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Sample records for acid gas scrubbing

  1. Process for defoaming acid gas scrubbing solutions and defoaming solutions

    SciTech Connect

    Ernst, E.R.; Robbins, M.L.

    1980-06-17

    The foam in acid gas scrubbing solutions created during an acid gas scrubbing process is reduced or eliminated by the addition of certain polyoxyethylene polyoxypropylene block copolymers as defoaming agents. The defoaming agents are particularly effective when the acid gas scrubbing solution contains an amine having a large hydrophobic moiety.

  2. Acid gas scrubbing by composite solvent-swollen membranes

    DOEpatents

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1988-01-01

    A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorous and sulfur, and having a boiling point of at least 100.degree. C. and a solubility parameter of from about 7.5 to about 13.5 (cal/cm.sup.3 -atm).sup.1/2. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes.

  3. Acid gas scrubbing by composite solvent-swollen membranes

    DOEpatents

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1988-04-12

    A composite immobilized liquid membrane suitable for acid gas scrubbing is disclosed. The membrane is a solvent-swollen polymer and a microporous polymeric support, the solvent being selected from a class of highly polar solvents containing at least one atom selected from nitrogen, oxygen, phosphorus and sulfur, and having a boiling point of at least 100 C and a solubility parameter of from about 7.5 to about 13.5 (cal/cm[sup 3]-atm)[sup 1/2]. Such solvents are homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. Also disclosed are methods of acid gas scrubbing of high- and low-Btu gas effluents with such solvent-swollen membranes. 3 figs.

  4. Magmatic gas scrubbing: Implications for volcano monitoring

    USGS Publications Warehouse

    Symonds, R.B.; Gerlach, T.M.; Reed, M.H.

    2001-01-01

    Despite the abundance of SO2(g) in magmatic gases, precursory increases in magmatic SO2(g) are not always observed prior to volcanic eruption, probably because many terrestrial volcanoes contain abundant groundwater or surface water that scrubs magmatic gases until a dry pathway to the atmosphere is established. To better understand scrubbing and its implications for volcano monitoring, we model thermochemically the reaction of magmatic gases with water. First, we inject a 915??C magmatic gas from Merapi volcano into 25??C air-saturated water (ASW) over a wide range of gas/water mass ratios from 0.0002 to 100 and at a total pressure of 0.1 MPa. Then we model closed-system cooling of the magmatic gas, magmatic gas-ASW mixing at 5.0 MPa, runs with varied temperature and composition of the ASW, a case with a wide range of magmatic-gas compositions, and a reaction of a magmatic gas-ASW mixture with rock. The modeling predicts gas and water compositions, and, in one case, alteration assemblages for a wide range of scrubbing conditions; these results can be compared directly with samples from degassing volcanoes. The modeling suggests that CO2(g) is the main species to monitor when scrubbing exists; another candidate is H2S(g), but it can be affected by reactions with aqueous ferrous iron. In contrast, scrubbing by water will prevent significant SO2(g) and most HCl(g) emissions until dry pathways are established, except for moderate HCl(g) degassing from pH 100 t/d (tons per day) of SO2(g) in addition to CO2(g) and H2S(g) should be taken as a criterion of magma intrusion. Finally, the modeling suggests that the interpretation of gas-ratio data requires a case-by-case evaluation since ratio changes can often be produced by several mechanisms; nevertheless, several gas ratios may provide useful indices for monitoring the drying out of gas pathways. Published by Elsevier Science B.V.

  5. Simultaneous stack gas scrubbing wastewater purification

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Variations of a process for removing sulfur dioxide from stack gases and using it to treat municipal waste water are described. The once-through system lowers the pH of the scrubbing water from minor depressions to a pH of about 2.5 under certain conditions. A recycle system uses iron for catalytic oxidation of sulfurous acid to sulfuric acid allowing very large amounts of sulfur dioxide to be absorbed in a small portion of water. The partial recycle system uses municipal wastewater and iron as a scrubbing medium, followed by neutralization of the wastewater with lime to produce an iron hydroxide precipitation which, when removed, produces tertiary quality treated wastewater. The SO2 scrubber is described, test results are analyzed, and a preliminary capital cost estimate for the three processes is included.

  6. Modelling magmatic gas scrubbing in hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Di Napoli, Rossella; Aiuppa, Alessandro; Valenza, Mariano; Bergsson, Baldur; Ilyinskaya, Evgenia; Pfeffer, Melissa Anne; Rakel Guðjónsdóttir, Sylvía

    2015-04-01

    In volcano-hosted hydrothermal systems, the chemistry of deeply rising magmatic gases is extensively modified by gas-water-rock interactions taking place within the hydrothermal reservoir, and/or at shallow groundwaters conditions. These reactions can scrub reactive, water-soluble species (S, halogens) from the magmatic gas phase, so that their quantitative assessment is central to understanding the chemistry of surface gas manifestations, and brings profound implications to the interpretation of volcanic-hydrothermal unrests. Here, we present the results of numerical simulations of magmatic gas scrubbing, in which the reaction path modelling approach (Helgeson, 1968) is used to reproduce hydrothermal gas-water-rock interactions at both shallow (temperature up to 109°C; low-T model runs) and deep reservoir (temperature range: 150-250 °C; high-T model runs) conditions. The model was built based upon the EQ3/6 software package (Wolery and Daveler, 1992), and consisted into a step by step addition of a high-temperature magmatic gas to an initial meteoric water, in the presence of a dissolving aquifer rock. The model outputted, at each step of gas addition, the chemical composition of a new aqueous solution formed after gas-water-rock interactions; which, upon reaching gas over-pressuring (PgasTOT > Psat(H2O) at run T), is degassed (by single-step degassing) to separate a scrubbed gas phase. As an application of the model results, the model compositions of the separated gases are finally compared with compositions of natural gas emissions from Hekla volcano (T< 100°C) and from Krisuvik geothermal system (T> 100°C), resulting into an excellent agreement. The compositions of the model solutions are also in fair agreement with compositions of natural thermal water samples. We conclude that our EQ3/6-based reaction path simulations offer a realistic representation of gas-water-rock interaction processes occurring underneath active magmatic-hydrothermal systems

  7. Simultaneous stack-gas scrubbing and waste water treatment

    NASA Technical Reports Server (NTRS)

    Poradek, J. C.; Collins, D. D.

    1980-01-01

    Simultaneous treatment of wastewater and S02-laden stack gas make both treatments more efficient and economical. According to results of preliminary tests, solution generated by stack gas scrubbing cycle reduces bacterial content of wastewater. Both processess benefit by sharing concentrations of iron.

  8. Wet scrubbing of biomass producer gas tars using vegetable oil

    NASA Astrophysics Data System (ADS)

    Bhoi, Prakashbhai Ramabhai

    The overall aims of this research study were to generate novel design data and to develop an equilibrium stage-based thermodynamic model of a vegetable oil based wet scrubbing system for the removal of model tar compounds (benzene, toluene and ethylbenzene) found in biomass producer gas. The specific objectives were to design, fabricate and evaluate a vegetable oil based wet scrubbing system and to optimize the design and operating variables; i.e., packed bed height, vegetable oil type, solvent temperature, and solvent flow rate. The experimental wet packed bed scrubbing system includes a liquid distributor specifically designed to distribute a high viscous vegetable oil uniformly and a mixing section, which was designed to generate a desired concentration of tar compounds in a simulated air stream. A method and calibration protocol of gas chromatography/mass spectroscopy was developed to quantify tar compounds. Experimental data were analyzed statistically using analysis of variance (ANOVA) procedure. Statistical analysis showed that both soybean and canola oils are potential solvents, providing comparable removal efficiency of tar compounds. The experimental height equivalent to a theoretical plate (HETP) was determined as 0.11 m for vegetable oil based scrubbing system. Packed bed height and solvent temperature had highly significant effect (p0.05) effect on the removal of model tar compounds. The packing specific constants, Ch and CP,0, for the Billet and Schultes pressure drop correlation were determined as 2.52 and 2.93, respectively. The equilibrium stage based thermodynamic model predicted the removal efficiency of model tar compounds in the range of 1-6%, 1-4% and 1-2% of experimental data for benzene, toluene and ethylbenzene, respectively, for the solvent temperature of 30° C. The NRTL-PR property model and UNIFAC for estimating binary interaction parameters are recommended for modeling absorption of tar compounds in vegetable oils. Bench scale

  9. The e-SCRUB Machine: an 800-kV, 500-kW average power pulsed electron beam generator for flue-gas scrubbing

    NASA Astrophysics Data System (ADS)

    Cooper, James R.; Briggs, Ray; Crewson, Walter F.; Johnson, R. D.; Ratafia-Brown, J. A.; Richardson, W. K.; Rienstra, W. W.; Ballard, Perry G.; Cukr, Jeffrey; Cassel, R. L.; Schlitt, Leland; Genuario, R. D.; Morgan, R. D.; Tripoli, G. A.

    1995-03-01

    This paper gives an overview of electron beam dry scrubbing (EBDS) to remove SOx and NOx from flue gases of coal-fired power plants. It also describes the e-SCRUB program, a program currently underway to commercialize this process with an integrated pulsed electron beam. The electron beam, together with injected water and ammonia, causes chemical reactions which convert the SOx and NOx into commercial grade agricultural fertilizer, a usable byproduct. The e-SCRUB facility is a test bed to demonstrate the feasibility and performance of a repetitive, reliable pulsed electron beam generator operating at average power levels of up to 1 MW. This facility contains the electron beam generator and all the auxiliary and support systems required by the machine, including a computer driven central experiment control system, a 100,000 SCFM flowing dry nitrogen load which simulates the characteristics of a power plant flue, and a 2 MVA dedicated electrical service to power the machine. The e-SCRUB electron beam machine is designed to produce an 800 kV pulsed electron beam with a repetition rate of 667 pps. The energy per pulse deposited into the flue gas is approximately 750 J. The pulsed power system converts the utility power input to a 667 pps, 800 kV pulse train which powers the electron gun. The functional units of the pulsed power system will be discussed in the paper, along with some preliminary experimental results.

  10. Ammonia scrubbing at Cominco's sulphur gas handling plants in Trail, B. C

    SciTech Connect

    Brandsenn, W. )

    1988-01-01

    This report describes the ammonia scrubbing process in the sulphur gas handling plant of Cominco's zinc operations at Trail, B.C. This scrubbing process produces ammonium sulfate fertilizer and, if desired, pure liquid sulphur dioxide. Sulphur deficiency in agricultural soil is becoming a growing concern in many parts of the world. The use of modern fertilizers increases crop yields which removes sulphur from the soil faster than it can be replenished from the atmosphere. Deliberate addition of sulphur to fertilizers is therefore required in many countries. The Cominco process combines the removal of low strength SO{sub 2} from a stackgas, and produces an end product that is the basis of ammonium sulphate fertilizer. The process does not produce any waste products which create disposal problems.

  11. System for removing solids from a used lime or limestone slurry scrubbing liquor in flue gas desulfurization

    SciTech Connect

    Randolph, A.D.

    1981-10-13

    The flue gas desulfurization process using a lime or limestone slurry scrubbing solution produces used liquor containing calcium sulfite or sulfate (Typically gypsum). Precipitated particles are removed by feeding the used scrubbing liquor to an agitated crystallization zone to grow crystals and directing part of the used scrubbing liquor from that zone to a quiescent crystallization zone, in which particles are settled back into the agitated zone. An underflow stream from the agitated zone containing large crystals is combined with an overflow stream from the quiescent zone, which combined stream is clarified with the fines being returned to the scrubber and the large crystals being removed as a waste product. Apparatus for performing the above process in which the agitated and quiescent crystallization zones form part of a single crystallization vessel, and the two zones are separated by a baffle.

  12. Limestone scrubbing for 2000 flue gas desulfurization system. Final report, October 1, 1993--April 1, 1997

    SciTech Connect

    1998-10-16

    As emission limits for sulfur dioxide from utility coal-fired boilers become lower due to increased regulation and environmental concern around the globe, power generating companies require increasingly cost-effective pollution control technology in order to maintain or reduce the cost of electricity to the end user. Limestone based wet flue gas desulfurization, or WFGD, is the preferred sulfur dioxide removal technology for utilities in the US and worldwide. This is a result of its extensive reference list, lower risks, and lower evaluated overall costs. For more than two decades ABB has supplied WFGD systems and currently has greater than 29,000 MWe of scrubbing capacity in operation. Given the industry`s ever-present need for lower costs, ABB funds a continuous research and development program focused on technology advancements that will reduce both capital and operating costs for its customers. As a result of this effort the LS-2 Concept WFGD System was developed through revolutionary design changes in every significant subprocess of conventional WFGD technology. To demonstrate the cumulative effects of all the individual advancements of the LS-2 Concept and to prove the process`s viability and cost-efficiency under representative US power plant conditions, the Limestone Scrubbing for 2000 project was initiated. This report is the final submittal to the Ohio Coal Development Office to document the results of this demonstrate project. The four-phase project execution, from the initial design and procurement through erection and extensive testing, proceeded as scheduled and on budget. The project resulted in a successful reference program that illustrates, in detail, the improved efficiencies and costs of the LS-2 advancements.

  13. Acid gas removal in a confined vortex scrubber

    SciTech Connect

    Hura, H.S.; Diehl, R.C.

    1994-12-31

    This paper reports results of acid gas removal tests performed on a confined vortex scrubber. The confined vortex scrubber (CVS) was developed at the Energy Technology Office of Textron Defense Systems (ETO/TDS) under company as well as Pittsburgh Energy Technology Center (PETC) funding. Previous tests on the CVS have demonstrated > 98% capture for sub-micron fly ash particles, as well as high mercury vapor removal from gas streams. In the recent tests water, sodium hydroxide, and sodium sulfite and bisulfite solutions were used to scrub out hydrochloric, acid gas (HCl) and sulfur dioxide (SO{sub 2}) doped in air supplied to the CVS. The capture efficiency was determined as a function of acid gas concentration, liquor flow rate, and liquor type. When the liquor was supplied only inside the CVS squirrel cage the HCl removal efficiency varied from 85--100% while the SO{sub 2} removal efficiency varied from 60--80%. Significantly higher captures were obtained at 1/3 rd the liquor flow rate by spraying the liquor upstream of the CVS in the air inlet pipe, and increasing the liquor/gas contact time. Total HCl captures > 95% and SO{sub 2} captures > 85% were obtained at a liquid/gas ratio of only 2 gal/1,000 acf for acid gas concentrations of 200--1,800 ppmv. There were no significant differences in the SO{sub 2}, scrubbing ability of the three sodium solutions, and the HCl scrubbing ability of water and a sodium hydroxide solution. These results suggest that the acid gas capture in the CVS is mass transfer limited because of the extremely short gas residence times in the CVS.

  14. Particulate Scrubbing Performance of the High Level Caves Off-Gas System

    SciTech Connect

    Wright, G.T.

    2001-08-16

    Performance tests were conducted at the ETF using off-gas from the Small Cylindrical Melter (SCM) -2. The purpose of these tests was to develop data for comparing small and full scale equipment performance. This reports discusses those test results.

  15. Reversible Acid Gas Capture Using CO2-Binding Organic Liquids

    SciTech Connect

    Heldebrant, David J.; Koech, Phillip K.; Yonker, Clement R.; Rainbolt, James E.; Zheng, Feng

    2010-08-31

    Acid gas scrubbing technology is predominantly aqueous alkanolamine based. Of the acid gases, CO2, H2S and SO2 have been shown to be reversible, however there are serious disadvantages with corrosion and high regeneration costs. The primary scrubbing system composed of monoethanolamine is limited to 30% by weight because of the highly corrosive solution. This gravimetric limitation limits the CO2 volumetric (≤108 g/L) and gravimetric capacity (≤7 wt%) of the system. Furthermore the scrubbing system has a large energy penalty from pumping and heating the excess water required to dissolve the MEA bicarbonate salt. Considering the high specific heat of water (4 j/g-1K-1), low capacities and the high corrosion we set out to design a fully organic solvent that can chemically bind all acid gases i.e. CO2 as reversible alkylcarbonate ionic liquids or analogues thereof. Having a liquid acid gas carrier improves process economics because there is no need for excess solvent to pump and to heat. We have demonstrated illustrated in Figure 1, that CO2-binding organic liquids (CO2BOLs) have a high CO2 solubility paired with a much lower specific heat (<1.5 J/g-1K-1) than aqueous systems. CO2BOLs are a subsection of a larger class of materials known as Binding Organic Liquids (BOLs). Our BOLs have been shown to reversibly bind and release COS, CS2, and SO2, which we denote COSBOLS, CS2BOLs and SO2BOLs. Our BOLs are highly tunable and can be designed for post or pre-combustion gas capture. The design and testing of the next generation zwitterionic CO2BOLs and SO2BOLs are presented.

  16. A Pilot-Scale Evaluation of a New Technology to Control NO(x) Emissions from Boilers at KSC: Hydrogen Peroxide Injection into Boiler Flue Gases Followed by Wet Scrubbing of Acid Gases

    NASA Technical Reports Server (NTRS)

    Cooper, C. David

    1997-01-01

    Emissions of nitrogen oxides NO(x) are a significant problem in the United States. NO(x) are formed in any combustion process, therefore it is not surprising that NO(x) are emitted from the boilers at KSC. Research at UCF has shown (in the laboratory) that injecting H2O2 into hot simulated flue gases can oxidize the NO and NO2 to their acid gas forms, HNO2 and HNO3, respectively. These acid gases are much more water soluble than their counterparts, and theoretically can be removed easily by wet scrubbing. This technology was of interest to NASA, both for their boilers at KSC, and for their combustion sources elsewhere. However, it was necessary to field test the technology and to provide pilot-scale data to aid in design of full-scale facilities. Hence this project was initiated in May of 1996.

  17. Acidic gas capture by diamines

    SciTech Connect

    Rochelle, Gary; Hilliard, Marcus

    2011-05-10

    Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

  18. Studies of the surgical scrub.

    PubMed

    Tucci, V J; Stone, A M; Thompson, C; Isenberg, H D; Wise, L

    1977-09-01

    A study comparing the relative efficacy of a five versus a ten minute surgical scrub was carried out using random sampling of personnel scrubbing for routine scheduled hospital surgical procedures. Scrubbing for five minutes was found to be equally as effective as scrubbing for ten minutes. Betadine was compared to pHisoHex as a scrubbing agent and found to be statistically more effective in degerming the skin following a five minute scrub. As a result of this study, a routine preoperative surgical scrub of five minutes' duration, using Betadine as the scrubbing agent, is recommended.

  19. Effects of Elevated CO2 on Soil Trace Gas (CH4, N2O and NO) Fluxes in a Scrub Oak Ecosystem at Kennedy Space Center, FL, USA

    NASA Astrophysics Data System (ADS)

    Hartley, A. E.; Bracho, R. G.; Stover, D.

    2008-05-01

    Rising atmospheric CO2 concentrations increase the plant demand for soil nutrients, which in turn can impose a nitrogen limitation on unmanaged ecosystems. The microbial responses to CO2 enrichment are complex and difficult to predict. Some studies suggest that CO2 enrichment increases microbial mineralization of nitrogen, making nitrogen more available through a carbon priming effect. Alternatively, microbes may contribute to nitrogen limitation through accelerated soil nitrogen losses. In this study, we examined the effects of CO2 enrichment on trace gases that are released or taken up during soil microbial reactions: nitrification, denitrification and methane consumption. Ambient and approximately twice-ambient CO2 treatments were applied to a coastal scrub oak community at Kennedy Space Center, FL, via open-top chambers since May 1996. The CO2 treatments ended in July 2007 before an aboveground harvest took place inside the chambers. Nitrous oxide (N2O), nitric oxide (NO) and methane (CH4) fluxes were measured in the field from 2006-2008. Soil N2O losses from the study site were low (< 1 ng N2O-N cm-2 h-1) with no CO2 treatment effect. Soil NO losses were similarly low (< 1 ng N2O-N cm-2 h-1), but fluxes were consistently lower in elevated CO2 than in ambient CO2. NO production was higher for 3 months post-harvest in ambient CO2. Methane consumption was lower in elevated vs. ambient CO2 in 2006, although this trend was not significant. Over a decade of CO2 enrichment has reduced soil nitrogen availability, which could explain the low overall rates of nitrogen trace gas emission. Reduced soil carbon stores in elevated CO2 measured at this site could also explain the lower nitrification rates, measured as NO efflux. Trace gas emissions in this sandy, nutrient-poor scrub oak forest are comparable to published rates in desert ecosystems.

  20. Scrubbing liquors for nitrogen tetroxide

    NASA Technical Reports Server (NTRS)

    Thomas, J. J.

    1978-01-01

    Once it was determined that the wet scrubbing concept was the most practical solution to the N2O4 emission problem, it became important to optimize the composition of the scrubbing liquor. Several reagents were cited in the literature as being advantageous in scrubbing NO2. Experiments were conducted on a model wet scrubber in order to verify and rank the performances of these scrubbing liquors. The most efficient scrubbing liquor found experimentally was a 10% sodium sulfite solution.

  1. Influence of cathode on the electro-generation of peroxydisulfuric acid oxidant and its application for effective removal of SO2 by room temperature electro-scrubbing process.

    PubMed

    Balaji, Subramanian; Muthuraman, Govindan; Moon, Il Shik

    2015-12-15

    Peroxydisulfuric acid oxidant (H2S2O8) was electro-generated using boron doped diamond (BDD) anode in an undivided electrolytic cell under the optimized conditions and used for the oxidative removal of gaseous SO2. The influence of the nature of cathode material on the formation yield of H2S2O8 was investigated with Ti, Pt, Zr and DSA electrodes in a flow type electrolytic cell under batch recirculation mode. Among the various cathodes employed Ti exhibited a good performance and the formation yield was nearly doubled (0.19 M) compared to the reported value of 0.07 M. The optimization of electrode area ratio between the anode and cathode brought out the fact that for nearly 8 times smaller Ti cathode (8.75:1) the achieved yield was ∼65% higher than the 1:1 ratio of anode and cathode. The highest concentration of 6.8% (0.48 M) H2S2O8 was seen for 35 cm(2) BDD anode with 4 cm(2) Ti at 20 °C with the measured redox potential value of +1200 mV. The oxidative removal of SO2 in an electro-scrubbing column attached to the online production of peroxydisulfuric acid under the optimized conditions of cell parameters shows that SO2 removal efficiency was nearly 100% for 25 and 50 ppm inlet concentrations and 96% for 100 ppm at the room temperature of 25 °C.

  2. The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations.

    PubMed

    Niksa, Stephen; Fujiwara, Naoki

    2005-07-01

    This article introduces a predictive capability for Hg retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given mercury (Hg) speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO2) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections clearly signal that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO2 absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO2 capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O2 levels and the FGD temperature; weakly dependent on SO2 capture efficiency; and insensitive to HgCl2, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO3 levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg(O) but only for inlet O2 levels that are much lower than those in full-scale FGDs. PMID:16111136

  3. The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations.

    PubMed

    Niksa, Stephen; Fujiwara, Naoki

    2005-07-01

    This article introduces a predictive capability for Hg retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given mercury (Hg) speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO2) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections clearly signal that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO2 absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO2 capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O2 levels and the FGD temperature; weakly dependent on SO2 capture efficiency; and insensitive to HgCl2, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO3 levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg(O) but only for inlet O2 levels that are much lower than those in full-scale FGDs.

  4. The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations

    SciTech Connect

    Stephen Niksa; Naoki Fujiwara

    2005-07-01

    The article introduces a predictive capability for mercury (Hg) retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given Hg speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO{sub 2}) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections show that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO{sub 2} absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO{sub 2} capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O{sub 2} levels and the FGD temperature; weakly dependent on SO{sub 2} capture efficiency; and insensitive to HgCl{sub 2}, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO{sub 3} levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg{sub 0} but only for inlet O{sub 2} levels that are much lower than those in full-scale FGDs. 12 refs., 5 figs., 3 tabs.

  5. Spacecraft surgical scrub system

    NASA Technical Reports Server (NTRS)

    Abbate, M.

    1980-01-01

    Ease of handling and control in zero gravity and minimizing the quantity of water required were prime considerations. The program tasks include the selection of biocidal agent from among the variety used for surgical scrub, formulation of a dispensing system, test, and delivery of flight dispensers. The choice of an iodophore was based on effectiveness on single applications, general familiarity among surgeons, and previous qualification for space use. The delivery system was a choice between the squeeze foamer system and impregnated polyurethane foam pads. The impregnated foam pad was recommended because it is a simpler system since the squeeze foamer requires some applicator to effectively clean the skin surfaces, whereas the form pad is the applicator and agent combined. Testing demonstrated that both systems are effective for use as surgical scrubs.

  6. Scrubbing masks magmatic degassing during repose at Cascade-Range and Aleutian-Arc volcanoes

    USGS Publications Warehouse

    Symonds, Robert B.; Janik, C.J.; Evans, William C.; Ritchie, B.E.; Counce, Dale; Poreda, R.J.; Iven, Mark

    2003-01-01

    Between 1992 and 1998, we sampled gas discharges from ≤173°C fumaroles and springs at 12 quiescent but potentially restless volcanoes in the Cascade Range and Aleutian Arc (CRAA) including Mount Shasta, Mount Hood, Mount St. Helens, Mount Rainier, Mount Baker, Augustine Volcano, Mount Griggs, Trident, Mount Mageik, Aniakchak Crater, Akutan, and Makushin. For each site, we collected and analyzed samples to characterize the chemical (H2O, CO2, H2S, N2, CH4, H2, HCl, HF, NH3, Ar, O2, He) and isotopic (δ13C of CO2, 3He/4He, 40Ar/36Ar, δ34S, δ13C of CH4, δ15N, and δD and δ18O of water) compositions of the gas discharges, and to create baseline data for comparison during future unrest. The chemical and isotopic data show that these gases contain a magmatic component that is heavily modified from scrubbing by deep hydrothermal (150° - 350°C) water (primary scrubbing) and shallow meteoric water (secondary scrubbing). The impact of scrubbing is most pronounced in gas discharges from bubbling springs; gases from boiling-point fumaroles and superheated vents show progressively less impact from scrubbing. The most effective strategies for detecting gas precursors to future CRAA eruptions are to measure periodically the emission rates of CO2 and SO2, which have low and high respective solubilities in water, and to monitor continuously CO2 concentrations in soils around volcanic vents. Timely resampling of fumaroles can augment the geochemical surveillance program by watching for chemical changes associated with drying of fumarolic pathways (all CRAA sites), increases in gas geothermometry temperatures (Mount Mageik, Trident, Mount Baker, Mount Shasta), changes in δ13C of CO2 affiliated with magma movement (all CRAA site), and increases in 3He/4He coupled with intrusion of new magma (Mount Rainier, Augustine Volcano, Makushin, Mount Shasta). Repose magmatic degassing may discharge substantial amounts of S and Cl into the edifices of Mount Baker and several other CRAA

  7. Development of a biphasic electroreactor with a wet scrubbing system for the removal of gaseous benzene.

    PubMed

    Govindan, Muthuraman; Chung, Sang Joon; Moon, Hyun-Ho; Jang, Jae Wook; Moon, Il-Shik

    2013-08-12

    An efficient, continuous flow electroreactor system comprising a scrubbing column (for absorption) and a biphasic electroreactor (for degradation) was developed to treat gas streams containing benzene. Initial benzene absorption studies using a continuous flow bubble column containing absorbents like 40% sulfuric acid, 10% silicone oil (3, 5, 10 cSt), or 100% silicone oil showed that 100% silicone oil is the most suitable. A biphasic batch electroreactor based on 50 mL of silicone oil and 100 mL of activated Co(III) (activated electrochemically) in 40% sulfuric acid demonstrated that indirect oxidation of benzene is possible by Co(III). Combined experiments on the wet scrubbing column and biphasic electroreactor (BP-ER) were performed to determine the feasibility of benzene removal, which is reside in the silicone oil medium. In semidynamic scrubbing with BP-ER experiments using an aqueous electroreactor volume of 2 L, and an inlet gas flow and a gaseous benzene concentration were 10 Lmin(-1) and 100 ppm, respectively, benzene removal efficiency is 75% in sustainable way. The trend of CO2 evolution is well correlated with benzene recovery in the BP-ER. The addition of sodiumdodecyl sulfate (SDS) enhanced the recovery of silicone oil without affecting benzene removal. This process is promising for the treatment of high concentrations of gaseous benzene.

  8. Separation of iodine from mercury containing scrubbing solutions

    DOEpatents

    Burger, Leland L.; Scheele, Randall D.

    1979-01-01

    Radioactive iodines can be recovered from a nitric acid scrub solution containing mercuric nitrate by passing a current through the scrub solution to react the iodine with the mercuric nitrate to form mercuric iodate which precipitates out. The mercuric iodate can then be reacted to recover the radioiodine for further processing into a form suitable for long-term storage and to recover the mercury for recycling.

  9. Evaluation of a technique to measure tropospheric hydroxyl radicals using an aqueous phase salicylic acid scrubbing solution, HPLCseparation and fluorescence detection

    NASA Astrophysics Data System (ADS)

    Salmon, R. A.; Schiller, C. L.; Harris, G. W.

    2003-04-01

    A novel method for monitoring gas phase hydroxyl radicals was examined using a liquid-phase salicylic acid solution to trap tropospheric OH. Quantification occurred following HPLC seperaration and fluorescence detection of one of the products, 2,5-dihydroxy benzoic acid. Although the sensitivity was sufficient to measure typical daytime OH concentrations, the method was hindered by a number of interferences. While most of these were identified and eliminated, an interference from methylperoxy radicals was discovered that could not be removed. The validity of previous reports of OH detection using this method is therefore brought into question.

  10. Scrub typhus meningitis or meningoencephalitis.

    PubMed

    Kim, Dong-Min; Chung, Jong-Hoon; Yun, Na-Ra; Kim, Seok Won; Lee, Jun-Young; Han, Mi Ah; Lee, Yong-Bok

    2013-12-01

    Orientia tsutsugamushi induces vasculitis leading to symptoms of systemic organ invasion including meningitis and meningoencephalitis. We conducted a retrospective case-control study of scrub typhus patients to investigate the clinical and laboratory features of patients with scrub typhus meningitis or meningoencephalitis, and the therapeutic outcomes, and to determine the predictor factors. Cases were 22 patients with scrub typhus meningitis or meningoencephalitis, and controls were 303 patients without meningitis or meningoencephalitis. Multivariate analysis showed that the presence of pneumonitis was associated with the occurrence of scrub typhus meningitis and meningoencephalitis (odds ratio [OR] 8.9; P < 0.001; confidence interval [CI] 2.9-27.2). Although appropriate antimicrobials such as doxycycline agents were administered at an early stage, meningitis or meningoencephalitis still occurred in some cases. Physicians should be aware that meningitis or meningoencephalitis may develop during appropriate drug therapy such as doxycycline. Close observation and great care are essential for patients with risk factors, particularly pneumonitis.

  11. SO2 REMOVAL WITH COAL SCRUBBING

    SciTech Connect

    Eung Ha Cho; Hari Prashanth Sundaram; Aubrey L. Miller

    2001-07-01

    This project is based on an effective removal of sulfur dioxide from flue gas with coal as the scrubbing medium instead of lime, which is used in the conventional FGD processes. A laboratory study proves that coal scrubbing is an innovative technology that can be implemented into a commercial process in place of the conventional lime scrubbing flue gas desulfurization process. SO{sub 2} was removed from a gas stream using an apparatus, which consisted of a 1-liter stirred reactor immersed in a thermostated oil bath. The reactor contained 60 g of 35-65 mesh coal in 600 ml of water. The apparatus also had 2 bubblers connected to the outlet of the reactor, each containing 1500 ml of 1 molar NaOH solution. The flow rate of the gas was 30 ml/sec, temperature was varied from 21 C to 73 C. Oxygen concentration ranged from 3 to 20% while SO{sub 2} concentration, from 500 to 2000 ppm. SO{sub 2} recovery was determined by analyzing SO{sub 2} concentration in the liquid samples taken from the bubblers. The samples taken from the reactor were analyzed for iron concentrations, which were then used to calculate fractions of coal pyrite leached. It was found that SO{sub 2} removal was highly temperature sensitive, giving 13.1% recovery at 21 C and 99.2% recovery at 73 C after 4 hours. The removal of SO{sub 2} was accomplished by the catalysis of iron that was produced by leaching of coal pyrite with combination of SO{sub 2} and O{sub 2}. This leaching reaction was found to be controlled by chemical reaction with apparent activation energy of 11.6 kcal/mole. SO{sub 2} removal increased with increasing O{sub 2} concentration up to 10% and leveled off upon further increase. The effect of SO{sub 2} concentration on its removal was minimal.

  12. Raman Scattering Sensor for On-Line Monitoring of Amines and Acid Gases

    SciTech Connect

    Uibel, Rory; Smith, Lee

    2010-05-20

    Sulfur and CO2 removal from hydrocarbon streams and power plant effluents are a major problem. The sulfur is normally in the form of H2S. These two acid gases are scrubbed using aqueous amine solutions that are difficult to control with conventional technology. Process Instruments Inc. developed Raman scattering technology for on-line, real-time monitoring of amine streams to improve their efficiency in scrubbing H2S and CO2 from hydrocarbon streams and power plant effluents. Improved control of amine and acid gas concentrations will allow refineries, natural gas processes and power plants to more efficiently scrub Sulfur and CO2, saving energy, time and financial resources.

  13. Environmental policy constraints for acidic exhaust gas scrubber discharges from ships.

    PubMed

    Ülpre, H; Eames, I

    2014-11-15

    Increasingly stringent environmental legislation on sulphur oxide emissions from the combustion of fossil fuels onboard ships (International Maritime Organization (IMO) Regulation 14) can be met by either refining the fuel to reduce sulphur content or by scrubbing the exhaust gases. Commonly used open loop marine scrubbers discharge warm acidic exhaust gas wash water into the sea, depressing its pH. The focus on this paper is on the physics and chemistry behind the disposal of acidic discharges in seawater. The IMO Marine Environment Protection Committee (MEPC 59/24/Add.1 Annex 9) requires the wash water to reach a pH greater than 6.5 at a distance of 4m from the point of discharge. We examine the engineering constraints, specifically size and number of ports, to identify the challenges of meeting regulatory compliance. PMID:25284442

  14. Environmental policy constraints for acidic exhaust gas scrubber discharges from ships.

    PubMed

    Ülpre, H; Eames, I

    2014-11-15

    Increasingly stringent environmental legislation on sulphur oxide emissions from the combustion of fossil fuels onboard ships (International Maritime Organization (IMO) Regulation 14) can be met by either refining the fuel to reduce sulphur content or by scrubbing the exhaust gases. Commonly used open loop marine scrubbers discharge warm acidic exhaust gas wash water into the sea, depressing its pH. The focus on this paper is on the physics and chemistry behind the disposal of acidic discharges in seawater. The IMO Marine Environment Protection Committee (MEPC 59/24/Add.1 Annex 9) requires the wash water to reach a pH greater than 6.5 at a distance of 4m from the point of discharge. We examine the engineering constraints, specifically size and number of ports, to identify the challenges of meeting regulatory compliance.

  15. Scrub Typhus Seroprevalence in Healthy Indian Population

    PubMed Central

    Sengupta, Mallika; Anandan, Shalini; Daniel, Dolly

    2015-01-01

    Scrub typhus, a zoonosis caused by Orientia tsutsugamushi, is an important cause of acute febrile illness in India. This preliminary study determines the seroprevalence of scrub typhus in healthy Indian adults by measuring IgM and IgG antibodies to scrub typhus by ELISA in 100 healthy blood donors. Our study demonstrates a 15% seroprevalence of scrub typhus in adults. Further studies are needed to confirm these findings especially in children. PMID:26557523

  16. Carbon Capture by a Continuous, Regenerative Ammonia-Based Scrubbing Process

    SciTech Connect

    Resnik, K.P.; Yeh, J.T.; Pennline, H.W.

    2006-10-01

    Overview: To develop a knowledge/data base to determine whether an ammonia-based scrubbing process is a viable regenerable-capture technique that can simultaneously remove carbon dioxide, sulfur dioxide, nitric oxides, and trace pollutants from flue gas.

  17. Destruction of acid gas emissions

    SciTech Connect

    Mathur, M.P.; Fu, Yuan C.; Ekmann, J.M.; Boyle, J.M.

    1990-12-31

    A method of destroying NO{sub x} and SO{sub x} in a combustion gas is disclosed. The method includes generating active species by treating stable molecules in a high temperature plasma. Ammonia, methane, steam, hydrogen, nitrogen or a combustion of these gases can be selected as the stable molecules. The gases are subjected to plasma conditions sufficient to create free radicals, ions or excited atoms such as N, NH, NH{sub 2}, OH, CH and/or CH{sub 2}. These active species are injected into a combustion gas at a location of sufficiently high temperature to maintain the species in active state and permit them to react with NO{sub x} and SO{sub x}. Typically the injection is made into the immediate post-combustion gases at temperatures of 475--950{degrees}C. 1 fig.

  18. Destruction of acid gas emissions

    DOEpatents

    Mathur, Mahendra P.; Fu, Yuan C.; Ekmann, James M.; Boyle, John M.

    1991-01-01

    A method of destroying NO.sub.x and SO.sub.2 in a combustion gas in disclosed. The method includes generating active species by treating stable moleucles in a high temperature plasma. Ammonia, methane, steam, hydrogen, nitrogen or a combination of these gases can be selected as the stable molecules. The gases are subjected to plasma conditions sufficient to create free radicals, ions or excited atoms such as N, NH, NH.sub.2, OH.sup.-, CH and/or CH.sub.2. These active species are injected into a combustion gas at a location of sufficiently high temperature to maintain the species in active state and permit them to react with NO.sub.x and SO.sub.2. Typically the injection is made into the immediate post-combustion gases at temperatures of 475.degree.-950.degree. C.

  19. System of treating flue gas

    DOEpatents

    Ziegler, D.L.

    1975-12-01

    A system is described for treating or cleaning incinerator flue gas containing acid gases and radioactive and fissionable contaminants. Flue gas and a quench solution are fed into a venturi and then tangentially into the lower portion of a receptacle for restricting volumetric content of the solution. The upper portion of the receptacle contains a scrub bed to further treat or clean the flue gas.

  20. Gas phase acidity of substituted benzenes

    NASA Astrophysics Data System (ADS)

    Bouchoux, Guy

    2011-04-01

    Deprotonation thermochemistry of benzene derivatives C 6H 5X (X = H, F, Cl, OH, NH 2, CN, CHO, NO 2, CH 3, C 2H 5, CHCH 2, CCH) has been examined at the G3B3 level of theory. For X = F, Cl, CN, CHO and NO 2, the most favorable deprotonation site is the ortho position of the phenyl ring. This regio-specificity is directly related to the field/inductive effect of the substituent. G3B3 gas phase acidities, Δ acidH° and Δ acidG°, compare within less than 4 kJ mol -1 with experimental data. A noticeable exception is nitrobenzene for which tabulated acidity appear to be underestimated by ca. 120 kJ mol -1.

  1. Scrubbing noise of externally blown flaps

    NASA Technical Reports Server (NTRS)

    Fink, M. R.

    1975-01-01

    An experimental study was conducted to examine the aeroacoustic mechanism that produces externally blown flap (EBF) scrubbing noise, i.e. a surface-radiated noise which is generally strongest normal to UTW deflected flaps. Scrubbing noise was not radiated from portions of the surface adjacent to strong, locally coherent turbulent eddies. Instead, scrubbing noise seemed to come from weak loading fluctuations that were coherent along the scrubbed span. These loading fluctuations probably were induced by the convected large-scale vortex structure of the attached exhaust jet. Deflecting a UTW flap would reduce the distance between the vortex trajectory and the flap surface, increasing the resulting dipole noise and rotating its directivity. In contrast, deflecting a USB flap would increase this distance, so that observable scrubbing noise would be radiated only from the undeflected forward portion of the wing.

  2. Scrubbing of iodine from gas streams with mercuric nitrate-conversion of mercuric iodate product to barium iodate for fixation in concrete

    SciTech Connect

    Rogers, G.C.; Moore, J.G.; Morgan, M.T.

    1980-06-01

    A bench-scale model of a mercuric nitrate scrubber for removal of iodine from off-gas streams was constructed and operated in conjunction with a mercuric iodate-to-barium iodate conversion system to determine the feasibility of total recycle of all processing solutions. The two main aspects of the system examined were (1) the extent of contamination of the barium iodate product, and (2) the effect of cross-contamination of various process solutions on the efficiency of the process. The experimental evidence obtained indicates that, with appropriate control, all solutions can be recycled without significant contamination of the product that would be harmful to the host concrete or to the environment. Mercury contamination was found to be less than or equal to 0.5 wt % of the barium iodate product. The most significant effect on system efficiency was determined to be barium hydroxide contamination of the sodium hydroxide solution used to convert mercuric iodate to sodium iodate. A mole ratio of barium hydroxide to sodium hydroxide of about 1:225 caused a decrease in conversion efficiency of about 45%.

  3. Capture and release of acid-gasses with acid-gas binding organic compounds

    DOEpatents

    Heldebrant, David J; Yonker, Clement R; Koech, Phillip K

    2015-03-17

    A system and method for acid-gas capture wherein organic acid-gas capture materials form hetero-atom analogs of alkyl-carbonate when contacted with an acid gas. These organic-acid gas capture materials include combinations of a weak acid and a base, or zwitterionic liquids. This invention allows for reversible acid-gas binding to these organic binding materials thus allowing for the capture and release of one or more acid gases. These acid-gas binding organic compounds can be regenerated to release the captured acid gasses and enable these organic acid-gas binding materials to be reused. This enables transport of the liquid capture compounds and the release of the acid gases from the organic liquid with significant energy savings compared to current aqueous systems.

  4. Using Willie's Acid-Base Box for Blood Gas Analysis

    ERIC Educational Resources Information Center

    Dietz, John R.

    2011-01-01

    In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

  5. Cryogenic fractionator gas as stripping gas of fines slurry in a coking and gasification process

    DOEpatents

    DeGeorge, Charles W.

    1981-01-01

    In an integrated coking and gasification process wherein a stream of fluidized solids is passed from a fluidized bed coking zone to a second fluidized bed and wherein entrained solid fines are recovered by a scrubbing process and wherein the resulting solids-liquid slurry is stripped with a stripping gas to remove acidic gases, at least a portion of the stripping gas comprises a gas comprising hydrogen, nitrogen and methane separated from the coker products.

  6. Treatment of odorous sulphur compounds by chemical scrubbing with hydrogen peroxide--stabilisation of the scrubbing solution.

    PubMed

    Charron, Isabelle; Couvert, Annabelle; Laplanche, Alain; Renner, Christophe; Patria, Lucie; Requieme, Benoît

    2006-12-15

    To slow down the hydrogen peroxide decomposition in basic aqueous conditions, the addition of stabilizers and co-stabilizers in the scrubbing solution was investigated. Results found with sodium silicate (Na2SiO3) were quite promising but several problems still remained. Based on these observations, this study focused on the research of a better stabilizer. Several ways were investigated: the use of silicate solutions employed in pulp industries, the addition of co-stabilizers to sodium silicate, or the use of an another stabilizer (the poly-alpha-hydroxyacrylic acid). Experiments revealed that the poly-alpha-hydroxyacrylic acid is the best stabilizing compound.

  7. Hollow fiber gas-liquid membrane contactors for acid gas capture: a review.

    PubMed

    Mansourizadeh, A; Ismail, A F

    2009-11-15

    Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas-liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas-liquid membrane contactors for acid gas removal were also briefly discussed.

  8. Ecological considerations in scrub typhus*

    PubMed Central

    Traub, Robert; Wisseman, Charles L.

    1968-01-01

    Certain features, characteristic of outbreaks of scrub typhus, can be explained by the behaviour of the chigger vectors which are remarkably hardy and can survive weeks of freezing or immersion in water. The established vectors are all species of the genus Leptotrombidium (Leptotrombidium), i.e., L. (L.) akamushi (Brumpt, 1910), L. (L.) deliense (Walch, 1922), L. (L.) pallidum (Nagayo et al., 1919), and L. (L.) scutellare (Nagayo et al., 1921). These chiggers (i.e. larval mites) infest a broad variety of birds and mammals, and tend to be found in clusters on certain specific sites on the host. However, the precise site for any species of mite varies with the host, and it is believed that the grooming habits of the infested animal account for this “site preference”. The degree of infestation cannot validly be ascribed to the size of the host. L. (L.) pavlovskyi (Schluger, 1948), L. (L.) orientale (Schluger, 1948), L. (L.) arenicola Traub, 1960, and L. (L.) tosa (Sasa & Kowashima, 1951) are regarded as probable vectors. Other species, some belonging to other genera, are under suspicion in this regard. L. (L.) subintermedium (Jameson & Toshioka, 1954) and certain other chiggers were found in “ecological islands” in all montane habitats studied in West Pakistan, despite the intervening high mountains, broad rivers and belts of semi-desert. The infection-rate of Rickettsia tsutsugamushi in vector species in nature is believed to be low, and chiggers may be serving as reservoirs of infection and not just as vectors. PMID:5303405

  9. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    PubMed Central

    2012-01-01

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

  10. Endemic Scrub Typhus in South America.

    PubMed

    Weitzel, Thomas; Dittrich, Sabine; López, Javier; Phuklia, Weerawat; Martinez-Valdebenito, Constanza; Velásquez, Katia; Blacksell, Stuart D; Paris, Daniel H; Abarca, Katia

    2016-09-01

    Scrub typhus is a life-threatening zoonosis caused by Orientia tsutsugamushi organisms that are transmitted by the larvae of trombiculid mites. Endemic scrub typhus was originally thought to be confined to the so called "tsutsugamushi triangle" within the Asia-Pacific region. In 2006, however, two individual cases were detected in the Middle East and South America, which suggested that the pathogen was present farther afield. Here, we report three autochthonous cases of scrub typhus caused by O. tsutsugamushi acquired on Chiloé Island in southern Chile, which suggests the existence of an endemic focus in South America. (Funded by the Chilean Comisión Nacional de Investigación Científica y Tecnológica and the Wellcome Trust.).

  11. Endemic Scrub Typhus in South America.

    PubMed

    Weitzel, Thomas; Dittrich, Sabine; López, Javier; Phuklia, Weerawat; Martinez-Valdebenito, Constanza; Velásquez, Katia; Blacksell, Stuart D; Paris, Daniel H; Abarca, Katia

    2016-09-01

    Scrub typhus is a life-threatening zoonosis caused by Orientia tsutsugamushi organisms that are transmitted by the larvae of trombiculid mites. Endemic scrub typhus was originally thought to be confined to the so called "tsutsugamushi triangle" within the Asia-Pacific region. In 2006, however, two individual cases were detected in the Middle East and South America, which suggested that the pathogen was present farther afield. Here, we report three autochthonous cases of scrub typhus caused by O. tsutsugamushi acquired on Chiloé Island in southern Chile, which suggests the existence of an endemic focus in South America. (Funded by the Chilean Comisión Nacional de Investigación Científica y Tecnológica and the Wellcome Trust.). PMID:27602667

  12. BEAM SCRUBBING FOR RHIC POLARIZED PROTON RUN.

    SciTech Connect

    ZHANG,S.Y.FISCHER,W.HUANG,H.ROSER,T.

    2004-07-05

    One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. A beam scrubbing study shows that with a reasonable period of time of running high intensity 112-bunch proton beam, the pressure rise can be reduced, allowing higher beam intensity.

  13. Acute Pancreatitis Due to Scrub Typhus

    PubMed Central

    Ahmed, Atif Shaikh Iqbal; Kundavaram, Abhilash Paul Prabhakar; Sathyendra, Sowmya; Abraham, Ooriapadickal C

    2014-01-01

    Scrub typhus is endemic in large parts of India and can cause multi-organ failure and death. Acute pancreatitis as a complication is very rare and is potentially fatal. This case series describes seven adult patients who presented with an acute febrile illness and were diagnosed to have scrub typhus with acute pancreatitis. The mean age of the seven patients with acute pancreatitis was 49.4 years, and mean duration of fever prior to presentation was 7.7 days. All seven patients had abdominal pain, and three had a pathognomonic eschar. The mean serum lipase level was 1,509 U/L (normal value: <190 U/L) and the mean serum amylase level was 434 U/L (normal value: <200 U/L). Six patients had evidence of multi-organ dysfunction. Hematological and respiratory system dysfunction was seen in five patients, hepatic and renal dysfunction in four, and central nervous system dysfunction in three patients. Three patients who had ≥4 organs involved, died (mortality rate: 42.8%). Our case series shows that pancreatitis in scrub typhus is an extremely rare complication and when present, is associated with increased mortality (42.8%). Physicians may be familiar with the various complications of scrub typhus but less so with acute pancreatitis and hence may be underdiagnosed. PMID:24741229

  14. FLY ASH RECYCLE IN DRY SCRUBBING

    EPA Science Inventory

    The paper describes the effects of fly ash recycle in dry scrubbing. (Previous workers have shown that the recycle of product solids improves the utilization of slaked lime--Ca(OH)2--for sulfur dioxide (SO2) removal by spray dryers with bag filters.) In laboratory-scale experimen...

  15. The Surgical Scrub. Learning Activity Package.

    ERIC Educational Resources Information Center

    Runge, Lillian

    This learning activity package on the surgical scrub is one of a series of 12 titles developed for use in health occupations education programs. Materials in the package include objectives, a list of materials needed, a list of definitions, information sheets, reviews (self evaluations) of portions of the content, and answers to reviews. These…

  16. STATUS OF SO2 SCRUBBING TECHNOLOGIES

    EPA Science Inventory

    The paper presents the extent of current sulfur dioxide (SO2) scrubber applications on electricity generating units in the U.S. and abroad. The technical performance of recent SO2 scrubber installations is discussed. Recently reported technical innovations to SO2 scrubbing tech...

  17. [Surveillance of scrub typhus in Taiwan].

    PubMed

    Chen, H L; Chen, H Y; Horng, C B

    1993-11-01

    Although scrub typhus, a rickettsial exanthematous febrile disease, has designated as a reportable communicable disease in Taiwan since 1955, only Pescadores island, Hualien and Taitung counties had more reported and confirmed cases. Suspected dengue fever and scrub typhus serum specimens sent from the Bureau of Health and health stations to this institute from January 1991 to December 1992 were tested for antibody to scrub typhus by indirect fluorescent antibody technique (IFA). The results showed that: 1) there were serologically positive cases in many counties except Hsinchu and Iilan, 2) the disease occurred mostly from July to October, 3) more males than females were infected and their age ranged from 21 to 60 years old with a peak of the twenties and 4) higher incidence rate in children under five years old was observed in Pescadores and Orchid islands. The above data call the attention of people and physicians to be aware of the fact that there were probable scrub typhus cases in every county in Taiwan.

  18. Low temperature dry scrubbing reaction kinetics and mechanisms, Volume 1

    SciTech Connect

    Prudich, M.E.; Sampson, K.J.; Reddy, S.N.; Maldei, M.; Ben-Said, L. )

    1992-10-01

    Dry scrubbing that takes place after the air preheater (<350[degree]F) is the mode of operation that is of primary interest to this research project. At the relatively low temperatures that occur in this region of operation the rate of the gas-solid reaction that drives SO[sub 2] capture in the convective (800 to 1200[degree]F) and the combustion (1600 to 2400[degree]F) zones is too slow to be significant. The presence of significant amounts of either liquid-phase or vapor-phase water is required in order to mediate SO[sub 2] capture and to produce reasonable capture rates. A mathematical process model describing the cross-flow, moving-bed Limestone Emission Control (LEC) process has been formulated. This process model incorporates the resistance-in-series SO[sub 2] capture kinetic model described in the Project Year [number sign]1 final report. The kinetic model formulated during Project Year [number sign]1 pointed to limestone solubility and rate of solubilization as being key factors in determining the rate of SO[sub 2] capture in wetted limestone (LEC) scrubbing systems. In Project Year [number sign]2, limestone solubilities and rates of solubilization are being determined for a suite of Ohio limestones.

  19. Removal of nitric oxide from exhaust gas with cyanuric acid--

    SciTech Connect

    Siebers, D.L. . Combustion Research Faclity); Caton, J.A. . Dept. of Mechanical Engineering)

    1990-01-01

    Addition of gaseous isocyanic acid (HNCO) to the exhaust of combustion systems or chemical process is proposed as a method for reducing nitric oxide (NO) emissions. The HNCO selectively reduces NO in the exhaust through a multistep chemical reaction mechanism. This article presents an experimental investigation of the proposed NO reduction process using cyanuric acid as the source of HNCO. At elevated temperature cyanuric acid decomposes and forms HNCO. The effects of temperature, exhaust gas composition, cyanuric acid concentration (i.e., HNCO concentration), and surfaces were examined. The experiments were conducted in an electrically heated quartz flow reactor using either exhaust from a diesel engine or simulated exhaust gas. The results demonstrate that gas phase NO reduction approaching 100% can be obtained.

  20. Acute respiratory failure in scrub typhus patients

    PubMed Central

    Sahoo, Jyoti Narayan; Gurjar, Mohan; Harde, Yogesh

    2016-01-01

    Respiratory failure is a serious complication of scrub typhus. In this prospective study, all patients with a diagnosis of scrub typhus were included from a single center Intensive Care Unit (ICU). Demographic, clinical characteristics, laboratory, and imaging parameters of these patients at the time of ICU admission were compared. Of the 55 scrub typhus patients, 27 (49%) had an acute respiratory failure. Seventeen patients had acute respiratory distress syndrome, and ten had cardiogenic pulmonary edema. Respiratory supported patients were older had significant chronic lungs disease and high severity illness scores (Acute Physiology and Chronic Health Evaluation-II and Sequential Organ Failure Assessment score). At ICU admission, these patients presented with more deranged laboratory markers, including high bilirubin, high creatine kinase, high lactate, metabolic acidosis, low serum albumin, and presence of ascites. The average ICU and hospital stay were 4.27 ± 2.74 and 6.53 ± 3.52 days, respectively, in the respiratory supported group. Three patients died in respiratory failure group, while only one patient died in nonrespiratory failure group.

  1. Acute respiratory failure in scrub typhus patients.

    PubMed

    Sahoo, Jyoti Narayan; Gurjar, Mohan; Harde, Yogesh

    2016-08-01

    Respiratory failure is a serious complication of scrub typhus. In this prospective study, all patients with a diagnosis of scrub typhus were included from a single center Intensive Care Unit (ICU). Demographic, clinical characteristics, laboratory, and imaging parameters of these patients at the time of ICU admission were compared. Of the 55 scrub typhus patients, 27 (49%) had an acute respiratory failure. Seventeen patients had acute respiratory distress syndrome, and ten had cardiogenic pulmonary edema. Respiratory supported patients were older had significant chronic lungs disease and high severity illness scores (Acute Physiology and Chronic Health Evaluation-II and Sequential Organ Failure Assessment score). At ICU admission, these patients presented with more deranged laboratory markers, including high bilirubin, high creatine kinase, high lactate, metabolic acidosis, low serum albumin, and presence of ascites. The average ICU and hospital stay were 4.27 ± 2.74 and 6.53 ± 3.52 days, respectively, in the respiratory supported group. Three patients died in respiratory failure group, while only one patient died in nonrespiratory failure group. PMID:27630462

  2. Acute respiratory failure in scrub typhus patients

    PubMed Central

    Sahoo, Jyoti Narayan; Gurjar, Mohan; Harde, Yogesh

    2016-01-01

    Respiratory failure is a serious complication of scrub typhus. In this prospective study, all patients with a diagnosis of scrub typhus were included from a single center Intensive Care Unit (ICU). Demographic, clinical characteristics, laboratory, and imaging parameters of these patients at the time of ICU admission were compared. Of the 55 scrub typhus patients, 27 (49%) had an acute respiratory failure. Seventeen patients had acute respiratory distress syndrome, and ten had cardiogenic pulmonary edema. Respiratory supported patients were older had significant chronic lungs disease and high severity illness scores (Acute Physiology and Chronic Health Evaluation-II and Sequential Organ Failure Assessment score). At ICU admission, these patients presented with more deranged laboratory markers, including high bilirubin, high creatine kinase, high lactate, metabolic acidosis, low serum albumin, and presence of ascites. The average ICU and hospital stay were 4.27 ± 2.74 and 6.53 ± 3.52 days, respectively, in the respiratory supported group. Three patients died in respiratory failure group, while only one patient died in nonrespiratory failure group. PMID:27630462

  3. Surgical hand hygiene: scrub or rub?

    PubMed

    Widmer, A F

    2013-02-01

    Surgical hand hygiene is standard care prior to any surgical procedure. Per-operative glove punctures are observed in almost 30% of all interventions, and a risk factor for postoperative infections. In the past, washing hands with antimicrobial soap and water (surgical scrub) was the norm, mainly with chlorhexidine or iodine. More recently, alcohol-based hand rub has been successfully introduced, showing greater effectiveness, less irritation to the hands, and requiring less time than washing hands. All products should have a remnant effect that delays microbial growth under the gloved hand. Some of the alcohol-based compounds are effective (as determined by the European Norm EN 12791) within 90 s whereas others require 3-5 min, similar to the scrub. The short procedure relies heavily on proper technique and timing, since lowering the exposure time to <90 s leads to significantly lower effectiveness of bacterial killing. Today, surgical hand hygiene should meet EN 12791 in Europe, or other standards, such as the US Food and Drug Administration tentative final monograph norm in the USA. It is best performed by using an alcohol-based hand rub, but a scrub with chlorhexidine-containing soap also meets these standards.

  4. Acute respiratory failure in scrub typhus patients.

    PubMed

    Sahoo, Jyoti Narayan; Gurjar, Mohan; Harde, Yogesh

    2016-08-01

    Respiratory failure is a serious complication of scrub typhus. In this prospective study, all patients with a diagnosis of scrub typhus were included from a single center Intensive Care Unit (ICU). Demographic, clinical characteristics, laboratory, and imaging parameters of these patients at the time of ICU admission were compared. Of the 55 scrub typhus patients, 27 (49%) had an acute respiratory failure. Seventeen patients had acute respiratory distress syndrome, and ten had cardiogenic pulmonary edema. Respiratory supported patients were older had significant chronic lungs disease and high severity illness scores (Acute Physiology and Chronic Health Evaluation-II and Sequential Organ Failure Assessment score). At ICU admission, these patients presented with more deranged laboratory markers, including high bilirubin, high creatine kinase, high lactate, metabolic acidosis, low serum albumin, and presence of ascites. The average ICU and hospital stay were 4.27 ± 2.74 and 6.53 ± 3.52 days, respectively, in the respiratory supported group. Three patients died in respiratory failure group, while only one patient died in nonrespiratory failure group.

  5. Surgical hand hygiene: scrub or rub?

    PubMed

    Widmer, A F

    2013-02-01

    Surgical hand hygiene is standard care prior to any surgical procedure. Per-operative glove punctures are observed in almost 30% of all interventions, and a risk factor for postoperative infections. In the past, washing hands with antimicrobial soap and water (surgical scrub) was the norm, mainly with chlorhexidine or iodine. More recently, alcohol-based hand rub has been successfully introduced, showing greater effectiveness, less irritation to the hands, and requiring less time than washing hands. All products should have a remnant effect that delays microbial growth under the gloved hand. Some of the alcohol-based compounds are effective (as determined by the European Norm EN 12791) within 90 s whereas others require 3-5 min, similar to the scrub. The short procedure relies heavily on proper technique and timing, since lowering the exposure time to <90 s leads to significantly lower effectiveness of bacterial killing. Today, surgical hand hygiene should meet EN 12791 in Europe, or other standards, such as the US Food and Drug Administration tentative final monograph norm in the USA. It is best performed by using an alcohol-based hand rub, but a scrub with chlorhexidine-containing soap also meets these standards. PMID:23453175

  6. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  7. An investigation on NO removal by wet scrubbing using NaClO2 seawater solution.

    PubMed

    Han, Zhitao; Yang, Shaolong; Zheng, Dekang; Pan, Xinxiang; Yan, Zhijun

    2016-01-01

    The experiments were conducted to investigate the NO removal by wet scrubbing using NaClO2 seawater solution in a cyclic scrubbing mode. Results show that, when the concentration of NaClO2 in scrubbing solution is higher than 10 mM, a complete removal of NO can be achieved during the cyclic scrubbing process. The breakthrough time for seawater with 15 mM NaClO2 is enhanced by 34.3 % compared with that for NaClO2 freshwater. The extension of the breakthrough time for NaClO2 seawater is mainly ascribed to the improved utilization of NaClO2 in the solution. The good buffering ability of seawater could suppress the acidic decomposition of NaClO2 into ClO2 effectively. The analysis of reaction products indicates that the main anions in the spent liquor are chloride ions and nitrate ions. The calculation of NaClO2 utilization according to the ion chromatography also agrees well with the experimental results of breakthrough times. PMID:27386234

  8. Acid gas extraction of pyridine from water

    SciTech Connect

    Laitinen, A.; Kaunisto, J.

    2000-01-01

    Pyridine was extracted from aqueous solutions initially containing 5 or 15 wt % pyridine by using liquid or supercritical carbon dioxide at 10 MPa as a solvent in a mechanically agitated countercurrent extraction column. The lowest pyridine concentration in the raffinate was 0.06 wt %, whereas the pyridine concentration in the extract was 86--94 wt %. From the initial amount of pyridine, 96--99% was transferred from the feed stream to the extract by using relatively small solvent-to-feed ratios of 2.8--4.6 (kg of solvent/kg of feed). The measured distribution coefficients for the water/pyridine/carbon dioxide system ranged from 0.3 to 1 (weight units), depending on the initial pyridine concentration in water. Carbon dioxide is a particularly suitable solvent for the extraction of pyridine from concentrated aqueous solutions. The efficiency may be the result of an acid-base interaction between weakly basic pyridine solute and weakly acidic carbon dioxide solvent in an aqueous environment.

  9. Gas dilution system results and application to acid rain utilities

    SciTech Connect

    Jolley-Souders, K.; Geib, R.; Dunn, C.

    1997-12-31

    In 1997, the United States EPA will remove restrictions preventing acid rain utilities from using gas dilution systems for calibration or linearity studies for continuous emissions monitoring, Test Method 205 in 40CFR51 requires that a gas dilution system must produce calibration gases whose measured values are within {+-}2% of predicted values. This paper presents the evaluation of the Environics/CalMat 2020 Dilution System for use in calibration studies. Internal studies show that concentrations generated by this unit are within {+-}0.5% of predicted values. Studies are being conducted by several acid rain utilities to evaluate the Environics/CalMat system using single minor component calibration standards. In addition, an internally generated study is being performed to demonstrate the system`s accuracy using a multi-component gas mixture. Data from these tests will be presented in the final version of the paper.

  10. Direct molecular hydrogen sulphide scrubbing with hollowfibre membranes.

    PubMed

    Boucif, N; Jefferson, B; Parsons-, S A; Judd, S J; Stuetz, R M

    2001-01-01

    The emission of hydrogen sulphide is a major problem associated with anaerobic treatment of sulphate and sulphite containing wastewaters. Conventional absorbing processes, such as packed towers, spray towers or bubble columns, are all constrained by factors such as flooding and foaming. Membrane systems, on the other hand, enable independent control of the liquid and gas flow rate and a step change order of magnitude increase in the specific surface area of the contact process. The membrane acts as a gas absorber with a design similar to a shell and tube heat exchanger. On the other hand, they are limited by facets of the membrane such as its resistance to mass transfer and permselectivity, as well as its cost. The work presented in this paper refers to an absorption process based on a non-wetted hollow fibre membrane for the scrubbing of hydrogen sulphide from air, with water as the contact solvent. Results presented describe the performance of the unit in terms of overall transfer and outlet liquid concentration as a function of circulation regime, gas flow rate, liquid flow rate and specific surface area. In particular, results are presented using traditional plots of Sherwood number (Sh) against Graetz (Gr) number for the liquid flowing in the lumens, such that experimental and available empirical descriptions of the process performance are directly compared. Results suggest that, as expected, very efficient mass transfer is obtained. However, the mass transfer was found to reach a maximum value against Gr, contrary to available empirical models.

  11. Interactions between greenhouse gas policies and acid rain control strategies

    SciTech Connect

    Klein, D.E.; Kane, R.L.; Mansueti, L.

    1997-12-31

    Conventional wisdom and much of the public policy debate have usually drawn a clean delineation between acid rain issues and global warming concerns. This traditional approach of evaluating one policy at a time is too simplistic to serve as a framework for electric utilities making major capital investment and fuel procurement decisions to comply with various environmental requirements. Potential Climate change regulation can affect acid rain compliance decisions, and acid rain compliance decisions will affect future GHG emissions. This paper explores two categories of linkages between these different environmental issues. First, the assumptions one makes regarding future climate change policies can have a profound impact on the economic attractiveness of various acid rain compliance strategies. Second, decisions regarding acid rain compliance strategy can have greenhouse gas implications that might prove more or less difficult to address in future climate change legislation.

  12. Incinerator system arrangement with dual scrubbing chambers

    SciTech Connect

    Domnitch, I.

    1987-01-13

    An incinerator arrangement is described comprising: an incinerator housing located near the lowest point in a building, the housing containing incinerator elements therein; a chute-flue having a first end in communication with the incinerator housing, a second end at the top of the building for evacuation of combustion gases to the atmosphere therethrough, and at least one intermediately located waste disposal opening through which waste is dropped into the incinerator housing; the incinerator elements including: a main combustion chamber, an opening between the main combustion chamber and the first end of the chute-flue and a flue-damper covering the opening. The flue-damper is biased in a closed position and being operable by the weight of waste to admit the waste into the combustion chamber; a scrubbing chamber located exteriorly along the top of the combustion chamber and having a first opening into the combustion chamber and a second opening into the chute-flue; and water spraying means in the scrubbing chamber for directing a water spray at the combustion gases to wash particulate matter from the gases before the gases enter the chute-flue whereby the water spraying means which are located adjacent the combustion chamber are protected against freezing and the elements.

  13. Scrub Typhus Incidence Modeling with Meteorological Factors in South Korea

    PubMed Central

    Kwak, Jaewon; Kim, Soojun; Kim, Gilho; Singh, Vijay P.; Hong, Seungjin; Kim, Hung Soo

    2015-01-01

    Since its recurrence in 1986, scrub typhus has been occurring annually and it is considered as one of the most prevalent diseases in Korea. Scrub typhus is a 3rd grade nationally notifiable disease that has greatly increased in Korea since 2000. The objective of this study is to construct a disease incidence model for prediction and quantification of the incidences of scrub typhus. Using data from 2001 to 2010, the incidence Artificial Neural Network (ANN) model, which considers the time-lag between scrub typhus and minimum temperature, precipitation and average wind speed based on the Granger causality and spectral analysis, is constructed and tested for 2011 to 2012. Results show reliable simulation of scrub typhus incidences with selected predictors, and indicate that the seasonality in meteorological data should be considered. PMID:26132479

  14. Gas-phase NMR studies of alcohols. Intrinsic acidities

    NASA Astrophysics Data System (ADS)

    Chauvel, J. Paul; True, Nancy S.

    1985-05-01

    Gas-phase (≈100 Torr) 1H NMR spectra of eighteen simple aliphatic and unsaturated alcohols, four fluorinated alcohols, and two thiols were obtained at 148.6°C where hydrogen bonding has little effect on chemical shifts. For the methanol, ethanol, n-propanol, i-propanol, t-butanol, i- butanol, neopentanol, 2,2,2-trifluoroethanol and benzyl alcohol, the observed hydroxylic proton chemical shifts correlate with previously obtained relative gas-phase acidities from thermochemical analysis which employed equilibrium constants of proton transfer reactions measured via mass spectroscopic and ion cyclotron resonance techniques. The correlational dependence is 10.3(0.5) kcal/mol ppm with a correlation coefficient of 0.99. These results demonstrate that the trend of increasing acidity with increasing size of the alkyl substituent is also reflected in the neutral forms of the alcohols, indicating that the polarizability of the ionic forms is not the only determining factor in relative gas-phase acidities of alcohols. Although factors affecting the hydroxylic proton chemical shifts of the larger substituted and unsaturated alcohols are more complex, their observed 1H NMR spectra also reflect this trend. For methanol and ethanol observed gas-phase 1H chemical shifts are also compared with recent theoritical calculations. 3JHH coupling constants across CO bonds are ≈ 5.5 Hz, significantly smaller than typical 3JHH coupling across sp 3 hybrid C C bonds.

  15. A comparison of 5-minute povidone-iodine scrub and 1-minute povidone-iodine scrub followed by alcohol foam.

    PubMed

    Deshmukh, N; Kramer, J W; Kjellberg, S I

    1998-03-01

    The purpose of this study was to determine if a 1-minute scrub with povidone-iodine followed by alcohol foam is as effective as a 5-minute scrub with povidone-iodine in reducing skin bacterial counts. A 1-minute scrub with povidone-iodine followed by alcohol foam and a 5-minute scrub with povidone-iodine was done. In the first study, cultures were obtained after 1 hour, and in the second study, cultures were obtained after 2 hours. Cultures were obtained by imprinting the first, second, and third fingers on nutrient agar plates. Bacterial counts were then obtained at 24 and 48 hours. The study involved two groups of 12 participants and a total of 37 patients over a period of 5 months. The results show that there was no significant difference between the number of colonies cultured for the 1-minute scrub compared with the 5-minute scrub for either the 1-hour or the 2-hour study. In fact, the total number of bacterial colonies was less after the 1-minute scrub with alcohol foam than after the standard 5-minute scrub in both the 1-hour group (10 vs. 18) and the 2-hour group (18 vs. 44).

  16. Modeling acid-gas generation from boiling chloride brines

    PubMed Central

    2009-01-01

    Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation

  17. Modeling acid-gas generation from boiling chloride brines

    SciTech Connect

    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  18. Fatty acids determination in Bronte pistachios by gas chromatographic method.

    PubMed

    Pantano, Licia; Lo Cascio, Giovanni; Alongi, Angelina; Cammilleri, Gaetano; Vella, Antonio; Macaluso, Andrea; Cicero, Nicola; Migliazzo, Aldo; Ferrantelli, Vincenzo

    2016-10-01

    A gas chromatographic with flame ionization detector (GC-MS FID) method for the identification and quantification of fatty acids based on the extraction of lipids and derivatisation of free acids to form methyl esters was developed and validated. The proposed method was evaluated to a number of standard FAs, and Bronte pistachios samples were used for that purpose and to demonstrate the applicability of the proposed method. In this regard, repeatability, mean and standard deviation of the analytical procedure were calculated. The results obtained have demonstrated oleic acid as the main component of Bronte pistachios (72.2%) followed by linoleic acid (13.4%) and showed some differences in composition with respect to Tunisian, Turkish and Iranian pistachios.

  19. Estimation of brassylic acid by gas chromatography-mass spectrometry

    SciTech Connect

    Mohammed J. Nasrullah, Erica N. Pfarr, Pooja Thapliyal, Nicholas S. Dusek, Kristofer L. Schiele, Christy Gallagher-Lein, and James A. Bahr

    2010-10-29

    The main focus of this work is to estimate Brassylic Acid (BA) using gas chromatography-mass spectrometry (GC-MS). BA is a product obtained from the oxidative cleavage of Erucic Acid (EA). BA has various applications for making nylons and high performance polymers. BA is a 13 carbon compound with two carboxylic acid functional groups at the terminal end. BA has a long hydrocarbon chain that makes the molecule less sensitive to some of the characterization techniques. Although BA can be characterized by NMR, both the starting material (EA) and products BA and nonanoic acid (NA) have peaks at similar {delta}, ppm values. Hence it becomes difficult for the quick estimation of BA during its synthesis.

  20. Fatty acids determination in Bronte pistachios by gas chromatographic method.

    PubMed

    Pantano, Licia; Lo Cascio, Giovanni; Alongi, Angelina; Cammilleri, Gaetano; Vella, Antonio; Macaluso, Andrea; Cicero, Nicola; Migliazzo, Aldo; Ferrantelli, Vincenzo

    2016-10-01

    A gas chromatographic with flame ionization detector (GC-MS FID) method for the identification and quantification of fatty acids based on the extraction of lipids and derivatisation of free acids to form methyl esters was developed and validated. The proposed method was evaluated to a number of standard FAs, and Bronte pistachios samples were used for that purpose and to demonstrate the applicability of the proposed method. In this regard, repeatability, mean and standard deviation of the analytical procedure were calculated. The results obtained have demonstrated oleic acid as the main component of Bronte pistachios (72.2%) followed by linoleic acid (13.4%) and showed some differences in composition with respect to Tunisian, Turkish and Iranian pistachios. PMID:27265004

  1. Comparative evaluation of surgical scrub preparations.

    PubMed

    Peterson, A F; Rosenberg, A; Alatary, S D

    1978-01-01

    The efficacy of 0.75 per cent available povidone-iodine scrub solution, 4 per cent chlorhexidine gluconate detergent solution and 3 per cent hexachlorophene emulsion against resident and transient flora of the hand has been compared using two currently accepted study designs. Chlorhexidine gluconate produced the greatest initial reductions against resident flora, followed by povidone-iodine and hexachlorophene, respectively. In subsequent washings, all three treatments further reduced the flora, chlorhexidine giving the greatest reduction on any test day. On gloved hands, there was significant regrowth following the use of povidone-iodine; there was no such significant regrowth on gloved hands which had been washed with chlorhexidine gluconate or hexachlorophene. Against transient flora, chlorhexidine gluconate gave the lowest over-all counts, followed by povidone-iodine and hexachlorophene, respectively. The reductions in bacteria counts increased following the repetitive use of chlorhexidine; no such trend was noted with either povidone-iodine or hexachlorophene.

  2. Fundamental thermochemical properties of amino acids: gas-phase and aqueous acidities and gas-phase heats of formation.

    PubMed

    Stover, Michele L; Jackson, Virgil E; Matus, Myrna H; Adams, Margaret A; Cassady, Carolyn J; Dixon, David A

    2012-03-01

    The gas-phase acidities of the 20 L-amino acids have been predicted at the composite G3(MP2) level. A broad range of structures of the neutral and anion were studied to determine the lowest energy conformer. Excellent agreement is found with the available experimental gas-phase deprotonation enthalpies, and the calculated values are within experimental error. We predict that tyrosine is deprotonated at the CO(2)H site. Cysteine is predicted to be deprotonated at the SH but the proton on the CO(2)H is shared with the S(-) site. Self-consistent reaction field (SCRF) calculations with the COSMO parametrization were used to predict the pK(a)'s of the non-zwitterion form in aqueous solution. The differences in the non-zwitterion pK(a) values were used to estimate the free energy difference between the zwitterion and nonzwitterion forms in solution. The heats of formation of the neutral compounds were calculated from atomization energies and isodesmic reactions to provide the first reliable set of these values in the gas phase. Further calculations were performed on five rare amino acids to predict their heats of formation, acidities, and pK(a) values.

  3. Reclamation of acid, toxic coal spoils using wet flue gas desulfurization by-product, fly ash and sewage sludge. Final report

    SciTech Connect

    Kost, D.A.; Vimmerstedt, J.P.; Stehouwer, R.C.

    1997-03-01

    Establishment of vegetation on acid abandoned minelands requires modification of soil physical and chemical conditions. Covering the acid minesoil with topsoil or borrow soil is a common practice but this method may be restricted by availability of borrow soil and cause damage to the borrow site. An alternative approach is to use waste materials as soil amendments. There is a long history of using sewage sludge and fly ash as amendments for acid minesoils. Flue gas desulfurization (FGD) by-products are newer materials that are also promising amendments. Most flue gas sludges are mixtures of Calcium sulfate (CaSO{sub 4}), calcium sulfite (CaSO{sub 3}), calcium carbonate (CaCO{sub 3}), calcium hydroxide [Ca(OH){sub 2}], and fly ash. Some scrubbing processes produce almost pure gypsum (CaSO{sub 4}2H{sub 2}O). The primary purpose of the project is to evaluate two wet FGD by-products for effects on vegetation establishment and surface and ground water quality on an acid minesoil. One by-product from the Conesville, OH power plant (American Electric Power Service Corporation) contains primarily calcium sulfite and fly ash. The other by-product (Mg-gypsum FGD) from an experimental scrubber at the Zimmer power plant (Cincinnati Gas and Electric Company) is primarily gypsum with 4% magnesium hydroxide. These materials were compared with borrow soil and sewage sludge as minesoil amendments. Combinations of each FGD sludge with sewage sludge were also tested. This report summarizes two years of measurements of chemical composition of runoff water, ground water at two depths in the subsoil, soil chemical properties, elemental composition and yield of herbaceous ground cover, and elemental composition, survival and height of trees planted on plots treated with the various amendments. The borrow soil is the control for comparison with the other treatments.

  4. Gas flushing through hyper-acidic crater lakes: the next steps within a reframed monitoring time window

    NASA Astrophysics Data System (ADS)

    Rouwet, Dmitri

    2016-04-01

    Tracking variations in the chemical composition, water temperature and pH of brines from peak-activity crater lakes is the most obvious way to forecast phreatic activity. Volcano monitoring intrinsically implies a time window of observation that should be synchronised with the kinetics of magmatic processes, such as degassing and magma intrusion. To decipher "how much time ago" a variation in degassing regime actually occurred before eventually being detected in a crater lake is key, and depends on the lake water residence time. The above reasoning assumes that gas is preserved as anions in the lake water (SO4, Cl, F anions), in other words, that scrubbing of acid gases is complete and irreversible. Less is true. Recent work has confirmed, by direct MultiGas measurement from evaporative plumes, that even the strongest acid in liquid medium (i.e. SO2) degasses from hyper-acidic crater lakes. The less strong acid HCl has long been recognised as being more volatile than hydrophyle in extremely acidic solutions (pH near 0), through a long-term steady increase in SO4/Cl ratios in the vigorously evaporating crater lake of Poás volcano. We now know that acidic gases flush through hyper-acidic crater lake brines, but we don't know to which extend (completely or partially?), and with which speed. The chemical composition hence only reflects a transient phase of the gas flushing through the lake. In terms of volcanic surveillance this brings the advantage that the monitoring time window is definitely shorter than defined by the water chemistry, but yet, we do not know how much shorter. Empirical experiments by Capaccioni et al. (in press) have tried to tackle this kinetic problem for HCl degassing from a "lab-lake" on the short-term (2 days). With this state of the art in mind, two new monitoring strategies can be proposed to seek for precursory signals of phreatic eruptions from crater lakes: (1) Tracking variations in gas compositions, fluxes and ratios between species in

  5. Masticophis flagellum selects florida scrub habitat at multiple spatial scales

    USGS Publications Warehouse

    Halstead, B.J.; Mushinsky, H.R.; McCoy, E.D.

    2009-01-01

    The use of space by individual animals strongly influences the spatial extent, abundance, and growth rates of their populations. We analyzed the spatial ecology and habitat selection of Masticophis flagellum (the coachwhip) at three different scales to determine which habitats are most important to this species. Home ranges and mean daily displacements of M. flagellum in Florida were large compared to individuals in other populations of this species. Home ranges contained a greater proportion of Florida scrub habitat than did the study site as a whole, and individuals selected Florida scrub habitat within their home ranges. For both selection of the home range within the study site and selection of habitats within the home range, mesic cutthroat and hydric swamp habitats were avoided. Standardized selection ratios of Florida scrub patches were positively correlated with lizard abundance. Several non-mutually exclusive mechanisms, including foraging success (prey abundance, prey vulnerability, and foraging efficiency), abundance of refugia, and thermoregulatory opportunity may underlie the selection of Florida scrub by M. flagellum. Historic rarity and anthropogenic loss and fragmentation of Florida scrub habitat, coupled with the long-distance movements, large home ranges, and selection of Florida scrub by M. flagellum, indicate that large contiguous tracts of land containing Florida scrub will be essential for the persistence of M. flagellum in central Florida. ?? 2009 by The Herpetologists' League, Inc.

  6. Spatial Distribution Analysis of Scrub Typhus in Korea

    PubMed Central

    Jin, Hong Sung; Chu, Chaeshin; Han, Dong Yeob

    2013-01-01

    Objective: This study analyzes the spatial distribution of scrub typhus in Korea. Methods: A spatial distribution of Orientia tsutsugamushi occurrence using a geographic information system (GIS) is presented, and analyzed by means of spatial clustering and correlations. Results: The provinces of Gangwon-do and Gyeongsangbuk-do show a low incidence throughout the year. Some districts have almost identical environmental conditions of scrub typhus incidence. The land use change of districts does not directly affect the incidence rate. Conclusion: GIS analysis shows the spatial characteristics of scrub typhus. This research can be used to construct a spatial-temporal model to understand the epidemic tsutsugamushi. PMID:24159523

  7. Assessing scrub practitioner non-technical skills: a literature review.

    PubMed

    McClelland, Guy

    2015-01-01

    A review by Catchpole et al (2009) into the causes and types of harm experienced by the surgical patient emphasised the high risk nature of the perioperative period. Investigations into recent failures at NHS organisations have emphasised the relevance of non-technical skills education in improving clinical performance and patient outcomes. However, scrub practitioner non-technical skills are often developed on a tacit basis, making assessment of performance difficult. This literature review identifies strategies that facilitate assessment of non-technical skills during surgery. Recommendations are made that will assist scrub practitioners in using a validated scrub practitioner non-technical skills assessment framework reliably. PMID:26016259

  8. Process for producing and recovering elemental sulfur from acid gas

    SciTech Connect

    Reed, R. L.

    1985-03-26

    A system and process produce high actual levels of sulfur recovery from acid gas. The system includes two conventional Claus reactors and two cold bed adsorption (CBA) reactors. Four condensers are provided, one disposed before each of the catalytic reactors, and one disposed after the CBA reactor. The system includes a gas clean-up treatment zone for hydrogenation, drying and oxidation of gas to provide stoichiometric ratio of H/sub 2/S and SO/sub 2/. The gas is passed through the clean-up treatment zone prior to being fed to the first of the CBA reactors. The system is designed to operate either in a recovery mode or in a regeneration mode. In the recovery mode, the reactors are in series and the CBA reactors are operated below dew point of sulfur. In regeneration mode, effluent from the clean-up treatment zone is heated in a heat exchanger using effluent from the first catalytic reactor as the heat source. The resulting regeneration gas is fed to one of the two CBA reactors to vaporize sulfur and regenerate the catalyst. The vaporized sulfur is recovered in the condenser. The effluent from the condenser is passed to the other CBA reactor which is operated in the recovery mode during regeneration.

  9. Nitrification processes in scrubbing liquid of an exhaust air treatment system of a large-scale pig housing facility.

    PubMed

    Haneke, J; Siemers, V; Van den Weghe, H F A

    2011-01-01

    The use of multi-staged exhaust air treatment systems is an effective method of substantially reducing the emission of ammonia, dust particles and odorous substances. Wet filter walls are able to absorb large amounts of ammonia when scrubbing fluid containing sulphuric acid is used. In addition, due to their large surface areas and the permanent supply of oxygen and nutrients, wet filter walls provide a basis for the development of biofilms containing nitrogen-converting bacteria. Cyclic nitrification processes could be observed in a two-stage exhaust air treatment system, which had been converted to function as a regulated process control system (elutriation at κ = 20 mS cm(-1); pH 6.5-6.8). With this system, the sulphuric acid requirement was periodically reduced every 6-8 weeks to less than 1 kg H(2)SO(4) per fattening place and year. There was an increased formation of nitrous oxide gas during nitrification after the wet filter stage. Electron-microscopic images of the biofilm growing on the wet filter wall showed aggregates of possible ammonium-oxidising and nitrite-oxidising bacteria.

  10. Season-dependent and independent responses of Mediterranean scrub to light conditions.

    PubMed

    Zunzunegui, María; Díaz-Barradas, Mari Cruz; Jáuregui, Juan; Rodríguez, Herminia; Álvarez-Cansino, Leonor

    2016-05-01

    Semi-arid plant species cope with excess of solar radiation with morphological and physiological adaptations that assure their survival when other abiotic stressors interact. At the leaf level, sun and shade plants may differ in the set of traits that regulate environmental stressors. Here, we evaluated if leaf-level physiological seasonal response of Mediterranean scrub species (Myrtus communis, Halimium halimifolium, Rosmarinus officinalis, and Cistus salvifolius) depended on light availability conditions. We aimed to determine which of these responses prevailed independently of the marked seasonality of Mediterranean climate, to define a leaf-level strategy in the scrub community. Thirty six leaf response variables - involving gas exchange, water status, photosystem II photochemical efficiency, photosynthetic pigments and leaf structure - were seasonally measured in sun exposed and shaded plants under field conditions. Physiological responses showed a common pattern throughout the year, in spite of the marked seasonality of the Mediterranean climate and of species-specific differences in the response to light intensity. Variables related to light use, CO2 assimilation, leaf pigment content, and LMA (leaf mass area) presented differences that were consistent throughout the year, although autumn was the season with greater contrast between sun and shade plants. Our data suggest that in Mediterranean scrub shade plants the lutein pool could have an important role in the photoprotection of the photosynthetic tissues. There was a negative linear correlation between the ratio lutein/total chlorophylls and the majority of leaf level variables. The combined effect of abiotic stress factors (light and drought or light and cold) was variable-specific, in some cases enhancing differences between sun and shade plants, while in others leading to unified strategies in all scrub species.

  11. Season-dependent and independent responses of Mediterranean scrub to light conditions.

    PubMed

    Zunzunegui, María; Díaz-Barradas, Mari Cruz; Jáuregui, Juan; Rodríguez, Herminia; Álvarez-Cansino, Leonor

    2016-05-01

    Semi-arid plant species cope with excess of solar radiation with morphological and physiological adaptations that assure their survival when other abiotic stressors interact. At the leaf level, sun and shade plants may differ in the set of traits that regulate environmental stressors. Here, we evaluated if leaf-level physiological seasonal response of Mediterranean scrub species (Myrtus communis, Halimium halimifolium, Rosmarinus officinalis, and Cistus salvifolius) depended on light availability conditions. We aimed to determine which of these responses prevailed independently of the marked seasonality of Mediterranean climate, to define a leaf-level strategy in the scrub community. Thirty six leaf response variables - involving gas exchange, water status, photosystem II photochemical efficiency, photosynthetic pigments and leaf structure - were seasonally measured in sun exposed and shaded plants under field conditions. Physiological responses showed a common pattern throughout the year, in spite of the marked seasonality of the Mediterranean climate and of species-specific differences in the response to light intensity. Variables related to light use, CO2 assimilation, leaf pigment content, and LMA (leaf mass area) presented differences that were consistent throughout the year, although autumn was the season with greater contrast between sun and shade plants. Our data suggest that in Mediterranean scrub shade plants the lutein pool could have an important role in the photoprotection of the photosynthetic tissues. There was a negative linear correlation between the ratio lutein/total chlorophylls and the majority of leaf level variables. The combined effect of abiotic stress factors (light and drought or light and cold) was variable-specific, in some cases enhancing differences between sun and shade plants, while in others leading to unified strategies in all scrub species. PMID:26913795

  12. Activated carbon passes tests for acid-gas cleanup

    SciTech Connect

    Harruff, L.G.; Bushkuhl, S.J.

    1996-06-24

    Use of activated carbon to remove hydrocarbon contaminants from the acid-gas feed to Claus sulfur-recovery units has been successfully pilot tested in Saudi Arabia. Pilot plant results are discussed here along with issues involved in scale-up to commercial size. Heavy hydrocarbons, particularly benzene, toluene, and xylene (BTX) have been linked to coke formation and catalyst deactivation in Claus converters. This deactivation results in reduced sulfur recovery and increased sulfur emissions from these plants. This clean-up process was proven to be capable of removing 95% of the BTX and other C{sub 6}+s from acid gas over a wide range of actual plant conditions. Following the adsorption step, the activated carbon was easily regenerated by use of low-pressure steam. A post-regeneration drying step using plant fuel gas also proved beneficial. The paper discusses feed contaminants, vapor-phase cleanup, testing design, test parameters and results, bed drying after regeneration, regeneration conditions, basic flow, system control, and full-scale installation.

  13. Combined electrostatic precipitator and acidic gas removal system

    SciTech Connect

    Sparks, L.E.; Plaks, N.

    1989-12-05

    This patent describes a method of retrofitting an apparatus for removing acidic gas and particulate matter from air. The device to be retrofit including an electrostatic precipitator, lacking a precharger, positioned within a housing, a flue gas generating means outside the housing, an entry port in the housing and upstream of the electrostatic precipitator; an exit port in the housing and downstream of the electrostatic precipitator; and ductwork, outside the housing, leading from the generating means to the entry port. The retrofitting comprising the steps of: substituting electrostatic filtration units, for dry electrostatic precipitation, each comprising a precharger and a downstream particle collector having wires of from 1/4 to 1/2 inch in diameter for the electrostatic precipitator. The substituted units being designed so as to occupy less space in the housing that the electrostatic filter lacking a precharger, thereby leaving free space within the housing between a one of the prechargers which is first downstream from the entry port and the exit port and inserting an acidic gas removal means, within the housing.

  14. An empirical model for gas phase acidity and basicity estimation.

    PubMed

    You, H; Kim, G E; Na, C H; Lee, S; Lee, C J; Cho, K-H; Akiyama, Y; Ishida, T; No, K T

    2014-01-01

    Gas phase acidity and basicity estimation models have been developed for acidic and basic functional groups of amino acid side-chains and also for a number of small organic molecules. The acidic functional groups include aliphatic and aromatic alcohol, and aliphatic and aromatic carboxylic acid, and the basic functional groups include aliphatic, aromatic and hetero-aromatic amines, and also pyridino-, pyrazolo- and imidazolo-groupings. The models are described in terms of a linear combination of descriptors that highly influence reactivity at the reaction centres of the functional groups. In order to describe the chemical environments of the deprotonating and protonating sites, atomic descriptors such as the effective atomic electronegativity and effective atomic polarizability of the atoms in the reaction field and the electrostatic potentials at the reaction sites have been introduced. The coefficient of determination (r(2)) of each model is above 0.8, apart from the imidazole model. The models are readily applicable, ranging from simple organic molecules to proteins.

  15. Measurement of Gas-phase Acids in Diesel Exhaust

    NASA Astrophysics Data System (ADS)

    Wentzell, J. J.; Liggio, J.; Li, S.; Vlasenko, A. L.; Staebler, R. M.; Brook, J.; Lu, G.; Poitras, M.; Chan, T.

    2012-12-01

    Gas-phase acids were measured using chemical ionization mass spectrometry (CIMS) as part of the Diesel Engine Emission Research Experiment (DEERE). The CIMS technique, utilizing acetate ion (CH3COO-) as a reagent ion, proved to be a rapid (measurements on the order of seconds) and sensitive (several counts/pptv) method of quantifying the acid emissions. Diluted diesel exhaust measurements were made from a Constant Volume Sampling dilution tunnel using a light duty (1.9L turbocharged Volkswagen Jetta TDI) diesel engine equipped with an OEM diesel oxidation catalyst and exhaust gas recirculation, mounted on an engine dynamometer. Acids measured included isocyanic, nitrous, nitric, propionic and sum of lactic and oxalic, as well as other unidentified compounds. Complimentary measurements of CO, CO2, Total Hydrocarbon (THC), and NOx, were also performed. Several engine modes (different engine rpm and torque outputs) at steady state were examined to determine their effect on acid emissions. Emission rates with respect to NOx and fuel based emission factors were determined. Measurements of HONO fuel emission factors agree well with real-world measurements within a traffic tunnel.1 The first estimate of isocyanic acid emission factors from a diesel engine is reported, and suggests that the emission of this highly toxic compound in diesel exhaust should not be ignored. 1. Kurtenbach, R., Becker, K. H., Gomes, J. A. G., Kleffmann, J.,Lorzer, J. C., Spittler, M., Wiesen, P., Ackermann, R., Geyer, A.,and Platt, U.: Investigations of emissions and heterogeneous formation of HONO in a road traffic tunnel, Atmos. Environ., 35, 3385-3394, doi:10.1016/S1352-2310(01)00138-8, 2001.

  16. Influence of attrition scrubbing, ultrasonic treatment, and oxidant additions on uranium removal from contaminated soils

    SciTech Connect

    Timpson, M.E.; Elless, M.P.; Francis, C.W.

    1994-06-01

    As part of the Uranium in Soils Integrated Demonstration Project being conducted by the US Department of Energy, bench-scale investigations of selective leaching of uranium from soils at the Fernald Environmental Management Project site in Ohio were conducted at Oak Ridge National Laboratory. Two soils (storage pad soil and incinerator soil), representing the major contaminant sources at the site, were extracted using carbonate- and citric acid-based lixiviants. Physical and chemical processes were used in combination with the two extractants to increase the rate of uranium release from these soils. Attrition scrubbing and ultrasonic dispersion were the two physical processes utilized. Potassium permanganate was used as an oxidizing agent to transform tetravalent uranium to the hexavalent state. Hexavalent uranium is easily complexed in solution by the carbonate radical. Attrition scrubbing increased the rate of uranium release from both soils when compared with rotary shaking. At equivalent extraction times and solids loadings, however, attrition scrubbing proved effective only on the incinerator soil. Ultrasonic treatments on the incinerator soil removed 71% of the uranium contamination in a single extraction. Multiple extractions of the same sample removed up to 90% of the uranium. Additions of potassium permanganate to the carbonate extractant resulted in significant changes in the extractability of uranium from the incinerator soil but had no effect on the storage pad soil.

  17. Should surgeons scrub with chlorhexidine or iodine prior to surgery?

    PubMed

    Jarral, Omar A; McCormack, David J; Ibrahim, Sammra; Shipolini, Alex R

    2011-06-01

    A best evidence topic was written according to a structured protocol. The question addressed was whether chlorhexidine gluconate is equivalent or superior to the use of povidone-iodine during surgical hand scrub. A total of 593 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. We conclude that whilst both chlorhexidine and povidone-iodine reduce bacterial count after scrubbing, the effect of chlorhexidine is both more profound and longer lasting. The studies found analysed the difference in reduction in colony forming units or bacterial count following surgical scrub in order to conclude that chlorhexidine was superior. Four studies went further to analyse cumulative and residual activity by testing for bacterial reduction after using a scrub solution for a number of days, an area in which chlorhexidine showed consistent advantages over povidone-iodine. These findings are given more credibility by the clinical finding of a recent meta-analysis of over 5000 patients in which chlorhexidine as an antiseptic skin preparation was associated with significantly reduced surgical site infection (SSI) in clean-contaminated surgery. Despite this, there is no evidence suggesting the use of chlorhexidine during hand scrub reduces SSI, which perhaps explains why guidelines from the World Health Organization, the Centers for Disease Control and Prevention and the Association for Perioperative Practice do not recommend one specific antimicrobial over another for hand scrub.

  18. Effectiveness of Septisol Antiseptic Foam as a Surgical Scrub Agent

    PubMed Central

    Dewar, Norman E.; Gravens, Daniel L.

    1973-01-01

    Septisol antiseptic foam (0.23% hexachlorophene in a 46% ethyl alcohol base) is a new surgical scrub agent for both primary and re-entry use that is designed to minimize the harsh effects to the skin of the conventional scrub while retaining effective antibacterial properties. A preliminary surgical scrub study of 1-week duration yielded an immediate reduction in resident flora of 92% from an average single scrub coupled with a residual bacteriostatic effect from repeated use that gave a plateau at 57% of the pretest resident population level. A separate study demonstrated complete elimination of both gram-positive and gram-negative transients from the skin with a single application of the product. In an 8-week surgical scrub study, equal effectiveness was shown between Septisol antiseptic foam and a standard 3% hexachlorophene detergent. However, Septisol antiseptic foam offers considerable advantage in minimizing the harsh effects to the skin of the conventional surgical scrub and results in a substantially lower hemic level of hexachlorophene in the user than that obtained with 3% hexachlorophene detergent. Sampling was conducted by the fingerprint impression plate technique of Gale. PMID:4584593

  19. Jet Surface Interaction-Scrubbing Noise

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas

    2013-01-01

    Generation of sound due to scrubbing of a jet flow past a nearby solid surface is investigated within the framework of the generalized acoustic analogy theory. The analysis applies to the boundary layer noise generated at and near a wall, and excludes the scattered noise component that is produced at the leading or the trailing edge. While compressibility effects are relatively unimportant at very low Mach numbers, frictional heat generation and thermal gradient normal to the surface could play important roles in generation and propagation of sound in high speed jets of practical interest. A general expression is given for the spectral density of the far-field sound as governed by the variable density Pridmore- Brown equation. The propagation Green's function should be solved numerically starting with the boundary conditions on the surface and subject to specified mean velocity and temperature profiles between the surface and the observer. The equivalent sources of aerodynamic sound are associated with non-linear momentum flux and enthalpy flux terms that appear in the linearized Navier-Stokes equations. These multi-pole sources should be modeled and evaluated with input from a Reynolds-Averaged Navier-Stokes (RANS) solver with an appropriate turbulence model.

  20. [Enantioseparation of 2-phenylcarboxylic acid esters by capillary gas chromatography].

    PubMed

    Shi, Xueyan; Liu, Feipeng; Bian, Qinghua

    2016-01-01

    Chiral 2-arylcarboxylic acid derivatives are important intermediates for preparing 2-arylcarboxylic acids, which are non-steroidal anti-inflammatory drugs (NSAIDs). In order to separate 2-phenylcarboxylic acid ester enantiomers by capillary gas chromatography (CGC), 2, 6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin were used as CGC chiral stationary phases, separately, and their enantioseparation abilities to enantiomers of methyl 2-phenylbutanoate, ethyl 2-phenylbutanoate, isopropyl 2-phenylbutanoate, methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were examined. It was found that methyl 2-phenylbutanoate, methyl 2-phenylpropionate and cyclopentyl 2-phenylpropionate were successfully separated by using 2,6-di-O-pentyl-3-O-butyryl-β-cyclodextrin and 2,6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin as CGC chiral stationary phases, respectively. The enantiomer separation abilities of 2, 6-di-O-pentyl-3-O-butyryl-β-cyclodextrin to the three pairs of 2-phenylcarboxylic acid esters tested are superior to those of 2, 6-di-O-benzyl-3-O-heptanoyl-β-cyclodextrin. PMID:27319170

  1. Fluoroalkyl chloroformates in treating amino acids for gas chromatographic analysis.

    PubMed

    Husek, Petr; Simek, Petr; Hartvich, Petr; Zahradnícková, Helena

    2008-04-01

    Novel fluoroalkyl chloroformates with three and four carbon atoms were investigated for the immediate conversion of amino acids into hydrophobic derivatives in water-containing media. Derivatization conditions were extensively studied and optimized sample preparation protocols elaborated. More than 30 amino acids were treated with the particular reagent in isooctane by simply vortexing the reactive organic phase with a slightly basified aqueous medium containing pyridine or 3-picoline as a catalyst. Outstanding separation of nearly all components on 5% phenylmethylsilicone phase in gas chromatographic (GC) analysis with mass spectrometric (MS) or flame ionization detection (FID) required <10 min. Quantitation characteristics involving linearity in the range of 0.1-100 nmol, regression coefficients of 0.999-0.953 (histidine), MS limit of detection (LOD) reaching 0.03 pmol at proline to nearly 20 pmol at glutamic acid, plus electron impact (EI) spectra and diagnostic SIM fragment ions of the derivatives are reported. The novel method is simple, robust and rapid, enabling to treat amino acids in aqueous environment and to analyze them in <15 min. PMID:18242622

  2. GAS-GRAIN MODELING OF ISOCYANIC ACID (HNCO), CYANIC ACID (HOCN), FULMINIC ACID (HCNO), AND ISOFULMINIC ACID (HONC) IN ASSORTED INTERSTELLAR ENVIRONMENTS

    SciTech Connect

    Quan Donghui; Herbst, Eric; Osamura, Yoshihiro; Roueff, Evelyne

    2010-12-20

    Isocyanic acid (HNCO) is a well-known interstellar molecule. Evidence also exists for the presence of two of its metastable isomers in the interstellar medium: HCNO (fulminic acid) and HOCN (cyanic acid). Fulminic acid has been detected toward cold and lukewarm sources, while cyanic acid has been detected both in these sources and in warm sources in the Galactic Center. Gas-phase models can reproduce the abundances of the isomers in cold sources, but overproduce HCNO in the Galactic Center. Here we present a detailed study of a gas-grain model that contains these three isomers, plus a fourth isomer, isofulminic acid (HONC), for four types of sources: hot cores, the warm envelopes of hot cores, lukewarm corinos, and cold cores. The current model is partially able to rationalize the abundances of HNCO, HOCN, and HCNO in cold and warm sources. Predictions for HONC in all environments are also made.

  3. A comparison of wet and dry scrubbing systems for control of metals and dioxin/furan emissions from incinerators

    SciTech Connect

    Farber, P.S.; Huang, H.S.

    1993-07-01

    In Europe and the United States, both wet and dry (including semidry) scrubbing systems are being used for control of emissions from all types of waste incinerators. In terms of the effectiveness of controlling particulates and acid gases, both types of scrubbing systems are capable of meeting US Environmental Protection Agency and European Community limits. Two of the more difficult emissions requirements for an incinerator air-pollution-control system to meet are the metals and the dioxin/furan limits. The dioxin/furan emissions requirement is especially stringent, calling for levels below 1 ng (10{sup {minus}9}) per cubic meter toxic equivalency. The differences between wet and dry scrubbing systems are discussed in this paper, as well as the advantages and disadvantages of each in its application to the control of emissions from incinerators. Particular attention will be paid to control of metals and dioxin/furan emissions and to the sampling and analysis techniques used to measure these emissions. Toxic equivalency factors will be explained, and in particular, the international toxic equivalency factor proposed as the US and European standard will be discussed. This paper will also address some of the techniques being employed to minimize the emissions of toxic compounds and discuss the use of combined wet and dry scrubbing systems for increased assurance of compliance.

  4. [Determination of dimethylbenzoic acid isomers in urine by gas chromatography].

    PubMed

    Kostrzewski, P; Wiaderna-Brycht, A; Czerski, B

    1994-01-01

    Trimethylobenzene (TMB) is a main ingredient of many organic solvents used in industry. In Farbasol (Polish trade name of the solvent) TMB occurs as a mixture of three isomers: pseudocumene (1, 2, 4-TMB) 30%; mesitylene (1, 3, 5-TMB) 15%; hemimellitene (1,2,3-TMB) 5%. As it is known in human organism, TMB is metabolized mainly to dimethylbenzoic (DMBA) and dimethylhippuric (DMHA) acids, and some authors suggest, that the acids excreted in urine can be biological indicators of exposure to TMB. This study was aimed at developing the method of determination of DMBA isomers in urine. Biological material was hydrolyzed with sodium hydroxide and next extracted with diethyl ether. DMBA concentration in urine was determined by gas chromatography using a variant of quantitative analysis with internal standard (5-methyl-2-isopropylphenol, thymol). Analytical parameters of the developed method of determination of DMBA isomers in urine such as linearity, precision, reproducibility, stability (192 days, when urine samples stored at-18 degrees C), detectability limit (400 micrograms/dm3) have been fully compatible with the requirements of biological monitoring. In order to confirm the presence of DMBA isomers in urine, four volunteers were exposed (8 hours) to Farbasol in toxicological chamber. The TMB concentration in the air, determined by means of gas chromatograph (HP 5890), amounted to 100 mg/m3 (MAC value in Poland). In urine samples collected 2,3-; 2,4-; 2,5-; 2,6-; 3,4-; 3,5-dimethylbenzoic acids were identified by means of GC/MSD.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8170375

  5. A 12-MW-scale pilot study of in-duct scrubbing (IDS) using a rotary atomizer

    SciTech Connect

    Samuel, E.A.; Murphy, K.R.; Demian, A.

    1989-11-01

    A low-cost, moderate-removal efficiency, flue gas desulfurization (FGD) technology was selected by the US Department of Energy for pilot demonstration in its Acid Rain Precursor Control Technology Initiative. The process, identified as In-Duct Scrubbing (IDS), applies rotary atomizer techniques developed for lime-based spray dryer FGD while utilizing existing flue gas ductwork and particulate collectors. IDS technology is anticipated to result in a dry desulfurization process with a moderate removal efficiency (50% or greater) for high-sulfur coal-fired boilers. The critical elements for successful application are: (1) adequate mixing of sorbent droplets with flue gas for efficient reaction contact, (2) sufficient residence time to produce a non-wetting product, and (3) appropriate ductwork cross-sectional area to prevent deposition of wet reaction products before particle drying is comple. The ductwork in many older plants, previously modified to meet 1970 Clean Air Act requirements for particulate control, usually meet these criteria. A 12 MW-scale IDS pilot plant was constructed at the Muskingum River Plant of the American Electric Power System. The pilot plant, which operates from a slipstrem attached to the air-preheater outlet duct from the Unit 5 boiler at the Muskingum River Plant (which burns about 4% sulfur coal), is equipped with three atomizer stations to test the IDS concept in vertical and horizontal configurations. In addition, the pilot plant is equipped to test the effect of injecting IDS off- product upstream of the atomizer, on SO{sub 2}and NO{sub x} removals.

  6. CO2 study shows effects on scrub oak environment

    NASA Technical Reports Server (NTRS)

    2000-01-01

    CO2 study site manager and plant physiologist Graham Hymus (left) examines scrub oak foliage while project engineer David Johnson (right) looks on. The life sciences study is showing that rising levels of carbon dioxide in our atmosphere, caused by the burning of fossil fuels, could spur plant growth globally. The site of KSC's study is a natural scrub oak area near the Vehicle Assembly Building. Twelve-foot areas of scrub oak have been enclosed in 16 open-top test chambers into which CO2 has been blown. Five scientists from NASA and the Smithsonian Environmental Research Center in Edgewater, Md., work at the site to monitor experiments and keep the site running. Scientists hope to continue the study another five to 10 years. More information on this study can be found in Release No. 57- 00.

  7. [Determination of docosahexaenoic acid in milk powder by gas chromatography using acid hydrolysis].

    PubMed

    Shao, Shiping; Xiang, Dapeng; Li, Shuang; Xi, Xinglin; Chen, Wenrui

    2015-11-01

    A method to determine docosahexenoic acid (DHA) in milk powder by gas chromatography was established. The milk powder samples were hydrolyzed with hydrochloric acid, extracted to get total fatty acids by Soxhlet extractor, then esterified with potassium hydroxide methanol solution to form methyl esters, and treated with sodium hydrogen sulfate. The optimal experiment conditions were obtained from orthogonal experiment L9(3(3)) which performed with three factors and three levels, and it requires the reaction performed with 1 mol/L potassium hydroxide solution at 25 degrees C for 5 min. The derivative treated with sodium hydrogen sulfate was separated on a column of SP-2560 (100 m x 0.25 mm x 0.20 μm), and determined in 55 min by temperature programming-gas chromatography. Good linearity was obtained in the range 5.0-300 mg/L with the correlation coefficient of 0.999 9. The relative standard deviations (RSDs) were 3.4%, 1.2% and 1.1% for the seven repeated experiments of 10, 50 and 100 mg/L of DHA, respectively. The limit of detection was 2 mg/kg, and the recoveries of DHA were in the range of 90.4%-93.5%. The results are satisfactory through the tests of practical samples. PMID:26939370

  8. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    NASA Astrophysics Data System (ADS)

    Zhao, Yun; Fina, Alberto; Venturello, Alberto; Geobaldo, Francesco

    2013-10-01

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  9. Reactive Transport Modeling of Acid Gas Generation and Condensation

    SciTech Connect

    G. Zhahg; N. Spycher; E. Sonnenthal; C. Steefel

    2005-01-25

    Pulvirenti et al. (2004) recently conducted a laboratory evaporation/condensation experiment on a synthetic solution of primarily calcium chloride. This solution represents one potential type of evaporated pore water at Yucca Mountain, Nevada, a site proposed for geologic storage of high-level nuclear waste. These authors reported that boiling this solution to near dryness (a concentration factor >75,000 relative to actual pore waters) leads to the generation of acid condensate (pH 4.5) presumably due to volatilization of HCl (and minor HF and/or HNO{sub 3}). To investigate the various processes taking place, including boiling, gas transport, and condensation, their experiment was simulated by modifying an existing multicomponent and multiphase reactive transport code (TOUGHREACT). This code was extended with a Pitzer ion-interaction model to deal with high ionic strength. The model of the experiment was set-up to capture the observed increase in boiling temperature (143 C at {approx}1 bar) resulting from high concentrations of dissolved salts (up to 8 m CaCl{sub 2}). The computed HCI fugacity ({approx} 10{sup -4} bars) generated by boiling under these conditions is not sufficient to lower the pH of the condensate (cooled to 80 and 25 C) down to observed values unless the H{sub 2}O mass fraction in gas is reduced below {approx}10%. This is because the condensate becomes progressively diluted by H{sub 2}O gas condensation. However, when the system is modeled to remove water vapor, the computed pH of instantaneous condensates decreases to {approx}1.7, consistent with the experiment (Figure 1). The results also show that the HCl fugacity increases, and calcite, gypsum, sylvite, halite, MgCl{sub 2}4H{sub 2}O and CaCl{sub 2} precipitate sequentially with increasing concentration factors.

  10. Urbanization of Scrub Typhus Disease in South Korea

    PubMed Central

    Park, Sang-Won; Ha, Na-Young; Ryu, Boyeong; Bang, Ji Hwan; Song, Hoyeon; Kim, Yuri; Kim, Gwanghun; Oh, Myoung-don; Cho, Nam-Hyuk; Lee, Jong-koo

    2015-01-01

    Background Scrub typhus is an endemic disease in Asia. It has been a rural disease, but indigenous urban cases have been observed in Seoul, South Korea. Urban scrub typhus may have a significant impact because of the large population. Methods Indigenous urban scrub typhus was epidemiologically identified in Seoul, the largest metropolitan city in South Korea, using national notifiable disease data from 2010 to 2013. For detailed analysis of clinical features, patients from one hospital that reported the majority of cases were selected and compared to a historic control group. Chigger mites were prospectively collected in the city using a direct chigger mite-collecting trap, and identified using both phenotypic and 18S rDNA sequencing analyses. Their infection with Orientia tsutsugamushi was confirmed by sequencing the 56-kDa antigen gene. Results Eighty-eight cases of urban scrub typhus were determined in Seoul. The possible sites of infection were mountainous areas (56.8%), city parks (20.5%), the vicinity of one’s own residence (17.0%), and riversides (5.7%). Eighty-seven chigger mites were collected in Gwanak mountain, one of the suspected infection sites in southern Seoul, and seventy-six (87.4%) of them were identified as Helenicula miyagawai and eight (9.2%) as Leptotrombidium scutellare. Pooled DNA extracted from H. miyagawai mites yielded O. tsutsugamushi Boryong strain. Twenty-six patients from one hospital showed low APACHE II score (3.4 ± 2.7), low complication rate (3.8%), and no hypokalemia. Conclusions We identified the presence of indigenous urban scrub typhus in Seoul, and a subgroup of them had mild clinical features. The chigger mite H. miyagawai infected with O. tsutsugamushi within the city was found. In endemic area, urban scrub typhus needs to be considered as one of the differential febrile diseases and a target for prevention. PMID:26000454

  11. Mercury sorbent delivery system for flue gas

    DOEpatents

    Klunder; ,Edgar B.

    2009-02-24

    The invention presents a device for the removal of elemental mercury from flue gas streams utilizing a layer of activated carbon particles contained within the filter fabric of a filter bag for use in a flue gas scrubbing system.

  12. Chemical-oxidative scrubbing for the removal of hydrogen sulphide from raw biogas: potentials and economics.

    PubMed

    Miltner, M; Makaruk, A; Krischan, J; Harasek, M

    2012-01-01

    In the present work chemical-oxidative scrubbing as a novel method for the desulphurisation of raw biogas is presented with a special focus on the process potentials and economics. The selective absorption of hydrogen sulphide from gas streams containing high amounts of carbon dioxide using caustic solutions is not trivial but has been treated in literature. However, the application of this method to biogas desulphurisation has not been established so far. Based on rigorous experimental work, an industrial-scale pilot plant has been designed, erected and commissioned at a biogas plant with biogas upgrading and gas grid injection in Austria. Data collected from the 12-month monitored operation has been used to elaborate performance as well as economic parameters for the novel desulphurisation method. The proposed technology offers significant operational advantages regarding the degree of automation and the flexibility towards fluctuations in process boundary conditions. Furthermore, the economic assessment revealed the high competitiveness of the chemical-oxidative scrubbing process compared with other desulphurisation technologies with the named advantageous operational behaviour.

  13. Is it time for brushless scrubbing with an alcohol-based agent?

    PubMed

    Gruendemann, B J; Bjerke, N B

    2001-12-01

    The practice of surgical scrubbing in perioperative settings is changing rapidly. This article presents information about eliminating the traditional scrub brush technique and using an alcohol formulation for surgical hand scrubs. Also covered are antimicrobial agents, relevant US Food and Drug Administration classifications, skin and fingernail care, and implementation of changes. The article challenges surgical team members to evaluate a new and different approach to surgical hand scrubbing.

  14. Removal of ethylene and bioaerosol by chlorine dioxide using a chemical scrubbing system in a fruit and vegetable storage facility.

    PubMed

    Chang, Tsu-Hua; Wu, Li-Chun; You, Ya-Ting; Chung, Ying-Chien

    2009-02-15

    Ethylene (C2H4) and bioaerosol are commonly present in the inside atmosphere of postharvest fruit and vegetable storage facilities, which may affect the aging of postharvest fruit and human health. We have assessed the feasibility of chlorine dioxide (ClO2) as the scrubbing solution in a chemical scrubbing tower for simultaneously removing C2H4 and bioaerosol emissions from a gas stream. Parameters such as the ClO2concentration, contact time, and liquid-to-gas (L/G) ratio were examined with the aim of determining the optimal operating conditions. Using the system reported here, the optimal C2H4 removal efficiency was 99.5% when 500 ppm ClO2 was used at a reaction time of 30-60 s under a continuous non-recycle ClO2 flow mode. In terms of C2H4 removal, a greater L/G resulted in a higher C2H4 removal efficiency up to the optimal ratio of 12.5. In terms of the simultaneous removal of C2H4 and bioaerosol, the removal efficiency of C2H4 was 99.2% and those for the bioaersols of Escherichia coli and Staphylococcus aureus were 99.92 and 99.10%, respectively, under a continuous non-recycle flow mode. Our results also indicate that oxidation reduction potential (ORP) can be a valuable indicator for the timing of the replacement of the scrubbing solution in the system under a continuous recycle flow mode. Additional confirmation of the feasibility of the ORP as an indicator of C2H4 and bioaerosol removal in situ was obtained in a 3-month test of our system in continuous recycle flow mode with the periodical replacement of scrubbing solution, ClO2. The removal efficiencies for C2H4, bacterial and fungus aerosol, and total hydrocarbon compounds (THC) were 83.4, 96.8, 96.1, and 76.5%, respectively. Our results prove that ClO2 is an excellent scrubbing solution in the chemical scrubbing tower for the removal of C2H4 emissions and bioaerosol. We demonstrate, for the first time, the feasibility of this system in a fruit and vegetable storage facility. PMID:19132588

  15. BENCH-SCALE EVALUATION OF CALCIUM SORBENTS FOR ACID GAS EMISSION CONTROL

    EPA Science Inventory

    Calcium sorbents for acid gas emission control were evaluated for effectiveness in removing SO2/HCl and SO2/NO from simulated incinerator and boiler flue gases. All tests were conducted in a bench-scale reactor (fixed-bed) simulating fabric filter conditions in an acid gas remova...

  16. Analysis of mycolic acid cleavage products and cellular fatty acids of Mycobacterium species by capillary gas chromatography.

    PubMed

    Lambert, M A; Moss, C W; Silcox, V A; Good, R C

    1986-04-01

    After growth and experimental conditions were established, the mycolic acid cleavage products, constituent fatty acids, and alcohols of representative strains of Mycobacterium tuberculosis, M. smegmatis, M. fortuitum complex, M. kansasii, M. gordonae, and M. avium complex were determined by capillary gas chromatography. Reproducible cleavage of mycolic acid methyl esters to tetracosanoic (24:0) or hexacosanoic (26:0) acid methyl esters was achieved by heating the sample in a high-temperature muffle furnace. The major constituent fatty acids in all species were hexadecanoic (16:0) and octadecenoic (18:1 omega 9-c, oleic) acids. With the exception of M. gordonae, 10-methyloctadecanoic acid was found in all species; moreover, M. gordonae was the only species tested which contained 2-methyltetradecanoic acid. M. kansasii was characterized by the presence of 2,4-dimethyltetradecanoic acid, M. avium complex by 2-eicosanol, and M. tuberculosis by 26:0 mycolic acid cleavage product. The mycolic acid cleavage product in the other five species tested was 24:0. Although a limited number of strains and species were tested, preliminary results indicate that this gas chromatographic method can be used to characterize mycobacterial cultures by their mycolic acid cleavage products and constituent fatty acid and alcohol content. PMID:3084554

  17. Acid Gas Capture Using CO2-Binding Organic Liquids

    SciTech Connect

    Heldebrant, David J.; Koech, Phillip K.; Rainbolt, James E.; Zheng, Feng

    2010-11-10

    Current chemical CO2 scrubbing technology is primarily aqueous alkanolamine based. These systems rapidly bind CO2 (forming water-soluble carbamate and bicarbonate salts) however, the process has serious disadvantages. The concentration of monoethanolamine rarely exceeds 30 wt % due to the corrosive nature of the solution, and this reduces the maximum CO2 volumetric (≤108 g/L) and gravimetric capacity (≤7 wt%) of the CO2 scrubber. The ≤30 wt % loading of ethanolamine also means that a large excess of water must be pumped and heated during CO2 capture and release, and this greatly increases the energy requirements especially considering the high specific heat of water (4 j/g-1K-1). Our approach is to switch to organic systems that chemically bind CO2 as liquid alkylcarbonate salts. Our CO2-binding organic liquids have higher CO2 solubility, lower specific heats, potential for less corrosion and lower binding energies for CO2 than aqueous systems. CO2BOLs also reversibly bind and release mixed sulfur oxides. Furthermore the CO2BOL system can be direct solvent replacements for any solvent based CO2 capture systems because they are commercially available reagents and because they are fluids they would not require extensive process re-engineering.

  18. Scrub Typhus in the Republic of Palau, Micronesia

    PubMed Central

    Kuartei, Stevenson; Togamae, Ishmael; Sengebau, Maireng; Demma, Linda; Nicholson, William; O'Leary, Michael

    2004-01-01

    In October 2001, an outbreak of febrile illness began in the southwest islands group of the Republic of Palau. Through October 2003, a total of 15 southwest islanders experienced fever >39.5°C and abdominal distress, both lasting >7days. Orientia tsutsugamushi, the agent of scrub typhus, was subsequently identified as the cause. PMID:15504273

  19. Retrospective Cognition by Food-Caching Western Scrub-Jays

    ERIC Educational Resources Information Center

    de Kort, S.R.; Dickinson, A.; Clayton, N.S.

    2005-01-01

    Episodic-like memory, the retrospective component of cognitive time travel in animals, needs to fulfil three criteria to meet the behavioral properties of episodic memory as defined for humans. Here, we review results obtained with the cache-recovery paradigm with western scrub-jays and conclude that they fulfil these three criteria. The jays…

  20. Effect of chlorhexidine scrub on postoperative bacterial counts.

    PubMed

    Dahl, J; Wheeler, B; Mukherjee, D

    1990-05-01

    Chlorhexidine surgical scrub was left on the surgeon's hands in 50 orthopedic and vascular surgical procedures to determine whether the number of bacteria on the hands could be decreased postoperatively. After a standard 5-minute scrub, one hand was randomly rinsed prior to gloving; the other was lightly patted with a sterile towel, leaving some foam on the hand. The surgeon then gloved and performed the procedure in the usual manner. After the operation, both hands were immersed in a tryptic soy broth for 30 seconds. The broth was then cultured for bacterial species and number. Cases in which glove puncture occurred were not cultured. The results were analyzed using the Wilcoxon signed-rank test. There were fewer bacterial colonies isolated from the hand coated with chlorhexidine scrub versus the other; this difference was statistically significant (p less than 0.005). There also seemed to be a trend towards higher bacterial counts after longer operations; however, the difference was not significant. Neither surgeon noted any evidence of dermatitis during the study. These results suggest that leaving chlorhexidine scrub on the hands during surgery can lead to lower bacterial counts on the surgeon's hands and less chance of wound contamination should glove puncture occur.

  1. Performance of the prototype gas recirculation system with built-in RGA for INO RPC system

    NASA Astrophysics Data System (ADS)

    Bhuyan, M.; Datar, V. M.; Joshi, A.; Kalmani, S. D.; Mondal, N. K.; Rahman, M. A.; Satyanarayana, B.; Verma, P.

    2012-01-01

    An open loop gas recovery and recirculation system has been developed for the INO RPC system. The gas mixture coming from RPC exhaust is first desiccated by passing through molecular sieve (3 Å+4 Å). Subsequent scrubbing over basic active alumina removes toxic and acidic contaminants. The Isobutane and Freon are then separated by diffusion and liquefied by fractional condensation by cooling up to -26C. A Residual Gas Analyser (RGA) is being used in the loop to study the performance of the recirculation system. The results of the RGA analysis will be discussed.

  2. SO2 SCRUBBING TECHNOLOGIES: A REVIEW

    EPA Science Inventory

    The paper gives results of a review of commercially available flue gas desulfurization (FGD) technologies that have an established record of performance. Data on worldwide FGD applications reflect that wet FGD technologies have been used at most of the installations. Among the ...

  3. Gas chromatography of volatile fatty acids. Method involving separation from biological material by vacuum distillation.

    PubMed

    Tyler, J E; Dibdin, G H

    1975-02-19

    A method is described for the quantitation of C2-C5 volatile fatty acids present in biological tissues. It involved recovery of the acids from their biological matrix by vacuum micro-distillation at room temperature, followed by gas phase separation of aqueous solutions on orthophosphoric acid-modified Phasepak Q columns. The subsequent gas chromatographic procedure resolved iso from normal isomers and showed a linear response for each volatile acid over the range 10-400 ng. There was no evidence of ghosting, isomer peak broadening, or peak tailing. Relative molar response values were shown to be linear with carbon number for all the volatile fatty acids studied.

  4. SO2 SCRUBBING TECHNOLOGIES: A REVIEW

    EPA Science Inventory

    Electricity generating units may use sulfur dioxide (SO2) scrubbers to meet the requirements of Phase II of the Acid Rain S02 Reduction Program. Additionally, the use of scrubbers can result in reduction of mercury emissions. It is timely, therefore, to review the commercially av...

  5. Selection of an acid-gas removal process for an LNG plant

    SciTech Connect

    Stone, J.B.; Jones, G.N.; Denton, R.D.

    1996-12-31

    Acid gas contaminants, such as, CO{sub 2}, H{sub 2}S and mercaptans, must be removed to a very low level from a feed natural gas before it is liquefied. CO{sub 2} is typically removed to a level of about 100 ppm to prevent freezing during LNG processing. Sulfur compounds are removed to levels required by the eventual consumer of the gas. Acid-gas removal processes can be broadly classified as: solvent-based, adsorption, cryogenic or physical separation. The advantages and disadvantages of these processes will be discussed along with design and operating considerations. This paper will also discuss the important considerations affecting the choice of the best acid-gas removal process for LNG plants. Some of these considerations are: the remoteness of the LNG plant from the resource; the cost of the feed gas and the economics of minimizing capital expenditures; the ultimate disposition of the acid gas; potential for energy integration; and the composition, including LPG and conditions of the feed gas. The example of the selection of the acid-gas removal process for an LNG plant.

  6. A Markov decision process for managing habitat for Florida scrub-jays

    USGS Publications Warehouse

    Johnson, Fred A.; Breininger, David R.; Duncan, Brean W.; Nichols, James D.; Runge, Michael C.; Williams, B. Ken

    2011-01-01

    Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrubjays among discrete classes of scrub height (<120 cm or "short"; 120-170 cm or "optimal"; .170 cm or "tall"; and a combination of tall and optimal or "mixed"), and our objective was to calculate a state-dependent management strategy that would maximize the long-term growth rate of the resident scrub-jay population. We used aerial imagery with multistate Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities

  7. Support for Systematic Code Reviews with the SCRUB Tool

    NASA Technical Reports Server (NTRS)

    Holzmann, Gerald J.

    2010-01-01

    SCRUB is a code review tool that supports both large, team-based software development efforts (e.g., for mission software) as well as individual tasks. The tool was developed at JPL to support a new, streamlined code review process that combines human-generated review reports with program-generated review reports from a customizable range of state-of-the-art source code analyzers. The leading commercial tools include Codesonar, Coverity, and Klocwork, each of which can achieve a reasonably low rate of false-positives in the warnings that they generate. The time required to analyze code with these tools can vary greatly. In each case, however, the tools produce results that would be difficult to realize with human code inspections alone. There is little overlap in the results produced by the different analyzers, and each analyzer used generally increases the effectiveness of the overall effort. The SCRUB tool allows all reports to be accessed through a single, uniform interface (see figure) that facilitates brows ing code and reports. Improvements over existing software include significant simplification, and leveraging of a range of commercial, static source code analyzers in a single, uniform framework. The tool runs as a small stand-alone application, avoiding the security problems related to tools based on Web browsers. A developer or reviewer, for instance, must have already obtained access rights to a code base before that code can be browsed and reviewed with the SCRUB tool. The tool cannot open any files or folders to which the user does not already have access. This means that the tool does not need to enforce or administer any additional security policies. The analysis results presented through the SCRUB tool s user interface are always computed off-line, given that, especially for larger projects, this computation can take longer than appropriate for interactive tool use. The recommended code review process that is supported by the SCRUB tool consists of

  8. Impact of elevated CO2 on a Florida Scrub-oak Ecosystems

    SciTech Connect

    Drake, Bert G

    2013-01-01

    Since May of 1996, we have conducted an experiment in Florida Scrub Oak to determine the impact of elevated atmospheric CO2 and climate change on carbon, water, and nutrient cycling in this important terrestrial ecosystem. Florida scrub oak is the name for a collective of species occupying much of the Florida peninsula. The dominant tree species are oaks and the dwarf structure of this community makes it an excellent system in which to test hypotheses regarding the potential capacity of woody ecosystems to assimilate and sequester anthropogenic carbon. Scrub oak is fire dependent with a return cycle of 10-15 years, a time which would permit an experiment to follow the entire cycle. Our site is located on Cape Canaveral at the Kennedy Space Center, Florida. After burning in 1995, we built 16 open top chambers, half of which have been fumigated with pure CO2 sufficient to raise the concentration around the plants to 350 ppm above ambient. In the intervening 10 years we have non destructively measured biomass of shoots and roots, ecosystem gas exchange using chambers and eddy flux, leaf photosynthesis and respiration, soil respiration, and relevant environmental factors such as soil water availability, temperature, light, etc. The overwhelming result from analysis of our extensive data base is that elevated CO2 has had a profound impact on this ecosystem that, overall, has resulted in increased carbon accumulation in plant shoots, roots and litter. Our measurements of net ecosystem gas exchange also indicate that the ecosystem has accumulated carbon much in excess of the increased biomass or soil carbon suggesting a substantial export of carbon through the porous, sandy soil into the water table several meters below the surface. A major discovery is the powerful interaction between the stimulation of growth, photosynthesis, and respiration by elevated CO2 and other environmental factors particularly precipitation and nitrogen. Our measurements focused attention on

  9. Gas chromatographic analysis of total fatty acids in cider.

    PubMed

    Blanco-Gomis, D; Alonso, J J; Cabrales, I M; Abrodo, P A

    2001-03-01

    This paper reports the composition of total fatty acids in an apple beverage, cider. Fatty acids are present in the free or esterified form and contribute to both the flavor and foam properties of cider. Fatty acids were separated and identified as methyl esters by GC-MS, and 12 of these were subsequently determined by GC-FID. The major fatty acids found in cider were caproic, caprylic, capric, and palmitic acid, the saturated acids predominating over the unsaturated ones. The proposed method was applied to 59 ciders from three consecutive harvests (1996, 1997, and 1998), which were made by 19 cider-makers from the region of Asturias (Spain). Linear discriminant analysis of fatty acids in these samples allowed selection of palmitoleic, pentadecanoic, linoleic, myristic, and linolenic acid as the most predictive variables to differentiate ciders made from apples grown in the Asturias region (1997 harvest) and ciders made from apples grown outside this region (1996 and 1998 harvests). PMID:11312846

  10. Severe scrub typhus infection: Clinical features, diagnostic challenges and management

    PubMed Central

    Peter, John Victor; Sudarsan, Thomas I; Prakash, John Anthony J; Varghese, George M

    2015-01-01

    Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay (IFA) for the detection of IgM antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%. PMID:26261776

  11. Severe scrub typhus infection: Clinical features, diagnostic challenges and management.

    PubMed

    Peter, John Victor; Sudarsan, Thomas I; Prakash, John Anthony J; Varghese, George M

    2015-08-01

    Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay (IFA) for the detection of IgM antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%.

  12. Clearcut stand size and scrub-successional bird assemblages

    USGS Publications Warehouse

    Krementz, D.G.; Christie, J.S.

    2000-01-01

    We investigated the effects of clearcut stand size on species richness, reproductive effort, and relative abundance of scrub-successional birds and the entire bird assemblage at the Savannah River Site in South Carolina. We used standardized mist-net grids to mark and recapture birds in clearcuts replanted with longleaf pine (Pinus palustris) in stands of 2 to 57 ha that were two to six years old. Species richness for the entire bird assemblage was not explained by stand size (P = 0.67), stand age (P = 0.95), or the interaction of these two variables (P = 0.90). Similarly, species richness of scrub-successional birds was not explained by stand size (P = 0.63), stand age (P = 0.55), or the interaction of stand size and stand age (P = 0.35). Regressing species richness on clearcut stand size, we found a significant negative relationship between these variables for the entire bird assemblage (P = 0.01) and for scrub-successional birds (P = 0.02). The ratio of juveniles to adults in mist-net samples varied by year (P = 0.04), but neither clearcut size (P = 0.23) nor the interaction of clearcut size and year (P = 0.25) was related to the ratio of juveniles to adults in the sample. We found no relationship between the frequency of capture of any category of birds and stand size (scrub-successional, P = 0.52; woodland, P = 0.77; combined sample, P = 0.55). Neither bird-species richness, reproductive effort, nor relative abundance differed across clearcut stand sizes. Clearcut stand size does not appear to be an important management variable if variation in species richness, reproductive effort, or relative abundance are objectives. We suggest that even-aged forestry is a useful tool for managing birds in the southeastern United States.

  13. Habitat model for the Florida Scrub Jay on John F. Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Breininger, David R.

    1992-01-01

    The Florida Scrub Jay is endemic to Florida. The John F. Kennedy Space Center (KSC) provides habitat for one of the three largest populations of the Florida Scrub Jay. This threatened bird occupies scrub, slash pine flatwoods, disturbed scrub, and coastal strand on KSC. Densities of Florida Scrub Jays were shown to vary with habitat characteristics but not necessarily with vegetation type. Relationships between Florida Scrub Jay densities and habitat characteristics were used to develop a habitat model to provide a tool to compare alternative sites for new facilities and to quantify environmental impacts. This model is being tested using long term demographic studies of colorbanded Florida Scrub Jays. Optimal habitat predicted by the model has greater than or equal to 50 percent of the shrub canopy comprised of scrub oaks, 20-50 percent open space or scrub oak vegetation within 100 m of a ruderal edge, less than or equal to 15 percent pine canopy cover, a shrub height of 120-170 cm, and is greater than or equal to 100 m from a forest. This document reviews life history, social behavior, food, foraging habitat, cover requirements, characteristics of habitat on KSC, and habitat preferences of the Florida Scrub Jay. Construction of the model and its limitations are discussed.

  14. Effect of surgical scrub on microbial population under the fingernails.

    PubMed

    Gross, A; Cutright, D E; D'Alessandro, S M

    1979-09-01

    The effectiveness of two methods of presurgical hand preparation, the 10 minute routine scrub and the 90 second Hydroscrub, in reducing microbial numbers under the fingernails was determined. Bacteriologic cultures of 162 subungual areas of nine subjects revealed prescrub microbial counts of up to 1.9 X 10(5) colony-forming units per area. After the surgical scrub, bacterial concentrations were reduced to a different degree among the persons tested. The mean values of 3.0 X 10(3) to 7.8 X 10(3) colony-forming units immediately after scrub indicated that neither of the two methods tested reduced the microbial population under the fingernails of most persons to acceptable levels. The finding of high postscrub microbial counts under the fingernails is of particular interest and significance in view of the relatively low counts on the fingertips. On the basis of the results of this study, we conclude that degerming of the areas under the fingernails by present methods is not satisfactory. The implication of these findings is discussed.

  15. Scrub Typhus antibody in cynomolgus monkeys (Macaca fascicularis) in Malaysia.

    PubMed

    Heisey, G B; Gan, E; Shirai, A; Groves, M G

    1981-06-01

    Using an indirect immunofluorescence technique, sera from 113 cynomolgus monkeys (Macaca fascicularis), trapped in Peninsular Malaysia, were screened for the presence of antibody to six prototype strains of Rickettsia tsutsugamushi combined into three polyvalent groupings: I--Karp, TA716, and TA763; II--Gilliam; and III--TA678 and TH1817. Fifteen percent (17/113) of the monkeys had antibody titers greater than or equal to 1:50 to one or more of the antigenic groups. Although a titer greater than or equal to 1:150 is generally considered indicative or prior Rickettsia tsutsugamushi infection, we selected a less than 1:25 titer as a conservative standard to insure non-infected animals. Using this criterion, 62 (55%) of the 113 monkeys were accepted for use in scrub typhus studies. The high prevalence of antibody to scrub typhus in the semi-arboreal cynomolgus monkey is in marked contrast to the low prevalence reported in the strictly arboreal silvered leaf monkeys (Presbytis cristatus). The results of this study indicate that cynomolgus monkeys should be rigorously screened for evidence of prior infection before they are included in experimental scrub typhus studies.

  16. Multifunctional acid formation from the gas-phase ozonolysis of beta-pinene.

    PubMed

    Ma, Yan; Marston, George

    2008-10-28

    The gas-phase ozonolysis of beta-pinene was studied in static chamber experiments, using gas chromatography coupled to mass spectrometric and flame ionisation detection to separate and detect products. A range of multifunctional organic acids-including pinic acid, norpinic acid, pinalic-3-acid, pinalic-4-acid, norpinalic acid and OH-pinalic acid-were identified in the condensed phase after derivatisation. Formation yields for these products under systematically varying reaction conditions (by adding different OH radical scavengers and Criegee intermediate scavengers) were investigated and compared with those observed from alpha-pinene ozonolysis, allowing detailed information on product formation mechanisms to be elucidated. In addition, branching ratios for the initial steps of the reaction were inferred from quantitative measurements of primary carbonyl formation. Atmospheric implications of this work are discussed.

  17. Role of mag-enhanced lime scrubbing in the FGD industry

    SciTech Connect

    Babu, M.; College, J.; Smith, K.; Stowe, D.H.

    1997-12-31

    The mag-enhanced lime scrubbing process has been in commercial use in the US since the early 1970`s. At present over 14,000 MW of coal-fired utility plants in the US burning high sulfur coal (2.5--4.0% S) utilize this process with an excellent emission compliance and cost performance record to date. Dravo Lime Company (DLC) being the largest supplier of lime to this industry continues to conduct extensive R and D in this area and provides technical support service to these users. The success of the mag-enhanced lime process is largely attributed to the dual alkali effect of the Mg-Ca ions with a very distinct role for the highly soluble Mg ion in the scrubber liquor. It is well known that the high solubility of the magnesium ions provides alkalinities in the scrubbing liquor far in excess of the limestone systems. As a result of this high alkalinity liquor the mag-lime scrubbers need a much lower liquid to gas ratio, have lower scrubber pressure drop, consume lower parasitic load, are able to handle very high inlet SO{sub 2} concentrations, show little scaling tendency, etc. The scrubbers, recirculation pumps, piping, etc., are much smaller and the systems have lower capital and operating costs over comparable limestone systems. This system typically has a high availability and the process is less severe mechanically on the scrubber, pumps, nozzles, piping than comparable limestone processes. DLC`s patented ThioClear{reg_sign} process is an improvement over the conventional Thiosorbic process in use today. The ThioClear process while providing all of the advantages of the Thiosorbic process uses a nearly clear liquor to scrub and can use an innovative Horizontal Scrubber at gas velocities of up to 7.62--9.14 m/s (25--30 FPS). This process produces an excellent quality gypsum for wall board, cement or other applications and can also produce valuable Mg(OH){sub 2} as by-product. This paper discusses the merits of Thiosorbic/ThioClear processes, innovations with

  18. Effects of ozone and sulfuric acid aerosol on gas trapping in the guinea pig lung

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.

    1986-01-01

    Four groups of 20 guinea pigs were sequentially exposed by inhalation to either air followed by sulfuric acid aerosol, ozone followed by sulfuric acid aerosol, ozone followed by air, or air followed by air to determine whether ozone preexposure sensitizes guinea pigs to the airway constrictive effects of sulfuric acid aerosol. All first exposures to ozone or air were 2 h in duration; all second exposures to sulfuric acid or air were for 1 h. All ozone and sulfuric acid exposures were 0.8 ppm and 12 mg/m3, respectively. Animals were observed for respiratory distress during exposure, and excised lungs were quantitated for trapped gas and wet/dry ratios. None of the guinea pigs developed dyspnea, and wet/dry ratios were not altered. Ozone significantly (p less than 0.05) increased trapped gas volumes, which were 44% (ozone-acid) to 68% (ozone-air) greater than in the air-air group. Trapped gas volume was 23% greater in the ozone-acid group than in the air-acid group, but the difference was not statistically significant (p less than 0.20). Thus, ozone increased gas trapping but did not significantly sensitize guinea pigs to the bronchoconstrictive action of sulfuric acid.

  19. Modeling dry-scrubbing of gaseous HCl with hydrated lime in cyclones with and without recirculation.

    PubMed

    Chibante, Vania G; Fonseca, Ana M; Salcedo, Romualdo R

    2010-06-15

    A mathematical model describing the dry-scrubbing of gaseous hydrogen chloride (HCl) with solid hydrated lime particles (Ca(OH)(2)) was developed and experimentally verified. The model applies to cyclone systems with and without recirculation, where reaction and particle collection occurs in the same processing unit. The Modified Grain Model was selected to describe the behavior of the reaction process and it was assumed that the gas and the solid particles flow in the reactor with a plug flow. In this work, this behavior is approximated by a cascade of N CSTRs in series. Some of the model parameters were estimated by optimization taking into account the experimental results obtained. A good agreement was observed between the experimental results and those predicted by the model, where the main control resistance is the diffusion of the gaseous reactant in the layer of solid product formed. PMID:20185231

  20. Toxic Acid Gas Absorber Design Considerations for Air Pollution Control in Process Industries

    ERIC Educational Resources Information Center

    Manyele, S. V.

    2008-01-01

    This paper analyses the design parameters for an absorber used for removal of toxic acid gas (in particular sulfur dioxide) from a process gas stream for environmental health protection purposes. Starting from the equilibrium data, Henry's law constant was determined from the slope of the y-x diagram. Based on mass balances across the absorber,…

  1. Development of a gas phase source for perfluoroalkyl acids to examine atmospheric sampling methods.

    PubMed

    MacInnis, John J; VandenBoer, Trevor C; Young, Cora J

    2016-06-21

    An inability to produce environmentally relevant gaseous mixing ratios of perfluoroalkyl acids (PFAAs), ubiquitous global contaminants, limits the analytical reliability of atmospheric chemists to make accurate gas and particulate measurements that are demonstrably free of interferences due to sampling artefacts. A gas phase source for PFAAs based on the acid displacement mechanism using perfluoropropionate (PFPrA), perfluorobutanoate (PFBA), perfluorohexanoate (PFHxA), and perfluorooctanoate (PFOA) has been constructed. The displacement efficiency of gas phase perfluorocarboxylic acids (PFCAs) is inversely related to chain length. Decreasing displacement efficiencies for PFPrA, PFBA, PFHxA, and PFOA were 90% ± 20%, 40% ± 10%, 40% ± 10%, 9% ± 4%, respectively. Generating detectable amounts of gas phase perfluorosulfonic acids (PFSAs) was not possible. It is likely that lower vapour pressure and much higher acidity play a role in this lack of emission. PFCA emission rates were not elevated by increasing relative humidity (25%-75%), nor flow rate of carrier gas from 33-111 sccm. Overall, reproducible gaseous production of PFCAs was within the error of the production of hydrochloric acid (HCl) as a displacing acid (±20%) and was accomplished using a dry nitrogen flow of 33 ± 2 sccm. A reproducible mass emission rate of 0.97 ± 0.10 ng min(-1) (n = 8) was observed for PFBA. This is equivalent to an atmospheric mixing ratio of 12 ppmv, which is easily diluted to environmentally relevant mixing ratios of PFBA. Conversely, generating gas phase perfluorononanoic acid (PFNA) by sublimating the solid acid under the same conditions produced a mass emission rate of 2800 ng min(-1), which is equivalent to a mixing ratio of 18 ppthv and over a million times higher than suspected atmospheric levels. Thus, for analytical certification of atmospheric sampling methods, generating gas phase standards for PFCAs is best accomplished using acid displacement under dry conditions

  2. RPC gas recovery by open loop method

    NASA Astrophysics Data System (ADS)

    Joshi, Avinash; Kalmani, S. D.; Mondal, N. K.; Satyanarayana, B.

    2009-05-01

    RPC detectors require to be flushed with small but continuous flow of gas mixture. Dealing with large number of detectors, gas consumption to very large volumes. Gas flow is a running expense and constituent gases are too expensive to be treated as consumables. Exhaust gas mixture from detectors is a potential environmental hazard if discharged directly into the atmosphere. Storage of gases on a large scale also leads to inventory- and safety-related problems. A solution to these problems is the recovery and reuse of exhaust gas mixture from RPC detectors. Close loop method employs recirculation of exhausted gas mixture after purification, analysis and addition of top-up quantities. In open loop method, under consideration here, individual component gases are separated from gas mixture and reused as source. During open loop process, gases liquefiable at low pressures are separated from ones liquefiable at high pressure. The gas phase components within each group are successively separated by either fractional condensation or gravity separation. Gas mixture coming from RPC exhaust is first desiccated by passage through molecular sieve adsorbent type (3A+4A). Subsequent scrubbing over basic activated alumina removes toxic and acidic contaminants such as S 2F 10 produced during corona (arcing) discharge. In the first stage of separation isobutane and freon are concentrated by diffusion and liquefied by fractional condensation by cooling upto -30 °C. Liquefied gases are returned to source tanks. In the second stage of separation, argon and sulphur hexafluoride, the residual gases, are concentrated by settling due to density difference. SF 6 is stored for recovery by condensation at high pressure while argon is further purified by thermal cracking of crossover impurities at 1000 °C followed by wet scrubbing.

  3. Scrub typhus as a possible aetiology of Guillain-Barré syndrome: two cases.

    PubMed

    Lee, M-S; Lee, J-H; Lee, H-S; Chang, H; Kim, Y-S; Cho, K-H; Ahn, S-H; Song, J-H; Yoo, M; Han, J-K; Park, H-Y

    2009-09-01

    Neurological complications of scrub typhus are reported to be rare. Peripheral nervous system involvement has been reported in only one case. We present two cases of Guillan-Barré syndrome (GBS) associated with scrub typhus. In both cases, the findings of an elevated indirect immunofluorescent antibody titer for Orientia tsutsugamushi and nerve conduction study showing sensory-motor polyneuropathy, have led us to believe that scrub typhus could be one of the antecedent illnesses associated with GBS.

  4. [Effect of heparin on acid-base and blood gas parameters].

    PubMed

    Pöge, A W

    1981-09-15

    The influence of blood-heparin-mixing proportion on the acid-base- and blood-gas parameters was measured by means of the blood-gas- automation ABL 1 with the help of 15 test persons. More than 0.15 ml heparin per ml blood, i.e. more than 750 I.U. heparin per ml blood falsify the measuring data and may lead to wrong diagnostic and therapeutic measures. In clinical practice for one 2-ml-blood test only the dead space of the plastic of various producers are characterized by acid-base- and gas values considerable differing from each other. However, they do not influence the blood parameters. By heparin-Weddel (Wales), heparin-Spofa (CSSR), heparin-Richer (Hungary) and heparin-Polfa (Poland) the same acid-base- and blood gas values will be obtained.

  5. Development and implementation of a scrub habitat compensation plan for Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Breininger, David R.; Adrian, Frederic W.; Schaub, Ron; Duncan, Brean W.

    1994-01-01

    Kennedy Space Center (KSC), located on Merritt Island on the east coast of central Florida, is one of three remaining major populations of the Florida Scrub Jay (Aphelocoma coerulescens coerulescens), listed as threatened by the U.S. Fish and Wildlife Service (USFWS) since 1987. Construction of new facilities by the National Aeronautics and Space Administration (NASA) on KSC over the next five years has the potential to impact up to 193 ac (78.1 ha) of Scrub Jay habitat. Under an early consultation process with the Endangered Species Office of the USFWS, NASA agreed to a compensation plan for loss of Scrub Jay habitat. The compensation plan required NASA to restore or create scrub on KSC at a 2:1 ratio for that lost. The compensation plan emphasized restoration of scrub habitat that is of marginal or declining suitability to Scrub Jays because it has remained unburned. Although prescribed burning has been conducted by the USFWS Merritt Island National Wildlife Refuge (MINWR) for more than ten years, significant areas of scrub remain unburned because they have been excluded from fire management units or because landscape fragmentation and a period of fire suppression allowed scrub to reach heights and diameters that are fire resistant. For such areas, mechanical cutting followed by prescribed burning was recommended for restoration. A second part of the restoration plan is an experimental study of scrub reestablishment (i.e., creation) on abandoned, well drained agricultural sites by planting scrub oaks and other scrub plants. The compensation plan identified 260 ac (105 ha) of scrub restoration in four areas and a 40 ac (16 ha) scrub creation site. Monitoring of restoration sites required under the plan included: establishing permanent vegetation sample transects before treatment and resampling annually for ten years after treatment, and color banding Scrub Jays to determine territories prior to treatment followed by monitoring reproductive success and survival for

  6. Study of an ammonia-based wet scrubbing process in a continuous flow system

    SciTech Connect

    Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B.; Luebke, David R.; Damodaran, Krishnan

    2013-01-01

    A continuous gas and liquid flow, regenerative scrubbing process for CO{sub 2} capture was demonstrated at the bench-scale level. An aqueous ammonia-based solution captures CO{sub 2} from simulated flue gas in an absorber and releases a nearly pure stream of CO{sub 2} in the regenerator. After the regeneration, the solution of ammonium compounds is recycled to the absorber. The design of a continuous flow unit was based on earlier exploratory results from a semi-batch reactor, where a CO{sub 2} and N{sub 2} simulated flue gas mixture flowed through a well-mixed batch of ammonia-based solution. During the semi-batch tests, the solution was cycled between absorption and regeneration steps to measure the carrying capacity of the solution at various initial ammonia concentrations and temperatures. Consequentially, a series of tests were conducted on the continuous unit to observe the effect of various parameters on CO{sub 2} removal efficiency and regenerator effectiveness within the flow system. The parameters that were studied included absorber temperature, regenerator temperature, initial NH{sub 3} concentration, simulated flue gas flow rate, liquid solvent inventory in the flow system, and height of the packed-bed absorber. From this testing and subsequent testing, ammonia losses from both the absorption and regeneration steps were quantified, and attempts were made to maintain steady state during operations. Implications of experimental results with respect to process design are discussed.

  7. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, S.L.; Lee, E.K.L.; Friesen, D.T.; Kelly, D.J.

    1989-04-25

    There is disclosed a composite immobilized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorus or sulfur atom, and having a boiling point of at least 100 C and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation. 3 figs.

  8. Gas separation by composite solvent-swollen membranes

    DOEpatents

    Matson, Stephen L.; Lee, Eric K. L.; Friesen, Dwayne T.; Kelly, Donald J.

    1989-01-01

    There is disclosed a composite immobulized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorous or sulfur atom, and having a boiling point of at least 100.degree. C. and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation.

  9. Abnormal incorporation of amino acids into the gas hydrate crystal lattice.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Lee, Bo Ram; Ahn, Docheon; Lee, Kun-Hong

    2014-12-28

    Gas hydrates are crystalline ice-like solid materials enclosing gas molecules inside. The possibility of the presence of gas hydrates with amino acids in the universe is of interest when revealing the potential existence of life as they are evidence of a source of water and organic precursors, respectively. However, little is known about how they can naturally coexist, and their crystallization behavior would become far more complex as both crystallize with formation of hydrogen bonds. Here, we report abnormal incorporation of amino acids into the gas hydrate crystal lattice that is contrary to the generally accepted crystallization mode, and this resulted in lattice distortion and expansion. The present findings imply the potential for their natural coexistence by sharing the crystal lattice, and will be helpful for understanding the role of additives in the gas hydrate crystallization.

  10. Gas-Phase Structures of Ketene and Acetic Acid from Acetic Anhydride Using Very-High-Temperature Gas Electron Diffraction.

    PubMed

    Atkinson, Sandra J; Noble-Eddy, Robert; Masters, Sarah L

    2016-03-31

    The gas-phase molecular structure of ketene has been determined using samples generated by the pyrolysis of acetic anhydride (giving acetic acid and ketene), using one permutation of the very-high-temperature (VHT) inlet nozzle system designed and constructed for the gas electron diffraction (GED) apparatus based at the University of Canterbury. The gas-phase structures of acetic anhydride, acetic acid, and ketene are presented and compared to previous electron diffraction and microwave spectroscopy data to show improvements in data extraction and manipulation with current methods. Acetic anhydride was modeled with two conformers, rather than a complex dynamic model as in the previous study, to allow for inclusion of multiple pyrolysis products. The redetermined gas-phase structure of acetic anhydride (obtained using the structure analysis restrained by ab initio calculations for electron diffraction method) was compared to that from the original study, providing an improvement on the description of the low vibrational torsions compared to the dynamic model. Parameters for ketene and acetic acid (both generated by the pyrolysis of acetic anhydride) were also refined with higher accuracy than previously reported in GED studies, with structural parameter comparisons being made to prior experimental and theoretical studies. PMID:26916368

  11. Gas-Phase Structures of Ketene and Acetic Acid from Acetic Anhydride Using Very-High-Temperature Gas Electron Diffraction.

    PubMed

    Atkinson, Sandra J; Noble-Eddy, Robert; Masters, Sarah L

    2016-03-31

    The gas-phase molecular structure of ketene has been determined using samples generated by the pyrolysis of acetic anhydride (giving acetic acid and ketene), using one permutation of the very-high-temperature (VHT) inlet nozzle system designed and constructed for the gas electron diffraction (GED) apparatus based at the University of Canterbury. The gas-phase structures of acetic anhydride, acetic acid, and ketene are presented and compared to previous electron diffraction and microwave spectroscopy data to show improvements in data extraction and manipulation with current methods. Acetic anhydride was modeled with two conformers, rather than a complex dynamic model as in the previous study, to allow for inclusion of multiple pyrolysis products. The redetermined gas-phase structure of acetic anhydride (obtained using the structure analysis restrained by ab initio calculations for electron diffraction method) was compared to that from the original study, providing an improvement on the description of the low vibrational torsions compared to the dynamic model. Parameters for ketene and acetic acid (both generated by the pyrolysis of acetic anhydride) were also refined with higher accuracy than previously reported in GED studies, with structural parameter comparisons being made to prior experimental and theoretical studies.

  12. Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidities, photoelectron spectra, and computations on tyrosine, p-hydroxybenzoic acid, and their conjugate bases.

    PubMed

    Tian, Zhixin; Wang, Xue-Bin; Wang, Lai-Sheng; Kass, Steven R

    2009-01-28

    Deprotonation of tyrosine in the gas phase was found to occur preferentially at the phenolic site, and the conjugate base consists of a 70:30 mixture of phenoxide and carboxylate anions at equilibrium. This result was established by developing a chemical probe for differentiating these two isomers, and the presence of both ions was confirmed by photoelectron spectroscopy. Equilibrium acidity measurements on tyrosine indicated that deltaG(acid)(o) = 332.5 +/- 1.5 kcal mol(-1) and deltaH(acid)(o) = 340.7 +/- 1.5 kcal mol(-1). Photoelectron spectra yielded adiabatic electron detachment energies of 2.70 +/- 0.05 and 3.55 +/- 0.10 eV for the phenoxide and carboxylate anions, respectively. The H/D exchange behavior of deprotonated tyrosine was examined using three different alcohols (CF3CH2OD, C6H5CH2OD, and CH3CH2OD), and incorporation of up to three deuterium atoms was observed. Two pathways are proposed to account for these results, and all of the experimental findings are supplemented with B3LYP/aug-cc-pVDZ and G3B3 calculations. In addition, it was found that electrospray ionization of tyrosine from a 3:1 (v/v) CH3OH/H2O solution using a commercial source produces a deprotonated [M-H]- anion with the gas-phase equilibrium composition rather than the structure of the ion that exists in aqueous media. Electrospray ionization from acetonitrile, however, leads largely to the liquid-phase (carboxylate) structure. A control molecule, p-hydroxybenzoic acid, was found to behave in a similar manner. Thus, the electrospray conditions that are employed for the analysis of a compound can alter the isomeric composition of the resulting anion.

  13. Self-Scrubbing Coal -- an integrated approach to clean air

    SciTech Connect

    Harrison, K.E.

    1997-12-31

    Carefree Coal is coal cleaned in a proprietary dense-media cyclone circuit, using ultrafine magnetite slurries, to remove noncombustible material, including up to 90% of the pyritic sulfur. Deep cleaning alone, however, cannot produce a compliance fuel from coals with high organic sulfur contents. In these cases, Self-Scrubbing Coal will be produced. Self-Scrubbing Coal is produced in the same manner as Carefree Coal except that the finest fraction of product from the cleaning circuit is mixed with limestone-based additives and briquetted. The reduced ash content of the deeply-cleaned coal will permit the addition of relatively large amounts of sorbent without exceeding boiler ash specifications or overloading electrostatic precipitators. This additive reacts with sulfur dioxide (SO{sub 2}) during combustion of the coal to remove most of the remaining sulfur. Overall, sulfur reductions in the range of 80--90% are achieved. After nearly 5 years of research and development of a proprietary coal cleaning technology coupled with pilot-scale validation studies of this technology and pilot-scale combustion testing of Self-Scrubbing Coal, Custom Coals Corporation organized a team of experts to prepare a proposal in response to DOE`s Round IV Program Opportunity Notice for its Clean Coal Technology Program under Public Law 101-121 and Public Law 101-512. The main objective of the demonstration project is the production of a coal fuel that will result in up to 90% reduction in sulfur emissions from coal-fired boilers at a cost competitive advantage over other technologies designed to accomplish the same sulfur emissions and over naturally occurring low sulfur coals.

  14. Spatiotemporal Dynamics of Scrub Typhus Transmission in Mainland China, 2006-2014

    PubMed Central

    Hu, Wen-Biao; Haque, Ubydul; Weppelmann, Thomas A.; Wang, Yong; Liu, Yun-Xi; Li, Xin-Lou; Sun, Hai-Long; Sun, Yan-Song; Clements, Archie C. A.; Li, Shen-Long; Zhang, Wen-Yi

    2016-01-01

    Background Scrub typhus is endemic in the Asia-Pacific region including China, and the number of reported cases has increased dramatically in the past decade. However, the spatial-temporal dynamics and the potential risk factors in transmission of scrub typhus in mainland China have yet to be characterized. Objective This study aims to explore the spatiotemporal dynamics of reported scrub typhus cases in mainland China between January 2006 and December 2014, to detect the location of high risk spatiotemporal clusters of scrub typhus cases, and identify the potential risk factors affecting the re-emergence of the disease. Method Monthly cases of scrub typhus reported at the county level between 2006 and 2014 were obtained from the Chinese Center for Diseases Control and Prevention. Time-series analyses, spatiotemporal cluster analyses, and spatial scan statistics were used to explore the characteristics of the scrub typhus incidence. To explore the association between scrub typhus incidence and environmental variables panel Poisson regression analysis was conducted. Results During the time period between 2006 and 2014 a total of 54,558 scrub typhus cases were reported in mainland China, which grew exponentially. The majority of cases were reported each year between July and November, with peak incidence during October every year. The spatiotemporal dynamics of scrub typhus varied over the study period with high-risk clusters identified in southwest, southern, and middle-eastern part of China. Scrub typhus incidence was positively correlated with the percentage of shrub and meteorological variables including temperature and precipitation. Conclusions The results of this study demonstrate areas in China that could be targeted with public health interventions to mitigate the growing threat of scrub typhus in the country. PMID:27479297

  15. Evaluation of gas cooling for pressurized phosphoric acid fuel cell stacks

    NASA Technical Reports Server (NTRS)

    Farooque, M.; Skok, A. J.; Maru, H. C.; Kothmann, R. E.; Harry, R. W.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas cooling has already been demonstrated in atmospheric pressure stacks. This paper presents theoretical and experimental investigation of gas cooling for pressurized PAFC. Two approaches to gas cooling, Distributed Gas Cooling (DIGAS) and Separated Gas Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  16. Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

    NASA Technical Reports Server (NTRS)

    Faroque, M.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  17. Acid gas absorption in aqueous solutions of mixed amines

    SciTech Connect

    Rinker, E.B.; Ashour, S.S.; Sandall, O.C.

    1996-12-31

    A mass transfer model has been developed to describe the rate of absorption (or desorption) of H{sub 2}S and CO{sub 2} in aqueous blends of a tertiary and a secondary or a primary amine. The model is based on penetration theory, and all significant chemical reactions are incorporated in the model. The reactions are taken to be reversible, with reactions involving only a proton transfer considered to be at equilibrium. The particular amines studied in this research were methyldiethanolamine (MDEA), a tertiary amine, and diethanolamine (DEA), a secondary amine. Key physicochemical data needed in the model, such as diffusion coefficients, kinetic rate constants, and gas solubilities, were measured. Experimental absorption rates of CO{sub 2} and H{sub 2}S were measured in a model gas-liquid contacting device and were compared with model predictions. Experiments were carried out for single amine solutions (both MDEA and DEA) and for amine blends.

  18. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    EPA Science Inventory

    Abstract

    The need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  19. Control of scale in flue gas scrubbers

    SciTech Connect

    Thomas, P.A.; Dewitt-Dick, D.B.

    1987-06-02

    This patent describes a flue gas desulfurization system in which sulfur dioxide-containing flue gas is passed in countercurrent flow with an aqueous calcium-bearing scrubbing liquor whereby the sulfur dioxide is removed from the flue gas by being absorbed by the scrubbing liquor and converted to calcium sulfite and/or calcium sulfate. The improvement of minimizing the formation of calcium scale on the surfaces of the system comprises maintaining in the scrubbing liquor about 0.1-25 ppm of a 1:1 diisobutylene-maleic anhydride copolymer having an average molecular weight of 11000. The copolymer is incorporated in the scrubbing liquor as a 10-15% aqueous dispersion.

  20. Formation routes of interstellar glycine involving carboxylic acids: possible favoritism between gas and solid phase.

    PubMed

    Pilling, Sergio; Baptista, Leonardo; Boechat-Roberty, Heloisa M; Andrade, Diana P P

    2011-11-01

    Despite the extensive search for glycine (NH₂CH₂COOH) and other amino acids in molecular clouds associated with star-forming regions, only upper limits have been derived from radio observations. Nevertheless, two of glycine's precursors, formic acid and acetic acid, have been abundantly detected. Although both precursors may lead to glycine formation, the efficiency of reaction depends on their abundance and survival in the presence of a radiation field. These facts could promote some favoritism in the reaction pathways in the gas phase and solid phase (ice). Glycine and these two simplest carboxylic acids are found in many meteorites. Recently, glycine was also observed in cometary samples returned by the Stardust space probe. The goal of this work was to perform theoretical calculations for several interstellar reactions involving the simplest carboxylic acids as well as the carboxyl radical (COOH) in both gas and solid (ice) phase to understand which reactions could be the most favorable to produce glycine in interstellar regions fully illuminated by soft X-rays and UV, such as star-forming regions. The calculations were performed at four different levels for the gas phase (B3LYP/6-31G*, B3LYP/6-31++G**, MP2/6-31G*, and MP2/6-31++G**) and at MP2/6-31++G** level for the solid phase (ice). The current two-body reactions (thermochemical calculation) were combined with previous experimental data on the photodissociation of carboxylic acids to promote possible favoritism for glycine formation in the scenario involving formic and acetic acid in both gas and solid phase. Given that formic acid is destroyed more in the gas phase by soft X-rays than acetic acid is, we suggest that in the gas phase the most favorable reactions are acetic acid with NH or NH₂OH. Another possible reaction involves NH₂CH₂ and COOH, one of the most-produced radicals from the photodissociation of acetic acid. In the solid phase, we suggest that the reactions of formic acid with NH

  1. Gas Phase Structure of Amino Acids: La-Mb Studies

    NASA Astrophysics Data System (ADS)

    Mata, I. Pena S.; Sanz, M. E.; Vaquero, V.; Cabezas, C.; Perez, C.; Blanco, S.; López, J. C.; Alonso, J. L.

    2009-06-01

    Recent improvements in our laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectrometer such as using Laval-type nozzles and picoseconds Nd:YAG lasers (30 to 150 ps) have allowed a major step forward in the capabilities of this experimental technique as demonstrated by the last results in serine cysteine and threonine^a for which seven, six and seven conformers have been respectively identified. Taking advantage of these improvements we have investigated the natural amino acids metionine, aspartic and glutamic acids and the γ-aminobutyric acid (GABA) with the aim of identify and characterize their lower energy conformers. Searches in the rotational spectra have lead to the identification of seven conformers of metionine, six and five of aspartic and glutamic acids, respectively, and seven for the γ-aminobutyric. These conformers have been unambiguously identified by their spectroscopic constants. In particular the ^{14}N nuclear quadrupole coupling constants, that depend heavily on the orientation of the amino group with respect to the principal inertial axes of the molecule, prove to be a unique tool to distinguish unambigously between conformations with similar rotational constants. For the γ-aminobutyric acid two of the seven observed structures are stablized by an intramolecular interaction n-π*. Two new conformers of proline have been identified together with the two previously observed. J. L. Alonso, C. Pérez, M. E. Sanz, J. C. López, S. Blanco, Phys.Chem.Chem.Phys., 2009, 11, 617. D. B. Atkinson, M. A. Smith, Rev. Sci. Instrum. 1995, 66, 4434 S. Blanco, M. E. Sanz, J. C. López, J. L. Alonso, Proc. Natl. Acad. Sci. USA2007, 104, 20183. M. E. Sanz, S. Blanco, J. C. López, J. L. Alonso, Angew. Chem. Int. Ed.,2008, 120, 6312. A. Lesarri, S. Mata, E. J. Cocinero, S. Blanco, J.C. López, J. L. Alonso, Angew. Chem. Int. Ed. , 2002, 41, 4673

  2. Ductwork and chimney modifications for utilization of improved FGD scrubbing capacity

    SciTech Connect

    Fang, S.J.; Chhabra, S.J.; Gullaksen, D.J.; Cassidy, S.

    1996-10-01

    Tampa Electric Company`s (TECO) Big Bend Station located southwest of Tampa, Florida, consists of four coal-fired units totaling 1,822 MW. The 475-MW Unit 4, which began operation in 1985, operates with a balanced draft system and is equipped with a wet limestone forced-oxidation flue gas desulfurization (FGD) system. Units 1 through 3, which operate with forced draft systems, are not equipped with FGD systems and, consequently, are subject to the Phase 1 Clean Air Act Amendments of 1990. TECO initiated studies to determine the most effective program for achieving environmental compliance for Units 1 through 3 and, based on these studies, developed an innovative idea for using the improved FGD scrubbing capacity of Unit 4 to treat the flue gas from Unit 3. On June 20, 1995, TECO successfully implemented this idea when it diverted Unit 3 flue gas to the Unit 4 scrubber. The project required modifications to the Unit 4 scrubber, as well as modifications to the draft system controls, ductwork, continuous emissions monitoring systems, and chimneys of both Units 3 and 4. The purpose of this paper is to describe the unique aspects of the ductwork and chimney modifications that were implemented on the project.

  3. Multi-component removal in flue gas by aqua ammonia

    DOEpatents

    Yeh, James T.; Pennline, Henry W.

    2007-08-14

    A new method for the removal of environmental compounds from gaseous streams, in particular, flue gas streams. The new method involves first oxidizing some or all of the acid anhydrides contained in the gas stream such as sulfur dioxide (SO.sub.2) and nitric oxide (NO) and nitrous oxide (N.sub.2O) to sulfur trioxide (SO.sub.3) and nitrogen dioxide (NO.sub.2). The gas stream is subsequently treated with aqua ammonia or ammonium hydroxide which captures the compounds via chemical absorption through acid-base or neutralization reactions. The products of the reactions can be collected as slurries, dewatered, and dried for use as fertilizers, or once the slurries have been dewatered, used directly as fertilizers. The ammonium hydroxide can be regenerated and recycled for use via thermal decomposition of ammonium bicarbonate, one of the products formed. There are alternative embodiments which entail stoichiometric scrubbing of nitrogen oxides and sulfur oxides with subsequent separate scrubbing of carbon dioxide.

  4. Epidemiology of scrub typhus in eastern Taiwan, 2000-2004.

    PubMed

    Lee, Yeong-Sheng; Wang, Pei-Hua; Tseng, Shu-Jen; Ko, Ching-Fen; Teng, Hwa-Jen

    2006-08-01

    The epidemiology of scrub typhus in eastern Taiwan was studied by analyzing the data from the CDC Web reporting system. A total of 1,396 cases with 403 confirmed cases were reported in the period of 2000 to 2004. The cases were commonly found in all counties with the highest number in Yuli Township, Hualien County (53 cases) and Taitung City, Taitung County (40 cases). Monthly changes in the number of cases showed epidemic periods in the spring with a peak in May, and again in the fall, with an October-November peak. The occurrence of disease varied with age, gender, and occupation. Our results showed that the infection rates in the elderly (50-69 years old), males (62.8%), and farmers (25.6%) were higher than those in other age groups, females, and other occupations. Five major clinical symptoms, fever, headache, eschar, rash, and lymphadenopathy, were observed in 90.1, 61.9, 23.1, 21.6, and 10.7% of the cases, respectively. Almost 90% (89.3%) of the cases showed 1-3 clinical symptoms and some showed 4-5 symptoms (10%). Only one patient with no symptoms (0.8%) was found. This paper reports the status of scrub typhus in eastern Taiwan, and suggests that a health education program could train individuals to self-recognize the disease symptoms. PMID:16936341

  5. Gas chromatographic organic acid profiling analysis of brandies and whiskeys for pattern recognition analysis.

    PubMed

    Park, Y J; Kim, K R; Kim, J H

    1999-06-01

    An efficient gas chromatographic profiling and pattern recognition method is described for brandy and whiskey samples according to their organic acid contents. It involves solid-phase extraction of organic acids using Chromosorb P with subsequent conversion to stable tert-butyldimethylsilyl derivatives for the direct analysis by capillary column gas chromatography and gas chromatography-mass spectrometry. A total of 12 organic acids were reproducibly identified in liquor samples (1 mL). When the GC profiles were simplified to their retention index spectra, characteristic patterns were obtained for each liquor sample as well as for each group average. Stepwise discriminant analysis provided star symbols characteristic for each liquor sample and group average. As expected, canonical discriminant analysis correctly classified 23 liquor samples studied into two groups of either brandy or whiskey.

  6. Gas chromatographic organic acid profiling analysis of brandies and whiskeys for pattern recognition analysis.

    PubMed

    Park, Y J; Kim, K R; Kim, J H

    1999-06-01

    An efficient gas chromatographic profiling and pattern recognition method is described for brandy and whiskey samples according to their organic acid contents. It involves solid-phase extraction of organic acids using Chromosorb P with subsequent conversion to stable tert-butyldimethylsilyl derivatives for the direct analysis by capillary column gas chromatography and gas chromatography-mass spectrometry. A total of 12 organic acids were reproducibly identified in liquor samples (1 mL). When the GC profiles were simplified to their retention index spectra, characteristic patterns were obtained for each liquor sample as well as for each group average. Stepwise discriminant analysis provided star symbols characteristic for each liquor sample and group average. As expected, canonical discriminant analysis correctly classified 23 liquor samples studied into two groups of either brandy or whiskey. PMID:10794629

  7. Collection and analysis of organic acids in exhaust gas. Comparison of different methods

    NASA Astrophysics Data System (ADS)

    Zervas, E.; Montagne, X.; Lahaye, J.

    This paper reports the development of a specific method to identify organic acids in exhaust gases. The organic acids are collected in two impingers containing liquids (pure water or Na 2CO 3 1% aqueous solution) and four cartridges containing solids (silica, fluorisil, alumina B and alumina N). Once collected, the acids are eluted of the solids by a hot water stream. These traps performances, in terms of organic acids collection and elution efficiency, are evaluated and compared. Two sources are used to produce the gas flow containing organic acids: one generates a flow whose concentration is known and stable, the other produces organic acids among other combustion products. For eluted solutions analysis, two methods are used: isocratic ionic chromatography/conductivity detection and GC/FID. Their efficiency in separating 10 aliphatic acids are compared. Their characteristics such as detection limits, detection linearity, repeatability and possible interferences with other components found in exhaust gases are determined. The stability of the organic acids solutions is also studied. Lastly, the use of these methods is illustrated by the analysis of the gas-phase organic acids exhausted by a spark ignition and by a diesel engine.

  8. A randomized crossover trial to decrease bacterial contamination on hospital scrubs.

    PubMed

    Boutin, Mallory A; Thom, Kerri A; Zhan, Min; Johnson, J Kristie

    2014-11-01

    Healthcare worker attire may become contaminated with pathogenic organisms during a normal shift. We performed a randomized crossover study to assess whether treatment with an antimicrobial coating would decrease bacterial contamination on scrubs. Thirty percent of all scrubs were contaminated; there was no difference in the rate of contamination between the intervention and control groups.

  9. A Spatiotemporal Database to Track Human Scrub Typhus Using the VectorMap Application

    PubMed Central

    Kelly, Daryl J.; Foley, Desmond H.; Richards, Allen L.

    2015-01-01

    Scrub typhus is a potentially fatal mite-borne febrile illness, primarily of the Asia-Pacific Rim. With an endemic area greater than 13 million km2 and millions of people at risk, scrub typhus remains an underreported, often misdiagnosed febrile illness. A comprehensive, updatable map of the true distribution of cases has been lacking, and therefore the true risk of disease within the very large endemic area remains unknown. The purpose of this study was to establish a database and map to track human scrub typhus. An online search using PubMed and the United States Armed Forces Pest Management Board Literature Retrieval System was performed to identify articles describing human scrub typhus cases both within and outside the traditionally accepted endemic regions. Using World Health Organization guidelines, stringent criteria were used to establish diagnoses for inclusion in the database. The preliminary screening of 181 scrub typhus publications yielded 145 publications that met the case criterion, 267 case records, and 13 serosurvey records that could be georeferenced, describing 13,739 probable or confirmed human cases in 28 countries. A map service has been established within VectorMap (www.vectormap.org) to explore the role that relative location of vectors, hosts, and the pathogen play in the transmission of mite-borne scrub typhus. The online display of scrub typhus cases in VectorMap illustrates their presence and provides an up-to-date geographic distribution of proven scrub typhus cases. PMID:26678263

  10. Engineering Porous Organic Cage Crystals with Increased Acid Gas Resistance.

    PubMed

    Zhu, Guanghui; Hoffman, Christopher D; Liu, Yang; Bhattacharyya, Souryadeep; Tumuluri, Uma; Jue, Melinda L; Wu, Zili; Sholl, David S; Nair, Sankar; Jones, Christopher W; Lively, Ryan P

    2016-07-25

    Both known and new CC3-based porous organic cages are prepared and exposed to acidic SO2 in vapor and liquid conditions. Distinct differences in the stability of the CC3 cages exist depending on the chirality of the diamine linkers used. The acid catalyzed CC3 degradation mechanism is probed via in situ IR and a degradation pathway is proposed and supported with computational results. CC3 crystals synthesized with racemic mixtures of diaminocyclohexane exhibited enhanced stability compared to CC3-R and CC3-S. Confocal fluorescent microscope images reveal that the stability difference in CC3 species originates from an abundance of mesoporous grain boundaries in CC3-R and CC3-S, allowing facile access of aqueous SO2 throughout the crystal, promoting decomposition. These grain boundaries are absent from CC3 crystals made with racemic linkers. PMID:27253350

  11. Gas Phase Electronic Spectroscopy of 5-FLUOROSALICYLIC Acid.

    NASA Astrophysics Data System (ADS)

    Young, Justin W.; Fleisher, Adam J.; Pratt, David W.

    2010-06-01

    Methyl salicylate and its derivatives have generated large amounts of interest due to the possibility of intramolecular proton transfer in their electronically excited states (ESPT). Here, the excited state dynamics of 5-fluorosalicylic acid and its dimer will be discussed within the context of their vibrationally and rotationally resolved electronic spectra. Stark effect studies of the latter permit identification of specific conformers of 5FSA. However, some species exhibit broadened spectra, whereas others do not, suggesting a species-specific ESPT reaction. thanks

  12. TECHNICAL AND OPERATING SUPPORT FOR PILOT DEMONSTRATION OF MORPHYSORB ACID GAS REMOVAL PROCESS

    SciTech Connect

    Nagaraju Palla; Dennis Leppin

    2003-06-30

    GTI and Krupp Uhde have been jointly developing advanced technology for removing high concentrations of acid gas from high-pressure natural gas for over a decade. This technology, the Morphysorb{reg_sign} process, based on N-formyl and N-acetyl morpholine mixtures, has now been tested in a large-scale facility and this paper presents preliminary results from acceptance testing at that facility. Earlier publications have discussed the bench-scale and pilot plant work that led up to this important milestone. The site was Duke Energy's new Kwoen sour gas upgrader near Chetwynd B.C., Canada. This facility has a nameplate capacity of 300 MMscfd of sour natural gas. The objective of the Morphysorb process at this site was to remove 33 MMscfd of acid gas (H{sub 2}S and CO{sub 2}) for reinjection downhole. This represents about half the acid gas present in the feed to the plant. In so doing, proportionately more of the plant ''sales'' gas, which is sent for final processing at the nearby Pine River plant, can be sent down the line without coming up against the sulfur removal capacity limits of Pine River plant, than could with other solvents that were evaluated. Other benefits include less loss of methane downhole with the rejected acid gas and lower circulation and recycle compression horsepower than with competitive solvents. On the downside, the process is expected to have higher solvent vaporization losses than competitive solvents, but this is a comparatively minor drawback when weighed against the value of the benefits. These benefits (and drawbacks) were developed into quantitative ''acceptance'' criteria, which will determine if the solvent will continue to be used at the site and for award of monetary bonuses to the process developer (GTI).

  13. TECHNICAL AND OPERATING SUPPORT FOR PILOT DEMONSTRATION OF MORPHYSORB ACID GAS REMOVAL PROCESS

    SciTech Connect

    Nagaraju Palla; Dennis Leppin

    2003-09-30

    GTI and Krupp Uhde have been jointly developing advanced technology for removing high concentrations of acid gas from high-pressure natural gas for over a decade. This technology, the Morphysorb{reg_sign} process, based on N-formyl and N-acetyl morpholine mixtures, has now been tested in a large-scale facility and this paper presents preliminary results from acceptance testing at that facility. Earlier publications have discussed the bench-scale and pilot plant work that led up to this important milestone. The site was Duke Energy's new Kwoen sour gas upgrader near Chetwynd B.C., Canada. This facility has a nameplate capacity of 300 MMscfd of sour natural gas. The objective of the Morphysorb process at this site was to remove 33 MMscfd of acid gas (H{sub 2}S and CO{sub 2}) for reinjection downhole. This represents about half the acid gas present in the feed to the plant. In so doing, proportionately more of the plant ''sales'' gas, which is sent for final processing at the nearby Pine River plant, can be sent down the line without coming up against the sulfur removal capacity limits of Pine River plant, than could with other solvents that were evaluated. Other benefits include less loss of methane downhole with the rejected acid gas and lower circulation and recycle compression horsepower than with competitive solvents. On the downside, the process is expected to have higher solvent vaporization losses than competitive solvents, but this is a comparatively minor drawback when weighed against the value of the benefits. These benefits (and drawbacks) were developed into quantitative ''acceptance'' criteria, which will determine if the solvent will continue to be used at the site and for award of monetary bonuses to the process developer (GTI).

  14. Gas Phase Measurements of Mono-Fluoro Acids and the Dimer of 3-FLUORO-BENZOIC Acid

    NASA Astrophysics Data System (ADS)

    Daly, Adam M.; Carey, Spencer J.; Pejlovas, Aaron M.; Li, Kexin; Kang, Lu; Kukolich, Stephen G.

    2016-06-01

    The gas phase homodimer of 3-fluorobenzoic acid was detected and the spectra showed evidence of proton tunneling. Experimental rotational constants are A(0^+)= 1151.8(5), B(0^+)=100.3(5), C(0^+)= 87.64(3) MHz and A(0^-)=1152.2(5), B(0^-)= 100.7(5), C(0^-)=88.85(3) MHz for the two ground vibrational states split by the proton tunneling motion. The tunneling splitting (ΔE) is approximately 560 MHz. This homodimer appears to be the largest carboxylic acid dimer observed with F-T microwave spectroscopy. Additionally, the microwave spectra of the mono-fluoro-benozic acids, (2-fluoro, 3-floro and 4-fluoro) benzoic acid have been measured in the frequency range of 4-14 GHz using a pulsed beam Fourier Transform microwave spectrometer. Measured rotational transition lines were assigned and fit using a rigid rotor Hamiltonian. Assignments were made for 3 conformers of 2-fluorobenzoic acid, 2 conformers of 3-fluorobenzoic acid and 1 conformer of 4-fluorobenzoic acid. Supported by the NSF CHE-1057796

  15. Gas phase measurements of mono-fluoro-benzoic acids and the dimer of 3-fluoro-benzoic acid

    NASA Astrophysics Data System (ADS)

    Daly, Adam M.; Carey, Spencer J.; Pejlovas, Aaron M.; Li, Kexin; Kang, Lu; Kukolich, Stephen G.

    2015-04-01

    The microwave spectrum of the mono-fluoro-benzoic acids, 2-fluoro-, 3-fluoro-, and 4-fluoro-benzoic acid have been measured in the frequency range of 4-14 GHz using a pulsed beam Fourier transform microwave spectrometer. Measured rotational transition lines were assigned and fit using a rigid rotor Hamiltonian. Assignments were made for 3 conformers of 2-fluorobenzoic acid, 2 conformers of 3-fluorobenzoic acid, and 1 conformer of 4-fluorobenzoic acid. Additionally, the gas phase homodimer of 3-fluorobenzoic acid was detected, and the spectra showed evidence of proton tunneling. Experimental rotational constants are A(0+) = 1151.8(5), B(0+) = 100.3(5), C(0+) = 87.64(3) MHz and A(0-) = 1152.2(5), B(0-) = 100.7(5), C(0-) = 88.85(3) MHz for the two ground vibrational states split by the proton tunneling motion. The tunneling splitting (ΔE) is approximately 560 MHz. This homodimer appears to be the largest carboxylic acid dimer observed with F-T microwave spectroscopy.

  16. Gas phase measurements of mono-fluoro-benzoic acids and the dimer of 3-fluoro-benzoic acid

    SciTech Connect

    Daly, Adam M.; Carey, Spencer J.; Pejlovas, Aaron M.; Li, Kexin; Kukolich, Stephen G.; Kang, Lu

    2015-04-14

    The microwave spectrum of the mono-fluoro-benzoic acids, 2-fluoro-, 3-fluoro-, and 4-fluoro-benzoic acid have been measured in the frequency range of 4-14 GHz using a pulsed beam Fourier transform microwave spectrometer. Measured rotational transition lines were assigned and fit using a rigid rotor Hamiltonian. Assignments were made for 3 conformers of 2-fluorobenzoic acid, 2 conformers of 3-fluorobenzoic acid, and 1 conformer of 4-fluorobenzoic acid. Additionally, the gas phase homodimer of 3-fluorobenzoic acid was detected, and the spectra showed evidence of proton tunneling. Experimental rotational constants are A(0{sup +}) = 1151.8(5), B(0{sup +}) = 100.3(5), C(0{sup +}) = 87.64(3) MHz and A(0{sup −}) = 1152.2(5), B(0{sup −}) = 100.7(5), C(0{sup −}) = 88.85(3) MHz for the two ground vibrational states split by the proton tunneling motion. The tunneling splitting (ΔE) is approximately 560 MHz. This homodimer appears to be the largest carboxylic acid dimer observed with F-T microwave spectroscopy.

  17. Brushes and picks used on nails during the surgical scrub to reduce bacteria: a randomised trial.

    PubMed

    Tanner, J; Khan, D; Walsh, S; Chernova, J; Lamont, S; Laurent, T

    2009-03-01

    Though brushes are no longer used on the hands and forearms during the surgical scrub, they are still widely used on the nails. The aim of this study was to determine whether nail picks and nail brushes are effective in providing additional decontamination during a surgical hand scrub. A total of 164 operating department staff were randomised to undertake one of the following three surgical hand-scrub protocols: chlorhexidine only; chlorhexidine and a nail pick; or chlorhexidine and a nail brush. Bacterial hand sampling was conducted before and 1h after scrubbing using a modified version of the glove juice method. No statistically significant differences in bacterial numbers were found between any two of the three intervention groups. Nail brushes and nail picks used during surgical hand scrubs do not decrease bacterial numbers and are unnecessary.

  18. Determination of Free Fatty Acids and Triglycerides by Gas Chromatography Using Selective Esterification Reactions

    SciTech Connect

    Kail, Brian W; Link, Dirk D; Morreale, Bryan D

    2012-11-01

    A method for selectively determining both free fatty acids (FFA) and triacylglycerides (TAGs) in biological oils was investigated and optimized using gas chromatography after esterification of the target species to their corresponding fatty acid methyl esters (FAMEs). The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs. Complete conversion of both free acids and glycerides to corresponding FAMEs was found to require more rigorous reaction conditions involving heating to 120°C for up to 2 h. Method validation was provided using gas chromatography–flame ionization detection, gas chromatography–mass spectrometry, and liquid chromatography–mass spectrometry. The method improves on existing methods because it allows the total esterified lipid to be broken down by FAMEs contributed by FFA compared to FAMEs from both FFA and TAGs. Single and mixed-component solutions of pure fatty acids and triglycerides, as well as a sesame oil sample to simulate a complex biological oil, were used to optimize the methodologies. Key parameters that were investigated included: HCl-to-oil ratio, temperature and reaction time. Pure free fatty acids were found to esterify under reasonably mild conditions (10 min at 50°C with a 2.1:1 HCl to fatty acid ratio) with 97.6 ± 2.3% recovery as FAMEs, while triglycerides were largely unaffected under these reaction conditions. The optimized protocol demonstrated that it is possible to use esterification reactions to selectively determine the free acid content, total lipid content, and hence, glyceride content in biological oils. This protocol also allows gas chromatography analysis of FAMEs as a more ideal analyte than glyceride species in their native state.

  19. Preparation of sphingolipid fatty acid methyl esters for determination by gas-liquid chromatography.

    PubMed

    MacGee, J; Williams, M G

    1981-01-30

    Sphingolipid fatty acids are first converted to a mixture of free acids and their n-butyl esters by heating the specimen at 85 degree C in aqueous butanolic hydrogen chloride; the butyl esters are then saponified with methanolic potassium hydroxide. After acidification and extraction into hexane, the fatty acids are extracted into a very small volume of aqueous trimethyl(m-trifluorotolyl)ammonium hydroxide (TMTFTH), injection of an aliquot of the TMTFTH extract into the gas chromatograph yields the fatty acid methyl esters by pyrolytic methylation of the quaternary ammonium salts of the fatty acids. The preparation of a specimen ready for the gas--liquid chromatographic (GLC) analysis with quantitative recovery of the sphingolipid fatty acids can be accomplished in less than 2 h. By comparison, none of a number of well-accepted techniques for the release of sphingomyelin fatty acids by hydrolysis or methanolysis released the fatty acids quantitatively in less than 3 h, and all required additional manipulations before GLC analysis. PMID:7217267

  20. Ammonia gas sensing behavior of tanninsulfonic acid doped polyaniline-TiO₂ composite.

    PubMed

    Bairi, Venu Gopal; Bourdo, Shawn E; Sacre, Nicolas; Nair, Dev; Berry, Brian C; Biris, Alexandru S; Viswanathan, Tito

    2015-10-16

    A highly active tannin doped polyaniline-TiO₂ composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO₂ in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO₂. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO₂ and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO₂ composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

  1. Strategies for utilizing ferrous*EDTA chelate as an additive in combined SO sub 2 /NO sub x aqueous scrubbing systems

    SciTech Connect

    Medelsohn, M.H.; Harkness, J.B.L.

    1990-01-01

    Ferrous*EDTA chelate has been found to be an effective scrubbing agent for nitric oxide gas. A major problem encountered in its practical application is that that ferrous ion oxidizes in solution to the ferric species, thus decreasing the NO{sub x} removal of the scrubbing solution. This paper discusses three strategies for overcoming this problem. Dow Chemical has studied the use of an electrolytic cell to reduce ferric ions to the corresponding ferrous species. Workers at the Pittsburgh Energy Technology Center have studied in situ bisulfite reduction of ferric ions to ferrous ions at elevated temperature (70{degrees}C). We have studied NO{sub x} removal from simulated flue gas mixtures under various oxidizing conditions and have found that addition of an organic, polyphenolic compound to an aqueous scrubbing solution containing Fe(II)*EDTA leads to a sustained NO{sub x} removal significantly higher than was found without the secondary additive. The improved performance of Fe(II)*EDTA under these conditions is attributed to the known capabilities of these organic compounds to both inhibit oxidation by dissolved oxygen and to rapidly reduce any ferric ions back to the original ferrous species. Advantages of a NO{sub x}-control process based upon an additive in an SO{sub 2}-control chemistry over serial processes are discussed. 10 refs., 6 figs.

  2. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  3. Determination of Atmospheric Hydroxyl Radical by Liquid Phase Scrubbing and High Performance Liquid Chromatography.

    NASA Astrophysics Data System (ADS)

    Chen, Xiaohui

    A new in situ method for determining atmospheric hydroxyl radical (OH) was developed. This method is based on liquid phase scrubbing technique and high performance liquid chromatography (LPS-HPLC). The sampling system employs glass bubblers to trap atmospheric OH into a buffered solution containing the chemical probe, salicylic acid (o-hydroxybenzoic acid, OHBA). The reaction of OHBA with OH produces a stable fluorescent product, 2,5-dihydroxybenzoic acid (2,5-DHBA), which is determined by reverse phase HPLC and fluorescence detection. The atmospheric OH concentration ( (OH)) is inferred from the resulting 2,5-DHBA amount in the aqueous scrubbing solution, fraction of 2,5-DHBA in the products, air sampling flow rate, sampling time, local pressure and temperature, etc. HPLC separation efficiency and fluorescence detection sensitivity for 2,5-DHBA have been studied. The results indicate that: the reagent blank can be controlled by suitable recrystallization; pH affects both separation and detection processes; the fluorometer should be adjusted to reach its highest signal-to-noise ratio by light source selection, flow cell size selection, wavelength selection, etc. Preliminary column switch experiments reveal the possibility to automate the whole sampling and detection system to enhance the temporal resolution. During an intercomparison of tropospheric OH measurement techniques at the Caribou site, CO (relatively unpolluted air) in Fall 1993, overlapping data were obtained with long path absorption and ion-assisted coupled with MS methods. LPS -HPLC day-time (OH) s, which range from {< }10^6 to 6times10 ^6 radicals/cm^3, agree well with those derived from the other two methods, especially the latter. LPS-HPLC (OH) depends linearly on the combined effects of solar flux, ozone and water vapor, however, it has a nonlinear dependence on NO _{x} and hydrocarbons. These results are consistent with that predicted from photochemical models. Experimental results and model

  4. Effects of DDT on bird population of scrub forest

    USGS Publications Warehouse

    Robbins, C.S.; Stewart, R.E.

    1949-01-01

    An oil spray of DDT was applied at the rate of five pounds per acre to a 90-acre tract of 5-year-old scrub and sapling growth at Beltsville, Maryland. Bird population studies were carried on in a 30-acre plot at the center of the sprayed area, and in a 30-acre check area of the same habitat one-half mile away. Of the five commonest species in the sprayed area, the Maryland yellowthroat, prairie warbler, and house wren were reduced 80 per cent, and the red-eyed towhee was apparently reduced 35 per cent; while no appreciable change in the numbers of yellow-breasted chats was noted. The total decrease for the five commonest species, which represented 77 per cent of the original population, was 65 per cent.

  5. Hydrophobic amino acids as a new class of kinetic inhibitors for gas hydrate formation

    PubMed Central

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Lee, Bo Ram; Park, Da-Hye; Han, Kunwoo; Lee, Kun-Hong

    2013-01-01

    As the foundation of energy industry moves towards gas, flow assurance technology preventing pipelines from hydrate blockages becomes increasingly significant. However, the principle of hydrate inhibition is still poorly understood. Here, we examined natural hydrophobic amino acids as novel kinetic hydrate inhibitors (KHIs), and investigated hydrate inhibition phenomena by using them as a model system. Amino acids with lower hydrophobicity were found to be better KHIs to delay nucleation and retard growth, working by disrupting the water hydrogen bond network, while those with higher hydrophobicity strengthened the local water structure. It was found that perturbation of the water structure around KHIs plays a critical role in hydrate inhibition. This suggestion of a new class of KHIs will aid development of KHIs with enhanced biodegradability, and the present findings will accelerate the improved control of hydrate formation for natural gas exploitation and the utilization of hydrates as next-generation gas capture media. PMID:23938301

  6. Hydrophobic amino acids as a new class of kinetic inhibitors for gas hydrate formation

    NASA Astrophysics Data System (ADS)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Lee, Bo Ram; Park, Da-Hye; Han, Kunwoo; Lee, Kun-Hong

    2013-08-01

    As the foundation of energy industry moves towards gas, flow assurance technology preventing pipelines from hydrate blockages becomes increasingly significant. However, the principle of hydrate inhibition is still poorly understood. Here, we examined natural hydrophobic amino acids as novel kinetic hydrate inhibitors (KHIs), and investigated hydrate inhibition phenomena by using them as a model system. Amino acids with lower hydrophobicity were found to be better KHIs to delay nucleation and retard growth, working by disrupting the water hydrogen bond network, while those with higher hydrophobicity strengthened the local water structure. It was found that perturbation of the water structure around KHIs plays a critical role in hydrate inhibition. This suggestion of a new class of KHIs will aid development of KHIs with enhanced biodegradability, and the present findings will accelerate the improved control of hydrate formation for natural gas exploitation and the utilization of hydrates as next-generation gas capture media.

  7. Keto acid profiling analysis as ethoxime/tert-butyldimethylsilyl derivatives by gas chromatography-mass spectrometry.

    PubMed

    Nguyen, Duc-Toan; Lee, Gwang; Paik, Man-Jeong

    2013-01-15

    Organic acids, including keto acids, are key intermediates of central pathways in cellular metabolism. In this study, a comprehensive and reliable method was developed and optimized for the simultaneous measurement of 17 keto acids in various biological samples. The keto acids were converted to solvent extractable forms by ethoximation followed by tert-butyldimethylsilylation for direct analysis by gas chromatography-mass spectrometry in selected ion monitoring mode. The proposed method was precise (0.05-8.3, % RSD) and accurate (-10.5 to 5.3, % RE) with low limit of detection (0.01-0.5ng/mL) and good linearity (r>0.995) in the range of 0.01-5.0μg/mL. This was suitable for profiling analysis of targeted keto acids in human plasma, urine and rat brain tissue.

  8. The basic chemistry of gas recombination in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Nelson, Robert

    2001-01-01

    Oxygen-recombination chemistry has been wedded to traditional lead-acid battery technology to produce so-called sealed, or valve-regulated, lead-acid products. Early attempts to incorporate recombination into lead-acid batteries were unsuccessful because of excessive cost, size, and/or complexity, and none were effectively commercialized. Over the past 20 years, recombination systems have been developed and are under going an extensive program of definition and refinement at many battery companies. This paper presents the basic chemistry of oxygen recombination in lead-acid cells and briefly compares it with the more highly developed nickel-cadmium system, which also operates on the oxygen cycle. Aspects of gas and thermal management relevant to valve-regulated lead-acid batteries are discussed in some detail.

  9. Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

    PubMed

    Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

    2016-03-01

    A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples.

  10. Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides

    PubMed Central

    Prentice, Boone M.; Gilbert, Joshua D.; Stutzman, John R.; Forrest, William P.; McLuckey, Scott A.

    2012-01-01

    Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [N-cyclohexyl-N′-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT). Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities. PMID:23208744

  11. TECHNICAL AND OPERATING SUPPORT FOR PILOT DEMONSTRATION OF MORPHYSORB ACID GAS REMOVAL PROCESS

    SciTech Connect

    Nagaraju Palla; Dennis Leppin

    2004-02-01

    Over the past 14 years, the Gas Technology Institute and jointly with Uhde since 1997 developing Morphysorb{reg_sign} a new physical solvent-based acid gas removal process. Based on extensive laboratory, bench, pilot-plant scale experiments and computer simulations, DEGT Gas Transmission Company, Canada (DEGT) has chosen the process for use at its Kwoen processing facility near Chetwynd, British Columbia, Canada as the first commercial application for the Morphysorb process. DOE co-funded the development of the Morphysorb process in various stages of development. DOE funded the production of this report to ensure that the results of the work would be readily available to potential users of the process in the United States. The Kwoen Plant is designed to process 300 MMscfd of raw natural gas at 1,080-psia pressure. The sour natural gas contains 20 to 25 percent H{sub 2}S and CO{sub 2}. The plant reduces the acid gas content by about 50% and injects the removed H{sub 2}S and CO{sub 2} into an injection well. The Kwoen plant has been operating since August 2002. Morphysorb{reg_sign} is a physical solvent-based process used for the bulk removal of CO{sub 2} and/or H{sub 2}S from natural gas and other gaseous streams. The solvent consists of N-Formyl morpholine and other morpholine derivatives. This process is particularly effective for high-pressure and high acid-gas applications and offers substantial savings in investment and operating cost compared to competitive physical solvent-based processes. GTI and DEGT first entered into an agreement in 2002 to test the Morphysorb process at their Kwoen Gas Treating Plant in northern BC. The process is operating successfully without any solvent related problems and has between DEGTC and GTI. As of December 2003, about 90 Bcf of sour gas was processed. Of this about 8 Bcf of acid gas containing mainly H{sub 2}S and CO{sub 2} was injected back into the depleted reservoir and 82 Bcf sent for further processing at DEGTC's Pine

  12. Regeneration of an aqueous solution from an acid gas absorption process by matrix stripping

    DOEpatents

    Rochelle, Gary T.; Oyenekan, Babatunde A.

    2011-03-08

    Carbon dioxide and other acid gases are removed from gaseous streams using aqueous absorption and stripping processes. By replacing the conventional stripper used to regenerate the aqueous solvent and capture the acid gas with a matrix stripping configuration, less energy is consumed. The matrix stripping configuration uses two or more reboiled strippers at different pressures. The rich feed from the absorption equipment is split among the strippers, and partially regenerated solvent from the highest pressure stripper flows to the middle of sequentially lower pressure strippers in a "matrix" pattern. By selecting certain parameters of the matrix stripping configuration such that the total energy required by the strippers to achieve a desired percentage of acid gas removal from the gaseous stream is minimized, further energy savings can be realized.

  13. An acid-gas removal system for upgrading subquality natural gas

    SciTech Connect

    Palla, N.; Lee, A.L.; Leppin, D.; Shoemaker, H.D.; Hooper, H.M.; Emmrich, G.; Moore, T.F.

    1996-09-01

    The objective of this project is to develop systems to reduce the cost of treating subquality natural gas. Based on over 1,000 laboratory experiments on vapor-liquid equilibria and mass transfer and simulation studies, the use of N-Formyl Morpholine as a solvent together with structured packings has the following advantages: high capacity for H{sub 2}S and CO{sub 2} removal; little or no refrigeration required; less loss of hydrocarbons (CH{sub 4}, C{sub 2}-C{sub 6}); and dehydration potential. To verify these findings and to obtain additional data base for scale-up, a field test unit capable of processing 1MMSCF/d of natural gas has been installed at the Shell Western E and P Inc. (SWEPI) Fandango processing plant site. The results of the testing at the Fandango site will be presented when available.

  14. Sustainable production of acrylic acid: alkali-ion exchanged beta zeolite for gas-phase dehydration of lactic acid.

    PubMed

    Yan, Bo; Tao, Li-Zhi; Liang, Yu; Xu, Bo-Qing

    2014-06-01

    Gas-phase dehydration of lactic acid (LA) to acrylic acid (AA) was investigated over alkali-exchanged β zeolite (M(x)Na(1-x)β, M=Li(+), K(+), Rb(+), or Cs(+)) of different exchange degrees (x). The reaction was conducted under varying conditions to understand the catalyst selectivity for AA production and trends of byproduct formation. The nature and exchange degree of M(+) were found to be critical for the acid-base properties and catalytic performance of the exchanged zeolite. K(x)Na(1-x)β of x=0.94 appeared to be the best performing catalyst whereas Li(x)Na(1-x)β and Naβ were the poorest in terms of AA selectivity and yield. The AA yield as high as 61 mol % (selectivity: 64 mol %) could be obtained under optimized reaction conditions for up to 8 h over the best performing K0.94Na0.06β. The acid and base properties of the catalysts were probed, respectively by temperature-programmed desorption (TPD) of adsorbed NH3 and CO2, and were related to the electrostatic potentials of the alkali ions in the zeolite, which provided a basis for the discussion of the acid-base catalysis for sustainable AA formation from LA.

  15. Low temperature dry scrubbing reaction kinetics and mechanisms, Volume 1. Final report, September 1, 1991--August 31, 1992

    SciTech Connect

    Prudich, M.E.; Sampson, K.J.; Reddy, S.N.; Maldei, M.; Ben-Said, L.

    1992-10-01

    Dry scrubbing that takes place after the air preheater (<350{degree}F) is the mode of operation that is of primary interest to this research project. At the relatively low temperatures that occur in this region of operation the rate of the gas-solid reaction that drives SO{sub 2} capture in the convective (800 to 1200{degree}F) and the combustion (1600 to 2400{degree}F) zones is too slow to be significant. The presence of significant amounts of either liquid-phase or vapor-phase water is required in order to mediate SO{sub 2} capture and to produce reasonable capture rates. A mathematical process model describing the cross-flow, moving-bed Limestone Emission Control (LEC) process has been formulated. This process model incorporates the resistance-in-series SO{sub 2} capture kinetic model described in the Project Year {number_sign}1 final report. The kinetic model formulated during Project Year {number_sign}1 pointed to limestone solubility and rate of solubilization as being key factors in determining the rate of SO{sub 2} capture in wetted limestone (LEC) scrubbing systems. In Project Year {number_sign}2, limestone solubilities and rates of solubilization are being determined for a suite of Ohio limestones.

  16. Scrub typhus islands in the Taiwan area and the association between scrub typhus disease and forest land use and farmer population density: geographically weighted regression

    PubMed Central

    2013-01-01

    Background The Taiwan area comprises the main island of Taiwan and several small islands located off the coast of the Southern China. The eastern two-thirds of Taiwan are characterized by rugged mountains covered with tropical and subtropical vegetation. The western region of Taiwan is characterized by flat or gently rolling plains. Geographically, the Taiwan area is diverse in ecology and environment, although scrub typhus threatens local human populations. In this study, we investigate the effects of seasonal and meteorological factors on the incidence of scrub typhus infection among 10 local climate regions. The correlation between the spatial distribution of scrub typhus and cultivated forests in Taiwan, as well as the relationship between scrub typhus incidence and the population density of farm workers is examined. Methods We applied Pearson’s product moment correlation to calculate the correlation between the incidence of scrub typhus and meteorological factors among 10 local climate regions. We used the geographically weighted regression (GWR) method, a type of spatial regression that generates parameters disaggregated by the spatial units of analysis, to detail and map each regression point for the response variables of the standardized incidence ratio (SIR)-district scrub typhus. We also applied the GWR to examine the explanatory variables of types of forest-land use and farm worker density in Taiwan in 2005. Results In the Taiwan Area, scrub typhus endemic areas are located in the southeastern regions and mountainous townships of Taiwan, as well as the Pescadore, Kinmen, and Matou Islands. Among these islands and low-incidence areas in the central western and southwestern regions of Taiwan, we observed a significant correlation between scrub typhus incidence and surface temperature. No similar significant correlation was found in the endemic areas (e.g., the southeastern region and the mountainous area of Taiwan). Precipitation correlates positively

  17. A New Population Estimate for the Florida Scrub Jay on Merritt Island National Wildlife Refuge

    NASA Technical Reports Server (NTRS)

    Breininger, David R.

    1989-01-01

    The variable circular plot method was used to sample avifauna within different vegetation types determined from aerial imagery. The Florida Scrub Jay (Aphelocoma coerulescens coerulescens) population was estimated to range between 1,415 and 3,603 birds. Approximately half of the scrub and slash pine habitat appeared to be unused by Florida Scrub Jay, probably because the slash pine cover was too dense or the oak cover was too sparse. Results from the study suggest that the entire state population may be much lower than believed because the size of two of the three largest populations may have been overestimated.

  18. Scrub Typhus Presenting with Bilateral Lateral Rectus Palsy in A Female

    PubMed Central

    Mishra, Jaya; Barman, Bhupen; Mondal, Sumantro; Sivam, Rondeep Kumar Nath

    2016-01-01

    Scrub typhus, a rickettsial disease is endemic in several parts of India usually presenting with acute symptoms. Fever, maculopapular rash, eschar, history of tick exposure and supportive diagnostic tests usually leads to diagnosis. Scrub typhus should be included in the differential diagnosis in occasions when a patient presents with fever with or without eschar and isolated cranial nerve palsy. Here we are reporting a case of Scrub typhus who presented with fever and altered sensorium of short duration, eschar formation and bilateral lateral rectus palsy. Patient was treated with doxycycline with complete reversal of neurodeficit. PMID:27190871

  19. A comparison of the gas phase acidities of phospholipid headgroups: experimental and computational studies.

    PubMed

    Thomas, Michael C; Mitchell, Todd W; Blanksby, Stephen J

    2005-06-01

    Proton-bound dimers consisting of two glycerophospholipids with different headgroups were prepared using negative ion electrospray ionization and dissociated in a triple quadrupole mass spectrometer. Analysis of the tandem mass spectra of the dimers using the kinetic method provides, for the first time, an order of acidity for the phospholipid classes in the gas phase of PE < PA < PG < PS < PI. Hybrid density functional calculations on model phospholipids were used to predict the absolute deprotonation enthalpies of the phospholipid classes from isodesmic proton transfer reactions with phosphoric acid. The computational data largely support the experimental acidity trend, with the exception of the relative acidity ranking of the two most acidic phospholipid species. Possible causes of the discrepancy between experiment and theory are discussed and the experimental trend is recommended. The sequence of gas phase acidities for the phospholipid headgroups is found to (1) have little correlation with the relative ionization efficiencies of the phospholipid classes observed in the negative ion electrospray process, and (2) correlate well with fragmentation trends observed upon collisional activation of phospholipid [M - H](-) anions. PMID:15907707

  20. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

    SciTech Connect

    Lee, Y.I.

    1986-01-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/ greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.

  1. Activated carbon cleanup of the acid gas feed to Claus sulfur plants

    SciTech Connect

    Harruff, L.G.; Bushkuhl, S.J.

    1996-12-31

    This paper presents the details of a recently developed novel process using activated carbon to remove hydrocarbon contaminants from the acid gas feed to Claus sulfur recovery units. Heavy hydrocarbons, particularly benzene, toluene and xylene (BTX) have been linked to coke formation and catalyst deactivation in Claus converters. This deactivation results in reduced sulfur recovery and increased sulfur emissions from these plants. This effect is especially evident in split flow Claus plants which bypass some of the acid gas feed stream around the initial combustion step because of a low hydrogen sulfide concentration. This new clean-up process was proven to be capable of removing 95% of the BTX and other C{sub 6}{sup +} hydrocarbons from acid gas over a wide range of actual plant conditions. Following the adsorption step, the activated carbon was easily regenerated using low pressure steam. A post regeneration drying step using plant fuel gas also proved beneficial. This technology was extensively pilot tested in Saudi Aramco`s facilities in Saudi Arabia. Full scale commercial units are planned for two plants in the near future with the first coming on-line in 1997. The process described here represents the first application of activated carbon in this service, and a patent has been applied for. The paper will discuss the pilot plant results and the issues involved in scale-up to commercial size.

  2. Identification of individual acids in a commercial sample of naphthenic acids from petroleum by two-dimensional comprehensive gas chromatography/mass spectrometry.

    PubMed

    Rowland, Steven J; West, Charles E; Scarlett, Alan G; Jones, David

    2011-06-30

    The identification of most individual members of the complex mixtures of carboxylic acids found in petroleum ('naphthenic acids') has eluded chemists for over a century; they remain unresolved by conventional gas chromatographic methods. Recently, however, we successfully used two-dimensional comprehensive gas chromatography/mass spectrometry to identify numerous individual diamondoid acids in the naphthenic acids of oil sands process water (OSPW). We have now applied the same methods to a study of a mixture of commercially available naphthenic acids originally refined from petroleum. The results confirm that OSPW and refined petroleum contain very different distributions of acids, as noted previously, although some of the diamondoid acids recently identified in OSPW were detectable in both. Rather, two-dimensional comprehensive gas chromatography/time-of-flight mass spectrometry (GCxGC/ToF-MS) of the methyl esters of the petroleum acids and of numerous acids synthesised for comparison showed that the former comprised mainly C(8-18) straight-chain, methyl-branched, acyclic isoprenoid, cyclohexyl and isomeric octahydropentalene, perhydroindane and perhydronaphthalene (decalin) acids. Some of the latter bicyclic acids occurred as both the non-alkyl-substituted isomers and the bicyclic ethanoic and propanoic acids. Also present in minor quantities was a range of phenyl carboxylic and substituted phenyl alkanoic acids, and traces of non-acids, including trimethylnaphthalenes, again identified by comparison with the synthesised compounds. These results represent some of the first identifications of multiple individual naphthenic acids in commercial mixtures originating from petroleum and provide a basis for future studies of the petroleum geochemistry, toxicities and environmental impacts of the acids. Furthermore, characterisation of the acids will be important for improving the understanding of the role of naphthenic acids in petroleum engineering, particularly for

  3. Gas-phase structures and thermochemistry of neutral histidine and its conjugated acid and base.

    PubMed

    Riffet, Vanessa; Bouchoux, Guy

    2013-04-28

    Extensive exploration of the conformational space of neutral, protonated and deprotonated histidine has been conducted at the G4MP2 level. Theoretical protonation and deprotonation thermochemistry as well as heats of formation of gaseous histidine and its ionized forms have been calculated at the G4 level considering either the most stable conformers or an equilibrium population of conformers at 298 K. These theoretical results were compared to evaluated experimental determinations. Recommended proton affinity and protonation entropy deduced from these comparisons are PA(His) = 980 kJ mol(-1) and ΔpS(His) ∼ 0 J mol(-1) K(-1), thus leading to a gas-phase basicity value of GB(His) = 947.5 kJ mol(-1). Similarly, gas phase acidity parameters are ΔacidH(o)(His) = 1373 kJ mol(-1), ΔacidS(His) ∼ 10 J mol(-1) K(-1) and ΔacidG(o)(His) = 1343 kJ mol(-1). Computed G4 heats of formation values are equal to -290, 265 and -451 kJ mol(-1) for gaseous neutral histidine and its protonated and deprotonated forms, respectively. The present computational data correct, and complete, previous thermochemical parameter estimates proposed for gas-phase histidine and its acido-basic properties.

  4. Identification of 19 phthalic acid esters in dairy products by gas chromatography with mass spectrometry.

    PubMed

    Wu, Pinggu; Cai, Chenggang; Yang, Dajin; Wang, Liyuan; Zhou, Yan; Shen, Xianghong; Ma, Bingjie; Tang, Jun

    2015-01-01

    A detection method for 19 kinds of phthalic acid ester compounds analyzed by n-hexane/ether/acetonitrile 1:7:8 v/v/v mixed solvent extraction, quick, easy, cheap, effective, rugged, and safe purification and internal standard method of quantitative gas chromatography with mass spectrometry was established. This method can effectively remove interfering materials, such as lipids, fatty acids, and pigments, from dairy products. The 19 kinds of phthalic acid ester compounds were within a 0.025-0.2 mg/kg range, the recovery rate was 65.2-125.7%, relative standard deviation was 7.9-15.4% (n = 6), and the limit of detection was 0.005-0.02 mg/kg. Concentrations of the 19 kinds of phthalic acid ester compounds ranged between 0.01 and 0.12 mg/kg in ten dairy materials and 20 dairy products. The established method is simple, rapid, accurate, and highly sensitive.

  5. Molecular structures of benzoic acid and 2-hydroxybenzoic acid, obtained by gas-phase electron diffraction and theoretical calculations.

    PubMed

    Aarset, Kirsten; Page, Elizabeth M; Rice, David A

    2006-07-20

    The structures of benzoic acid (C6H5COOH) and 2-hydroxybenzoic acid (C6H4OHCOOH) have been determined in the gas phase by electron diffraction using results from quantum chemical calculations to inform restraints used on the structural parameters. Theoretical methods (HF and MP2/6-311+G(d,p)) predict two conformers for benzoic acid, one which is 25.0 kJ mol(-1) (MP2) lower in energy than the other. In the low-energy form, the carboxyl group is coplanar with the phenyl ring and the O-H group eclipses the C=O bond. Theoretical calculations (HF and MP2/6-311+G(d,p)) carried out for 2-hydroxybenzoic acid gave evidence for seven stable conformers but one low-energy form (11.7 kJ mol(-1) lower in energy (MP2)) which again has the carboxyl group coplanar with the phenyl ring, the O-H of the carboxyl group eclipsing the C=O bond and the C=O of the carboxyl group oriented toward the O-H group of the phenyl ring. The effects of internal hydrogen bonding in 2-hydroxybenzoic acid can be clearly observed by comparison of pertinent structural parameters between the two compounds. These differences for 2-hydroxybenzoic acid include a shorter exocyclic C-C bond, a lengthening of the ring C-C bond between the substituents, and a shortening of the carboxylic single C-O bond. PMID:16836466

  6. Scrub typhus infection presenting as acute heart failure: A case report and systematic review of literature of cardiopulmonary involvement in scrub typhus infection.

    PubMed

    Ray, Animesh; Nangia, Vivek; Chatterji, R S; Dalal, Navin

    2016-01-01

    We describe a middle aged previoulsy healthy female patient who presented with clinical features suggestive of acute heart failure. Investigations revealed very high NT pro-BNP, right heart enlargement, bilateral pulmonary alveolar edema and bilateral pleural effusion. In view of falling platelet counts and exudative pleural effusion inflammatory/infective causes were considered. Her Weil Felix test was strongly positive and IgM for scrub typhus also returned positive. She was started on doxycycline to which there was dramatic improvement. Thus in this case scrub typhus infection presented as acute right heart failure and the cause seemed elusive at the outset. We also systematically reviewed the existing literature on cardio-pulmonary manifestations of scrub typhus infection. PMID:27578941

  7. Ammonia Gas Sensing Behavior of Tanninsulfonic Acid Doped Polyaniline-TiO2 Composite

    PubMed Central

    Bairi, Venu Gopal; Bourdo, Shawn E.; Sacre, Nicolas; Nair, Dev; Berry, Brian C.; Biris, Alexandru S.; Viswanathan, Tito

    2015-01-01

    A highly active tannin doped polyaniline-TiO2 composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO2 in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO2. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO2 and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO2 composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported. PMID:26501291

  8. View of STS-1 Launch Day MCC activities ending in a scrub on the mission

    NASA Technical Reports Server (NTRS)

    1981-01-01

    View of STS-1 Launch Day Mission Control Center (MCC) activities ending in a scrub on the mission. Photo is of controllers standing in the back of Mission Control with visitor seating in the background.

  9. Effect of Latitude and Seasonal Variation on Scrub Typhus, South Korea, 2001-2013.

    PubMed

    Jeung, Ye Sul; Kim, Choon-Mee; Yun, Na Ra; Kim, Seok-Won; Han, Mi Ah; Kim, Dong-Min

    2016-01-01

    In South Korea, scrub typhus is one of the most common rickettsial diseases. The number of scrub typhus patients has increased in South Korea, a total of 69,210 cases were reported from 2001 to 2013. The seasonality and relation of scrub typhus cases to latitude were analyzed in this article using data obtained from the National Notifiable Diseases Surveillance System website of the Korea Centers for Disease Control and Prevention. The incidence of scrub typhus tended to increase in the later months of the year, especially in October-December. In general, lower latitudes were associated with a later peak incidence. Our results suggest for the first time that the monthly observed incidence tended to increase in the later months of the year as the latitude decreased, and on a yearly basis in Korea.

  10. Thermal decarboxylation of acetic acid: Implications for origin of natural gas

    USGS Publications Warehouse

    Kharaka, Y.K.; Carothers, W.W.; Rosenbauer, R.J.

    1983-01-01

    Laboratory experiments on the thermal decarboxylation of solutions of acetic acid at 200??C and 300??C were carried out in hydrothermal equipment allowing for on-line sampling of both the gas and liquid phases for chemical and stable-carbon-isotope analyses. The solutions had ambient pH values between 2.5 and 7.1; pH values and the concentrations of the various acetate species at the conditions of the experiments were computed using a chemical model. Results show that the concentrations of acetic acid, and not total acetate in solution, control the reaction rates which follow a first order equation based on decreasing concentrations of acetic acid with time. The decarboxylation rates at 200??C (1.81 ?? 10-8 per second) and 300??C (8.17 ?? 10-8 per second) and the extrapolated rates at lower temperatures are relatively high. The activation energy of decarboxylation is only 8.1 kcal/mole. These high decarboxylation rates, together with the distribution of short-chained aliphatic acid anions in formation waters, support the hypothesis that acid anions are precursors for an important portion of natural gas. Results of the ??13C values of CO2, CH4, and total acetate show a reasonably constant fractionation factor of about 20 permil between CO2 and CH4 at 300??C. The ??13C values of CO2 and CH4 are initially low and become higher as decarboxylation increases. ?? 1983.

  11. Characterization of naphthenic acids by gas chromatography-Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Ortiz, Xavier; Jobst, Karl J; Reiner, Eric J; Backus, Sean M; Peru, Kerry M; McMartin, Dena W; O'Sullivan, Gwen; Taguchi, Vince Y; Headley, John V

    2014-08-01

    During the bitumen extraction from the oil sands of Alberta, large volumes of process water containing naphthenic acids are stored in tailing ponds. The naphthenic acids along with other components in the processed waters are known to be toxic in aquatic environments. In view of the complex matrix and the toxicity of the processed waters, there is a need for complementary analytical techniques for comprehensive characterization of the naphthenic acid mixtures. This study reports the online gas chromatographic separation of naphthenic acid mixtures prior to ultrahigh resolution mass spectrometry detection, using electron and chemical ionization. Two oil sands processed water samples and two groundwater samples were characterized to evaluate the performance of the instrumental technique. The high mass resolution of the system enabled visualization of the data using Kendrick mass defect plots. The addition of gas chromatographic separations enabled visualization of the data as unique compound class elution fingerprints. The technique is demonstrated to be a valuable tool for chemical fingerprinting of naphthenic acids. PMID:25001115

  12. Does a robotic scrub nurse improve economy of movements?

    NASA Astrophysics Data System (ADS)

    Wachs, Juan P.; Jacob, Mithun; Li, Yu-Ting; Akingba, George

    2012-02-01

    Objective: Robotic assistance during surgery has been shown to be a useful resource to both augment the surgical skills of the surgeon through tele-operation, and to assist the surgeon handling the surgical instruments to the surgeon, similar to a surgical tech. We evaluated the performance and effect of a gesture driven surgical robotic nurse in the context of economy of movements, during an abdominal incision and closure exercise with a simulator. Methods: A longitudinal midline incision (100 mm) was performed on the simulated abdominal wall to enter the peritoneal cavity without damaging the internal organs. The wound was then closed using a blunt needle ensuring that no tissue is caught up by the suture material. All the instruments required to complete this task were delivered by a robotic surgical manipulator directly to the surgeon. The instruments were requested through voice and gesture recognition. The robotic system used a low end range sensor camera to extract the hand poses and for recognizing the gestures. The instruments were delivered to the vicinity of the patient, at chest height and at a reachable distance to the surgeon. Task performance measures for each of three abdominal incision and closure exercises were measured and compared to a human scrub nurse instrument delivery action. Picking instrument position variance, completion time and trajectory of the hand were recorded for further analysis. Results: The variance of the position of the robotic tip when delivering the surgical instrument is compared to the same position when a human delivers the instrument. The variance was found to be 88.86% smaller compared to the human delivery group. The mean task completion time to complete the surgical exercise was 162.7+/- 10.1 secs for the human assistant and 191.6+/- 3.3 secs (P<.01) when using the robotic standard display group. Conclusion: Multimodal robotic scrub nurse assistant improves the surgical procedure by reducing the number of movements

  13. Meteorological factors and risk of scrub typhus in Guangzhou, southern China, 2006–2012

    PubMed Central

    2014-01-01

    Background Scrub typhus is becoming the most common vector born disease in Guangzhou, southern China. In this study, we aimed to examine the effect of weather patterns on the incidence of Scrub typhus in the subtropical city of Guangzhou for the period 2006–2012, and assist public health prevention and control measures. Methods Scrub typhus reported cases during the period of 2006–2012 in Guangzhou were obtained from National Notifiable Disease Report System (NNDRS). Simultaneous meteorological data including temperature, relative humidity, atmospheric pressure, sunshine, and rainfall were obtained from the documentation of the Guangzhou Meteorological Bureau. A negative binomial regression was used to identify the relationship between meteorological variables and scrub typhus. Results Annual incidence rates of scrub typhus from 2006 to 2012 were 3.25, 2.67, 3.81, 4.22, 4.41, 5.12, and 9.75 (per 100 000) respectively. Each 1°C rise in temperature corresponded to an increase of 14.98% (95% CI 13.65% to 16.33%) in the monthly number of scrub typhus cases, while a 1 hPa rise in atmospheric pressure corresponded to a decrease in the number of cases by 8.03% (95% CI −8.75% to −7.31%). Similarly, a 1 hour rise in sunshine corresponded to an increase of 0.17% or 0.54%, and a 1 millimeter rise in rainfall corresponded to an increase of 0.05% or 0.10%, in the monthly number of scrub typhus cases, depending on the variables considered in the model. Conclusion Our study provided evidence that climatic factors were associated with occurrence of scrub typhus in Guangzhou city, China. Temperature, duration of sunshine, and rainfall were positively associated with scrub typhus incidence, while atmospheric pressure was inversely associated with scrub typhus incidence. These findings should be considered in the prediction of future patterns of scrub typhus transmission. PMID:24620733

  14. A clinical evaluation of chlorhexidine gluconate spray as compared with iodophor scrub for preoperative skin preparation.

    PubMed

    Brown, T R; Ehrlich, C E; Stehman, F B; Golichowski, A M; Madura, J A; Eitzen, H E

    1984-04-01

    In a prospective, randomized study, 737 patients who were evaluated had the operative site prepared preoperatively by either a 0.5 per cent chlorhexidine gluconate spray or povidone-iodine scrub. The wound infection rate in these two comparable groups was not statistically different, although slightly favoring the spray technique (6.0 versus 8.1 per cent). The spray technique challenges the conventional preoperative scrub and offers further advantages of increased effectiveness while also offering savings of time and expense.

  15. Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts

    USGS Publications Warehouse

    Chandler, R.B.; King, D.I.; DeStefano, S.

    2009-01-01

    Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter "beaver") populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition. ?? 2009 by The American Ornithologists' Union. All rights reserved.

  16. Quantification of phenyllactic acid in wheat sourdough using high resolution gas chromatography-mass spectrometry.

    PubMed

    Ryan, Liam Anthony Matthew; Dal Bello, Fabio; Czerny, Michael; Koehler, Peter; Arendt, Elke Karin

    2009-02-11

    In this study, high-resolution gas chromatography-mass spectrometry (HRGC-MS) was successfully used to quantify the level of phenyllactic acid produced by Lactobacillus plantarum strains during sourdough fermentation. Investigation of samples collected during fermentation revealed that the production of phenyllactic acid occurs throughout the growth of L. plantarum in sourdough, but the highest production rate was observed during the logarithmic growth phase. The highest amount, that is, 33.47 mg of phenyllactic acid/kg of dough, was measured in sourdough fermented by the antifungal strain L. plantarum FST 1.7. Sourdoughs fermented by different L. plantarum strains contained different amounts of phenyllactic acid, thus indicating that the production is strain-dependent. Phenylacetic acid was also detected during sourdough analysis, thus showing that the HRGC-MS protocol developed is suitable for the detection not only of phenyllactic acid, but also of a broader range of phenolic acids that are highly relevant, but present in very low amounts in sourdough.

  17. Characterization of 22 Vibrio species by gas chromatography analysis of their cellular fatty acids.

    PubMed

    Urdaci, M C; Marchand, M; Grimont, P A

    1990-05-01

    The cellular fatty acid compositions of 51 Vibrio strains belonging to 22 species as well as five Aeromonas strains were determined by using capillary gas-liquid chromatography (GLC). The major fatty acids were most often hexadecenoic, hexadecanoic and octadecenoic acids. Heptadecenoic acid was present in significant amounts in V. alginolyticus, V. natriegens, V. parahaemolyticus and "Vibrio navarrensis". Twenty fatty acids including branched and hydroxy acids were detected in the genus Vibrio. Quantitative results were treated by principal component analysis to display groups of strains. The first three components (accounting for 69% of the variance) showed the type strains of V. fischeri, V. ordalii, V. damsela, V. mediterranei, V. tubiashii, V. campbellii, V. pelagius, V. gazogenes, and V. nereis to be unclustered. V. alginolyticus (4 strains) and V. parahaemolyticus (4 strains) showed some overlap and the type strain of V. natriegens was in their neighborhood. V. harveyi (4 strains) formed a cluster and V. vulnificus was in its vicinity. V. cholerae (5 strains) overlapped with V. diazotrophicus (3 strains) and was close to the type strain of V. mimicus and V. anguillarum. V. metschnikovii (3 strains) clustered with the type strain of V. cincinnatiensis. A decision tree was devised for the identification of Vibrio species based on qualitative characteristics of fatty acid patterns. However, the following three groups, V. alginolyticus-V. parahaemolyticus-V. natriegens, V. metschnikovii-V. cincinnatiensis and V. cholerae-V. mimicus could not be split into such a decision tree.

  18. Combined liquid and gas chromatographic characterisation of polyglycerol fatty acid esters.

    PubMed

    De Meulenaer, B; Van Royen, G; Vanhoutte, B; Huyghebaert, A

    2000-10-27

    In the present study a combined liquid and gas chromatographic technique is described for the analysis of polyglycerol fatty acid esters. Liquid chromatographic fractionation of samples resulted in pure standards of monoesters of di- and triglycerols and diesters of di- and triglycerols. Confirmation of their identity was achieved by LC-MS analysis. Moreover, a chromatographic identification of the mono- and diesters of cyclic diglycerol was proposed. From the isolation of pure esters and their gas chromatographic analysis, it was revealed that co-elution of several compounds occurred. Thus it was shown that prefractionation of the sample using a simplified liquid chromatographic separation, was necessary in order to characterise the esters correctly. In combination with some other chemical analyses, a complete profile of the chemical composition of polyglycerol fatty acid esters can be obtained.

  19. Electrons Mediate the Gas-Phase Oxidation of Formic Acid with Ozone.

    PubMed

    van der Linde, Christian; Tang, Wai-Kit; Siu, Chi-Kit; Beyer, Martin K

    2016-08-26

    Gas-phase reactions of CO3 (.-) with formic acid are studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Signal loss indicates the release of a free electron, with the formation of neutral reaction products. This is corroborated by adding traces of SF6 to the reaction gas, which scavenges 38 % of the electrons. Quantum chemical calculations of the reaction potential energy surface provide a reaction path for the formation of neutral carbon dioxide and water as the thermochemically favored products. From the literature, it is known that free electrons in the troposphere attach to O2 , which in turn transfer the electron to O3 . O3 (.-) reacts with CO2 to form CO3 (.-) . The reaction reported here formally closes the catalytic cycle for the oxidation of formic acid with ozone, catalyzed by free electrons.

  20. Formation of organic acids from the gas-phase ozonolysis of terpinolene.

    PubMed

    Ma, Yan; Marston, George

    2009-06-01

    Gas-phase ozonolysis of terpinolene was studied in static chamber experiments using gas chromatography coupled to mass spectrometric and flame ionisation detection to separate and detect products. Two isomers of C(7)-diacids and three isomers of C(7)-aldehydic acids were identified in the condensed phase after derivatisation. Possible mechanisms of formation of these acids were investigated using different OH radical scavengers and relative humidities, and were compared to those reported earlier for the ozonolysis of beta-pinene. In addition, branching ratios for some of the individual reaction steps, e.g. the branching ratio between the two hydroperoxide channels of the C(7)-CI, were deduced from the quantitative product yield data. Branching ratios for POZ decomposition and the stabilisation/decomposition of the C(7-)CI were also obtained from measurements of the C(7) primary carbonyl product. PMID:19458821

  1. Elusive Sulfurous Acid: Gas-Phase Basicity and IR Signature of the Protonated Species.

    PubMed

    Sinha, Rajeev K; Scuderi, Debora; Maitre, Philippe; Chiavarino, Barbara; Crestoni, Maria Elisa; Fornarini, Simonetta

    2015-05-01

    The ion corresponding to protonated sulfurous acid, H3SO3(+), has been successfully delivered into the gas phase by electrospray ionization of the solution of a suitable precursor and an in-source fragmentation process. The neutral acid is a highly elusive molecule. However, its gas-phase basicity has been ascertained by means of a kinetic study of proton-transfer reactivity. The structure of the H3SO3(+) sampled ion has been probed by IRMPD spectroscopy in two complementary IR frequency ranges in conjunction with density functional theory calculations and found to conform to a trihydroxosulfonium ion. The characteristic IR signatures may aid in deciphering the presence of this species in extraterrestrial atmospheres. PMID:26263321

  2. Elusive Sulfurous Acid: Gas-Phase Basicity and IR Signature of the Protonated Species.

    PubMed

    Sinha, Rajeev K; Scuderi, Debora; Maitre, Philippe; Chiavarino, Barbara; Crestoni, Maria Elisa; Fornarini, Simonetta

    2015-05-01

    The ion corresponding to protonated sulfurous acid, H3SO3(+), has been successfully delivered into the gas phase by electrospray ionization of the solution of a suitable precursor and an in-source fragmentation process. The neutral acid is a highly elusive molecule. However, its gas-phase basicity has been ascertained by means of a kinetic study of proton-transfer reactivity. The structure of the H3SO3(+) sampled ion has been probed by IRMPD spectroscopy in two complementary IR frequency ranges in conjunction with density functional theory calculations and found to conform to a trihydroxosulfonium ion. The characteristic IR signatures may aid in deciphering the presence of this species in extraterrestrial atmospheres.

  3. Investigation of secondary formation of formic acid: urban environment vs. oil and gas producing region

    NASA Astrophysics Data System (ADS)

    Yuan, B.; Veres, P. R.; Warneke, C.; Roberts, J. M.; Gilman, J. B.; Koss, A.; Edwards, P. M.; Graus, M.; Kuster, W. C.; Li, S.-M.; Wild, R. J.; Brown, S. S.; Dubé, W. P.; Lerner, B. M.; Williams, E. J.; Johnson, J. E.; Quinn, P. K.; Bates, T. S.; Lefer, B.; Hayes, P. L.; Jimenez, J. L.; Weber, R. J.; Zamora, R.; Ervens, B.; Millet, D. B.; Rappenglück, B.; de Gouw, J. A.

    2015-02-01

    Formic acid (HCOOH) is one of the most abundant carboxylic acids in the atmosphere. However, current photochemical models cannot fully explain observed concentrations and in particular secondary formation of formic acid across various environments. In this work, formic acid measurements made at an urban receptor site (Pasadena) in June-July 2010 during CalNex (California Research at the Nexus of Air Quality and Climate Change) and a site in an oil and gas producing region (Uintah Basin) in January-February 2013 during UBWOS 2013 (Uintah Basin Winter Ozone Studies) will be discussed. Although the VOC (volatile organic compounds) compositions differed dramatically at the two sites, measured formic acid concentrations were comparable: 2.3 ± 1.3 in UBWOS 2013 and 2.0 ± 1.0 ppb in CalNex. We determine that concentrations of formic acid at both sites were dominated by secondary formation (> 99%). A constrained box model using the Master Chemical Mechanism (MCM v3.2) underestimates the measured formic acid concentrations drastically at both sites (by a factor of > 10). Compared to the original MCM model that includes only ozonolysis of unsaturated organic compounds and OH oxidation of acetylene, when we updated yields of ozonolysis of alkenes and included OH oxidation of isoprene, vinyl alcohol chemistry, reaction of formaldehyde with HO2, oxidation of aromatics, and reaction of CH3O2 with OH, the model predictions for formic acid were improved by a factor of 6.4 in UBWOS 2013 and 4.5 in CalNex, respectively. A comparison of measured and modeled HCOOH/acetone ratios is used to evaluate the model performance for formic acid. We conclude that the modified chemical mechanism can explain 19 and 45% of secondary formation of formic acid in UBWOS 2013 and CalNex, respectively. The contributions from aqueous reactions in aerosol and heterogeneous reactions on aerosol surface to formic acid are estimated to be 0-6 and 0-5% in UBWOS 2013 and CalNex, respectively. We observe that

  4. Surfactant control of gas transport and reactions at the surface of sulfuric acid.

    PubMed

    Park, Seong-Chan; Burden, Daniel K; Nathanson, Gilbert M

    2009-02-17

    Aerosol particles in the atmosphere are tiny chemical reactors that catalyze numerous reactions, including the conversion of benign gases into ozone-destroying ones. In the lower stratosphere, these particles are often supercooled mixtures of water and sulfuric acid. The different species present at the surface of these droplets (H(2)O, H(3)O(+), HSO(4)(-), H(2)SO(4), and SO(4)(2-)) stand at the "gas-liquid frontier"; as the first to be struck by impinging molecules, these species provide the initial environment for solvation and reaction. Furthermore, aerosol particles may contain a wide range of organic molecules, some of which migrate to the surface and coat the droplet. How do ambient gases dissolve in the droplet if it is coated with an organic layer? At one extreme, monolayer films of insoluble, long-chain alcohols can dramatically reduce gas transport, packing so tightly at the surface of water that they impede water evaporation by factors of 10,000 or more. Shorter chain surfactants are expected to pack less tightly, but we wondered whether these incomplete monolayers also block gas transport and whether this system could serve as a model for understanding the surfaces of atmospheric aerosol particles. To address these questions, our research focuses on small, soluble surfactants such as butanol and hexanol dissolved in supercooled sulfuric acid. These amphiphilic molecules spontaneously segregate to the surface and coat the acid but only to a degree. Gas-liquid scattering experiments reveal that these porous films behave in surprisingly diverse ways: they can impose a barrier (to N(2)O(5) hydrolysis), be "invisible" (to water evaporation), or even enhance gas uptake (of HCl). The transition from obstacle to catalyst can be traced to specific interactions between the surfactant and each gas. For example, the hydrolysis of N(2)O(5) may be impeded because of its large size and because alcohol molecules that straddle the interface limit contact between N(2)O(5

  5. Surfactant control of gas transport and reactions at the surface of sulfuric acid.

    PubMed

    Park, Seong-Chan; Burden, Daniel K; Nathanson, Gilbert M

    2009-02-17

    Aerosol particles in the atmosphere are tiny chemical reactors that catalyze numerous reactions, including the conversion of benign gases into ozone-destroying ones. In the lower stratosphere, these particles are often supercooled mixtures of water and sulfuric acid. The different species present at the surface of these droplets (H(2)O, H(3)O(+), HSO(4)(-), H(2)SO(4), and SO(4)(2-)) stand at the "gas-liquid frontier"; as the first to be struck by impinging molecules, these species provide the initial environment for solvation and reaction. Furthermore, aerosol particles may contain a wide range of organic molecules, some of which migrate to the surface and coat the droplet. How do ambient gases dissolve in the droplet if it is coated with an organic layer? At one extreme, monolayer films of insoluble, long-chain alcohols can dramatically reduce gas transport, packing so tightly at the surface of water that they impede water evaporation by factors of 10,000 or more. Shorter chain surfactants are expected to pack less tightly, but we wondered whether these incomplete monolayers also block gas transport and whether this system could serve as a model for understanding the surfaces of atmospheric aerosol particles. To address these questions, our research focuses on small, soluble surfactants such as butanol and hexanol dissolved in supercooled sulfuric acid. These amphiphilic molecules spontaneously segregate to the surface and coat the acid but only to a degree. Gas-liquid scattering experiments reveal that these porous films behave in surprisingly diverse ways: they can impose a barrier (to N(2)O(5) hydrolysis), be "invisible" (to water evaporation), or even enhance gas uptake (of HCl). The transition from obstacle to catalyst can be traced to specific interactions between the surfactant and each gas. For example, the hydrolysis of N(2)O(5) may be impeded because of its large size and because alcohol molecules that straddle the interface limit contact between N(2)O(5

  6. Prototype demonstration of dual sorbent injection for acid gas control on municipal solid waste combustion units

    SciTech Connect

    1994-05-01

    This report gathered and evaluated emissions and operations data associated with furnace injection of dry hydrated lime and duct injection of dry sodium bicarbonate at a commercial, 1500 ton per day, waste-to-energy facility. The information compiled during the project sheds light on these sorbents to affect acid gas emissions from municipal solid waste combustors. The information assesses the capability of these systems to meet the 1990 Clean Air Act and 1991 EPA Emission Guidelines.

  7. Gas chromatographic/mass spectrometric determination of lysergic acid diethylamide (LSD) in serum samples.

    PubMed

    Musshoff, F; Daldrup, T

    1997-08-01

    A sensitive method for the detection and quantification of lysergic acid diethylamide (LSD) in serum samples is described. After liquid-liquid extraction the trimethylsilyl derivative of LSD is detected by gas chromatography-mass spectrometry. Experiments with spiked samples resulted in a recovery of 76%, the coefficient of variation was 9.3%. Excellent linearity was obtained over the range 0.1-10 ng ml-1. Additionally experiments demonstrating the light sensitivity of LSD are presented together with casuistics.

  8. Effects of emulsified octadecanic acids on gas production and cellulolysis by the rumen anaerobic fungus, Piromyces communis M014.

    PubMed

    Kim, Chang-H; Lee, Shin J; Ha, Jong K; Kim, Wan Y; Lee, Sung S

    2008-02-01

    Responses of the rumen anaerobic fungus, Piromyces communis M014, to octadecanic long-chain fatty acids (LCFAs) were evaluated by measuring total and hydrogen gas productions, filter paper (FP) cellulose degradation and polysaccharidase enzyme activities. Octadecanic acids (stearic acid, C(18:0); oleic acid, C(18:1); linoleic acid, C(18:2) and linolenic acid, C(18:3)) were emulsified by ultrasonication under anaerobic conditions, and added to the medium at the level of 0.001%. When P. communis M014 was grown in culture with stearic and oleic acids, the cumulative gas production, FP cellulose digestion and enzyme activities were significantly (p<0.05) increased in the early incubation times relative to those for the control. However, the addition of linolenic acid inhibited all of the investigated parameters, including cellulose degradation, enzyme activities and gas production, up to 168h incubation. These results indicated that stearic and oleic acids tended to have stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (p<0.05) inhibitory effect on cellulolysis by the rumen fungus. The fungus, P. communis M014, can biohydrogenate C(18) unsaturated fatty acids to escape from their toxic effects. Therefore, in this study, the results indicated that the more highly the added C(18) LCFA to the fungal culture was unsaturated, the higher the inhibition of gas production and cellulase enzyme activity was.

  9. A Hematogenously Disseminated Orientia tsutsugamsushi-Infected Murine Model of Scrub Typhus

    PubMed Central

    Shelite, Thomas R.; Saito, Tais B.; Mendell, Nicole L.; Gong, Bin; Xu, Guang; Soong, Lynn; Valbuena, Gustavo; Bouyer, Donald H.; Walker, David H.

    2014-01-01

    Orientia tsutsugamushi, the etiologic agent of scrub typhus, is a mite-borne rickettsia transmitted by the parasitic larval stage of trombiculid mites. Approximately one-third of the world's population is at risk of infection with Orientia tsutsugamushi, emphasizing its importance in global health. In order to study scrub typhus, Orientia tsutsugamushi Karp strain has been used extensively in mouse studies with various inoculation strategies and little success in inducing disease progression similar to that of human scrub typhus. The objective of this project was to develop a disease model with pathology and target cells similar to those of severe human scrub typhus. This study reports an intravenous infection model of scrub typhus in C57BL/6 mice. This mouse strain was susceptible to intravenous challenge, and lethal infection occurred after intravenous inoculation of 1.25×106 focus (FFU) forming units. Signs of illness in lethally infected mice appeared on day 6 with death occurring ∼6 days later. Immunohistochemical staining for Orientia antigens demonstrated extensive endothelial infection, most notably in the lungs and brain. Histopathological analysis revealed cerebral perivascular, lymphohistiocytic infiltrates, focal hemorrhages, meningoencephalitis, and interstitial pneumonia. Disseminated infection of endothelial cells with Orientia in C57BL/6 mice resulted in pathology resembling that of human scrub typhus. The use of this model will allow detailed characterization of the mechanisms of immunity to and pathogenesis of O. tsutsugamushi infection. PMID:25010338

  10. An investigation of some sterically hindered amines as potential carbon dioxide scrubbing compounds

    SciTech Connect

    Hook, R.J.

    1997-05-01

    In order to improve the efficiency of the carbon dioxide cycling process and to reduce amine emissions, a series of nonvolatile amino acid salts with sterically hindered amine groups were investigated to determine their potential as direct replacements for monoethanolamine (MEA) in submarine-based CO{sub 2} scrubbers. Absorption from atmospheres containing various levels of CO{sub 2} was measured to assess the total capacities and absorption rates of amine solutions. The regeneration rates and extent of CO{sub 2} desorption were established by heating these solutions. {sup 13}C NMR spectroscopy was used to establish reaction products and solution compositions after both absorption and desorption. Methyl groups substituted adjacent to the amine were found to increase solution absorption capacities but with an overall reduction in absorption rate. Poor absorption rates at low CO{sub 2} levels and precipitation problems would prevent the {alpha}-dimethylamines examined from being used in existing submarine scrubbers. These amines, however, show potential as replacements in industrial CO{sub 2} scrubbing processes.

  11. Effect of sublethal gamma radiation on host defenses in experimental scrub typhus

    SciTech Connect

    Kelly, D.J.; Rees, J.C.

    1986-06-01

    The effect of sublethal gamma radiation on inbred mice chronically infected with scrub typhus rickettsiae was examined. Inbred mice which were inoculated with the Gilliam or Karp strain of Rickettsia tsutsugamushi by the subcutaneous route harbored the infection for at least 1 year. Irradiation of these animals at 12 or 52 weeks postinoculation with normally sublethal levels induced a significantly higher percentage of rickettsemic mice (recrudescence) than was seen in the unirradiated, similarly infected control animals. In addition, sublethal irradiation at 12 weeks induced a quantitative increase in total rickettsiae. Homologous antibody titers to the rickettsiae were examined for 5 weeks after irradiation to determine the role of the humoral response in radiation-induced recrudescence. Unirradiated, infected mice showed consistent titers of about 320 throughout the 5-week observation period, and the titer was not affected by exposure of up to 500 rads of gamma radiation. Drug dose-dependent radioprotection and modification of recrudescence was noted in infected, irradiated mice treated with the antiradiation compound S-2-(3-aminopropylamino)ethyl phosphorothioic acid. The results of this investigation supported the conclusion that the recrudescence of a chronic rickettsial infection in the appropriate host after immunological impairment due to gamma radiation can result in an acute, possibly lethal rickettsemia.

  12. Effect on combined cycle efficiency of stack gas temperature constraints to avoid acid corrosion

    NASA Technical Reports Server (NTRS)

    Nainiger, J. J.

    1980-01-01

    To avoid condensation of sulfuric acid in the gas turbine exhaust when burning fuel oils contaning sulfur, the exhaust stack temperature and cold-end heat exchanger surfaces must be kept above the condensation temperature. Raising the exhaust stack temperature, however, results in lower combined cycle efficiency compared to that achievable by a combined cycle burning a sulfur-free fuel. The maximum difference in efficiency between the use of sulfur-free and fuels containing 0.8 percent sulfur is found to be less than one percentage point. The effect of using a ceramic thermal barrier coating (TBC) and a fuel containing sulfur is also evaluated. The combined-cycle efficiency gain using a TBC with a fuel containing sulfur compared to a sulfur-free fuel without TBC is 0.6 to 1.0 percentage points with air-cooled gas turbines and 1.6 to 1.8 percentage points with water-cooled gas turbines.

  13. Determination of phenoxy acid herbicides in water by electron-capture and microcoulometric gas chromatography

    USGS Publications Warehouse

    Goerlitz, D.F.; Lamar, William L.

    1967-01-01

    A sensitive gas chromatographic method using microcoulometric titration and electron-capture detection for the analysis of 2,4-D, silvex, 2,4,5-T, and other phenoxy acid herbicides in water is described. The herbicides are extracted from unfiltered water samples (800-1,000 ml) by use of ethyl ether ; then the herbicides are concentrated and esterilied. To allow the analyst a choice, two esterilication procedures--using either boron trifluoride-methanol or diazomethane--are evaluated. Microcoulometric gas chromatography is specific for the detection of halogenated compounds such as the phenoxy acid herbicides whereas it does not respond to nonhalogenated components. Microcoulometric gas chromatography requires care and patience. It is not convenient for rapid screening of l-liter samples that contain less than 1 microgram of the herbicide. Although electroncapture gas chromatography is less selective and more critically affected by interfering substances, it is, nevertheless, convenient and more sensitive than microcoulometric gas chromatography. Two different liquid phases are used in the gas chromatographic columns--DC-200 silicone in one column and QF-1 silicone in the other. The performance of both columns is improved by the addition of Carbowax 20M. The Gas Chrom Q support is coated with the liquid phases by the 'frontal-analysis' technique. The practical lower limits for measurement of the phenoxy acid herbicides in water primarily depend upon the sample size, interferences present, anal instrumentation used. With l-liter samples of water, the practical lower limits of measurement are 10 ppt (parts per trillion) for 2,4-D and 2 ppt for silvex and 2,4,5-T when electron-capture detection is used, and approximately 20 ppt for each herbicide when analyzed by microcoulometric-titration gas chromatography. Recoveries of the herbicides immediately after addition to unfiltered water samples averaged 92 percent for 2,4-D, 90 percent for silvex, and 98 percent for 2

  14. Prevention of intraoperative wound contamination with chlorhexidine shower and scrub.

    PubMed

    Garibaldi, R A

    1988-04-01

    In a prospective, controlled, clinical trial, we found that preoperative showering and scrubbing with 4% chlorhexidine gluconate was more effective than povidone-iodine or triclocarban medicated soap in reducing skin colonization at the site of surgical incision. Mean log colony counts of the incision site were one half to one log lower for patients who showered with chlorhexidine compared to those who showered with the other regimens. No growth was observed on 43% of the post shower skin cultures from patients in the chlorhexidine group compared with 16% of the cultures from patients who had povidone-iodine showers and 5% of those from patients who used medicated soap and water. The frequency of positive intraoperative wound cultures was 4% with chlorhexidine, 9% with povidone-iodine and 14% with medicated soap and water. This study demonstrates that chlorhexidine gluconate is a more effective skin disinfectant than either povidone-iodine or triclocarban soap and water and that its use is associated with lower rates of intraoperative wound contamination.

  15. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  16. Interaction of Gas Phase Oxalic Acid with Ammonia and its Atmospheric Implications

    SciTech Connect

    Peng, Xiu-Qiu; Liu, Yi-Rong; Huang, Teng; Jiang, Shuai; Huang, Wei

    2015-04-14

    Oxalic acid is believed to play an important role in the formation and growth of atmospheric organic aerosols. However, as a common organic acid, the understanding of the larger clusters formed by gas phase oxalic acid with multiple ammonia molecules is incomplete. In this work, the structural characteristics and thermodynamics of oxalic acid clusters with up to six ammonia molecules have been investigated at the PW91PW91/6-311++G(3df,3pd) level of theory. We found that oxalic acid forms relatively stable clusters with ammonia molecules, and that ionization events play a key role. The analyses of the thermodynamics and atmospheric relevance indicate that the heterodimer (H2C2O4)(NH3) shows an obvious relative concentration in the atmosphere, and thus likely participates in new particle formation. However, with increasing number of ammonia molecules, the concentration of clusters decreases gradually. Additionally, clusters of oxalic acid with ammonia molecules are predicted to form favorably in low temperature conditions and show high Rayleigh scattering intensities.

  17. Investigation of sorbic acid volatile degradation products in pharmaceutical formulations using static headspace gas chromatography.

    PubMed

    Yarramraju, Sitaramaraju; Akurathi, Vamsidhar; Wolfs, Kris; Van Schepdael, Ann; Hoogmartens, Jos; Adams, Erwin

    2007-06-28

    An analytical method that allows simultaneous analysis of sorbic acid and its degradation products was developed using static headspace gas chromatography (HS-GC). AT-Aquawax-DA, the capillary column used, showed good selectivity and separation towards sorbic acid and its degradation products. Sorbic acid degradation was investigated in both acidic and aqueous media at room and elevated temperatures. In total 12 sorbic acid degradation products were found, 8 of which could be characterized. The method was investigated for its accuracy towards estimation of degradation products. Using the HS-GC method different batches of pharmaceutical preparations such as cold cream, cetomacrogol cream and vaseline were investigated for sorbic acid degradation products which were estimated by applying the standard addition method. Acetaldehyde was found to be the major degradation product. The other identified degradation products were: acetone; 2-methylfuran; crotonaldehyde; alfa-angelicalactone; 2-acetyl, 5-methylfuran; toluene and 2,5-dimethylfuran. Both mass spectrometeric (MS) and flame ionization detection (FID) were used. The qualitative investigation was done on HS-GC-MS and the quantitative work on HS-GC-FID. PMID:17306494

  18. Surface Lewis acid-base properties of polymers measured by inverse gas chromatography.

    PubMed

    Shi, Baoli; Zhang, Qianru; Jia, Lina; Liu, Yang; Li, Bin

    2007-05-18

    Surface Lewis acid-base properties are significant for polymers materials. The acid constant, K(a) and base constant, K(b) of many polymers were characterized by some researchers with inverse gas chromatography (IGC) in recent years. In this paper, the surface acid-base constants, K(a) and K(b) of 20 kinds of polymers measured by IGC in recent years are summarized and discussed, including seven polymers characterized in this work. After plotting K(b) versus K(a), it is found that the polymers can be encircled by a triangle. They scatter in two regions of the triangle. Four polymers exist in region I. K(b)/K(a) of the polymers in region I are 1.4-2.1. The other polymers exist in region II. Most of the polymers are relative basic materials.

  19. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Rondo, L.; Ehrhart, S.; Kürten, A.; Adamov, A.; Bianchi, F.; Breitenlechner, M.; Duplissy, J.; Franchin, A.; Dommen, J.; Donahue, N. M.; Dunne, E. M.; Flagan, R. C.; Hakala, J.; Hansel, A.; Keskinen, H.; Kim, J.; Jokinen, T.; Lehtipalo, K.; Leiminger, M.; Praplan, A.; Riccobono, F.; Rissanen, M. P.; Sarnela, N.; Schobesberger, S.; Simon, M.; Sipilä, M.; Smith, J. N.; Tomé, A.; Tröstl, J.; Tsagkogeorgas, G.; Vaattovaara, P.; Winkler, P. M.; Williamson, C.; Wimmer, D.; Baltensperger, U.; Kirkby, J.; Kulmala, M.; Petäjä, T.; Worsnop, D. R.; Curtius, J.

    2016-03-01

    Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4 cluster distribution compared to binary (H2SO4-H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self-contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit.

  20. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    PubMed Central

    Ehrhart, S.; Kürten, A.; Adamov, A.; Bianchi, F.; Breitenlechner, M.; Duplissy, J.; Franchin, A.; Dommen, J.; Donahue, N. M.; Dunne, E. M.; Flagan, R. C.; Hakala, J.; Hansel, A.; Keskinen, H.; Kim, J.; Jokinen, T.; Lehtipalo, K.; Leiminger, M.; Praplan, A.; Riccobono, F.; Rissanen, M. P.; Sarnela, N.; Schobesberger, S.; Simon, M.; Sipilä, M.; Smith, J. N.; Tomé, A.; Tröstl, J.; Tsagkogeorgas, G.; Vaattovaara, P.; Winkler, P. M.; Williamson, C.; Wimmer, D.; Baltensperger, U.; Kirkby, J.; Kulmala, M.; Petäjä, T.; Worsnop, D. R.; Curtius, J.

    2016-01-01

    Abstract Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI‐APi‐TOF (Chemical Ionization‐Atmospheric Pressure interface‐Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI‐APi‐TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4 cluster distribution compared to binary (H2SO4‐H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self‐contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit.

  1. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    PubMed Central

    Ehrhart, S.; Kürten, A.; Adamov, A.; Bianchi, F.; Breitenlechner, M.; Duplissy, J.; Franchin, A.; Dommen, J.; Donahue, N. M.; Dunne, E. M.; Flagan, R. C.; Hakala, J.; Hansel, A.; Keskinen, H.; Kim, J.; Jokinen, T.; Lehtipalo, K.; Leiminger, M.; Praplan, A.; Riccobono, F.; Rissanen, M. P.; Sarnela, N.; Schobesberger, S.; Simon, M.; Sipilä, M.; Smith, J. N.; Tomé, A.; Tröstl, J.; Tsagkogeorgas, G.; Vaattovaara, P.; Winkler, P. M.; Williamson, C.; Wimmer, D.; Baltensperger, U.; Kirkby, J.; Kulmala, M.; Petäjä, T.; Worsnop, D. R.; Curtius, J.

    2016-01-01

    Abstract Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI‐APi‐TOF (Chemical Ionization‐Atmospheric Pressure interface‐Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI‐APi‐TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4 cluster distribution compared to binary (H2SO4‐H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self‐contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit. PMID:27610289

  2. Emission control system for nitrogen oxides using enhanced oxidation, scrubbing, and biofiltration

    SciTech Connect

    Martinez, A.; Cabezas, J.

    2009-05-15

    Nitric oxide (NO) constitutes about 90% of the nitrogen oxide (NOx) species in the flue gases emitted from combustion processes, but NO is difficult to remove in existing scrubbers due to its low solubility. NO may be oxidized with hydrogen peroxide (H{sub 2}O{sub 2}) into soluble species that can be partially removed in wet scrubbers simultaneously with sulfur dioxide (SO{sub 2}) and biofilters located downstream of the scrubber can increase the removal efficiency. This article presents the results of a bench-scale evaluation of such an integrated system combining enhanced oxidation, scrubbing, and biofiltration. Main components of the bench-scale system consisted of a quartz tube in a furnace to simulate the NO oxidation stage and two vertical packed bed cylinders constituting the scrubber and the biofilter. Inlet synthetic gas had a concentration of 50 mu L/L of NO. Overall removal efficiency by the integrated system was in the range of 53% to 93% with an average of 79%, absorption accounted for 43% and biofiltration for 36% of the total removal. Key parameters in the operation of the system are the H{sub 2}O{sub 2}:NO mole ratio, the reaction temperature, the liquid to gas flow ratio, and the biofilter residence time. Experimental results suggest a path for optimization of the technology focusing simultaneously in minimizing H{sub 2}O{sub 2} use in the enhanced oxidation stage, reducing water consumption in the scrubber stage and balancing the residence times in the three stages of the integrated system.

  3. Comparison of the composition and gas/particle partitioning of organic acids in monoterpene and isoprene dominated environments

    NASA Astrophysics Data System (ADS)

    Thompson, S.; Yatavelli, L. R.; Stark, H.; Kimmel, J.; Krechmer, J.; Hu, W.; Palm, B. B.; Campuzano Jost, P.; Day, D. A.; Isaacman, G. A.; Goldstein, A. H.; Khan, M. H.; Holzinger, R.; Lopez-Hilfiker, F.; Mohr, C.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2013-12-01

    Gas and particle-phase organic acids measurements from two different regions with different biogenic volatile organic compound emissions are used to understand gas/particle partitioning principles. A Chemical Ionization High Resolution Time-of-Flight Mass Spectrometer (HRToF-CIMS), with acetate (CH3COO-) as the reagent ion was used to selectively detect acids. Hundreds of gas and particle-phase organic acids were measured in both locations, a monoterpene and MBO-dominated environment (ponderosa pine forest in Colorado, BEACHON-RoMBAS 2011) and isoprene and terpene-dominated environment (mixed deciduous and pine forest in Alabama, SOAS 2013). Time series of gas/particle partitioning for ions consistent with tracers for isoprene oxidation such as methacrylic acid epoxide (MAE) and isoprene epoxydiol (IEPOX) and tracers for α-pinene oxidation such as pinic and pinonic acid will be presented. Gas/particle partitioning, represented as the fraction of each species in the particle-phase, Fp, was calculated for C1-C18 alkanoic acids and biogenic VOC oxidation tracers and compared to an absorptive partitioning model. These results are compared with those of two other instruments that can also quantify gas/particle partitioning with high time resolution: a Semivolatile Thermal Desorption Aerosol GC/MS (SV-TAG) and a Thermal Desorption Proton Transfer Time-of-Flight Mass Spectrometer (TD-PTRMS). Data from both environments were consistent with the values and trends predicted by the absorptive partitioning model for the tracer acids. However, for low carbon number alkanoic acids we report a higher fraction in the particle phase than predicted by the model. The Fp for the bulk-averaged acids and its relationship to the degree of oxidation and carbon number will also be presented. Temporal patterns and correlations with atmospheric conditions and composition will be explored for individual and bulk acids. We will discuss atmospheric implications of the gas/particle partitioning

  4. Simultaneous determination of C2-C22 non-esterified fatty acids and other metabolically relevant carboxylic acids in biological material by gas chromatography of their benzyl esters.

    PubMed

    Schatowitz, B; Gercken, G

    1988-03-18

    A method for the simultaneous determination of non-esterified short-, medium- and long-chain fatty acids and other types of metabolically relevant carboxylic acids such as hydroxy, keto, aromatic and dicarboxylic acids in biological material by capillary gas chromatography of benzyl ester derivatives is described. Sample preparation avoiding incomplete isolation of carboxylic acids consisted of deproteinization and extraction with ethanol, fixation of carboxylic acids as carboxylates, removal of interfering compounds such as neutral lipids by hexane extraction and amino acids, acyl carnitines and other cations by cation-exchange chromatography, derivatization of keto groups of ketocarboxylic acids into O-methyl oximes and benzyl ester formation by reaction of the potassium carboxylates with benzyl bromide via crown ether catalysis. The sample preparation conditions were investigated, showing the usefulness of this method for quantitative determinations. Chromatograms obtained from human serum, human urine and rat heart ventricle and concentrations of carboxylic acids in these specimens are presented. PMID:3372640

  5. Sustainable synthesis of aldehydes, ketones or acids from neat alcohols using nitrogen dioxide gas, and related reactions.

    PubMed

    Naimi-Jamal, M Reza; Hamzeali, Hamideh; Mokhtari, Javad; Boy, Jürgen; Kaupp, Gerd

    2009-01-01

    Benzylic alcohols are quantitatively oxidized by gaseous nitrogen dioxide to give pure aromatic aldehydes. The reaction gas mixtures are transformed to nitric acid, which renders the processes free of waste. The exothermic gas-liquid or gas-solid reactions profit from the solubility of nitrogen dioxide in the neat benzylic alcohols. The acid formed impedes further oxidation of the benzaldehydes. The neat isolated benzaldehydes and nitrogen dioxide quantitatively give the benzoic acids. Solid long-chain primary alcohols are directly and quantitatively oxidized with nitrogen dioxide gas to give the fatty acids in the solid state. The oxidations with ubiquitous nitrogen dioxide are extended to solid heterocyclic thioamides, which gives disulfides, and to diphenylamine, which gives tetraphenylhydrazine. These sustainable (green) specific oxidation procedures produce no dangerous residues from the oxidizing agent or from auxiliaries. PMID:19115303

  6. A Systematic Review of Mortality from Untreated Scrub Typhus (Orientia tsutsugamushi)

    PubMed Central

    Taylor, Andrew J.; Paris, Daniel H.; Newton, Paul N.

    2015-01-01

    Background Scrub typhus, a bacterial infection caused by Orientia tsutsugamushi, is increasingly recognized as an important cause of fever in Asia, with an estimated one million infections occurring each year. Limited access to health care and the disease’s non-specific symptoms mean that many patients are undiagnosed and untreated, but the mortality from untreated scrub typhus is unknown. This review systematically summarizes the literature on the untreated mortality from scrub typhus and disease outcomes. Methodology/Principal Findings A literature search was performed to identify patient series containing untreated patients. Patients were included if they were symptomatic and had a clinical or laboratory diagnosis of scrub typhus and excluded if they were treated with antibiotics. The primary outcome was mortality from untreated scrub typhus and secondary outcomes were total days of fever, clinical symptoms, and laboratory results. A total of 76 studies containing 89 patient series and 19,644 patients were included in the final analysis. The median mortality of all patient series was 6.0% with a wide range (min-max) of 0–70%. Many studies used clinical diagnosis alone and had incomplete data on secondary outcomes. Mortality varied by location and increased with age and in patients with myocarditis, delirium, pneumonitis, or signs of hemorrhage, but not according to sex or the presence of an eschar or meningitis. Duration of fever was shown to be long (median 14.4 days Range (9–19)). Conclusions Results show that the untreated mortality from scrub typhus appears lower than previously reported estimates. More data are required to clarify mortality according to location and host factors, clinical syndromes including myocarditis and central nervous system disease, and in vulnerable mother-child populations. Increased surveillance and improved access to diagnostic tests are required to accurately estimate the untreated mortality of scrub typhus. This

  7. Gas-phase acidities of o-, m- and p-dehydrobenzoic acid radicals. Determination of the substituent constants for a phenyl radical site

    NASA Astrophysics Data System (ADS)

    Wenthold, Paul G.; Squires, Robert R.

    1998-05-01

    Reaction of CO2 with o-, m-, and p-benzyne radical anions in the gas phase produces o-, m-, and p-dehydrobenzoate radical anions, respectively. The (oxygen) gas-phase basicities of these ions, which are equivalent to the gas-phase acidities of the corresponding dehydrobenzoic acid radicals, [Delta]Gacid(o-, m-, or p-C6H4CO2-H), have been determined with a flowing afterglowtriple quadrupole apparatus by means of the kinetic method. The measured values are (in kcal mol-1): [Delta]Gacid(o-C6H4CO2H) = 330.4 +/- 0.4, [Delta]Gacid(m-C6H4CO2H) = 330.2 +/- 0.4, and [Delta]Gacid(p-C6H4CO2H) = 331.6 +/- 0.4 kcal mol-1. All three radicals are more acidic than benzoic acid ([Delta]Gacid = 333.1 +/- 2.0 kcal mol-1). The measured gas-phase acidities for the meta and para isomers suggest values for the resonance-effect substituent constant, [sigma]R, and the field/inductive effect substituent constant, [sigma]F, for a phenyl radical site of - 0.47 and 0.57, respectively. This classifies a phenyl radical site as a strong inductive withdrawing, and strong resonance donating substituent. Density functional calculations of the gas-phase acidities of dehydrobenzoic acids are in good agreement with the experimental results. The increased acidities of the dehydrobenzoic acids are shown to arise from a balance between the electron withdrawing effect of the electronegative radical site, and a compensating polarization of the [pi] system which mimics the effect of a resonance donor group located at the radical carbon.

  8. Synthesis of hierarchical SnO2 nanoflowers with enhanced acetic acid gas sensing properties

    NASA Astrophysics Data System (ADS)

    Jin, W. X.; Ma, S. Y.; Tie, Z. Z.; Li, W. Q.; Luo, J.; Cheng, L.; Xu, X. L.; Wang, T. T.; Jiang, X. H.; Mao, Y. Z.

    2015-10-01

    Different morphologies hierarchical flower-like tin dioxide (SnO2) nanostructures were fabricated by changing the volume ratio of glycol and de-ionized water (Vg:Vw = 0, 1:2, 1:1 and 2:1) under a template-free and low-cost hydrothermal method and subsequent calcinations. The architectures, morphologies and gas sensing performances of the products were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and gas-sensing measurement device. It can be observed that all the nanoflowers were composed of two-dimensional (2D) nanosheets, and the thickness of nanosheets is only about 9 nm when Vg:Vw = 1:1. The sensor based on the product of Vg:Vw = 1:1 exhibited excellent gas sensing performance toward 500 ppm acetic acid at 260 °C, and the response value of this sensor was about 153.6, which was above 7.5 times higher than that of ammonia (about 20.3). In addition, the 3D flower-like SnO2 nanostructures exhibited not only high response and selectivity to ppm level acetone, but also fast response and recovery time within 10 s, demonstrating it can be used as a potential candidate for detecting acetic acid. Finally, the possible formation mechanism was proposed, too.

  9. The singular gas-phase structure of 1-aminocyclopropanecarboxylic acid (Ac3c).

    PubMed

    Jiménez, Ana I; Vaquero, Vanesa; Cabezas, Carlos; López, Juan C; Cativiela, Carlos; Alonso, José L

    2011-07-13

    The natural nonproteinogenic α-amino acid 1-aminocyclopropanecarboxylic acid (Ac(3)c) has been vaporized by laser ablation and studied in the gas phase by molecular-beam Fourier transform microwave spectroscopy. Comparison of the experimental rotational and (14)N nuclear quadrupole coupling constants with the values predicted ab initio for these parameters has allowed the unambiguous identification of three Ac(3)c conformers differing in the hydrogen bonding pattern. Two of them resemble those characterized before for the coded aliphatic α-amino acids. Remarkably, a third conformer predicted to be energetically accessible for all of these amino acids but never observed (the so-called "missing conformer") has been found for Ac(3)c, close in energy to the global minimum. This is the first time that such a conformer, stabilized by an N-H···O(H) hydrogen bond, is detected in the rotational spectrum of a gaseous α-amino acid with a nonpolar side chain. The conjugative interaction established between the cyclopropane ring and the adjacent carbonyl group seems to be responsible for the unique conformational properties exhibited by Ac(3)c.

  10. Assessing the effectiveness of scrub management at the landscape scale using rapid field assessment and remote sensing.

    PubMed

    Redhead, John; Cuevas-Gonzales, Maria; Smith, Geoffrey; Gerard, France; Pywell, Richard

    2012-04-30

    Controlling scrub encroachment is a major challenge for conservation management on chalk grasslands. However, direct comparisons of scrub removal methods have seldom been investigated, particularly at the landscape scale. Effective monitoring of grassland scrub is problematic as it requires simultaneous information on large scale patterns in scrub cover and fine-scale changes in the grassland community. This study addressed this by combining analysis of aerial imagery with rapid field surveys in order to compare the effectiveness of four scrub management strategies on Defence Training Estate Salisbury Plain, UK. Study plots were sited within areas undergoing management and in unmanaged controls. Controls showed dramatic increases in scrub cover, with encroachment of a mean 1096 m(2) per hectare over ten years. Whilst all management strategies were effective in reducing scrub encroachment, they differed in their ability to influence regeneration of scrub and grassland quality. There was a general trend, evident in both the floral community and scrub levels, of increased effectiveness with increasing management intensity. The dual methodology proved highly effective, allowing rapid collection of data over a range of variables and spatial scales unavailable to each method individually. The methodology thus demonstrates potential for a useful monitoring tool.

  11. ELECTRIC POWER GENERATION USING A PHOSPHORIC ACID FUEL CELL ON A MUNICIPAL SOLID WASTE LANDFILL GAS STREAM

    EPA Science Inventory

    The report gives results of tests to verify the performance of a landfill gas pretreatment unit (GPU) and a phorsphoric acid fuel cell system. The complete system removes contaminants from landfill gas and produces electricity for on-site use or connection to an electric grid. Th...

  12. Pyrolytic Methylation-Gas Chromatography of Whole Bacterial Cells for Rapid Profiling of Cellular Fatty Acids

    PubMed Central

    Dworzanski, Jacek P.; Berwald, Luc; Meuzelaar, Henk L. C.

    1990-01-01

    A novel, on-line derivatization technique has been developed which enables generation of fatty acid methyl ester (FAME) profiles from microorganisms by gas chromatography-mass spectrometry without the need for laborious and time-consuming sample preparation. Microgram amounts of bacterial cells are directly applied to a thin ferromagnetic filament and covered with a single drop of methanolic solution of tetramethylammonium hydroxide. After air drying, the filament is inserted into a special gas chromatograph inlet equipped with a high-frequency coil, thus enabling rapid inductive heating of the ferromagnetic filament. This so-called Curie-point heating technique is shown to produce patterns of bacterial FAMEs which are qualitatively and quantitatively nearly identical to those obtained from extracts of methylated lipids prepared by conventional sample pretreatment methods. Relatively minor differences involve the loss of hydroxy-substituted fatty acids by the pyrolytic approach as well as strongly enhanced signals of FAMEs derived from mycolic acids. This type of pyrolysis enables on-line derivatization and thermal extraction of volatile derivatives for analysis, whereas the residual components remain on a disposable probe (ferromagnetic wire) of a pyrolytic device. The reduced sample size (micrograms instead of milligrams) and the lack of sample preparation requirements open up the possibility of rapid microbiological identification of single colonies (thus overcoming the need for time-consuming subculturing) as well as analysis of FAME profiles directly from complex environmental samples. PMID:16348214

  13. What factors within the peri-operative environment influence the training of scrub nurses?

    PubMed

    Pupkiewicz, Joanna; Kitson, Alison; Perry, Josephine

    2015-09-01

    The aim of this study was to extrapolate factors within the peri-operative environment which influence the acclimatisation of novice scrub nurses by exploring the lived experience of learning from both a novice and expert perspective. Insights to the cultural perioperative environment which have not previously been explored can be identified. Comparing how novices view their environment with how expert mentors see it is useful in order to plan targeted learning goals. Two groups were considered; one group consisting of 6 novice scrub nurses and the other consisting of 7 senior scrub nurses teaching novices in a large tertiary teaching public hospital in South Australia. Individual interviews and a focus group interview were digitally recorded and field notes were taken. A Heideggerian structural approach with a vanManen immersive aspect was taken for the data collection and Ricoeur's hermeneutic theory of interpretation was utilised for data analysis. Five emergent themes were isolated from the data: Challenges to proficiency, Fear, Expectations, Support and Adaptation. The study revealed that novice scrub learning is externally modulated by their perioperative cultural surroundings and the support of the senior staff. Senior scrub staff investment in educating novices was dictated by their perception of novice attitude. PMID:25934075

  14. Contrasting genetic structures in sister species of North American scrub-jays

    PubMed Central

    McDonald, D. B.; Potts, W. K.; Fitzpatrick, J. W.; Woolfenden, G. E.

    1999-01-01

    Threatened Florida scrub-jays (Aphelocoma coerulescens breed communally, are restricted to xeric sandy scrub habitat, generally disperse fewer than three territory diameters. Closely related Western scrub-jays (A. californica) do not breed communally, have a broader habitat range, disperse greater distances, and are not threatened. We compared the genetic structure of 445 individuals in 11 populations in Florida with 157 individuals in eight populations of Western scrub-jays. At ten microsatellite loci, Florida had 24 out of 47 total alleles, while Western scrub-jays had 44. The Florida populations were more differentiated (GST = 0.048) than were a set of five California populations (GST = 0.015). A randomization extension of a Mantel test showed a stronger correlation between geographic and Cavalli-Sforza genetic distances among Western than Florida populations. Neighbour-joining trees clustered Florida populations from the same sandy ridge systems, suggesting that habitat continuity is more important than geographic proximity in allowing gene flow and preventing differentiation. For Western populations, isolation by distance appears to be the major determinant of genetic structure. Our results suggest that contrasting genetic structures may arise between closely related species, as a result of differences in ecology and social system. Conserving extant genetic variation in Florida jays will require maintaining viable populations in each of the major sandy ridge systems.

  15. Effect of peat quality on microbial greenhouse gas formation in an acidic fen

    NASA Astrophysics Data System (ADS)

    Reiche, M.; Gleixner, G.; Küsel, K.

    2009-09-01

    Peatlands play an important role in the global carbon cycle and represent both an important stock of soil carbon and a substantial natural source of relevant greenhouse gases like CO2 and CH4. While it is known that the microbial availability of organic matter affects degradation and mineralization processes in peatlands, the manner in which peat organic matter affects the formation of CO2 and CH4 remains unclear. In this study we developed a fast and simple peat quality index in order to estimate its greenhouse gas potential by linking the thermo-degradability of peat with anaerobic CO2 and CH4 formation rates. Peat samples were obtained at several depths (0-40 cm) at four sampling locations from an acidic fen (pH∼4.7). CO2 and CH4 formation rates were highly spatially variable and depended on depth, sampling location, and the composition of pyrolysable organic matter. Peat samples active in CO2 and CH4 formation had a quality index above 1.35, and the fraction of thermally labile pyrolyzable organic matter (comparable to easily available carbon substrates for microbial activity) obtained by thermogravimetry was above 35%. Curie-point pyrolysis-gas chromatography/mass spectrometry mainly identified carbohydrates and lignin as pyrolysis products in these samples, indicating that undecomposed organic matter was found in this fraction. In contrast, lipids and unspecific pyrolysis products, which indicate recalcitrant and highly decomposed organic matter, correlated significantly with lower CO2 formation and reduced methanogenesis. Our results suggest that undecomposed organic matter is a prerequisite for CH4 and CO2 development in acidic fens. Furthermore, the new peat quality index should aide the estimation of greenhouse gas formation potential resulting from peatland restoration and permafrost thawing and help yield more robust models of trace gas fluxes from peatlands for climate change research.

  16. Effect of peat quality on microbial greenhouse gas formation in an acidic fen

    NASA Astrophysics Data System (ADS)

    Reiche, M.; Gleixner, G.; Küsel, K.

    2010-01-01

    Peatlands play an important role in the global carbon cycle and represent both an important stock of soil carbon and a substantial natural source of relevant greenhouse gases like CO2 and CH4. While it is known that the quality of organic matter affects microbial degradation and mineralization processes in peatlands, the manner in which the quality of peat organic matter affects the formation of CO2 and CH4 remains unclear. In this study we developed a fast and simple peat quality index in order to estimate its potential greenhouse gas formation by linking the thermo-degradability of peat with potential anaerobic CO2 and CH4 formation rates. Peat samples were obtained at several depths (0-40 cm) at four sampling locations from an acidic fen (pH 4.7). CO2 and CH4 formation rates were highly spatially variable and depended on depth, sampling location, and the composition of pyrolysable organic matter. Peat samples active in CO2 and CH4 formation had a quality index above 1.35, and the fraction of thermally labile pyrolyzable organic matter (comparable to easily available carbon substrates for microbial activity) obtained by thermogravimetry was above 35%. Curie-point pyrolysis-gas chromatography/mass spectrometry mainly identified carbohydrates and lignin as pyrolysis products in these samples, indicating that undecomposed organic matter was found in this fraction. In contrast, lipids and unspecific pyrolysis products, which indicate recalcitrant and highly decomposed organic matter, correlated significantly with lower CO2 formation and reduced methanogenesis. Our results suggest that undecomposed organic matter is a prerequisite for CH4 and CO2 development in acidic fens. Furthermore, the new peat quality index should aide the estimation of potential greenhouse gas formation resulting from peatland restoration and permafrost thawing and help yield more robust models of trace gas fluxes from peatlands for climate change research.

  17. [Gas chromatography in quantitative analysis of hydrocyanic acid and its salts in cadaveric blood].

    PubMed

    Iablochkin, V D

    2003-01-01

    A direct gas chromatography method was designed for the quantitative determination of cyanides (prussic acid) in cadaveric blood. Its sensitivity is 0.05 mg/ml. The routine volatile products, including substances, which emerge due to putrefaction of organic matters, do not affect the accuracy and reproducibility of the method; the exception is H-propanol that was used as the internal standard. The method was used in legal chemical expertise related with acute cyanide poisoning (suicide) as well as with poisoning of products of combustion of nonmetals (foam-rubber). The absolute error does not exceed 10% with a mean quadratic deviation of 0.0029-0.0033 mg. PMID:14689782

  18. Analysis of the citric acid cycle intermediates using gas chromatography-mass spectrometry.

    PubMed

    Kombu, Rajan S; Brunengraber, Henri; Puchowicz, Michelle A

    2011-01-01

    Researchers view analysis of the citric acid cycle (CAC) intermediates as a metabolomic approach to identifying unexpected correlations between apparently related and unrelated pathways of metabolism. Relationships of the CAC intermediates, as measured by their concentrations and relative ratios, offer useful information to understanding interrelationships between the CAC and metabolic pathways under various physiological and pathological conditions. This chapter presents a relatively simple method that is sensitive for simultaneously measuring concentrations of CAC intermediates (relative and absolute) and other related intermediates of energy metabolism using gas chromatography-mass spectrometry.

  19. [Gas chromatography in quantitative analysis of hydrocyanic acid and its salts in cadaveric blood].

    PubMed

    Iablochkin, V D

    2003-01-01

    A direct gas chromatography method was designed for the quantitative determination of cyanides (prussic acid) in cadaveric blood. Its sensitivity is 0.05 mg/ml. The routine volatile products, including substances, which emerge due to putrefaction of organic matters, do not affect the accuracy and reproducibility of the method; the exception is H-propanol that was used as the internal standard. The method was used in legal chemical expertise related with acute cyanide poisoning (suicide) as well as with poisoning of products of combustion of nonmetals (foam-rubber). The absolute error does not exceed 10% with a mean quadratic deviation of 0.0029-0.0033 mg.

  20. Feasibility study for alternate fuels production: unconventional natural gas from wastewater treatment plants. Volume II, Appendix D. Final report

    SciTech Connect

    Overly, P.; Tawiah, K.

    1981-12-01

    Data are presented from a study performed to determined the feasibility of recovering methane from sewage at a typical biological secondary wastewater treatment plant. Three tasks are involved: optimization of digester gas; digester gas scrubbing; and application to the East Bay Municipal Utility District water pollution control plant. Results indicate that excess digester gas can be used economically at the wastewater treatment plant and that distribution and scrubbing can be complex and costly. (DMC) 193 references, 93 figures, 26 tables.

  1. Determination of linoleic acid in toothpaste by gas chromatography with flame ionization detection.

    PubMed

    Wejnerowska, Grazyna; Gackowska, Alicja; Gaca, Jerzy

    2008-06-01

    A new method for the determination of linoleic acid (LA) in toothpaste by a routine analysis has been proposed. Studies were based on the ISO 5509 procedure, which was modified for the purpose of LA determination in the toothpaste. Gas chromatography (GC) was employed for the qualitative and quantitative determination of linoleic acid methyl ester. The content of LA (5.31%) in sunflower oil added to the toothpaste composition (0.5%) was determined, and then the optimization studies for the determination of LA in the toothpaste samples were carried out. The relative standard deviation (RSD) of the procedure developed was 9.96% (n = 9). The quantitative analysis showed that the content of LA in the toothpaste samples studied was 0.0258 +/- 0.0011%. The detection limit of LA in toothpaste was approximately 0.001%.

  2. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

    NASA Astrophysics Data System (ADS)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  3. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-08-16

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

  4. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

    PubMed Central

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-01-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes. PMID:27526869

  5. Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

    2016-01-01

    Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes. PMID:27526869

  6. Preparation of fatty acid methyl esters for gas-liquid chromatography.

    PubMed

    Ichihara, Ken'ichi; Fukubayashi, Yumeto

    2010-03-01

    A convenient method using commercial aqueous concentrated HCl (conc. HCl; 35%, w/w) as an acid catalyst was developed for preparation of fatty acid methyl esters (FAMEs) from sterol esters, triacylglycerols, phospholipids, and FFAs for gas-liquid chromatography (GC). An 8% (w/v) solution of HCl in methanol/water (85:15, v/v) was prepared by diluting 9.7 ml of conc. HCl with 41.5 ml of methanol. Toluene (0.2 ml), methanol (1.5 ml), and the 8% HCl solution (0.3 ml) were added sequentially to the lipid sample. The final HCl concentration was 1.2% (w/v). This solution (2 ml) was incubated at 45 degrees C overnight or heated at 100 degrees C for 1-1.5 h. The amount of FFA formed in the presence of water derived from conc. HCl was estimated to be <1.4%. The yields of FAMEs were >96% for the above lipid classes and were the same as or better than those obtained by saponification/methylation or by acid-catalyzed methanolysis/methylation using commercial anhydrous HCl/methanol. The method developed here could be successfully applied to fatty acid analysis of various lipid samples, including fish oils, vegetable oils, and blood lipids by GC. PMID:19759389

  7. Preparation of fatty acid methyl esters for gas-liquid chromatography[S

    PubMed Central

    Ichihara, Ken'ichi; Fukubayashi, Yumeto

    2010-01-01

    A convenient method using commercial aqueous concentrated HCl (conc. HCl; 35%, w/w) as an acid catalyst was developed for preparation of fatty acid methyl esters (FAMEs) from sterol esters, triacylglycerols, phospholipids, and FFAs for gas-liquid chromatography (GC). An 8% (w/v) solution of HCl in methanol/water (85:15, v/v) was prepared by diluting 9.7 ml of conc. HCl with 41.5 ml of methanol. Toluene (0.2 ml), methanol (1.5 ml), and the 8% HCl solution (0.3 ml) were added sequentially to the lipid sample. The final HCl concentration was 1.2% (w/v). This solution (2 ml) was incubated at 45°C overnight or heated at 100°C for 1–1.5 h. The amount of FFA formed in the presence of water derived from conc. HCl was estimated to be <1.4%. The yields of FAMEs were >96% for the above lipid classes and were the same as or better than those obtained by saponification/methylation or by acid-catalyzed methanolysis/methylation using commercial anhydrous HCl/methanol. The method developed here could be successfully applied to fatty acid analysis of various lipid samples, including fish oils, vegetable oils, and blood lipids by GC. PMID:19759389

  8. Conformations and spectroscopic properties of laccaic acid A in the gas phase and in implicit water.

    PubMed

    Dokmaisrijan, Supaporn; Payaka, Apirak; Tantishaiyakul, Vimon; Chairat, Montra; Nimmanpipug, Piyarat; Lee, Vannajan Sanghiran

    2013-03-15

    Conformations and spectroscopic properties of laccaic acid A (lacA) were studied by means of the experimental and theoretical approaches. The minimum energy conformers of lacA in the gas phase and in implicit water obtained from the B3LYP/6-311G(d,p) calculations displayed the same orientation of the COOH and OH groups on the anthraquinone-based component. The intramolecular hydrogen bonds (H-bonds) formed between the COOH, C=O and OH groups are very strong. In contrast, the orientations of the Ph(OH)CH(2)CH(2)NHCOCH(3) substituent moiety on the anthraquinone-based component in the gas phase and in implicit water are completely different. The substituent prefers to bind with the anthraquinone-based component in the gas phase while it moves away from the anthraquinone-based component in implicit water. The calculated IR spectra of the two lowest-lying energy conformers of lacA in the gas phase fit to the experimental FTIR spectrum. The full assignments of the vibrational modes with the correlated vibrational wavenumbers of those conformers were proposed here, for the first time. The intramolecular H-bond formations in lacA can cause the shift of the vibrational wavenumber for the COOH, C=O, OH and NH groups as compared to the normal vibrations of these groups. The NMR spectra showed that the stabilities of the two lowest-lying energy conformers of lacA in the gas phase are comparable and this is consistent with their computational energies. The UV-Vis spectra of the lowest-lying energy conformers of lacA in implicit water were compared with the experimental UV-Vis spectrum. The calculations suggested that the electronic transition in the visible region involves with the singlet π→π(*) excitation which the electron density transfers to a COOH group on the anthraquinone ring.

  9. Abducens nerve palsy in a patient with scrub typhus: a case report.

    PubMed

    Bhardwaj, B; Panda, P; Revannasiddaiah, S; Bhardwaj, H

    2013-12-01

    Abducens nerve palsy is a known but rare complication of a few bacterial and viral infections like Mycoplasma pneumonia, cytomegalovirus, Epstein-Barr virus, Hanta virus, herpes zoster, and measles. Abducens nerve palsy due to scrub typhus is extremely rare and so far only one case has been reported in the literature. Scrub typhus is a febrile illness caused by rickettsia, Orientia tsutsugamushi, a gram negative intracellular obligate parasite which is endemic in Asia. This disease can present with wide range of clinical manifestations with involvement of any organ system, alone or in combination. Central nervous system involvement is very common and includes meningism, altered sensorium to focal neurological deficits. We present a rare manifestation of Scrub typhus in the form of sixth cranial nerve involvement which responded to the treatment with doxycycline.

  10. Comparison of the germicidal activity of prepodyne and betadine surgical scrub solutions.

    PubMed

    Kilpatrick, L; Knight, R A

    1975-05-01

    Two iodophoric surgical scrubs soaps, Prepodyne and Betadine, were evaluated for bacteriocidal activity in a modified phenol coefficient test. A standard inoculum of each of 18 species of microorganisms was mixed with a 1:8 dilution of each iodophor and subcultured after one, three, and five minutes of exposure. Complete cidal activty was exhibited by both Prepodyne and Betadine. Twenty-five subjects were tested in hand washing experiments using Betadine and Prepodyne surgical scrub solutions. Quantitative fingerprint cultures were obtained before and after hand washing. Betadine resulted in an 85.2 per cent plus or minus 24 per cent decrease; Prepodyne, and 83.6 per cent plus or minus 21 per cent decrease. It can'be concluded from this data that there is no difference in bacteriocidal effectiveness between the two scrub soaps.

  11. Western scrub-jays do not appear to attend to functionality in Aesop's Fable experiments.

    PubMed

    Logan, Corina J; Harvey, Brigit D; Schlinger, Barney A; Rensel, Michelle

    2016-01-01

    Western scrub-jays are known for their highly discriminatory and flexible behaviors in a caching (food storing) context. However, it is unknown whether their cognitive abilities are restricted to a caching context. To explore this question, we tested scrub-jays in a non-caching context using the Aesop's Fable paradigm, where a partially filled tube of water contains a floating food reward and objects must be inserted to displace the water and bring the food within reach. We tested four birds, but only two learned to drop stones proficiently. Of these, one bird participated in 4/5 experiments and one in 2/5 experiments. Both birds passed one experiment, but without attending to the functional differences of the objects, and failed the other experiments. Scrub-jays were not motivated to participate in these experiments, suggesting that either this paradigm was ecologically irrelevant or perhaps their flexibility is restricted to a caching context.

  12. No evidence of temporal preferences in caching by Western scrub-jays (Aphelocoma californica)☆

    PubMed Central

    Thom, James M.; Clayton, Nicola S.

    2014-01-01

    Humans and other animals often favour immediate gratification over long-term gain. Primates, including humans, appear more willing to wait for rewards than other animals, such as rats or pigeons. Another group displaying impressive patience are the corvids, which possess large brains and show sophisticated cognitive abilities. Here, we assess intertemporal choice in one corvid species, the Western scrub-jay (Aphelocoma californica). These birds cache food for future consumption and respond flexibly to future needs. Cache-theft and cache-degradation are time-dependent processes in scrub-jay ecology that might necessitate sensitivity to delays between caching and retrieval. We adopt a caching paradigm with delays of up to 49 h. Across two experiments we find no evidence of a preference for earlier recovery. We highlight the possibility that, although scrub-jays can discriminate between the present and the future, they may not understand how far into the future an event will occur. PMID:24378212

  13. Stereometabolism of ethylbenzene in man: gas chromatographic determination of urinary excreted mandelic acid enantiomers and phenylglyoxylic acid and their relation to the height of occupational exposure.

    PubMed

    Korn, M; Gfrörer, W; Herz, R; Wodarz, I; Wodarz, R

    1992-01-01

    Ethylbenzene is an important industrial solvent and a key substance in styrene production. Ethylbenzene metabolism leads to the formation of mandelic acid, which occurs in two enantiomeric forms, and phenylglyoxylic acid. To decide which enantiomer is preferably formed, 70 urine samples of exposed workers were taken at the end of shifts and--after 3-pentyl ester derivatisation--gas chromatographically analysed. The R/S ratio of mandelic acid enantiomers in urine amounts to 19:1, which means that R-mandelic acid is a major metabolite and S-mandelic acid is one of the minor urinary metabolites of ethylbenzene in man. The R/S ratio is independent of ambient air concentration of ethylbenzene within the investigated range. Compared to an ethylbenzene monoexposure the height of total mandelic acid excretion is decreased in the case of coexposure to other aromatic solvents.

  14. Benzyl esters of C2-C20 fatty acids and metabolically relevant carboxylic acids. Preparation and gas chromatography-mass spectrometry.

    PubMed

    Schatowitz, B; Gercken, G

    1987-11-13

    Short-, medium- and long-chain fatty acids, and other types of metabolically relevant carboxylic acids like hydroxy-, keto-, aromatic and dicarboxylic acids, were analyzed by capillary gas chromatography. For separation, benzyl ester derivatives were used, prepared by reaction of the potassium carboxylates with benzyl bromide in acetonitrile catalyzed by a crown ether. The reaction conditions for quantitative benzylation were studied. Keto groups of ketocarboxylic acids were stabilized prior to benzylation by formation of O-methyl oximes using methoxyamine hydrochloride in aqueous-ethanolic solution. The separation of more than 45 carboxylic acids was achieved on a CP-Sil 5 CB fused-silica capillary column in less than 70 min. The electron impact mass spectra of ketocarboxylic acid O-methyl oxime benzyl esters PMID:3693495

  15. Gas-Phase Amidation of Carboxylic Acids with Woodward's Reagent K Ions.

    PubMed

    Peng, Zhou; Pilo, Alice L; Luongo, Carl A; McLuckey, Scott A

    2015-10-01

    Gas-phase amidation of carboxylic acids in multiply-charged peptides is demonstrated via ion/ion reactions with Woodward's reagent K (wrk) in both positive and negative mode. Woodward's reagent K, N-ethyl-3-phenylisoxazolium-3'-sulfonate, is a commonly used reagent that activates carboxylates to form amide bonds with amines in solution. Here, we demonstrate that the analogous gas-phase chemistry occurs upon reaction of the wrk ions and doubly protonated (or doubly deprotonated) peptide ions containing the carboxylic acid functionality. The reaction involves the formation of the enol ester intermediate in the electrostatic complex. Upon collisional activation, the ethyl amine on the reagent is transferred to the activated carbonyl carbon on the peptide, resulting in the formation of an ethyl amide (addition of 27 Da to the peptide) with loss of a neutral ketene derivative. Further collision-induced dissociation (CID) of the products and comparison with solution-phase amidation product confirms the structure of the ethyl amide.

  16. Gas-Phase Amidation of Carboxylic Acids with Woodward's Reagent K Ions

    NASA Astrophysics Data System (ADS)

    Peng, Zhou; Pilo, Alice L.; Luongo, Carl A.; McLuckey, Scott A.

    2015-06-01

    Gas-phase amidation of carboxylic acids in multiply-charged peptides is demonstrated via ion/ion reactions with Woodward's reagent K (wrk) in both positive and negative mode. Woodward's reagent K, N-ethyl-3-phenylisoxazolium-3'-sulfonate, is a commonly used reagent that activates carboxylates to form amide bonds with amines in solution. Here, we demonstrate that the analogous gas-phase chemistry occurs upon reaction of the wrk ions and doubly protonated (or doubly deprotonated) peptide ions containing the carboxylic acid functionality. The reaction involves the formation of the enol ester intermediate in the electrostatic complex. Upon collisional activation, the ethyl amine on the reagent is transferred to the activated carbonyl carbon on the peptide, resulting in the formation of an ethyl amide (addition of 27 Da to the peptide) with loss of a neutral ketene derivative. Further collision-induced dissociation (CID) of the products and comparison with solution-phase amidation product confirms the structure of the ethyl amide.

  17. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils.

    PubMed

    Šimek, Miloslav; Virtanen, Seija; Simojoki, Asko; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, Markku

    2014-01-01

    Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg Cg(-1)h(-1), as compared to 2.71 μg Cg(-1)h(-1) in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng Ng(-1)d(-1)). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming.

  18. SAMPLE RESULTS FROM THE NEXT GENERATION SOLVENT PROGRAM REAL WASTE EXTRACTION-SCRUB-STRIP TESTING

    SciTech Connect

    Peters, T.; Washington, A.

    2013-06-03

    Savannah River National Laboratory (SRNL) performed multiple Extraction-Scrub-Strip (ESS) testing using real waste solutions, and three Next Generation Solvent (NGS) variations, which included radiologically clean pure NGS, a blend of radiologically clean NGS and radiologically clean BOBCalixC6 (NGS-MCU), and a blend of radiologically clean NGS and radiologically contaminated BOBCalixC6 from the MCU Solvent system. The results from the tests indicate that both the NGS and the NGS-MCU blend exhibit adequate extraction, scrub and strip behavior.

  19. Sample Results From The Next Generation Solvent Program Real Waste Extraction-Scrub-Strip Testing

    SciTech Connect

    Peters, T. B.; Washington, A. L. II

    2013-08-08

    Savannah River National Laboratory (SRNL) performed multiple Extraction-Scrub-Strip (ESS) testing using real waste solutions, and three Next Generation Solvent (NGS) variations, which included radiologically clean pure NGS, a blend of radiologically clean NGS and radiologically clean BOBCalixC6 (NGS-MCU), and a blend of radiologically clean NGS and radiologically contaminated BOBCalixC6 from the MCU Solvent system. The results from the tests indicate that both the NGS and the NGS-MCU blend exhibit adequate extraction, scrub and strip behavior.

  20. Clear-Cut Stand Size and Scrub-Successional Bird Assemblages

    SciTech Connect

    Krementz,D.G.; Christie, J.S.

    1999-03-08

    We investigated the effects of clear-cut size on species richness, reproductive effort, and relative abundance of scrub-scrub birds at the Savannah River Site. Stands varied in size from 2 to 57 ha that were 2 to 6 years old. Species richness was not explained by stand size or stand age. In regressing stand size on bird species richness, we found a significant negative relationship for the bird community. Frequency of capture was unrelated to stand size. Clear-cut stand size does not appear to be an important variable in forest management with respect to the bird community.

  1. Evaluation of a waterless, scrubless chlorhexidine gluconate/ethanol surgical scrub for antimicrobial efficacy.

    PubMed

    Mulberrry, G; Snyder, A T; Heilman, J; Pyrek, J; Stahl, J

    2001-12-01

    A new waterless surgical hand preparation containing 1% chlorhexidine gluconate (CHG) and 61% ethyl alcohol was evaluated for antimicrobial efficacy in comparison with a standard 4% CHG surgical scrub and a 61% ethyl alcohol control. Clinical studies were based on the Tentative Final Monograph for Health-Care Antiseptic Drug Products (TFM) (proposed rule) and the Standard Test Method for Evaluation of Surgical Hand Scrub Formulations (ASTM E1115-91). Two randomized, blinded, well-controlled clinical studies involving 137 healthy subjects were conducted to evaluate the antimicrobial effectiveness of the CHG/ethanol hand preparation in producing an immediate and persistent reduction in the normal bacterial flora of the hands. The CHG/ethanol hand preparation was applied without scrubbing or the use of water, and a standard 4% CHG reference product was applied with a scrub brush in 2 traditional 3-minute surgical scrubs. In 1 study, a 61% ethanol vehicle control treatment was applied without scrubbing or use of water. During a 5-day period, each study subject performed a series of 11 surgical scrubs with 1 of the test treatments. After the first treatment on days 1, 2, and 5, surgical gloves were worn for 3 or 6 hours. Bacterial samples were taken with the glove-juice technique at 1 minute, 3 hours, and 6 hours after treatment. The immediate bactericidal effect of the CHG/ethanol hand preparation after a single application resulted in a 2.5-log reduction in normal flora. This bactericidal effect persisted throughout the studies and eventually increased to a 3.6-log reduction after the 11th scrub on day 5. The log reductions of the CHG/ethanol hand preparation proved to be significantly better (P <.05) than that of the 4% CHG product at each sampling interval on days 1 and 2 and the sampling at 6 hours on day 5 and significantly better than the 61% ethanol vehicle at all times. The combination of 1% CHG and 61% ethanol had significantly greater microbial reduction than

  2. Replacing personally-identifying information in medical records, the Scrub system.

    PubMed Central

    Sweeney, L.

    1996-01-01

    We define a new approach to locating and replacing personally-identifying information in medical records that extends beyond straight search-and-replace procedures, and we provide techniques for minimizing risk to patient confidentiality. The straightforward approach of global search and replace properly located no more than 30-60% of all personally-identifying information that appeared explicitly in our sample database. On the other hand, our Scrub system found 99-100% of these references. Scrub uses detection algorithms that employ templates and specialized knowledge of what constitutes a name, address, phone number and so forth. PMID:8947683

  3. Absorption of sulfur dioxide from simulated flue gas by polyethyleneimine-phosphoric acid solution.

    PubMed

    Bo, Wen; Li, Hongxia; Zhang, Junjie; Song, Xiangjia; Hu, Jinshan; Liu, Ce

    2016-12-01

    Clean fuel technologies have been widely developed in current society because fuel combustion can directly bring about the emission of hazardous gasses such as SO2. Flue gas desulfurization by polyethyleneimine (PEI)-phosphoric acid solution is an efficient desulfurization method. In this research, the PEI and the additive H3PO4 were used as absorption solution. SO2 was absorbed by the system and desorbed from the loaded solution. The cycle operation was also analyzed. Some technology conditions such as the concentration of PEI, the temperature, the gas flow rate, the concentration of SO2 and the pH value were experimentally researched. With the optimized process, the absorption efficiency of this system could reach 98% and the desorption efficiency was over 60%, showing good absorption/desorption capability. With this efficient approach, the present study may open a new window for developing high-performance absorbents which can make SO2 be well desorbed from the loaded solution and better reused in the flue gas desulfurization. PMID:27082307

  4. Study on removal of elemental mercury from simulated flue gas over activated coke treated by acid

    NASA Astrophysics Data System (ADS)

    Ma, Jinfeng; Li, Caiting; Zhao, Lingkui; Zhang, Jie; Song, Jingke; Zeng, Guangming; Zhang, Xunan; Xie, Yine

    2015-02-01

    This work addressed the investigation of activated coke (AC) treated by acids. Effects of AC samples, modified by ether different acids (H2SO4, HNO3 and HClO4) or HClO4 of varied concentrations, on Hg0 removal were studied under simulated flue gas conditions. In addition, effects of reaction temperature and individual flue gas components including O2, NO, SO2 and H2O were discussed. In the experiments, Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were applied to explore the surface properties of sorbents and possible mechanism of Hg0 oxidation. Results showed that AC sample treated by HClO4 of 4.5 mol/L exhibited maximum promotion of efficiency on Hg0 removal at 160 °C. NO was proved to be positive in the removal of Hg0. And SO2 displayed varied impact in capturing Hg0 due to the integrated reactions between SO2 and modified AC. The addition of O2 could improve the advancement further to some extent. Besides, the Hg0 removal capacity had a slight declination when H2O was added in gas flow. Based on the analysis of XPS and FTIR, the selected sample absorbed Hg0 mostly in chemical way. The reaction mechanism, deduced from results of characterization and performance of AC samples, indicated that Hg0 could firstly be absorbed on sorbent and then react with oxygen-containing (Csbnd O) or chlorine-containing groups (Csbnd Cl) on the surface of sorbent. And the products were mainly in forms of mercuric chloride (HgCl2) and mercuric oxide (HgO).

  5. Human and environmental impact assessment of postcombustion CO2 capture focusing on emissions from amine-based scrubbing solvents to air.

    PubMed

    Veltman, Karin; Singh, Bhawna; Hertwich, Edgar G

    2010-02-15

    Carbon Capture and Storage (CCS) has become a key technology in climate change mitigation programs worldwide. CCS is well-studied in terms of greenhouse gas emission reduction potential and cost of implementation. Impacts on human health and the environment have, however, received considerably less attention. In this work, we present a first assessment of human health and environmental impacts of a postcombustion CO(2) capture facility, focusing on emissions from amine-based scrubbing solvents and their degradation products to air. We develop characterization factors for human toxicity for monoethanolamine (MEA) as these were not yet available. On the basis of the limited information available, our assessment indicates that amine-based scrubbing results in a 10-fold increase in toxic impact on freshwater ecosystems and a minor increase in toxic impacts on terrestrial ecosystems. These increases are attributed to emissions of monoethanolamine. For all other impact categories, i.e., human toxicity, marine ecotoxicity, particulate matter formation, photochemical oxidant formation, and terrestrial acidification, the CO(2) capture facility performs equally well to a conventional NGCC power plant, albeit substantial changes in flue gas composition. The oxidative degradation products of MEA, i.e., formaldehyde, acetaldehyde, and ammonia, do not contribute significantly to total environmental impacts. PMID:20095561

  6. Human and environmental impact assessment of postcombustion CO2 capture focusing on emissions from amine-based scrubbing solvents to air.

    PubMed

    Veltman, Karin; Singh, Bhawna; Hertwich, Edgar G

    2010-02-15

    Carbon Capture and Storage (CCS) has become a key technology in climate change mitigation programs worldwide. CCS is well-studied in terms of greenhouse gas emission reduction potential and cost of implementation. Impacts on human health and the environment have, however, received considerably less attention. In this work, we present a first assessment of human health and environmental impacts of a postcombustion CO(2) capture facility, focusing on emissions from amine-based scrubbing solvents and their degradation products to air. We develop characterization factors for human toxicity for monoethanolamine (MEA) as these were not yet available. On the basis of the limited information available, our assessment indicates that amine-based scrubbing results in a 10-fold increase in toxic impact on freshwater ecosystems and a minor increase in toxic impacts on terrestrial ecosystems. These increases are attributed to emissions of monoethanolamine. For all other impact categories, i.e., human toxicity, marine ecotoxicity, particulate matter formation, photochemical oxidant formation, and terrestrial acidification, the CO(2) capture facility performs equally well to a conventional NGCC power plant, albeit substantial changes in flue gas composition. The oxidative degradation products of MEA, i.e., formaldehyde, acetaldehyde, and ammonia, do not contribute significantly to total environmental impacts.

  7. Dissociation of carbonic acid: gas phase energetics and mechanism from ab initio metadynamics simulations.

    PubMed

    Kumar, P Padma; Kalinichev, Andrey G; Kirkpatrick, R James

    2007-05-28

    A comprehensive metadynamics study of the energetics, stability, conformational changes, and mechanism of dissociation of gas phase carbonic acid, H2CO3, yields significant new insight into these reactions. The equilibrium geometries, vibrational frequencies, and conformer energies calculated using the density functional theory are in good agreement with the previous theoretical predictions. At 315 K, the cis-cis conformer has a very short life time and transforms easily to the cis-trans conformer through a change in the O=C-O-H dihedral angle. The energy difference between the trans-trans and cis-trans conformers is very small (approximately 1 kcal/mol), but the trans-trans conformer is resistant to dissociation to carbon dioxide and water. The cis-trans conformer has a relatively short path for one of its hydroxyl groups to accept the proton from the other end of the molecule, resulting in a lower activation barrier for dissociation. Comparison of the free and potential energies of dissociation shows that the entropic contribution to the dissociation energy is less than 10%. The potential energy barrier for dissociation of H2CO3 to CO2 and H2O from the metadynamics calculations is 5-6 kcal/mol lower than in previous 0 K studies, possibly due to a combination of a finite temperature and more efficient sampling of the energy landscape in the metadynamics calculations. Gas phase carbonic acid dissociation is triggered by the dehydroxylation of one of the hydroxyl groups, which reorients as it approaches the proton on the other end of the molecule, thus facilitating a favorable H-O-H angle for the formation of a product H2O molecule. The major atomic reorganization of the other part of the molecule is a gradual straightening of the O=C=O bond. The metadynamics results provide a basis for future simulation of the more challenging carbonic acid-water system.

  8. Fast derivatization of fatty acids in different meat samples for gas chromatography analysis.

    PubMed

    Figueiredo, Ingrid Lima; Claus, Thiago; Oliveira Santos Júnior, Oscar; Almeida, Vitor Cinque; Magon, Thiago; Visentainer, Jesuí Vergilio

    2016-07-22

    In order to analyze the composition of fatty acids employing gas chromatography as the separation method, a derivatization of lipids using esterification and transesterification reactions is needed. The methodologies currently available are time consuming and use large amounts of sample and reagents. Thus, this work proposes a new procedure to carry out the derivatization of fatty acids without the need for prior extraction of lipids. The use of small amounts of sample (100mg) allows the analysis to be performed in specific parts of animals, in most cases without having them slaughtered. Another benefit is the use of small amounts of reagents (only 2mL of NaOH/Methanol and H2SO4/Methanol). The use of an experimental design procedure (Design Expert software) allows the optimization of the alkaline and acid reaction times. The procedure was validated for five minutes in both steps. The method was validated for bovine fat, beef, chicken, pork, fish and shrimp meats. The results for the merit figures of accuracy (from 101.07% to 109.18%), precision (RSDintra-day (from 0.65 to 3.93%), RSDinter-day (from 1.57 to 5.22%)), linearity (R(2)=0.9864) and robustness confirmed that the new method is satisfactory within the linear range of 2-30% of lipids in the sample. Besides the benefits of minimizing the amount of samples and reagents, the procedure enables gas chromatography sample preparation in a very short time compared with traditional procedures. PMID:27320376

  9. Recent Selected Ion Flow Tube (SIFT) Studies Concerning the Formation of Amino Acids in the Gas Phase

    NASA Technical Reports Server (NTRS)

    Jackson, Douglas M.; Adams, Nigel G.; Babcock, Lucia M.

    2006-01-01

    Recently the simplest amino acid, glycine, has been detected in interstellar clouds, ISC, although this has since been contested. In order to substantiate either of these claims, plausible routes to amino acids need to be investigated. For gas phase synthesis, the SIFT technique has been employed to study simple amino acids via ion-molecule reactions of several ions of interstellar interest with methylamine, ethylamine, formic acid, acetic acid, and methyl formate. Carboxylic acid type ions were considered in the reactions involving the amines. In reactions where the carboxylic acid and methyl formate neutrals were studied, the reactant ions were primarily amine ion fragments. It was observed that the amines and acids preferentially fragment or accept a proton whenever energetically possible. NH3(+), however, uniquely reacted with the neutrals via atom abstraction to form NH4(+). These studies yielded a body of data relevant to astrochemistry, supplementing the available literature. However, the search for gas phase routes to amino acids using conventional molecules has been frustrated. Our most recent research investigates the fragmentation patterns of several amino acids and several possible routes have been suggested for future study.

  10. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    PubMed

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours.

  11. Measurements of gas phase acids in diesel exhaust: a relevant source of HNCO?

    PubMed

    Wentzell, Jeremy J B; Liggio, John; Li, Shao-Meng; Vlasenko, A; Staebler, Ralf; Lu, Gang; Poitras, Marie-Josée; Chan, Tak; Brook, Jeffrey R

    2013-07-16

    Gas-phase acids in light duty diesel (LDD) vehicle exhaust were measured using chemical ionization mass spectrometry (CIMS). Fuel based emission factors (EF) and NOx ratios for these species were determined under differing steady state engine operating conditions. The derived HONO and HNO3 EFs agree well with literature values, with HONO being the single most important acidic emission. Of particular importance is the quantification of the EF for the toxic species, isocyanic acid (HNCO). The emission factors for HNCO ranged from 0.69 to 3.96 mg kgfuel(-1), and were significantly higher than previous biomass burning emission estimates. Further ambient urban measurements of HNCO demonstrated a clear relationship with the known traffic markers of benzene and toluene, demonstrating for the first time that urban commuter traffic is a source of HNCO. Estimates based upon the HNCO-benzene relationship indicate that upward of 23 tonnes of HNCO are released annually from commuter traffic in the Greater Toronto Area, far exceeding the amount possible from LDD alone. Nationally, 250 to 770 tonnes of HNCO may be emitted annually from on-road vehicles, likely representing the dominant source of exposure in urban areas, and with emissions comparable to that of biomass burning. PMID:23781923

  12. The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

    PubMed

    Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

    2012-10-15

    Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours. PMID:22841594

  13. Synthesis of formamide and isocyanic acid after ion irradiation of frozen gas mixtures

    NASA Astrophysics Data System (ADS)

    Kaňuchová, Z.; Urso, R. G.; Baratta, G. A.; Brucato, J. R.; Palumbo, M. E.; Strazzulla, G.

    2016-01-01

    Context. Formamide (NH2HCO) and isocyanic acid (HNCO) have been observed as gaseous species in several astronomical environments such as cometary comae and pre- and proto-stellar objects. A debate is open on the formation route of those molecules, in particular if they are formed by chemical reactions in the gas phase and/or on grains. In this latter case it is relevant to understand if the formation occurs through surface reactions or is induced by energetic processing. Aims: We present arguments that support the formation of formamide in the solid phase by cosmic-ion-induced energetic processing of ices present as mantles of interstellar grains and on comets. Formamides, along with other molecules, are expelled in the gas phase when the physical parameters are appropriate to induce the desorption of ices. Methods: We have performed several laboratory experiments in which ice mixtures (H2O:CH4:N2, H2O:CH4:NH3, and CH3OH:N2) were bombarded with energetic (30-200 keV) ions (H+ or He+). FTIR spectroscopy was performed before, during, and after ion bombardment. In particular, the formation of HNCO and NH2HCO was measured quantiatively. Results: Energetic processing of ice can quantitatively reproduce the amount of NH2HCO observed in cometary comae and in many circumstellar regions. HNCO is also formed, but additional formation mechanisms are requested to quantitatively account for the astronomical observations. Conclusions: We suggest that energetic processing of ices in the pre- and proto-stellar regions and in comets is the main mechanism to produce formamide, which, once it is released in the gas phase because of desorption of ices, is observed in the gas phase in these astrophysical environments.

  14. Use of hexadeuterated valproic acid and gas chromatography-mass spectrometry to determine the pharmacokinetics of valproic acid

    SciTech Connect

    Acheampong, A.A.; Abbott, F.S.; Orr, J.M.; Ferguson, S.M.; Burton, R.W.

    1984-04-01

    Di-(( 3,3,3-/sup 2/H3)propyl)acetic acid, a hexadeuterated analogue of valproic acid, was synthesized and its pharmacokinetic properties compared with valproic acid. Concentrations of valproic acid and (/sup 2/H)valproic acid in serum and saliva were determined by GC-MS using selected-ion monitoring. Saliva drug levels were measured with good precision down to 0.1 microgram/mL. Kinetic equivalence of valproic acid and (/sup 2/H)valproic acid was demonstrated in a single-dose study in a human volunteer. An isotope effect was observed for omega-oxidation, but the difference in metabolism was not sufficient to make (/sup 2/H)valproic acid biologically nonequivalent. The application of (/sup 2/H)valproic acid to determine the kinetics of valproic acid under steady-state concentrations was evaluated in the same volunteer. The kinetic data obtained with (/sup 2/H)valproic acid was consistent with previously reported values for valproic acid including kinetic differences observed between single-dose and steady-state experiments. Saliva levels of valproic acid were found to give a good correlation with total serum valproic acid under multiple-dose conditions. A concentration dependence was found for the ratio of saliva valproic acid to free valproic acid in serum, low ratios being observed at high serum concentrations of valproic acid.

  15. Extraction of DBP and MBP from actinides: application to the recovery of actinides from TBP-sodium carbonate scrub solutions. [Aralex process

    SciTech Connect

    Horwitz, E.P.; Mason, G.W.; Bloomquist, C.A.A.; Leonard, R.A.; Bernstein, G.J.

    1980-01-01

    A flowsheet for the recovery of actinides from TBP-Na/sub 2/CO/sub 3/ scrub waste solutions has been developed, based on batch extraction data, and tested, using laboratory scale counter-current extraction techniques. The process, called the ARALEX process, utilizes 2-ethyl-1-hexanol (2-EHOH) to extract the TBP degradation products (HDBP and H/sub 2/MBP) from acidified Na/sub 2/CO/sub 3/ scrub waste leaving the actinides in the aqueous phase. Dibutyl and monobutyl phosphoric acids are attached to the 2-EHOH molecules through hydrogen bonds. These hydrogen bonds also diminish the ability of the HDBP and H/sub 2/MBP to complex actinides and thus all actinides remain in the aqueous raffinate. Dilute sodium hydroxide solutions can be used to back-extract the dibutyl and monobutyl phosphoric acid esters as their sodium salts. The 2-EHOH can then be recycled. After extraction of the acidified carbonate waste with 2-EHOH, the actinides may be readily extracted from the raffinate with DHDECMP or, in the case of tetra- and hexavalent actinides, with TBP. The ARALEX process is relatively simple and involves inexpensive and readily available chamicals. The ARALEX process can also be applied to other actinide waste streams which contain appreciable concentrations of polar organic compounds that interfere with conventional actinide ion exchange and liquid-liquid extraction procedures. One such application is the removal of detergents from laundry or clean-up solutions contaminated with actinides.

  16. State of the art of diagnosis of rickettsial diseases: the use of blood specimens for diagnosis of scrub typhus, spotted fever group rickettsiosis, and murine typhus

    PubMed Central

    Paris, Daniel H.; Dumler, J. Stephen

    2016-01-01

    Purpose of review With improved malaria control, acute undifferentiated febrile illness studies in tropical regions reveal a startling proportion of rickettsial illnesses, especially scrub typhus, murine typhus, and spotted fever group rickettsioses. Laboratory diagnosis of these infections evolved little over the past 40 years, but combinations of technologies like PCR and loop-mediated isothermal amplification, with refined rapid diagnostic tests and/or ELISA, are promising for guidance for early antirickettsial treatment. Recent findings The long-term reliance on serological tests – useful only late in rickettsial infections – has led to underdiagnosis, inappropriate therapies, and undocumented morbidity and mortality. Recent approaches integrate nucleic acid amplification and recombinant protein-based serological tests for diagnosing scrub typhus. Optimized using Bayesian latent class analyses, this strategy increases diagnostic confidence and enables early accurate diagnosis and treatment – a model to follow for lagging progress in murine typhus and spotted fever. Summary A laboratory diagnostic paradigm shift in rickettsial infections is evolving, with replacement of indirect immunofluorescence assay by the more objective ELISA coupled with nucleic acid amplification assays to expand the diagnostic window toward early infection intervals. This approach supports targeted antirickettsial therapy, reduces morbidity and mortality, and provides a robust evidence base for further development of diagnostics and vaccines. PMID:27429138

  17. Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase.

    PubMed

    Poully, Jean-Christophe; Vizcaino, Violaine; Schwob, Lucas; Delaunay, Rudy; Kocisek, Jaroslav; Eden, Samuel; Chesnel, Jean-Yves; Méry, Alain; Rangama, Jimmy; Adoui, Lamri; Huber, Bernd

    2015-08-01

    Collisions between O(3+) ions and neutral clusters of amino acids (alanine, valine and glycine) as well as lactic acid are performed in the gas phase, in order to investigate the effect of ionizing radiation on these biologically relevant molecular systems. All monomers and dimers are found to be predominantly protonated, and ab initio quantum-chemical calculations on model systems indicate that for amino acids, this is due to proton transfer within the clusters after ionization. For lactic acid, which has a lower proton affinity than amino acids, a significant non-negligible amount of the radical cation monomer is observed. New fragment-ion channels observed from clusters, as opposed to isolated molecules, are assigned to the statistical dissociation of protonated molecules formed upon ionization of the clusters. These new dissociation channels exhibit strong delayed fragmentation on the microsecond time scale, especially after multiple ionization.

  18. Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes.

    PubMed

    Dong, Ki-Young; Choi, Jinnil; Lee, Yang Doo; Kang, Byung Hyun; Yu, Youn-Yeol; Choi, Hyang Hee; Ju, Byeong-Kwon

    2013-01-01

    Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas.

  19. A new Antaeotricha species from Florida sandhills and scrub (Lepidoptera, Depressariidae, Stenomatinae)

    PubMed Central

    Hayden, James E.; Dickel, Terhune S.

    2015-01-01

    Abstract Antaeotricha floridella sp. n. is described and diagnosed from the closely similar Antaeotricha albulella (Walker). The species is distributed in xeric sandhill and scrub habitats in peninsular Florida, USA, and larvae feed on Quercus species. Keys are given for pale-winged Stenomatinae and similar Gelechioidea based on external characters and genitalia. PMID:26668543

  20. Guillan-Barré syndrome following scrub typus: two case reports.

    PubMed

    Sakai, Katsuya; Ishii, Nobuyuki; Ebihara, Yuka; Mochizuki, Hitoshi; Shiomi, Kazutaka; Nakazato, Masamitsu

    2016-08-31

    Case 1: A 66-year-old man was admitted because of progressive gait disturbance and dysphagia after developing red rash. He was diagnosed as Guillain-Barré syndrome (GBS) and treated by intravenous immunoglobulin therapy (IVIg). Two weeks later, he could swallow and walk without any abnormalities. Case 2: A 58-year-old woman was admitted because of gait disturbance, bilateral peripheral facial nerve palsies, and respiratory failure one week after developing fever and rash. She was diagnosed as GBS and treated with IVIg. She underwent mechanical ventilation, while she could wean off it one month later and her limb strengths improved. We confirmed both patients had scrub typhus by serological studies. Peripheral neuropathy is one of the complications of scrub typhus. In addition, this disease sometimes leads to severe GBS. GBS should be included in differential diagnosis when peripheral neuropathies develop in the course of treating scrub typhus, and we should keep in mind that scrub typhus is one of the causes of GBS.

  1. Guillan-Barré syndrome following scrub typus: two case reports.

    PubMed

    Sakai, Katsuya; Ishii, Nobuyuki; Ebihara, Yuka; Mochizuki, Hitoshi; Shiomi, Kazutaka; Nakazato, Masamitsu

    2016-08-31

    Case 1: A 66-year-old man was admitted because of progressive gait disturbance and dysphagia after developing red rash. He was diagnosed as Guillain-Barré syndrome (GBS) and treated by intravenous immunoglobulin therapy (IVIg). Two weeks later, he could swallow and walk without any abnormalities. Case 2: A 58-year-old woman was admitted because of gait disturbance, bilateral peripheral facial nerve palsies, and respiratory failure one week after developing fever and rash. She was diagnosed as GBS and treated with IVIg. She underwent mechanical ventilation, while she could wean off it one month later and her limb strengths improved. We confirmed both patients had scrub typhus by serological studies. Peripheral neuropathy is one of the complications of scrub typhus. In addition, this disease sometimes leads to severe GBS. GBS should be included in differential diagnosis when peripheral neuropathies develop in the course of treating scrub typhus, and we should keep in mind that scrub typhus is one of the causes of GBS. PMID:27477576

  2. Comparison of surgical hand scrub and alcohol surgical hand rub on reducing hand microbial burden.

    PubMed

    Ghorbani, Azam; Shahrokhi, Akram; Soltani, Zahra; Molapour, Azam; Shafikhani, Mahin

    2012-02-01

    This study was performed to compare the effects of two hand decontamination methods on the microbial burden of operating room staff hands. The surgical hand washing methods compared were a traditional surgical hand scrub using a povidone iodine solution, and a social wash using a liquid non-antibacterial soap followed by the application of an alcoholic hand rub. PMID:22724306

  3. AmeriFlux US-KS2 Kennedy Space Center (scrub oak)

    SciTech Connect

    Drake, Bert; Hinkle, Ross

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-KS2 Kennedy Space Center (scrub oak). Site Description - The Kennedy Space Center Scrub Oak site is located within the Merritt Island National Wildlife Refuge at the Kennedy Space Center (KSC) on the east coast of central Florida. Situated in a 10 ha scrub oak ecosystem, the surrounding stand was completely burned by a prescribed fire in 1996. The purpose of the burn was to control understory fuel load, which has been a common practice since 1969. Within a few weeks of the 1996 burn, the stand began to naturally regenerate from roots and rhizomes. Most scrub oak stands in the region undergo a 7 to 10 year disturbance cycle, mostly related to fire or hurricane activity. A severe drought gripped most of Florida beginning in 1998 until the later half of 2001 resulting in four years of relatively low amount of annual rainfall. Exceptionally high annual rainfall amount in 2004 was the result of a pair of hurricanes that hit the area in August and September of 2004. Prevaling wind directions for the site are as follows: W to NW in the winter, afternoon E sea breeze in the summer.

  4. Scrub typhus masquerading as HELLP syndrome and puerperal sepsis in an asymptomatic malaria patient.

    PubMed

    Karim, Habib Md Reazaul; Bhattacharyya, Prithwis; Kakati, Sonai Datta; Borah, Tridip Jyoti; Yunus, Md

    2016-01-01

    Scrub typhus and malaria can involve multiple organ systems and are notoriously known for varied presentations. However, clinical malaria or scrub typhus is unusual without fever. On the other hand, altered sensorium with or without fever, dehydration, hemorrhage and hemolysis may lead to low blood pressure. Presence of toxic granules and elevated band forms in such patients can even mimic sepsis. When such a patient is in the peripartum period, it creates a strong clinical dilemma for the physician especially in unbooked obstetric cases. We present such a case where a 26-year-old unbooked female presented on second postpartum day with severe anemia, altered sensorium, difficulty in breathing along with jaundice and gum bleeding without history of fever. Rapid diagnostic test for malaria was negative and no eschar was seen. These parameters suggested a diagnosis of HELLP (Hemolysis, Elevated Liver enzymes, Low Platelet) syndrome with or without puerperal sepsis. Subsequently she was diagnosed as having asymptomatic malaria and scrub typhus and responded to the treatment of it. The biochemical changes suggestive of HELLP syndrome also subsided. We present this case to emphasize the fact that mere absence of fever and eschar does not rule out scrub typhus. It should also be considered as a differential diagnosis in patients with symptoms and signs suggesting HELLP syndrome. Asymptomatic malaria can complicate case scenario towards puerperal sepsis by giving false toxic granules and band form in such situations. PMID:27413718

  5. Differences in Attentional Strategies by Novice and Experienced Operating Theatre Scrub Nurses

    ERIC Educational Resources Information Center

    Koh, Ranieri Y. I.; Park, Taezoon; Wickens, Christopher D.; Ong, Lay Teng; Chia, Soon Noi

    2011-01-01

    This study investigated the effect of nursing experience on attention allocation and task performance during surgery. The prevention of cases of retained foreign bodies after surgery typically depends on scrub nurses, who are responsible for performing multiple tasks that impose heavy demands on the nurses' cognitive resources. However, the…

  6. The Effects of Elevated CO2 on a Subtropical Scrub Oak-Palmetto Plant Community

    NASA Technical Reports Server (NTRS)

    Vieglais, David; Hinkle, C. Ross; Drake, Bert

    1995-01-01

    A 2.5 year (1992-1995) pilot study was conducted on the effects of twice ambient CO2 on native scrub oak-palmetto vegetation at Kennedy Space Center (KSC). The effects suggest that rising atmospheric CO2 will increase terrestrial carbon and alter the distribution of carbon among the different pools of carbon.

  7. Comparison of minocycline and azithromycin for the treatment of mild scrub typhus in northern China.

    PubMed

    Zhao, Minxing; Wang, Ting; Yuan, Xiaoyu; Du, Weiming; Lin, Miaoxin; Shen, Yanbo

    2016-09-01

    Scrub typhus, caused by Orientia tsutsugamushi, has recently emerged in northern China where the disease had not been known to exist. Although doxycycline and azithromycin are the recommended agents for the treatment of scrub typhus, clinical responses depend both on the susceptibilities of various O. tsutsugamushi strains and the severity of the disease. A retrospective analysis was conducted on patients diagnosed with mild scrub typhus from August 2013 to January 2016 in the Affiliated Hospital of Nantong University, northern China. A total of 40 patients who received minocycline treatment and 34 patients who received azithromycin treatment were included in the analysis. All patients except one defervesced within 120 h after initiating antimicrobial therapy. Kaplan-Meier curves in association with log-rank test showed that the median time to defervescence was significantly shorter for the minocycline-treated group than the azithromycin-treated group (P = 0.003). There were no serious adverse events during treatment. No relapse occurred in either group during the 1-month follow-up period. In conclusion, both minocycline and azithromycin are effective and safe for the treatment of mild scrub typhus, but minocycline is more active than azithromycin against O. tsutsugamushi infection acquired in northern China. PMID:27449540

  8. Formation of Amino Acids on the Sonolysis of Aqueous Solutions Containing Acetic Acid, Methane, or Carbon Dioxide, in the Presence of Nitrogen Gas.

    PubMed

    Dharmarathne, Leena; Grieser, Franz

    2016-01-21

    The sonolysis of aqueous solutions containing acetic acid, methane, or carbon dioxide in the presence of nitrogen gas was found to produce a number of different amino acids at a rate of ∼1 to 100 nM/min, using ultrasound at an operating power of 70 W and 355 kHz. Gas-phase elementary reactions are suggested, and discussed, to account for the formation of the complex biomolecules from the low molar mass solutes used. On the basis of the results, a new hypothesis is presented to explain the formation of amino acids under primitive atmospheric conditions and how their formation may be linked to the eventual abiotic genesis of life on Earth.

  9. Formation of Amino Acids on the Sonolysis of Aqueous Solutions Containing Acetic Acid, Methane, or Carbon Dioxide, in the Presence of Nitrogen Gas.

    PubMed

    Dharmarathne, Leena; Grieser, Franz

    2016-01-21

    The sonolysis of aqueous solutions containing acetic acid, methane, or carbon dioxide in the presence of nitrogen gas was found to produce a number of different amino acids at a rate of ∼1 to 100 nM/min, using ultrasound at an operating power of 70 W and 355 kHz. Gas-phase elementary reactions are suggested, and discussed, to account for the formation of the complex biomolecules from the low molar mass solutes used. On the basis of the results, a new hypothesis is presented to explain the formation of amino acids under primitive atmospheric conditions and how their formation may be linked to the eventual abiotic genesis of life on Earth. PMID:26695890

  10. Dissolver Off-gas Hot Operations Authorization (AFCI CETE Milestone Report)

    SciTech Connect

    Jubin, Robert Thomas

    2009-06-01

    The head-end processing of the Coupled-End-to-End (CETE) Demonstration includes fuel receipt, fuel disassembly, exposure of fuel (e.g., by segmenting the fuel pins), voloxidation of the fuel to separate tritium, and fuel dissolution. All of these processing steps with the exception of the dissolution step will be accomplished in the Irradiated Fuels Examination Laboratory (IFEL) (Building 3525). The final headend step will be performed in the Radiochemical Engineering Development Center (Building 7920). The primary purpose of the fuel dissolution step is to prepare the solid fuel for subsequent liquid separations steps. This is accomplished by dissolving the fuel solids using nitric acid. During the dissolution process gases are evolved. Oxides of nitrogen are the primary off-gas components generated by the reactions of nitric acid and the fuel oxides however, during the dissolution and sparging of the resulting solution, iodine, C-14 as carbon dioxide, xenon, and krypton gasses are also released to the off-gas stream. The Dissolver Off-gas treatment rack provides a means of trapping these volatile fission products and other gases via various trapping media. Specifically the rack will recover iodine on a solid sorbent bed, scrub NOx in a water/acid column, scrub CO{sub 2} in a caustic scrubber column, remove moisture with solid sorbent drier beds and recover Xe and Kr using solid absorbent beds. The primary purpose of this experimental rack and the off-gas rack associated with the voloxidation equipment located at IFEL is to close the material balances around the volatile gases and to provide an understanding of the impacts of specific processing conditions on the fractions of the volatile components released from the various head-end processing steps.

  11. Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures

    SciTech Connect

    Wiberg, Gustav K. H. E-mail: m.arenz@chem.ku.dk; Fleige, Michael; Arenz, Matthias E-mail: m.arenz@chem.ku.dk

    2015-02-15

    We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow field are braced using a KF-25 vacuum flange clamp, which allows an easy assembly of the setup. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on high surface area type electrocatalysts, but it also enables quick screening tests of HT-PEMFC catalysts under realistic conditions.

  12. Advanced Acid Gas Separation Technology for Clean Power and Syngas Applications

    SciTech Connect

    Amy, Fabrice; Hufton, Jeffrey; Bhadra, Shubhra; Weist, Edward; Lau, Garret; Jonas, Gordon

    2015-06-30

    Air Products has developed an acid gas removal technology based on adsorption (Sour PSA) that favorably compares with incumbent AGR technologies. During this DOE-sponsored study, Air Products has been able to increase the Sour PSA technology readiness level by successfully operating a two-bed test system on coal-derived sour syngas at the NCCC, validating the lifetime and performance of the adsorbent material. Both proprietary simulation and data obtained during the testing at NCCC were used to further refine the estimate of the performance of the Sour PSA technology when expanded to a commercial scale. In-house experiments on sweet syngas combined with simulation work allowed Air Products to develop new PSA cycles that allowed for further reduction in capital expenditure. Finally our techno economic analysis of the use the Sour PSA technology for both IGCC and coal-to-methanol applications suggests significant improvement of the unit cost of electricity and methanol compared to incumbent AGR technologies.

  13. Incorporation of small BN domains in graphene during CVD using methane, boric acid and nitrogen gas.

    PubMed

    Bepete, George; Voiry, Damien; Chhowalla, Manish; Chiguvare, Zivayi; Coville, Neil J

    2013-07-21

    Chemical doping of graphene with small boron nitride (BN) domains has been shown to be an effective way of permanently modulating the electronic properties in graphene. Herein we show a facile method of growing large area graphene doped with small BN domains on copper foils using a single step CVD route with methane, boric acid powder and nitrogen gas as the carbon, boron and nitrogen sources respectively. This facile and safe process avoids the use of boranes and ammonia. Optical microscopy confirmed that continuous films were grown and Raman spectroscopy confirmed changes in the electronic structure of the grown BN doped graphene. Using XPS studies we find that both B and N can be substituted into the graphene structure in the form of small BN domains to give a B-N-C system. A novel structure for the BN doped graphene is proposed. PMID:23759928

  14. Alterations in acid-base status and blood gas dynamics during progressive hyperkalaemia in neonatal calves.

    PubMed

    Singh, A; Randhawa, S S; Setia, M S

    1989-03-01

    Alterations in acid-base status and blood-gas dynamics were studied during induced progressive hyperkalaemia in neonatal calves. The hyperkalaemia was associated initially with respiratory alkalosis in arterial blood when plasma K+ was increased to 6.08 +/- 1.02 mmol litre-1. The rise of plasma K+ above 6.08 +/- 1.02 mmol litre-1 led to the development of metabolic acidosis in arterial and venous blood. There was partial respiratory compensation. Plasma K+ concentrations at or above 11.03 +/- 0.34 mmol litre-1 were associated with a decrease in arterial oxygen tension and arterial oxygen saturation. The oxygen extraction ratio was increased during hyperkalaemia.

  15. Incorporation of small BN domains in graphene during CVD using methane, boric acid and nitrogen gas.

    PubMed

    Bepete, George; Voiry, Damien; Chhowalla, Manish; Chiguvare, Zivayi; Coville, Neil J

    2013-07-21

    Chemical doping of graphene with small boron nitride (BN) domains has been shown to be an effective way of permanently modulating the electronic properties in graphene. Herein we show a facile method of growing large area graphene doped with small BN domains on copper foils using a single step CVD route with methane, boric acid powder and nitrogen gas as the carbon, boron and nitrogen sources respectively. This facile and safe process avoids the use of boranes and ammonia. Optical microscopy confirmed that continuous films were grown and Raman spectroscopy confirmed changes in the electronic structure of the grown BN doped graphene. Using XPS studies we find that both B and N can be substituted into the graphene structure in the form of small BN domains to give a B-N-C system. A novel structure for the BN doped graphene is proposed.

  16. Incorporation of small BN domains in graphene during CVD using methane, boric acid and nitrogen gas

    NASA Astrophysics Data System (ADS)

    Bepete, George; Voiry, Damien; Chhowalla, Manish; Chiguvare, Zivayi; Coville, Neil J.

    2013-06-01

    Chemical doping of graphene with small boron nitride (BN) domains has been shown to be an effective way of permanently modulating the electronic properties in graphene. Herein we show a facile method of growing large area graphene doped with small BN domains on copper foils using a single step CVD route with methane, boric acid powder and nitrogen gas as the carbon, boron and nitrogen sources respectively. This facile and safe process avoids the use of boranes and ammonia. Optical microscopy confirmed that continuous films were grown and Raman spectroscopy confirmed changes in the electronic structure of the grown BN doped graphene. Using XPS studies we find that both B and N can be substituted into the graphene structure in the form of small BN domains to give a B-N-C system. A novel structure for the BN doped graphene is proposed.

  17. Infrared and density functional theory studies of formic acid hydrate clusters in noble gas matrices

    NASA Astrophysics Data System (ADS)

    Ito, Fumiyuki

    2016-08-01

    Infrared absorption spectra of formic acid hydrate clusters (HCOOH)m(H2O)n have been measured in noble gas matrices (Ar and Kr). The concentration dependence of the spectra and the comparison with a previous experimental study on HCOOH(H2O) and HCOOH(H2O)2 [Geoge et al., Spectrochim. Acta, Part A 60 (2004) 3225] led to the identification of large clusters. Density functional theory calculations at the B3LYP-DCP/6-31+G(2d,2p) level were carried out to determine the anharmonic vibrational properties of the clusters, enabling a consistent assignment of the observed vibrational peaks to specific clusters.

  18. Acid gas treating by aqueous alkanolamines. Annual report, January-December 1994

    SciTech Connect

    Sandall, O.C.; Rinker, E.B.; Ashour, S.

    1994-12-01

    The objective of this work is to investigate the simulateneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed this year the authors have measured the density, viscosity and surface tension of pure MDEA and DEA over a range in temperatures. The diffusivity of N2O was measured in aqueous blends of MDEA and DEA at 50 wt% total amine for various ratios of DEA to MDEA over the temperature range 20 to 80 deg. C. A theoretically-based model has been developed for the correlation of the physical solubility of N2O in aqueous amine solutions. A penetration theory type model which was developed to describe acid gas absorption in aqueous amine solutions was used to carry out a sensitivity analysis for the various parameters affecting the rate of absorption of CO2 in MDEA solutions.

  19. 2005 Crater Lake Formation, Lahar, Acidic Flood, and Gas Emission From Chiginagak Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Schaefer, J. R.; Scott, W. E.; McGimsey, R. G.; Jorgenson, J.

    2005-12-01

    A 400-m-wide crater lake developed in the formerly snow-and-ice-filled crater of Mount Chiginagak volcano sometime between August 2004 and June 2005, presumably due to increased heat flux from the hydrothermal system. We are also evaluating the possible role of magma intrusion and degassing. In early summer 2005, clay-rich debris and an estimated 5.6 million cubic meters of acidic water from the crater exited through tunnels in the base of a glacier that breaches the south crater rim. Over 27 kilometers downstream, the acidic waters of the flood reached approximately 1.5 meters above current water levels and inundated an important salmon spawning drainage, acidifying at least the surface water of Mother Goose Lake (approximately 1 cubic kilometer in volume) and preventing the annual salmon run. No measurements of pH were taken until late August 2005. At that time the pH of water sampled from the Mother Goose Lake inlet, lake surface, and outlet stream (King Salmon River) was 3.2. Defoliation and leaf damage of vegetation along affected streams, in areas to heights of over 70 meters in elevation above flood level, indicates that a cloud of detrimental gas or aerosol accompanied the flood waters. Analysis of stream water, lake water, and vegetation samples is underway to better determine the agent responsible for the plant damage. This intriguing pattern of gas-damaged vegetation concentrated along and above the flood channels is cause for further investigation into potential hazards associated with Chiginagak's active crater lake. Anecdotal evidence from local lodge owners and aerial photographs from 1953 suggest that similar releases occurred in the mid-1970s and early 1950s.

  20. Effects of nitric acid gas alone or in combination with ozone on healthy volunteers

    SciTech Connect

    Aris, R.; Christian, D.; Tager, I.; Ngo, L.; Finkbeiner, W.E.; Balmes, J.R. )

    1993-10-01

    Nitric acid (HNO3) is the most prevalent acid air pollutant in the western United States and has the potential to cause adverse respiratory effects through both acidification and oxidation reactions. To study this potential, we measured physiologic (specific airway resistance, SRaw, FEV1, and FVC) and bronchoalveolar lavage (total and differential cell counts, LDH, fibronectin, and total protein) end points in a group of 10 healthy, athletic subjects who were exposed to 500 micrograms/m3 of HNO3 gas or filtered air for 4 h during moderate exercise (ventilatory rate, 40 L/min) and underwent bronchoscopy 18 h later. Under an identical protocol, 10 healthy subjects were exposed to 500 micrograms/m3 of HNO3 gas plus 0.20 ppm ozone (O3) or 0.20 ppm O3 alone to determine if HNO3 might enhance the toxicity of O3. In addition to bronchoalveolar lavage (BAL), we employed the techniques of isolated left mainstem bronchial lavage and bronchial biopsy to determine if proximal airway injury was caused by pollutant exposure and whether there was any correlation with the degree of distal lung injury as assessed by BAL. We found no significant differences in pulmonary function tests or in the cellular or biochemical constituents in either the BAL or the left mainstem lavage fluids between the HNO3 and the air exposures. Similarly, there were no differences in these end points between the HNO3/O3 and the O3 exposures. Furthermore, there were no significant differences in the bronchial biopsy specimens between the HNO3 and air exposures or between the HNO3/O3 and O3 exposures.

  1. Fatty acid composition of wild mushroom species of order Agaricales--examination by gas chromatography-mass spectrometry and chemometrics.

    PubMed

    Marekov, Ilko; Momchilova, Svetlana; Grung, Bjørn; Nikolova-Damyanova, Boryana

    2012-12-01

    Applying gas chromatography-mass spectrometry of 4,4-dimethyloxazoline fatty acid derivatives, the fatty acid composition of 15 mushroom species belonging to 9 genera and 5 families of order Agaricales growing in Bulgaria is determined. The structure of 31 fatty acids (not all present in each species) is unambiguously elucidated, with linoleic, oleic and palmitic acids being the main components (ranging between 70.9% (Marasmius oreades) and 91.2% (Endoptychum agaricoides)). A group of three hexadecenoic positionally isomeric fatty acids, 6-, 9- and 11-16:1, appeared to be characteristic components of the examined species. By applying chemometrics it was possible to show that the fatty acid composition closely reflects the classification of the species.

  2. Multistate modeling of habitat dynamics: Factors affecting Florida scrub transition probabilities

    USGS Publications Warehouse

    Breininger, D.R.; Nichols, J.D.; Duncan, B.W.; Stolen, Eric D.; Carter, G.M.; Hunt, D.K.; Drese, J.H.

    2010-01-01

    Many ecosystems are influenced by disturbances that create specific successional states and habitat structures that species need to persist. Estimating transition probabilities between habitat states and modeling the factors that influence such transitions have many applications for investigating and managing disturbance-prone ecosystems. We identify the correspondence between multistate capture-recapture models and Markov models of habitat dynamics. We exploit this correspondence by fitting and comparing competing models of different ecological covariates affecting habitat transition probabilities in Florida scrub and flatwoods, a habitat important to many unique plants and animals. We subdivided a large scrub and flatwoods ecosystem along central Florida's Atlantic coast into 10-ha grid cells, which approximated average territory size of the threatened Florida Scrub-Jay (Aphelocoma coerulescens), a management indicator species. We used 1.0-m resolution aerial imagery for 1994, 1999, and 2004 to classify grid cells into four habitat quality states that were directly related to Florida Scrub-Jay source-sink dynamics and management decision making. Results showed that static site features related to fire propagation (vegetation type, edges) and temporally varying disturbances (fires, mechanical cutting) best explained transition probabilities. Results indicated that much of the scrub and flatwoods ecosystem was resistant to moving from a degraded state to a desired state without mechanical cutting, an expensive restoration tool. We used habitat models parameterized with the estimated transition probabilities to investigate the consequences of alternative management scenarios on future habitat dynamics. We recommend this multistate modeling approach as being broadly applicable for studying ecosystem, land cover, or habitat dynamics. The approach provides maximum-likelihood estimates of transition parameters, including precision measures, and can be used to assess

  3. Clinical Evaluation of Rapid Diagnostic Test Kit for Scrub Typhus with Improved Performance

    PubMed Central

    2016-01-01

    Diagnosis of scrub typhus is challenging due to its more than twenty serotypes and the similar clinical symptoms with other acute febrile illnesses including leptospirosis, murine typhus and hemorrhagic fever with renal syndrome. Accuracy and rapidity of a diagnostic test to Orientia tsutsugamushi is an important step to diagnose this disease. To discriminate scrub typhus from other diseases, the improved ImmuneMed Scrub Typhus Rapid Diagnostic Test (RDT) was evaluated in Korea and Sri Lanka. The sensitivity at the base of each IgM and IgG indirect immunofluorescent assay (IFA) in Korean patients was 98.6% and 97.1%, and the specificity was 98.2% and 97.7% respectively. The sensitivity and specificity for retrospective diagnosis at the base of IFA in Sri Lanka was 92.1% and 96.1%. ImmuneMed RDT was not reactive to any serum from seventeen diseases including hemorrhagic fever with renal syndrome (n = 48), leptospirosis (n = 23), and murine typhus (n = 48). ImmuneMed RDT shows superior sensitivity (98.6% and 97.1%) compared with SD Bioline RDT (84.4% at IgM and 83.3% at IgG) in Korea. The retrospective diagnosis of ImmuneMed RDT exhibits 94.0% identity with enzyme-linked Immunosorbent assay (ELISA) using South India patient serum samples. These results suggest that this RDT can replace other diagnostic tests and is applicable for global diagnosis of scrub typhus. This rapid and accurate diagnosis will be beneficial for diagnosing and managing scrub typhus. PMID:27478327

  4. Clinical Evaluation of Rapid Diagnostic Test Kit for Scrub Typhus with Improved Performance.

    PubMed

    Kim, Young-Jin; Park, Sungman; Premaratna, Ranjan; Selvaraj, Stephen; Park, Sang-Jin; Kim, Sora; Kim, Donghwan; Kim, Min Soo; Shin, Dong Hoon; Choi, Kyung-Chan; Kwon, Soon-Hwan; Seo, Wonjun; Lee, Nam Taek; Kim, Seung-Han; Kang, Heui Keun; Kim, Yoon-Won

    2016-08-01

    Diagnosis of scrub typhus is challenging due to its more than twenty serotypes and the similar clinical symptoms with other acute febrile illnesses including leptospirosis, murine typhus and hemorrhagic fever with renal syndrome. Accuracy and rapidity of a diagnostic test to Orientia tsutsugamushi is an important step to diagnose this disease. To discriminate scrub typhus from other diseases, the improved ImmuneMed Scrub Typhus Rapid Diagnostic Test (RDT) was evaluated in Korea and Sri Lanka. The sensitivity at the base of each IgM and IgG indirect immunofluorescent assay (IFA) in Korean patients was 98.6% and 97.1%, and the specificity was 98.2% and 97.7% respectively. The sensitivity and specificity for retrospective diagnosis at the base of IFA in Sri Lanka was 92.1% and 96.1%. ImmuneMed RDT was not reactive to any serum from seventeen diseases including hemorrhagic fever with renal syndrome (n = 48), leptospirosis (n = 23), and murine typhus (n = 48). ImmuneMed RDT shows superior sensitivity (98.6% and 97.1%) compared with SD Bioline RDT (84.4% at IgM and 83.3% at IgG) in Korea. The retrospective diagnosis of ImmuneMed RDT exhibits 94.0% identity with enzyme-linked Immunosorbent assay (ELISA) using South India patient serum samples. These results suggest that this RDT can replace other diagnostic tests and is applicable for global diagnosis of scrub typhus. This rapid and accurate diagnosis will be beneficial for diagnosing and managing scrub typhus. PMID:27478327

  5. Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy

    SciTech Connect

    Bullin, J.A.; Frazier, R.E.

    1991-09-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor -- liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor -- liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

  6. Gas/particle partitioning behavior of perfluorocarboxylic acids with terrestrial aerosols.

    PubMed

    Arp, Hans Peter H; Goss, Kai-Uwe

    2009-11-15

    Experimentally determined gas/particle partitioning constants, K(ip), using inverse gas chromatography (IGC) are presented for perfluorocarboxylic acids (PFCAs), covering a diverse set of terrestrial aerosols over an ambient range of relative humidity (RH) and temperature. The results are compared to estimated K(ip) values using a recently developed model that has been validated for diverse neutral and ionizable organic compounds. The modeling results consistently underestimate the experimental results. This is likely due to additional partition mechanisms unique for surfactants not being accounted for in the model, namely aggregate formation and water surface adsorption. These processes likely also biased the IGC K(ip) measurements compared to ambient PFCA concentrations. Nevertheless, both the experimental and modeling results indicate that partitioning to terrestrial particles in ambient atmospheres is negligible, though sorption to condensed water can be substantial. This favors rain sequestration as a more important atmospheric removal mechanism than dry particle sequestration. PFCAs found on particle filters during ambient sampling are thus accountable to vapor-phase PFCAs or aqueous-phase PFCAs sorbing directly to the filters, or the trapping of perfluorocarboxylate-salt particles. Further work on understanding the partitioning and speciation of PFCAs in atmospheric water droplets is needed to further quantify and understand their atmospheric behavior. To aid in this, a general RH dependent K(ip) model for surfactants is presented.

  7. Macroscopic to microscopic studies of flue gas desulfurization byproducts for acid mine drainage mitigation

    SciTech Connect

    Robbins, E.I.; Kalyoncu, R.S.; Finkelman, R.B.; Matos, G.R.; Barsotti, A.F.; Haefner, R.J.; Rowe, G.L. Jr.; Savela, C.E.; Eddy, J.I.

    1996-12-31

    The use of flue gas desulfurization (FGD) systems to reduce SO{sub 2} emissions has resulted in the generation of large quantities of byproducts. These and other byproducts are being stockpiled at the very time that alkaline materials having high neutralization potential are needed to mitigate acid mine drainage (AMD). FGD byproducts are highly alkaline materials composed primarily of unreacted sorbents (lime or limestone and sulfates and sulfites of Ca). The American Coal Ash Association estimated that approximately 20 million tons of FGD material were generated by electric power utilities equipped with wet lime-limestone PGD systems in 1993. Less than 5% of this material has been put to beneficial use for agricultural soil amendments and for the production of wallboard and cement. Four USGS projects are examining FGD byproduct use to address these concerns. These projects involve (1) calculating the volume of flue gas desulfurization (FGD) byproduct generation and their geographic locations in relation to AMD, (2) determining byproduct chemistry and mineralogy, (3) evaluating hydrology and geochemistry of atmospheric fluidized bed combustion byproduct as soil amendment in Ohio, and (4) analyzing microbial degradation of gypsum in anoxic limestone drains in West Virginia.

  8. SOXAL combined SO{sub x}/NO{sub x} flue gas control demonstration. Quarterly report, July--September 1993

    SciTech Connect

    1993-12-31

    AQUATECH Systems, a business unit of Allied-Signal Inc., proposes to demonstrate the technical viability and cost effectiveness of the SOXAL process a combined SO{sub x}/NO{sub x} control process on a 3 MW equivalent flue gas slip stream from Niagara Mohawk Power Corporation Dunkirk Steam Station Boiler No. 4, a coal fired boiler. The SOXAL process combines 90+% sulfur dioxide removal from the flue gas using a sodium based scrubbing solution and regeneration of the spent scrubbing liquor using AQUATECH Systems` proprietary bipolar membrane technology. This regeneration step recovers a stream of sulfur dioxide suitable for subsequent processing to salable sulfur or sulfuric acid. Additionally 90+% control of NO{sub x} gases can be achieved in combination with conventional urea/methanol injection of NO{sub 2} gas into the duct. The SOXAL process is applicable to both utility and industrial scale boilers using either high or lower sulfur coal. The SOXAL demonstration Program began September 10, 1991 and is approximately 26 months in duration. During the 6 months of scheduled operations, between January and July of 1993, data was collected from the SOXAL system to define: SO{sub 2} and NO{sub x} control efficiencies; Current efficiency for the regeneration unit; Sulfate oxidation in the absorber; Make-up reagent rates; Product quality including concentrations and compositions; System integration and control philosophy; and Membrane stability and performance with respect to foulants. The program is expected to be concluded in November 1993.

  9. Gas-Phase Thermal Tautomerization of Imidazole-Acetic Acid: Theoretical and Computational Investigations.

    PubMed

    Aziz, Saadullah G; Osman, Osman I; Elroby, Shaaban A; Hilal, Rifaat H

    2015-11-04

    The gas-phase thermal tautomerization reaction between imidazole-4-acetic (I) and imidazole-5-acetic (II) acids was monitored using the traditional hybrid functional (B3LYP) and the long-range corrected functionals (CAM-B3LYP and ωB97XD) with 6-311++G** and aug-cc-pvdz basis sets. The roles of the long-range and dispersion corrections on their geometrical parameters, thermodynamic functions, kinetics, dipole moments, Highest Occupied Molecular Orbital-Lowest Unoccupied Molecular Orbital (HOMO-LUMO) energy gaps and total hyperpolarizability were investigated. All tested levels of theory predicted the preference of I over II by 0.750-0.877 kcal/mol. The origin of predilection of I is assigned to the H-bonding interaction (nN8→σ*O14-H15). This interaction stabilized I by 15.07 kcal/mol. The gas-phase interconversion between the two tautomers assumed a 1,2-proton shift mechanism, with two transition states (TS), TS1 and TS2, having energy barriers of 47.67-49.92 and 49.55-52.69 kcal/mol, respectively, and an sp³-type intermediate. A water-assisted 1,3-proton shift route brought the barrier height down to less than 20 kcal/mol in gas-phase and less than 12 kcal/mol in solution. The relatively high values of total hyperpolarizability of I compared to II were interpreted and discussed.

  10. Transparent nanocellulosic multilayer thin films on polylactic acid with tunable gas barrier properties.

    PubMed

    Aulin, Christian; Karabulut, Erdem; Tran, Amy; Wågberg, Lars; Lindström, Tom

    2013-08-14

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm(3)·μm/m(2)·day·kPa at 23 °C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging.

  11. Transparent nanocellulosic multilayer thin films on polylactic acid with tunable gas barrier properties.

    PubMed

    Aulin, Christian; Karabulut, Erdem; Tran, Amy; Wågberg, Lars; Lindström, Tom

    2013-08-14

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm(3)·μm/m(2)·day·kPa at 23 °C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging. PMID:23834391

  12. Gas-Phase Thermal Tautomerization of Imidazole-Acetic Acid: Theoretical and Computational Investigations

    PubMed Central

    Aziz, Saadullah G.; Osman, Osman I.; Elroby, Shaaban A.; Hilal, Rifaat H.

    2015-01-01

    The gas-phase thermal tautomerization reaction between imidazole-4-acetic (I) and imidazole-5-acetic (II) acids was monitored using the traditional hybrid functional (B3LYP) and the long-range corrected functionals (CAM-B3LYP and ωB97XD) with 6-311++G** and aug-cc-pvdz basis sets. The roles of the long-range and dispersion corrections on their geometrical parameters, thermodynamic functions, kinetics, dipole moments, Highest Occupied Molecular Orbital–Lowest Unoccupied Molecular Orbital (HOMO–LUMO) energy gaps and total hyperpolarizability were investigated. All tested levels of theory predicted the preference of I over II by 0.750–0.877 kcal/mol. The origin of predilection of I is assigned to the H-bonding interaction (nN8→σ*O14–H15). This interaction stabilized I by 15.07 kcal/mol. The gas-phase interconversion between the two tautomers assumed a 1,2-proton shift mechanism, with two transition states (TS), TS1 and TS2, having energy barriers of 47.67–49.92 and 49.55–52.69 kcal/mol, respectively, and an sp3-type intermediate. A water-assisted 1,3-proton shift route brought the barrier height down to less than 20 kcal/mol in gas-phase and less than 12 kcal/mol in solution. The relatively high values of total hyperpolarizability of I compared to II were interpreted and discussed. PMID:26556336

  13. Evaluation of a rapid method for preparation of fatty acid methyl esters for analysis by gas-liquid chromatography.

    PubMed

    Misir, R; Laarveld, B; Blair, R

    1985-08-30

    The major limitation to fatty acid analysis by gas-liquid chromatography is associated with preparation of fatty acid methyl esters (FAME). In the present study, FAME preparations were made from plant oils (corn, olive, sunflower), sunflower oil margarine, lard and various animal tissue fats by a rapid transesterification involving tetramethylammonium hydroxide in methanol, and also by a longer conventional saponification-esterification method. Fats from animal (beef, mutton, pork) adipose tissues were extracted by a simpler modified procedure and also by the Folch method prior to the rapid and the conventional FAME preparations, respectively. FAME analysis on a gas-liquid chromatograph equipped with a Silar 10C glass capillary column indicated similar fatty acid composition of a given fat or oil, whether FAME was prepared by the rapid or the longer conventional method. The data obtained by both methods were very highly correlated for all the fats (r = 0.9895 - 0.9999). However, the rapid method showed a tendency for enhanced recoveries of lower chain fatty acids (e.g. 14:0), and also of unsaturated C18 isomers. Possibly, losses of fatty acids that occurred during the lengthy fat extraction, fatty acid esterification or ether-evaporation FAME concentration steps (conventional method) were minimised by the single transesterification step (rapid method). This rapid transesterification method appears to be an attractive alternative to FAME preparation from a wide variety of different fats for gas-liquid chromatographic analysis. PMID:4044736

  14. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    SciTech Connect

    Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.; Hedin, Robert S.; Weaver, Theodore J.; Edenborn, Harry M.

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.

  15. Gas-aerosol cycling of ammonia and nitric acid in The Netherlands

    NASA Astrophysics Data System (ADS)

    Roelofs, Geert-Jan; Derksen, Jeroen

    2010-05-01

    Atmospheric ammonia and nitric acid are present over NW Europe in large abundance. Observations made during the IMPACT measurement campaign (May 2008, Cabauw, The Netherlands) show a pronounced diurnal cycle of aerosol ammonium and nitrate on relatively dry days. Simultaneously, AERONET data show a distinct diurnal cycle in aerosol optical thickness (AOT). We used a global aerosol-climate model (ECHAM5-HAM) and a detailed aerosol-cloud column model to help analyse the observations from this period. The study shows that the diurnal cycle in AOT is partly associated with particle number concentration, with distinct peaks in the morning and evening. More important is relative humidity (RH). RH maximizes in the night and early morning, decreases during the morning and increases again in the evening. The particle wet radius, and therefore AOT, changes accordingly. In addition, the RH variability also influences chemistry associated with ammonia and nitric acid (formation of ammonium nitrate, dissolution in aerosol water), resulting in the observed diurnal cycle of aerosol ammonium and nitrate. The additional aerosol matter increases the hygroscopicity of the particles, and this leads to further swelling by water vapor condensation and a further increase of AOT. During the day, as RH decreases and the particles shrink, aerosol ammonium and nitrate are again partly expelled to the gas phase. This behaviour contributes significantly to the observed diurnal cycle in AOT, and it illustrates the complexity of using AOT as a proxy for aerosol concentrations in aerosol climate studies in the case of heavily polluted areas.

  16. Validation of an enantioselective analysis for (l)-pidolic acid by chiral gas chromatography with derivatization.

    PubMed

    Salisbury, John J; Li, Mingshu; Boyd, Aisha

    2016-02-20

    A sensitive and rapid analytical method has been validated for the enantiomeric purity determination of l-pidolic acid, a biological lactam and metabolite of glutamic acid commonly found in urine, skin, bones, brain and is available commercially as a food supplement. An efficient, two-step achiral derivatization was implemented which consisted of an alkylation step (using HCl-IPA) followed by an acylation step (using TFAA) of the carboxy and amide functional groups. This allowed detection with high sensitivity using gas chromatography with flame ionization detection. The described procedure employs a CP-Chiralsil-L Val column (25m×0.25mm) at a constant flow rate of 1.5mLmin(-1), a gradient temperature program from 80°C to 160°C and an injector and detector temperature of 250°C. The proposed method was validated according to ICH Q2 standards and included such parameters as specificity, system precision, analyst repeatability, intermediate precision, accuracy, linearity, LOD/LOQ and solution stability. PMID:26710173

  17. Fluoride accumulation by plants grown in acid soils amended with flue gas desulphurisation gypsum.

    PubMed

    Álvarez-Ayuso, E; Giménez, A; Ballesteros, J C

    2011-09-15

    The application of flue gas desulphurisation (FGD) gypsum as an acid soil ameliorant was studied in order to establish the possible detrimental effects on plants and animals feeding on them caused by the high fluoride content in this by-product. A greenhouse experiment was conducted under controlled conditions to determine the F accumulation by two plant species (alfalfa (Medicago sativa L.) and ryegrass (Lolium perenne L.)) grown in acid soils amended with different FGD gypsum doses (0-10%). The F concentrations in plant aerial parts were comprised in the range 22-65 mg kg(-1), and those in plant roots varied from 49 to 135 mg kg(-1). The F contents in the above-ground plant tissues showed to decrease with the FGD gypsum application rate, whereas an inverse trend was manifested by plant roots. The increase in the soil content of soluble Ca as a result of the FGD gypsum addition seemed to play an important role in limiting the translocation of F to plant aerial parts.

  18. Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

    PubMed

    Huang, Zhongping; Qiu, Ruofeng; Liu, Tingfei; Huang, Yilei; Zhu, Zuoyi; Wang, Lili

    2016-07-01

    An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization. A series of standard solutions of MA in the range of 1.0-50mg/kg were analyzed with correlation coefficient r≥0.9975. The limits of detection (LODs) were less than 0.15mg/kg for MA in four matrix simulants (distilled water, 3%w/v acetic acid, 10%v/v ethanol, and isooctane). Relative standard deviations (RSDs) for retention time, peak height and peak area were all less than 3.88%. The technique was successfully applied to the analysis of MA migrating from plastic cup samples, with recoveries of added MA in the range of 96.5-123.0%. Direct injection of the simulants into the GC system after migration tests, without any pretreatment step, makes the developed method of great value for rapid screening analysis of samples in bulks. PMID:27262371

  19. Profiling of soil fatty acids using comprehensive two-dimensional gas chromatography with mass spectrometry detection.

    PubMed

    Zeng, Annie Xu; Chin, Sung-Tong; Patti, Antonio; Marriott, Philip J

    2013-11-22

    Profiling of phospholipid fatty acids (PLFA) represents a challenging goal for distinguishing the diversity of microbial communities and biomass in the complex and heterogeneous soil ecosystem. Comprehensive two-dimensional gas chromatography (GC×GC) coupled with simultaneous flame ionisation and mass spectrometry detection was applied as a culture-independent method for PLFA profiling of microbial classification in forest soil. A number of column sets were evaluated for the GC×GC separation of fatty acid methyl esters (FAME). Due to better isomeric separation and compound patterns on the 2D contour plot, an apolar-polar column combination was selected for soil microbial PLFA characterisation. A comprehensive view of PLFA composition with carbon chain length varying from 12 to 20 was observed in forest soil samples, with the commonly reported bacterial FAME of iso-/anteiso-, methyl-branched-, cyclopropyl-, and hydroxyl-substituted FA identified by their mass spectral and retention time according to authentic standards. Notably, some uncommon oxygenated FAME were found in high abundance and were further characterised by GC×GC coupled with high resolution mass spectrometry. This tentatively revealed geometric pairs of methyl 9,10-epoxyoctadecanoate isomers.

  20. Perfluorosulfonic acid membrane catalysts for optical sensing of anhydrides in the gas phase.

    PubMed

    Ayyadurai, Subasri M; Worrall, Adam D; Bernstein, Jonathan A; Angelopoulos, Anastasios P

    2010-07-15

    Continuous, on-site monitoring of personal exposure levels to occupational chemical hazards in ambient air is a long-standing analytical challenge. Such monitoring is required to institute appropriate health measures but is often limited by the time delays associated with batch air sampling and the need for off-site instrumental analyses. In this work, we report on the first attempt to use the catalytic properties of perfluorosulfonic acid (PSA) membranes to obtain a rapid, selective, and highly sensitive optical response to trimellitic anhydride (TMA) in the gas phase for portable sensor device application. TMA is used as starting material for various organic products and is recognized to be an extremely toxic agent by the National Institute for Occupational Safety and Health (NIOSH). Resorcinol dye is shown to become immobilized in PSA membranes and diffusionally constrain an orange brown product that results from acid-catalyzed reaction with more rapidly diffusing TMA molecules. FTIR, UV/vis, reaction selectivity to TMA versus trimellitic acid (TMLA), and homogeneous synthesis are used to infer 5,7- dihydroxyanthraquinone-2-carboxylic acid as the acylation product of the reaction. The color response has a sensitivity to at least 3 parts per billion (ppb) TMA exposure and, in addition to TMLA, excludes maleic anhydride (MA) and phthalic anhydride (PA). Solvent extraction at long times is used to determine that the resorcinol extinction coefficient in 1100 EW PSA membrane has a value of 1210 m(2)/g at 271.01 nm versus a value of 2010 m(2)/g at 275.22 nm in 50 vol% ethanol/water solution. The hypsochromic wavelength shift and reduced extinction coefficient suggest that the polar perfluorosulfonic acid groups in the membrane provide the thermodynamic driving force for diffusion and immobilization. At a resorcinol concentration of 0.376 g/L in the membrane, a partition coefficient of nearly unity is obtained between the membrane and solution concentrations and a

  1. Evaluation of a sunscreen photoprotective effect by ascorbic acid assessment in human dermis using microdialysis and gas chromatography mass spectrometry.

    PubMed

    Lévêque, Nathalie; Mac-Mary, Sophie; Muret, Patrice; Makki, Safwat; Aubin, Francois; Kantelip, Jean-Pierre; Heusèle, Catherine; S, Schnebert; Humbert, Philippe

    2005-03-01

    Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects. PMID:15740589

  2. Electrophilic acid gas-reactive fluid, proppant, and process for enhanced fracturing and recovery of energy producing materials

    DOEpatents

    Fernandez, Carlos A.; Heldebrant, David J.; Bonneville, Alain H. R.; Jung, Hun Bok; Carroll, Kenneth

    2016-09-20

    An electrophilic acid gas-reactive fracturing and recovery fluid, proppant, and process are detailed. The fluid expands in volume to provide rapid and controlled increases in pressure that enhances fracturing in subterranean bedrock for recovery of energy-producing materials. Proppants stabilize openings in fractures and fissures following fracturing.

  3. Measuring Gas-Phase Basicities of Amino Acids Using an Ion Trap Mass Spectrometer: A Physical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Sunderlin, Lee S.; Ryzhov, Victor; Keller, Lanea M. M.; Gaillard, Elizabeth R.

    2005-01-01

    An experiment is performed to measure the relative gas-phase basicities of a series of five amino acids to compare the results to literature values. The experiments use the kinetic method for deriving ion thermochemistry and allow students to perform accurate measurements of thermodynamics in a relatively short time.

  4. Low temperature dry scrubbing reaction kinetics and mechanisms, Volume 2

    SciTech Connect

    Prudich, M.E.; Sampson, K.J.; Reddy, S.N.; Maldei, M.; Ben-Said, L. )

    1992-10-01

    A novel wet/dry desulfurization post-Furnace process (ETS' Limestone Emission control (LEC) process) for SO[sub 2] removal has been described by Prudich et al.(1988). In this process hot flue gases are contacted with a bed of quarry-sized (1/4in. to 1/32in.) wet limestone granules. This thesis represents the development of a second generation model of ETS' LEC process. The first generation model developed by Prudich et al.(1988) the use of a fixed limestone bed. The work done on this has been well documented by Appell (1989) and Visneski (1991) process under consideration for this thesis involves a continuously moving limestone bed. The moving bed simplifies the process flowsheet and facilitates limestone reactivation. The moving-bed LEC process involves the use of a cross-flow pattern with the flue gas flowing horizontally across the limestone bed at speeds of around 1 to 2 feet per second and the limestone moving vertically downward through the LEC reactor at speeds of around 1 to 15 feet per hour. The primary parameters considered in the mathematical modeling of the moving-bed LEC process are inlet sulfur dioxide concentration, inlet gas-phase water concentration, inlet flue gas and limestone temperatures and water spray addition rate over the bed. For solution of the process, mass and energy balance equations derived as a function of the positions of the flue gas limestone are solved using a predictor-corrector method. The Adams-Bashforth (modified Euler's) method is used with a second order corrector.

  5. Quantitative Organic Acids in Urine by Two Dimensional Gas Chromatography-Time of Flight Mass Spectrometry (GCxGC-TOFMS).

    PubMed

    Sweetman, Lawrence; Ashcraft, Paula; Bennett-Firmin, Jeanna

    2016-01-01

    Seventy-six organic acids in urine specimens are determined with quantitative two dimensional Gas Chromatography-Time of Flight Mass Spectrometry (GCxGC-TOFMS). The specimen is treated with urease to remove urea then derivatized to form pentafluorobenzyl oximes (PFBO) of oxoacids. The sample is then treated with ethyl alcohol to precipitate proteins and centrifuged. After drying the supernatant, the organic acids are derivatized to form volatile trimethylsilyl (TMS) derivatives for separation by capillary two dimensional Gas Chromatography (GCxGC) with temperature programming and modulation. Detection is by Time of Flight Mass Spectrometry (TOFMS) with identification of the organic acids by their mass spectra. Organic acids are quantitated by peak areas of reconstructed ion chromatograms with internal standards and calibration curves. Organic acids are quantified to determine abnormal patterns for the diagnosis of more than 100 inherited disorders of organic acid metabolism. Characteristic abnormal metabolites are quantified to monitor dietary and other modes of treatment for patients who are diagnosed with specific organic acid disorders.

  6. NOx scrubbing at ORNL

    SciTech Connect

    Pearson, T. E.; Counce, R. M.

    1980-01-01

    Concern over the level of emission of nitrogen oxides (NO/sub x/) from nuclear fuel reprocessing facilities has focused the efforts of research, development and engineering on ways of reducing their concentration in off-gas streams. Research began back in January of 1976. A scrubber design which incorporated the research work began in mid September of 1978. The scrubber is presently being fabricated and will become a part of the Integrated Process Demonstration (IPD) facility. This paper will present an introduction to the chemistry of NO/sub x/ and will discuss the problems associated with its removal from off-gas streams. The IPD NO/sub x/ off-gas system components will be presented and the system interfaces with the other IPD systems will be shown. The computer model used to design the scrubber will be discussed and the results from the program will be presented. The paper will conclude with a brief description of other scrubber applications and will mention areas of continuing research.

  7. Gas phase C{sub 2}-C{sub 10} organic acids concentrations in the Los Angeles atmosphere

    SciTech Connect

    Nolte, C.G.; Fraser, M.P.; Cass, G.R.

    1999-02-15

    The atmospheric concentrations of gas-phase C{sub 2}--C{sub 10} monocarboxylic and benzoic acids are reported in samples collected during a severe Los Angeles area photochemical smog episode. Average urban concentrations are 10--50 {times} greater than concentrations observed at a remote background location, indicating an anthropogenic origin for these compounds. Average urban concentrations during the episode were 16.1 {micro}g m{sup {minus}3} (6.6 ppb) for acetic acid and 1.67 {micro}g m{sup {minus}3} (0.55 ppb) for propionic acid, with progressively lesser amounts as the carbon chain length of the acids is increased. Spatial and diurnal variations in atmospheric organic acids concentrations point to the importance of both direct emissions from primary sources and formation by photochemical reaction of precursor compounds.

  8. Characterization of Benthic Microbial Community Structure by High-Resolution Gas Chromatography of Fatty Acid Methyl Esters

    PubMed Central

    Bobbie, Ronald J.; White, David C.

    1980-01-01

    Fatty acids are a widely studied group of lipids of sufficient taxonomic diversity to be useful in defining microbial community structure. The extraordinary resolution of glass capillary gas-liquid chromatography can be utilized to separate and tentatively identify large numbers of fatty acid methyl esters derived from the lipids of estuarine detritus and marine benthic microbiota without the bias of selective methods requiring culture or recovery of the microbes. The gas-liquid chromatographic analyses are both reproducible and highly sensitive, and the recovery of fatty acids is quantitative. The analyses can be automated, and the diagnostic technique of mass spectral fragmentation analysis can be readily applied. Splitless injection on glass capillary gas chromatographic columns detected by mass spectral selective ion monitoring provides an ultrasensitive and definitive monitoring system. Reciprocal mixtures of bacteria and fungi, when extracted and analyzed, showed progressive changes of distinctive fatty acid methyl esters derived from the lipids. By manipulating the environment of an estuarine detrital microbial community with antibiotics and culture conditions, it was possible to produce a community greatly enriched in eucaryotic fungi, as evidenced by scanning electron microscopic morphology. The fatty acid methyl esters from the lipids in the fungus-enriched detritus showed enrichment of the C18 dienoic and the C18 and C20 polyenoic esters. Manipulation of the detrital microbiota that increased the procaryotic population resulted in an absence of large structures typical of fungal mycelia or diatoms, as evidenced by scanning electron microscopy, and a significantly larger proportion of anteiso- and isobranched C15 fatty acid esters, C17 cyclopropane fatty acid esters, and the cis-vaccenic isomer of the C18 monoenoic fatty acid esters. As determined by these techniques, a marine settling community showed greater differences in bacterial as contrasted to

  9. Determination of short-chain fatty acids in serum by hollow fiber supported liquid membrane extraction coupled with gas chromatography.

    PubMed

    Zhao, Guohua; Liu, Jing-Fu; Nyman, Margareta; Jönsson, Jan Ake

    2007-02-01

    A method based on hollow fiber supported liquid membrane extraction coupled with a gas chromatograph equipped with flame ionization detector (GC-FID) was developed for the determination of six short-chain fatty acids including acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid and n-valeric acid in serum. Hollow fiber supported liquid membrane extraction was employed for preconcentration and clean-up of the samples. The fatty acids were extracted from the acidic donor (diluted serum) into a liquid membrane formed in the wall of the hollow fiber with 10% tri-n-octylphoshphine oxide (TOPO) in di-n-hexyl ether, and then extracted back into a basic acceptor solution filled in the lumen of the hollow fiber. After being acidified with HCl, the acceptor was directly analyzed by GC-FID. The acceptor concentration, donor pH, membrane liquid and extracting time were optimized giving an enrichment factor up to 155 times. The good linearity (r(2)>0.980), reasonable recovery (87.2-121%), and satisfactory intra-assay (8.2-11.5%) and inter-assay (6.1-11.6%) precision illustrated the good performance of the present method. Limits of detection (LOD) ranged from 0.04 to 0.24 microM and limits of quantification (LOQ) varied from 0.13 to 0.80 microM. PMID:17070116

  10. Conformational preferences of γ-aminobutyric acid in the gas phase and in water

    NASA Astrophysics Data System (ADS)

    Song, Il Keun; Kang, Young Kee

    2012-09-01

    The conformational study of γ-aminobutyric acid (GABA) has been carried out at the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water. In the gas phase, the folded conformation gG1 with gauche- and gauche+ conformations for the Cβsbnd Cα and Cγsbnd Cβ bonds, respectively, is found to be lowest in energy and enthalpy, which can be ascribed to the favored hyperconjugative n → π* interaction between the lone electron pair of the amine nitrogen atom and the Cdbnd O bond of the carboxylic group and the favored antiparallel dipole-dipole interaction between the Nsbnd H bond and the Cdbnd O bond. In addition, the intramolecular hydrogen bonds between the carboxylic group and the amine Nsbnd H group have contributed to stabilize some low-energy conformers. However, the most preferred conformation is found to be tG1 and more stable by 0.4 kcal/mol in ΔG than the conformer gG1, in which the favored entropic term due to the conformational flexibility and the other favored n → σ*, σ → σ*, and π → σ* interactions seem to play a role. The conformational preferences of the neutral GABA calculated by ΔG's are reasonably consistent with the populations deduced from FT microwave spectroscopy in supersonic jets combined with laser ablation. In water, the two folded conformers Gg and gG of the zwitterionic GABA are dominantly populated, each of which has the population of 47%, and the hydrogen bond between the ammonium Nsbnd H group and the lone electron pair of the Csbnd O- group seems to be crucial in stabilizing these conformers. Our calculated result that the folded conformers preferentially exist in water is consistent with the 1H NMR experiments in D2O.

  11. Gas/particle partitioning of low-molecular-weight dicarboxylic acids at a suburban site in Saitama, Japan

    NASA Astrophysics Data System (ADS)

    Bao, Linfa; Matsumoto, Mariko; Kubota, Tsutomu; Sekiguchi, Kazuhiko; Wang, Qingyue; Sakamoto, Kazuhiko

    2012-02-01

    Low-molecular-weight dicarboxylic acids (diacids) exhibit semivolatile behavior in the atmosphere, but their partitioning between the gaseous and particulate phases is still unclear. An annular denuder-filter pack system with a cyclone PM 2.5 was employed to investigate the gaseous and particulate phase concentrations of diacids, with high collection efficiency of most target compounds. Saturated diacids, unsaturated diacids, ketocarboxylic acids, and dicarbonyls were determined in gaseous and particulate samples collected from a suburban site in Japan, during 2007 summer, 2008 late-winter and early-winter. The concentrations of gaseous and particulate diacids in early-winter were lower than those in summer, but higher than those in late-winter. Individual diacid in gaseous phase showed a relatively good correlation with ambient oxidants, but a low correlation with NO gas (a primary pollutant). Particulate fraction to the total amount ( FP) of individual acid was larger in winter than in summer, and also was larger at night than in the daytime. In the same sample, individual diacid and ketocarboxylic acid had higher particulate phase occurrence ( FP > 56% in summer), whereas unsaturated diacid had higher gaseous phase occurrence ( FP < 18% in summer). In summer, gas/particle partitioning of diacids varied diurnally; FP values of oxalic and glyoxylic acids increased from their lowest values in the morning to their highest values at night, exhibiting the similar diurnal variation of relative humidity in the atmosphere. The higher humidity at night may lead to the formation of droplets in which water-soluble gaseous phases can dissolve, thus promoting gas-to-particle conversion. These results suggest that gas/particle partitioning of diacids depends not only on the concentrations in the gaseous phase by photochemical oxidation, but also on the characteristics of the atmosphere (e.g., temperature, sunlight, and relative humidity) and the aerosols (e.g., acidity

  12. Low temperature dry scrubbing reaction kinetics and mechanisms: Volume 2

    SciTech Connect

    Prudich, M.E.; Sampson, K.J.; Visneski, M.J.; Reddy, S.N.; Ben-Said, L.; Maldei, M. )

    1992-03-01

    A resistance-in-series kinetic model for the low temperature reaction of sulfur dioxide with limestone is presented. The resistances considered are the gas-phase transport of sulfur dioxide, the liquid-phase diffusion of both the sulfur species and the calcium species and the solid-phase dissolution of limestone. The model uses film theory to predict the liquid concentrations of the dissolved species and assumes an instantaneous reaction between the sulfur species and calcium species. The kinetic model incorporates three rate equations for the removal of sulfur dioxide. When the rate of removal is limited by the diffusion of sulfur dioxide across the gas film surrounding the limestone particle, a gas-phase controlled rate equation is used. When the diffusion of the reacting species through the liquid film covering the limestone particle is the predominant resistance, a liquid-phase controlled rate equation is used. When the rate is limited by the dissolution of limestone, a solid-phase controlled rate equation is used. The kinetic model is incorporated into a flow model for the fixed-bed Limestone Emission Control (LEC) system. The LEC system employs a fixed-bed of standard quarry-sized limestone to remove sulfur dioxide from coal-fired boiler flue gases. The flow modeling equations for the fixed-bed LEC system, which include simultaneous heat and mass transfer as applied to water-phase evaporation and condensation are also presented. The combined kinetic and flow model is subjected to a parametric study and the modeling predictions are compared with experimental results.

  13. Shawnee flue gas desulfurization computer model users manual

    SciTech Connect

    Sudhoff, F.A.; Torstrick, R.L.

    1985-03-01

    In conjunction with the US Enviromental Protection Agency sponsored Shawnee test program, Bechtel National, Inc., and the Tennessee Valley Authority jointly developed a computer model capable of projecting preliminary design and economics for lime- and limestone-scrubbing flue gas desulfurization systems. The model is capable of projecting relative economics for spray tower, turbulent contact absorber, and venturi-spray tower scrubbing options. It may be used to project the effect on system design and economics of variations in required SO/sub 2/ removal, scrubber operating parameters (gas velocity, liquid-to-gas (L/G) ration, alkali stoichiometry, liquor hold time in slurry recirculation tanks), reheat temperature, and scrubber bypass. It may also be used to evaluate alternative waste disposal methods or additives (MgO or adipic acid) on costs for the selected process. Although the model is not intended to project the economics of an individual system to a high degree of accuracy, it allows prospective users to quickly project comparative design and costs for limestone and lime case variations on a common design and cost basis. The users manual provides a general descripton of the Shawnee FGD computer model and detailed instructions for its use. It describes and explains the user-supplied input data which are required such as boiler size, coal characteristics, and SO/sub 2/ removal requirments. Output includes a material balance, equipment list, and detailed capital investment and annual revenue requirements. The users manual provides information concerning the use of the overall model as well as sample runs to serve as a guide to prospective users in identifying applications. The FORTRAN-based model is maintained by TVA, from whom copies or individual runs are available. 25 refs., 3 figs., 36 tabs.

  14. Investigating the Weak to Evaluate the Strong: An Experimental Determination of the Electron Binding Energy of Carborane Anions and the Gas phase Acidity of Carborane Acids

    SciTech Connect

    Meyer, Matthew M; Wang, Xue B; Reed, Christopher A; Wang, Lai S; Kass, Steven R

    2009-12-23

    Five CHB11X6Y5- carborane anions from the series X = Br, Cl, I and Y = H, Cl, CH3 were generated by electrospray ionization, and their reactivity with a series of Brønsted acids and electron transfer reagents were examined in the gas phase. The undecachlorocarborane acid, H(CHB11Cl11), was found to be far more acidic than the former record holder, (1-C4F9SO2)2NH (i.e., ΔH°acid = 241 ± 29 vs 291.1 ± 2.2 kcal mol-1) and bridges the gas-phase acidity and basicity scales for the first time. Its conjugate base, CHB11Cl11-, was found by photoelectron spectroscopy to have a remarkably large electron binding energy (6.35 ± 0.02 eV) but the value for the (1-C4F9SO2)2N- anion is even larger (6.5 ± 0.1 eV). Consequently, it is the weak H-(CHB11Cl11) BDE (70.0 kcal mol-1, G3(MP2)) compared to the strong BDE of (1-C4F9SO2)2N-H (127.4 ± 3.2 kcal mol-1) that accounts for the greater acidity of carborane acids.

  15. Losses told from scrubbing nukes: survey details utility accounting practices

    SciTech Connect

    Not Available

    1980-10-01

    Reduced load forecasts and the Three Mile Island accident led to a record number of nuclear power plant cancellations in 1980, according to a survey of reporting and accounting methods of 60 large electric utilities and 25 gas and water companies. The utilities are trying to recover losses through increased rates, but most are employing accounting methods to defer their losses by using the allowance for funds used during construction (AFUDC). The companies report treating the AFUDC funds in different ways, the majority deducting them from income and construction as a noncash item. (DCK)

  16. Metal regeneration of iron chelates in nitric oxide scrubbing

    DOEpatents

    Chang, Shih-Ger; Littlejohn, David; Shi, Yao

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH.sub.3. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20.degree. and 90.degree. C. to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution.

  17. Metal regeneration of iron chelates in nitric oxide scrubbing

    DOEpatents

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  18. Combustion Instability in an Acid-Heptane Rocket with a Pressurized-Gas Propellant Pumping System

    NASA Technical Reports Server (NTRS)

    Tischler, Adelbert O.; Bellman, Donald R.

    1951-01-01

    Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis. The pressure-fluctuation frequency for a rocket engine with a characteristic length of 100 inches and operated at a combustion-chamber pressure of 280 pounds per square inch absolute was 38 cycles per second; the analysis indicated. a frequency of 37 cycles per second. Increasing combustion-chamber characteristic length decreased the pressure-fluctuation frequency, in conformity to the analysis. Increasing the chamber operating pressure or increasing the injector pressure drop increased the frequency. These latter two effects are contrary to the analysis; the discrepancies are attributed to the conflict between the assumptions made to simplify the analysis and the experimental conditions. Oxidant-fuel ratio had no apparent effect on the experimentally measured pressure-fluctuation frequency for acid-heptane ratios from 3.0 to 7.0. The frequencies decreased with increased amplitude of the combustion-chamber pressure variations. The analysis indicated that if the combustion time delay were sufficiently short, low-frequency combustion instability would be eliminated.

  19. Effectiveness of Internal vs. External SEU Scrubbing Mitigation Strategies in a Xilinx FPGA: Design, Test, and Analysis

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Poivey C.; Petrick, D.; Espinosa, D.; Lesea, Austin; LaBel, K. A.; Friendlich, M; Kim, H; Phan, A.

    2008-01-01

    We compare two scrubbing mitigation schemes for Xilinx FPGA devices. The design of the scrubbers is briefly discussed along with an examination of mitigation limitations. Proton and Heavy Ion data are then presented and analyzed.

  20. Techniques of ground-truth measurements of desert-scrub structure

    NASA Technical Reports Server (NTRS)

    Ottermann, J.; Deering, D.; Eck, T.; Ringrose, S.

    1987-01-01

    Inversion of remote sensing data taken over a desert scrub surface in Texas with a multidirectionally viewing field radiometer, PARABOLA, yields the value of 0.12 for the protrusion parameter, s, (the projection on a vertical plane of plants per unit area) if isotropy (Lambert law) is assumed for the underlying soil. However, a significantly higher value of s, in the range 0.15 to 0.20, can be inferred if the soil is assumed anisotropic. It is concluded that in remote sensing of sparse vegetation, it is important to know the reflectance characteristics of the underlying soil. Other techniques that can be used to infer desert scrub vegetation structure include various photographic techniques, and measurements of reflected radiance from zenith for a range of solar elevation angles on a clear day.

  1. Mapping Florida Scrub Jay habitat for purposes of land-use management

    NASA Technical Reports Server (NTRS)

    Breininger, David R.; Provancha, Mark J.; Smith, Rebecca B.

    1991-01-01

    Geographical information system (GIS) applications were used to map areas of primary and secondary Florida Scrub Jay habitat on Kennedy Space Center (KSC) using vegetation and soils maps. Data from field studies were used for accuracy assessment and evaluating the importance of mapping classes. Primary habitat accounts for 15 percent of the potential habitat and contained 57 percent of the Florida Scrub Jay population on KSC. Proximity analysis identified potential population centers, which were 44 percent of the potential habitat and contained 86 percent of the population. This study is an example of how remote sensing and GIS applications can provide information for land-use planning, habitat management, and the evaluation of cumulative impacts.

  2. Sacral Herpes Zoster Associated with Voiding Dysfunction in a Young Patient with Scrub Typhus.

    PubMed

    Hur, Jian

    2015-06-01

    When a patient presents with acute voiding dysfunction without a typical skin rash, it may be difficult to make a diagnosis of herpes zoster. Here, we present a case of scrub typhus in a 25-year-old man with the complication of urinary dysfunction. The patient complained of loss of urinary voiding sensation and constipation. After eight days, he had typical herpes zoster eruptions on the sacral dermatomes and hypalgesia of the S1-S5 dermatomes. No cases of dual infection with varicella zoster virus and Orientia tsutsugamushi were found in the literature. In the described case, scrub typhus probably induced sufficient stress to reactivate the varicella zoster virus. Early recognition of this problem is imperative for prompt and appropriate management, as misdiagnosis can lead to long-term urinary dysfunction. It is important that a diagnosis of herpes zoster be considered, especially in patients with sudden onset urinary retention.

  3. A comparison of avian hematozoan epizootiology in two California coastal scrub communities

    USGS Publications Warehouse

    Super, Paul E.; van Riper, Charles, III

    1995-01-01

    Passerine birds within two California (USA) coastal scrub ecosystems, an island and a mainland site, were examined for hematozoa from 1984 to 1990. Island birds had a significantly lower hematozoan prevalence than mainland birds. This prevalence difference can be related to a lack of appropriate hematozoan vectors on the island. Haemoproteus spp. and Leucocytozoon spp. were the most commonly encountered hematozoa; four new species of Leucocytozoon spp. and one new Haemoproteus sp. were found in five host families. No transmission of hematozoan parasites was detected at the island site during the study. At the mainland coastal scrub site, Leucocytozoon spp. was transmitted each year while Plasmodium spp. and Haemoproteus spp. transmission varied between years. There was evidence that some species of birds acquired infections outside of their breeding season. Results of this study lend further support to the prediction of decreased disease on remote island ecosystems.

  4. Scrub typhus vaccine candidate Kp r56 induces humoral and cellular immune responses in cynomolgus monkeys.

    PubMed

    Chattopadhyay, Suchismita; Jiang, Ju; Chan, Teik-Chye; Manetz, T Scott; Chao, Chien-Chung; Ching, Wei-Mei; Richards, Allen L

    2005-08-01

    A truncated recombinant 56-kDa outer membrane protein of the Karp strain of Orientia tsutsugamushi (Kp r56) was evaluated in cynomolgus monkeys (Macaca fascicularis) for immunogenicity and safety as a vaccine candidate for the prevention of scrub typhus. This recombinant antigen induced strong humoral and cellular immune responses in two monkeys and was found to be well tolerated. Antigen-specific immunoglobulin M (IgM) and IgG were produced to almost maximal levels within 1 week of a single immunization. Peripheral blood mononuclear cells from vaccinated animals showed an induction of antigen-specific proliferation and gamma interferon production. The Kp r56 was not as efficient as infection with live organisms in preventing reinfection but was able to reduce the inflammation produced at the site of challenge. This report describes the results of the first systematic study of the immunogenicity of a recombinant scrub typhus vaccine candidate in a nonhuman primate model.

  5. On the phylogenetic position of the scrub-birds (Passeriformes: Menurae: Atrichornithidae) of Australia

    USGS Publications Warehouse

    Chesser, R.T.; ten, Have J.

    2007-01-01

    Evolutionary relationships of the scrub-birds Atrichornis were investigated using complete sequences of the recombination-activating gene RAG-1 and the proto-oncogene c-mos for two individuals of the noisy scrub-bird Atrichornis clamosus. Phylogenetic analysis revealed that Atrichornis was sister to the genus Menura (the lyrebirds) and that these two genera (the Menurae) were sister to the rest of the oscine passerines. A sister relationship between Atrichornis and Menura supports the traditional view, based on morphology and DNA hybridization, that these taxa are closely related. Similarly, a sister relationship with the remaining oscine passerines agrees with the morphological distinctiveness of Atrichornis and Menura, although this result contradicts conclusions based on DNA hybridization studies. Although Atrichornis is very well known morphologically, previous conclusions regarding its relationships were hampered by a lack of comparative knowledge of other passerines, making concurrence of the sequence data of particular significance. ?? Dt. Ornithologen-Gesellschaft e.V. 2007.

  6. Competitive threshold collision-induced dissociation: Gas-phase acidities and bond dissociation energies for a series of alcohols

    SciTech Connect

    DeTuri, V.F.; Ervin, K.M.

    1999-09-02

    Energy-resolved competitive collision-induced dissociation methods are used to measure the gas-phase acidities of a series of alcohols (methanol, ethanol, 2-propanol, and 2-methyl-2-propanol). The competitive dissociation reactions of fluoride-alcohol, [F{sup {minus}}{center{underscore}dot}HOR], alkoxide-water, [RO{sup {minus}}{center{underscore}dot}HOH], and alkoxide-methanol [RO{+-}{center{underscore}dot}HOCH{sub 3}] proton-bound complexes are studied using a guided ion beam tandem mass spectrometer. The reaction cross sections and product branching fractions to the two proton transfer channels are measured as a function of collision energy. The enthalpy difference between the two product channels is found by modeling the reaction cross sections near threshold using RRKM theory to account for the energy-dependent product branching ratio and kinetic shift. From the enthalpy difference, the alcohol gas-phase acidities are determined relative to the well-known values of HF and H{sub 2}O. The measured gas-phase acidities are {Delta}{sub acid}H{sub 298}(CH{sub 3}OH) = 1599 {+-} 3 kJ/mol, {Delta}{sub acid}H{sub 298}(CH{sub 3}CH{sub 2}OH) = 1586 {+-} 5 kJ/mol, {Delta}{sub acid}H{sub 298}((CH{sub 3}){sub 2}CHOH) = 1576 {+-} 4 kJ/mol, and {Delta}{sub acid}H{sub 298}((CH{sub 3}){sub 3}COH) = 1573 {+-} 3 kJ/mol.

  7. Effect of gas composition on the NOx conversion chemistry in a plasma

    SciTech Connect

    McLarnon, C R; Penetrante, B M

    1998-08-24

    Much work has been done on the application of plasmas to the treatment of NOx from power plants. In power plant applications, the purpose of the plasma is to oxidize NO to NOx, and eventually to nitric acid. The desires products, in the form of ammonium salts, are then obtained by mixing ammonia with the formed acids. Some form of scrubbing is required to collect the final products. For applications to the treatment of exhausts from cars and trucks, it is very important to make a distinction between NO removal by chemical oxidation and NO removal by chemical reduction. To avoid the need for scrubbing of plasma processing products, the desired method of NO removal is by chemical reduction; i.e., the conversion of NO to benign gaseous products like N NO2. This paper will discuss the results of an extensive series of experiments aimed towards understanding the effect of gas composition on the NOx conversion chemistry in a plasma. The NOx conversion chemistry in the presence of the individual components, such as N2, O2, H2O, and CO2, as well as the mixture of these, will be presented. We will show that, in a lean-burn gasoline or diesel engine exhaust, the main effect of the gas-phase reactions in a plasma is the oxidation of NO to NOx and nitric acid. To implement the reduction of NOx to N2 in the highly oxidizing environment of a lean-burn engine exhaust, it will be necessary to prevent the formation of acid products and combine the plasma with another process that can chemically reduce NO2 to Nx.

  8. STS-88 crew returns to the O&C Bldg. after the launch scrub

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Despite the launch scrub of Space Shuttle Mission STS-88, Commander Robert D. Cabana has a big smile as he returns to the crew quarters in the Operations and Checkout Building. Behind him in the astronaut van is Pilot Frederick W. 'Rick' Sturckow. The Space Shuttle Endeavour is slated to make another liftoff attempt on Friday, Dec. 4, for the first U.S. mission dedicated to the assembly of the International Space Station.

  9. Q Fever, Scrub Typhus, and Rickettsial Diseases in Children, Kenya, 2011–2012

    PubMed Central

    Farris, Christina M.; Odhiambo, Antony; Jiang, Ju; Laktabai, Jeremiah; Armstrong, Janice; Holland, Thomas; Richards, Allen L.; O’Meara, Wendy P.

    2016-01-01

    To increase knowledge of undifferentiated fevers in Kenya, we tested paired serum samples from febrile children in western Kenya for antibodies against pathogens increasingly recognized to cause febrile illness in Africa. Of patients assessed, 8.9%, 22.4%, 1.1%, and 3.6% had enhanced seroreactivity to Coxiella burnetii, spotted fever group rickettsiae, typhus group rickettsiae, and scrub typhus group orientiae, respectively. PMID:27088502

  10. An Intradermal Inoculation Mouse Model for Immunological Investigations of Acute Scrub Typhus and Persistent Infection

    PubMed Central

    Rockx-Brouwer, Dedeke; Xu, Guang; Goez-Rivillas, Yenny; Drom, Claire; Shelite, Thomas R.; Valbuena, Gustavo; Walker, David H.; Bouyer, Donald H.

    2016-01-01

    Scrub typhus is a neglected tropical disease, caused by Orientia tsutsugamushi, a Gram-negative bacterium that is transmitted to mammalian hosts during feeding by Leptotrombidium mites and replicates predominantly within endothelial cells. Most studies of scrub typhus in animal models have utilized either intraperitoneal or intravenous inoculation; however, there is limited information on infection by the natural route in murine model skin or its related early host responses. Here, we developed an intradermal (i.d.) inoculation model of scrub typhus and focused on the kinetics of the host responses in the blood and major infected organs. Following ear inoculation with 6 x 104 O. tsutsugamushi, mice developed fever at 11–12 days post-infection (dpi), followed by marked hypothermia and body weight loss at 14–19 dpi. Bacteria in blood and tissues and histopathological changes were detected around 9 dpi and peaked around 14 dpi. Serum cytokine analyses revealed a mixed Th1/Th2 response, with marked elevations of MCP-1/CCL2, MIP-1α/CCL3 and IL-10 at 9 dpi, followed by increased concentrations of pro-inflammatory markers (IL-6, IL-12, IFN-γ, G-CSF, RANTES/CCL5, KC/CCL11, IL-1α/β, IL-2, TNF-α, GM-CSF), as well as modulatory cytokines (IL-9, IL-13). Cytokine levels in lungs had similar elevation patterns, except for a marked reduction of IL-9. The Orientia 47-kDa gene and infectious bacteria were detected in several organs for up to 84 dpi, indicating persistent infection. This is the first comprehensive report of acute scrub typhus and persistent infection in i.d.-inoculated C57BL/6 mice. This is a significant improvement over current murine models for Orientia infection and will permit detailed studies of host immune responses and infection control interventions. PMID:27479584

  11. Determination of Cutoff of ELISA and Immunofluorescence Assay for Scrub Typhus

    PubMed Central

    Gupta, Nitin; Chaudhry, Rama; Thakur, Chandan Kumar

    2016-01-01

    Background: The most common method employed for diagnosis of scrub typhus is serology. It is widely known that demonstration of ≥4-fold rise in titers of antibody in paired sera is required for diagnosis. However, for guidance of initial treatment, there is a need for rapid diagnosis at the time of admission. Therefore, there is a need for standardized region specific cutoff titers at the time of admission. Materials and Methods: A total of 258 patients of all age groups with clinically suspected scrub typhus over a period of 24 months (October 2013-October 2015) were enrolled. Serum samples of these patients were subjected to immunofluorescent antibody (IFA) for immunoglobulin M (IgM) (Fuller Labs, USA) with dilutions of 1:64, 1:128, 1:256, and 1:512. Serum samples of all 258 patients were subjected to IgM ELISA (Inbios Inc., USA). Any patient with response to antibiotics within 48 h accompanied by either presence of an eschar or positivity by polymerase chain reaction was taken as positive. Receiver operating characteristic (ROC) curve was drawn to generate cutoff for these tests. Results: A total of 20 patients were diagnosed as cases of scrub typhus. The ROC curve analysis revealed a cutoff optical density value of 0.87 with sensitivity and specificity of 100% and 94.12%, respectively. ROC curve analysis of IFA revealed sensitivity and specificity of 100% and 93.5%, respectively at 1:64 dilution. Conclusion: Considering cost constraints, centers in and around New Delhi region can use the cutoffs we determined for the diagnosis of scrub typhus. PMID:27621559

  12. Determination of Cutoff of ELISA and Immunofluorescence Assay for Scrub Typhus

    PubMed Central

    Gupta, Nitin; Chaudhry, Rama; Thakur, Chandan Kumar

    2016-01-01

    Background: The most common method employed for diagnosis of scrub typhus is serology. It is widely known that demonstration of ≥4-fold rise in titers of antibody in paired sera is required for diagnosis. However, for guidance of initial treatment, there is a need for rapid diagnosis at the time of admission. Therefore, there is a need for standardized region specific cutoff titers at the time of admission. Materials and Methods: A total of 258 patients of all age groups with clinically suspected scrub typhus over a period of 24 months (October 2013-October 2015) were enrolled. Serum samples of these patients were subjected to immunofluorescent antibody (IFA) for immunoglobulin M (IgM) (Fuller Labs, USA) with dilutions of 1:64, 1:128, 1:256, and 1:512. Serum samples of all 258 patients were subjected to IgM ELISA (Inbios Inc., USA). Any patient with response to antibiotics within 48 h accompanied by either presence of an eschar or positivity by polymerase chain reaction was taken as positive. Receiver operating characteristic (ROC) curve was drawn to generate cutoff for these tests. Results: A total of 20 patients were diagnosed as cases of scrub typhus. The ROC curve analysis revealed a cutoff optical density value of 0.87 with sensitivity and specificity of 100% and 94.12%, respectively. ROC curve analysis of IFA revealed sensitivity and specificity of 100% and 93.5%, respectively at 1:64 dilution. Conclusion: Considering cost constraints, centers in and around New Delhi region can use the cutoffs we determined for the diagnosis of scrub typhus.

  13. Q Fever, Scrub Typhus, and Rickettsial Diseases in Children, Kenya, 2011-2012.

    PubMed

    Maina, Alice N; Farris, Christina M; Odhiambo, Antony; Jiang, Ju; Laktabai, Jeremiah; Armstrong, Janice; Holland, Thomas; Richards, Allen L; O'Meara, Wendy P

    2016-05-01

    To increase knowledge of undifferentiated fevers in Kenya, we tested paired serum samples from febrile children in western Kenya for antibodies against pathogens increasingly recognized to cause febrile illness in Africa. Of patients assessed, 8.9%, 22.4%, 1.1%, and 3.6% had enhanced seroreactivity to Coxiella burnetii, spotted fever group rickettsiae, typhus group rickettsiae, and scrub typhus group orientiae, respectively. PMID:27088502

  14. Removal of sulfur dioxide from flue gas

    SciTech Connect

    Gorin, E.

    1980-06-17

    An improvement is provided in the regeneration system of aqueous regenerative processes for the removal of SO/sub 2/ from SO/sub 2/-containing gas streams which have a scrubbing system containing (1) a scrubbing zone through which a recirculating stream of sodium or potassium thiosulfate solution continuously passes as a vehicle for the SO/sub 2/ absorbent, sodium or potassium carbonate, under conditions favorable to the formation of sulfite by the reaction of carbonate and SO/sub 2/ and (2) a thiosulfate generation zone in which the sulfite is converted by reaction with a sulfide to thiosulfate. The improvement comprises converting, in a regeneration system, the net make of thiosulfate to a mixture of sulfide and carbonate by first converting the thiosulfate to sulfate, then reducing the sulfate to sulfide; and thereafter partially carbonating the sulfide to form a mixture of sulfide and carbonate for return to the scrubbing system.

  15. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation.

    PubMed

    Donaldson, D James; Kroll, Jay A; Vaida, Veronica

    2016-07-15

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 ((3)B1), which may be accessed by near-UV solar excitation of SO2 to its excited (1)B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF).

  16. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation

    NASA Astrophysics Data System (ADS)

    Donaldson, D. James; Kroll, Jay A.; Vaida, Veronica

    2016-07-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF).

  17. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation

    PubMed Central

    Donaldson, D. James; Kroll, Jay A.; Vaida, Veronica

    2016-01-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF). PMID:27417675

  18. Optimizing Techology to Reduce Mercury and Acid Gas Emissions from Electric Power Plants

    SciTech Connect

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon

    2004-01-31

    More than 56,000 coal quality data records from five public data sets have been selected for use in this project. These data will be used to create maps showing where coals with low mercury and acid-gas emissions might be found for power plants classified by air-pollution controls. Average coal quality values, calculated for 51,156 commercial coals by U.S. county-of-origin, are listed in the appendix. Coal moisture values are calculated for commercially shipped coal from 163 U.S. counties, where the raw assay data (including mercury and chlorine values) are reported on a dry basis. The calculated moisture values are verified by comparison with observed moisture values in commercial coal. Moisture in commercial U.S. coal shows provincial variation. For example, high volatile C bituminous rank coal from the Interior province has 3% to 4% more moisture than equivalent Rocky Mountain province coal. Mott-Spooner difference values are calculated for 4,957 data records for coals collected from coal mines and exploration drill holes. About 90% of the records have Mott-Spooner difference values within {+-}250 Btu/lb.

  19. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation.

    PubMed

    Donaldson, D James; Kroll, Jay A; Vaida, Veronica

    2016-01-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 ((3)B1), which may be accessed by near-UV solar excitation of SO2 to its excited (1)B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF). PMID:27417675

  20. Advanced Acid Gas Separation Technology for the Utilization of Low Rank Coals

    SciTech Connect

    Kloosterman, Jeff

    2012-12-31

    Air Products has developed a potentially ground-breaking technology – Sour Pressure Swing Adsorption (PSA) – to replace the solvent-based acid gas removal (AGR) systems currently employed to separate sulfur containing species, along with CO{sub 2} and other impurities, from gasifier syngas streams. The Sour PSA technology is based on adsorption processes that utilize pressure swing or temperature swing regeneration methods. Sour PSA technology has already been shown with higher rank coals to provide a significant reduction in the cost of CO{sub 2} capture for power generation, which should translate to a reduction in cost of electricity (COE), compared to baseline CO{sub 2} capture plant design. The objective of this project is to test the performance and capability of the adsorbents in handling tar and other impurities using a gaseous mixture generated from the gasification of lower rank, lignite coal. The results of this testing are used to generate a high-level pilot process design, and to prepare a techno-economic assessment evaluating the applicability of the technology to plants utilizing these coals.

  1. Direct effects of nitroprusside do not alter gas exchange in canine oleic acid edema.

    PubMed

    Angle, M; Ducas, J; Schick, U; Girling, L; Prewitt, R M

    1984-11-01

    The authors investigated why intrapulmonary shunt (QS/QT) increases with sodium nitroprusside (SNP) in canine oleic acid pulmonary edema. To determine the effects of flow alone on QS/QT, a peripheral arteriovenous fistula with a variable resistor was employed to increase cardiac output (Q) 26 and 52% above base line in a stepwise fashion (P less than 0.01). To examine the direct effects of SNP, distinct from changes in flow, the drug was given to produce matched increments in Q in each dog (P less than 0.01). To control for time, base-line measurements were obtained before and after each intervention, the sequence of which was alternated. At each increment in Q, SNP and the arteriovenous fistula increased QS/QT a similar amount. The mixed venous O2 tension (P-vO2) followed Q similarly in each group. Pulmonary vascular resistance (PVR) fell more (P less than 0.01) with SNP than with the arteriovenous fistula at identical Q and P-vO2. The authors conclude that, in this model, a direct pharmacological effect of SNP does not contribute to the deterioration in QS/QT. In fact, SNP exerts a pulmonary vasoactive effect that does not adversely affect gas exchange. PMID:6520043

  2. Penetration of methyl isocyanate through organic vapor and acid gas respirator cartridges

    SciTech Connect

    Moyer, E.S.; Berardinelli, S.P.

    1987-04-01

    Methyl isocyanate (MIC) is a volatile, toxic chemical used to manufacture carbamate pesticides. In light of the December 1984 Bhopal, India disaster and possible safety problems at the Institute facility, NIOSH conducted this research as a basis upon which to recommend protective equipment that might be used in an emergency situation where extremely high MIC concentrations might be encountered. Both protective clothing and respirators were evaluated. In particular, NIOSH studies air-purifying respirators in order to assess their effectiveness against MIC vapor penetration. NIOSH does not recommend any air purifying respirator for MIC because of its high toxicity and lack of warming properties and because no effective end of service life indicator currently is available for MIC. This report addresses only MIC penetration through air-purifying cartridges at challenge concentration designed to simulate emergency escape conditions. The results presented are for two different manufacturers' organic vapor (OV) and acid gas cartridges. Penetration tests were conducted at three or four MIC challenge concentrations and at three different humidity conditions. In general, breakthrough times (1% of challenge concentration) were very short (<20 min). Also, high relative humidity was found to decrease the breakthrough time of MIC.

  3. Penetration of methyl isocyanate through organic vapor and acid gas respirator cartridges.

    PubMed

    Moyer, E S; Berardinelli, S P

    1987-04-01

    Methyl isocyanate (MIC) is a volatile, toxic chemical [Threshold Limit Value (TLV) = 0.02 ppm] used to manufacture carbamate pesticides. The principal manufacturer of MIC is Union Carbide, and the site of production is Institute, West Virginia. In light of the December 1984 Bhopal, India disaster and possible safety problems at the Institute facility, NIOSH conducted this research as a basis upon which to recommend protective equipment that might be used in an emergency situation where extremely high MIC concentrations might be encountered. Both protective clothing and respirators were evaluated. In particular, NIOSH studied air-purifying respirators in order to assess their effectiveness against MIC vapor penetration. NIOSH does not recommend any air purifying respirator for MIC because of its high toxicity and lack of warning properties and because no effective end of service life indicator currently is available for MIC. This report addresses only MIC penetration through air-purifying cartridges at challenge concentrations designed to simulate emergency escape conditions. Another report addresses the protective clothing issue. The results presented are for two different manufacturers' organic vapor (OV) and acid gas cartridges. Penetration tests were conducted at three or four MIC challenge concentrations and at three different humidity conditions. In general, breakthrough times (1% of challenge concentration) were very short (less than 20 min). Also, high relative humidity was found to decrease the breakthrough time of MIC. PMID:3591646

  4. Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Yan, Qiuhe; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-02-01

    Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.

  5. Reactions of charged phenyl radicals with aliphatic amino acids in the gas phase.

    PubMed

    Huang, Yiqun; Guler, Leo; Heidbrink, Jenny; Kenttämaa, Hilkka

    2005-03-23

    Gas-phase reactivity of five differently substituted positively charged phenyl radicals was examined toward six amino acids by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR). The reactivity of the radicals studied was determined by the electrophilicity of the radical, which can be characterized by the radical's electron affinity (EA). The larger the electron affinity of the radical, the higher the overall reaction rate. In addition to the expected H-atom abstraction, several unprecedented reaction pathways were observed, including NH2 abstraction, SH abstraction, and SCH3 abstraction. These reaction pathways dominate for the most electrophilic radicals, and they may not follow radical but rather nucleophilic addition-elimination mechanisms. Hydrogen abstraction from glycine was also investigated theoretically. The results indicate that hydrogen abstraction from alphaC of glycine is both kinetically and thermodynamically favored over the NH2 group. The ordering of transition state energies for hydrogen abstraction from the alphaC and NH2 groups was found to reflect the radicals' EA ordering.

  6. Chemical and physical properties of dry flue gas desulfurization products.

    PubMed

    Kost, David A; Bigham, Jerry M; Stehouwer, Richard C; Beeghly, Joel H; Fowler, Randy; Traina, Samuel J; Wolfe, William E; Dick, Warren A

    2005-01-01

    Beneficial and environmentally safe recycling of flue gas desulfurization (FGD) products requires detailed knowledge of their chemical and physical properties. We analyzed 59 dry FGD samples collected from 13 locations representing four major FGD scrubbing technologies. The chemistry of all samples was dominated by Ca, S, Al, Fe, and Si and strong preferential partitioning into the acid insoluble residue (i.e., coal ash residue) was observed for Al, Ba, Be, Cr, Fe, Li, K, Pb, Si, and V. Sulfur, Ca, and Mg occurred primarily in water- or acid-soluble forms associated with the sorbents or scrubber reaction products. Deionized water leachates (American Society for Testing and Materials [ASTM] method) and dilute acetic acid leachates (toxicity characteristic leaching procedure [TCLP] method) had mean pH values of >11.2 and high mean concentrations of S primarily as SO(2-)4 and Ca. Concentrations of Ag, As, Ba, Cd, Cr, Hg, Pb, and Se (except for ASTM Se in two samples) were below drinking water standards in both ASTM and TCLP leachates. Total toxicity equivalents (TEQ) of dioxins, for two FGD products used for mine reclamation, were 0.48 and 0.53 ng kg(-1). This was similar to the background level of the mine spoil (0.57 ng kg(-1)). The FGD materials were mostly uniform in particle size. Specific surface area (m2 g(-1)) was related to particle size and varied from 1.3 for bed ash to 9.5 for spray dryer material. Many of the chemical and physical properties of these FGD samples were associated with the quality of the coal rather than the combustion and SO2 scrubbing processes used.

  7. Determination of the optimum conditions for boric acid extraction with carbon dioxide gas in aqueous media from colemanite containing arsenic

    SciTech Connect

    Ata, O.N.; Colak, S.; Copur, M.; Celik, C.

    2000-02-01

    The Taguchi method was used to determine optimum conditions for the boric acid extraction from colemanite ore containing As in aqueous media saturated by CO{sub 2} gas. After the parameters were determined to be efficient on the extraction efficiency, the experimental series with two steps were carried out. The chosen experimental parameters for the first series of experiments and their ranges were as follows: (1) reaction temperature, 25--70 C; (2) solid-to-liquid ratio (by weight), 0.091 to 0.333; (3) gas flow rate (in mL/min), 66.70--711; (4) mean particle size, {minus}100 to {minus}10 mesh; (5) stirring speed, 200--600 rpm; (6) reaction time, 10--90 min. The optimum conditions were found to be as follows: reaction temperature, 70 C; solid-to-liquid ratio, 0.091; gas flow rate, 711 (in mL/min); particle size, {minus}100 mesh; stirring speed, 500 rpm; reaction time, 90 min. Under these optimum conditions, the boric acid extraction efficiency from the colemanite containing As was approximately 54%. Chosen experimental parameters for the second series of experiments and their ranges were as follows: (1) reaction temperature, 60--80 C; (2) solid-to-liquid ratio (by weight), 0.1000 to 0.167; (3) gas pressure (in atm), 1.5; 2.7; (4) reaction time, 45--120 min. The optimum conditions were found to be as follows: reaction temperature, 70 C; solid-to-liquid ratio, 0.1; gas pressure, 2.7 atm; reaction time, 120 min. Under these optimum conditions the boric acid extraction efficiency from the colemanite ore was approximately 75%. Under these optimum conditions, the boric acid extraction efficiency from calcined colemanite ore was approximately 99.55%.

  8. A Case-Control Study of Risk Factors Associated with Scrub Typhus Infection in Beijing, China

    PubMed Central

    Zhang, Liqin; Dou, Xiangfeng; Wang, Xiaomei; Li, Weihong; Zhang, Xiuchun; Sun, Yulan; Guan, Zengzhi; Li, Xinyu; Wang, Quanyi

    2013-01-01

    To investigate the risk factors of scrub typhus infection in Beijing, China, a case-control study was carried out. Cases (n = 56) were defined as persons who were diagnosed by PCR and serological method within three years. Three neighborhood control subjects were selected by matching for age and occupation. Living at the edge of the village, living in the houses near grassland, vegetable field or ditch, house yard without cement floor, piling weeds in the house or yard, all of these were risk factors for scrub typhus infection. Working in vegetable fields and hilly areas, and harvesting in autumn posed the highest risks, with odds ratios (ORs) and 95% confidence intervals (CIs) of 3.7 (1.1–11.9), 8.2 (1.4–49.5), and 17.2 (5.1–57.9), respectively. These results would be useful for the establishment of a detail control strategy for scrub typhus infection in Beijing, China. PMID:23691083

  9. Jet Surface Interaction Scrubbing Noise from High Aspect-Ratio Rectangular Jets

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Bozak, Richard F.

    2015-01-01

    Concepts envisioned for the future of civil air transport consist of unconventional propulsion systems in the close proximity of the airframe. Distributed propulsion system with exhaust configurations that resemble a high aspect ratio rectangular jet are among geometries of interest. Nearby solid surfaces could provide noise shielding for the purpose of reduced community noise. Interaction of high-speed jet exhaust with structure could also generate new sources of sound as a result of flow scrubbing past the structure, and or scattered noise from sharp edges. The present study provides a theoretical framework to predict the scrubbing noise component from a high aspect ratio rectangular exhaust in proximity of a solid surface. The analysis uses the Greens function (GF) to the variable density Pridmore-Brown equation in a transversely sheared mean flow. Sources of sound are defined as the auto-covariance function of second-rank velocity fluctuations in the jet plume, and are modeled using a RANS-based acoustic analogy approach. Acoustic predictions are presented in an 8:1 aspect ratio rectangular exhaust at three subsonic Mach numbers. The effect of nearby surface on the scrubbing noise component is shown on both reflected and shielded sides of the plate.

  10. Use of hydrogen peroxide in scrubbing towers for odor removal in wastewater treatment plants.

    PubMed

    Charron, I; Féliers, C; Couvert, A; Laplanche, A; Patria, L; Requieme, B

    2004-01-01

    The aim of this work was to replace sodium hypochlorite (NaCIO) with hydrogen peroxide (H202) in chemical scrubbing towers, in order to avoid the formation of chlorinated species, harmful for human health. Some previous studies have already shown the ability of H2O2 to treat the hydrogen sulfide (H2S) pollution. However, an important decomposition of the oxidant was observed in the scrubbing solution (carbonates, transition metal and high pH are responsible for this decomposition) leading to high reactant consumption. Consequently, this study first focused on research into a compound able to reduce the hydrogen peroxide degradation. Experiments were conducted on a pilot unit (3,000 m3 h(-1)) in a wastewater treatment plant. The sodium silicate (Na2SiO3) proved to be a good scrubbing solution stabilizer. A very good removal of hydrogen sulfide (up to 98%) was also obtained. Finally, the study resulted in the determination of the best operating conditions to achieve both an efficient and economical process.

  11. Efficacy of a surgical scrub including 2% chlorhexidine acetate for canine superficial pyoderma.

    PubMed

    Murayama, Nobuo; Nagata, Masahiko; Terada, Yuri; Shibata, Sanae; Fukata, Tsuneo

    2010-12-01

    The clinical efficacy of a surgical scrub containing 2% chlorhexidine acetate (2CA; Nolvasan® Surgical Scrub; Fort Dodge Animal Health, USA) was evaluated for the topical management of canine superficial pyoderma. The first study was a randomized, double-blind, controlled trial. The control was a shampoo containing 4% chlorhexidine gluconate (4CG; Skin Clinic Shampoo; CHD MEDICS, Goyang, Korea). Ten dogs with symmetrical lesions of canine superficial pyoderma were allocated to receive either 2CA or the control shampoo applied to either side of the body twice weekly for 1 week. Both the owners and the investigators subjectively scored skin lesions including pruritus, erythema, crusted papules and scales on a scale of 0-3. The 2CA and 4CG resulted in almost the same degree of improvement of skin lesions, and there were no significant differences between the two groups. The second study was an open trial of 2CA monotherapy in eight dogs with cefalexin-resistant Staphylococcus intermedius group-associated superficial pyoderma. The 2CA monotherapy was applied every 2 days for 2 weeks. Five dogs improved with 2CA monotherapy, one partially improved and two did not. No adverse reactions were seen in either trial. This suggests that a 2CA surgical scrub could be a useful and safe topical adjunct therapy for dogs with superficial pyoderma involving cefalexin-resistant Staphylococcus intermedius group.

  12. Laboratory Diagnosis and Genotype Identification of Scrub Typhus from Pinggu District, Beijing, 2008 and 2010

    PubMed Central

    Li, Weihong; Dou, Xiangfeng; Zhang, Liqin; Lyu, Yanning; Du, Zhizhong; Tian, Lili; Zhang, Xiuchun; Sun, Yulan; Guan, Zengzhi; Chen, Lijuan; Li, Xinyu; Wang, Quanyi

    2013-01-01

    This study was conducted to determine the diagnosis and genotype of Orientia tsutsugamushi in Pinggu district, Beijing. Indirect immunofluorescence assay (IFA) was performed to detect O. tsutsugamushi-specific immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies. Nested polymerase chain reaction (PCR) and DNA sequencing analysis targeting the O. tsutsugamushi-specific groEL gene and 56 kDa protein gene were performed on whole-blood samples from scrub typhus patients. We confirmed that 47 patients were infected with scrub typhus in Pinggu district, Beijing. Representative sequences amplified by primers according to the groEL gene (BJ-PG-2008; GenBank accession No. JQ894502) and the 56 kDa protein gene (PG-56kDa; GenBank accession No. JX843795) both clustered with Kawasaki. PG-56kDa had sequence homology of 100% with TADY12-0308, shandong-XDM2, Neimeng-90, and sdu-1 and sequence homology of 96% with Kawasaki, Taguchi, Oishi, and Kanda. We confirmed the genotype of O. tsutsugamushi in Pinggu district, Beijing, as Kawasaki, and the patient in 2008 confirmed in this study was the first patient with confirmed scrub typhus in Beijing. PMID:23716411

  13. Nitrogen deposition effects on carbon storage and fungal:bacterial ratios in coastal sage scrub soils of southern California.

    PubMed

    Liu, Kun; Crowley, David

    2009-01-01

    The effects of nitrogen (N) across a deposition gradient on bacterial and fungal degradation pathways were studied in southern California coastal sage scrub soils to determine whether elevated N levels alter microbial community structure and organic matter accumulation. Three sites across an N deposition gradient having low, intermediate, and high levels of atmospheric N deposition were studied for 20 mo. Fungi:bacteria (F:B) biomass ratios were determined by phospholipid fatty acid analysis. Plots at each location included control plots receiving ambient N deposition and treatment plots that were fertilized with an additional 50 kg N ha(-1) yr(-1) of slow-release urea. Results showed that organic carbon (C) levels varied seasonally but that F:B ratios were relatively stable and similar across the three locations and over time. Total organic C decreased in response to N additions only at the low N deposition site. The results suggest that organic matter degradation pathways leading to C storage in soils that have been exposed to high levels of atmospheric N deposition are not responsive to additional increases in N and that N effects on organic C in semiarid soils may be significant only in areas with prior low exposure to N pollution.

  14. Testing to reduce salt loading via wet scrubbing

    SciTech Connect

    Holmes, H.; Burns, D.B.

    1990-01-01

    Previous offgas testing indicated that excessive salt emissions generated by neutralization of acids minimize filter life of downstream control equipment, specifically, high efficient particulate air (HEPA) filters. Recent tests were conducted to characterize salt generation in wet offgas systems and to evaluate upstream offgas control equipment performance in removing the salt. The predominant conclusion was that stack salt particulate emissions responsible for rapid loading of the offgas filters resulted from carry-over of particulates formed in the scrubber, and not carry-over from those formed in the quench. HEPA filter loading tests showed no significant filter pluggage at low salt concentrations in the scrubber liquid in spite of high salt concentrations in the quench liquid. 10 figs., 2 tabs.

  15. Gas chromatographic separation of fatty acid esters of cholesterol and phytosterols on an ionic liquid capillary column.

    PubMed

    Hammann, Simon; Vetter, Walter

    2015-12-15

    Steryl esters are high molecular weight compounds (600-700g/mol) regularly present as a minor lipid class in animal and plant lipids. Different sterol backbones (e.g., cholesterol, β-sitosterol and brassicasterol) which can be esterified with various fatty acids can result in highly complex steryl ester patterns in food samples. The gas chromatographic (GC) analysis of intact steryl esters is challenging, since high elution temperatures are required for their elution. On nonpolar GC phases, steryl esters with fatty acids with differing degree of unsaturation (e.g., oleate and linoleate) cannot be separated and there are only few polar columns available with sufficient temperature stability. In this study, we used gas chromatography with mass spectrometry (GC/MS) and analyzed intact steryl esters on a commercial room temperature ionic liquid (RTIL) column which was shortened to a length of 12m. The column separated the steryl esters both by total carbon number and by degree of unsaturation of the fatty acid. For instance, cholesteryl esters with stearic acid (18:0), oleic acid (18:1n-9), linoleic acid (18:2n-6) and α-linolenic acid (18:3n-3) could be resolved (R≥1.3) from each other. By analysis of synthesized standard substances, the elution orders for different steryl backbones and different fatty acids on a given sterol backbone could be determined. Analysis of spreads and plant oils allowed to determine retention times for 37 steryl esters, although a few co-elutions were observed. The ionic liquid column proved to be well-suited for the analysis of intact steryl esters.

  16. Electrochemical Reduction of CO2 to Organic Acids by a Pd-MWNTs Gas-Diffusion Electrode in Aqueous Medium

    PubMed Central

    Lu, Guang; Bian, Zhaoyong; Liu, Xin

    2013-01-01

    Pd-multiwalled carbon nanotubes (Pd-MWNTs) catalysts for the conversion of CO2 to organic acids were prepared by the ethylene glycol reduction and fully characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) technologies. The amorphous Pd particles with an average size of 5.7 nm were highly dispersed on the surface of carbon nanotubes. Functional groups of the MWNTs played a key role in the palladium deposition. The results indicated that Pd-MWNTs could transform CO2 into organic acid with high catalytic activity and CO2 could take part in the reduction reaction directly. Additionally, the electrochemical reduction of CO2 was investigated by a diaphragm electrolysis device, using a Pd-MWNTs gas-diffusion electrode as a cathode and a Ti/RuO2 net as an anode. The main products in present system were formic acid and acetic acid identified by ion chromatograph. The selectivity of the products could be achieved by reaction conditions changing. The optimum faraday efficiencies of formic and acetic acids formed on the Pd-MWNTs gas-diffusion electrode at 4 V electrode voltages under 1 atm CO2 were 34.5% and 52.3%, respectively. PMID:24453849

  17. Scrub-successional bird community dynamics in young and mature longleaf pine-wiregrass savannahs

    USGS Publications Warehouse

    Krementz, D.G.; Christie, J.S.

    1999-01-01

    Public agencies are required to manage for threatened and endangered species and for biodiversity. However, at times, management for threatened and endangered species precludes consideration of other species. We investigated how managing for red-cockaded woodpeckers (Picoides borealis) and biodiversity at the Savannah River Site (SRS), South Carolina, affected communities of bird species that use early-successional scrub habitat (hereafter, scrub-successional species). Management for red-cockaded woodpeckers at the SRS involved both (1) manipulating mature longleaf pine (Pinus palustris)-wiregrass (Andropogon spp.) stands via canopy thinning, removal of midstory trees, and prescribed burning; and (2) even-aged timber harvesting. The former management practice encouraged red-cockaded woodpeckers to establish new colonies in previously unoccupied stands (hereafter, 'recruitment' stands). The latter management practice is used to remove off-site planted pines and replant with preferred longleaf pines. We conducted a constant-effort mist net study in recruitment and regenerating stands (stands clearcut and planted with longleaf pine) during the breeding seasons of 1995-96. We hypothesized that the scrub-successional bird community in recruitment stands would have greater species richness and higher survival and reproductive rates per species than in regenerating stands. However, recruitment stands always had fewer scrub-successional species (1995:36 species; 1996:31 species) than regenerating stands (1995:54 species; 1996:55 species), and all species that occurred in recruitment stands also occurred in regenerating stands. Species which commonly occurred in both recruitment and regenerating stands had similar adult:juvenile ratios (P > 0.15) and relative proportion of adults in breeding condition (P > 0.05). We detected no difference in survival rates of Bachman's sparrows (Aimophila aestivalis), indigo buntings (Passerina cyanea), and of 'combined' scrub

  18. Anatomy of an upgraded pulverized coal facility: Combustion modification through flue gas scrubbing

    SciTech Connect

    Watts, J.U.; Savichky, W.J.; O`Dea, D.T.

    1997-12-31

    Regeneration is a biological term for formation or creating anew. In the case of Milliken station, a species of steam generation (Tangentus coali) regeneration refers to refitting critical systems with the latest technological advances to reduce emissions while maintaining or improving performance. The plant has undergone a series of operations which provided anatomical changes as well as a face lift. Each of the two units were place in suspended animation (outage) to allow these changes to be made. The paper describes the project which includes retrofitting combustion systems, pulverizers, boiler liners, scrubbers, and control room. This retrofit is meant to increase thermal efficiency while reducing the formation of nitrogen oxides.

  19. Characterization of benthic microbial community structure by high-resolution gas chromatography of fatty acid methyl esters

    SciTech Connect

    Bobbie, R.J.; White, D.C.

    1980-06-01

    Fatty acids are a widely studied group of lipids of sufficient taxonomic diversity to be useful in defining microbial community structure. The gas-liquid chromatographic analyses are both reproducible and highly sensitive, and the recovery of fatty acids is quantitative. The analyses can be automated, and the diagnostic technique of mass spectral fragmentation analysis can be readily applied. Reciprocal mixtures of bacteria and fungi, when extracted and analyzed, showed progressive changes of distinctive fatty acid methyl esters derived from the lipids. By manipulating the environment of an estuarine detrital microbial community with antibiotics and culture conditions, it was possible to produce a community greatly enriched in eucaryotic fungi, as evidenced by scanning electron microscopic morphology. The fatty acid methyl C/sub 18/ dienoic and the C/sub 18/ and C/sub 20/ polyenoic esters. Manipulation of the detrital microbiota that increased the procaryotic population resulted in an absence of large structures typical of fungal mycelia or diatoms, as evidenced by scanning electron microscopy, and a significantly larger proportion of anteiso and isobranched C/sub 15/ fatty acid esters, C/sub 17/ cyclopropane fatty acid esters, and the cisvaccenic isomer of the C/sub 18/ monoenoic fatty acid esters. As determined by these techniques, a marine settling community showed greater differences in bacterial as contrasted to microeucaryotic populations when compared with the microbial communities of benthic cores.

  20. Gas chromatographic separation of stereoisomers of non-protein amino acids on modified γ-cyclodextrin stationary phase.

    PubMed

    Fox, Stefan; Strasdeit, Henry; Haasmann, Stephan; Brückner, Hans

    2015-09-11

    Stereoisomers (enantiomers and diastereoisomers) of synthetic, non-protein amino acids comprising α-, β-, and γ-amino acids, including α,α-dialkyl amino acids, were converted into the respective N-trifluoroacetyl-O-methyl esters and analyzed and resolved by gas chromatography (GC) on a commercial fused silica capillary column coated with the chiral stationary phase octakis(3-O-butyryl-2,6-di-O-pentyl)-γ-cyclodextrin. This column is marketed under the trade name Lipodex(®) E. Chromatograms, retention times, and a chart displaying the retention times of approximately 40 stereoisomers of amino acids are presented. With few exceptions, baseline or almost baseline resolution was achieved for enantiomers and diastereoisomers. The chromatographic method presented is considered to be highly suitable for the elucidation of the stereochemistry of non-protein amino acids, for example in natural products, and for evaluating the enantiopurity of genetically non-coded amino acids used for the synthesis and design of conformationally tailored peptides. The method is applicable to extraterrestrial materials or can be used in experimental work related to abiotic syntheses or enantioselective destruction and amplification of amino acids. PMID:26278360

  1. Simultaneous determination of sorbic and benzoic acids in food dressing by headspace solid-phase microextraction and gas chromatography.

    PubMed

    Dong, Chunzhou; Mei, Yong; Chen, Lin

    2006-06-01

    A facile headspace solid-phase microextraction (HS-SPME) procedure using 85 microm polyacrylate (PA) fiber is presented for the simultaneous determination of preservatives (sorbic and benzoic acids) in food dressing, including Thousand Island Dressing, HellMANN'S Salad Dressing and Tomato Ketchup, by gas chromatography (GC) with flame ionization detector (FID). The method presented preserves the advantages typical of HS-SPME such as simplicity, low intensity of labor, low cost and solvent free. The main factors affecting the HS-SPME process, such as extraction temperature and time, desorption temperature and time, the acidity and salt concentration of the solution, were optimized. Limits of detection (LODs) of the method were 2.00 microg/L for sorbic acid and 1.22 microg/L for benzoic acid. Relative standard deviations (RSDs) for quintuplicate analyses at three concentration levels of 0.10, 2.0 and 20 mg/L ranged between 3.86 and 14.8%. The method also showed good linearity n a range from 0.02 to 40 mg/L with correlation coefficients (R2) of 0.9986 for sorbic acid and 0.9994 for benzoic acid. Recoveries for the two analytes in all the samples tested ranged from 83.44 to 113.2%. Practical applicability was demonstrated through the simultaneous determination of sorbic and benzoic acids in the three complex samples. PMID:16650850

  2. Gas chromatographic separation of stereoisomers of non-protein amino acids on modified γ-cyclodextrin stationary phase.

    PubMed

    Fox, Stefan; Strasdeit, Henry; Haasmann, Stephan; Brückner, Hans

    2015-09-11

    Stereoisomers (enantiomers and diastereoisomers) of synthetic, non-protein amino acids comprising α-, β-, and γ-amino acids, including α,α-dialkyl amino acids, were converted into the respective N-trifluoroacetyl-O-methyl esters and analyzed and resolved by gas chromatography (GC) on a commercial fused silica capillary column coated with the chiral stationary phase octakis(3-O-butyryl-2,6-di-O-pentyl)-γ-cyclodextrin. This column is marketed under the trade name Lipodex(®) E. Chromatograms, retention times, and a chart displaying the retention times of approximately 40 stereoisomers of amino acids are presented. With few exceptions, baseline or almost baseline resolution was achieved for enantiomers and diastereoisomers. The chromatographic method presented is considered to be highly suitable for the elucidation of the stereochemistry of non-protein amino acids, for example in natural products, and for evaluating the enantiopurity of genetically non-coded amino acids used for the synthesis and design of conformationally tailored peptides. The method is applicable to extraterrestrial materials or can be used in experimental work related to abiotic syntheses or enantioselective destruction and amplification of amino acids.

  3. Determination of glutamic acid and gamma-aminobutyric acid in Ringer's solution without desalination at the femtomole level by gas chromatography chemical ionization mass spectrometry.

    PubMed

    Murayama, K; Shindo, N; Mineki, R; Ohta, K

    1981-04-01

    For the quantification of glutamic acid in Ringer's solution, pentafluoropropionic methyl ester was the most sensitive derivative. The detectable concentration was 0.01 microM glutamic acid in Ringer's solution; the amount of the preparation was 1 pmol and the injection into a gas chromatograph mass spectrometer was 10 fmol. For the quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was quantification of gamma-aminobutyric acid in Ringer's solution, the trifluoroacetal-hexafluoropropionyl ester was detectable at a concentration of 0.01 microM. Ringer's salts facilitated acylation in the order heptafluorobutyric anhydride greater than pentafluoropropionic anhydride greater than trifluoroacetic anhydride. The effect depended on esterification of carboxy groups in the order methyl ester greater than hexafluoropropionyl ester greater than butyl ester. Sodium carbonate, sodium acetate and sodium citrate also facilitated acylation with pentafluoroproionic anhydride, while sodium phosphate inhibited the acylation and sodium sulfate inhibited it slightly. The pentafluoropropionic methyl ester of glutamic acid was stable for up to 10 days, when it was dissolved in acetone and stored at -18 degrees C.

  4. Interactions of Gas-Phase Nitric/Nitrous Acids and Primary Organic Aerosol in the Atmosphere of Houston, TX

    NASA Astrophysics Data System (ADS)

    Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Whitlow, S. I.; Lefer, B. L.; Flynn, J.; Rappenglück, B.

    2007-12-01

    Concentrations of aerosol and gas-phase pollutants were measured on the roof of an 18-story building during the Texas Air Quality Study II Radical and Aerosol Measurement Project (TRAMP) from August 15 through September 28, 2006. Aerosol measurements included size-resolved, non-refractory mass concentrations of ammonium, nitrate, sulfate, chloride, and organic aerosol in submicron particles using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS). Particulate water-soluble organic carbon (PWSOC) was quantified using a mist chamber/total organic carbon analysis system. Concentration data for gas-phase pollutants included those for nitric acid (HNO3), nitrous acid (HONO), and hydrochloric acid (HCl) collected using a mist chamber/ion chromatographic technique, oxides of nitrogen (NOx) collected using a chemiluminescent method, and carbon monoxide (CO) collected using an infrared gas correlation wheel instrument. Coincident increases in nitrate and organic aerosol mass concentrations were observed on many occasions throughout the measurement campaign, most frequently during the morning rush hour. Based on the lack of organic aerosol processing (defined by the ratio of m/z = 44/57 in the Q-AMS spectra), strong correlation with NOx and CO, and a lack of significant increase in PWSOC concentration, the spikes in organic aerosol were likely associated with primary organic aerosol (POA). During these events, gas-phase HNO3 concentration decreases were observed simultaneously with increases in gas-phase HONO concentrations. These data likely indicate uptake of HNO3 and subsequent heterogeneous conversion to HONO involving POA. Preliminary calculations show that HNO3 partitioning could account for the majority of the observed HONO and aerosol nitrate concentrations during these events. Q-AMS chloride and HCl data also indicate uptake of chloride by particles during these events. This phenomenon was also observed during the night, but these nocturnal events were less

  5. Advanced separation technology for flue gas cleanup. Revised quarterly technical report No. 17, April--June 1996

    SciTech Connect

    Bhown, A.S.; Riggs, T.; Bahman, A.

    1996-10-01

    The objective of this work is to develop a novel system for regenerable SO{sub 2} and NO{sub x} scrubbing of flue gas that focuses on (a) a novel method for regeneration of spent SO{sub 2} scrubbing liquor and (b) novel chemistry for reversible absorption of NO{sub x}. In addition, high efficiency hollow fiber contactors, (HFC) are proposed as the devices for scrubbing the SO{sub 2} and NO{sub x} from the flue gas. The system will be designed to remove more than 95% of the SO{sub x} and more than 75% of the NO{sub x} from flue gases typical of pulverized coal-fired power plants at a cost that is at least 20% less than combined wet limestone scrubbing of SO{sub x} and selective catalytic reduction of NO{sub x}. In addition, the process will make only marketable byproducts, if any (no waste streams).

  6. Evaporation of iodine-containing off-gas scrubber solution

    DOEpatents

    Partridge, J.A.; Bosuego, G.P.

    1980-07-14

    Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

  7. Gas-phase ion/ion reactions of peptides and proteins: acid/base, redox, and covalent chemistries.

    PubMed

    Prentice, Boone M; McLuckey, Scott A

    2013-02-01

    Gas-phase ion/ion reactions are emerging as useful and flexible means for the manipulation and characterization of peptide and protein biopolymers. Acid/base-like chemical reactions (i.e., proton transfer reactions) and reduction/oxidation (redox) reactions (i.e., electron transfer reactions) represent relatively mature classes of gas-phase chemical reactions. Even so, especially in regards to redox chemistry, the widespread utility of these two types of chemistries is undergoing rapid growth and development. Additionally, a relatively new class of gas-phase ion/ion transformations is emerging which involves the selective formation of functional-group-specific covalent bonds. This feature details our current work and perspective on the developments and current capabilities of these three areas of ion/ion chemistry with an eye towards possible future directions of the field.

  8. Per-fluorinated sulfonic acid/PTFE copolymer studied by positron annihilation lifetime and gas permeation techniques

    NASA Astrophysics Data System (ADS)

    Mohamed, Hamdy F. M.; Abdel-Hady, E. E.; Ohira, A.

    2015-06-01

    The mechanism of gas permeation in per-fluorinated sulfonic acid/PTFE copolymer Fumapem® membranes for polymer electrolyte fuel cells has been investigated from the viewpoint of free volume. Three different samples, Fumapem® F-950, F-1050 and F-14100 membranes with ion exchange capacity (IEC) = 1.05, 0.95 and 0.71 meq/g, respectively were used after drying. Free volume was quantified using the positron annihilation lifetime (PAL) technique and gas permeabilities were measured for O2 and H2 as function of temperature. Good linear correlation between the logarithm of the permeabilities at different temperatures and reciprocal free volume indicate that gas permeation in dry Fumapem® is governed by the free volume. Nevertheless permeabilities are much smaller than the corresponding flexible chain polymer with a similar free volume size due to stiff chains of the perfluoroethylene backbone.

  9. Fluoro- and perfluoralkylsulfonylpentafluoroanilides: synthesis and characterization of NH acids for weakly coordinating anions and their gas-phase and solution acidities.

    PubMed

    Kögel, Julius F; Linder, Thomas; Schröder, Fabian G; Sundermeyer, Jörg; Goll, Sascha K; Himmel, Daniel; Krossing, Ingo; Kütt, Karl; Saame, Jaan; Leito, Ivo

    2015-04-01

    Fluoro- and perfluoralkylsulfonyl pentafluoroanilides [HN(C6F5)(SO2X); X = F, CF3, C4F9, C8F17] are a class of imides with two different strongly electron-withdrawing substituents attached to a nitrogen atom. They are NH acids, the unsymmetrical hybrids of the well-known symmetrical bissulfonylimides and bispentafluorophenylamine. The syntheses, the structures of these perfluoroanilides, their solvates, and some selected lithium salts give rise to a structural variety beyond the symmetrical parent compounds. The acidities of representative subsets of these novel NH acids have been investigated experimentally and quantum-chemically and their gas-phase acidities (GAs) are reported, as well as the pKa values of these compounds in acetonitrile (MeCN) and DMSO solution. In quantum chemical investigations with the vertical and relaxed COSMO cluster-continuum models (vCCC/rCCC), the unusual situation is encountered that the DMSO-solvated acid Me2SO-H-N(SO2CF3)2, optimized in the gas phase (vCCC model), dissociates to Me2SO-H(+)-N(SO2CF3)2(-) during structural relaxation and full optimization with the solvation model turned on (rCCC model). This proton transfer underlines the extremely high acidity of HN(SO2CF3)2. The importance of this effect is studied computationally in DMSO and MeCN solution. Usually this effect is less pronounced in MeCN and is of higher importance in the more basic solvent DMSO. Nevertheless, the neglect of the structural relaxation upon solvation causes typical changes in the computational pKa values of 1 to 4 orders of magnitude (4-20 kJ mol(-1)). The results provide evidence that the published experimental DMSO pKa value of HN(SO2CF3)2 should rather be interpreted as the pKa of a Me2SO-H(+)-N(SO2CF3)2(-) contact ion pair. PMID:25727401

  10. Fluoro- and perfluoralkylsulfonylpentafluoroanilides: synthesis and characterization of NH acids for weakly coordinating anions and their gas-phase and solution acidities.

    PubMed

    Kögel, Julius F; Linder, Thomas; Schröder, Fabian G; Sundermeyer, Jörg; Goll, Sascha K; Himmel, Daniel; Krossing, Ingo; Kütt, Karl; Saame, Jaan; Leito, Ivo

    2015-04-01

    Fluoro- and perfluoralkylsulfonyl pentafluoroanilides [HN(C6F5)(SO2X); X = F, CF3, C4F9, C8F17] are a class of imides with two different strongly electron-withdrawing substituents attached to a nitrogen atom. They are NH acids, the unsymmetrical hybrids of the well-known symmetrical bissulfonylimides and bispentafluorophenylamine. The syntheses, the structures of these perfluoroanilides, their solvates, and some selected lithium salts give rise to a structural variety beyond the symmetrical parent compounds. The acidities of representative subsets of these novel NH acids have been investigated experimentally and quantum-chemically and their gas-phase acidities (GAs) are reported, as well as the pKa values of these compounds in acetonitrile (MeCN) and DMSO solution. In quantum chemical investigations with the vertical and relaxed COSMO cluster-continuum models (vCCC/rCCC), the unusual situation is encountered that the DMSO-solvated acid Me2SO-H-N(SO2CF3)2, optimized in the gas phase (vCCC model), dissociates to Me2SO-H(+)-N(SO2CF3)2(-) during structural relaxation and full optimization with the solvation model turned on (rCCC model). This proton transfer underlines the extremely high acidity of HN(SO2CF3)2. The importance of this effect is studied computationally in DMSO and MeCN solution. Usually this effect is less pronounced in MeCN and is of higher importance in the more basic solvent DMSO. Nevertheless, the neglect of the structural relaxation upon solvation causes typical changes in the computational pKa values of 1 to 4 orders of magnitude (4-20 kJ mol(-1)). The results provide evidence that the published experimental DMSO pKa value of HN(SO2CF3)2 should rather be interpreted as the pKa of a Me2SO-H(+)-N(SO2CF3)2(-) contact ion pair.

  11. In situ derivatization and hollow fiber membrane microextraction for gas chromatographic determination of haloacetic acids in water.

    PubMed

    Varanusupakul, Pakorn; Vora-Adisak, Narongchai; Pulpoka, Bancha

    2007-08-13

    An alternative method for gas chromatographic determination of haloacetic acids (HAAs) in water using direct derivatization followed by hollow fiber membrane liquid-phase microextraction (HF-LPME) has been developed. The method has improved the sample preparation step according to the conventional US EPA Method 552.2 by combining the derivatization and the extraction into one step prior to determination by gas chromatography electron captured detector (GC-ECD). The HAAs were derivatized with acidic methanol into their methyl esters and simultaneously extracted with supported liquid hollow fiber membrane in headspace mode. The derivatization was attempted directly in water sample without sample evaporation. The HF-LPME was performed using 1-octanol as the extracting solvent at 55 degrees C for 60 min with 20% Na2SO4. The linear calibration curves were observed for the concentrations ranging from 1 to 300 microg L(-1) with the correlation coefficients (R2) being greater than 0.99. The method detection limits of most analytes were below 1 microg L(-1) except DCAA and MCAA that were 2 and 18 microg L(-1), respectively. The recoveries from spiked concentration ranged from 97 to 109% with %R.S.D. less than 12%. The method was applied for determination of HAAs in drinking water and tap water samples. The method offers an easy one step high sample throughput sample preparation for gas chromatographic determination of haloacetic acids as well as other contaminants in water. PMID:17693310

  12. Decomposition of organochlorine compounds in flue gas from municipal solid waste incinerators using natural and activated acid clays.

    PubMed

    Hwang, In-Hee; Takahashi, Shigetoshi; Matsuo, Takayuki; Matsuto, Toshihiko

    2014-09-01

    High-temperature particle control (HTPC) using a ceramic filter is a dust collection method without inefficient cooling and reheating of flue gas treatment; thus, its use is expected to improve the energy recovery efficiency of municipal solid waste incinerators (MSWIs). However there are concerns regarding de novo synthesis and a decrease in the adsorptive removal efficiency of dioxins (DXNs) at approximately 300 degrees C. In this study, the effect of natural and activated acid clays on the decomposition of monochlorobenzene (MCB), one of the organochlorine compounds in MSW flue gas, was investigated. From the results of MCB removal tests at 30-300 degrees C, the clays were classified as adsorption, decomposition, and low removal types. More than half of the clays (four kinds of natural acid clays and two kinds of activated acid clays) were of the decomposition type. In addition, the presence of Cl atoms detached from MCB was confirmed by washing the clay used in the MCB removal test at 300 degrees C. Activated acid clay was expected to have high dechlorination performance because of its proton-rich-composition, but only two clays were classed as decomposition type. Conversely, all the natural acid clays used in this work were of the decomposition type, which contained relatively higher di- and trivalent metal oxides such as Al2O3, Fe2O3, MgO, and CaO. These metal oxides might contribute to the catalytic dechlorination of MCB at 300 degrees C. Therefore, natural and activated acid clays can be used as alternatives for activated carbon at 300 degrees C to remove organochloride compounds such as DXNs. Their utilization is expected to mitigate the latent risks related to the adoption of HTPC, and also to contribute to the improvement of energy recovery efficiency of MSWI. Implications: The effect of natural and activated acid clays on MCB decomposition was investigated to evaluate their suitability as materials for the removal of organochlorine compounds, such as

  13. Electronic Effects of 11β Substituted 17β-Estradiol Derivatives and Instrumental Effects on the Relative Gas Phase Acidity

    NASA Astrophysics Data System (ADS)

    Bourgoin-Voillard, Sandrine; Fournier, Françoise; Afonso, Carlos; Zins, Emilie-Laure; Jacquot, Yves; Pèpe, Claude; Leclercq, Guy; Tabet, Jean-Claude

    2012-12-01

    Numerous studies have highlighted the role of the proton donor characteristics of the phenol group of 17β-estradiol (E2) in its association with the estrogen receptor alpha (ERα). Since the substitutions at position C(11) have been reported to modulate this association, we hypothesized that such substitutions may modify the phenol acidity. Hence, phenol gas-phase acidity of nine C(11)-substituted E2-derivatives were evaluated using the extended Cooks' kinetic method, which is a method widely used to determine thermochemical properties by mass spectrometry. To enhance accuracy in data collection we recorded data from several instruments, including quadrupole ion trap, triple quadrupole, and hybrid QqTOF. Indeed, we report for the first time the use of the QqTOF instrument to provide a novel means to improve data accuracy by giving access to an intermediate effective temperature range. All experimental gas-phase acidity values were supported by theoretical calculations. Our results confirmed the ability of distant substituents at C(11) to modulate the phenol acidity through electrostatic interactions, electron withdrawing inductive effects, and mesomeric effects. However, no relationship was found between the phenol gas-phase acidity of investigated steroids and their binding affinity for ERα assessed in solution. Thus, our results highlight that the intrinsic properties of the hormone do not influence sufficiently the stabilization of the hormone/ERα complex. It is more likely that such stabilization would be more related to factors depending on the environment within the binding pocket such as hydrophobic, steric as well as direct intermolecular electrostatic effects between ERα residues and the substituted steroidal estrogens.

  14. The effect of biotin on the production of succinic acid by Anaerobiospirillum succiniciproducens

    SciTech Connect

    Nghiem, N.P.; Davison, B.H.; Thompson, J.E.

    1995-07-01

    Succinic acid is an intermediate of the tricarboxylic acid (TCA) cycle, and therefore, is found in almost all plant and animal cells, albeit at very low concentrations. It has a very wide usage range, which includes applications in agriculture, food, medicine, plastics, cosmetics, textiles, plating and waste-gas scrubbing. Succinic acid currently is produced commercially by chemical processes. A fermentation process for its production is of great interest because in such process, renewable resources such as corn-derived glucose can be used as starting material. There is not a current biological process for the commercial production of succinic acid. Extensive efforts have been devoted to the isolation and screening of succinic acid-producing microorganisms. The anaerobic bacterium, Anaerobiospirillum succiniciproducens, is considered among the best direct succinic acid producers. A number of patents concerning the production of succinic acid by this organism have been issued. Our first attempt to develop a biological process for the production of succinic acid by A. succiniciproducens involved fermentation media improvement, in particular the use of supplemented nutrients. In this note, we show that higher yield of succinic acid could be achieved by supplementing the fermentation media with biotin, as a potential nutrient supplement representative.

  15. Effects of candidate gene polymorphisms on the detailed fatty acids profile determined by gas chromatography in bovine milk.

    PubMed

    Pegolo, S; Cecchinato, A; Mele, M; Conte, G; Schiavon, S; Bittante, G

    2016-06-01

    Association analyses between candidate genes and bovine milk fatty acids can improve our understanding of genetic variation in milk fatty acid profiles and reveal potential opportunities to tailor milk fat composition through selection strategies. In this work, we investigated the association of 51 single nucleotide polymorphisms (SNP) selected from 37 candidate genes using a functional and positional approach, with 47 fatty acids, 9 fatty acid groups, and 5 Δ(9)-desaturation indices in milk samples from Brown Swiss cows. Individual milk samples were collected from 1,158 Italian Brown Swiss cows, and gas chromatography was used to obtain detailed milk fatty acid compositions. A GoldenGate assay system (Illumina, San Diego, CA) was used to perform genotype 96 selected SNP located in 54 genes across 22 chromosomes. In total, 51 polymorphic SNP in 37 candidate genes were retained for the association analysis. A Bayesian linear animal model was used to estimate the contribution of each SNP. A total of 129 tests indicated relevant additive effects between a given SNP and a single fatty acid trait; 38 SNP belonging to 30 genes were relevant for a total of 57 fatty acid traits. Most of the studied fatty acid traits (~81%) were relevantly associated with multiple SNP. Relevantly associated SNP were mainly found in genes related to fat metabolism, linked to or contained in previously identified quantitative trait loci for fat yield or content, or associated with genes previously identified in association analyses with milk fatty acid profiles in other cow breeds. The most representative candidate genes were LEP, PRL, STAT5A, CCL3, ACACA, GHR, ADRB2, LPIN1, STAT1, FABP4, and CSN2. In particular, relevant associations with SNP located on bovine chromosome 19 (BTA19) were found. Two candidate genes on BTA19 (CCL3 and ACACA) were relevantly associated with de novo short- and medium-chain fatty acids, likely explaining the high heritability values found for these fatty acids

  16. Increased Nucleosomes and Neutrophil Activation Link to Disease Progression in Patients with Scrub Typhus but Not Murine Typhus in Laos.

    PubMed

    Paris, Daniel H; Stephan, Femke; Bulder, Ingrid; Wouters, Diana; van der Poll, Tom; Newton, Paul N; Day, Nicholas P J; Zeerleder, Sacha

    2015-01-01

    Cell-mediated immunity is essential in protection against rickettsial illnesses, but the role of neutrophils in these intracellular vasculotropic infections remains unclear. This study analyzed the plasma levels of nucleosomes, FSAP-activation (nucleosome-releasing factor), and neutrophil activation, as evidenced by neutrophil-elastase (ELA) complexes, in sympatric Lao patients with scrub typhus and murine typhus. In acute scrub typhus elevated nucleosome levels correlated with lower GCS scores, raised respiratory rate, jaundice and impaired liver function, whereas neutrophil activation correlated with fibrinolysis and high IL-8 plasma levels, a recently identified predictor of severe disease and mortality. Nucleosome and ELA complex levels were associated with a 4.8-fold and 4-fold increased risk of developing severe scrub typhus, beyond cut off values of 1,040 U/ml for nucleosomes and 275 U/ml for ELA complexes respectively. In murine typhus, nucleosome levels associated with pro-inflammatory cytokines and the duration of illness, while ELA complexes correlated strongly with inflammation markers, jaundice and increased respiratory rates. This study found strong correlations between circulating nucleosomes and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that nucleosomes could originate from neutrophil extracellular trap (NET) degradation. High circulating plasma nucleosomes and ELA complexes represent independent risk factors for developing severe complications in scrub typhus. As nucleosomes and histones exposed on NETs are highly cytotoxic to endothelial cells and are strongly pro-coagulant, neutrophil-derived nucleosomes could contribute to vascular damage, the pro-coagulant state and exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and

  17. Increased Nucleosomes and Neutrophil Activation Link to Disease Progression in Patients with Scrub Typhus but Not Murine Typhus in Laos

    PubMed Central

    Paris, Daniel H.; Stephan, Femke; Bulder, Ingrid; Wouters, Diana; van der Poll, Tom; Newton, Paul N.; Day, Nicholas P. J.; Zeerleder, Sacha

    2015-01-01

    Cell-mediated immunity is essential in protection against rickettsial illnesses, but the role of neutrophils in these intracellular vasculotropic infections remains unclear. This study analyzed the plasma levels of nucleosomes, FSAP-activation (nucleosome-releasing factor), and neutrophil activation, as evidenced by neutrophil-elastase (ELA) complexes, in sympatric Lao patients with scrub typhus and murine typhus. In acute scrub typhus elevated nucleosome levels correlated with lower GCS scores, raised respiratory rate, jaundice and impaired liver function, whereas neutrophil activation correlated with fibrinolysis and high IL-8 plasma levels, a recently identified predictor of severe disease and mortality. Nucleosome and ELA complex levels were associated with a 4.8-fold and 4-fold increased risk of developing severe scrub typhus, beyond cut off values of 1,040 U/ml for nucleosomes and 275 U/ml for ELA complexes respectively. In murine typhus, nucleosome levels associated with pro-inflammatory cytokines and the duration of illness, while ELA complexes correlated strongly with inflammation markers, jaundice and increased respiratory rates. This study found strong correlations between circulating nucleosomes and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that nucleosomes could originate from neutrophil extracellular trap (NET) degradation. High circulating plasma nucleosomes and ELA complexes represent independent risk factors for developing severe complications in scrub typhus. As nucleosomes and histones exposed on NETs are highly cytotoxic to endothelial cells and are strongly pro-coagulant, neutrophil-derived nucleosomes could contribute to vascular damage, the pro-coagulant state and exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and

  18. In vitro gas production kinetics and short-chain fatty acid production from rumen incubation of diets supplemented with hop cones (Humulus lupulus L.).

    PubMed

    Lavrenčič, A; Levart, A; Košir, I J; Čerenak, A

    2015-04-01

    The aim of this study was to assess the effects of hop cones (Humulus lupulus L.) from two varieties Aurora and Dana, differing in their α- and β-acid contents, on rumen microbial activity measured with in vitro gas production kinetics and short-chain fatty acids (SCFA) production. Hop cones were added to the total mixed dairy cow ration (CONT) in concentrations simulating a cow's daily intake of 50, 100 and 200 g of hop cones - the concentrations of hop cones expressed on a substrate basis were 43, 82 and 153 mg/g of substrate. Substrates were anaerobically incubated in glass syringes, and gas production kinetic parameters were determined by fitting data with the Gompertz model. Gas produced after 24 h (Gas24), maximum fermentation rate (MFR) and time of maximum fermentation rate (TMFR) were calculated from the estimated gas production kinetic parameters. After 24 h of incubation, the fermentation liquids of each substrate were taken for the determination of SCFA. Increasing the hop cone concentration decreased the total potential gas production, Gas24, MFR and shortened TMFR. The highest hop cone concentration significantly decreased acetic and butyric acid productions and total SCFA production after 24 h of incubation, but not propionic acid production, resulting in a decreased ratio between acetic acid and propionic acid. PMID:25475691

  19. Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

    PubMed Central

    Stabler, S P; Marcell, P D; Podell, E R; Allen, R H; Lindenbaum, J

    1986-01-01

    To determine the incidence of elevated levels of serum methylmalonic acid in patients with cobalamin deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure methylmalonic acid in the serum of 73 patients with clinically confirmed cobalamin deficiency. Values ranged from 55 to 22,300 ng/ml, and 69 of the 73 patients had values above the normal range of 19-76 ng/ml as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum methylmalonic acid was significantly correlated with the serum folate level and the degree of neurologic involvement. Some patients with pernicious anemia who were intermittently treated with cyanocobalamin were found to have elevated serum levels of methylmalonic acid while free of hematologic and neurologic abnormalities. A cobalamin-deficient patient is described with a normal serum cobalamin and an elevated serum methylmalonic acid. We conclude that the ability to measure methylmalonic acid in human serum will be useful in studies designed to determine the incidence of cobalamin deficiency in various patient populations. PMID:3700655

  20. [Determination of fatty acids in vegetable oils using comprehensive two-dimensional gas chromatography coupled to quadropole mass spectrometry].

    PubMed

    Zheng, Yueming; Feng, Feng; Guo, Wei; Chu, Xiaogang; Pan, Jiarong; Jia, Wei

    2012-11-01

    Comprehensive two-dimensional gas chromatography with quadropole mass spectrometry (GC x GC-qMS) was applied to the detection of 31 fatty acids in vegetable oils. The sets of columns, modulation period, scan range of quadropole mass spectrometer were optimized. The results demonstrated that the separation was achieved in 50 min with the column set of DB-1 (30 m x0. 25 mm x 0.25 microm) as the 1st column and DB-Wax (3.2 m x 0.1 mm x 0. 1 microm) as the 2nd column. All fatty acids were accurately and sensitively determined while the modulation period was 3.5 s and the scan range of quadropole MS was m/z 40-350. Most of the fatty acids were identified by NIST library spectra search, the other fatty acid isomers were identified by single standard injection analysis. When applying this method to the real vegetable oil samples, not only the sensitivities were 100 times higher than those obtained with GC-qMS methods, but also some minor fatty acids were identified. This work suggested a new technical approach in analyzing fatty acid components in vegetable oils, which is meaningful to prohibit adulteration and ensuring the quality safety of edible vegetable oils.

  1. Potential interference by free fatty acids in determination of tricyclazole in brown rice by gas chromatography with flame thermionic detection.

    PubMed

    Tsumura, Y; Nakamura, Y; Tonogai, Y; Shibata, T

    1996-01-01

    A convenient method is described for the determination of tricyclazole in brown rice, and the interference of free fatty acids with flame thermionic detection (FTD) is reported for the first time. Brown rice is extracted with acetone, the extract is filtered, and the filtrate is evaporated. To the residue is added 10% (w/v) NaCl solution, and the mixture is extracted with ethyl acetate. The extract is charged on a Sep-Pak Plus silica cartridge. Free fatty acids are removed from the rice by washing with diethyl ether, and tricyclazole is eluted with acetone-n-hexane (1 + 1). Tricyclazole is determined on a DB-1 capillary column by gas chromatography with FTD (GC-FTD). Linoleic acid and oleic acid, which have essentially the same retention time as tricyclazole, cannot be detected by FTD. Thus, without the Sep-Pak Plus silica cleanup, the peak height of tricyclazole in the chromatogram decreased, the extent depending on the concentration of linoleic acid. n-Hexane-acetonitrile partitioning was not used for cleanup because it could not remove 50% of the free fatty acids. Recoveries (mean +/- standard deviation, n = 5) of tricyclazole from rice fortified at 2 and 0.1 ppm were 90.5 +/- 9.4% and 81.3 +/- 10.6%, respectively. The limit of quantitation was 0.05 ppm.

  2. Aromatic aldehyde-catalyzed gas-phase decarboxylation of amino acid anion via imine intermediate: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Xiang, Zhang

    2013-10-01

    It is generally appreciated that carbonyl compound can promote the decarboxylation of the amino acid. In this paper, we have performed the experimental and theoretical investigation into the gas-phase decarboxylation of the amino acid anion catalyzed by the aromatic aldehyde via the imine intermediate on the basis of the tandem mass spectrometry (MS/MS) technique and density functional theory (DFT) calculation. The results show that the aromatic aldehyde can achieve a remarkable catalytic effect. Moreover, the catalytic mechanism varies according to the type of amino acid: (i) The decarboxylation of α-amino acid anion is determined by the direct dissociation of the Csbnd C bond adjacent to the carboxylate, for the resulting carbanion can be well stabilized by the conjugation between α-carbon, Cdbnd N bond and benzene ring. (ii) The decarboxylation of non-α-amino acid anion proceeds via a SN2-like transition state, in which the dissociation of the Csbnd C bond adjacent to the carboxylate and attacking of the resulting carbanion to the Cdbnd N bond or benzene ring take place at the same time. Specifically, for β-alanine, the resulting carbanion preferentially attacks the benzene ring leading to the benzene anion, because attacking the Cdbnd N bond in the decarboxylation can produce the unstable three or four-membered ring anion. For the other non-α-amino acid anion, the Cdbnd N bond preferentially participates in the decarboxylation, which leads to the pediocratic nitrogen anion.

  3. Determination of total acid content in biomass hydrolysates by solvent-assisted and reaction based headspace gas chromatography.

    PubMed

    Huang, Liu-Lian; Hu, Hui-Chao; Chen, Li-Hui

    2015-11-27

    This work reports on a novel method for the determination of total acid (TA) in biomass hydrolysates by a solvent-assisted and reaction-based headspace gas chromatography (HS-GC). The neutralization reaction between the acids in hydrolysates and bicarbonate in an ethanol (50%) aqueous solution was performed in a closed headspace sample vial, from which the carbon dioxide generated from the reaction was detected by HS-GC. It was found that the addition of ethanol can effectively eliminate the precipitation of some organic acids in the biomass hydrolysates. The results showed that the reaction and headspace equilibration can be achieved within 45min at 70°C; the method has a good precision (RSD<3.27%) and accuracy (recovery of 97.4-105%); the limit of quantification is 1.36μmol. The present method is quite suitable to batch analysis of TA content in hydrolysate for the biorefinery related research. PMID:26499971

  4. [The preparation procedure of tests for the gas chromatographic determination of fat acids without preliminary extraction of lipids].

    PubMed

    Aripovskiĭ, A V; Kolesnik, P O; Vezhdel, M I; Titov, V N

    2012-01-01

    The enhancement of the procedure of quantitative gas chromatographic determination of fit acids in biologic liquids samples is proposed. Instead of the conventional Folch procedure of extraction of lipids with subsequent ablution, concentration and methylation of extracts the direct saponification and methylation of vacuum dried liquid samples (50-200 mkl) can be applied. To compare the effectiveness of the proposed and conventional procedures both of them had been applied to evaluate how converge the results of determination of composition of fat acids in whole blood, blood plasma, packed red blood cells, homogenates of hepatic and muscular tissues. The proposed procedure is applied to determine the characteristics of fat acids composition inpatients with ischemic heart disease.

  5. Quantitative enantioseparation of amino acids by comprehensive two-dimensional gas chromatography applied to non-terrestrial samples.

    PubMed

    Myrgorodska, Iuliia; Meinert, Cornelia; Martins, Zita; le Sergeant d'Hendecourt, Louis; Meierhenrich, Uwe J

    2016-02-12

    This work presents an improved analytical procedure for the resolution and quantification of amino acid enantiomers by multidimensional gas chromatography. The procedure contains a derivatization step, by which amino acids were transformed into N(O,S)-ethoxycarbonylheptafluorobutyl esters. It was optimized for the resolution of non-proteinogenic amino acids in the matrix of complex non-terrestrial samples. The procedure has proven to be highly sensitive and shows a wide linearity range with 0.005-3 pmol detection limits for quantitative determinations. The developed procedure was tested on a sample of the Murchison meteorite, for which obtained chromatograms show excellent peak resolution, minimal co-elution and peak overlap. We conclude that comprehensive two dimensional chromatography, in combination with the optimized derivatization method is a highly suitable technique for the analysis of samples with very limited quantities and containing potentially prebiotic molecules, such as interstellar ice analogs and meteorites. PMID:26803906

  6. Quantitative enantioseparation of amino acids by comprehensive two-dimensional gas chromatography applied to non-terrestrial samples.

    PubMed

    Myrgorodska, Iuliia; Meinert, Cornelia; Martins, Zita; le Sergeant d'Hendecourt, Louis; Meierhenrich, Uwe J

    2016-02-12

    This work presents an improved analytical procedure for the resolution and quantification of amino acid enantiomers by multidimensional gas chromatography. The procedure contains a derivatization step, by which amino acids were transformed into N(O,S)-ethoxycarbonylheptafluorobutyl esters. It was optimized for the resolution of non-proteinogenic amino acids in the matrix of complex non-terrestrial samples. The procedure has proven to be highly sensitive and shows a wide linearity range with 0.005-3 pmol detection limits for quantitative determinations. The developed procedure was tested on a sample of the Murchison meteorite, for which obtained chromatograms show excellent peak resolution, minimal co-elution and peak overlap. We conclude that comprehensive two dimensional chromatography, in combination with the optimized derivatization method is a highly suitable technique for the analysis of samples with very limited quantities and containing potentially prebiotic molecules, such as interstellar ice analogs and meteorites.

  7. The acidity and proton affinity of the damaged base 1,N6-ethenoadenine in the gas phase versus in solution: intrinsic reactivity and biological implications.

    PubMed

    Liu, Min; Xu, Meng; Lee, Jeehiun K

    2008-08-01

    1,N(6)-ethenoadenine (epsilonA) is a highly mutagenic lesion that is excised from human DNA by the enzyme alkyladenine DNA glycosylase (AAG). In an effort to understand the intrinsic properties of 1,N(6)-ethenoadenine, we examined its gas phase acidity and proton affinity using quantum mechanical calculations and mass spectrometric experimental methods. We measure two acidities for epsilonA: a more acidic site (DeltaH(acid) = 332 kcal mol(-1); DeltaG(acid) = 325 kcal mol(-1)) and a less acidic site (DeltaH(acid) = 367 kcal mol(-1); DeltaG(acid) = 360 kcal mol(-1)). We also find that the proton affinity of the most basic site of 1,N(6)-ethenoadenine is 232-233 kcal mol(-1) (GB = 224 kcal mol(-1)). These measurements, when compared to calculations, establish that, under our experimental conditions, we have only the canonical tautomer of 1,N(6)-ethenoadenine present. We also compare the gas phase acidic properties of epsilonA with that of the normal bases adenine and guanine and find that epsilonA is the most acidic. This supports the theory that AAG and other related enzymes may cleave damaged bases as anions. Furthermore, comparison of the gas phase and aqueous acidities indicates that the nonpolar environment of the enzyme enhances the acidity differences of epsilonA versus adenine and guanine. PMID:18593189

  8. Theoretical study of interactions between cysteine and perfluoropropanoic acid in gas and aqueous phase

    NASA Astrophysics Data System (ADS)

    Holmes, Tiffani M.; Doskocz, Jacek; Wright, Terrance; Hill, Glake A.

    The interaction of perfluoropropanoic acid (PFPA) with the amino acid cysteine was investigated using density functional theory. Previous studies suggest that the peroxisome proliferator chemical, perfluorooctanoic acid, is circulated throughout the body by way of sulfur-containing amino acids. We present conformational analysis of the interactions of PFPA, a small model of perfluorooctanoic acid, with the sulfur-containing amino acid which occur by the process of hydrogen bonding, in which the hydrogen of the sulfhydryl group interacts with the carboxyl oxygen, and the amino nitrogen forms a hydrogen bond with the hydrogen of the bond OH group of the fluorinated alkyl. We also show in our structures a recently characterized weak nonbonded interaction between divalent sulfur and a main chain carboxyl oxygen in proteins. B3LYP calculated free energies and interaction energies predict low-energy, high-interaction conformations for complex systems of perfluorinated fatty acid interactions with cysteine.

  9. HYDROFLUORIC ACID SCRUBBER SYSTEMS

    SciTech Connect

    PANESKO JV; MERRITT HD

    2011-05-18

    Each year over a million gallons of water are used to scrub hydrogen fluoride (HP) vapors from waste off-gas streams. Use of other potential scrubber solutions such as potassium hydroxide (KOH), aluminum nitrate nonahydrate (ANN), and monobasic aluminum nitrate (monoban) would result in significant volume reductions. A laboratory study was initiated to (1) demonstrate the effectiveness of these scrubber solutions to sorb HF, (2) determine if unexpected reactions occurred at flowsheet conditions, and (3) determine the consequences of deviation from flowsheet conditions. Caustic or aluminum scrubber solutions remove hydrogen fluoride from off-gas streams. Solids which appear with aluminum could be avoided by heating the scrubber solution.

  10. Advanced separation technology for flue gas cleanup. Topical report

    SciTech Connect

    Bhown, A.S.; Alvarado, D.; Pakala, N.; Ventura, S.

    1995-01-01

    The objective of this work is to develop a novel system for regenerable SO{sub 2} and NO{sub x} scrubbing of flue gas that focuses on (1) a novel method for regenerating spent SO{sub 2} scrubbing liquor and (2) novel chemistry for reversible absorption of NO{sub x}. In addition, high efficiency hollow fiber contactors (HFC) are proposed as the devices for scrubbing the SO{sub 2} and NO{sub x} from the flue gas. The system will be designed to remove more than 95% of the SO{sub 2} and more than 75% of the NO{sub x} from flue gases typical of pulverized coal-fired power plants at a cost that is at least 20% less than combined wet limestone scrubbing of SO{sub x} and selective catalytic reduction of NO{sub x}. The process will generate only marketable by-products. Our approach is to reduce the capital cost by using high-efficiency hollow fiber devices for absorbing and desorbing the SO{sub 2} and NO{sub x}. We will also introduce new process chemistry to minimize traditionally well-known problems with SO{sub 2} and NO{sub x} absorption and desorption. Our novel chemistry for scrubbing NO{sub x} will consist of water-soluble phthalocyanine compounds invented by SRI as well as polymeric forms of Fe{sup ++} complexes similar to traditional NO{sub x} scrubbing media. The final novelty of our approach is the arrangement of the absorbers in cassette (stackable) form so that the NO{sub x} absorber can be on top of the SO{sub x} absorber. This arrangement is possible only because of the high efficiency of the hollow fiber scrubbing devices, as indicated by our preliminary laboratory data. This arrangement makes it possible for the SO{sub 2} and NO{sub x} scrubbing chambers to be separate without incurring the large ducting and gas pressure drop costs necessary if a second conventional absorber vessel were used. Because we have separate scrubbers, we will have separate liquor loops and simplify the chemical complexity of simultaneous SO{sub 2}/NO{sub x} scrubbing.

  11. Effects of fire on composition, biomass, and nutrients in oak scrub vegetation on John F. Kennedy Space Center, Florida

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Hinkle, C. Ross

    1987-01-01

    Four stands of oak scrub two, four, eight, and 25 years since fire were sampled with permanent 15 m line transects. Percent cover by species was determined. Plant samples were analyzed for a variety of substances. Transects were resurveyed in 1985 for vegetation parameters. Nutrient pools in biomass were calculated from biomass data and tissue nutrient concentrations. Soil nutrient pools were calculated from nutrient concentrations and bulk density. Species distribution and soil chemical properties were found to be closely related to water table depth. The following fire-related conclusions are reached: (1) major structural changes occur in scrub after fire in that shrub height is reduced and requires four to six years to exceed 1 m; (2) reduction in shrub height affects the suitability of scrub for the Florida scrub jay (3) live biomass increases with time since fire; (4) nutrient concentrations in live biomass do not change with time since fire; (5) species composition and richness are little changed after fire; and (6) imposition of a continued regime of burning on a three-year cycle may have adverse impacts not indicated by the recovery of scrub from a single fire.

  12. The Correlation of Endoscopic Findings and Clinical Features in Korean Patients with Scrub Typhus: A Cohort Study.

    PubMed

    Lee, Jun; Kim, Dong-Min; Yun, Na Ra; Kim, Young Dae; Park, Chan Guk; Kim, Man Woo

    2016-01-01

    Scrub typhus is an infectious disease caused by Orientia tsutsugamushi-induced systemic vasculitis, but the involvement of the gastrointestinal tract and the endoscopic findings associated with scrub typhus are not well understood. We performed a prospective study and recommend performing esophagogastroduodenoscopy (EGD) for all possible scrub typhus patients, regardless of gastrointestinal symptoms. Gastrointestinal symptoms, endoscopic findings and clinical severity based on organ involvement and ICU admission were analyzed. Gastrointestinal symptoms occurred in up to 76.4% of scrub typhus patients. The major endoscopic findings were ulcers (43/127, 33.9%). Interestingly, 7.1% (9/127) of the patients presented with esophageal candidiasis. There was no correlation between the presence or absence of gastrointestinal symptoms and the endoscopic grade (P = 0.995). However, there was a positive correlation between the clinical severity and the endoscopic findings (P = 0.001). Sixty-three percent of the patients presented with erosion or ulcers on prospectively performed endoscopic evaluations, irrespective of gastrointestinal symptoms. Gastrointestinal symptoms did not reflect the need for endoscopy. Scrub typhus patients could have significant endoscopic abnormalities even in the absence of gastrointestinal symptoms. PMID:27195943

  13. Clinical and Epidemiological Characteristics of Scrub Typhus and Murine Typhus among Hospitalized Patients with Acute Undifferentiated Fever in Northern Vietnam.

    PubMed

    Hamaguchi, Sugihiro; Cuong, Ngo Chi; Tra, Doan Thu; Doan, Yen Hai; Shimizu, Kenta; Tuan, Nguyen Quang; Yoshida, Lay-Myint; Mai, Le Quynh; Duc-Anh, Dang; Ando, Shuji; Arikawa, Jiro; Parry, Christopher M; Ariyoshi, Koya; Thuy, Pham Thanh

    2015-05-01

    A descriptive study on rickettsiosis was conducted at the largest referral hospital in Hanoi, Vietnam, to identify epidemiological and clinical characteristics of specific rickettsiosis. Between March 2001 and February 2003, we enrolled 579 patients with acute undifferentiated fever (AUF), excluding patients with malaria, dengue fever, and typhoid fever, and serologically tested for Orientia tsutsugamushi and Rickettsia typhi. Of the patients, 237 (40.9%) and 193 (33.3%) had scrub and murine typhus, respectively, and 149 (25.7%) had neither of them (non-scrub and murine typhus [non-ST/MT]). The proportion of murine typhus was highest among patients living in Hanoi whereas that of scrub typhus was highest in national or regional border areas. The presence of an eschar, dyspnea, hypotension, and lymphadenopathy was significantly associated with a diagnosis of scrub typhus (OR = 46.56, 10.90, 9.01, and 7.92, respectively). Patients with murine typhus were less likely to have these findings but more likely to have myalgia, rash, and relative bradycardia (OR = 1.60, 1.56, and 1.45, respectively). Scrub typhus and murine typhus were shown to be common causes of AUF in northern Vietnam although the occurrence of spotted fever group rickettsiae was not determined. Clinical and epidemiological information may help local clinicians make clinical diagnosis of specific rickettsioses in a resource-limited setting.

  14. Simultaneous determination of sorbic and benzoic acids in milk products using an optimised microextraction technique followed by gas chromatography.

    PubMed

    Abedi, Abdol-Samad; Mohammadi, Abdorreza; Azadniya, Ebrahim; Mortazavian, Amir Mohammad; Khaksar, Ramin

    2014-01-01

    A rapid and reliable method for direct determination of sorbic and benzoic acids in milk products was developed by dispersive liquid-liquid microextraction (DLLME) and gas chromatography with flame ionisation detector (GC-FID). A response surface methodology (RSM) based on a central composite design (CCD) was applied for optimisation of the main variables, such as volume of extraction and dispersive solvents, pH and salt effect. The primary extraction of sorbic and benzoic acids were performed in 8 mL NaOH (0.1 M) in a closed-vessel system. Carrez solutions (potassium hexaferrocyanide and zinc acetate) were used for protein sedimentation. The best simultaneous extraction efficiency was identified using acetone and 1-octanal as dispersive and extraction solvents, respectively. For DLLME, central composite design resulted in the optimised values of microextraction parameters as follows: 475 µL of dispersive and 60 µL of extraction solvents, 2 g NaCl at pH 2.5. Under optimum conditions, the calibration curve was linear over the range 0.1-50 μg mL(-1) and the square of correlation coefficient (R(2)) was 0.9992 for sorbic acid and 0.9994 for benzoic acid. Relative standard deviation (RSD %) was 6.1% and 3.1% (n = 5) for sorbic and benzoic acids, respectively. Limits of detection were 150 ng g(-1) for sorbic acid and 140 ng g(-1) for benzoic acid and recoveries were 88% and 103.7% respectively. Good reproducibility (RSD %), short extraction time and no matrix interference were advantages of the proposed method which was successfully applied to the determination of sorbic and benzoic acids in milk products. PMID:24397823

  15. An outbreak investigation of scrub typhus in Western Province, Solomon Islands, 2014

    PubMed Central

    Marks, Michael; Joshua, Cynthia; Longbottom, Jenny; Longbottom, Katherine; Sio, Alison; Puiahi, Elliot; Jilini, Greg; Stenos, John; Dalipanda, Tenneth

    2016-01-01

    Objective To identify the etiology and risk factors of undifferentiated fever in a cluster of patients in Western Province, Solomon Islands, May 2014. Methods An outbreak investigation with a case control study was conducted. A case was defined as an inpatient in one hospital in Western Province, Solomon Islands with high fever (> 38.5 °C) and a negative malaria microscopy test admitted between 1 and 31 May 2014. Asymptomatic controls matched with the cases residentially were recruited in a ratio of 1:2. Serum samples from the subjects were tested for rickettsial infections using indirect micro-immunofluorescence assay. Results Nine cases met the outbreak case definition. All cases were male. An eschar was noted in five cases (55%), and one developed pneumonitis. We did not identify any environmental factors associated with illness. Serum samples of all five follow-up cases (100%) had strong-positive IgG responses to scrub typhus. All but one control (10%) had a moderate response against scrub typhus. Four controls had low levels of antibodies against spotted fever group rickettsia, and only one had a low-level response to typhus group rickettsia. Discussion This outbreak represents the first laboratory-confirmed outbreak of scrub typhus in the Western Province of Solomon Islands. The results suggest that rickettsial infections are more common than currently recognized as a cause of an acute febrile illness. A revised clinical case definition for rickettsial infections and treatment guidelines were developed and shared with provincial health staff for better surveillance and response to future outbreaks of a similar kind.

  16. Sample Results From The Extraction, Scrub, And Strip Test For The Blended NGS Solvent

    SciTech Connect

    Washington, A. L. II; Peters, T. B.

    2014-03-03

    This report summarizes the results of the extraction, scrub, and strip testing for the September 2013 sampling of the Next Generation Solvent (NGS) Blended solvent from the Modular Caustic Side-Solvent Extraction Unit (MCU) Solvent Hold Tank. MCU is in the process of transitioning from the BOBCalixC6 solvent to the NGS Blend solvent. As part of that transition, MCU has intentionally created a blended solvent to be processed using the Salt Batch program. This sample represents the first sample received from that blended solvent. There were two ESS tests performed where NGS blended solvent performance was assessed using either the Tank 21 material utilized in the Salt Batch 7 analyses or a simulant waste material used in the V-5/V-10 contactor testing. This report tabulates the temperature corrected cesium distribution, or DCs values, step recovery percentage, and actual temperatures recorded during the experiment. This report also identifies the sample receipt date, preparation method, and analysis performed in the accumulation of the listed values. The calculated extraction DCs values using the Tank 21H material and simulant are 59.4 and 53.8, respectively. The DCs values for two scrub and three strip processes for the Tank 21 material are 4.58, 2.91, 0.00184, 0.0252, and 0.00575, respectively. The D-values for two scrub and three strip processes for the simulant are 3.47, 2.18, 0.00468, 0.00057, and 0.00572, respectively. These values are similar to previous measurements of Salt Batch 7 feed with lab-prepared blended solvent. These numbers are considered compatible to allow simulant testing to be completed in place of actual waste due to the limited availability of feed material.

  17. A new surgical handwashing and hand antisepsis from scrubbing to rubbing.

    PubMed

    Furukawa, Kiyonori; Ogawa, Rho; Norose, Yoshihiro; Tajiri, Takashi

    2004-06-01

    In 2002, the Centers for Disease Control and Prevention (CDC) published guidelines for surgical handwashing and hand antisepsis on the Internet. According to these guidelines, we revised our surgical handwashing method from scrubbing with brushes to rubbing with antiseptic. The new method consists of scrubbing around the nails with brushes and rubbing the hands and arms with antiseptic from the elbow to the antebrachium. A total of 182 surgeons and operating-room nurses participated in the current study. Bacterial contamination was investigated using the glove-juice method. The new surgical handwashing method is simple, and requires only a short time to perform (2 minutes 50 seconds). The bacterial examination confirmed that rubbing the hands with antiseptic was significantly more effective than scrubbing with brushes. In terms of sterilization or prolonged effects, 4% chlor-hexidine gluconate (CHG) was superior to 7.5% povidone-iodine (PVI) throughout a 3-hour period after hand antisepsis. Although bacterial counts were increased 3 hours after the beginning of surgery, additional hand rubbing with 0.2% chlorhexidine-83% ethanol (Hibisoft(TM)) was effective in suppressing the number of bacteria. Hibisoft(TM) successfully prolonged sterilization for more than 3 hours. For long surgical procedures, CHG should be used as an antiseptic and gloves should be changed every 3 hours, alcohol-based hand rubbing should also be performed 3 hours after the initial handwashing. This new technique will be included in the OSCE curriculum to ensure its standardization. Moreover, in-depth education regarding central operating-room practices is desired.

  18. Nutrient enrichment intensifies hurricane impact in scrub mangrove ecosystems in the Indian River Lagoon, Florida, USA.

    PubMed

    Feller, Ilka C; Dangremond, Emily M; Devlin, Donna J; Lovelock, Catherine E; Proffitt, C Edward; Rodriguez, Wilfrid

    2015-11-01

    Mangroves are an ecological assemblage of trees and shrubs adapted to grow in intertidal environments along tropical, subtropical, and warm temperate coasts. Despite repeated demonstrations of their ecologic and economic value, multiple stressors including nutrient over-enrichment threaten these and other coastal wetlands globally. These ecosystems will be further stressed if tropical storm intensity and frequency increase in response to global climate changes. These stressors will likely interact, but the outcome of that interaction is uncertain. Here, we examined potential interaction between nutrient over-enrichment and the September 2004 hurricanes. Hurricanes Frances and Jeanne made landfall along Florida's Indian River Lagoon and caused extensive damage to a long-term fertilization experiment in a mangrove forest, which previously revealed that productivity was nitrogen (N) limited across the forest and, in particular, that N enrichment dramatically increased growth rates and aboveground biomass of stunted Avicennia germinans trees in the interior scrub zone. During the hurricanes, these trees experienced significant defoliation with three to four times greater reduction in leaf area index (LAI) than control trees. Over the long-term, the +N scrub trees took four years to recover compared to two years for controls. In the adjacent fringe and transition zones, LAI was reduced by > 70%, but with no differences based on zone or fertilization treatment. Despite continued delayed mortality for at least five years after the storms, LAI in the fringe and transition returned to pre-hurricane conditions in two years. Thus, nutrient over-enrichment of the coastal zone will increase the productivity of scrub mangroves, which dominate much of the mangrove landscape in Florida and the Caribbean; however, that benefit is offset by a decrease in their resistance and resilience to hurricane damage that has the potential to destabilize the system. PMID:27070015

  19. Scrub typhus associated with hemophagocytic lymphohistiocytosis: A report of six pediatric patients

    PubMed Central

    Jin, Yingkang; Huang, Li; Fan, Huifeng; Lu, Gen; Xu, Yi; Wu, Zhiyuan

    2016-01-01

    Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune disorder that may be inherited or secondary to infection, malignancy or rheumatological disease. The aim of the present study was to highlight the clinical features of scrub typhus-associated HLH in children. A retrospective study was performed on 6 pediatric patients with scrub typhus-associated HLH. For each patient, medical records were reviewed and analyzed, and demographic, clinical and laboratory data and outcomes were collected. The duration of fever prior to admission ranged between 4 and 12 days. All patients exhibited persistent or intermittent fever, eschar, hepatosplenomegaly and lymphadenopathy at the time of diagnosis. Five patients experienced acute respiratory distress syndrome and disseminated intravascular coagulation (DIC) during hospitalization. Thrombocytopenia was detected in all patients with cytopenia involving two or three cell types, simultaneously. Coagulopathy with prolonged prothrombin time and/or activated partial thromboplastin time were noted in all patients. Markedly elevated serum ferritin levels (>1,500 µg/ml) were identified in all patients. Elevated lactate dehydrogenase (>1,000 U/l) was detected in 4 (66.7%) patients and elevated alanine aminotransferase was exhibited by 5 (83/3%) patients. Lung infiltrates and consolidation were the most common imaging findings. Only 1 patient succumbed, with DIC and multi-organ failure. Of the survivors, 1 patient was lost to follow-up, and the remaining patients are in remission with excellent general health, to date. In conclusion, HLH should be considered in severe pediatric cases of scrub typhus. Upon the early recognition of this syndrome, prompt and supportive treatment in the pediatric intensive care unit are vital.

  20. Ocular surface discomfort and Demodex: effect of tea tree oil eyelid scrub in Demodex blepharitis.

    PubMed

    Koo, Hyun; Kim, Tae Hyung; Kim, Kyoung Woo; Wee, Sung Wook; Chun, Yeoun Sook; Kim, Jae Chan

    2012-12-01

    The purpose of this study was to evaluate the relation between ocular discomfort and ocular Demodex infestation, and therapeutic effects of tea tree oil (TTO) in Demodex blepharitis patients. Three hundred and thirty-five patients with ocular discomfort were evaluated for ocular Demodex infestation and subjective symptoms with ocular surface discomfort index (OSDI) score. Among them, Demodex-infested patients were randomized to receive either eyelid scrubbing with TTO (TTO group,106 patients) or without TTO (Control group, 54 patients) for 1 month. Demodex were found in 84% of patients with ocular discomfort. The number of Demodex was significantly correlated with age (P = 0.04) and OSDI score (P = 0.024). After eyelid scrub treatment, Demodex count was reduced from 4.0 ± 2.5 to 3.2 ± 2.3 in the TTO group (P = 0.004) and from 4.3 ± 2.7 to 4.2 ± 2.5 in the control group (P = 0.27). Also, OSDI score was reduced from 34.5 ± 10.7 to 24.1 ± 11.9 in the TTO group (P = 0.001) and from 35.3 ± 11.6 to 27.5 ± 12.8 in the control group (P = 0.04). In conclusion, Demodex number showed a significant positive correlation with age and subjective ocular discomfort. The tea tree oil eyelid scrub treatment is effective for eliminating ocular Demodex and improving subjective ocular symptoms.

  1. Scrub typhus associated with hemophagocytic lymphohistiocytosis: A report of six pediatric patients

    PubMed Central

    Jin, Yingkang; Huang, Li; Fan, Huifeng; Lu, Gen; Xu, Yi; Wu, Zhiyuan

    2016-01-01

    Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune disorder that may be inherited or secondary to infection, malignancy or rheumatological disease. The aim of the present study was to highlight the clinical features of scrub typhus-associated HLH in children. A retrospective study was performed on 6 pediatric patients with scrub typhus-associated HLH. For each patient, medical records were reviewed and analyzed, and demographic, clinical and laboratory data and outcomes were collected. The duration of fever prior to admission ranged between 4 and 12 days. All patients exhibited persistent or intermittent fever, eschar, hepatosplenomegaly and lymphadenopathy at the time of diagnosis. Five patients experienced acute respiratory distress syndrome and disseminated intravascular coagulation (DIC) during hospitalization. Thrombocytopenia was detected in all patients with cytopenia involving two or three cell types, simultaneously. Coagulopathy with prolonged prothrombin time and/or activated partial thromboplastin time were noted in all patients. Markedly elevated serum ferritin levels (>1,500 µg/ml) were identified in all patients. Elevated lactate dehydrogenase (>1,000 U/l) was detected in 4 (66.7%) patients and elevated alanine aminotransferase was exhibited by 5 (83/3%) patients. Lung infiltrates and consolidation were the most common imaging findings. Only 1 patient succumbed, with DIC and multi-organ failure. Of the survivors, 1 patient was lost to follow-up, and the remaining patients are in remission with excellent general health, to date. In conclusion, HLH should be considered in severe pediatric cases of scrub typhus. Upon the early recognition of this syndrome, prompt and supportive treatment in the pediatric intensive care unit are vital. PMID:27698778

  2. Nutrient enrichment intensifies hurricane impact in scrub mangrove ecosystems in the Indian River Lagoon, Florida, USA.

    PubMed

    Feller, Ilka C; Dangremond, Emily M; Devlin, Donna J; Lovelock, Catherine E; Proffitt, C Edward; Rodriguez, Wilfrid

    2015-11-01

    Mangroves are an ecological assemblage of trees and shrubs adapted to grow in intertidal environments along tropical, subtropical, and warm temperate coasts. Despite repeated demonstrations of their ecologic and economic value, multiple stressors including nutrient over-enrichment threaten these and other coastal wetlands globally. These ecosystems will be further stressed if tropical storm intensity and frequency increase in response to global climate changes. These stressors will likely interact, but the outcome of that interaction is uncertain. Here, we examined potential interaction between nutrient over-enrichment and the September 2004 hurricanes. Hurricanes Frances and Jeanne made landfall along Florida's Indian River Lagoon and caused extensive damage to a long-term fertilization experiment in a mangrove forest, which previously revealed that productivity was nitrogen (N) limited across the forest and, in particular, that N enrichment dramatically increased growth rates and aboveground biomass of stunted Avicennia germinans trees in the interior scrub zone. During the hurricanes, these trees experienced significant defoliation with three to four times greater reduction in leaf area index (LAI) than control trees. Over the long-term, the +N scrub trees took four years to recover compared to two years for controls. In the adjacent fringe and transition zones, LAI was reduced by > 70%, but with no differences based on zone or fertilization treatment. Despite continued delayed mortality for at least five years after the storms, LAI in the fringe and transition returned to pre-hurricane conditions in two years. Thus, nutrient over-enrichment of the coastal zone will increase the productivity of scrub mangroves, which dominate much of the mangrove landscape in Florida and the Caribbean; however, that benefit is offset by a decrease in their resistance and resilience to hurricane damage that has the potential to destabilize the system.

  3. Synthesis of Scrub-Oak Ecosystem Responses to Elevated CO2

    SciTech Connect

    Hungate, Bruce

    2014-11-07

    This report summarizes a synthesis project of a long-term global change experiment conducted at the Kennedy Space Center, Florida, investigating how increasing concentrations of atmospheric carbon dioxide (CO2) influences the functioning of a fire-dominated scrub-oak ecosystem. The experiment began in 1996 and ended in 2007. Results presented here summarize the effects of elevated CO2 on plant growth, soil processes, carbon and nutrient cycling, and other responses. Products include archived data from the experiment, as well as six publications in the peer-reviewed literature.

  4. BUILDING MATERIALS MADE FROM FLUE GAS DESULFURIZATION BY-PRODUCTS

    SciTech Connect

    Michael W. Grutzeck; Maria DiCola; Paul Brenner

    2006-03-30

    Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used in place of conventional Portland cement based products such as retaining wall bricks and pavers.

  5. Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

    PubMed

    Wu, Qinglong; Shah, Nagendra P

    2015-02-01

    High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive.

  6. Adsorption-induced coal swelling and stress: Implications for methane production and acid gas sequestration into coal seams

    NASA Astrophysics Data System (ADS)

    Cui, Xiaojun; Bustin, R. Marc; Chikatamarla, Laxmi

    2007-10-01

    Sequestration of CO2 and H2S into deep unminable coal seams is an attractive option to reduce their emission into atmosphere and at the same time displace preadsorbed CH4 which is a clean energy resource. High coal seam permeability is required for efficient and practical sequestration of CO2 and H2S and recovery of CH4. However, adsorption of CO2 and H2S into coals induces strong swelling of the coal matrix (volumetric strain) and thus reduces significantly coal permeability by narrowing and even closing fracture apertures. Our experimental data on three western Canadian coals show that the adsorption-induced volumetric strain is approximately linearly proportional to the volume of adsorbed gas, and for the same gas, different coals have very similar volumetric strain coefficient. Impacts of adsorption-induced swelling on stress and permeability around wellbores were analytically investigated using our developed stress and permeability models. Our model results indicate that adsorption-induced volumetric strain has significant controls on stress and permeability of producing and sequestrating coal seams and consequently the potential of acid gas sequestration. Coal seams may undergo >10 times enhancement of permeability around CH4-producing wellbores due to a reduction in effective stress as a result of coal shrinking caused by methane desorption accompanying a reduction in reservoir pressure. Injection of H2S and CO2 on the other hand results in strong sorption-induced swelling and a marked increase in effective stress which in turn leads to a reduction of coal seam permeability of up to several orders of magnitude. Injection of mixtures of N2 and CO2 such as found in flue gas results in weaker swelling, the amount of which varies with gas composition, and provides the greatest opportunity of sequestering CO2 and secondary recovery of CH4 for most coals. Because of the marked swelling of coal in the presence of H2S, even minor amounts of H2S result in a marked

  7. Gas chromatography-mass spectrometry analysis of fatty acid profiles of Antarctic and non-Antarctic yeasts.

    PubMed

    Bhuiyan, Mohammad; Tucker, David; Watson, Kenneth

    2014-08-01

    The fatty acid profiles of Antarctic (n = 7) and non-Antarctic yeasts (n = 7) grown at different temperatures were analysed by gas chromatography-mass spectrometry. The Antarctic yeasts were enriched in oleic 18:1 (20-60 %), linoleic 18:2 (20-50 %) and linolenic 18:3 (5-40 %) acids with lesser amounts of palmitic 16:0 (<15 %) and palmitoleic 16:1 (<10 %) acids. The non-Antarctic yeasts (n = 4) were enriched in 18:1 (20-55 %, with R. mucilaginosa at 75-80 %) and 18:2 (10-40 %) with lesser amounts of 16:0 (<20 %), 16:1 (<20 %) and stearic 18:0 (<10 %) acids. By contrast, Saccharomyces cerevisiae strains (n = 3) were enriched in 16:1 (30-50 %) and 18:1 (20-40 %) with lesser amounts of 16:0 (10-25 %) and 18:0 (5-10 %) acids. Principal component analysis grouped the yeasts into three clusters, one belonging to the S. cerevisiae strains (enriched in 16:0, 16:1 and 18:1), one to the other non-Antarctic yeasts (enriched in 18:1 and 18:2) and the third to the Antarctic yeasts (enriched in 18:2 and 18:3).

  8. Direct comparison of fatty acid ratios in single cellular lipid droplets as determined by comparative Raman spectroscopy and gas chromatography.

    PubMed

    Schie, Iwan W; Nolte, Lena; Pedersen, Theresa L; Smith, Zach; Wu, Jian; Yahiatène, Idir; Newman, John W; Huser, Thomas

    2013-11-01

    Cellular lipid droplets are the least studied and least understood cellular organelles in eukaryotic and prokaryotic cells. Despite a significant body of research studying the physiology of lipid droplets it has not yet been possible to fully determine the composition of individual cellular lipid droplets. In this paper we use Raman spectroscopy on single cellular lipid droplets and least-squares fitting of pure fatty acid spectra to determine the composition of individual lipid droplets in cells after treatment with different ratios of oleic and palmitic acid. We validate the results of the Raman spectroscopy-based single lipid droplet analysis with results obtained by gas chromatography analysis of millions of cells, and find that our approach can accurately predict the relative amount of a specific fatty acid in the lipid droplet. Based on these results we show that the fatty acid composition in individual lipid droplets is on average similar to that of all lipid droplets found in the sample. Furthermore, we expand this approach to the investigation of the lipid composition in single cellular peroxisomes. We determine the location of cellular peroxisomes based on two-photon excitation fluorescence (TPEF) imaging of peroxisomes labeled with the green fluorescent protein, and successive Raman spectroscopy of peroxisomes. We find that in some cases peroxisomes can produce a detectable CARS signal, and that the peroxisomal Raman spectra exhibit an oleic acid-like signature.

  9. Evaluation of the retention pattern on ionic liquid columns for gas chromatographic analyses of fatty acid methyl esters.

    PubMed

    Lin, Chen-Chen; Wasta, Ziar; Mjøs, Svein A

    2014-07-11

    Fatty acid methyl esters from marine sources were analyzed by gas chromatography-mass spectrometry on three ionic liquid columns, SLB-IL61, SLB-IL82 and SLB-IL100 (Supelco). Retention indices (equivalent chain lengths) are reported for more than 100 compounds and the overlap patterns are evaluated from these data. The influence of chromatographic conditions on the retention indices of unsaturated fatty acid methyl esters is also evaluated. Compared to typical alternative phases the retention patterns on all three columns are highly dependent on the conditions. The SLB-IL61 phase had overlaps between nutritionally important fatty acids that could not be resolved by changing the chromatographic conditions. This column is therefore regarded as unsuitable for clinical and nutritional studies of the fatty acid composition, but similar overlaps may be avoided on IL82 and IL100. On all three columns double bonds close to the carboxyl group in the analytes contribute with limited retention, which makes it challenging to predict the retention of polyunsaturated fatty acid methyl esters. PMID:24873965

  10. Kinetics and methane gas yields of selected C1 to C5 organic acids in anaerobic digestion.

    PubMed

    Yang, Yu; Chen, Qian; Guo, Jialiang; Hu, Zhiqiang

    2015-12-15

    Volatile fatty acids (VFAs) and other short-chain organic acids such as lactic and pyruvic acids are intermediates in anaerobic organic degradation. In this study, anaerobic degradation of seven organic acids in salt form was investigated, including formate (C1), acetate (C2), propionate (C3), pyruvate (C3), lactate (C3), butyrate (C4), and valerate (C5). Microbial growth kinetics on these organic acids were determined individually at 37 °C through batch anaerobic digestion tests by varying substrate concentrations from 250 to 4000 mg COD/L. The cumulative methane generation volume was determined real-time by respirometry coupled with gas chromatographic analysis while methane yield and related kinetics were calculated. The methane gas yields (fe, mg CH4 COD/mg substrate COD) from anaerobic degradation of formate, acetate, propionate, pyruvate, lactate, butyrate, and valerate were 0.44 ± 0.27, 0.58 ± 0.05, 0.53 ± 0.18, 0.24 ± 0.05, 0.17 ± 0.05, 0.43 ± 0.15, 0.49 ± 0.11, respectively. Anaerobic degradation of formate showed self-substrate inhibition at the concentrations above 3250 mg COD/L. Acetate, propionate, pyruvate, butyrate, lactate, and valerate did not inhibit methane production at the highest concentrations tested (i.e., 4000 mg COD/L). Microbes growing on acetate had the highest overall specific growth rate (0.30 d(-1)) in methane production. For comparison, the specific microbial growth rates on formate, propionate, pyruvate, butyrate, lactate, and valerate for methane production were 0.10, 0.06, 0.08, 0.07, 0.05, 0.15 d(-1), respectively.

  11. Fatty acid constituents of Peganum harmala plant using Gas Chromatography–Mass Spectroscopy

    PubMed Central

    Moussa, Tarek A.A.; Almaghrabi, Omar A.

    2015-01-01

    Fatty acid contents of the Peganum harmala plant as a result of hexane extraction were analyzed using GC–MS. The saturated fatty acid composition of the harmal plant was tetradecanoic, pentadecanoic, tridecanoic, hexadecanoic, heptadecanoic and octadecanoic acids, while the saturated fatty acid derivatives were 12-methyl tetradecanoic, 5,9,13-trimethyl tetradecanoic and 2-methyl octadecanoic acids. The most abundant fatty acid was hexadecanoic with concentration 48.13% followed by octadecanoic with concentration 13.80%. There are four unsaturated fatty acids called (E)-9-dodecenoic, (Z)-9-hexadecenoic, (Z,Z)-9,12-octadecadienoic and (Z,Z,Z)-9,12,15-octadecatrienoic. The most abundant unsaturated fatty acid was (Z,Z,Z)-9,12,15-octadecatrienoic with concentration 14.79% followed by (Z,Z)-9,12-octadecadienoic with concentration 10.61%. Also, there are eight non-fatty acid compounds 1-octadecene, 6,10,14-trimethyl-2-pentadecanone, (E)-15-heptadecenal, oxacyclohexadecan-2 one, 1,2,2,6,8-pentamethyl-7-oxabicyclo[4.3.1]dec-8-en-10-one, hexadecane-1,2-diol, n-heneicosane and eicosan-3-ol. PMID:27081366

  12. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  13. Acidic methanolysis v. alkaline saponification in gas chromatographic characterization of mycobacteria: differentiation between Mycobacterium avium-intracellulare and Mycobacterium gastri.

    PubMed

    Larsson, L

    1983-08-01

    Mycobacterium avium-intracellulare and M.gastri were analyzed with capillary gas chromatography after each strain had been subjected to acidic methanolysis or to alkaline saponification followed by methylation. Prominent peaks of myristic, palmitoleic, palmitic, oleic, stearic and tuberculostearic acids were found in the chromatograms of both species, whereas 2-octadecanol and 2-eicosanol were detected only in M. avium-intracellulare. In initial runs, both of the derivatization principles yielded virtually identical chromatograms for a given strain. After repeated injections of extracts from alkaline saponification, however, the alcohol peaks showed pronounced tailing and finally almost disappeared from the chromatograms. This disadvantage, which was not observed when only acid methanolysis was used, could be overcome with trifluoroacetylation. Restored peak shape of the underivatized alcohols could be achieved by washing the cross-linked stationary phase in the capillary tubing with organic solvents. The study demonstrated the importance of conditions which enable separation of 2-octadecanol and 2-eicosanol when gas chromatography is used for species identification of mycobacteria.

  14. The Construction of Scrub in California and the Mediterranean Borderlands: Climatic and Edaphic Climax Mosaic or Anthropogenic Artifact?

    NASA Astrophysics Data System (ADS)

    Rodrigue, C. M.

    2004-12-01

    There is a marked difference in the representation of Mediterranean scrub vegetation (e.g., chaparral, maquis) in North American and European literature in biogeography and ecology. Authors discussing this vegetation in the California context accept that it is a natural response to the Mediterranean climates, with their late summer and fall fires, and steep terrain. Debate here focusses on the extent to which humans have modified or, indeed, can modify "natural" fire regimes. European authors frame this vegetation instead as a secondary successional formation in a landscape that "should" be dominated by oak woodland and forest. The widespread presence of Mediterranean scrub is cast as an artifact of human disturbance over thousands of years, mediated through overgrazing, deforestation, accelerated erosion, and anthropogenic fire. This poster will present a content analysis of the Mediterranean scrub literature, in order to engage both traditions in the construction of a unified framework for these pyrogenic formations.

  15. Western scrub-jays do not appear to attend to functionality in Aesop’s Fable experiments

    PubMed Central

    Harvey, Brigit D.; Schlinger, Barney A.; Rensel, Michelle

    2016-01-01

    Western scrub-jays are known for their highly discriminatory and flexible behaviors in a caching (food storing) context. However, it is unknown whether their cognitive abilities are restricted to a caching context. To explore this question, we tested scrub-jays in a non-caching context using the Aesop’s Fable paradigm, where a partially filled tube of water contains a floating food reward and objects must be inserted to displace the water and bring the food within reach. We tested four birds, but only two learned to drop stones proficiently. Of these, one bird participated in 4/5 experiments and one in 2/5 experiments. Both birds passed one experiment, but without attending to the functional differences of the objects, and failed the other experiments. Scrub-jays were not motivated to participate in these experiments, suggesting that either this paradigm was ecologically irrelevant or perhaps their flexibility is restricted to a caching context. PMID:26925331

  16. Alkyl substituent effects on gas-phase acidities - The influence of hybridization.

    NASA Technical Reports Server (NTRS)

    Brauman, J. I.; Blair, L. K.

    1971-01-01

    Exploration of the effect on acidity of alkyl groups bonded to trigonal and digonal carbon. Some results on the relative acidities of toluene and p-xylene, and acetylene and substitute acetylenes, as determined by ion cyclotron resonance (icr) spectroscopy, are described. Some limitations of the CNDO/2 calculation method are discussed.

  17. Comparison of two derivatization methods for the analysis of fatty acids and trans fatty acids in bakery products using gas chromatography.

    PubMed

    Salimon, Jumat; Omar, Talal A; Salih, Nadia

    2014-01-01

    Two different procedures for the methylation of fatty acids (FAs) and trans fatty acids (TFAs) in food fats were compared using gas chromatography (GC-FID). The base-catalyzed followed by an acid-catalyzed method (KOCH3/HCl) and the base-catalyzed followed by (trimethylsilyl)diazomethane (TMS-DM) method were used to prepare FA methyl esters (FAMEs) from lipids extracted from food products. In general, both methods were suitable for the determination of cis/trans FAs. The correlation coefficients (r) between the methods were relatively small (ranging from 0.86 to 0.99) and had a high level of agreement for the most abundant FAs. The significant differences (P = 0.05) can be observed for unsaturated FAs (UFAs), specifically for TFAs. The results from the KOCH3/HCl method showed the lowest recovery values (%R) and higher variation (from 84% to 112%), especially for UFAs. The TMS-DM method had higher R values, less variation (from 90% to 106%), and more balance between variation and %RSD values in intraday and interday measurements (less than 4% and 6%, resp.) than the KOCH3/HCl method, except for C12:0, C14:0, and C18:0. Nevertheless, the KOCH3/HCl method required shorter time and was less expensive than the TMS-DM method which is more convenient for an accurate and thorough analysis of rich cis/trans UFA samples.

  18. /sup 57/Co-soap assay for plasma total non-esterified fatty acids compared with a gas-liquid chromatographic method

    SciTech Connect

    Turnell, D.C.; Price, C.P.; France, M.M.

    1980-12-01

    A relatively rapid radiochemical assay for determining plasma non-esterified fatty acids is described. Results correlated well with those by gas-liquid chromatography. The between-batch CV for 1.12 mmol of non-esterified fatty acids per liter was 7%.

  19. Exploring the Ideal Gas Law through a Quantitative Gasometric Analysis of Nitrogen Produced by the Reaction of Sodium Nitrite with Sulfamic Acid

    ERIC Educational Resources Information Center

    Yu, Anne

    2010-01-01

    The gasometric analysis of nitrogen produced in a reaction between sodium nitrite, NaNO[superscript 2], and sulfamic acid, H(NH[superscript 2])SO[superscript 3], provides an alternative to more common general chemistry experiments used to study the ideal gas law, such as the experiment in which magnesium is reacted with hydrochloric acid. This…

  20. Effects of high fire frequency in creosote bush scrub vegetation of the Mojave Desert

    USGS Publications Warehouse

    Brooks, M.L.

    2012-01-01

    Plant invasions can increase fire frequency in desert ecosystems where fires were historically infrequent. Although there are many resource management concerns associated with high frequency fire in deserts, fundamental effects on plant community characteristics remain largely unstudied. Here I describe the effects of fire frequency on creosote bush scrub vegetation in the Mojave Desert, USA. Biomass of the invasive annual grass Bromus rubens L. increased following fire, but did not increase further with additional fires. In contrast, density, cover and species richness of native perennial plants each decreased following fire and continued to decrease with subsequent fires, although not as dramatically as after the initial fire. Responses were similar 5 and 14 years post-fire, except that cover of Hymenoclea salsola Torr. & A. Gray and Achnatherum speciosa Trin. & Rupr. both increased in areas burnt once. These results suggest that control of B. rubens may be equally warranted after one, two or three fires, but revegetation of native perennial plants is most warranted following multiple fires. These results are valid within the scope of this study, which is defined as relatively short term vegetation responses (???14 years) to short fire return intervals (6.3 and 7.3 years for the two and three fire frequency levels) within creosote bush scrub of the Mojave Desert. ?? 2012 IAWF.

  1. Do postfire mulching treatments affect plant community recovery in California coastal sage scrub lands?

    PubMed

    McCullough, Sarah A; Endress, Bryan A

    2012-01-01

    In recent years, the use of postfire mulch treatments to stabilize slopes and reduce soil erosion in shrubland ecosystems has increased; however, the potential effects on plant recovery have not been examined. To evaluate the effects of mulching treatments on postfire plant recovery in southern California coastal sage scrub, we conducted a field experiment with three experimental treatments, consisting of two hydromulch products and an erosion control blanket, plus a control treatment. The area burned in 2007, and treatments were applied to six plot blocks before the 2008 growing season. Treatment effects on plant community recovery were analyzed with a mixed effects ANOVA analysis using a univariate repeated measures approach. Absolute plant cover increased from 13 to 90% by the end of the second growing season, and the mean relative cover of exotic species was 32%. The two hydromulch treatments had no effect on any plant community recovery response variable measured. For the erosion control blanket treatment, the amount of bare ground cover at the end of the second growing season was significantly lower (P = 0.01), and greater shrub height was observed (P < 0.01). We conclude that postfire mulch treatments did not provide either a major benefit or negative impact to coastal sage scrub recovery on the study area.

  2. Septisol antiseptic foam: a sensible alternative to the conventional surgical scrub.

    PubMed

    Rubio, P A

    1987-01-01

    Over a recent 8-year period, Septisol Foam (0.23% hexachlorophene in a 46% ethyl alcohol base) alone was used to prepare the hands and forearms of the author's surgical team. In 3480 cases, only 11 postoperative infections were encountered, for an incidence of 0.3%. All 11 infections involved patients who underwent gastrointestinal surgery and/or who had high-risk factors such as cancer, hypertension, diabetes mellitus, perforated appendix, emergency surgery, age over 65 years, and foreign bodies in the form of hemodialysis access shunts. Septisol Foam is an effective bacteriostatic agent that minimizes the risk of dermatitis and offers sufficient antibacterial protection without supplementary handwashing. When used according to the method described here, the foam eliminates the need for scrub brushes and reduces the total scrub time to approximately 2 minutes in each case. In addition to being safe, effective, and easy to use, this method results in a marked decrease in water consumption and considerable monetary savings.

  3. Hint-seeking behaviour of western scrub-jays in a metacognition task.

    PubMed

    Watanabe, Arii; Clayton, Nicola S

    2016-01-01

    Metacognitive processes during memory retrieval can be tested by examining whether or not animals can assess their knowledge state when they are faced with a memory test. In a typical foraging task, food is hidden in one of the multiple tubes and the subjects are given an opportunity to check the contents of the tubes before choosing the one that they thought contained food. Following the findings from our previous study that western scrub-jays (Aphelocoma californica) can make prospective metacognition judgements, this study tested the scrub-jays' concurrent metacognition judgements. In a series of experiments, uncertainty about the food location was induced in three ways: by making the baiting process visibly unavailable, by inserting a delay between the baiting and food retrieval, and by moving the location of the bait. The jays looked into the tubes more often during the conditions that were consistent with high uncertainty. In addition, their looking behaviour was associated not with the sight of food but with information about the location of the food. These findings suggest that the jays can differentiate the states of knowing and not knowing about certain information and take appropriate action to complement their missing knowledge.

  4. Differences in attentional strategies by novice and experienced operating theatre scrub nurses.

    PubMed

    Koh, Ranieri Y I; Park, Taezoon; Wickens, Christopher D; Ong, Lay Teng; Chia, Soon Noi

    2011-09-01

    This study investigated the effect of nursing experience on attention allocation and task performance during surgery. The prevention of cases of retained foreign bodies after surgery typically depends on scrub nurses, who are responsible for performing multiple tasks that impose heavy demands on the nurses' cognitive resources. However, the relationship between the level of experiences and attention allocation strategies has not been extensively studied. Eye movement data were collected from 10 novice and 10 experienced scrub nurses in the operating theater for caesarean section surgeries. Visual scanning data, analyzed by dividing the workstation into four main areas and the surgery into four stages, were compared to the optimum expected value estimated by SEEV (Salience, Effort, Expectancy, and Value) model. Both experienced and novice nurses showed significant correlations to the optimal percentage dwell time values, and significant differences were found in attention allocation optimality between experienced and novice nurses, with experienced nurses adhering significantly more to the optimal in the stages of high workload. Experienced nurses spent less time on the final count and encountered fewer interruptions during the count than novices indicating better performance in task management, whereas novice nurses switched attention between areas of interest more than experienced nurses. The results provide empirical evidence of a relationship between the application of optimal visual attention management strategies and performance, opening up possibilities to the development of visual attention and interruption training for better performance. PMID:21942313

  5. Determination of Scrub typhus Suggests a New Epidemic Focus in the Anhui Province of China

    PubMed Central

    Cao, Min; Che, Li; Zhang, Jinhai; Hu, Jianli; Srinivas, Swaminath; Xu, Ruiyao; Guo, Henbing; Zhang, Yun; Wang, Changjun; Feng, Youjun

    2016-01-01

    In 2007, 19 cases of a scrub typhus epidemic occurred within a week at a sports school in Mingguang County, Anhui Province, where no previous incidence of this mite borne disease had been reported. Sero-surveillance in 2009 indicated that 10 of the 100 school students possessed anti-Orientia tsutsugamushi antibodies. From 2009 to 2013, 60 small animals and 2250 mites were collected in the vicinity of the school. 5 of the Apodemus agrarius samples and 1 group of Leptotrombidium linhuaikongense tested positive via PCR for O. tsutsugamushi. Two strains of O. tsutsugamushi were identified by injecting Kun Ming (KM) mice peritoneally with the organs of either Apodemus agrarius or Leptotrombidium linhuaikongense. Apart from sharing 98% homology with the O. tsutsugamushi Yongworl strain, genes encoding the membrane protein from the two O. tsutsugamushi isolates shared >99% sequence homology with each other, reflecting the consistency of the pathogen in both the vector and the host. In addition, we also characterized a chronic scrub typhus infection in a local patient. The membrane protein gene fragment from the patient’s blood shared 99% homology with O. tsutsugamushi Gilliam strain, suggesting that more than one O. tsutsugamushi strain is present at this location. PMID:26860982

  6. Parameterization of albedo, thermal inertia, and surface roughness of desert scrub/sandy soil surface

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Mccumber, M.

    1986-01-01

    Spectral albedo, A sub n, for the direct solar beam is defined as A sub n (r sub i,s, theta sub 0) = r sub i exp(-s tan theta sub 0)1-I(s) where I(s) is the integral over all reflection angles describing the interception by the absorbing plants of the flux reflected from the soil, r sub i soil reflectance, assumed Lambertian, S the projection on a vertical plane of plants per unit surface area, and theta sub 0 is the solar zenith angle. Hemispheric reflectance for the direct solar beam equals 1-I(s) times the reflectance to the zenith. The values of s of 0.1, 0.2, and 0.3 respectively quantify sparse, moderately dense, and very dense desert scrub. Thin plants are assumed to be of negligible thermal inertia, and thus directly yield the absorbed insolation to the atmosphere. Surface thermal inertia is therefore effectively reduced. The ratio of surface roughness height to plant height is parameterized for sparse, moderately dense, and very dense desert-scrub as a function of s based on data expressing the dependence of this ratio on plant silhouette.

  7. Optimizing the order of operations for movement scrubbing: Comment on Power et al.

    PubMed

    Carp, Joshua

    2013-08-01

    A recent study by Power and colleagues shows that BOLD artifacts induced by head movement can substantially alter patterns of resting-state functional connectivity and proposes a novel procedure for reducing these artifacts by deleting (or "scrubbing") movement-contaminated volumes. The authors acknowledge that this work is descriptive and not prescriptive, and note that future studies may refine the proposed scrubbing method. Nevertheless, it is worth pointing out that this method can be improved substantially by a single transposition in the order of operations. Temporal filtering is known to introduce ringing artifacts that emanate from sharp transitions in signal intensity. The method proposed in the target article applies temporal filtering before deleting contaminated volumes-in effect, spreading movement-related artifacts backwards and forwards in time, but deleting only the originally contaminated data. Using simulated data, we show that deleting and replacing contaminated volumes before temporal filtering removes a greater proportion of artifactual signal while retaining a greater proportion of the original data.

  8. Vegetation recovery following high-intensity wildfire and silvicultural treatments in sand pine scrub

    SciTech Connect

    Greenberg, C.H.; Neary, D.G.; Harris, L.D.; Linda, S.P.

    1995-12-31

    The authors hypothesized that clear-cutting mimics natural high-intensity disturbance by wildfire followed by salvage logging in sand pine scrub, and tested whether vegetation adapted to recovery from fire would respond similarly to another type of biomass removal. The authors measured plant community composition and structural characteristics in three replicated disturbance treatments and in mature sand pine forest (MF). Treatments were: (1) high-intensity burn, salvage logged and naturally regenerated (HIBS); (2) clear-cut, roller-chopped, and broadcast-seeded (RC); and (3) clear-cut and bracke-seeded (BK). All treatments were sampled 5-7 yr postdisturbance. Nonwoody plant species richness and diversity were significantly lower in MF than in disturbance treatments. Ruderal species were more abundant in HIBS and RC, but not to the exclusion of the characteristic suite of native scrub species. Shrub richness and diversity did not differ, but some species responded differently among treatments. Differences may be due to season of disturbance or rhizome depth.

  9. California Wildlife Habitat Relationships System: A test in coastal scrub and annual grassland habitats

    USGS Publications Warehouse

    Howell, J.A.; Barrett, R.H.

    1998-01-01

    We tested predictions of the California Wildlife Habitat Relationships (CWHR) System in coastal scrub and annual grassland. We detected a total of 28 species of terrestrial vertebrates: 18 mammals, 9 reptiles, and 1 amphibian. The CWHR System prediction omitted 4 of these species: 3 domestic mammals and 1 reptile. For the 2 habitats combined, CWHR predicted a total of 38 species: 23 mammals, 13 reptiles, and 2 amphibians. We detected 64% of these predicted grassland species and 71% of predicted coastal scrub species. For the habitats combined, we detected 65% of the species predicted to be present by the CWHR System. We detected 68% of the mammals, 62% of the reptiles, and 50% of the amphibians predicted for these habitats. The CWHR System theoretically predicts absence rather than presence, since it is assumed that all 288 regularly occurring mammals, reptiles, and amphibians occur anywhere unless one can argue that a specific habitat, location, or habitat element is not available. By including predictions of species absence in the assessment of model performance, observed accuracy of the CWHR model predictions increased to 96% for both habitats.

  10. A Case of Scrub Typhus Complicated by Adult Respiratory Distress Syndrome and Successful Management with Extracorporeal Membrane Oxygenation.

    PubMed

    Choi, Woo Young; Lee, Seung Yun; Kwon, Hea Yoon; Im, Jae Hyoung; Durey, Areum; Baek, Ji Hyeon; Kim, Young Sam; Kang, Jae-Seung; Lee, Jin-Soo

    2016-09-01

    A 67-year-old woman was diagnosed as having scrub typhus with pneumonitis. On admission, she was started on a combination therapy with levofloxacin and doxycycline. However, the patient developed severe acute respiratory distress syndrome (ARDS) on the 2nd day, and as a result, she underwent extracorporeal membrane oxygenation (ECMO). She was weaned from ECMO on the 10th day, as her respiratory status gradually improved. She was discharged without sequelae on the 23rd day. The outcome suggests that the use of ECMO should be considered for patients with ARDS induced from scrub typhus. PMID:27458040

  11. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  12. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  13. Gas-liquid chromatographic detection an determination of diacetyl tartaric acid ester of diglyceride in dairy and nondairy coffee cream powders.

    PubMed

    Inoue, T; Iwaida, M; Ito, Y; Tonogai, Y

    1981-03-01

    Diacetyl tartaric acid ester of diglyceride was directly extracted from dairy or nondairy coffee cream powder under acidic conditions with ethyl acetate; then the extract was saponified with methanolic potash. After acidification with HCl, free fatty acid was removed with ether and the reaction mixture was absorbed on an anion exchange column. Tartaric acid was eluted with 2N HCl-acetone (1+1). An aliquot of the trimethylsilyl (TMS) derivative of the eluate was injected into a gas chromatograph with flame ionization detection, and a 1.5% SE-30 column. Recoveries of diacetyl tartaric acid ester of diglyceride at 50, 200, and 2000 ppm were 85.6-99.5%.

  14. Reexamination of CO formation during formic acid decomposition on the Pt(1 1 1) surface in the gas phase

    NASA Astrophysics Data System (ADS)

    Wang, Yingying; Zhang, Dongju; Liu, Peng; Liu, Chengbu

    2016-08-01

    Existing theoretical results for formic acid (HCOOH) decomposition on Pt(1 1 1) cannot rationalize the easy CO poisoning of the catalysts in the gas phase. The present work reexamined HCOOH decomposition on Pt(1 1 1) by considering the effect of the initial adsorption structure of the reactant on the reactivity. Our calculations present a new adsorption configuration of HCOOH on Pt(1 1 1), from which the formation of CO is found to be competing with the formation of CO2. The newly proposed mechanism improves our understanding for the mechanism of HCOOH decomposition catalyzed by Pt-based catalysts.

  15. Gas chromatographic and mass spectrometric determination of chlorophenoxy acids and related herbicides as their (cyanoethyl)dimethylsilyl derivatives

    SciTech Connect

    Bertrand, M.J.; Ahmed, A.W.; Sarrasin, B.; Mallet, V.N.

    1987-05-01

    A method for using (2-cyanoethyl)dimethyl(diethylamino)silane to form derivatives with phenoxy acid herbicides and related compounds is presented. Results obtained with 18 compounds demonstrate that the reaction is quantitative and complete within minutes at room temperature. The derivatives formed can readily be analyzed by gas chromatography using a selective nitrogen-phosphorus detector which eliminates the need for rigorous cleanup of the sample required for detection by electron capture. Response-concentration plots show that detection is linear over several decades with limits of detection being in the low picogram range for all compounds studied. Mass spectral analysis of the derivatives of the 18 compounds studied indicates that the spectra are highly specific showing characteristic ions at (M-54), (M-82), and or (M-98) which are useful for structure confirmation or analysis at low levels by using selected ion monitoring. The analytical advantages of the approach for the analysis of acid herbicides are discussed.

  16. Excitonic splitting and coherent electronic energy transfer in the gas-phase benzoic acid dimer

    SciTech Connect

    Ottiger, Philipp; Leutwyler, Samuel

    2012-11-28

    The benzoic acid dimer, (BZA){sub 2}, is a paradigmatic symmetric hydrogen bonded dimer with two strong antiparallel hydrogen bonds. The excitonic S{sub 1}/S{sub 2} state splitting and coherent electronic energy transfer within supersonically cooled (BZA){sub 2} and its {sup 13}C-, d{sub 1}-, d{sub 2}-, and {sup 13}C/d{sub 1}- isotopomers have been investigated by mass-resolved two-color resonant two-photon ionization spectroscopy. The (BZA){sub 2}-(h-h) and (BZA){sub 2}-(d-d) dimers are C{sub 2h} symmetric, hence only the S{sub 2} Leftwards-Arrow S{sub 0} transition can be observed, the S{sub 1} Leftwards-Arrow S{sub 0} transition being strictly electric-dipole forbidden. A single {sup 12}C/{sup 13}C or H/D isotopic substitution reduces the symmetry of the dimer to C{sub s}, so that the isotopic heterodimers (BZA){sub 2}-{sup 13}C, (BZA){sub 2}-(h-d), (BZA){sub 2}-(h{sup 13}C-d), and (BZA){sub 2}-(h-d{sup 13}C) show both S{sub 1} Leftwards-Arrow S{sub 0} and S{sub 2} Leftwards-Arrow S{sub 0} bands. The S{sub 1}/S{sub 2} exciton splitting inferred is {Delta}{sub exc}= 0.94 {+-} 0.1 cm{sup -1}. This is the smallest splitting observed so far for any H-bonded gas-phase dimer. Additional isotope-dependent contributions to the splittings, {Delta}{sub iso}, arise from the change of the zero-point vibrational energy upon electronic excitation and range from {Delta}{sub iso}= 3.3 cm{sup -1} upon {sup 12}C/{sup 13}C substitution to 14.8 cm{sup -1} for carboxy H/D substitution. The degree of excitonic localization/delocalization can be sensitively measured via the relative intensities of the S{sub 1} Leftwards-Arrow S{sub 0} and S{sub 2} Leftwards-Arrow S{sub 0} origin bands; near-complete localization is observed even for a single {sup 12}C/{sup 13}C substitution. The S{sub 1}/ S{sub 2} energy gap of (BZA){sub 2} is {Delta}{sub calc}{sup exc}=11 cm{sup -1} when calculated by the approximate second-order perturbation theory (CC2) method. Upon correction for vibronic

  17. Implications of the Clean Air Act acid rain title on industrial boilers

    SciTech Connect

    Maibodi, M. )

    1991-11-01

    This paper discusses the impacts of the 1990 Clean Air Act Amendments related to acid rain controls, as they apply to industrial boilers. Emphasis is placed on explaining the Title IV provisions of the Amendments that permit nonutility sources to participate in the SO{sub 2} allowance system. The allowance system, as it pertains to industrial boiler operators, is described, and the opportunities for operators to trade and/or sell SO{sub 2} emission credits is discussed. The paper also reviews flue gas desulfurization system technologies available for industrial boiler operators who may choose to participate in the system. Furnace sorbent injection, advanced silicate process, lime spray drying, dry sorbent injection, and limestone scrubbing are described, including statements of their SO{sub 2} removing capability, commercial status, and costs. Capital costs, levelized costs and cost-effectiveness are presented for these technologies.

  18. Gas-particle partitioning of organic acids during the Southern Oxidant and Aerosol Study (SOAS): measurements and modeling

    NASA Astrophysics Data System (ADS)

    Thompson, S.; Yatavelli, R.; Stark, H.; Kimmel, J.; Krechmer, J.; Day, D. A.; Isaacman, G. A.; Goldstein, A. H.; Khan, M. A. H.; Holzinger, R.; Lopez-Hilfiker, F.; Mohr, C.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2014-12-01

    Gas-Particle partitioning measurements of organic acids were carried out during the Southern Oxidant and Aerosol Study (SOAS, June-July 2013) at the Centerville, AL Supersite in the Southeast US, a region with significant isoprene and terpene emissions. Organic acid measurements were made with a Chemical Ionization High Resolution Time-of-Flight Mass Spectrometer (HRToF-CIMS) with a Filter Inlet for Gases and AEROsols (FIGAERO) and acetate (CH3COO-) as the reagent ion. We investigate both individual species and bulk organic acids and partitioning to organic and water phases in the aerosol. Measured partitioning is compared to data from three other instruments that can also quantify gas-particle partitioning with high time resolution: another HRToF-CIMS using iodide (I-) as the reagent ion to ionize acids and other highly oxidized compounds, a Semivolatile Thermal Desorption Aerosol GC/MS (SV-TAG), and a Thermal Desorption Proton Transfer Time-of-Flight Mass Spectrometer (TD-PTRMS The partitioning measurements for three of the instruments are generally consistent, with results in the same range for most species and following similar temporal trends and diurnal cycles. The TD-PTRMS measures on average ½ the partitioning to the particle phase of the acetate CIMS. Both the measurements and the model of partitioning to the organic phase respond quickly to temperature, and the model agrees with the measured partitioning within the error of the measurement for multiple compounds, although many compounds do not match the modeled partitioning, especially at lower m/z. This discrepancy may be due to thermal decomposition of larger molecules into smaller ones when heated.

  19. Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses

    PubMed Central

    da Silveira, Eduardo Almeida; Bubeck, Kirstin A.; Batista, Edisleidy Rodriguez; Piat, Perrine; Laverty, Sheila; Beauchamp, Guy; Archambault, Marie; Elce, Yvonne

    2016-01-01

    This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing technique, and after surgery. There was no significant difference in mean bacterial colony forming units between scrub and rub techniques over the 3 time periods (P = 0.6), controlling for initial counts. One horse from the scrub group had a skin incision infection following stifle arthroscopy; this was resolved with medical treatment. The alcohol-based hand rub is equivalent in efficacy for pre-surgical hand antisepsis to traditional water-based scrubs in an equine hospital setting. PMID:26834268

  20. Comparison of an alcohol-based hand rub and water-based chlorhexidine gluconate scrub technique for hand antisepsis prior to elective surgery in horses.

    PubMed

    da Silveira, Eduardo Almeida; Bubeck, Kirstin A; Batista, Edisleidy Rodriguez; Piat, Perrine; Laverty, Sheila; Beauchamp, Guy; Archambault, Marie; Elce, Yvonne

    2016-02-01

    This prospective clinical study evaluates the effectiveness of an alcohol-based hand rub (Avagard™) for pre-surgical hand antisepsis in an equine hospital and compares it with traditional scrubbing technique using 4% chlorhexidine gluconate sponges and water. Prior to elective surgery, 3 board-certified surgeons were randomly assigned to hand antisepsis with either technique. Culture samples of each hand were taken at 4 times: before and after neutral soap hand wash, after scrub or rubbing technique, and after surgery. There was no significant difference in mean bacterial colony forming units between scrub and rub techniques over the 3 time periods (P = 0.6), controlling for initial counts. One horse from the scrub group had a skin incision infection following stifle arthroscopy; this was resolved with medical treatment. The alcohol-based hand rub is equivalent in efficacy for pre-surgical hand antisepsis to traditional water-based scrubs in an equine hospital setting. PMID:26834268

  1. Determination of underivatised sterols and bile acid trimethyl silyl ether methyl esters by gas chromatography-mass spectrometry-single ion monitoring in faeces.

    PubMed

    Keller, Sylvia; Jahreis, Gerhard

    2004-12-25

    A method for quantification of total faecal sterols and bile acids (BAs) in human stool by using gas chromatography-mass spectrometry-single ion monitoring (GC-MS-SIM) is described. Cholesterol, coprostanol, coprostanone, cholestanol, iso-lithocholic acid (iso-LCA), lithocholic acid (LCA), iso-deoxycholic acid (iso-DCA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), cholic acid (CA), and 12-oxo-deoxycholic acid (12-oxo-DCA) in faeces of 86 healthy subjects were determined. The sample preparation for sterol analysis requires hydrolysis and liquid extraction from matrix, but no derivatisation. The GC-flame ionisation detection (FID) and total ion current (TIC) in GC-MS were not sufficient for sterol and BA determination, whereas selectivity and specificity of the GC-MS-SIM ensured the analysis of sterols and BAs in faeces. PMID:15556534

  2. Kinetics of gas phase formic acid decomposition on platinum single crystal and polycrystalline surfaces

    NASA Astrophysics Data System (ADS)

    Detwiler, Michael D.; Milligan, Cory A.; Zemlyanov, Dmitry Y.; Delgass, W. Nicholas; Ribeiro, Fabio H.

    2016-06-01

    Formic acid dehydrogenation turnover rates (TORs) were measured on Pt(111), Pt(100), and polycrystalline Pt foil surfaces at a total pressure of 800 Torr between 413 and 513 K in a batch reactor connected to an ultra-high vacuum (UHV) system. The TORs, apparent activation energies, and reaction orders are not sensitive to the structure of the Pt surface, within the precision of the measurements. CO introduced into the batch reactor depressed the formic acid dehydrogenation TOR and increased the reaction's apparent activation energies on Pt(111) and Pt(100), consistent with behavior predicted by the Temkin equation. Two reaction mechanisms were explored which explain the formic acid decomposition mechanism on Pt, both of which include dissociative adsorption of formic acid, rate limiting formate decomposition, and quasi-equilibrated hydrogen recombination and CO adsorption. No evidence was found that catalytic supports used in previous studies altered the reaction kinetics or mechanism.

  3. Gas chromatography/trace analysis of derivatized azelaic acid as a stability marker.

    PubMed

    Alzweiri, Muhammed; Tarawneh, Ruba; Khanfar, Mohammad A

    2013-10-01

    Azelaic acid, a naturally occurring saturated dicarboxylic acid, is found in many topical formulations for its various medical benefits or as a byproduct of the oxidative decomposition of unsaturated fatty acids. The poor volatility of azelaic acid hinders its applicability in GC analysis. Therefore, azelaic acid was derivatized by methylation and silylation procedures to enhance its volatility for GC analysis. Accordingly, dimethyl azelate (DMA) and di(trimethylsilyl) azelate were synthesized and characterized by GC-MS. Subsequently, a GC with flame ionization detection method was developed and validated to analyze trace amounts of azelaic acid in some marketed skin creams. Unlike DMA, di(trimethylsilyl) azelate was chemically unstable and degraded within few hours. Nonane was used as a stable internal standard. Variability due to derivatization and extraction was controlled by a standard addition procedure. DMA analysis was linear in a wide concentration range (100 ng/mL to 100 mg/mL). Moreover, the method was accurate (96.4-103.4%) and precise with inter- and intraday variability <2.0% and LOQ and LOD of 100 and 10 ng/mL, respectively. PMID:23893928

  4. Naphthenic acids inhibit root water transport, gas exchange and leaf growth in aspen (Populus tremuloides) seedlings.

    PubMed

    Kamaluddin, M; Zwiazek, Janusz J

    2002-12-01

    Effects of sodium naphthenates (NAs) on root hydraulic conductivity (Lp) and gas exchange processes were examined in aspen (Populus tremuloides Michx.) seedlings grown in solution culture. Exposure of roots to NAs for 3-5 weeks significantly decreased Lp and stomatal conductance. Root-absorbed NAs also decreased leaf chlorophyll concentration, net photosynthesis and leaf growth. Short-term (< or = 2 h) exposure of excised roots to NAs significantly decreased root water flow (Qv) with a concomitant decline in root respiration. We conclude that NAs metabolically inhibited Lp, likely by affecting water channel activity, and that this inhibition could be responsible for the observed reductions in gas exchange and leaf growth.

  5. Acid gas treating by aqueous alkanolamines. Annual report, January-December 1993

    SciTech Connect

    Sandall, O.C.; Rinker, E.B.; Ashour, S.

    1993-12-01

    The objective of the work is to investigate the simultaneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed thus far, density, viscosity, gas diffusivity, gas solubility, surface tension, and amine solution vapor pressure have been measured for aqueous MDEA, DEA, and MDEA/DEA mixtures over the temperature range 20 to 100 deg. C and for concentrations up to 50 weight %. A mathematical model, based on the penetration theory, for the simultaneous absorption (desorption) of CO2 and H2S into (from) aqueous solutions of MDEA and DEA has been developed.

  6. Reclamation of elemental sulfur from flue gas biodesulfurization waste sludge.

    PubMed

    Wang, Chengwen; Wang, Yujue; Zhang, Yanqi; Zhao, Qi; Wang, Ran

    2010-05-01

    Perchloroethylene (PCE) extraction was used to reclaim elemental sulfur from flue gas biodesulfurization sludge. The sludge was generated from a biodesulfurization system that concurrently treated the flue gas scrubbing solution and wastewater of citric acid production. The sludge contained approximately 40-60% elemental sulfur; other components included flue gas dust, biomass, inorganic salts, and flocculants. The sulfur was extracted with PCE at 80 degrees C, and then separated from the sludge by hot filtration. The elemental sulfur was then recovered from the PCE solution by recrystallization and centrifugation. When the dried sludge with particle size less than 0.2 mm was used in the PCE extraction, more than 90% of the elemental sulfur in the sludge could be recovered with a contact time of 15 min and a PCE-to-sludge ratio of 5 mL PCE/g sludge. The recovered sulfur generally had purities of 98-99.9% and could be directly used in many industries. Reuse of the PCE solvent in the extraction protocol through four cycles did not adversely influence the sulfur recovery efficiency. The results indicated that the PCE extraction was an effective method for the sulfur recovery from the biodesulfurization sludge.

  7. Greenhouse gas reduction and improved sustainability of animal husbandry using amino acids in swine, poultry feeds.

    PubMed

    Tsujimoto, Susumu; Takagi, Tomo; Osada, Takashi; Ogino, Akifumi

    2013-05-01

    In Annex 1 countries, nitrous oxide (N2 O) emissions from swine and poultry excreta have been calculated and the N2 O reduction potential of each country by using amino acids in feed could also be calculated, then a comparison made among the countries. The N2 O reduction rates were approximately 25% for these Annex 1 countries and amino acids were able to make a large contribution to that reduction. Greenhouse gases (GHG) which are N2 O combined with methane (CH4 ) were estimated to reduce by 24.8% in Japan when amino acids were introduced into the feed, but only a 7.2% reduction was estimated in France. Purification, which is mainly used for manure treatment in Japan, emits much more N2 O and less CH4 , whereas the liquid system which is mainly used in France emits more CH4 and less N2 O based on the emission factors from the United Nations Framework Convention on Climate Change data base. Changing the French manure treatment system to the Japanese style with amino acids in feed would reduce GHG emissions by 23.4%. Reduction of the arable land use in Japan by changing crop formulations supported by adding amino acids to feed was also quantified as about 10% and led to an increase in the production of meat using the same arable land area. PMID:23607750

  8. Effects of Anthropogenic Emissions on the Nitrogen Cycle in the Desert Creosote Scrub Ecosystem

    NASA Astrophysics Data System (ADS)

    Scanlan, J.; Simunek, J.

    2009-12-01

    Wildfires are an ongoing threat to many ecosystems in Southern California. In some ecosystems, evidence suggests that high anthropogenic nitrogen deposition can increase susceptibility to fire by increasing the fuel loads and altering the plant species composition. Desert creosote scrub ecosystems are dominant throughout many low-elevation areas in the Mohave Desert and are among the ecosystems subjected to added deposition of nitrate and ammonium due to emissions from nearby agriculture and fossil fuel combustion. An understanding of how nitrogen flows through the desert creosote scrub ecosystem and of how the additional deposition affects this cycle is critical to determining how these ecosystems will change over time and assessing how the spread of fires can be mitigated. One high deposition and one low deposition desert creosote scrub site in Joshua Tree National Park have been studied for the past year in order to observe the flow of nitrogen through the soil and assess its connection to shifts in the vegetation. Extractable nitrate, extractable ammonium, and total nitrogen and carbon have been measured throughout 100cm soil profiles at each site in order to determine the fate and transport of the deposited nitrogen. Because the flow of water through the soil following the infrequent precipitation events is essential to the flow of nitrogen, dielectric water potential sensors have been installed throughout the top 70cm of soil in order to obtain hourly measurements of water potential. These measurements have been used in conjunction with weather and deposition data to model the flow of water and nitrogen through the soil using the hydrological model HYDRUS-1D. A geochemical model representing basic nitrogen reactions occurring in the soil has been started using PHREEQC coupled with HYDRUS-1D, but further modeling is necessary in order to accurately represent the complexity of the nitrogen cycle. After completion of an additional year of measurements and

  9. Wheat dextrin, psyllium, and inulin produce distinct fermentation patterns, gas volumes, and short-chain fatty acid profiles in vitro.

    PubMed

    Timm, Derek A; Stewart, Maria L; Hospattankar, Ashok; Slavin, Joanne L

    2010-08-01

    Dietary fiber fermentation decreases luminal pH by the production of short-chain fatty acids (SCFAs). Additional proposed physiological benefits of fiber fermentation include decreased growth of pathogenic bacteria, increased mineral absorption, and serving as an energy source for the colon epithelium. This study examined three common fiber supplements--wheat dextrin (WD) (Benefiber, Novartis Consumer Health Inc., Parsippany, NJ, USA), psyllium (PS) (Metamucil, Procter & Gamble, Cincinnati, OH, USA), and inulin (Fiber Sure, Procter & Gamble)--for pH, SCFAs, and gas production. An established in vitro fermentation model was used to simulate colonic fermentation at 0, 4, 8, 12, and 24 hours. At 24 hours, WD and inulin significantly decreased pH compared to PS. Inulin produced significantly more hydrogen and total gas. All treatments produced similar total SCFA concentrations at 24 hours; however, the rate of production was different. PS had a declining rate of SCFA production from 12 to 24 hours, whereas WD and inulin had a higher rate during that period. Fast-fermenting substrates may not provide as much SCFAs to the distal colon as slow-fermenting substrates. Differences in fermentation rate, gas production, and SCFA production observed for WD, PS, and inulin may affect their gastrointestinal tolerance and require further study.

  10. Leaf-level and whole-plant gas exchange characteristics of shortleaf pine exposed to ozone and simulated acid rain.

    PubMed

    Flagler, R B; Lock, J E; Elsik, C G

    1994-04-01

    Field-grown shortleaf pine (Pinus echinata Mill.) seedlings were exposed to ozone (O(3)) and simulated acid rain (SAR) in open-top chambers over three growing seasons. Ranges of O(3) and SAR spanned ambient levels found in the southern USA. Effects of O(3) on leaf-level and whole-plant gas exchange were characterized for a single measurement period immediately before the third summer of exposure. Decreased photosynthesis rates were attributed to O(3), but not SAR. Stomatal conductance decreased in response to O(3) exposure, and either increased or was unaffected by SAR. Increased internal CO(2) concentration (c(i)) in response to O(3) treatment indicated a greater effect of O(3) on photosynthetic capacity than stomatal conductance. Whole-seedling gas exchange characteristics indicated that whole-seedling carbon assimilation was more severely affected by O(3) than was evident from leaf-level gas exchange characteristics. Seedlings exposed to O(3) retained fewer flushes than seedlings grown in charcoal-filtered air.

  11. Flue gas desulfurization: Physicochemical and biotechnological approaches

    SciTech Connect

    Pandey, R.A.; Biswas, R.; Chakrabarti, T.; Devotta, S.

    2005-07-01

    Various flue gas desulfurization processes - physicochemical, biological, and chemobiological - for the reduction of emission of SO{sub 2} with recovery of an economic by-product have been reviewed. The physicochemical processes have been categorized as 'once-through' and 'regenerable.' The prominent once-through technologies include wet and dry scrubbing. The wet scrubbing technologies include wet limestone, lime-inhibited oxidation, limestone forced oxidation, and magnesium-enhanced lime and sodium scrubbing. The dry scrubbing constitutes lime spray drying, furnace sorbent injection, economizer sorbent injection, duct sorbent injection, HYPAS sorbent injection, and circulating fluidized bed treatment process. The regenerable wet and dry processes include the Wellman Lord's process, citrate process, sodium carbonate eutectic process, magnesium oxide process, amine process, aqueous ammonia process, Berglau Forchung's process, and Shell's process. Besides these, the recently developed technologies such as the COBRA process, the OSCAR process, and the emerging biotechnological and chemobiological processes are also discussed. A detailed outline of the chemistry, the advantages and disadvantages, and the future research and development needs for each of these commercially viable processes is also discussed.

  12. Simulation of Electron Cloud Density Distributions in RHIC Dipoles at Injection and Transition and Estimates for Scrubbing Times

    SciTech Connect

    He,P.; Blaskiewicz, M.; Fischer, W.

    2009-01-02

    In this report we summarize electron-cloud simulations for the RHIC dipole regions at injection and transition to estimate if scrubbing over practical time scales at injection would reduce the electron cloud density at transition to significantly lower values. The lower electron cloud density at transition will allow for an increase in the ion intensity.

  13. delta 13C analyses of vegetable oil fatty acid components, determined by gas chromatography--combustion--isotope ratio mass spectrometry, after saponification or regiospecific hydrolysis.

    PubMed

    Woodbury, S E; Evershed, R P; Rossell, J B

    1998-05-01

    The delta 13C values of the major fatty acids of several different commercially important vegetable oils were measured by gas chromatography--combustion--isotope ratio mass spectrometry. The delta 13C values obtained were found to fall into two distinct groups, representing the C3 and C4 plants classes from which the oils were derived. The delta 13C values of the oils were measured by continuous flow elemental isotope ratio mass spectrometry and were found to be similar to their fatty acids, with slight differences between individual fatty acids. Investigations were then made into the influence on the delta 13C values of fatty acids of the position occupied on the glycerol backbone. Pancreatic lipase was employed to selectively hydrolyse fatty acids from the 1- and 3-positions with the progress of the reaction being followed by high-temperature gas chromatography in order to determine the optimum incubation time. The 2-monoacylglycerols were then isolated by thin-layer chromatography and fatty acid methyl esters prepared. The delta 13C values obtained indicate that fatty acids from any position on the glycerol backbone are isotopically identical. Thus, whilst quantification of fatty acid composition at the 2-position and measurement of delta 13C values of oils and their major fatty acids are useful criteria in edible oil purity assessment, measurement of delta 13C values of fatty acids from the 2-position does not assist with oil purity assignments.

  14. Exhaust gas clean up process

    DOEpatents

    Walker, R.J.

    1988-06-16

    A method of cleaning an exhaust gas containing particulates, SO/sub 2/ and NO/sub x/ is described. The method involves prescrubbing with water to remove HCl and most of the particulates, scrubbing with an aqueous absorbent containing a metal chelate and dissolved sulfite salt to remove NO/sub x/ and SO/sub 2/, and regenerating the absorbent solution by controlled heating, electrodialysis and carbonate salt addition. The NO/sub x/ is removed as N/sub 2/ gas or nitrogen sulfonate ions and the oxides of sulfur are removed as a valuable sulfate salt. 4 figs.

  15. Effect of Electrospray Ionization Source Conditions on the Tautomer Distribution of Deprotonated p-Hydroxybenzoic Acid in the Gas Phase.

    PubMed

    Xia, Hanxue; Attygalle, Athula B

    2016-06-01

    The deprotonation site of p-hydroxybenzoic acid upon electrospray ionization has been a subject of fervent debate in several articles in the Journal of the American Chemical Society and elsewhere. General consensus is that electrospray ionization mass spectrometry (ESI-MS) experimental results reflect the situation in solution to a considerable extent. Our research, using ion-mobility mass spectrometry, challenges the notion that ESI-MS results directly reflect solution-phase structures and demonstrates that the relative populations of the thermodynamically less favored gaseous carboxylate tautomer or the thermodynamically more favored gaseous phenoxide tautomer, generated from the same aqueous solution of p-hydroxybenzoic acid by ESI, can be varied back and forth by changing the probe position, capillary voltage, desolvation-gas temperature, sample infusion flow rate, and cone voltage. In other words, solvent effects are not the primary criteria that determine the relative population distributions of tautomeric carboxylate (C(-)) and phenoxide (P(-)) ions (m/z 137) generated by electrospray ionization of p-hydroxybenzoic acid. In addition, we propose that the observed ratio of the P(-) and C(-) forms indirectly reflects the relative contribution of the charge-residue or ion-evaporation process that occurs during the electrospray ion generation process.

  16. Comparison of two gas-liquid chromatograph columns for the analysis of fatty acids in ruminant meat.

    PubMed

    Alves, Susana P; Bessa, Rui J B

    2009-06-26

    Two gas-liquid chromatograph capillary columns for the analysis of fatty acids (FA) in ruminant fat are compared. Those columns are the CP-Sil 88 of 100 m long with a highly polar stationary phase and the Omegawax 250 of 30 m long with a stationary phase of intermediate polarity. Fatty acid methyl ester (FAME) patterns of branched-chain, cis and trans octadecenoate isomers, as well as conjugated and non-conjugated 18:2 and 18:3 isomers are fairly different between columns, even though most of the FAME could be separated on either column. However, the CP-Sil 88 showed better resolution of 18:1 isomers than Omegawax 250. The analysis of 96 samples of ruminant meat fat in both chromatographic systems showed that averages obtained for total FA content and for most of the individual FA did not differ between columns. Moreover, regression analysis of Omegawax and CP-Sil 88 data is highly correlated. Quantitative differences between chromatographic systems were detected for samples containing more than 66 mg fatty acids per gram of muscle dry matter.

  17. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    PubMed

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)). PMID:22907042

  18. Profiling fatty acids in vegetable oils by reactive pyrolysis-gas chromatography with dimethyl carbonate and titanium silicate.

    PubMed

    Fabbri, Daniele; Baravelli, Valentina; Chiavari, Giuseppe; Prati, Silvia

    2005-12-30

    A novel methodology in on-line pyrolysis-gas chromatography (Py-GC) for the fast analysis of fatty acids in vegetable oils with minimal sample treatment and the use of non-toxic reagents is described. Pyrolysis at 500 degrees C for 10 s of sub-microgram quantity of vegetable oil dissolved in dimethyl carbonate (DMC) and in the presence of nanopowder titanium silicon oxide resulted in the production of fatty acid methyl esters (FAMEs) as unique products. Pyrolysis performed by means of a resistively heated filament pyrolyser interfaced to a GC-MS apparatus enabled the direct analysis of evolved FAMEs. The DMC/Py-GC-MS analysis was tested on soybean, coconut, linseed, walnut and olive oil and the results compared to the classical BF(3)-methanol as reference methodology. The DMC method exhibited a lower precision and was biased towards lower levels of polyunsaturated fatty acids (PUFA) in comparison to the BF(3)-methanol method, but was more advantageous in terms of reduced sample treatment, waste generation and risk factors of employed chemicals.

  19. An experimental and computational investigation into the gas-phase acidities of tyrosine and phenylalanine: three structures for deprotonated tyrosine.

    PubMed

    Bokatzian, Samantha S; Stover, Michele L; Plummer, Chelsea E; Dixon, David A; Cassady, Carolyn J

    2014-11-01

    Using mass spectrometry and correlated molecular orbital theory, three deprotonated structures were revealed for the amino acid tyrosine. The structures were distinguished experimentally by ion/molecule reactions involving proton transfer and trimethylsilyl azide. Gas-phase acidities from proton transfer reactions and from G3(MP2) calculations generally agree well. The lowest energy structure, which was only observed experimentally using electrospray ionization from aprotic solvents, is deprotonated at the carboxylic acid group and is predicted to be highly folded. A second unfolded carboxylate structure is several kcal/mol higher in energy and primarily forms from protic solvents. Protic solvents also yield a structure deprotonated at the phenolic side chain, which experiments find to be intermediate in energy to the two carboxylate forms. G3(MP2) calculations indicate that the three structures differ in energy by only 2.5 kcal/mol, yet they are readily distinguished experimentally. Structural abundance ratios are dependent upon experimental conditions, including the solvent and accumulation time of ions in a hexapole. Under some conditions, carboxylate ions may convert to phenolate ions. For phenylalanine, which lacks a phenolic group, only one deprotonated structure was observed experimentally when electrosprayed from protic solvent. This agrees with G3(MP2) calculations that find the folded and unfolded carboxylate forms to differ by 0.3 kcal/mol.

  20. Effect of Electrospray Ionization Source Conditions on the Tautomer Distribution of Deprotonated p-Hydroxybenzoic Acid in the Gas Phase.

    PubMed

    Xia, Hanxue; Attygalle, Athula B

    2016-06-01

    The deprotonation site of p-hydroxybenzoic acid upon electrospray ionization has been a subject of fervent debate in several articles in the Journal of the American Chemical Society and elsewhere. General consensus is that electrospray ionization mass spectrometry (ESI-MS) experimental results reflect the situation in solution to a considerable extent. Our research, using ion-mobility mass spectrometry, challenges the notion that ESI-MS results directly reflect solution-phase structures and demonstrates that the relative populations of the thermodynamically less favored gaseous carboxylate tautomer or the thermodynamically more favored gaseous phenoxide tautomer, generated from the same aqueous solution of p-hydroxybenzoic acid by ESI, can be varied back and forth by changing the probe position, capillary voltage, desolvation-gas temperature, sample infusion flow rate, and cone voltage. In other words, solvent effects are not the primary criteria that determine the relative population distributions of tautomeric carboxylate (C(-)) and phenoxide (P(-)) ions (m/z 137) generated by electrospray ionization of p-hydroxybenzoic acid. In addition, we propose that the observed ratio of the P(-) and C(-) forms indirectly reflects the relative contribution of the charge-residue or ion-evaporation process that occurs during the electrospray ion generation process. PMID:27164186