing inert nitrogen stream, have been heated by high power Carbon Dioxide Laser. The consequence of such an irradiation have proved to be both novel and surprising as a result of the rapid quenching of primary coal products. It ahs been found that the gas phase yield from such heating (typically, temperatures in excess of 1400 K at rates approx. 2 x 10/sup 5/ K/s) is very small (< 0.2 percent of coal carbon and hydrogen). Analysis of the solid residue has shown the presence of fine lacy particulate chains of material of 0.1 ..mu..m diameter, which appears to be soluble in tetrahydrofuran. The yields of solute were significantly much higher than for raw coals. Molecular weight of the solute material was high, being in the range of 600 to 3000. The above and substantiating evidence point to a new mechanism of high heating rate pyrolysis in which only tar-like materials are produced as primary products from the coal. It is hypothesized that gas phase products are primarily the result of secondary reactions of these primary products in the hot gas environments usually employed by other heating techniques.

  19. Experimental determination of the partitioning coefficient and volatility of important BVOC oxidation products using the Aerosol Collection Module (ACM) coupled to a PTR-ToF-MS

    Science.gov (United States)

    Gkatzelis, G.; Hohaus, T.; Tillmann, R.; Schmitt, S. H.; Yu, Z.; Schlag, P.; Wegener, R.; Kaminski, M.; Kiendler-Scharr, A.

    2015-12-01

    Atmospheric aerosol can alter the Earth's radiative budget and global climate but can also affect human health. A dominant contributor to the submicrometer particulate matter (PM) is organic aerosol (OA). OA can be either directly emitted through e.g. combustion processes (primary OA) or formed through the oxidation of organic gases (secondary organic aerosol, SOA). A detailed understanding of SOA formation is of importance as it constitutes a major contribution to the total OA. The partitioning between the gas and particle phase as well as the volatility of individual components of SOA is yet poorly understood adding uncertainties and thus complicating climate modelling. In this work, a new experimental methodology was used for compound-specific analysis of organic aerosol. The Aerosol Collection Module (ACM) is a newly developed instrument that deploys an aerodynamic lens to separate the gas and particle phase of an aerosol. The particle phase is directed to a cooled sampling surface. After collection particles are thermally desorbed and transferred to a detector for further analysis. In the present work, the ACM was coupled to a Proton Transfer Reaction-Time of Flight-Mass Spectrometer (PTR-ToF-MS) to detect and quantify organic compounds partitioning between the gas and particle phase. This experimental approach was used in a set of experiments at the atmosphere simulation chamber SAPHIR to investigate SOA formation. Ozone oxidation with subsequent photochemical aging of β-pinene, limonene and real plant emissions from Pinus sylvestris (Scots pine) were studied. Simultaneous measurement of the gas and particle phase using the ACM-PTR-ToF-MS allows to report partitioning coefficients of important BVOC oxidation products. Additionally, volatility trends and changes of the SOA with photochemical aging are investigated and compared for all systems studied.

  20. Acid fermentation of municipal sludge: the effect of sludge type and origin on the production and composition of volatile fatty acids

    International Nuclear Information System (INIS)

    Ucisik, A. S.; Schmidit, J. E.; Henze, M.

    2009-01-01

    Due to the more stringent legislations controlling discharges of wastewater treatment plants (WWTPs) and existing problems such as high sludge production, new wastewater treatment processes resulting in considerably reduced sludge production and more effective treatment would be of great value. In this study, the feasibility of implementing acid fermentation process on different types of municipal sludge to increase soluble chemical oxygen demand (SCOD), especially short-chain volatile fatty acids (VFAs) was investigated by batch and semi-continuous experiments. (Author)

  1. Production of gas and volatile materials by distillation of tars, etc

    Energy Technology Data Exchange (ETDEWEB)

    Arson, M

    1860-04-25

    The principle of this production is in the treating of heavy oils with heat, their transformation occurring nearly completely by the action of this agent. The apparatus used consists of a retort of such a form that it has openings at the two ends immediately opposed to each other. One serves to introduce the oil and the other to remove the tar and gas produced. At the exit of the apparatus the gas passes into coolers like those used for coal gas.

  2. Heterogeneous processing of biomass burning aerosol proxies by OH radicals for a wide range of OH concentrations and detection of volatilization products

    Science.gov (United States)

    Slade, J. H.; Knopf, D. A.

    2012-12-01

    Biomass burning aerosol (BBA) constitutes the majority of primary organic aerosol found in the atmosphere, with emission rates comparable to fossil-fuel burning. BBA affects earth's radiative budget directly through absorption and scattering of radiation or indirectly by modifying cloud radiative properties, and impacts air quality. Quantifying BBA source strength and thus its effects on air quality, human health, and climate can be difficult since these organic particles can chemically transform during atmospheric transport, a process also termed aging, due to heterogeneous reactions with oxidants and radicals such as OH. In this work we investigate the reactive uptake of OH radicals by typical BBA compounds that also serve as molecular markers for source apportionment studies. Organic substrates of cellulose pyrolysis products such as levoglucosan (1,6-anhydro-β-glucopyranose, C6H10O5), resin acids such as abietic acid (1-phenanthrenecarboxylic acid, C20H30O2), and lignin decomposition products such as 5-nitroguaiacol (2-methoxy-5-nitrophenol, C7H7NO4) have been exposed to a wide range of OH concentrations (~107-1011 cm-3), in presence of O2 in a rotating wall flow reactor operated at 2-6 mbar coupled to a custom built chemical ionization mass spectrometer (CIMS). OH radicals were generated through H2 dissociation in an Evenson microwave resonant cavity operated at 2.45 GHz followed by reaction with O2 or NO2. In addition, potential volatilization of organic material due to heterogeneous oxidation by OH has been determined in-situ by monitoring the volatile organic compounds using a high resolution-proton transfer reaction-time of flight-mass spectrometer (HR-PTR-ToF-MS). The volatilization studies are conducted at 1 atm and OH is generated by O3 photolysis in the presence of H2O vapor and quantified using a photochemical box model as well as through reaction with a known concentration of isoprene (2-methyl-1,3-butadiene, C5H8). Reactive uptake validation

  3. Toxic effect of volatile products of thermooxidizing decomposition of conveyor belts

    Energy Technology Data Exchange (ETDEWEB)

    Faff, J.; Dudkiewicz, J.; Kauczak, M.; Waniewski, E.; Tokarzewski, E.

    1985-01-01

    Toxic effects of thermo-oxidizing decomposition products of conveying belts made of PVC and rubber have been tested. The resultant smokes were passed through a protective absorber. During 14-days' post-exposure observation, an increased activity of asparagine, aminotransferase and in some animal alanine aminotransferase was found. Moderately increased pathomorphological changes were found in lungs (emphysema, oedema interstitial and bronchogenic inflammations), along with slight degenerative changes in the liver and kidneys. In the peripheral blood, increased amounts of erythrocytes and leukocytes were found.

  4. Functional Genomics Reveals That a Compact Terpene Synthase Gene Family Can Account for Terpene Volatile Production in Apple1[W

    Science.gov (United States)

    Nieuwenhuizen, Niels J.; Green, Sol A.; Chen, Xiuyin; Bailleul, Estelle J.D.; Matich, Adam J.; Wang, Mindy Y.; Atkinson, Ross G.

    2013-01-01

    Terpenes are specialized plant metabolites that act as attractants to pollinators and as defensive compounds against pathogens and herbivores, but they also play an important role in determining the quality of horticultural food products. We show that the genome of cultivated apple (Malus domestica) contains 55 putative terpene synthase (TPS) genes, of which only 10 are predicted to be functional. This low number of predicted functional TPS genes compared with other plant species was supported by the identification of only eight potentially functional TPS enzymes in apple ‘Royal Gala’ expressed sequence tag databases, including the previously characterized apple (E,E)-α-farnesene synthase. In planta functional characterization of these TPS enzymes showed that they could account for the majority of terpene volatiles produced in cv Royal Gala, including the sesquiterpenes germacrene-D and (E)-β-caryophyllene, the monoterpenes linalool and α-pinene, and the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene. Relative expression analysis of the TPS genes indicated that floral and vegetative tissues were the primary sites of terpene production in cv Royal Gala. However, production of cv Royal Gala floral-specific terpenes and TPS genes was observed in the fruit of some heritage apple cultivars. Our results suggest that the apple TPS gene family has been shaped by a combination of ancestral and more recent genome-wide duplication events. The relatively small number of functional enzymes suggests that the remaining terpenes produced in floral and vegetative and fruit tissues are maintained under a positive selective pressure, while the small number of terpenes found in the fruit of modern cultivars may be related to commercial breeding strategies. PMID:23256150

  5. Continuous determination of volatile products in anaerobic fermenters by on-line capillary gas chromatography

    International Nuclear Information System (INIS)

    Diamantis, V.; Melidis, P.; Aivasidis, A.

    2006-01-01

    Bio-ethanol and biogas produced during the anaerobic conversion of organic compounds has been a subject of great interest since the oil crisis of the 1970s. In ethanol fermentation and anaerobic treatment of wastewaters, end-product (ethanol) and intermediate-products (short-chain fatty acids, SCFA) cause inhibition that results in reduced process efficiency. Control of these constituents is of utmost importance for bioreactor optimization and process stability. Ethanol and SCFA can be detected with precision by capillary gas chromatography usually conducted in off-line measurements. In this work, an on-line monitoring and controlling system was developed and connected to the fermenter via an auto-sampling equipment, which could perform the feeding, filtration and dilution of the sample and final injection into the gas chromatograph through an automation-based programmed procedure. The sample was continuously pumped from the recycle stream of the bioreactor and treated using a microfiltration unit. The concentrate was returned to the reactor while the permeate was quantitatively mixed with an internal standard solution. The system comprised of a gas chromatograph with the flow cell and one-shot sampler and a PC with the appropriate software. The on-line measurement of ethanol and SCFA, directly from the liquid phase of an ethanol fermenter and a high-rate continuous mode anaerobic digester, was accomplished by gas chromatography. Also, this monitoring and controlling system was proved to be effective in the continuous fermentation of alcohol-free beer

  6. Mass production of bacterial communities adapted to the degradation of volatile organic compounds (TEX).

    Science.gov (United States)

    Lapertot, Miléna; Seignez, Chantal; Ebrahimi, Sirous; Delorme, Sandrine; Peringer, Paul

    2007-06-01

    This study focuses on the mass cultivation of bacteria adapted to the degradation of a mixture composed of toluene, ethylbenzene, o-, m- and p-xylenes (TEX). For the cultivation process Substrate Pulse Batch (SPB) technique was adapted under well-automated conditions. The key parameters to be monitored were handled by LabVIEW software including, temperature, pH, dissolved oxygen and turbidity. Other parameters, such as biomass, ammonium or residual substrate concentrations needed offline measurements. SPB technique has been successfully tested experimentally on TEX. The overall behavior of the mixed bacterial population was observed and discussed along the cultivation process. Carbon and nitrogen limitations were shown to affect the integrity of the bacterial cells as well as their production of exopolymeric substances (EPS). Average productivity and yield values successfully reached the industrial specifications, which were 0.45 kg(DW)m(-3) d(-1) and 0.59 g(DW)g (C) (-1) , respectively. Accuracy and reproducibility of the obtained results present the controlled SPB process as a feasible technique.

  7. Changes in volatile production during an infection of tomato plants by Botrytis cinerea

    NARCIS (Netherlands)

    Jansen, R.M.C.; Miebach, M.; Kleist, E.; Henten, van E.J.; Wildt, J.

    2006-01-01

    Botrytis blight caused by the fungus Botrytis cinerea is probably the most common disease of greenhouse-grown crops like tomato. Botrytis blight in tomato plants is mainly detected by visual inspection or destructive biochemical and molecular determinations. These methods are time consuming and not

  8. Inbreeding in horsenettle (Solanum carolinense) alters night-time volatile emissions that guide oviposition by Manduca sexta moths.

    Science.gov (United States)

    Kariyat, Rupesh R; Mauck, Kerry E; Balogh, Christopher M; Stephenson, Andrew G; Mescher, Mark C; De Moraes, Consuelo M

    2013-04-22

    Plant volatiles serve as key foraging and oviposition cues for insect herbivores as well as their natural enemies, but little is known about how genetic variation within plant populations influences volatile-mediated interactions among plants and insects. Here, we explore how inbred and outbred plants from three maternal families of the native weed horsenettle (Solanum carolinense) vary in the emission of volatile organic compounds during the dark phase of the photoperiod, and the effects of this variation on the oviposition preferences of Manduca sexta moths, whose larvae are specialist herbivores of Solanaceae. Compared with inbred plants, outbred plants consistently released more total volatiles at night and more individual compounds-including some previously reported to repel moths and attract predators. Female moths overwhelmingly chose to lay eggs on inbred (versus outbred) plants, and this preference persisted when olfactory cues were presented in the absence of visual and contact cues. These results are consistent with our previous findings that inbred plants recruit more herbivores and suffer greater herbivory under field conditions. Furthermore, they suggest that constitutive volatiles released during the dark portion of the photoperiod can convey accurate information about plant defence status (and/or other aspects of host plant quality) to foraging herbivores.

  9. Eugenol stimulates lactate accumulation yet inhibits volatile fatty acid production and eliminates coliform bacteria in cattle and swine waste.

    Science.gov (United States)

    Varel, V H; Miller, D L

    2004-01-01

    To determine how eugenol affects fermentation parameters and faecal coliforms in cattle and swine waste slurries stored anaerobically. Waste slurries (faeces:urine:water, 50:35:15) were blended with and without additives and aliquoted to triplicate 1-l flasks. Faecal coliforms were eliminated in cattle and swine waste slurries within 1 or 2 days with additions of eugenol at 10.05 mm (0.15%) and 16.75 mm (0.25%). At these concentrations volatile fatty acids (VFA) were reduced ca 70 and 50% in cattle and swine waste, respectively, over 6-8 weeks. Additionally, in cattle waste, eugenol stimulated the accumulation of lactate (>180 mm) when compared with thymol treatment (20 mm lactate). In swine waste, lactate accumulation did not occur without additives; eugenol and thymol stimulated lactate accumulation to concentrations of 22 and 32 mm, respectively. Eugenol added to cattle waste may be more beneficial than thymol because not only does it effectively control faecal coliforms and odour (VFA production), it also stimulates lactate accumulation. This in turn, causes the pH to drop more rapidly, further inhibiting microbial activity and nutrient emissions. Plant essential oils have the potential to solve some of the environmental problems associated with consolidated animal feeding operations. Thymol and eugenol reduce fermentative activity, thus, have the potential to reduce emissions of greenhouse gases and odour, and curtail transmission of pathogens in cattle and swine wastes.

  10. Fusarium oxysporum induces the production of proteins and volatile organic compounds by Trichoderma harzianum T-E5.

    Science.gov (United States)

    Zhang, Fengge; Yang, Xingming; Ran, Wei; Shen, Qirong

    2014-10-01

    Trichoderma species have been used widely as biocontrol agents for the suppression of soil-borne pathogens. However, some antagonistic mechanisms of Trichoderma are not well characterized. In this study, a series of laboratory experiments were designed to characterize the importance of mycoparasitism, exoenzymes, and volatile organic compounds (VOCs) by Trichoderma harzianum T-E5 for the control of Fusarium oxysporum f. sp. cucumerinum (FOC). We further tested whether these mechanisms were inducible and upregulated in presence of FOC. The results were as follows: T-E5 heavily parasitized FOC by coiling and twisting the entire mycelium of the pathogen in dual cultures. T-E5 growing medium conditioned with deactivated FOC (T2) showed more proteins and higher cell wall-degrading enzyme activities than T1, suggesting that FOC could induce the upregulation of exoenzymes. The presence of deactivated FOC (T2') also resulted in the upregulation of VOCs that five and eight different types T-E5-derived VOCs were identified from T1' and T2', respectively. Further, the excreted VOCs in T2' showed significantly higher antifungal activities against FOC than T1'. In conclusion, mycoparasitism of T-E5 against FOC involved mycelium contact and the production of complex extracellular substances. Together, these data provide clues to help further clarify the interactions between these fungi. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  11. Volatile elements production rates in a 1.4 Gev proton-irradiated molten lead-bismuth target

    CERN Document Server

    Zanini, L; Everaerts, P; Fallot, M; Franberg, H; Gröschel, F; Jost, C; Kirchner, T; Kojima, Y; Köster, U; Lebenhaft, J; Manfrina, E; Pitcher, E J; Ravn, H L; Tall, Y; Wagner, W; Wohlmuther, M

    2005-01-01

    Production rates of volatile elements following spallation reaction of 1.4 GeV protons on a liquid Pb/Bi target have been measured. The experiment was performed at the ISOLDE facility at CERN. These data are of interest for the developments of targets for accelerator driven systems such as MEGAPIE. Additional data have been taken on a liquid Pb target. Calculations were performed using the FLUKA and MCNPX Monte Carlo codes coupled with the evolution codes ORIHET3 and FISPACT using different options for the intra-nuclear cascades and evaporation models. Preliminary results from the data analysis show good comparison with calculations for Hg and for noble gases. For other elements such as I it is apparent that only a fraction of the produced isotopes is released. The agreement with the experimental data varies depending on the model combination used. The best results are obtained using MCNPX with the INCL4/ABLA models and with FLUKA. Discrepancies are found for some isotopes produced by fission using the MCNPX ...

  12. Modelling the release of volatile fission product cesium from CANDU fuel under severe accident conditions using artificial neural networks

    International Nuclear Information System (INIS)

    Andrews, W.S.; Lewis, B.J.; Cox, D.S.

    1997-01-01

    An artificial neural network (ANN) model has been developed to predict the release of volatile fission products from CANDU fuel under severe accident conditions. The model was based on data for the release Of 134 Cs measured during three annealing experiments (Hot Cell Experiments 1 and 2, or HCE- 1, HCE-2 and Metallurgical Cell Experiment 1, or MCE- 1) at Chalk River Laboratories. These experiments were comprised of a total of 30 separate tests. The ANN established a correlation among 14 separate input variables and predicted the cumulative fractional release for a set of 386 data points drawn from 29 tests to a normalized error, E n , of 0.104 and an average absolute error, E abs , of 0.064. Predictions for a blind validation set (test HCE2-CM6) had an E n of 0.064 and an E abs of 0.054. A methodology is presented for deploying the ANN model by providing the connection weights. Finally, the performance of an ANN model was compared to a fuel oxidation model developed by Lewis et al. and to the U.S. Nuclear Regulatory Commission's CORSOR-M. (author)

  13. Prevention of volatile fatty acids production and limitation of odours from winery wastewaters by denitrification.

    Science.gov (United States)

    Bories, André; Guillot, Jean-Michel; Sire, Yannick; Couderc, Marie; Lemaire, Sophie-Andréa; Kreim, Virginie; Roux, Jean-Claude

    2007-07-01

    The effect of the addition of nitrate to winery wastewaters to control the formation of VFA in order to prevent odours during storage and treatment was studied in batch bioreactors at different NO(3)/chemical oxygen demand (COD) ratios and at full scale in natural evaporation ponds (2 x 7000 m(2)) by measuring olfactory intensity. In the absence of nitrate, butyric acid (2304 mgL(-1)), acetic acid (1633 mgL(-1)), propionic acid (1558 mgL(-1)), caproic acid (499 mgL(-1)) and valeric acid (298 mgL(-1)) were produced from reconstituted winery wastewater. For a ratio of NO(3)/COD=0.4 gg(-1), caproic and valeric acids were not formed. The production of butyric and propionic acids was reduced by 93.3% and 72.5%, respectively, at a ratio of NO(3)/COD=0.8, and by 97.4% and 100% at a ratio of NO(3)/COD=1.2 gg(-1). Nitrate delayed and decreased butyric acid formation in relation to the oxidoreduction potential. Studies in ponds showed that the addition of concentrated calcium nitrate (NITCAL) to winery wastewaters (3526 m(3)) in a ratio of NO(3)/COD=0.8 inhibited VFA production, with COD elimination (94%) and total nitrate degradation, and no final nitrite accumulation. On the contrary, in ponds not treated with nitrate, malodorous VFA (from propionic to heptanoïc acids) represented up to 60% of the COD. Olfactory intensity measurements in relation to the butanol scale of VFA solutions and the ponds revealed the pervasive role of VFA in the odour of the untreated pond as well as the clear decrease in the intensity and not unpleasant odour of the winery wastewater pond enriched in nitrates. The results obtained at full scale underscored the feasibility and safety of the calcium nitrate treatment as opposed to concentrated nitric acid.

  14. Evaluation of potential for mercury volatilization from natural and FGD gypsum products using flux-chamber tests.

    Science.gov (United States)

    Shock, Scott S; Noggle, Jessica J; Bloom, Nicholas; Yost, Lisa J

    2009-04-01

    Synthetic gypsum produced by flue-gas desulfurization (FGD) in coal-fired power plants (FGD gypsum) is put to productive use in manufacturing wallboard. FGD gypsum wallboard is widely used, accounting for nearly 30% of wallboard sold in the United States. Mercury is captured in flue gas and thus is one of the trace metals present in FGD gypsum; raising questions about the potential for mercury exposure from wallboard. Mercury is also one of the trace metals present in "natural" mined gypsum used to make wall board. Data available in the literature were not adequate to assess whether mercury in wallboard from either FGD or natural gypsum could volatilize into indoor air. In this study, mercury volatilization was evaluated using small-scale (5 L) glass and Teflon flux chambers, with samples collected using both iodated carbon and gold-coated sand traps. Mercury flux measurements made using iodated carbon traps (n=6) were below the detection limit of 11.5 ng/m2-day for all natural and synthetic gypsum wallboard samples. Mercury flux measurements made using gold-coated sand traps (n=6) were 0.92 +/- 0.11 ng/m2-day for natural gypsum wallboard and 5.9 +/- 2.4 ng/m2-day for synthetic gypsum wallboard. Room air mercury concentrations between 0.028 and 0.28 ng/m3 and between 0.13 and 2.2 ng/m3 were estimated based on the flux-rate data for natural and synthetic gypsum wallboard samples, respectively, and were calculated assuming a 3 m x 4 m x 5 m room, and 10th and 90th percentile air exchange rates of 0.18/hour and 1.26/hour. The resulting concentration estimates are well below the U.S. Environmental Protection Agency (EPA) reference concentration for indoor air elemental mercury of 300 ng/m3 and the Agency for Toxic Substances and Disease Registry minimal risk level (MRL) of 200 ng/m3. Further, these estimates are below background mercury concentrations in indoor air and within or below the range of typical background mercury concentrations in outdoor air.

  15. Papers of the 2. annual Canadian Institute conference on managing natural gas price volatility : effective risk strategies for turbulent times

    International Nuclear Information System (INIS)

    2002-01-01

    The issue of how natural gas price volatility is affecting future energy projects was the focus of this conference. Discussions focused on the dynamics of supply and demand of natural gas in North America and how end-users are responding to price fluctuations. Methods by which storage can be used as an effective risk management tool was also on the agenda. The hedging strategies that work best for leading energy firms were described. It was noted that price volatility can be reduced through improved market transparency. Discussions also focused on credit risk in a volatile price environment. A total of 17 papers were presented of which 3 were indexed separately for inclusion in the database. tabs., figs

  16. 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...

  17. Real-time monitoring of respiratory absorption factors of volatile organic compounds in ambient air by proton transfer reaction time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhonghui [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yanli [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Yan, Qiong [Department of Respiratory Diseases, Guangzhou No. 12 People' s Hospital, Guangzhou 510620 (China); Zhang, Zhou [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wang, Xinming, E-mail: wangxm@gig.ac.cn [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China)

    2016-12-15

    Respiratory absorption factors (AFs) are essential parameters in the evaluation of human health risks from toxic volatile organic compounds (VOCs) in ambient air. A method for the real time monitoring of VOCs in inhaled and exhaled air by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) has been developed to permit the calculation of respiratory AFs of VOCs. Isoprene was found to be a better breath tracer than O{sub 2}, CO{sub 2}, humidity, or acetone for distinguishing between the expiratory and inspiratory phases, and a homemade online breath sampling device with a buffer tube was used to optimize signal peak shapes. Preliminary tests with seven subjects exposed to aromatic hydrocarbons in an indoor environment revealed mean respiratory AFs of 55.0%, 55.9%, and 66.9% for benzene, toluene, and C8-aromatics (ethylbenzene and xylenes), respectively. These AFs were lower than the values of 90% or 100% used in previous studies when assessing the health risks of inhalation exposure to hazardous VOCs. The mean respiratory AFs of benzene, toluene and C8-aromatics were 66.5%, 70.2% and 82.3% for the three female subjects; they were noticeably much higher than that of 46.4%, 45.2% and 55.3%, respectively, for the four male subjects.

  18. Concentrations of cyclic volatile methylsiloxanes in European cosmetics and personal care products: Prerequisite for human and environmental exposure assessment

    NARCIS (Netherlands)

    Dudzina, T.; Goetz, N. von; Bogdal, C.; Biesterbos, J.W.H.; Hungerbuhler, K.

    2014-01-01

    Low molecular weight cyclic volatile methylsiloxanes (cVMSs) are widely employed as emollients and carrier solvents in personal care formulations in order to acquire desired performance benefits owing to their distinctive physicochemical properties. Under current European legislation cosmetic

  19. 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.

  20. 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.

  1. [Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].

    Science.gov (United States)

    Cui, Ru; Ma, Yong-Liang

    2013-12-01

    Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point.

  2. 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....

  3. Plant essential oils and allied volatile fractions as multifunctional additives in meat and fish-based food products: a review.

    Science.gov (United States)

    Patel, Seema

    2015-01-01

    Essential oils are concentrated aromatic volatile compounds derived from botanicals by distillation or mechanical pressing. They play multiple, crucial roles as antioxidants, food pathogen inhibitors, shelf-life enhancers, texture promoters, organoleptic agents and toxicity-reducing agents. For their versatility, they appear promising as food preservatives. Several research findings in recent times have validated their potential as functional ingredients in meat and fish processing. Among the assortment of bioactive compounds in the essential oils, p-cymene, thymol, eugenol, carvacrol, isothiocyanate, cinnamaldehyde, cuminaldehyde, linalool, 1,8-cineol, α-pinene, α-terpineol, γ-terpinene, citral and methyl chavicol are most familiar. These terpenes (monoterpenes and sesquiterpenes) and phenolics (alcohols, esters, aldehydes and ketones) have been extracted from culinary herbs such as oregano, rosemary, basil, coriander, cumin, cinnamon, mint, sage and lavender as well as from trees such as myrtle, fir and eucalyptus. This review presents essential oils as alternatives to conventional chemical additives. Their synergistic actions with modified air packaging, irradiation, edible films, bacteriocins and plant byproducts are discussed. The decisive roles of metabolic engineering, microwave technology and metabolomics in quality and quantity augmentation of essential oil are briefly mooted. The limitations encountered and strategies to overcome them have been illuminated to pave way for their enhanced popularisation. The literature has been mined from scientific databases such as Pubmed, Pubchem, Scopus and SciFinder.

  4. Production of volatile fatty acid in the rumen and its relationship with their concentration, intake of dry matter and digestible organic matter in buffalo (Bos bubalis) calves

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.

    1979-01-01

    The production rates of total volatile fatty acid (TVFA) in the rumen of buffalo (Bos bubalis) calves were estimated using a single injection isotope dilution technique. A series of twelve experiments were done with animals given wheat straw and concentrate mixture. The production rate of TVFA ranged from 19.77 to 24.84 moles/d depending upon the amount of food consumed by the animals. Highly significant correlations were observed between TVFA production and their concentration, dry matter and digestible organic matter intake. (auth.)

  5. In cleanroom, sub-ppb real-time monitoring of volatile organic compounds using proton-transfer reaction/time of flight/mass spectrometry

    Science.gov (United States)

    Hayeck, Nathalie; Maillot, Philippe; Vitrani, Thomas; Pic, Nicolas; Wortham, Henri; Gligorovski, Sasho; Temime-Roussel, Brice; Mizzi, Aurélie; Poulet, Irène

    2014-04-01

    Refractory compounds such as Trimethylsilanol (TMS) and other organic compounds such as propylene glycol methyl ether acetate (PGMEA) used in the photolithography area of microelectronic cleanrooms have irreversible dramatic impact on optical lenses used on photolithography tools. There is a need for real-time, continuous measurements of organic contaminants in representative cleanroom environment especially in lithography zone. Such information is essential to properly evaluate the impact of organic contamination on optical lenses. In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was applied for real-time and continuous monitoring of fugitive organic contamination induced by the fabrication process. Three types of measurements were carried out using the PTR-TOF-MS in order to detect the volatile organic compounds (VOCs) next to the tools in the photolithography area and at the upstream and downstream of chemical filters used to purge the air in the cleanroom environment. A validation and verification of the results obtained with PTR-TOF-MS was performed by comparing these results with those obtained with an off-line technique that is Automated Thermal Desorber - Gas Chromatography - Mass Spectrometry (ATD-GC-MS) used as a reference analytical method. The emerged results from the PTR-TOF-MS analysis exhibited the temporal variation of the VOCs levels in the cleanroom environment during the fabrication process. While comparing the results emerging from the two techniques, a good agreement was found between the results obtained with PTR-TOF-MS and those obtained with ATD-GC-MS for the PGMEA, toluene and xylene. Regarding TMS, a significant difference was observed ascribed to the technical performance of both instruments.

  6. Fermentative activity and production of volatile compounds by Saccharomyces grown in synthetic grape juice media deficient in assimilable nitrogen and/or pantothenic acid.

    Science.gov (United States)

    Wang, X D; Bohlscheid, J C; Edwards, C G

    2003-01-01

    To understand the impact of assimilable nitrogen and pantothenic acid on fermentation rate and synthesis of volatile compounds by Saccharomyces under fermentative conditions. A 2 x 3 factorial experimental design was employed with the concentrations of yeast assimilable nitrogen (YAN) (60 and 250 mg l(-1)) and pantothenic acid (10, 50 and 250 microg l(-1)) as variables. In media containing 250 microg l(-1) pantothenic acid, H2S production by two different species of Saccharomyces decreased when YAN was increased from 60 to 250 mg l(-1). Conversely, H2S production was significantly higher when the concentration of assimilable nitrogen was increased if pantothenic acid was deficient (10 or 50 microg l(-1)). Yeast synthesis of other volatile compounds were impacted by both assimilable nitrogen and pantothenic acid. While growth and fermentative rate of Saccharomyces was more influenced by nitrogen than by pantothenic acid, complicated interactions exist between these nutrients that affect the synthesis of volatile compounds including H2S. This study has important implications for the winemaking industry where a better understanding of the nutritional requirements of Saccharomyces is necessary to reduce fermentation problems and to improve final product quality.

  7. Potential of select intermediate-volatility organic compounds and consumer products for secondary organic aerosol and ozone formation under relevant urban conditions

    Science.gov (United States)

    Li, Weihua; Li, Lijie; Chen, Chia-li; Kacarab, Mary; Peng, Weihan; Price, Derek; Xu, Jin; Cocker, David R.

    2018-04-01

    Emissions of certain low vapor pressure-volatile organic compounds (LVP-VOCs) are considered exempt to volatile organic compounds (VOC) regulations due to their low evaporation rates. However, these compounds may still play a role in ambient secondary organic aerosol (SOA) and ozone formation. The LVP-VOCs selected for this work are categorized as intermediate-volatility organic compounds (IVOCs) according to their vapor pressures and molecular formulas. In this study, the evaporation rates of 14 select IVOCs are investigated with half of them losing more than 95% of their mass in less than one month. Further, SOA and ozone formation are presented from 11 select IVOCs and 5 IVOC-containing generic consumer products under atmospherically relevant conditions using varying radical sources (NOx and/or H2O2) and a surrogate reactive organic gas (ROG) mixture. Benzyl alcohol (0.41), n-heptadecane (0.38), and diethylene glycol monobutyl ether (0.16) are determined to have SOA yields greater than 0.1 in the presence of NOx and a surrogate urban hydrocarbon mixture. IVOCs also influence ozone formation from the surrogate urban mixture by impacting radical levels and NOx availability. The addition of lab created generic consumer products has a weak influence on ozone formation from the surrogate mixture but strongly affects SOA formation. The overall SOA and ozone formation of the generic consumer products could not be explained solely by the results of the pure IVOC experiments.

  8. 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

  9. 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

  10. Improving productivity through more effective time management.

    Science.gov (United States)

    Arnold, Edwin; Pulich, Marcia

    2004-01-01

    Effective time management has become increasingly important for managers as they seek to accomplish objectives in today's organizations, which have been restructured for efficiency while employing fewer people. Managers can improve their ability to manage time effectively by examining their attitudes toward time, analyzing time-wasting behaviors, and developing better time management skills. Managers can improve their performance and promotion potential with more effective time utilization. Strategies for improving time management skills are presented.

  11. Simultaneous determination of volatile and non-volatile nitrosamines in processed meat products by liquid chromatography tandem mass spectrometry using atmospheric pressure chemical ionisation and electrospray ionisation

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Duedahl-Olesen, Lene; Granby, Kit

    2014-01-01

    , it was only possible to ionize N-nitroso-thiazolidine-4-carboxylic acid (NTCA) and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA) by ESI. The validated method was applied for the analysis of processed meat products and contents of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N...

  12. 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.

  13. 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...

  14. Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres

    Science.gov (United States)

    Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.

    2015-05-01

    Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study

  15. Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain

    DEFF Research Database (Denmark)

    Bak, Kathrine Holmgaard; Petersen, Mikael Agerlin; Lametsch, Rene

    2018-01-01

    of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found...

  16. Release of hydroxycinnamic acids and formation of flavour-active volatile phenols during the beer production process

    OpenAIRE

    Vanbeneden, Nele

    2007-01-01

    Among the flavour-active volatile phenols in beer, most of them originate from the raw materials used in the brewing process. Only some of them can be formed by yeast activity, namely 4-vinylguaiacol (4VG) and 4-vinylphenol (4VP). The presence of these volatile phenolic compounds is considered undesirable when present in excessive concentration in bottom-fermented pilsner beers, hence the term “phenolic off-flavour” (POF). It is attributed to beers with a strong medicinal, clove-like aroma. D...

  17. 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...

  18. Comparison of cultivars of ornamental crop Gerbera jamesonii on production of spider mite-induced volatiles, and their attractiveness to the predator Phytoseiulus persimilis.

    Science.gov (United States)

    Krips, O E; Willems, P E; Gols, R; Posthumus, M A; Gort, G; Dicke, M

    2001-07-01

    We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase (rm). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P persimilis. Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis. Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis-alpha-bergamotene, trans-alpha-bergamotene, trans-beta-bergamotene, and (E)-beta-farnesene. The emission of (E)-beta-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.

  19. Influence of dispatching rules on average production lead time for multi-stage production systems.

    Science.gov (United States)

    Hübl, Alexander; Jodlbauer, Herbert; Altendorfer, Klaus

    2013-08-01

    In this paper the influence of different dispatching rules on the average production lead time is investigated. Two theorems based on covariance between processing time and production lead time are formulated and proved theoretically. Theorem 1 links the average production lead time to the "processing time weighted production lead time" for the multi-stage production systems analytically. The influence of different dispatching rules on average lead time, which is well known from simulation and empirical studies, can be proved theoretically in Theorem 2 for a single stage production system. A simulation study is conducted to gain more insight into the influence of dispatching rules on average production lead time in a multi-stage production system. We find that the "processing time weighted average production lead time" for a multi-stage production system is not invariant of the applied dispatching rule and can be used as a dispatching rule independent indicator for single-stage production systems.

  20. Isolation and identification of volatile kairomone that affects acarine predator-prey interactions: involvement of host plant in its production.

    NARCIS (Netherlands)

    Dicke, M.; Beek, van T.A.; Posthumus, M.A.; Dom, Ben N.; Bokhoven, van H.; Groot, de Ae.

    1990-01-01

    A volatile kairomone emitted from lima bean plants (Phaseolus lunatus) infested with the spider miteTetranychus urticae, was collected on Tenax-TA and analyzed with GC-MS. Two components were identified as the methylene monoterpene (3E)-4,8-dimethyl-1,3,7-nonatriene and the methylene sesquiterpene

  1. Effect of ozonation of swimming pool water on formation of volatile disinfection by-products - A laboratory study

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Spiliotopoulou, Aikaterini; Cheema, Waqas Akram

    2016-01-01

    Ozonation experiments were performed using unchlorinated tap water used for filling municipal swimming pools, actual pool water and pool water polluted by addition of fresh tap water and artificial body fluid to evaluate ozone kinetics and water quality effects on formation of volatile disinfecti...

  2. Characterization of Chemical Composition of Pericarpium Citri Reticulatae Volatile Oil by Comprehensive Two-Dimensional Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kunming Qin

    2013-01-01

    Full Text Available Pericarpium Citri Reticulatae (Chenpi in Chinese has been widely used as an herbal medicine in Korea, China, and Japan. Chenpi extracts are used to treat indigestion and inflammatory syndromes of the respiratory tract such as bronchitis and asthma. This thesis will analyze chemical compositions of Chenpi volatile oil, which was performed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC × GC-HR-TOFMS. One hundred and sixty-seven components were tentatively identified, and terpene compounds are the main components of Chenpi volatile oil, a significant larger number than in previous studies. The majority of the eluted compounds, which were identified, were well separated as a result of high-resolution capability of the GC × GC method, which significantly reduces, the coelution. β-Elemene is tentatively qualified by means of GC × GC in tandem with high-resolution TOFMS detection, which plays an important role in enhancing the effects of many anticancer drugs and in reducing the side effects of chemotherapy. This study suggests that GC × GC-HR-TOFMS is suitable for routine characterization of chemical composition of volatile oil in herbal medicines.

  3. Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production.

    Science.gov (United States)

    López-Alvarez, Arnoldo; Díaz-Pérez, Alma Laura; Sosa-Aguirre, Carlos; Macías-Rodríguez, Lourdes; Campos-García, Jesús

    2012-05-01

    In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Influence of the salting time on volatile compounds during the manufacture of dry-cured pork shoulder "lacón".

    Science.gov (United States)

    Purriños, Laura; Franco, Daniel; Carballo, Javier; Lorenzo, José M

    2012-12-01

    The effect of the length of salting time on volatile compounds throughout the manufacture of dry-cured "lacón" was studied using a purge-and-trap extraction and GC/MS analysis. For this study, six treatments of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)). The total area of volatile compounds increased significantly (Psalting time increased. Significant differences were found for the total area of all aldehydes for each salting time at the end of process. Hexanal presented the most relative abundance, showing highest content in HS treatments while LS treatments showed the lowest one at the end of salting, post-salting and drying-ripening stage. The influence of salting time on the content of 3-Octen-2-one was significant on salting stage (Psalting time affected (Psalting and at the end of drying-ripening stage. The salting time affected significantly (Psalt level (P>0.05) was detected on total hydrocarbons and total furans at the end of process. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. A plan to reduce volatile organic compound emissions from consumer products in Canada (excluding windshield washer fluid and surface coatings) : final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    This report highlights the recommendations made by the Canadian Council of Ministers of the Environment for the development of a guideline to provide a means by which to reduce (VOC) emissions from consumer products (excluding windshield washer fluid and surface coatings) in Canada. VOCs and nitrogen oxides react photochemically in the presence of sunlight to create ground-level ozone, a primary component of urban smog which has a detrimental effect on human health, agricultural crops and building materials. In recent years, most urban areas of Canada have shown an annual increase in the maximum acceptable air quality levels for ground level ozone. Reducing emissions of volatile organic compounds (VOCs) from consumer products was first suggested in 1990 by the Canadian Council of Ministers of the Environment in phase one of their program entitled the 'Management plan for nitrogen oxides and volatile organic compounds'. Phase 2 of the program was implemented in 1997 to harmonize the emissions reduction program with the United States Environmental Protection Agency regulations. The Canadian Environmental Protection Agency (CEPA) recommended the following control options: (1) a CEPA guideline should be developed which states the maximum VOC and high-volatility organic compound (HVOC) content in Canadian consumer products including hair care products, herbicides, insecticides, air fresheners, deodorants, fungicides, surface cleaners, fragrance products, anti-microbial agents, laundry products and automotive detailing products. These limits should be identical to those found in the 1998 U.S. Final Rule for Consumer Products, (2) the CEPA guideline should require that records specifying VOC content in weight-per cent be maintained for a period of three years, (3) the CEPA guideline should include a declaration procedure for Canadian importers and manufacturers of consumer products to report to Environment Canada regarding the VOC content of their products, and

  6. Production Planning with Load Dependent Lead Times

    DEFF Research Database (Denmark)

    Pahl, Julia

    2005-01-01

    Lead times impact the performance of the supply chain significantly. Although there is a large literature concerning queuing models for the analysis of the relationship between capacity utilization and lead times, and there is a substantial literature concerning control and order release policies...... that take lead times into consideration, there have been only few papers describing models at the aggregate planning level that recognize the relationship between the planned utilization of capacity and lead times. In this paper we provide an in-depth discussion of the state-of-the art in this literature......, with particular attention to those models that are appropriate at the aggregate planning level....

  7. EFFECTIVE SAVINGS IN PRODUCTION TIMES AND COST

    African Journals Online (AJOL)

    ES OBE

    lamination process itself [5,6,7]. The purpose of this work is to fully expose, by means of experimental data, the ... takes staff to laminate such work piece (in cases of handlay-up processes) and machines. (for resin injection .... The unfinished layer of mat being laminated usually result in laminate products with rough surfaces ...

  8. Volatility and entrainment of feed components and product glass characteristics during pilot-scale vitrification of simulated Hanford site low-level waste

    International Nuclear Information System (INIS)

    Shade, J.W.

    1996-01-01

    Commercially available melter technologies were tested for application to vitrification of Hanford site low-level waste (LLW). Testing was conducted at vendor facilities using a non-radioactive LLW simulant. Technologies tested included four Joule-heated melter types, a carbon electrode melter, a cyclone combustion melter, and a plasma torch-fired melter. A variety of samples were collected during the vendor tests and analyzed to provide data to support evaluation of the technologies. This paper describes the evaluation of melter feed component volatility and entrainment losses and product glass samples produced during the vendor tests. All vendors produced glasses that met minimum leach criteria established for the test glass formulations, although in many cases the waste oxide loading was less than intended. Entrainment was much lower in Joule-heated systems than in the combustion or plasma torch-fired systems. Volatility of alkali metals, halogens, B, Mo, and P were severe for non-Joule-heated systems. While losses of sulfur were significant for all systems, the volatility of other components was greatly reduced for some configurations of Joule-heated melters. Data on approaches to reduce NO x generation, resulting from high nitrate and nitrite content in the double-shell slurry feed, are also presented

  9. Drought-tolerance of wheat improved by rhizosphere bacteria from harsh environments: enhanced biomass production and reduced emissions of stress volatiles.

    Directory of Open Access Journals (Sweden)

    Salme Timmusk

    Full Text Available Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates.

  10. Emission and profile characteristic of volatile organic compounds emitted from coke production, iron smelt, heating station and power plant in Liaoning Province, China.

    Science.gov (United States)

    Shi, Jianwu; Deng, Hao; Bai, Zhipeng; Kong, Shaofei; Wang, Xiuyan; Hao, Jiming; Han, Xinyu; Ning, Ping

    2015-05-15

    107 kinds of C₂-C₁₂ volatile organic compound (VOC) mass concentrations and profiles for four types of coal-fired stationary sources in Liaoning Province were studied by a dilution sampling system and GC-MS analysis method, which are of significant importance with regard to VOC emissions in northeast of China. The results showed that there were some differences among these VOC source profiles. The total mass concentrations of analyzed 107 VOC species varied from 10,917 to 19,652 μg m(-3). Halogenated hydrocarbons exhibited higher mass percentages for the VOC source profiles of iron smelt (48.8%) and coke production plant (37.7%). Aromatic hydrocarbons were the most abundant in heating station plant (69.1%). Ketones, alcohols and acetates held 45.0% of total VOCs in thermal power plant. For non-methane hydrocarbons (NMHCs), which are demanded for photochemical assessment in the USA, toluene and n-hexane were the most abundant species in the iron smelt, coke production and thermal power plant, with the mass percentages of 64.8%, 52.7% and 38.6%, respectively. Trimethylbenzene, n-propylbenzene and o,m-ethyltoluene approximately accounted for 70.0% in heating station plant. NMHCs emitted from coke production, iron smelt, heating station and power plant listed above presented different chemical reactivities. The average OH loss rate of NMHCs from heating station, was 4 to 5.6 times higher than that of NMHCs from iron smelt, coke production and power plant, which implies that VOCs emitted from heating station in northeast of China should be controlled firstly to avoid photochemical ozone pollution and protect human health. There are significant variations in the ratios of benzene/toluene and m, p-xylene/ethylbenzene of these coal-fired source profiles. The representativeness of the coal-fired sources studied and the VOC samples collected should be more closely examined. The accuracy of VOC source profiles related to coal-fired processes is highly dependent on

  11. Real-Time Tropospheric Product Establishment and Accuracy Assessment in China

    Science.gov (United States)

    Chen, M.; Guo, J.; Wu, J.; Song, W.; Zhang, D.

    2018-04-01

    Tropospheric delay has always been an important issue in Global Navigation Satellite System (GNSS) processing. Empirical tropospheric delay models are difficult to simulate complex and volatile atmospheric environments, resulting in poor accuracy of the empirical model and difficulty in meeting precise positioning demand. In recent years, some scholars proposed to establish real-time tropospheric product by using real-time or near-real-time GNSS observations in a small region, and achieved some good results. This paper uses real-time observing data of 210 Chinese national GNSS reference stations to estimate the tropospheric delay, and establishes ZWD grid model in the country wide. In order to analyze the influence of tropospheric grid product on wide-area real-time PPP, this paper compares the method of taking ZWD grid product as a constraint with the model correction method. The results show that the ZWD grid product estimated based on the national reference stations can improve PPP accuracy and convergence speed. The accuracy in the north (N), east (E) and up (U) direction increase by 31.8 %,15.6 % and 38.3 %, respectively. As with the convergence speed, the accuracy of U direction experiences the most improvement.

  12. Modeling the sensory impact of defined combinations of volatile lipid oxidation products on fishy and metallic off-flavors

    DEFF Research Database (Denmark)

    Venkateshwarlu Venkat, Guidipati; Bruni Let, Mette; Meyer, Anne S.

    2004-01-01

    and highlighted the importance of two-factor interactions for contribution toward off-flavors. The results suggest that (EZ)-2,6-nonadienal and 1-penten-3-one could be useful markers for fishy and metallic off-flavors in fish oil and fish oil enriched foods. Within the addition levels of the volatiles...... volatiles were subjected to sensory descriptive analysis for fishy and metallic off-flavors. The data were analyzed using partial least-squares regression and multiple linear regression to develop mathematical models. The models revealed significant main effects of (EZ)-2,6-nonadienal and 1-penten-3-one...... there was a curvature effect of (EZ)-2,6-nonadienal, a compensatory effect of (Z)-4-heptenal and (EE)-2,4-heptadienal, and a synergistic effect of (EZ)-2,6-nonadienal and (Z)-4-heptenal in the development of fishy off-flavors...

  13. 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...

  14. Detecting Chaos from Agricultural Product Price Time Series

    Directory of Open Access Journals (Sweden)

    Xin Su

    2014-12-01

    Full Text Available Analysis of the characteristics of agricultural product price volatility and trend forecasting are necessary to formulate and implement agricultural price control policies. Taking wholesale cabbage prices as an example, a multiple test methodology has been adopted to identify the nonlinearity, fractality, and chaos of the data. The approaches used include the R/S analysis, the BDS test, the power spectra, the recurrence plot, the largest Lyapunov exponent, the Kolmogorov entropy, and the correlation dimension. The results show that there is chaos in agricultural wholesale price data, which provides a good theoretical basis for selecting reasonable forecasting models as prediction techniques based on chaos theory can be applied to forecasting agricultural prices.

  15. Quality & timely delivery of products and services

    Energy Technology Data Exchange (ETDEWEB)

    Scott, K.; Shabbir, K. [WorleyParsons, Toronto, ON (Canada)

    2015-07-01

    This paper discusses quality and timely delivery of services. The approach is to support our customers, to ensure quality, schedule and cost predictability with no compromise to safety, to avoid optimistic project schedules and conservative cost estimates. It is important to maintain a strategic focus in helping to improve the customer's assets and improve the methodology to improve assets.

  16. Quality & timely delivery of products and services

    International Nuclear Information System (INIS)

    Scott, K.; Shabbir, K.

    2015-01-01

    This paper discusses quality and timely delivery of services. The approach is to support our customers, to ensure quality, schedule and cost predictability with no compromise to safety, to avoid optimistic project schedules and conservative cost estimates. It is important to maintain a strategic focus in helping to improve the customer's assets and improve the methodology to improve assets.

  17. 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...

  18. TIME MANAGEMENT - AN INSTRUMENT TO IMPROVE PRODUCTIVITY

    Directory of Open Access Journals (Sweden)

    Johan Nortje

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: TIME is an Important element in any persons life as a plannlng mechanlsm to meaningfully organIse activities, or to ensure that a oroject runs WIth but also as a generator of destructive forces over it is lost. In the process of growth and progress ln a dynamIC everchanging envIronment. tIme not only becomes dearer to management, but also $carcet-, and an era of "time poverty" is experienced by many. A varIety of uncontrollable factors may be the cause of such problems, but a danger eXIsts that those factors over which control may be exercised could be lost within the uncontrol labie ones. The objective of this artIcle on tIme management is then to assist in identIfying those "barriers" which lead to "time pover'ty", how to avoid and prevent tIme wastage and apply methods, and make use of ways to promote the effective use of tIme.

    AFRIKAANSE OPSOMMING: TYD is 'n belangrlke faktor In dIe lewe van dIe mens enersyds dlen dlt as 'n beplannlngsmeganlsme am jOU daaglikse aktiwitelte slnvol te orden of am 'n pro.lek met preS1Sle te laat verloop, maar andersvds kan dlt ook vernietigende kragte genereer lndlen 'n mens daaroor beheer verloor. In die proses van groel en voorultgang In 'n dinamles veranderende omgewlng, raak dIe tyd van bestuur nle aIleen kosbaarder n ie, maarook skaar'ser en 'n era van' tydarmoede' word deur ba i e ervaar·. ' n Verskel denhe 1d van onbehee rbare faktore mag hiervoor verantwoordeilk wees, maar dIe gevaar bestaan dat die mens dle greep op dIe beheerbare faktore mag verloor. Die DOEL met hierdle artlkel oor tydsbestuur IS jU1S om behulpsaam te wees met dIe ldentiflsering van "slaggate" wat tot'tydat-moede" aanlelding gee. hoe am tydverkwlstlng te voorkom of te hanteer en die toepassing van metodes en gebruik van hulpmiddels om effektiewe tydsbestuur te bevorder.

  19. Aqueous-phase oxidation of green leaf volatiles by hydroxyl radical as a source of SOA: Product identification from methyl jasmonate and methyl salicylate oxidation

    Science.gov (United States)

    Hansel, Amie K.; Ehrenhauser, Franz S.; Richards-Henderson, Nicole K.; Anastasio, Cort; Valsaraj, Kalliat T.

    2015-02-01

    Green leaf volatiles (GLVs) are a group of biogenic volatile organic compounds (BVOCs) released into the atmosphere by vegetation. BVOCs produce secondary organic aerosol (SOA) via gas-phase reactions, but little is known of their aqueous-phase oxidation as a source of SOA. GLVs can partition into atmospheric water phases, e.g., fog, mist, dew or rain, and be oxidized by hydroxyl radicals (˙OH). These reactions in the liquid phase also lead to products that have higher molecular weights, increased polarity, and lower vapor pressures, ultimately forming SOA after evaporation of the droplet. To examine this process, we investigated the aqueous, ˙OH-mediated oxidation of methyl jasmonate (MeJa) and methyl salicylate (MeSa), two GLVs that produce aqueous-phase SOA. High performance liquid chromatography/electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to monitor product formation. The oxidation products identified exhibit higher molecular mass than their parent GLV due to either dimerization or the addition of oxygen and hydroxyl functional groups. The proposed structures of potential products are based on mechanistic considerations combined with the HPLC/ESI-MS data. Based on the structures, the vapor pressure and the Henry's law constant were estimated with multiple methods (SPARC, SIMPOL, MPBPVP, Bond and Group Estimations). The estimated vapor pressures of the products identified are significantly (up to 7 orders of magnitude) lower than those of the associated parent compounds, and therefore, the GLV oxidation products may remain as SOA after evaporation of the water droplet. The contribution of the identified oxidation products to SOA formation is estimated based on measured HPLC-ESI/MS responses relative to previous aqueous SOA mass yield measurements.

  20. Incubation of Aquilaria subintegra with Microbial Culture Supernatants Enhances Production of Volatile Compounds and Improves Quality of Agarwood Oil.

    Science.gov (United States)

    Monggoot, Sakon; Kulsing, Chadin; Wong, Yong Foo; Pripdeevech, Patcharee

    2018-06-01

    Incubation with microbial culture supernatants improved essential oil yield from Aquilaria subintegra woodchips. The harvested woodchips were incubated with de man, rogosa and sharpe (MRS) agar, yeast mold (YM) agar medium and six different microbial culture supernatants obtained from Lactobacillus bulgaricus , L. acidophilus , Streptococcus thermophilus , Lactococcus lactis , Saccharomyces carlsbergensis and S. cerevisiae prior to hydrodistillation. Incubation with lactic acid bacteria supernatants provided higher yield of agarwood oil (0.45% w/w) than that obtained from yeast (0.25% w/w), agar media (0.23% w/w) and water (0.22% w/w). The composition of agarwood oil from all media and microbial supernatant incubations was investigated by using gas chromatography-mass spectrometry. Overall, three major volatile profiles were obtained, which corresponded to water soaking (control), as well as, both YM and MRS media, lactic acid bacteria, and yeast supernatant incubations. Sesquiterpenes and their oxygenated derivatives were key components of agarwood oil. Fifty-two volatile components were tentatively identified in all samples. Beta-agarofuran, α-eudesmol, karanone, α-agarofuran and agarospirol were major components present in most of the incubated samples, while S. cerevisiae -incubated A. subintegra provided higher amount of phenyl acetaldehyde. Microbial culture supernatant incubation numerically provided the highest yield of agarwood oil compared to water soaking traditional method, possibly resulting from activity of extracellular enzymes produced by the microbes. Incubation of agarwood with lactic acid bacteria supernatant significantly enhanced oil yields without changing volatile profile/composition of agarwood essential oil, thus this is a promising method for future use.

  1. A novel process for volatile fatty acids production from syngas by integrating with mesophilic alkaline fermentation of waste activated sludge

    DEFF Research Database (Denmark)

    Rao, Yue; Wan, Jingjing; Liu, Yafeng

    2018-01-01

    The present study proposed and demonstrated a novel process for the bioconversion of syngas (mainly CO and H2) to valuable volatile fatty acids (VFA) by integrating with mesophilic alkaline fermentation of waste activated sludge (WAS). The results showed that although pH 9 was suitable for VFA...... to the mesophilic alkaline fermentation of WAS at pH 10 not only resulted in the enrichment of some known bacteria related with syngas conversion, but also changed the microbial community compositions for the fermentation of WAS....

  2. In vitro mineral nutrition of Curcuma longa L. affects production of volatile compounds in rhizomes after transfer to the greenhouse.

    Science.gov (United States)

    El-Hawaz, Rabia F; Grace, Mary H; Janbey, Alan; Lila, Mary Ann; Adelberg, Jeffrey W

    2018-06-18

    Turmeric is a rich source of bioactive compounds useful in both medicine and cuisine. Mineral concentrations effects (PO 4 3- , Ca 2+ , Mg 2+ , and KNO 3 ) were tested during in vitro rhizome development on the ex vitro content of volatile constituents in rhizomes after 6 months in the greenhouse. A response surface method (D-optimal criteria) was repeated in both high and low-input fertilizer treatments. Control plants were grown on Murashige and Skoog (MS) medium, acclimatized in the greenhouse and grown in the field. The volatile constituents were investigated by GC-MS. The total content of volatiles was affected by fertilizer treatments, and in vitro treatment with Ca 2+ and KNO 3 ; but PO 4 3- and Mg 2+ had no significant effect. The content was higher in the high-input fertilizer treatments (49.7 ± 9 mg/g DM) with 4 mM Ca 2+ , 60 mM KNO 3 and 5 mM NH 4 + , than the low-input fertilizer (26.6 ± 9 mg/g DM), and the MS control (15.28 ± 2.7 mg/g DM; 3 mM Ca 2+ , 20 mM K + , 39 mM NO 3 - , 20 mM NH 4 + , 1.25 mM PO 4 3- , and 1.5 mM Mg 2+ ). The interaction of Ca 2+ with KNO 3 affected curcumenol isomer I and II, germacrone, isocurcumenol, and β-elemenone content. Increasing in vitro phosphate concentration to 6.25 mM increased ex vitro neocurdione and methenolone contents. These results show that minerals in the in vitro bioreactor medium during rhizome development affected biosynthesis of turmeric volatile components after transfer to the greenhouse six months later. The multi-factor design identified 1) nutrient regulation of specific components within unique phytochemical profile for Curcuma longa L. clone 35-1 and 2) the varied phytochemical profiles were maintained with integrity during the greenhouse growth in high fertility conditions.

  3. Comparison of Three Methods for Extraction of Volatile Lipid Oxidation Products from Food Matrices for GC-MS Analysis

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Yesiltas, B.; Berner, Lis

    headspace extraction has been performed manually. Recently, automated dynamic headspace methods have become available. This presentation will summarize the principles of the different extraction methods. Moreover, results from fish oil, oil-in-water emulsion and milk obtained with SPME, manual dynamic...... headspace or automated dynamic headspace (TDU/DHS) extraction followed by GC-MS analysis will be compared. In all cases, concentrations of volatiles were quantified by calibration curves by addition of selected standards to oil, emulsion or milk. The results show that the linearity of calibration curves...

  4. A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.

    Science.gov (United States)

    Allaire, S E; Yates, S R; Ernst, F F; Gan, J

    2002-01-01

    There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models.

  5. 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...

  6. Implementation of online volatile fatty acids sensor for control and optimization of anaerobic process for low cost biogas production from manure. Project report

    Energy Technology Data Exchange (ETDEWEB)

    Boe, K.; Angelidaki, I.

    2010-10-15

    Proper monitoring and control can improve process stability and enhance process performance for better economy of the biogas plants. Volatile fatty acid (VFA) is the most widely recognized as a direct, relevant measure of stability. Classic on-line measurement of individual VFA is based on filtration, which suffers from fouling when applied with manure slurries. A VFA sensor developed at DTU Environment, based on headspace chromatography technique could avoid the problems from particulate matters. In this work, the sensor had been implemented for online monitoring of the lab-scale and the pilot-scale manure digester. The industrial prototype of the VFA sensor and sample acquisition system has been constructed and implemented at a pilot scale biogas plant, located at Lundtofte, DTU. The VFA sensor has shown very satisfying results in terms of sensitivity and reliability for monitoring the biogas process. Moreover, the online VFA and biogas registration data were used as process indicators for automatic control of the biogas reactor. The results from control experiments confirmed that the combination of biogas production, total VFA concentration and propionate concentration could effectively reflect the dynamic state of the process which was very crucial for automatic control. Due to the standardized analyzing condition (pH<2, temperature>70 deg. C), the sensor responses were not affected by the manure composition (TS, VS or the addition of extra organics), which made these results representative for implementing in the full-scale biogas plant where some industrial organic wastes were added to increase the biogas production. During the project period, the sensor design and construction had been modified and tested several times to improve the robustness. However, the implementation of the sensor in full-scale biogas plant would need some further development such as improvement of mechanical design and further up-scaling depending on the dry solid content in the

  7. 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....

  8. Essential time management how to become more productive and effective

    CERN Document Server

    Hilder, Brett

    2011-01-01

    Time is a resource like any other. Using your time effectively can transform your personal productivity and determine your level of success. Moreover, it can change your level of job satisfaction and confidence.

  9. Volatile fatty acids production from food waste: effects of pH, temperature, and organic loading rate.

    Science.gov (United States)

    Jiang, Jianguo; Zhang, Yujing; Li, Kaimin; Wang, Quan; Gong, Changxiu; Li, Menglu

    2013-09-01

    The effects of pH, temperature, and organic loading rate (OLR) on the acidogenesis of food waste have been determined. The present study investigated their effects on soluble chemical oxygen demand (SCOD), volatile fatty acids (VFAs), volatile solids (VS), and ammonia nitrogen (NH4(+)-N). Both the concentration and yield of VFAs were highest at pH 6.0, acetate and butyrate accounted for 77% of total VFAs. VFAs concentration and the VFA/SCOD ratio were highest, and VS levels were lowest, at 45 °C, but the differences compared to the values at 35 °C were slight. The concentrations of VFAs, SCOD, and NH4(+)-N increased as OLR increased, whereas the yield of VFAs decreased from 0.504 at 5 g/Ld to 0.306 at 16 g/Ld. Acetate and butyrate accounted for 60% of total VFAs. The percentage of acetate and valerate increased as OLR increased, whereas a high OLR produced a lower percentage of propionate and butyrate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. The impact of cold storage and ethylene on volatile ester production and aroma perception in 'Hort16A' kiwifruit.

    Science.gov (United States)

    Günther, Catrin S; Marsh, Ken B; Winz, Robert A; Harker, Roger F; Wohlers, Mark W; White, Anne; Goddard, Matthew R

    2015-02-15

    Fruit esters are regarded as key volatiles for fruit aroma. In this study, the effects of cold storage on volatile ester levels of 'Hort16A' (Actinidia chinensis Planch. var chinensis) kiwifruit were examined and the changes in aroma perception investigated. Cold storage (1.5°C) for two or four months of fruit matched for firmness and soluble solids concentration resulted in a significant reduction in aroma-related esters such as methyl/ethyl propanoate, methyl/ethyl butanoate and methyl/ethyl hexanoate. Levels of these esters, however, were restored by ethylene treatment (100ppm, 24h) before ripening. A sensory panel found that "tropical" and "fruit candy" aroma was stronger and "green" odour notes less intensively perceived in kiwifruit which were ethylene-treated after cold storage compared to untreated fruit. The key findings presented in this study may lead to further work on the ethylene pathway, and innovative storage and marketing solutions for current and novel fruit cultivars. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. In situ seasonal study of the volatile production of almonds (Prunus dulcis) var. 'Nonpareil' and relationship to navel orangeworm.

    Science.gov (United States)

    Beck, John J; Merrill, Glory B; Higbee, Bradley S; Light, Douglas M; Gee, Wai S

    2009-05-13

    Nonpareil almonds, Prunus dulcis , account for the largest percentage of almond varieties grown in the Central Valley of California. Several studies have investigated the various nonvolatile and volatile components of various plant parts; however, the volatile organic compound (VOC) emission of almonds from a single cultivar has not been studied over the course of a growing season. This aspect is particularly relevant to research concerning the navel orangeworm (NOW), a major insect pest of almonds and other tree nuts. Despite the continued presence of NOW, the identification of particular VOCs and their relationship to NOW have not been addressed. The VOC emission of Nonpareil almonds was collected in situ over the course of a growing season by solid-phase microextraction (SPME). The VOCs (Z)-hex-3-enyl acetate, (Z)-hex-3-enyl butyrate, undecan-2-ol, beta-bourbonene, and tetradecane were present for the majority of the days investigated. Several VOCs exhibited positive electroantennographic signals from male and/or female NOW moths.

  12. Volatility of V15Cr5Ti fusion reactor alloy

    International Nuclear Information System (INIS)

    Neilson, R.M. Jr.

    1986-01-01

    One potential hazard from the presence of activation products in fusion facilities is accidental oxidation-driven volatility of those activation products. Scoping experiments were conducted to investigate the oxidation and elemental volatility of candidate fusion reactor alloy V15Cr5Ti as a function of time, temperature, and test atmosphere. Experiments in air and in argon carrier gases containing 10 4 to 10 1 Pa (10 -1 to 10 -4 atm) oxygen were conducted to investigate the lower oxygen partial pressure limit for the formation of a low melting point (approximately 650 0 C), high volatility, oxide layer and its formation rate. Experiments to determine the elemental volatility of alloy constituents in air at temperatures of 700 0 C to greater than 1600 0 C. Some of these volatility experiments used V15Cr5Ti that was arc-remelted to incorporate small quantities (<0.1 wt. %) of Sc and Ca. Incorporation of Sc and Ca in test specimens permitted volatility measurement of radioactive constituents present only after activation of V15Cr5Ti

  13. Heuristics for the Economic Production Quantity Problem under Restrictions on Production and Maintenance Time

    Directory of Open Access Journals (Sweden)

    Qi Xu

    2016-01-01

    Full Text Available This paper proposes an economic production quantity problem with the maximal production run time and minimal preventive maintenance time over a finite planning horizon. The objective is to find the efficient production and maintenance policy to minimize the total cost composed of production, maintenance, shortages, and holding costs under the restriction on the production run time and the preventive maintenance time. The production and maintenance decisions include the production and maintenance frequencies and the production run and the maintenance time. The variability and the boundedness of the production run and maintenance time make the problem difficult to solve. Two heuristic algorithms are developed using different techniques based on the optimal properties of the relaxed problem. The performance comparison between the two algorithms is illustrated by numerical examples. The numerical results show that, for the most part, there exists a heuristic algorithm which is more effective than the other.

  14. Production planning of a perishable product with lead time and non-stationary demand

    NARCIS (Netherlands)

    Pauls-Worm, K.G.J.; Haijema, R.; Hendrix, E.M.T.; Rossi, R.; Vorst, van der J.G.A.J.

    2012-01-01

    We study a production planning problem for a perishable product with a fixed lifetime, under a service-level constraint. The product has a non-stationary stochastic demand. Food supply chains of fresh products like cheese and several crop products, are characterised by long lead times due to

  15. Assessing responsiveness of a volatile and seasonal supply chain

    DEFF Research Database (Denmark)

    Wong, Chee Yew; Arlbjørn, Jan Stentoft; Hvolby, Hans Henrik

    2006-01-01

    ‘‘market responsive’’ and ‘‘physically efficient’’ supply chains constitutes the backbone of this assessment. Four risk-influencing determinants—forecast uncertainty, demand variability, contribution margin, and time window of delivery are found suitable to assess the responsiveness of the toy supply chain......This paper describes a structural approach to assess the responsiveness of a volatile and seasonal supply chain. It is based on a case study in an international toy company. Fisher’s (Harvard Bus. Rev. 75(2) (1997) 105–117) Model of ‘‘innovative’’ and ‘‘functional’’ products and the corresponding...... with volatility, and to design for a responsive supply chain. These findings have also enabled the extension of Fisher’s Model to volatile supply chains. This new product differentiation model adds a physically responsive supply chain for ‘‘intermediate’’ products into the Fisher’s Model....

  16. 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.

  17. Fermentation behaviour and volatile compound production by agave and grape must yeasts in high sugar Agave tequilana and grape must fermentations.

    Science.gov (United States)

    Arrizon, Javier; Fiore, Concetta; Acosta, Guillermina; Romano, Patrizia; Gschaedler, Anne

    2006-01-01

    Few studies have been performed on the characterization of yeasts involved in the production of agave distilled beverages and their individual fermentation properties. In this study, a comparison and evaluation of yeasts of different origins in the tequila and wine industries were carried out for technological traits. Fermentations were carried out in high (300 g l(-1)) and low (30 g l(-1)) sugar concentrations of Agave tequilana juice, in musts obtained from Fiano (white) and Aglianico (red) grapes and in YPD medium (with 270 g l(-1) of glucose added) as a control. Grape yeasts exhibited a reduced performance in high-sugar agave fermentation, while both agave and grape yeasts showed similar fermentation behaviour in grape musts. Production levels of volatile compounds by grape and agave yeasts differed in both fermentations.

  18. Advanced BorobondTM Shields for Nuclear Materials Containment and BorobondTM Immobilization of Volatile Fission Products - Final CRADA Report

    International Nuclear Information System (INIS)

    Wagh, Arun S.

    2016-01-01

    Borobond is a company-proprietary material developed by the CRADA partner in collaboration with Argonne, and is based on Argonne's Ceramicrete technology. It is being used by DOE for nuclear materials safe storage, and Boron Products, LLC is the manufacturer and supplier of Borobond. The major objective of this project was to produce a more versatile composition of this material and find new applications. Major target applications were use for nuclear radiation shields, such as in dry storage casks; use in immobilization of most difficult waste streams, such as Hanford K-Basin waste; use for soluble and volatile fission products, such as Cs, Tc, Sr, and I; and use for corrosion and fire protection applications in nuclear facilities.

  19. 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.

  20. Volatile profile of cashews (Anacardium occidentale L.) from different geographical origins during roasting.

    Science.gov (United States)

    Agila, Amal; Barringer, Sheryl Ann

    2011-01-01

    Volatile compounds were quantified in the headspace of Indian, Vietnamese, and Brazilian cashews, both raw and during roasting by selected ion flow tube-mass spectrometry. The optimum roasting times based on color measurements were also determined. Raw cashews were oil roasted for 3 to 9 min at 143 °C and color and volatiles measured. An excellent correlation, following a pseudo 1st-order reaction, was found between L* value and roasting time; darkness increases as roasting time increases. The optimum roasting time was 6, 8, and 9 min for Vietnamese, Indian, and Brazilian cashews, respectively. Raw cashews had lower concentrations of volatiles than roasted cashews. Most volatiles significantly increased in concentration during roasting of Brazilian, Indian, and Vietnamese cashews. Only a few volatiles significantly decreased during roasting. Ethanol and 1-heptene significantly decreased during roasting in Brazilian cashews and toluene decreased in Vietnamese cashews. Brazilian cashews had significantly higher levels of most volatiles than Indian and Vietnamese cashews. Most volatile levels in Indian and Vietnamese cashews were not significantly different. Of the volatiles, Strecker aldehydes, including methylbutanal, 2-methylpropanal, and acetaldehyde, were at the highest concentration in roasted cashews. The Maillard reaction contributed to the formation of most of the volatiles in cashews from the 3 countries. There was also degradation of sugars to form furan-type compounds and oxidation of lipids to form alkanals such as hexanal. The volatile profile during roasting of cashews can be used to determine the best roasting time for each type of cashew. The rate of color development and the production of volatiles differ for the cashews from the 3 geographical locations. © 2011 Institute of Food Technologists®

  1. Herbivore-induced volatile production by Arabidopsis thaliana leads to attraction of the parasitoid Cotesia rubecula: chemical, behavioral, and gene-expression analysis

    NARCIS (Netherlands)

    Poecke, R.M.P.; Posthumus, M.A.; Dicke, M.

    2001-01-01

    Many plant species defend themselves against herbivorous insects indirectly by producing volatiles in response to herbivory. These volatiles attract carnivorous enemies of the herbivores. Research on the model plant Arabidopsis thaliana (L.) Heynh. has contributed considerably to the unraveling of

  2. 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.

  3. Effects of volatile fatty acids in biohydrogen effluent on biohythane production from palm oil mill effluent under thermophilic condition

    Directory of Open Access Journals (Sweden)

    Chonticha Mamimin

    2017-09-01

    Conclusion: Preventing the high concentration of butyric acid, and propionic acid in the hydrogenic effluent could enhance methane production in two-stage anaerobic digestion for biohythane production.

  4. Continuous fermentation of food waste leachate for the production of volatile fatty acids and potential as a denitrification carbon source.

    Science.gov (United States)

    Kim, Hakchan; Kim, Jaai; Shin, Seung Gu; Hwang, Seokhwan; Lee, Changsoo

    2016-05-01

    This study investigated the simultaneous effects of hydraulic retention time (HRT) and pH on the continuous production of VFAs from food waste leachate using response surface analysis. The response surface approximations (R(2)=0.895, p<0.05) revealed that pH has a dominant effect on the specific VFA production (PTVFA) within the explored space (1-4-day HRT, pH 4.5-6.5). The estimated maximum PTVFA was 0.26g total VFAs/g CODf at 2.14-day HRT and pH 6.44, and the approximation was experimentally validated by running triplicate reactors under the estimated optimum conditions. The mixture of the filtrates recovered from these reactors was tested as a denitrification carbon source and demonstrated superior performance in terms of reaction rate and lag length relative to other chemicals, including acetate and methanol. The overall results provide helpful information for better design and control of continuous fermentation for producing waste-derived VFAs, an alternative carbon source for denitrification. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Carbon Catabolite Repression Regulates the Production of the Unique Volatile Sodorifen of Serratia plymuthica 4Rx13

    Directory of Open Access Journals (Sweden)

    Nancy Magnus

    2017-12-01

    Full Text Available Microorganisms are capable of synthesizing a plethora of secondary metabolites including the long-overlooked volatile organic compounds. Little knowledge has been accumulated regarding the regulation of the biosynthesis of such mVOCs. The emission of the unique compound sodorifen of Serratia plymuthica isolates was significantly reduced in minimal medium with glucose, while succinate elevated sodorifen release. The hypothesis of carbon catabolite repression (CCR acting as a major control entity on the synthesis of mVOCs was proven by genetic evidence. Central components of the typical CCR of Gram-negative bacteria such as the adenylate cyclase (CYA, the cAMP binding receptor protein (CRP, and the catabolite responsive element (CRE were removed by insertional mutagenesis. CYA, CRP, CRE1 mutants revealed a lower sodorifen release. Moreover, the emission potential of other S. plymuthica isolates was also evaluated.

  6. Influence of growth regulators on distribution of trichomes and the production of volatiles in micropropagated plants of Plectranthus ornatus

    Directory of Open Access Journals (Sweden)

    Helna C. Passinho-Soares

    Full Text Available ABSTRACT The profile of volatile organic compounds, the glandular and non-glandular trichomes of Plectranthus ornatus, obtained by in vitro cultivation, was evaluated in plants grown in Murashide and Skoog medium supplemented with benylaminopurine at 4.5, 9.0, and 18.0 µM + naphthaleneacetic acid at 5.37 µM, kinetin at 4.7, 9.3 and 18.5 µM + naphthaleneacetic acid (5.37 µM or Murashide and Skoog 0 medium (as a control. Scanning Electron Microscopy was performed on samples of the third leaf node of the 90 days old plants obtained from treatment with 4.5 or 9.0 µM benylaminopurine, and 4.7 or 9.3 µM kinetin. Headspace Solid Phase Micro-Extraction of the 30, 60 and 90 days old in vitro plants permitted to determinate by GC/MS the composition comprised of 62 compounds. The data were analyzed using Principal Component Analysis and Hierarchical Clustering Analysis and, the major constituents of these oils after treatment and aging were monoterpenes and sesquiterpenes. Morphoanatomical analysis of trichomes, by Scanning Electron Microscopy, enabled the identification of non-glandular trichomes and four types of glandular trichomes, which comprised capitate and peltate glandular trichomes that were distributed on both sides of the leaf. We observed that the regulators influenced qualitative and quantitative profiles of the volatile organic compounds and the number and distribution of hairs on the leaf surface.

  7. Effect of oral nitroethane and 2-nitropropanol administration on methane-producing activity and volatile fatty acid production in the ovine rumen

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.C.; Callaway, T.R.; Schultz, C.L.; Edrington, T.S.; Harvey, R.B.; Nisbet, D.J. [United States Department of Agriculture, Agricultural Research Service, Food and Feed Safety Research Unit, College Station, TX (United States); Carstens, G.E.; Miller, R.K. [Texas A and M University, College Station, TX (United States). Department of Animal Science

    2006-12-15

    Strategies are sought to reduce economic and environmental costs associated with ruminant methane emissions. The effect of oral nitroethane or 2-nitropropanol administration on ruminal methane-producing activity and volatile fatty acid production was evaluated in mature ewes. Daily administration of 24 and 72 mg nitroethane/kg body weight reduced (P < 0.05) methane-producing activity by as much as 45% and 69% respectively, when compared to control animals given no nitroethane. A daily odes of 120 mg 2-nitropropanol/kg body weight was needed to reduce (P < 0.05) methane-producing activity by 37% from that of untreated control animals. Reductions in methane-producing activity may have been diminished by the last day (day 5) of treatment, presumably due to ruminal adaptation. Oral administration of nitroethane or 2-nitropropanol had little or no effect on accumulations or molar proportions of volatile fatty acids in ruminal contents collected from the sheep. These results demonstrate that nitroethane was superior to 2-nitropropanol as a methane inhibitor and that both nitrocompounds reduced ruminal methanogenesis in vivo without redirecting the flow of reductant generated during fermentation to propionate and butyrate. (author)

  8. Flexibility of production systems and prepare-finish time

    Directory of Open Access Journals (Sweden)

    Vukićević Milan R.

    2006-01-01

    Full Text Available One of the specificities of the large-serial and mass production is the almost neglected percentage of prepare-finish time in the production cycle. In the conditions of today dominant discontinuous production, it becomes a significant element of the production cycle. The eastern (Japan doctrine of increasing the flexibility of the production systems, is based inter alia also on the extreme reduction of the prepare-finish time. For this reason, the aim of this study was to identify the types and percentages of individual jobs within the group of prepare-finish jobs. The sample consisted of 3 (three production systems for the production of joinery, with the discontinuous production system. The research shows that the percentage of time of the jobs installation of work instruments, regulation of processing regime, and removal of work instruments is extremely long and that it ranges between 11.83% and 18.93% of the shift time. The reasons of the high percentage of these jobs are the wide range of products and the absence of the rationalisation of prepare-finish jobs. Within the efforts to minimize the effects of disruption and to increase the flexibility of the production systems, the rationalisation of prepare-finish jobs is the unavoidable condition.

  9. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

    Science.gov (United States)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

    2014-12-01

    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

  10. Production and Comprehension of Time Reference in Korean Nonfluent Aphasia

    Science.gov (United States)

    Lee, Jiyeon; Kwon, Miseon; Na, Hae Ri; Bastiaanse, Roelien; Thompson, Cynthia K.

    2015-01-01

    Objectives Individuals with nonfluent agrammatic aphasia show impaired production and comprehension of time reference via verbal morphology. However, cross-linguistic findings to date suggest inconsistent evidence as to whether tense processing in general is impaired or time reference to the past is selectively difficult in this population. This study examined production and comprehension of time reference via verb morphology in Korean-speaking individuals with nonfluent aphasia. Methods A group of 9 healthy controls and 8 individuals with nonfluent aphasia (5 for the production task) participated in the study. Sentence priming production and auditory sentence to picture matching tasks were used, parallel with the previous cross-linguistic experiments in English, Chinese, Turkish, and others. Results The participants with nonfluent aphasia showed different patterns of impairment in production and comprehension. In production, they were impaired in all time references with errors being dominated by substitution of incorrect time references and other morpho-phonologically well-formed errors, indicating a largely intact morphological affixation process. In comprehension, they showed selective impairment of the past, consistent with the cross-linguistic evidence from English, Chinese, Turkish, and others. Conclusion The findings suggest that interpretation of past time reference poses particular difficulty in nonfluent aphasia irrespective of typological characteristics of languages; however, in production, language-specific morpho-semantic functions of verbal morphology may play a significant role in selective breakdowns of time reference. PMID:26290861

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

    Science.gov (United States)

    Gottardo, Rossella; Mikšík, Ivan; Aturki, Zeineb; Sorio, Daniela; Seri, Catia; Fanali, Salvatore; Tagliaro, Franco

    2012-02-01

    The present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization-time of flight mass spectrometry (CZE-ESI-TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6-monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non-volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis-mass spectrometry (CE-MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Carbon monoxide production from five volatile anesthetics in dry sodalime in a patient model: halothane and sevoflurane do produce carbon monoxide; temperature is a poor predictor of carbon monoxide production

    Directory of Open Access Journals (Sweden)

    Perez Roberto SGM

    2005-06-01

    Full Text Available Abstract Background Desflurane and enflurane have been reported to produce substantial amounts of carbon monoxide (CO in desiccated sodalime. Isoflurane is said to produce less CO and sevoflurane and halothane should produce no CO at all. The purpose of this study is to measure the maximum amounts of CO production for all modern volatile anesthetics, with completely dry sodalime. We also tried to establish a relationship between CO production and temperature increase inside the sodalime. Methods A patient model was simulated using a circle anesthesia system connected to an artificial lung. Completely desiccated sodalime (950 grams was used in this system. A low flow anesthesia (500 ml/min was maintained using nitrous oxide with desflurane, enflurane, isoflurane, halothane or sevoflurane. For immediate quantification of CO production a portable gas chromatograph was used. Temperature was measured within the sodalime container. Results Peak concentrations of CO were very high with desflurane and enflurane (14262 and 10654 ppm respectively. It was lower with isoflurane (2512 ppm. We also measured small concentrations of CO for sevoflurane and halothane. No significant temperature increases were detected with high CO productions. Conclusion All modern volatile anesthetics produce CO in desiccated sodalime. Sodalime temperature increase is a poor predictor of CO production.

  13. Comparison of orthologous cyanobacterial aldehyde deformylating oxygenases in the production of volatile C3-C7 alkanes in engineered E. coli

    Directory of Open Access Journals (Sweden)

    Pekka Patrikainen

    2017-12-01

    Full Text Available Aldehyde deformylating oxygenase (ADO is a unique enzyme found exclusively in photosynthetic cyanobacteria, which natively converts acyl aldehyde precursors into hydrocarbon products embedded in cellular lipid bilayers. This capacity has opened doors for potential biotechnological applications aiming at biological production of diesel-range alkanes and alkenes, which are compatible with the nonrenewable petroleum-derived end-products in current use. The development of production platforms, however, has been limited by the relative inefficiency of ADO enzyme, promoting research towards finding new strategies and information to be used for rational design of enhanced pathways for hydrocarbon over-expression. In this work we present an optimized approach to study different ADO orthologs derived from different cyanobacterial species in an in vivo set-up in Escherichia coli. The system enabled comparison of alternative ADOs for the production efficiency of short-chain volatile C3-C7 alkanes, propane, pentane and heptane, and provided insight on the differences in substrate preference, catalytic efficiency and limitations associated with the enzymes. The work concentrated on five ADO orthologs which represent the most extensively studied cyanobacterial species in the field, and revealed distinct differences between the enzymes. In most cases the ADO from Nostoc punctiforme PCC 73102 performed the best in respect to yields and initial rates for the production of the volatile hydrocarbons. At the other extreme, the system harboring the ADO form Synechococcus sp. RS9917 produced very low amounts of the short-chain alkanes, primarily due to poor accumulation of the enzyme in E. coli. The ADOs from Synechocystis sp. PCC 6803 and Prochlorococcus marinus MIT9313, and the corresponding variant A134F displayed less divergence, although variation between chain-length preferences could be observed. The results confirmed the general trend of ADOs having

  14. Production of medium-chain volatile flavour esters in Pichia pastoris whole-cell biocatalysts with extracellular expression of Saccharomyces cerevisiae acyl-CoA: ethanol O-acyltransferase Eht1 or Eeb1

    DEFF Research Database (Denmark)

    Zhuang, Shiwen; Fu, Junshu; Powell, Chris

    2015-01-01

    Medium-chain volatile flavour esters are important molecules since they have extensive applications in food, fragrance, cosmetic, paint and coating industries, which determine different characteristics of aroma or taste in commercial products. Biosynthesis of these compounds by alcoholysis...... pastoris yeasts with functional extracellular expression of Eht1 or Eeb1 were constructed. Flavour production was established through an integrated process with coupled enzyme formation and ester biosynthesis in the recombinant yeasts in one pot, leading to the formation of volatile C6-C14 methyl and ethyl...

  15. Novel consortium of Klebsiella variicola and Lactobacillus species enhances the functional potential of fermented dairy products by increasing the availability of branched-chain amino acids and the amount of distinctive volatiles.

    Science.gov (United States)

    Rosales-Bravo, H; Morales-Torres, H C; Vázquez-Martínez, J; Molina-Torres, J; Olalde-Portugal, V; Partida-Martínez, L P

    2017-11-01

    Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. The identified consortium increases the functional potential of fermented dairy products. © 2017 The Society for Applied Microbiology.

  16. Volatile Gas Production by Methyl Halide Transferase: An In Situ Reporter Of Microbial Gene Expression In Soil.

    Science.gov (United States)

    Cheng, Hsiao-Ying; Masiello, Caroline A; Bennett, George N; Silberg, Jonathan J

    2016-08-16

    Traditional visual reporters of gene expression have only very limited use in soils because their outputs are challenging to detect through the soil matrix. This severely restricts our ability to study time-dependent microbial gene expression in one of the Earth's largest, most complex habitats. Here we describe an approach to report on dynamic gene expression within a microbial population in a soil under natural water levels (at and below water holding capacity) via production of methyl halides using a methyl halide transferase. As a proof-of-concept application, we couple the expression of this gas reporter to the conjugative transfer of a bacterial plasmid in a soil matrix and show that gas released from the matrix displays a strong correlation with the number of transconjugant bacteria that formed. Gas reporting of gene expression will make possible dynamic studies of natural and engineered microbes within many hard-to-image environmental matrices (soils, sediments, sludge, and biomass) at sample scales exceeding those used for traditional visual reporting.

  17. Emissions of volatile organic compounds during the ship-loading of petroleum products: Dispersion modelling and environmental concerns.

    Science.gov (United States)

    Milazzo, Maria Francesca; Ancione, Giuseppa; Lisi, Roberto

    2017-12-15

    Emissions due to ship-loading of hydrocarbons are currently not addressed neither by the Directive on the integrated pollution prevention or by other environmental regulations. The scope of this study is to point towards the environmental and safety concerns associated with such emissions, even if proper attention has not been given to this issue until now. In order to achieve this goal, the modelling of the emission volatile organic compounds (VOC), due to ship-load operations at refineries has been made by means of the definition of a simulation procedure which includes a proper treatment of the hours of calm. Afterwards, a quantitative analysis of VOC dispersion for an Italian case-study is presented with the primary aims: (i) to develop and verify the validity of the approach for the modelling of the emission sources and of the diffusion of these contaminants into the atmosphere by a proper treatment of the hours of calm and (ii) to identify their contribution to the total VOC emitted in a typical refinery. The calculated iso-concentration contours have also been drawn on a map and allowed the identification of critical areas for people protecting by the adoption of abatement solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Prediction of dioxin/furan incinerator emissions using low-molecular-weight volatile products of incomplete combustion.

    Science.gov (United States)

    Lemieux, P M; Lee, C W; Ryan, J V

    2000-12-01

    Emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from incinerators and other stationary combustion sources are of environmental concern because of the toxicity of certain PCDD/F congeners. Measurement of trace levels of PCDDs/Fs in combustor emissions is not a trivial matter. Development of one or more simple, easy-to-measure, reliable indicators of stack PCDD/F concentrations not only would enable incinerator operators to economically optimize system performance with respect to PCDD/F emissions, but could also provide a potential technique for demonstrating compliance status on a more frequent basis. This paper focuses on one approach to empirically estimate PCDD/F emissions using easy-to-measure volatile organic C2 chlorinated alkene precursors coupled with flue gas cleaning parameters. Three data sets from pilot-scale incineration experiments were examined for correlations between C2 chlorinated alkenes and PCDDs/Fs. Each data set contained one or more C2 chloroalkenes that were able to account for a statistically significant fraction of the variance in PCDD/F emissions. Variations in the vinyl chloride concentrations were able to account for the variations in the PCDD/F concentrations strongly in two of the three data sets and weakly in one of the data sets.

  19. Production Time Loss Reduction in Sauce Production Line by Lean Six Sigma Approach

    Science.gov (United States)

    Ritprasertsri, Thitima; Chutima, Parames

    2017-06-01

    In all industries, time losses, which are incurred in processing are very important. As a result, losses are incurred in productivity and cost. This research aimed to reduce lost time that occurs in sauce production line by using the lean six sigma approach. The main objective was to reduce the time for heating sauce which causes a lot of time lost in the production line which affects productivity. The methodology was comprised of the five-phase improvement model of Six Sigma. This approach begins with defining phase, measuring phase, analysing phase, improving phase and controlling phase. Cause-and-effect matrix and failure mode and effect analysis (FMEA) were adopted to screen the factors which affect production time loss. The results showed that the percentage of lost time from heating sauce reduced by 47.76%. This increased productivity to meet the plan.

  20. Total volatile fatty acids and bacterial production rates as affected by rations containing untreated or ammonia (urea) treated rice straw in croos-bred cattle

    International Nuclear Information System (INIS)

    Puri, J.P.; Gupta, B.N.

    1990-01-01

    An experiment was conducted to study the effect of feeding ammoniated rice straw on ruminal total volatile fatty acid (TVFA) and bacterial production rates. Twelve karan swiss, male, rumen fistulated calves (2-2.5 yrs) were divided in three equal groups. Animals were offered rice straw either untreated (A) or 4 per cent urea+40 per cent moisture treated and ensiled for 30 days (B) or 5 per cent urea+30 per cent moisture treated and ensiled for 30 days (C). Protein requirements were met through concentrate mixture. Levels of NH 3 -N and TCA-precipitable-N in strained rumen liquor (SRL) were significantly higher (20.34±0.022, 63.26±0.81 (B), 20.78±0.41, 64.98±0.87 (C) (mg/100 ml SRL) in groups fed ammoniated ±0.31, 45.94±1.91 mg/100 ml S RL), respectively. The bacterial production rates in the rumen (g/day) were significantly higher in groups B and C as compared to group A. TVFA concentrations (mmole/100 ml SRL ) and TVFA production rates (mmole/d) were also significantly higher in groups B and C as compared to group A. The bacterial production rates were significantly co-related with TVFA, NH 3 -N, TCA precipitable-N concentration in the rumen and ATP production. Multiple regression equations relating bacterial production rates with (i)NH 3 -N and TVFA concentration in the rumen, (ii)NH 3 -N and TVFA production rates and (iii)NH 3 -N and ATP produced were also developed. (author). 18 refs., 2 tabs

  1. 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.

  2. Real-time, in-situ detection of volatile profiles for the prevention of aflatoxin fungal contamination in pistachios

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tiziana C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Center of Micro and Nano Technology, Material Engineering Division; Chang, Allan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Center of Micro and Nano Technology, Material Engineering Division; Zhou, Jenny [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Center of Micro and Nano Technology, Material Engineering Division

    2017-10-18

    The objective in this project is to provide a proof of concept will demonstrate the feasibility of a Raman, in-situ warning system for detecting and removing developing fungal hot spots from pistachio stockpiles and transit containers, thus decreasing human health risks and product loss as a result of contamination. The proposed project has the following goals: to calibrate the Raman fingerprinting of biomarkers, standalone and in premixed samples, to build a database with the vibrational profiles distinctive to the signatures of the bouquet emitted by the contaminated pistachios; to test the improvement in the detection of the detectable markers with enhanced Raman on a small probe.

  3. Characterization of the volatile profiles of beer using headspace solid-phase microextraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Rossi, Serena; Sileoni, Valeria; Perretti, Giuseppe; Marconi, Ombretta

    2014-03-30

    The objective of this study was a multivariate characterization of the volatile profile of beers. Such a characterization is timely considering the increasing worldwide consumption of beer, the continuous growth of microbreweries and the importance of volatile compounds to beer flavour. A method employing solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) was optimized and then applied to a sample set of 36 industrial and craft beers of various styles and fermentation types. The volatile profiles of different beer styles is described, with particular attention paid to the volatile compounds characteristic of a spontaneously fermented lambic raspberry framboise beer. Furthermore, it was also possible to identify which specific volatile compounds are principally responsible for the differences in the volatile profiles of top- and bottom-fermented beers. Moreover, a volatile fingerprint of the craft top-fermented Italian beers was defined, as they show a very similar volatile profile. Finally, the volatile compounds that are characteristic of the bock-style beers are described. The SPME-GC-MS analytical method optimized in this study is suitable for characterizing the volatile fingerprint of different beers, especially on the basis of the kind of fermentation (top, bottom or spontaneous), the method of production and the style of the beer. © 2013 Society of Chemical Industry.

  4. The effect of organic loading rate and retention time on hydrogen production from a methanogenic CSTR.

    Science.gov (United States)

    Pakarinen, O; Kaparaju, P; Rintala, J

    2011-10-01

    The possibility of shifting a methanogenic process for hydrogen production by changing the process parameters viz., organic loading rate (OLR) and hydraulic retention time (HRT) was evaluated. At first, two parallel semi-continuously fed continuously stirred tank reactors (CSTR) were operated as methanogenic reactors (M1 and M2) for 78 days. Results showed that a methane yield of 198-218 L/kg volatile solids fed (VS(fed)) was obtained when fed with grass silage at an OLR of 2 kgVS/m³/d and HRT of 30 days. After 78 days of operation, hydrogen production was induced in M2 by increasing the OLR from 2 to 10 kgVS/m³/d and shortening the HRT from 30 to 6 days. The highest H₂ yield of 42 L/kgVS(fed) was obtained with a maximum H₂ content of 24%. The present results thus demonstrate that methanogenic process can be shifted towards hydrogen production by increasing the OLR and decreasing HRT. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. A continuous-time control model on production planning network ...

    African Journals Online (AJOL)

    A continuous-time control model on production planning network. DEA Omorogbe, MIU Okunsebor. Abstract. In this paper, we give a slightly detailed review of Graves and Hollywood model on constant inventory tactical planning model for a job shop. The limitations of this model are pointed out and a continuous time ...

  6. Effect of Retention Time on Biogas Production from Poultry ...

    African Journals Online (AJOL)

    A study was carried out on different retention times in the anaerobic fermentation of slurry from poultry droppings and cassava peels. The system adopted in this work was batch-type. Daily gas production fell slightly from 130 to 32 litres as retention time was increased from 10 to 40 days for poultry droppings. For cassava ...

  7. Doping-assisted low-pressure photoionization mass spectrometry for the real-time detection of lung cancer-related volatile organic compounds.

    Science.gov (United States)

    Li, Zhen; Xu, Ce; Shu, Jinian; Yang, Bo; Zou, Yao

    2017-04-01

    Real-time detection of lung cancer-related volatile organic compounds (VOCs) is a promising, non-intrusive technique for lung cancer (LC) prescreening. In this study, a novel method was designed to enhance the detection selectivity and sensitivity of LC-related polar VOCs by dichloromethane (CH 2 Cl 2 ) doping-assisted low-pressure photoionization mass spectrometry (LPPI-MS). Compared with conventional LPPI-MS, CH 2 Cl 2 doping-assisted LPPI-MS boosted the peak intensities of n-propanol, n-pentanal, acetone, and butyl acetate in nitrogen specifically by 53, 18, 16, and 43 times, respectively. The signal intensities of their daughter ions were inhibited or reduced. At relative humidity (RH) of 20%, the sensitivities of n-propanol, n-pentanal, acetone, and butyl acetate detection ranged from 116 to 452 counts/ppbv with a detection time of 10s and R 2 >0.99 for the linear calibration curves. The method was also applicable under higher RH levels of 50% and 90%. Breath samples obtained from 10 volunteers and spiked samples were investigated. Eight-fold enhancements in the signal intensities of polar VOCs were observed in the normal and spiked samples. These preliminary results demonstrate the efficacy of the dichloromethane doping-assisted LPPI technique for the detection of LC-related polar VOCs. Further studies are indispensible to illustrating the detailed mechanism and applying the technique to breath diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Effect of organic fertilizers prepared from organic waste materials on the production of antibacterial volatile organic compounds by two biocontrol Bacillus amyloliquefaciens strains.

    Science.gov (United States)

    Raza, Waseem; Wei, Zhong; Ling, Ning; Huang, Qiwei; Shen, Qirong

    2016-06-10

    Three organic fertilizers made of different animal and plant waste materials (BOFs) were evaluated for their effects on the production of antibacterial volatile organic compounds (VOCs) by two Bacillus amyloliquefaciens strains SQR-9 and T-5 against the tomato wilt pathogen Ralstonia solanacearum (RS). Both strains could produce VOCs that inhibited the growth and virulence traits of RS; however, in the presence of BOFs, the production of antibacterial VOCs was significantly increased. The maximum inhibition of growth and virulence traits of RS by VOCs of T-5 and SQR-9 was determined at 1.5% BOF2 and 2% BOF3, respectively. In case of strain T-5, 2-nonanone, nonanal, xylene, benzothiazole, and butylated hydroxy toluene and in case of strain SQR-9, 2-nonanone, nonanal, xylene and 2-undecanone were the main antibacterial VOCs whose production was increased in the presence of BOFs. The results of this study reveal another significance of using organic fertilizers to improve the antagonistic activity of biocontrol agents against phytopathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Time Domain Partitioning of Electricity Production Cost Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hummon, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jones, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hale, E. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Production cost models are often used for planning by simulating power system operations over long time horizons. The simulation of a day-ahead energy market can take several weeks to compute. Tractability improvements are often made through model simplifications, such as: reductions in transmission modeling detail, relaxation of commitment variable integrality, reductions in cost modeling detail, etc. One common simplification is to partition the simulation horizon so that weekly or monthly horizons can be simulated in parallel. However, horizon partitions are often executed with overlap periods of arbitrary and sometimes zero length. We calculate the time domain persistence of historical unit commitment decisions to inform time domain partitioning of production cost models. The results are implemented using PLEXOS production cost modeling software in an HPC environment to improve the computation time of simulations while maintaining solution integrity.

  10. The Cellulolytic Activity And Volatile Fatty Acid Product Of Rumen Bacteria Of Buffalo And Cattle On Rice Straw, Elephant Grass, and Sesbania Leaves Substrates

    Directory of Open Access Journals (Sweden)

    Caribu Hadi Prayitno

    1999-01-01

    Full Text Available Experiment on The Cellulolytic Activity and Volatile Fatty Acid Product of Rumen Bacteria of Buffalo and Cattle on Rice Straw, Elephant Grass, and Sesbania Leaves Substrates had been conducted at Feedstuff Laboratory of Animal Science Soedirman University. The basic design  that was used in this experiment was Completely Randomized Design (CRD with factorial pattern of 6 x 3, three replications. The bacteria isolate as the factors were cellulolytic rumen bacteria isolate of buffalo (A1, A2, and A3 and cattle (A4, A5 and A6 while the substrates (second factor  were NDF rice straw (S1, elephant grass (S2, and sesbania leaves (S3 Cell walls. The result of this experiment showed that the interaction between bacteria isolate and substrate  type were significant on pH, NDF digestibility, cellulase activity, pH was  6.28 until 6.43.  The NDF digestibility range was 12.27 until 55.61 percent. The lowers of cellulase activity was 5.11 IU/ml and the higher was 24.47 IU/ml. The range of acetic acid yield was 63.37 to 307.467 mg/100 ml. Range of  propionic production was 15.17 to 352.20 mg/ 100 ml. The production of butiric acid was 8.77 to 40.87 mg/ 100 ml. The cellulase activity  of cellulolytic rumen bacteria of buffalo was higher than cattle, and also their effect on NDF digestibility of rice straw, elephant grass, and sesbania leaves cell walls. The A3 of cellulolytic rumen bacteria isolate of  buffalo changed cell walls substrat to volatile fatty  acid was more effective than cattle, especially on cell elephant grass. Propionic and butiric  acid that was produced by cellulolytic rumen bacteria isolate of buffalo more higher than cattle (Animal Production 1 (1 : 1-9 (1999 Key Words: Cellulolytic, VFA, Rumen Bacteria, Buffalo, Cattle.

  11. Discrete-Time Filter Synthesis using Product of Gegenbauer Polynomials

    OpenAIRE

    N. Stojanovic; N. Stamenkovic; I. Krstic

    2016-01-01

    A new approximation to design continuoustime and discrete-time low-pass filters, presented in this paper, based on the product of Gegenbauer polynomials, provides the ability of more flexible adjustment of passband and stopband responses. The design is achieved taking into account a prescribed specification, leading to a better trade-off among the magnitude and group delay responses. Many well-known continuous-time and discrete-time transitional filter based on the classical polynomial approx...

  12. 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

  13. Method for sampling and analysis of volatile biomarkers in process gas from aerobic digestion of poultry carcasses using time-weighted average SPME and GC-MS.

    Science.gov (United States)

    Koziel, Jacek A; Nguyen, Lam T; Glanville, Thomas D; Ahn, Heekwon; Frana, Timothy S; Hans van Leeuwen, J

    2017-10-01

    A passive sampling method, using retracted solid-phase microextraction (SPME) - gas chromatography-mass spectrometry and time-weighted averaging, was developed and validated for tracking marker volatile organic compounds (VOCs) emitted during aerobic digestion of biohazardous animal tissue. The retracted SPME configuration protects the fragile fiber from buffeting by the process gas stream, and it requires less equipment and is potentially more biosecure than conventional active sampling methods. VOC concentrations predicted via a model based on Fick's first law of diffusion were within 6.6-12.3% of experimentally controlled values after accounting for VOC adsorption to the SPME fiber housing. Method detection limits for five marker VOCs ranged from 0.70 to 8.44ppbv and were statistically equivalent (p>0.05) to those for active sorbent-tube-based sampling. The sampling time of 30min and fiber retraction of 5mm were found to be optimal for the tissue digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Highly reconfigurable production systems controlled by real-time agents

    OpenAIRE

    Schütz, D.;Schraufstetter, M.;Folmer, J.;Vogel-Heuser, B.;Gmeiner, T.;Shea, K.

    2017-01-01

    Flexible plant components can significantly increase the flexibility of manufacturing systems and enable concepts like mass-customized production. This paper presents an approach for production planning and execution for flexible manufacturing system components, based on software agents. The agents are implemented directly on a PLC, making them capable of real-time operation. Additionally, a service-interface contributes to the vertical integration of the approach into the higher level planni...

  15. Goods-Time Elasticity of Substitution in Health Production.

    Science.gov (United States)

    Du, Juan; Yagihashi, Takeshi

    2017-11-01

    We examine how inputs for health production, in particular, medical care and health-enhancing time, are combined to improve health. The estimated elasticity of substitution from a constant elasticity of substitution production function is significantly less than one for the working-age population, rejecting the unit elasticity of substitution used in previous studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Use of a plant-derived enzyme template for the production of the green-note volatile hexanal.

    Science.gov (United States)

    Schade, Frank; Thompson, John E; Legge, Raymond L

    2003-11-05

    Hexanal is a key organoleptic element of green-note that is found in both fragrances and flavors. We report a novel process for the production of hexanal using immobilized enzyme templates extracted from different plant sources in combination with hollow-fiber ultrafiltration for in situ separation. Enzyme templates, known to be responsible for the synthesis of hexanal from linoleic acid (18:2), were isolated from naturally enriched tissues including carnation petals, strawberry and tomato leaves. These templates were immobilized in an alginate matrix and used as a biocatalyst in a packed-bed bioreactor. Continuous product recovery was achieved using a hollow-fiber ultrafiltration unit. The effects of pH, reaction temperature, and substrate and enzyme concentrations were studied and their effects on hexanal generation identified and optimized. Utilizing optimized conditions, hexanal production 112-fold higher than endogenous steady-state levels in a corresponding amount of plant tissue could be achieved over a 30-minute period. Based on the reactor studies, product inhibition also appears to be an important factor for bioreactor-based hexanal production. Copyright 2003 Wiley Periodicals, Inc.

  17. Estimation of biogenic volatile organic compound (BVOC) emissions from the terrestrial ecosystem in China using real-time remote sensing data

    Science.gov (United States)

    Li, M.; Huang, X.; Li, J.; Song, Y.

    2012-04-01

    Because of the high emission intensity and reactivity, biogenic volatile organic compounds (BVOCs) play a significant role in the terrestrial ecosystems, human health, secondary pollution, global climate change and the global carbon cycle. Past estimations of BVOC emissions in China were based on outdated algorithms and limited meteorological data, and there have been significant inconsistences between the land surface parameters of dynamic models and those of BVOC estimation models, leading to large inaccuracies in the estimated results. To refine BVOC emission estimations for China and to further explore the role of BVOCs in atmospheric chemical processes, we used the latest algorithms of MEGAN (Model of Emissions of Gases and Aerosols from Nature) with MM5 (the Fifth-Generation Mesoscale Model) providing highly resolved meteorological data, to estimate the biogenic emissions of isoprene (C5H8) and seven monoterpene species (C10H16) in 2006. Real-time MODIS (Moderate Resolution Imaging Spectroradiometer) data were introduced to update the land surface parameters and improve the simulation performance of MM5, and to modify the influence of leaf area index (LAI) and leaf age deviation from standard conditions. In this study, the annual BVOC emissions for the whole country totaled 12.97 Tg C, a relevant value much lower than that given in global estimations but higher than the past estimations in China. Therein, the most important individual contributor was isoprene (9.36 Tg C), followed by α-pinene (1.24 Tg C yr-1) and β-pinene (0.84 Tg C yr-1). Due to the considerable regional disparity in plant distributions and meteorological conditions across China, BVOC emissions presented significant spatial-temporal variations. Spatially, isoprene emission was concentrated in South China, which is covered by large areas of broadleaf forests and shrubs. On the other hand, Southeast China was the top-ranking contributor of monoterpenes, in which the dominant vegetation

  18. A stochastic surplus production model in continuous time

    DEFF Research Database (Denmark)

    Pedersen, Martin Wæver; Berg, Casper Willestofte

    2017-01-01

    surplus production model in continuous time (SPiCT), which in addition to stock dynamics also models the dynamics of the fisheries. This enables error in the catch process to be reflected in the uncertainty of estimated model parameters and management quantities. Benefits of the continuous-time state......Surplus production modelling has a long history as a method for managing data-limited fish stocks. Recent advancements have cast surplus production models as state-space models that separate random variability of stock dynamics from error in observed indices of biomass. We present a stochastic......-space model formulation include the ability to provide estimates of exploitable biomass and fishing mortality at any point in time from data sampled at arbitrary and possibly irregular intervals. We show in a simulation that the ability to analyse subannual data can increase the effective sample size...

  19. Solid phase extraction in combination with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry for the detailed investigation of volatiles in South African red wines

    NARCIS (Netherlands)

    Weldegergis, B.T.; Crouch, A.M.; Górecki, T.; Villiers, de A.

    2011-01-01

    Comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC × GC–TOFMS) has been applied for the analysis of volatile compounds in three young South African red wines. In spite of the significant benefits offered by GC × GC–TOFMS for the separation and

  20. Timing of product introduction in network economies under heterogeneous demand

    DEFF Research Database (Denmark)

    Winther, Christian Dahl

    This paper studies the introduction of a new and incompatible technology in a spatial market with network externalities. In competition with an established network, the entrant chooses how long to do research and a level of product differentiation, which determine the adoption patterns of consumers...... level of product differentiation that should be chosen by the sponsor of the new technology in equilibrium. Third, the formal relationship between these variables are derived under compatibility.  Fourth, the entering firm's problem is solved by numerical methods to gain insight into the optimal linkage...... between research time and product design....

  1. Implementation of a new gamma spectrometer on the MERARG loop: Application to the volatile fission products release measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, S.; Gleizes, B.; Pontillon, Y.; Hanus, E.; Ducros, G. [CEA, DEN, DEC, SA3C, F-13108, Saint Paul lez Durance, (France); Roure, C. [CEA, DEN, DTN, SMTA, F-13108, Saint Paul lez Durance, (France)

    2015-07-01

    The MERARG facility initially aims at the annealing of irradiated fuel samples to study the gaseous fission products release kinetics. In order to complete the evaluation of the source term potentially released during accidental situation, the MERARG experimental circuit has been enhanced with a new gamma spectrometer. This one is directly sighting the fuel and is devoted to the fission products release kinetics. Because of the specificities of the fuel measurements, it has been dimensioned and designed to match the specific requirements. The acquisition chain and the collimation system have been optimized for this purpose and a first set of two experiments have shown the good functioning of this new spectrometry facility. (authors)

  2. Identification of volatile butyl rubber thermal-oxidative degradation products by cryofocusing gas chromatography/mass spectrometry (cryo-GC/MS).

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jonell Nicole; White, Michael Irvin; Bernstein, Robert; Hochrein, James Michael

    2013-02-01

    Chemical structure and physical properties of materials, such as polymers, can be altered as aging progresses, which may result in a material that is ineffective for its envisioned intent. Butyl rubber formulations, starting material, and additives were aged under thermal-oxidative conditions for up to 413 total days at up to 124 ÀC. Samples included: two formulations developed at Kansas City Plant (KCP) (#6 and #10), one commercially available formulation (#21), Laxness bromobutyl 2030 starting material, and two additives (polyethylene AC-617 and Vanax MBM). The low-molecular weight volatile thermal-oxidative degradation products that collected in the headspace over the samples were preconcentrated, separated, and detected using cryofocusing gas chromatography mass spectrometry (cryo-GC/MS). The majority of identified degradation species were alkanes, alkenes, alcohols, ketones, and aldehydes. Observations for Butyl #10 aged in an oxygen-18 enriched atmosphere (18O2) were used to verify when the source of oxygen in the applicable degradation products was from the gaseous environment rather than the polymeric mixture. For comparison purposes, Butyl #10 was also aged under non-oxidative thermal conditions using an argon atmosphere.

  3. Enhanced ethanol production, volatile compound biosynthesis and fungicide removal during growth of a newly isolated Saccharomyces cerevisiae strain on enriched pasteurized grape musts

    Energy Technology Data Exchange (ETDEWEB)

    Sarris, Dimitris; Kotseridis, Yorgos; Galiotou-Panayotou, Maria; Papanikolaou, Seraphim [Department of Food Science and Technology, Agricultural University of Athens (Greece); Linga, Maria [Oinognosia, Wine analysis and consulting, Kiato (Greece)

    2009-02-15

    The kinetic behavior of a newly isolated Saccharomyces cerevisiae strain, grown on pasteurized grape musts enriched with industrial sugars, was studied after the addition of various concentrations [0.0 (reference), 0.4 and 2.4 mg/L] of the fungicide quinoxyfen to the medium. Batch-flask cultures were carried out. Significant quantities of biomass (10.0{+-}0.8 g/L) were produced regardless of quinoxyfen addition to the medium; therefore, the addition of the fungicide did not seriously inhibit biomass production. Ethanol was synthesized in very high quantities in all trials (highest concentrations 106.4-119.2 g/L). A slight decrease of ethanol production in terms of both absolute value and conversion yield of ethanol produced per sugar consumed was, however, observed when the quinoxyfen concentration was increased. The addition of quinoxyfen led to significantly lower ethylic ester levels, which also pertains to the acetates analyzed in this study. Fusel alcohol synthesis seemed to be activated when 0.4 mg/L quinoxyfen was added, but at 2.4 mg/L of added fungicide, no statistically significant differences were observed compared with the control trial. Volatile acid levels did not present a uniform trend in relation with the added fungicide. Finally, the fermentation was accompanied by a significant reduction of the fungicide concentration (79-82 wt% fungicide removal). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  4. Norm-times : a design for production time and variability reduction for Faes Cases

    NARCIS (Netherlands)

    Karandeinos, Georgios

    2008-01-01

    This project deals with the production process of Faes Cases business unit. This company is producing custom-made packaging and sells standard solutions with customized interior. During the last years, it was observed that the throughput time of the production is increasing and is hard to forecast

  5. Volatile times for the very first ionic liquid: understanding the vapor pressures and enthalpies of vaporization of ethylammonium nitrate.

    Science.gov (United States)

    Emel'yanenko, Vladimir N; Boeck, Gisela; Verevkin, Sergey P; Ludwig, Ralf

    2014-09-08

    A hundred years ago, Paul Walden studied ethyl ammonium nitrate (EAN), which became the first widely known ionic liquid. Although EAN has been investigated extensively, some important issues still have not been addressed; they are now tackled in this communication. By combining experimental thermogravimetric analysis with time of flight mass spectrometry (TGA-ToF-MS) and transpiration method with theoretical methods, we clarify the volatilisation of EAN from ambient to elevated temperatures. It was observed that up to 419 K, EAN evaporates as contact-ion pairs leading to very low vapour pressures of a few Pascal. Starting from 419 K, the decomposition to nitric acid and ethylamine becomes more thermodynamically favourable than proton transfer. This finding was supported by DFT calculations, which provide the free energies of all possible gas-phase species, and show that neutral molecules dominate over ion pairs above 500 K, an observation that is in nearly prefect agreement with the experimental boiling point of 513 K. This result is crucial for the ongoing practical applications of protic ionic liquids such as electrolytes for batteries and fuel cells because, in contrast to high-boiling conventional solvents, EAN exhibits no significant vapour pressure below 419 K and this property fulfils the requirements for the thermal behaviour of safe electrolytes. Overall, EAN shows the same barely measurable vapour pressures as typical aprotic ionic liquids at temperatures only 70 K lower. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effects of host gut-derived probiotic bacteria on gut morphology, microbiota composition and volatile short chain fatty acids production of Malaysian Mahseer Tor tambroides

    Directory of Open Access Journals (Sweden)

    Md. Asaduzzaman

    2018-02-01

    Full Text Available Three host-associated probiotics (Bacillus sp. AHG22, Alcaligenes sp. AFG22, and Shewanella sp. AFG21 were isolated from the gastrointestinal tract of Tor tambroides, and their effects were evaluated on gut morphology, microbiota composition and volatile short chain fatty acids (VSCFAs production of the same species. A control diet (40% crude protein and 10% lipid was formulated, and three different probiotic supplemented diets were prepared by immersing the control diet in each host-derived isolated probiotic, suspended in sterile phosphate buffered saline (PBS, to achieve concentration at 1.0 × 108 CFU g−1 feed. Triplicate groups of T. tambroides juveniles (1.39 ± 0.06 g were stocked in twelve glass aquaria (100 L capacity with stocking density of 20 individuals per aquarium. The feed was applied twice daily at 3.0% of the body weight per day for 90 days. The intake of probiotics drastically modified the gut microbiota composition. The average number of OTUs, Shannon index and Margalef species richness were significantly higher in host-associated probiotic treatments compared to the control. A significant increase of lipolytic, proteolytic and cellulolytic bacterial number were observed in the gastrointestinal tracts of T. tambroides fed the diets supplemented with Alcaligenes sp. AFG22 compared to the control. Villus length, villus width and villus area were significantly higher in T. tambroides juveniles fed the diet supplemented with Alcaligenes sp. AFG22. Acetate and butyrate were detected as main VSCFA production in the gastrointestinal tract of T. tambroides. Acetate and total VSCFAs production in Alcaligenes sp. AFG22 supplemented treatment was significantly higher than control. These results indicate that host-derived probiotics, especially Alcaligenes sp. has a significant potential as an important probiotic to enhance the nutrients utilization and metabolism through increasing gut surface area and VSCFAs

  7. DONKEY MILK SHELF LIFE: MICROBIOLOGY AND VOLATILE COMPOUNDS

    Directory of Open Access Journals (Sweden)

    F. Conte

    2010-03-01

    Full Text Available Organoleptics properties are important to evaluate the shelf life of food products. Sensory analysis is generally used for this purpose. In this study psychrotrophic, mesophilic bacteria, and pH values were correlated to volatile compounds. The quality of raw donkey milk stored for 3, 7, 10, 14 and 28 days at two different temperatures (3°C and 7°C was tested. Donkey milk volatiles for the first time in this study were identified. Different volatiles distribution were detected by Smart Nose and GCO during the trials and a correlation with bacteriological and pH data were shown. On the basis of the results the acceptability of 10 days storing at +3°C, and of 3-4 days at +7°C, for milk samples, was pointed out.

  8. Production and Trade Situation in Iran and USA and Impact of Exchange rate Volatility on the Exports

    OpenAIRE

    M. Salarpour; S. Mojarad; M. Sabouhi

    2015-01-01

    In the present study, pistachio production and trade and influential factors on its exports in Iran and the USA are compared the the .Using the annual data from 1970 to 2011; this study aimed to analyze the effects of pistachio price and the effects of food security. Moreover, the relationship between exchange rate and pistachio export in the Iranian economy was analyzed through examining a non linear relation between the two factors. Therefore, the hypothesis validation upon nonlinearity re...

  9. The Biological Diversity and Production of Volatile Organic Compounds by Stem-Inhabiting Endophytic Fungi of Ecuador

    OpenAIRE

    Rundell, Susan; Spakowicz, Daniel; Narváez-Trujillo, Alexandra; Strobel, Scott

    2015-01-01

    Fungal endophytes colonize every major lineage of land plants without causing apparent harm to their hosts. Despite their production of interesting and potentially novel compounds, endophytes—particularly those inhabiting stem tissues—are still a vastly underexplored component of microbial diversity. In this study, we explored the diversity of over 1500 fungal endophyte isolates collected from three Ecuadorian ecosystems: lowland tropical forest, cloud forest, and coastal dry forest. We sough...

  10. Effects of solvent volatilization time on the bond strength of etch-and-rinse adhesive to dentin using conventional or deproteinization bonding techniques.

    Science.gov (United States)

    de Sousa Júnior, José Aginaldo; Carregosa Santana, Márcia Luciana; de Figueiredo, Fabricio Eneas Diniz; Faria-E-Silva, André Luis

    2015-08-01

    This study determined the effect of the air-stream application time and the bonding technique on the dentin bond strength of adhesives with different solvents. Furthermore, the content and volatilization rate of the solvents contained in the adhesives were also evaluated. Three adhesive systems with different solvents (Stae, SDI, acetone; XP Bond, Dentsply De Trey, butanol; Ambar, FGM, ethanol) were evaluated. The concentrations and evaporation rates of each adhesive were measured using an analytical balance. After acid-etching and rinsing, medium occlusal dentin surfaces of human molars were kept moist (conventional) or were treated with 10% sodium hypochlorite for deproteinization. After applying adhesives over the dentin, slight air-stream was applied for 10, 30 or 60 sec. Composite cylinders were built up and submitted to shear testing. The data were submitted to ANOVA and Tukey's test (α = 0.05). Stae showed the highest solvent content and Ambar the lowest. Acetone presented the highest evaporation rate, followed by butanol. Shear bond strengths were significantly affected only by the factors of 'adhesive' and 'bonding technique' (p Stae showed the lowest bond strength values (p < 0.05), while no significant difference was observed between XP Bond and Ambar. Despite the differences in content and evaporation rate of the solvents, the duration of air-stream application did not affect the bond strength to dentin irrespective of the bonding technique.

  11. Effect of mixed liquor volatile suspended solids (MLVSS and hydraulic retention time (HRT on the performance of activated sludge process during the biotreatment of real textile wastewater

    Directory of Open Access Journals (Sweden)

    Kapil Kumar

    2014-03-01

    Full Text Available Adequate information is available on colour and organics removal in batch mode using pure microbial cultures from dye contaminated wastewater. There was a need to develop environment friendly and cost effective treatment technique for actual field conditions. Therefore, the present study was undertaken with an aim to evaluate the potential of acclimatized mixed microbial consortia for the removal of colour and organics from real textile wastewater. Experiments were performed in laboratory scale activated sludge process (ASP unit under steady state condition, varying mixed liquor volatile suspended solids (MLVSS (2500, 3500 and 5000 mg/l and hydraulic retention time (HRT (18, 24 and 36 h. The results showed that decolourization and chemical oxygen demand (COD removal increased with increase in MLVSS and HRT. At 18 h HRT, decolourization was found to be 46, 54 and 67%, which increased to 67, 75 and 90% (36 h HRT at 2500, 3500 and 5000 mg/l MLVSS, respectively. COD removal was found to be 62, 73 and 77% (at 18 h HRT which increased to 77, 85 and 91% (36 h HRT at 2000, 3500 and 5000 mg/l MLVSS, respectively. On the basis of the results obtained in this study suitable treatment techniques can be developed for the treatment of wastewater contaminated with variety of dyes in continuous mode of operation. This shall have the advantage of treatment of larger quantity of wastewater in shorter duration.

  12. Modeling the dynamic volatile fatty acids profiles with pH and hydraulic retention time in an anaerobic baffled reactor during the startup period.

    Science.gov (United States)

    Shi, En; Li, Jianzheng; Leu, Shao-Yuan; Antwi, Philip

    2016-12-01

    To predict the dynamic profiles in volatile fatty acids (VFAs) with pH and hydraulic retention time (HRT) during the startup of a 4-compartment ABR, a mathematical model was constructed by introducing pH and thermodynamic inhibition functions into the biochemical processes derived from the ADM1. The calibration of inhibition parameter for propionate uptake effectively improved the prediction accuracy of VFAs. The developed model could simulate the VFAs profiles very well no matter the observable change of pH or/and HRT. The simulation results indicated that both H 2 -producing acetogenesis and methanogenesis in the ABR would be inhibited with a pH less than 4.61, and the propionate oxidation could be thermodynamically restricted even with a neutral pH. A decreased HRT would enhanced the acidogenesis and H 2 -producing acetogenesis in the first 3 compartments, but no observable increase in effluent VFAs could be found due to the synchronously enhanced methanogenesis in the last compartment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. An economic production model for time dependent demand with rework and multiple production setups

    Directory of Open Access Journals (Sweden)

    S.R. Singh

    2014-04-01

    Full Text Available In this paper, we present a model for time dependent demand with multiple productions and rework setups. Production is demand dependent and greater than the demand rate. Production facility produces items in m production setups and one rework setup (m, 1 policy. The major reason of reverse logistic and green supply chain is rework, so it reduces the cost of production and other ecological problems. Most of the researchers developed a rework model without deteriorating items. A numerical example and sensitivity analysis is shown to describe the model.

  14. Neural correlates of time versus money in product evaluation

    Directory of Open Access Journals (Sweden)

    Sebastian eLehmann

    2012-10-01

    Full Text Available The common saying time is money reflects the widespread belief in many people’s everyday life that time is valuable like money. Psychologically and neurophysiologically, however, these concepts seem to be quite different. This research replicates prior behavioral investigations by showing that merely mentioning time (compared to merely mentioning money leads participants to evaluate a product more positively. Beyond this finding, the present functional magnetic resonance imaging (fMRI experiment provides novel insight into the neurophysiological underpinnings of this behavioral effect by showing that more positive product evaluations in the time primes (compared to money primes are preceded by increased activation in the insula. Our data, therefore, support the idea of a time mindset that is different from a money mindset. Studies on the functional neuroanatomy of the insula have implicated this brain area in distinct but related psychological phenomena such as urging, addiction, loss aversion, and love. These functions imply greater personal connection between the consumer and a target subject or object and, thus, help explain why time-primed consumers rate products more positively.

  15. Identify and Manage the Software Requirements Volatility

    OpenAIRE

    Khloud Abd Elwahab; Mahmoud Abd EL Latif; Sherif Kholeif

    2016-01-01

    Management of software requirements volatility through development of life cycle is a very important stage. It helps the team to control significant impact all over the project (cost, time and effort), and also it keeps the project on track, to finally satisfy the user which is the main success criteria for the software project. In this research paper, we have analysed the root causes of requirements volatility through a proposed framework presenting the requirements volatility causes and how...

  16. The peak of oil production-Timings and market recognition

    International Nuclear Information System (INIS)

    Almeida, Pedro de; Silva, Pedro D.

    2009-01-01

    Energy is essential for present societies. In particular, transportation systems depend on petroleum-based fuels. That world oil production is set to pass a peak is now a reasonably accepted concept, although its date is far from consensual. In this work, we analyze the true expectations of the oil market participants about the future availability of this fundamental energy source. We study the evolution through time of the curves of crude oil futures prices, and we conclude that the market participants, among them the crude oil producers, already expect a near-term peak of oil production. This agrees with many technical predictions for the date of peak production, including our own, that point to peak dates around the end of the present decade. If this scenario is confirmed, it can cause serious social and economical problems because societies will have little time to perform the necessary adjustments

  17. Effect of Retention Time on Biogas Production from Poultry ...

    African Journals Online (AJOL)

    JPC

    Daily gas production fell slightly from 130 to 32 litres as retention time was ... The continuing energy crisis has reawakened interest in the anaerobic ... and hydrogen sulfide (H2S2): 0.3 vol.%. ..... Nigerian Journal of Solar Energy 15: 80 – 85.

  18. The Times Higher Education Ranking Product: Visualising Excellence through Media

    Science.gov (United States)

    Stack, Michelle L.

    2013-01-01

    This paper will examine the Times Higher Education's (THE) World University Rankings as a corporate media product. A number of empirical studies have critiqued the methodology of the THE, yet individuals, Higher Education Institutions (HEIs) and governments continue to use them for decision-making. This paper analyses the influence of…

  19. The Triggers, Timing and Speed of New Product Price Landings

    NARCIS (Netherlands)

    C. Hernández-Mireles (Carlos); D. Fok (Dennis); Ph.H.B.F. Franses (Philip Hans)

    2008-01-01

    textabstractMany high-tech products and durable goods exhibit exactly one significant price cut some time after their launch. We call this sudden transition from high to low prices the price landing. In this paper we present a new model that describes two important features of price landings: their

  20. Designing life-time recycling loops for elastomer products

    NARCIS (Netherlands)

    Noordermeer, Jacques; Dierkes, Wilma; Blume, Anke; Dijkhuis, Kuno; van Hoek, Hans; Reuvekamp, Louis; Saiwari, Siti

    2017-01-01

    With depletion of natural resources and growing awareness of the limited capabilities of the globe to cope with pollution, the need to design life-time recycling loops for all types of products is steadily increasing. Rubber articles of all sorts and the need for a proper disposal of these at the

  1. Stock return, seasonality and asymmetric conditional volatility in steel & iron subsector

    Directory of Open Access Journals (Sweden)

    V. Chirila

    2015-01-01

    Full Text Available This paper presents the results obtained following the testing of five hypotheses regarding conditional return and volatility of the most listed European stocks in the steel & iron subsector. The following elements of the stocks are analysed: time variation of volatility, seasonality of return and volatility, relationship between return and volatility and volatility asymmetry. The results obtained confirm for all the analyzed stocks the existence of volatility variation in time, the lack of correlation between return and volatility, the existence of asymmetry phenomenon of volatility and the presence in some stocks of the seasonality effect both for return and volatility.

  2. Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain

    Directory of Open Access Journals (Sweden)

    Kathrine Holmgaard Bak

    2018-02-01

    Full Text Available There is a growing market for the use of hydrolysates from animal side-streams for production of high-protein supplements. However, there can be issues with development of off-flavors, either due to the raw material in question or due to the hydrolysis process itself. This study examined the development of volatile compounds during hydrolysis of hemoglobin. Briefly, porcine hemoglobin was hydrolyzed by 0.5% papain for up to 5 h, and the development of volatile compounds was analyzed via gas chromatography-mass spectrometry. The results showed that there was significant development of a number of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found in a control without enzyme.

  3. Real-Time Tropospheric Delay Estimation using IGS Products

    Science.gov (United States)

    Stürze, Andrea; Liu, Sha; Söhne, Wolfgang

    2014-05-01

    The Federal Agency for Cartography and Geodesy (BKG) routinely provides zenith tropospheric delay (ZTD) parameter for the assimilation in numerical weather models since more than 10 years. Up to now the results flowing into the EUREF Permanent Network (EPN) or E-GVAP (EUMETNET EIG GNSS water vapour programme) analysis are based on batch processing of GPS+GLONASS observations in differential network mode. For the recently started COST Action ES1206 about "Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate" (GNSS4SWEC), however, rapid updates in the analysis of the atmospheric state for nowcasting applications require changing the processing strategy towards real-time. In the RTCM SC104 (Radio Technical Commission for Maritime Services, Special Committee 104) a format combining the advantages of Precise Point Positioning (PPP) and Real-Time Kinematic (RTK) is under development. The so-called State Space Representation approach is defining corrections, which will be transferred in real-time to the user e.g. via NTRIP (Network Transport of RTCM via Internet Protocol). Meanwhile messages for precise orbits, satellite clocks and code biases compatible to the basic PPP mode using IGS products are defined. Consequently, the IGS Real-Time Service (RTS) was launched in 2013 in order to extend the well-known precise orbit and clock products by a real-time component. Further messages e.g. with respect to ionosphere or phase biases are foreseen. Depending on the level of refinement, so different accuracies up to the RTK level shall be reachable. In co-operation of BKG and the Technical University of Darmstadt the real-time software GEMon (GREF EUREF Monitoring) is under development. GEMon is able to process GPS and GLONASS observation and RTS product data streams in PPP mode. Furthermore, several state-of-the-art troposphere models, for example based on numerical weather prediction data, are implemented. Hence, it

  4. Discrete-Time Filter Synthesis using Product of Gegenbauer Polynomials

    Directory of Open Access Journals (Sweden)

    N. Stojanovic

    2016-09-01

    Full Text Available A new approximation to design continuoustime and discrete-time low-pass filters, presented in this paper, based on the product of Gegenbauer polynomials, provides the ability of more flexible adjustment of passband and stopband responses. The design is achieved taking into account a prescribed specification, leading to a better trade-off among the magnitude and group delay responses. Many well-known continuous-time and discrete-time transitional filter based on the classical polynomial approximations(Chebyshev, Legendre, Butterworth are shown to be a special cases of proposed approximation method.

  5. Production and Trade Situation in Iran and USA and Impact of Exchange rate Volatility on the Exports

    Directory of Open Access Journals (Sweden)

    M. Salarpour

    2015-05-01

    Full Text Available In the present study, pistachio production and trade and influential factors on its exports in Iran and the USA are compared the the .Using the annual data from 1970 to 2011; this study aimed to analyze the effects of pistachio price and the effects of food security. Moreover, the relationship between exchange rate and pistachio export in the Iranian economy was analyzed through examining a non linear relation between the two factors. Therefore, the hypothesis validation upon nonlinearity relationship between exchange rate and pistachio export was analyzed using smooth transition autoregressive model (STAR. The results of smooth transition model (STAR show that there is a nonlinear Granger causality between exchange rate and pistachio export and vice versa. It is therefore recommended ,in order to determine the threshold level of potential benefits of pistachio exports, the existence of the nonlinear relationship between the dynamic exchange rate and pistachio exports should be considered. Furthermore, in order to maintain market share in the international level, understanding target markets of export and achieving complete information upon the position of the major competitors in the production and trade of Pistachio is essential.

  6. Analysis of labor employment assessment on production machine to minimize time production

    Science.gov (United States)

    Hernawati, Tri; Suliawati; Sari Gumay, Vita

    2018-03-01

    Every company both in the field of service and manufacturing always trying to pass efficiency of it’s resource use. One resource that has an important role is labor. Labor has different efficiency levels for different jobs anyway. Problems related to the optimal allocation of labor that has different levels of efficiency for different jobs are called assignment problems, which is a special case of linear programming. In this research, Analysis of Labor Employment Assesment on Production Machine to Minimize Time Production, in PT PDM is done by using Hungarian algorithm. The aim of the research is to get the assignment of optimal labor on production machine to minimize time production. The results showed that the assignment of existing labor is not suitable because the time of completion of the assignment is longer than the assignment by using the Hungarian algorithm. By applying the Hungarian algorithm obtained time savings of 16%.

  7. Current status of fluoride volatility method development

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  8. Production of poly(hydroxybutyrate-hydroxyvalerate) from waste organics by the two-stage process: focus on the intermediate volatile fatty acids.

    Science.gov (United States)

    Shen, Liang; Hu, Hongyou; Ji, Hongfang; Cai, Jiyuan; He, Ning; Li, Qingbiao; Wang, Yuanpeng

    2014-08-01

    The two-stage process, coupling volatile fatty acids (VFAs) fermentation and poly(hydroxybutyrate-hydroxyvalerate) (P(HB/HV)) biosynthesis, was investigated for five waste organic materials. The overall conversion efficiencies were glycerol>starch>molasses>waste sludge>protein, meanwhile the maximum P(HB/HV) (1.674 g/L) was obtained from waste starch. Altering the waste type brought more effects on VFAs composition other than the yield in the first stage, which in turn greatly changed the yield in the second stage. Further study showed that even-number carbon VFAs (or odd-number ones) had a good positive linear relationship with P(HB/HV) content of HB (or HV). Additionally, VFA producing microbiota was analyzed by pyrosequencing methods for five wastes, which indicated that specific species (e.g., Lactobacillus for protein; Ethanoligenens for starch; Ruminococcus and Limnobacter for glycerol) were dominant in the community for VFAs production. Potential competition among acidogenic bacteria specially involved to produce some VFA was proposed as well. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Production of Volatile Compounds in Reconstituted Milk Reduced-Fat Cheese and the Physicochemical Properties as Affected by Exopolysaccharide-Producing Strain

    Directory of Open Access Journals (Sweden)

    Weijun Wang

    2012-12-01

    Full Text Available The application of the exopolysaccharide-producing strains for improving the texture and technical properties of reduced-fat cheese looks very promising. Streptococcus thermophilus TM11 was evaluated for production of reduced-fat cheese using reconstituted milk powder (CRMP. The physicochemical analysis of fresh and stored cheeses showed that this strain slightly increased moisture content resulting in cheese with higher yield and lower protein content compared to the direct acidified cheese. The volatiles of cheese were determined by SPME and GC equipped with a mass spectrometer. The results indicated that the major compounds included aldehydes, ketones and acids, whereas, alcohols and branched-chain aldehydes that contribute to exciting and harsh flavors were not found in CRMP. By the textural profile analysis, we found the cheese made with S. thermophilus TM11 had lower cohesiveness, resilience and higher adhesiveness than the direct acidified cheese, and had similar hardness. Further, S. thermophilus TM11 greatly changed the protein matrix with more opened cavities according to observation by scanning electron microscopy. Consequently, use of S. thermophilus TM11 could endow CRMP with the novel and suitable flavor properties and improved texture quality.

  10. 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.

  11. Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

    Energy Technology Data Exchange (ETDEWEB)

    Benítez-Guerrero, Mónica, E-mail: monica_benitez_guerrero@yahoo.es [Departamento de Ingeniería Civil, Materiales y Fabricación, Universidad de Málaga, Escuela de Ingenierías, C/ Dr. Ortiz Ramos s/n, Campus Teatinos, 29071 Málaga (Spain); López-Beceiro, Jorge [Departamento de Ingeniería Industrial II, Escola Politécnica Superior, Universidade da Coruña, Avda. Mendizábal, 15403 Ferrol (Spain); Sánchez-Jiménez, Pedro E. [Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, C/ Américo Vespucio 49, 41092 Sevilla (Spain); Pascual-Cosp, José [Departamento de Ingeniería Civil, Materiales y Fabricación, Universidad de Málaga, Escuela de Ingenierías, C/ Dr. Ortiz Ramos s/n, Campus Teatinos, 29071 Málaga (Spain)

    2014-04-01

    Highlights: • Thermal decomposition of sisal fibers has been discussed. • Decompositions of lignocellulosic components and sisal are compared by TXRD and TG-FTIR. • Hot washing reduces the temperature range in which sisal decomposition occurs. • Sisal cellulose decomposition goes by an alternative route to levoglucosan generation. - Abstract: This paper presents in a comprehensive way the thermal behavior of natural and hot-washed sisal fibers, based on the fundamental components of lignocellulosic materials: cellulose, xylan and lignin. The research highlights the influence exerted on the thermal stability of sisal fibers by other constituents such as non-cellulosic polysaccharides (NCP) and mineral matter. Thermal changes were investigated by thermal X-ray diffraction (TXRD), analyzing the crystallinity index (%Ic) of cellulosic samples, and by simultaneous thermogravimetric and differential thermal analysis coupled with Fourier-transformed infrared spectrometry (TG/DTA-FTIR), which allowed to examine the evolution of the main volatile compounds evolved during the degradation under inert and oxidizing atmospheres. The work demonstrates the potential of this technique to elucidate different steps during the thermal decomposition of sisal, providing extensible results to other lignocellulosic fibers, through the analysis of the evolution of CO{sub 2}, CO, H{sub 2}O, CH{sub 4}, acetic acid, formic acid, methanol, formaldehyde and 2-butanone, and comparing it with the volatile products from pyrolysis of the biomass components. The hydroxyacetaldehyde detected during pyrolysis of sisal is indicative of an alternative route to that of levoglucosan, generated during cellulose pyrolysis. Hot-washing at 75 °C mostly extracts non-cellulosic components of low decomposition temperature, and reduces the range of temperature in which sisal decomposition occurs, causing a retard in the pyrolysis stage and increasing Tb{sub NCP} and Tb{sub CEL}, temperatures at the

  12. 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.

  13. 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.

  14. The effect of SO2 on the production of ethanol, acetaldehyde, organic acids, and flavor volatiles during industrial cider fermentation.

    Science.gov (United States)

    Herrero, Mónica; García, Luis A; Díaz, Mario

    2003-05-21

    SO(2) is widely used in cider fermentation but also in other alcoholic beverages such as wine. Although the authorized limit is 200 ppm total SO(2), the International Organizations recommend its total elimination or at least reduction due to health concerns. Addition of SO(2) to apple juice at levels frequently used in industrial cidermaking (100 mg/L) induced significantly higher acetaldehyde production by yeast than that obtained without SO(2). Although the practical implications of acetaldehyde evolution under cidermaking conditions has been overcome by research and few data are available, this compound reached levels in two 2000 L bioreactors that may have prevented the occurrence of simultaneous alcoholic and malolactic fermentation. It was observed that malolactic fermentation had a positive effect promoting reduction of acetaldehyde levels in cider fermented with juice, SO(2)-treated or not. The addition of SO(2) clearly delayed malolactic fermentation comparing to the control, affecting not the onset of the malolactic fermentation but the rate of malic acid degradation. This compound, however, had a stimulatory effect on alcoholic fermentation.

  15. 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.

  16. Time-ordered product expansions for computational stochastic system biology

    International Nuclear Information System (INIS)

    Mjolsness, Eric

    2013-01-01

    The time-ordered product framework of quantum field theory can also be used to understand salient phenomena in stochastic biochemical networks. It is used here to derive Gillespie’s stochastic simulation algorithm (SSA) for chemical reaction networks; consequently, the SSA can be interpreted in terms of Feynman diagrams. It is also used here to derive other, more general simulation and parameter-learning algorithms including simulation algorithms for networks of stochastic reaction-like processes operating on parameterized objects, and also hybrid stochastic reaction/differential equation models in which systems of ordinary differential equations evolve the parameters of objects that can also undergo stochastic reactions. Thus, the time-ordered product expansion can be used systematically to derive simulation and parameter-fitting algorithms for stochastic systems. (paper)

  17. Reactive flash volatilization of fluid fuels

    Science.gov (United States)

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

    2013-01-08

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

  18. Effects of solvent volatilization time on the bond strength of etch-and-rinse adhesive to dentin using conventional or deproteinization bonding techniques

    Directory of Open Access Journals (Sweden)

    José Aginaldo de Sousa Júnior

    2015-08-01

    Full Text Available Objectives This study determined the effect of the air-stream application time and the bonding technique on the dentin bond strength of adhesives with different solvents. Furthermore, the content and volatilization rate of the solvents contained in the adhesives were also evaluated. Materials and Methods Three adhesive systems with different solvents (Stae, SDI, acetone; XP Bond, Dentsply De Trey, butanol; Ambar, FGM, ethanol were evaluated. The concentrations and evaporation rates of each adhesive were measured using an analytical balance. After acid-etching and rinsing, medium occlusal dentin surfaces of human molars were kept moist (conventional or were treated with 10% sodium hypochlorite for deproteinization. After applying adhesives over the dentin, slight air-stream was applied for 10, 30 or 60 sec. Composite cylinders were built up and submitted to shear testing. The data were submitted to ANOVA and Tukey's test (α = 0.05. Results Stae showed the highest solvent content and Ambar the lowest. Acetone presented the highest evaporation rate, followed by butanol. Shear bond strengths were significantly affected only by the factors of 'adhesive' and 'bonding technique' (p < 0.05, while the factor 'duration of air-stream' was not significant. Deproteinization of dentin increased the bond strength (p < 0.05. Stae showed the lowest bond strength values (p < 0.05, while no significant difference was observed between XP Bond and Ambar. Conclusions Despite the differences in content and evaporation rate of the solvents, the duration of air-stream application did not affect the bond strength to dentin irrespective of the bonding technique.

  19. Improving wheat productivity through source and timing of nitrogen fertilization

    International Nuclear Information System (INIS)

    Jan, M.T.; Khan, A.; Afridi, M.Z.; Arif, M.; Khan, M.J.; Farhatullah; Jan, D.; Saeed, M.

    2011-01-01

    Efficient nitrogen (N) fertilizer management is critical for the improved production of wheat (Triticum aestivum L.) and can be achieved through source and timing of N application. Thus, an experiment was carried out at the Research Farm of KPK Agricultural University Peshawar during 2005-06 to test the effects of sources and timing of N application on yield and yield components of wheat. Nitrogen sources were ammonium (NH/sub 4/) and nitrate (NO/sub 3/) applied at the rate of 100 kg ha/sup -1/ at three different stages i.e., at sowing (S1), tillering (S2) and boot stage (S3). Ammonium N increased yield component but did not affect the final grain yield. Split N application at sowing, tillering and boot stages had increased productive tillers m-2, and thousand grains weight, whereas grain yield was higher when N was applied at tillering and boot stages. Nitrogen fertilization increased 20% grain yield compared to control regardless of N application time. It was concluded from the experiment that split application of NH/sub 4/-N performed better than full dose application and/or NO/sub 3/-N for improved wheat productivity and thus, is recommended for general practice in agro-climatic conditions of Peshawar. (author)

  20. The predictive content of CBOE crude oil volatility index

    Science.gov (United States)

    Chen, Hongtao; Liu, Li; Li, Xiaolei

    2018-02-01

    Volatility forecasting is an important issue in the area of econophysics. The information content of implied volatility for financial return volatility has been well documented in the literature but very few studies focus on oil volatility. In this paper, we show that the CBOE crude oil volatility index (OVX) has predictive ability for spot volatility of WTI and Brent oil returns, from both in-sample and out-of-sample perspectives. Including OVX-based implied volatility in GARCH-type volatility models can improve forecasting accuracy most of time. The predictability from OVX to spot volatility is also found for longer forecasting horizons of 5 days and 20 days. The simple GARCH(1,1) and fractionally integrated GARCH with OVX performs significantly better than the other OVX models and all 6 univariate GARCH-type models without OVX. Robustness test results suggest that OVX provides different information from as short-term interest rate.

  1. Odour Detection Threshold Determination of Volatile Compounds in Topical Skin Formulations

    DEFF Research Database (Denmark)

    Thomsen, Birgitte Raagaard; Hyldig, Grethe; Taylor, Robert

    2018-01-01

    determination and also odour description by a trained sensory panel. In one case, the odour detection threshold value was 50 times higher (less detectable) in skin care products than in water, whereas for other volatile compounds the odour detection threshold value was only 1.5 times higher. The odour...

  2. Development of an analytical method coupling cell membrane chromatography with gas chromatography-mass spectrometry via microextraction by packed sorbent and its application in the screening of volatile active compounds in natural products.

    Science.gov (United States)

    Li, Miao; Wang, Sicen; He, Langchong

    2015-01-01

    Natural products (NPs) are important sources of lead compounds in modern drug discovery. To facilitate the screening of volatile active compounds in NPs, we have developed a new biochromatography method that uses rat vascular smooth muscle cells (VSMC), which are rich in L-type calcium channels (LCC), to prepare the stationary phase. This integrated method, which couples cell membrane chromatography (CMC) with gas chromatography-mass spectrometry (GC-MS) via microextraction by packed sorbent (MEPS) technology, has been termed VSMC/CMC-MEPS-GC-MS. Methodological validation confirmed its specificity, reliability and convenience. Screening results for Radix Angelicae Dahuricae and Fructus Cnidii obtained using VSMC/CMC-MEPS-GC-MS were consistent with those obtained using VSMC/CMC-offline-GC-MS. MEPS connection plays as simplified solid-phase extraction and replaces the uncontrollable evaporation operation in reported offline connections, so our new method is supposed to be more efficient and reliable than the offline ones, especially for compounds that are volatile, thermally unstable or difficult to purify. In application, senkyunolide A and ligustilide were preliminary identified as the volatile active components in Rhizoma Chuanxiong. We have thus confirmed the suitability of VSMC/CMC-MEPS-GC-MS for volatile active compounds screening in NP. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. On the non-causal link between volatility and growth

    DEFF Research Database (Denmark)

    Posch, Olaf; Wälde, Klaus

    A model highlighting the endogeneity of both volatility and growth is presented. Volatility and growth are therefore correlated but there is no causal link from volatility to growth. This joint endogeneity is illustrated by working out the effects through which economies with different tax levels...... di er both in their volatility and growth. Using a continuous-time DSGE model with plausible parametric restrictions, we obtain closedform measures of macro volatility based on cyclical components and output growth rates. Given our results, empirical volatility-growth analysis should include controls...

  4. Real-Time Quantification of Traces of Biogenic Volatile Selenium Compounds in Humid Air by Selected Ion Flow Tube Mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Sovová, Kristýna; Shestivska, Violetta; Španěl, Patrik

    2012-01-01

    Roč. 84, č. 11 (2012), s. 4979-4983 ISSN 0003-2700 R&D Projects: GA ČR GA203/09/0256 Institutional support: RVO:61388955 Keywords : Indian Mustard * volatilization * breath Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.695, year: 2012

  5. 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

  6. Relationships among gas production, end products of rumen fermentation and microbial N produced in vitro at two incubation times

    DEFF Research Database (Denmark)

    Cattani, Mirko; Maccarana, Laura; Hansen, Hanne Helene

    2013-01-01

    at 48 h. At t½, the valerate content in rumen fl uid was negligible. However, relatively large amounts of valerate were measured after 48 h, probably the result of microbial lysis. Results suggest that relationships among end-products of rumen fermentation can be more accurately evaluated at a substrate...... for ammonia N (N-NH3), volatile fatty acids (VFA), residual NDF and N bound to residual NDF (N-NDF). Values of GP were also predicted from VFA. Microbial N (MN) was computed as the difference between N present at the beginning and at the end of incubation. At 48 h, the relationship between GP measured...

  7. Real time information management for improving productivity in metallurgical complexes

    International Nuclear Information System (INIS)

    Bascur, O.A.; Kennedy, J.P.

    1999-01-01

    Applying the latest information technologies in industrial plants has become a serious challenge to management and technical teams. The availability of real time and historical operations information to identify the most critical part of the processing system from mechanical integrity is a must for global plant optimization. Expanded use of plant information on the desktop is a standard tool for revenue improvement, cost reduction, and adherence to production constraints. The industrial component desktop supports access to information for process troubleshooting, continuous improvement and innovation by plant and staff personnel. Collaboration between groups enables the implementation of an overall process effectiveness index based on losses due to equipment availability, production and product quality. The key to designing technology is to use the Internet based technologies created by Microsoft for its marketplace-office automation and the Web. Time derived variables are used for process analysis, troubleshooting and performance assessment. Connectivity between metallurgical complexes, research centers and their business system has become a reality. Two case studies of large integrated mining/metallurgical complexes are highlighted. (author)

  8. Time series analysis of gold production in Malaysia

    Science.gov (United States)

    Muda, Nora; Hoon, Lee Yuen

    2012-05-01

    Gold is a soft, malleable, bright yellow metallic element and unaffected by air or most reagents. It is highly valued as an asset or investment commodity and is extensively used in jewellery, industrial application, dentistry and medical applications. In Malaysia, gold mining is limited in several areas such as Pahang, Kelantan, Terengganu, Johor and Sarawak. The main purpose of this case study is to obtain a suitable model for the production of gold in Malaysia. The model can also be used to predict the data of Malaysia's gold production in the future. Box-Jenkins time series method was used to perform time series analysis with the following steps: identification, estimation, diagnostic checking and forecasting. In addition, the accuracy of prediction is tested using mean absolute percentage error (MAPE). From the analysis, the ARIMA (3,1,1) model was found to be the best fitted model with MAPE equals to 3.704%, indicating the prediction is very accurate. Hence, this model can be used for forecasting. This study is expected to help the private and public sectors to understand the gold production scenario and later plan the gold mining activities in Malaysia.

  9. Enteric methane production, rumen volatile fatty acid concentrations, and milk fatty acid composition in lactating Holstein-Friesian cows fed grass silage- or corn silage-based diets.

    Science.gov (United States)

    van Gastelen, S; Antunes-Fernandes, E C; Hettinga, K A; Klop, G; Alferink, S J J; Hendriks, W H; Dijkstra, J

    2015-03-01

    The objective of this study was to determine the effects of replacing grass silage (GS) with corn silage (CS) in dairy cow diets on enteric methane (CH4) production, rumen volatile fatty acid concentrations, and milk fatty acid (FA) composition. A completely randomized block design experiment was conducted with 32 multiparous lactating Holstein-Friesian cows. Four dietary treatments were used, all having a roughage-to-concentrate ratio of 80:20 based on dry matter (DM). The roughage consisted of either 100% GS, 67% GS and 33% CS, 33% GS and 67% CS, or 100% CS (all DM basis). Feed intake was restricted (95% of ad libitum DM intake) to avoid confounding effects of DM intake on CH4 production. Nutrient intake, apparent digestibility, milk production and composition, nitrogen (N) and energy balance, and CH4 production were measured during a 5-d period in climate respiration chambers after adaptation to the diet for 12 d. Increasing CS proportion linearly decreased neutral detergent fiber and crude protein intake and linearly increased starch intake. Milk production and milk fat content (on average 23.4 kg/d and 4.68%, respectively) were not affected by increasing CS inclusion, whereas milk protein content increased quadratically. Rumen variables were unaffected by increasing CS inclusion, except the molar proportion of butyrate, which increased linearly. Methane production (expressed as grams per day, grams per kilogram of fat- and protein-corrected milk, and as a percent of gross energy intake) decreased quadratically with increasing CS inclusion, and decreased linearly when expressed as grams of CH4 per kilogram of DM intake. In comparison with 100% GS, CH4 production was 11 and 8% reduced for the 100% CS diet when expressed per unit of DM intake and per unit fat- and protein-corrected milk, respectively. Nitrogen efficiency increased linearly with increased inclusion of CS. The concentration of trans C18:1 FA, C18:1 cis-12, and total CLA increased quadratically, and

  10. TIME MANAGEMENT AND ITS IMPLEMENTATION AT PRODUCTION COMPANIES

    Directory of Open Access Journals (Sweden)

    Yurii Safonov

    2017-11-01

    Full Text Available The purpose and objectives. Time management is still not a very popular element in many enterprises, while its implementation significantly increases staff productivity and, ultimately, the effectiveness of the company. For this reason, the purpose of the article is to promote time management in a business environment by providing specific tools, principles, methods and systems, and to show its importance to the company and describe the influence of time management for the enterprise. Methods. The study used a generalization, systematization, empirical research, systematic and logical approach to the development of theoretical and methodological provisions for instrumental support management performance of the industrial enterprise. Results. Time management is one of the most important strategic tools of the modern manager. It can help both existing companies and companies that are just launched (the project. Practical implications. The current goal of time management as a mechanism to improve the efficiency of the company. Value/originality. To implement it, the company offered a popular time management system, allowing the company to increase the effectiveness of its activities.

  11. Bio-hydrogen production based on catalytic reforming of volatiles generated by cellulose pyrolysis: An integrated process for ZnO reduction and zinc nanostructures fabrication

    International Nuclear Information System (INIS)

    Maciel, Adriana Veloso; Job, Aldo Eloizo; Nova Mussel, Wagner da; Brito, Walter de; Duarte Pasa, Vanya Marcia

    2011-01-01

    The paper presents a process of cellulose thermal degradation with bio-hydrogen generation and zinc nanostructures synthesis. Production of zinc nanowires and zinc nanoflowers was performed by a novel processes based on cellulose pyrolysis, volatiles reforming and direct reduction of ZnO. The bio-hydrogen generated in situ promoted the ZnO reduction with Zn nanostructures formation by vapor-solid (VS) route. The cellulose and cellulose/ZnO samples were characterized by thermal analyses (TG/DTG/DTA) and the gases evolved were analyzed by FTIR spectroscopy (TG/FTIR). The hydrogen was detected by TPR (Temperature Programmed Reaction) tests. The results showed that in the presence of ZnO the cellulose thermal degradation produced larger amounts of H 2 when compared to pure cellulose. The process was also carried out in a tubular furnace with N 2 atmosphere, at temperatures up to 900 o C, and different heating rates. The nanostructures growth was catalyst-free, without pressure reduction, at temperatures lower than those required in the carbothermal reduction of ZnO with fossil carbon. The nanostructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The optical properties were investigated by photoluminescence (PL). One mechanism was presented in an attempt to explain the synthesis of zinc nanostructures that are crystalline, were obtained without significant re-oxidation and whose morphologies are dependent on the heating rates of the process. This route presents a potential use as an industrial process taking into account the simple operational conditions, the low costs of cellulose and the importance of bio-hydrogen and nanostructured zinc.

  12. Nitrous Oxide and Nitrous Oxide-Free Low-Flow Anesthesia Using Bispectral Index Monitoring: Effects on Hemodynamics, Recovery Times, Volatile Anesthetic Consumption and Costs

    Directory of Open Access Journals (Sweden)

    Bengü Gülhan Köksal

    2010-12-01

    Full Text Available Aim: In this study, we aimed to compare the effects of desfluraneN2O and desflurane-fentanyl combinations on hemodynamics, recovery times, volatile anesthetic consumption and costs in low-flow desflurane anesthesia by bispectral index (BIS monitoring of depth of anesthesia. Methods: After approval of ethics committee and obtaining patient consents, 60 patients were divided into two equal groups randomly. Non-invasive blood pressure measurement, ECG, SpO2 and BIS were monitored. All patients received 10 L .min-1 100% oxygen with mask for 5 minute before intubation. 2 mg.kg-1 propofol, 2 μg.kg-1 fentanyl and 0.6 mg.kg-1 rocuronium bromide were administered at induction in both groups. Desfluran 6% was chosen for anesthesia maintenance. Group 1 received 50% O2-N2O mixture in 6 L.min-1 and Group 2 received 50% O2-air mixture in 6 L.min-1 as carrier gas. Low-flow anesthesia (1 L.min-1 was started after a 10-min period of initial high flow (6 L.min-1. In Group 2, infusion of fentanyl was begun in 1 μg.kg.hour-1 rate. Desflurane level was adjusted at a main BIS value of 40-60. Blood pressure, heart rate, FiO2, etO2, FiN22, EtN2O, FiCO2, EtCO2, Fidesfluran and Etdesflurane were recorded. Results: There were no significant differences between the two groups in terms of heart rate, arterial blood pressure, settings of desfluran and recovery time. BIS values (p<0.001 and anesthetic agent costs (p<0.001 were higher in Group 2. Conclusion: Using fentanyl infusion instead of nitrous oxide in low flow-anesthesia with desflurane did not alter the hemodynamic parameters. Fentanyl infusion with medical air-oxygen as carrier gas is an alternative technique, but increases BIS values and anesthetic agent costs. (The Medical Bulletin of Haseki 2010; 48: 132-8

  13. Method for Hot Real-Time Sampling of Gasification Products

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-29

    The Thermochemical Process Development Unit (TCPDU) at the National Renewable Energy Laboratory (NREL) is a highly instrumented half-ton/day pilot scale plant capable of demonstrating industrially relevant thermochemical technologies from lignocellulosic biomass conversion, including gasification. Gasification creates primarily Syngas (a mixture of Hydrogen and Carbon Monoxide) that can be utilized with synthesis catalysts to form transportation fuels and other valuable chemicals. Biomass derived gasification products are a very complex mixture of chemical components that typically contain Sulfur and Nitrogen species that can act as catalysis poisons for tar reforming and synthesis catalysts. Real-time hot online sampling techniques, such as Molecular Beam Mass Spectrometry (MBMS), and Gas Chromatographs with Sulfur and Nitrogen specific detectors can provide real-time analysis providing operational indicators for performance. Sampling typically requires coated sampling lines to minimize trace sulfur interactions with steel surfaces. Other materials used inline have also shown conversion of sulfur species into new components and must be minimized. Sample line Residence time within the sampling lines must also be kept to a minimum to reduce further reaction chemistries. Solids from ash and char contribute to plugging and must be filtered at temperature. Experience at NREL has shown several key factors to consider when designing and installing an analytical sampling system for biomass gasification products. They include minimizing sampling distance, effective filtering as close to source as possible, proper line sizing, proper line materials or coatings, even heating of all components, minimizing pressure drops, and additional filtering or traps after pressure drops.

  14. Influence of the yeast autolysates addition on the volatile compounds of sparkling white wines

    Directory of Open Access Journals (Sweden)

    Pérez-Magariño Silvia

    2014-01-01

    Full Text Available During sparkling wine aging, different compounds such as polysaccharides can be released due to yeast autolysis that can cause important changes in wine composition. Yeast autolysis is a slow natural process that takes long time, and the addition of some products could improve the quality of these wines. The aim of this work was to study the effect of the addition of several commercial yeast autolysates on the volatile composition of white sparkling wines (Godello and Verdejo, and aged on lees for 9 months. The discriminant analyses indicated that the sparkling wines treated with PCP2 showed the highest differences in the volatile composition of both sparkling wines studied, being the ethyl esters, terpenes, decanoic acid and some alcohols, the compounds that were affected in a greater extent. This fact could be due to PCP2 presenting the highest mannoprotein percentage that can interact with volatile compounds, modulating their volatility and perception.

  15. Volatile fatty acids (VFAs) production from swine manure through short-term dry anaerobic digestion and its separation from nitrogen and phosphorus resources in the digestate.

    Science.gov (United States)

    Huang, Weiwei; Huang, Wenli; Yuan, Tian; Zhao, Ziwen; Cai, Wei; Zhang, Zhenya; Lei, Zhongfang; Feng, Chuanping

    2016-03-01

    The sustainability of an agricultural system depends highly upon the recycling of all useful substances from agricultural wastes. This study explored the feasibility of comprehensive utilization of C, N and P resources in swine manure (SM) through short-term dry anaerobic digestion (AD) followed by dry ammonia stripping, aiming at achieving (1) effective total volatile fatty acids (VFAs) production and separation; (2) ammonia recovery from the digestate; and (3) preservation of high P bioavailability in the solid residue for further applications. Specifically, two ammonia stripping strategies were applied and compared in this work: (I) ammonia stripping was directly performed with the digestate from dry AD of SM (i.e. dry ammonia stripping); and (II) wet ammonia stripping was conducted by using the resultant filtrate from solid-liquid separation of the mixture of digestate and added water. Results showed that dry AD of the tested SM at 55 °C, 20% TS and unadjusted initial pH (8.6) for 8 days produced relatively high concentrations of total VFAs (94.4 mg-COD/g-VS) and ammonia-N (20.0 mg/g-VS) with high potentially bioavailable P (10.6 mg/g-TS) remained in the digestate, which was considered optimal in this study. In addition, high ammonia removal efficiencies of 96.2% and 99.7% were achieved through 3 h' dry and wet stripping (at 55 °C and initial pH 11.0), respectively, while the total VFAs concentration in the digestate/filtrate remained favorably unchanged. All experimental data from the two stripping processes well fitted to the pseudo first-order kinetic model (R(2) = 0.9916-0.9997) with comparable theoretical maximum ammonia removal efficiencies (Aeq, >90%) being obtained under the tested dry and wet stripping conditions, implying that the former was more advantageous due to its much higher volumetric total ammonia-N removal rate thus much smaller reactor volume, less energy/chemicals consumption and no foaming problems. After 8 days' dry AD and 3

  16. Production of pizza dough with reduced fermentation time

    Directory of Open Access Journals (Sweden)

    Simone Limongi

    2012-12-01

    Full Text Available The aim of this study was to reduce the fermentation time of pizza dough by evaluating the development of the dough during fermentation using a Chopin® rheofermentometer and verifying the influence of time and temperature using a 2² factorial design. The focus was to produce characteristic soft pizza dough with bubbles and crispy edges and soft in the center. These attributes were verified by the Quantitative Descriptive Analysis (QDA. The dough was prepared with the usual ingredients, fermented at a temperature range from 27 to 33 ºC for 30 to 42 minutes, enlarged, added with tomato sauce, baked, and frozen. The influence of the variables time and temperature on the release of carbon dioxide (H'm was confirmed with positive and significant effect, using a rheofermentometer, which was not observed for the development or maximum height of the dough (Hm. The same fermentation conditions of the experimental design were used for the production of the pizza dough in the industrial process; it was submitted to Quantitative Descriptive Analysis (QDA, in which the samples were described by nine attributes. The results showed that some samples had the desired characteristics of pizza dough, demonstrated by the principal component analysis (PCA, indicating a 30 % fermentation time reduction when compared to the conventional process.

  17. Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV

    International Nuclear Information System (INIS)

    Tall, Y.

    2008-03-01

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

  18. 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.

  19. Productivity analysis to overcome the limited availability of production time in SME FBS

    Science.gov (United States)

    Nurhasanah, N.; Jingga; Aribowo, B.; Gayatri, AM; Mardhika, DA; Tanjung, WN; Suri, QA; Safitri, R.; Supriyanto, A.

    2017-12-01

    Good industrial development should pay attention to the human factor as the main driver. Condition of work procedures, work area, and environment can affect the production result because if not optimal, the production will run slowly. If the work system is less than optimal, the productivity will do so, the operator will work uncomfortably and be easy to undergo work fatigue, even it can cause work accidents. Thus, the optimal and ergonomic arrangement of the the overall work system mechanism and work environment design is required for workers to work well, regularly, safely and comfortably with the aim of improving work productivity. This research measures the performance in textile SME (Small and Medium Enterprise) located in Sukabumi which is SME FBS which produces children’s clothing. This performance measurement is aimed at improving the competitiveness of the textile IKM so that it has the equal competitiveness with other SMEs or with textile industries that already have their name in market. Based on the method of hour standard time and TOC calculation at 2 FBS CMT (Cut-Make-Trim) in Sukabumi, which are the CMT Margaluyu Village and CMT Purabaya Village, the result is that the standard time of shirt work on CMT Margaluyu Village is less than that of CMT Desa Purabaya. It can be seen that more effective in SME FBS production is by process method.

  20. Assimilation of LAI time-series in crop production models

    Science.gov (United States)

    Kooistra, Lammert; Rijk, Bert; Nannes, Louis

    2014-05-01

    Agriculture is worldwide a large consumer of freshwater, nutrients and land. Spatial explicit agricultural management activities (e.g., fertilization, irrigation) could significantly improve efficiency in resource use. In previous studies and operational applications, remote sensing has shown to be a powerful method for spatio-temporal monitoring of actual crop status. As a next step, yield forecasting by assimilating remote sensing based plant variables in crop production models would improve agricultural decision support both at the farm and field level. In this study we investigated the potential of remote sensing based Leaf Area Index (LAI) time-series assimilated in the crop production model LINTUL to improve yield forecasting at field level. The effect of assimilation method and amount of assimilated observations was evaluated. The LINTUL-3 crop production model was calibrated and validated for a potato crop on two experimental fields in the south of the Netherlands. A range of data sources (e.g., in-situ soil moisture and weather sensors, destructive crop measurements) was used for calibration of the model for the experimental field in 2010. LAI from cropscan field radiometer measurements and actual LAI measured with the LAI-2000 instrument were used as input for the LAI time-series. The LAI time-series were assimilated in the LINTUL model and validated for a second experimental field on which potatoes were grown in 2011. Yield in 2011 was simulated with an R2 of 0.82 when compared with field measured yield. Furthermore, we analysed the potential of assimilation of LAI into the LINTUL-3 model through the 'updating' assimilation technique. The deviation between measured and simulated yield decreased from 9371 kg/ha to 8729 kg/ha when assimilating weekly LAI measurements in the LINTUL model over the season of 2011. LINTUL-3 furthermore shows the main growth reducing factors, which are useful for farm decision support. The combination of crop models and sensor

  1. Implementation of Releasing Time to Care - the productive ward.

    Science.gov (United States)

    Wilson, Gwyneth

    2009-07-01

    This paper describes the implementation of the NHS Institute for Innovation and Improvement Productive Ward - releasing time to care programme. It will discuss the benefits and key successes and provides advice for those wishing to implement the programme. In Lord Darzi's Next Stage Review, he advocates an ambitious vision of patient centred - clinician led, locally driven NHS. The Releasing Time to Care programme is a unique opportunity for everyone working within the NHS to improve effectiveness, safety and reliability of the services we provide. Whilst being situated within a National Health Service policy environment learning from this work can be translated nationally and internationally, as the principles underpin the provision of high quality care. Evaluation is currently in relation to each of the 15 modules rather than as the programme as a whole. It uses various methods including audit, observation, activity follow through, satisfaction surveys and process mapping. Each month data is colated for each of the 11 metrics which has shown a reduction in falls, drug administration errors and improvement in the recording of patient observations. One of the key issues is that an essential component for the success of the programme lies in the tangible support of the Trust Board/Board of Directors. Evidence shows that this programme improves patient satisfaction as it enables the provision of an increase in direct patient care by staff and subsequently improved clinical and safety outcomes. Ward Sister/Charge Nurse development includes Leadership, Project management and Lean Methodology techniques. The Releasing Time to Care programme is a key component of the Next Stage Review. It will create productive organisations by being a catalyst for the transformation of Trust services, enabling staff to spend more time caring for patients and users. This release in time will result in better outcomes and subsequent improvement with patient and staff satisfaction and

  2. Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV; Mesures de taux de production d'elements gazeux et volatiles lors de reactions induites par des protons de 1 et 1,4 GeV sur des cibles epaisses de plomb et plomb-bismuth liquides

    Energy Technology Data Exchange (ETDEWEB)

    Tall, Y

    2008-03-15

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

  3. Flower volatiles, crop varieties and bee responses.

    Directory of Open Access Journals (Sweden)

    Björn K Klatt

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

  4. Exploring Mediating and Moderating Influences on the Links between Cycle Time, Proficiency in Entry Timing and New Product Profitability

    NARCIS (Netherlands)

    Langerak, F.; Hultink, E.J.; Griffin, A.

    2006-01-01

    Development cycle time is the elapsed time from the beginning of idea generation to the moment that the new product is ready for market introduction. Market entry timing is contingent upon the new product’s cycle time. Only when the product is completed can a firm decide whether and when to enter

  5. Volatilization of multicomponent mixtures in soil vapor extraction applications

    International Nuclear Information System (INIS)

    Bass, D.H.

    1995-01-01

    In soil vapor extraction (SVE) applications involving multicomponent mixtures, prediction of mass removal by volatilization as a function remediation extent is required to estimate remediation time and to size offgas treatment equipment. SVE is a commonly used remediation technology which volatilizes and enhances aerobic biodegradation of contamination adsorbed to vadose zone soils. SVE is often applied at sites contaminated with petroleum products, which are usually mixtures of many different compounds with vapor pressures spanning several orders of magnitude. The most volatile components are removed first, so the vapor pressure of the remaining contaminant continually decreases over the course of the remediation. A method for assessing how vapor pressure, and hence the rate of volatilization, of a multicomponent mixture changes over the course of a vapor extraction remedy has been developed. Each component is listed, alone, with its mass fraction in the mixture, in decreasing order of pure component vapor pressure (where component analyses are unavailable, model compounds can be used), For most petroleum distillates, the vapor pressure for each component plotted against the cumulative mass fraction of the component in the mixture on semilog coordinates will produce a straight line with a high correlation coefficient. This regression can be integrated to produce an expression for vapor pressure of the overall mixture as a function of extent or remediation

  6. Ultrasonic sludge disintegration for enhanced methane production in anaerobic digestion: effects of sludge hydrolysis efficiency and hydraulic retention time.

    Science.gov (United States)

    Kim, Dong-Jin; Lee, Jonghak

    2012-01-01

    Hydrolysis of waste activated sludge (WAS) has been regarded as the rate limiting step of anaerobic sludge digestion. Therefore, in this study, the effect of ultrasound and hydraulic residence time during sludge hydrolysis was investigated with the goal of enhancing methane production from anaerobic digestion (AD). WAS was ultrasonically disintegrated for hydrolysis, and it was semi-continuously fed to an anaerobic digesters at various hydraulic retention times (HRTs). The results of these experiments showed that the solids and chemical oxygen demand (COD) removal efficiencies when using ultrasonically disintegrated sludge were higher during AD than the control sludge. The longer the HRT, the higher the removal efficiencies of solids and COD, while methane production increased with lower HRT. Sludge with 30% hydrolysis produced 7 × more methane production than the control sludge. The highest methane yields were 0.350 m(3)/kg volatile solids (VS)(add) and 0.301 m(3)/kg COD(con) for 16 and 30% hydrolyzed sludge, respectively. In addition, we found that excess ultrasound irradiation may inhibit AD since the 50% hydrolyzed sludge produced lower methane yields than 16 and 30% hydrolyzed sludge.

  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. Time-dependent histamine release from stored human blood products

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Edvardsen, L; Vangsgaard, K

    1996-01-01

    storage. Whole blood (six units), plasma-reduced whole blood (six units), and plasma- and buffy coat-reduced (saline-adenine-glucose-mannitol) (SAGM) blood (six units) from unpaid healthy donors were stored in the blood bank for 35 days at 4 degrees C. Plasma histamine and total cell-bound histamine......Perioperative transfusion of whole blood has been shown to amplify trauma-induced immunosuppression, which could be attenuated by perioperative administration of histamine2 receptor antagonists. Supernatants from different blood products were, therefore, analysed for histamine content during.......0 (range 176.0-910.0) nmol/l in whole blood and 475.0 (range 360.0-1560.0) nmol/l in plasma-reduced whole blood, while it was undetectable in SAGM blood. Spontaneous histamine release increased in a time-dependent manner from a median of 6.7 (range 2.2-17.4) nmol/l at the time of storage to 175.0 (range 33...

  10. Silo-stored pistachios at varying humidity levels produce distinct volatile biomarkers

    Science.gov (United States)

    Aflatoxin contamination in California tree nuts results in millions of dollars of lost product annually. The current method for detection of aflatoxin is destructive, expensive and time-intensive. Previous studies have demonstrated that volatile profiles of fungal-contaminated tissues are different ...

  11. Electricity market price volatility: The case of Ontario

    International Nuclear Information System (INIS)

    Zareipour, Hamidreza; Bhattacharya, Kankar; Canizares, Claudio A.

    2007-01-01

    Price volatility analysis has been reported in the literature for most competitive electricity markets around the world. However, no studies have been published yet that quantify price volatility in the Ontario electricity market, which is the focus of the present paper. In this paper, a comparative volatility analysis is conducted for the Ontario market and its neighboring electricity markets. Volatility indices are developed based on historical volatility and price velocity concepts, previously applied to other electricity market prices, and employed in the present work. The analysis is carried out in two scenarios: in the first scenario, the volatility indices are determined for the entire price time series. In the second scenario, the price time series are broken up into 24 time series for each of the 24 h and volatility indices are calculated for each specific hour separately. The volatility indices are also applied to the locational marginal prices of several pricing points in the New England, New York, and PJM electricity markets. The outcomes reveal that price volatility is significantly higher in Ontario than the three studied neighboring electricity markets. Furthermore, comparison of the results of this study with similar findings previously published for 15 other electricity markets demonstrates that the Ontario electricity market is one of the most volatile electricity markets world-wide. This high volatility is argued to be associated with the fact that Ontario is a single-settlement, real-time market

  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. New product development projects evaluation under time uncertainty

    Directory of Open Access Journals (Sweden)

    Thiago Augusto de Oliveira Silva

    2009-12-01

    Full Text Available The development time is one of the key factors that contribute to the new product development success. In spite of that, the impact of the time uncertainty on the development has been not fully exploited, as far as decision supporting models to evaluate this kind of projects is concerned. In this context, the objective of the present paper is to evaluate the development process of new technologies under time uncertainty. We introduce a model which captures this source of uncertainty and develop an algorithm to evaluate projects that incorporates Monte Carlo Simulation and Dynamic Programming. The novelty in our approach is to thoroughly blend the stochastic time with a formal approach to the problem, which preserves the Markov property. We base our model on the distinction between the decision epoch and the stochastic time. We discuss and illustrate the applicability of our model through an empirical example.O tempo de desenvolvimento é um dos fatores-chave que contribuem para o sucesso do desenvolvimento de novos produtos. Apesar disso, o impacto da incerteza de tempo no desenvolvimento tem sido pouco considerado em modelos de avaliação e valoração deste tipo de projetos. Neste contexto, este trabalho tem como objetivo avaliar projetos de desenvolvimento de novas tecnologias mediante o tempo incerto. Introduzimos um modelo capaz de captar esta fonte de incerteza e desenvolvemos um algoritmo para a valoração do projeto que integra Simulação de Monte Carlo e Programação Dinâmica. A novidade neste trabalho é conseguir integrar meticulosamente o tempo estocástico a uma estrutura formal para tomada de decisão que preserva a propriedade de Markov. O principal ponto para viabilizar este fato é distinção entre o momento de revisão e o tempo estocástico. Ilustramos e discutimos a aplicabilidade deste modelo por meio de um exemplo empírico.

  14. Range-based volatility, expected stock returns, and the low volatility anomaly

    Science.gov (United States)

    2017-01-01

    One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility), which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics. PMID:29190652

  15. Range-based volatility, expected stock returns, and the low volatility anomaly.

    Science.gov (United States)

    Blau, Benjamin M; Whitby, Ryan J

    2017-01-01

    One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility), which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics.

  16. Range-based volatility, expected stock returns, and the low volatility anomaly.

    Directory of Open Access Journals (Sweden)

    Benjamin M Blau

    Full Text Available One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility, which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics.

  17. 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

  18. Modelling of volatility in monetary transmission mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Dobešová, Anna; Klepáč, Václav; Kolman, Pavel [Department of Statistics and Operation Analysis, Faculty of Business and Economics, Mendel University in Brno, Zemědělská 1, 61300, Brno (Czech Republic); Bednářová, Petra [Institute of Technology and Business, Okružní 517/10, 370 01, České Budějovice (Czech Republic)

    2015-03-10

    The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches.

  19. Modelling of volatility in monetary transmission mechanism

    International Nuclear Information System (INIS)

    Dobešová, Anna; Klepáč, Václav; Kolman, Pavel; Bednářová, Petra

    2015-01-01

    The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches

  20. Volatility Forecast in Crises and Expansions

    Directory of Open Access Journals (Sweden)

    Sergii Pypko

    2015-08-01

    Full Text Available We build a discrete-time non-linear model for volatility forecasting purposes. This model belongs to the class of threshold-autoregressive models, where changes in regimes are governed by past returns. The ability to capture changes in volatility regimes and using more accurate volatility measures allow outperforming other benchmark models, such as linear heterogeneous autoregressive model and GARCH specifications. Finally, we show how to derive closed-form expression for multiple-step-ahead forecasting by exploiting information about the conditional distribution of returns.

  1. Phosphine and methylphosphine production by simulated lightning - s study for the volatile phosphorus cycle and cloud formation in the earth atmosphere

    OpenAIRE

    Glindemann, D.; Edwards, M.; Schrems, Otto

    2004-01-01

    Phosphine (PH3), was recently found worldwide even in the remote atmosphere (Naturwissenschaften 83 (1996a,131, Atmos. Environ. 37 (2003) 2429). It is of interest to find natural mechanisms which could produce phosphine gas and drive a volatile link of the atmospheric phosphorus cycle and the formation of phosphoric acid as possible condensation nuclei for clouds.Here we report on simulated lightning exposing sodium phosphate in a reducing medium (methane model atmosphere or organic matter) f...

  2. 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.

  3. Volatile flavor compounds in yogurt: a review.

    Science.gov (United States)

    Cheng, Hefa

    2010-11-01

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

  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. Volatile products controlling Titan's tholins production

    KAUST Repository

    Carrasco, Nathalie; Gautier, Thomas N.; Es-sebbar, Et-touhami; Pernot, Pascal; Cernogora, Guy

    2012-01-01

    present a complementary study on the same reactor using an in situ diagnostic of the gas phase composition. Various initial N 2/CH 4 gas mixtures (methane varying from 1% to 10%) are studied, with a monitoring of the methane consumption and of the stable

  6. Pricing and Timing Strategies for New Product Using Agent-Based Simulation of Behavioural Consumers

    OpenAIRE

    Keeheon Lee; Hoyeop Lee; Chang Ouk Kim

    2014-01-01

    In this study, we are interested in the problem of determining the pricing and timing strategies of a new product by developing an agent-based product diffusion simulation. In the proposed simulation model, agents imitate behavioural consumers, who are reference dependent and risk averse in the evaluation of new products and whose interactions create word-of-mouth regarding new products. Pricing and timing strategies involve the timing of a new product release, the timing of providing a disco...

  7. Ammonia volatilization from sows on grassland

    Science.gov (United States)

    Sommer, S. G.; Søgaard, H. T.; Møller, H. B.; Morsing, S.

    According to regulations, sows with piglets on organic farms must graze on pastures. Volatilization of ammonia (NH 3) from urine patches may represent a significant source of nitrogen (N) loss from these farms. Inputs of N are low on organic farms and losses may reduce crop production. This study examined spatial variations in NH 3 volatilization using a movable dynamic chamber, and the pH and total ammoniacal nitrogen (TAN) content in the topsoil of pastures with grazing sows was measured during five periods between June 1998 and May 1999. Gross NH 3 volatilization from the pastures was also measured with an atmospheric mass balance technique during seven periods from September 1997 until June 1999. The dynamic chamber study showed a high variation in NH 3 volatilization because of the distribution of urine; losses were between 0 and 2.8 g NH 3-N m -2 day -1. Volatilization was highest near the feeding area and the huts, where the sows tended to urinate. Ammonia volatilization rate was linearly related to the product of NH 3 concentration in the boundary layer and wind speed. The NH 3 in the boundary layer was in equilibrium with NH 3 in soil solution. Gross NH 3 volatilization was in the range 0.07-2.1 kg NH 3-N ha -1 day -1 from a pasture with 24 sows ha -1. Ammonia volatilization was related to the amount of feed given to the sows, incident solar radiation and air temperature during measuring periods, and also to temperature, incident solar radiation and rain 1-2 days before measurements. Annual ammonia loss was 4.8 kg NH 3-N sow -1.

  8. Avaliação do uso de inibidores de etileno sobre a produção de compostos voláteis e de mangiferina em manga Evaluation of the use of ethylene inhibitors on production of volatile compounds and mangiferin in mango fruit

    Directory of Open Access Journals (Sweden)

    Kirley Marques Canuto

    2010-01-01

    Full Text Available Effects of two ethylene inhibitors, 1-methylcylopropene (1-MCP and aminoethoxyvinylglycine (AVG, on production of volatile compounds and mangiferin (a bioactive xanthone in 'Tommy Atkins' mango fruit were investigated. Volatile composition and mangiferin content, in treated and untreated fruits at three maturity, stages were determined by SPME-GC-MS and HPLC, respectively. These chromatographical analysis revealed that the volatile profiles and mangiferin concentrations were not significantly different, suggesting that the use of ethylene inhibitors does not affect the mango aroma and functional properties relative to this xanthone. Moreover, a simple, precise and accurate HPLC method was developed for quantifying mangiferin in mango pulp.

  9. Studies regarding the influence of different straw-based ration types on fermentation and production of volatile fatty acids in the rumen of lactating cows. 1

    International Nuclear Information System (INIS)

    Muenchow, H.; Bergner, H.

    1977-01-01

    Lactating cows fed different types of ration were used to test a combined in-vitro/in-vivo technique for determining the rate of VFA-production. Both under N 2 - and CO 2 -atmosphere the applied in-vitro technique allowed to obtain fermentation results agreeing with the corresponding in-vivo results. The VFA-production was found to depend on the time of rumen juice extraction; it reached its peak 3 hours feed intake. The time-conditioned variations revealed a good agreement between the results obtained before morning and evening feedings, respectively. The rumen juice volume necessary for calculating the daily VFA production rate was recorded using the water-soluble complex of 51 Cr-ethylene diaminetetra acetate (EDTA). The results demonstrate that the measured values are of good reproducibility. Rumen juice volumes of 81.7 +- 6 l (ration type: straw pellets + concentrates) and 81.7 +- 4 l (ration type: fodder beet + dried green forage + concentrates) were recorded for the two groups of 10 experimental cows each, given restricted amounts of water and feed. Replication trials conducted 14 days later gave values of 70.7 +- 4 and 81.7 +- 2 l, respectively. (author)

  10. Implied Volatility Surface: Construction Methodologies and Characteristics

    OpenAIRE

    Cristian Homescu

    2011-01-01

    The implied volatility surface (IVS) is a fundamental building block in computational finance. We provide a survey of methodologies for constructing such surfaces. We also discuss various topics which can influence the successful construction of IVS in practice: arbitrage-free conditions in both strike and time, how to perform extrapolation outside the core region, choice of calibrating functional and selection of numerical optimization algorithms, volatility surface dynamics and asymptotics.

  11. Infrared Spectroscopy of Parent Volatiles in Comets: Implications for Astrobiology

    Science.gov (United States)

    DiSanti, Michael A.

    2010-01-01

    Current cometary orbits provide information on their recent dynamical history. However, determining a given comet's formation region from its current dynamical state alone is complicated by radial migration in the proto-planetary disk and by dynamical interactions with the growing giant planets. Because comets reside for long periods of time in the outer Solar System, the ices contained in their nuclei (native ices) retain a relatively well-preserved footprint of when and where they formed, and this in turn can provide clues to conditions in the formation epoch. As a comet approaches the Sun, sublimation of its native ices releases parent volatiles into the coma where they can be measured spectroscopically. The past to - 15 years have seen the advent of infrared spectrometers with high sensitivity between about 2.8 and 5.0 micron, enabling a taxonomy among comets based on abundances of parent volatiles (e.g., H2O, CO, CH4, C2H6, HCN, CH30H, H2CO, NH3). Such molecules are of keen interest to Astrobiology, as they include important pre-biotic species that likely were required for the emergence of life on Earth and perhaps elsewhere. Approximately 20 comets have thus far been characterized, beginning with C/1996 82 (Hyakutake) in 1996. Molecular production rates are established through comparison of observed emission line intensities with those predicted by quantum mechanical fluorescence models. Abundances of parent volatiles (relative to H2O) vary among even the relatively small number of comets sampled, with the most volatile species (CO and CH4) displaying the largest variations. Techniques developed for measuring parent volatile abundances in comets will be discussed, as will possible implications for their formation.

  12. Exchange Rate Volatility and Trade among the Asia Pacific Countries

    Directory of Open Access Journals (Sweden)

    Saang Joon Baak

    2004-06-01

    Full Text Available The purpose of this paper is to investigate the impact of exchange rate volatility on exports among 14 Asia Pacific countries, where various measures to raise the intra-region trade are being implemented. Specifically, this paper estimates a gravity model, in which the dependent variable is the product of the exports of two trading countries. In addition, it also estimates a unilateral exports model, in which the dependent variable is not the product of the exports of two trading countries but the exports from one country to another. By doing this, the depreciation rate of the exporting country's currency value can be included as one of the explanatory variables affecting the volume of exports. As the explanatory variables of the export volume, the gravity model adopts the product of the GDPs of two trading counties, their bilateral exchange rate volatility, their distance, a time trend and dummies for the share of the border line, the use of the same language, and the APEC membership. In the case of the unilateral exports model, the product of the GDPs is replaced by the GDP of the importing country, and the depreciation rate of the exporting country's currency value is dded. In addition, considering that the export volume will also depend on various onditions of the exporting country, dummies for exporting countries are also included as an explanatory variable. The empirical tests, using annual data for the period from 1980 to 2002, detect a significant negative impact of exchange rate volatility on the volume of exports. In addition, various tests using the data for sub-sample periods indicate that the negative impact had been weakened since 1989, when APEC had launched, and surged again from 1997, when the Asian financial crisis broke out. This finding implies that the impact of exchange rate volatility is time-dependent and that it is significantlynegative at least in the present time. This phenomenon is noticed regardless which estimation

  13. 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)

  14. Volatile element loss during planetary magma ocean phases

    Science.gov (United States)

    Dhaliwal, Jasmeet K.; Day, James M. D.; Moynier, Frédéric

    2018-01-01

    Moderately volatile elements (MVE) are key tracers of volatile depletion in planetary bodies. Zinc is an especially useful MVE because of its generally elevated abundances in planetary basalts, relative to other MVE, and limited evidence for mass-dependent isotopic fractionation under high-temperature igneous processes. Compared with terrestrial basalts, which have δ66Zn values (per mille deviation of the 66Zn/64Zn ratio from the JMC-Lyon standard) similar to some chondrite meteorites (∼+0.3‰), lunar mare basalts yield a mean δ66Zn value of +1.4 ± 0.5‰ (2 st. dev.). Furthermore, mare basalts have average Zn concentrations ∼50 times lower than in typical terrestrial basaltic rocks. Late-stage lunar magmatic products, including ferroan anorthosite, Mg- and Alkali-suite rocks have even higher δ66Zn values (+3 to +6‰). Differences in Zn abundance and isotopic compositions between lunar and terrestrial rocks have previously been interpreted to reflect evaporative loss of Zn, either during the Earth-Moon forming Giant Impact, or in a lunar magma ocean (LMO) phase. To explore the mechanisms and processes under which volatile element loss may have occurred during a LMO phase, we developed models of Zn isotopic fractionation that are generally applicable to planetary magma oceans. Our objective was to identify conditions that would yield a δ66Zn signature of ∼+1.4‰ within the lunar mantle. For the sake of simplicity, we neglect possible Zn isotopic fractionation during the Giant Impact, and assumed a starting composition equal to the composition of the present-day terrestrial mantle, assuming both the Earth and Moon had zinc 'consanguinity' following their formation. We developed two models: the first simulates evaporative fractionation of Zn only prior to LMO mixing and crystallization; the second simulates continued evaporative fractionation of Zn that persists until ∼75% LMO crystallization. The first model yields a relatively homogenous bulk solid

  15. 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

  16. Trade Openness And Real Exchange Rate Volatility: Panel Data Evidence

    OpenAIRE

    César Calderón

    2004-01-01

    A recent strand of the literature, the so-called “New Open Economy Macroeconomics”, argues that nonmonetary factors have gained importance in explaining exchange rate volatility. In this context, it has been suggested the inclusion of shocks to productivity, terms of trade, and government spending, among others. The goal of the present paper is to explain the real exchange rate volatility by positing a structural relationship between volatility and its determinants. To perform our task we col...

  17. Real Time Part Input Control of a Pull Production System by Finding IF-THEN Rules

    Science.gov (United States)

    Ramli, Rizauddin; Yamamoto, Hidehiko; Abu Qudeiri, Jaber

    This paper considers the part input problem of a production system where two Flexible Transfer Lines (FTLs) consisting of an up-stream production line and a down-stream production line while operating under Just In Time (JIT) production management. The up-stream production line processes the raw material after receiving them from suppliers, and after processing them, delivers the processed product to a down-stream production line via a conveyer. In this paper, we have proposed a novel idea for a part input real time control system, known as Algorithm for Real Time Control of Part Input Systems (ARTCOPS). The algorithm is useful when FTLs are in operation under a production order that is different from the pre-decided production schedule. Simulations of virtual production systems have been carried out to verify that ARTCOPS is useful in real time control, although the production orders are different from the pre-decided production scheduling.

  18. 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

  19. Volatile Compounds and Lactic Acid Bacteria in Spontaneous Fermented Sourdough

    International Nuclear Information System (INIS)

    Kam, W.Y.; Aida, W.M.W.; Sahilah, A.M.; Maskat, M.Y.

    2011-01-01

    The aim of this study is to identify the predominating lactic acid bacteria (LAB) in a spontaneous fermented wheat sourdough. At the same time, an investigation towards volatile compounds that were produced was also carried out. Lactobacillus plantarum has been identified as the dominant species of lactobacilli with characters of a facultative heterofermentative strain. The generated volatile compounds that were produced during spontaneous fermentation were isolated by solvent extraction method, analysed by gas chromatography (GC), and identified by mass spectrophotometer (MS). Butyric acid has been found to be the main volatile compound with relative abundance of 6.75 % and acetic acid at relative abundance of 3.60 %. Esters that were formed at relatively low amount were butyl formate (1.23 %) and cis 3 hexenyl propionate (0.05 %). Butanol was also found at low amount with relative abundance of 0.60 %. The carbohydrate metabolism of Lactobacillus plantarum may contributed to the production of acetic acid in this study via further catabolism activity on lactic acid that was produced. However, butyric acid was not the major product via fermentation by LAB but mostly carried out by the genus Clostridium via carbohydrate metabolism which needs further investigation. (author)

  20. Volatilization of iodine from soils and plants

    International Nuclear Information System (INIS)

    Wildung, R.E.; Cataldo, D.A.; Garland, T.R.

    1985-04-01

    Elevated levels of 129 I, a long-lived fission product, are present in the environment as a result of nuclear weapons testing and fuel reprocessing. To aid in understanding the anomalous behavior of this element, relative to natural I ( 127 I), in the vicinity of nuclear fuel reprocessing plants, preliminary laboratory-growth chamber studies were undertaken to examine the possible formation of volatile inorganic and organic I species in soil and plant systems. Inorganic 129 I added to soil was volatilized from both the soil and plant during plant growth, at average ratios of 2 x 10 -3 %/day soil and 9 x 10 -3 %/day foliage, respectively. Volatilization rates from soil were an order of magnitude less in the absence of growing roots. Less than 2% of soil or plant volatiles was subsequently retained by plant canopies. Volatile I, chemically characterized by selective sorption methods, consisted principally of alkyl iodides formed by both soil and plant processes. However, plants and soils containing actively growing roots produced a larger fraction of volatile inorganic I than soil alone. 14 refs., 1 fig., 3 tabs