Science.gov

Sample records for acid gas control

  1. 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.

  2. 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...

  3. 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,…

  4. 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.

  5. Optimize acid gas removal

    SciTech Connect

    Nicholas, D.M.; Wilkins, J.T.

    1983-09-01

    Innovative design of physical solvent plants for acid gas removal can materially reduce both installation and operating costs. A review of the design considerations for one physical solvent process (Selexol) points to numerous arrangements for potential improvement. These are evaluated for a specific case in four combinations that identify an optimum for the case in question but, more importantly, illustrate the mechanism for use for such optimization elsewhere.

  6. Acidic gas capture by diamines

    DOEpatents

    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.

  7. Optimal control system design of an acid gas removal unit for an IGCC power plants with CO2 capture

    SciTech Connect

    Jones, D.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future IGCC plants with CO{sub 2} capture should be operated optimally in the face of disturbances without violating operational and environmental constraints. To achieve this goal, a systematic approach is taken in this work to design the control system of a selective, dual-stage Selexol-based acid gas removal (AGR) unit for a commercial-scale integrated gasification combined cycle (IGCC) power plant with pre-combustion CO{sub 2} capture. The control system design is performed in two stages with the objective of minimizing the auxiliary power while satisfying operational and environmental constraints in the presence of measured and unmeasured disturbances. In the first stage of the control system design, a top-down analysis is used to analyze degrees of freedom, define an operational objective, identify important disturbances and operational/environmental constraints, and select the control variables. With the degrees of freedom, the process is optimized with relation to the operational objective at nominal operation as well as under the disturbances identified. Operational and environmental constraints active at all operations are chosen as control variables. From the results of the optimization studies, self-optimizing control variables are identified for further examination. Several methods are explored in this work for the selection of these self-optimizing control variables. Modifications made to the existing methods will be discussed in this presentation. Due to the very large number of candidate sets available for control variables and due to the complexity of the underlying optimization problem, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel Computing® toolbox from Mathworks®. The second stage is a bottom-up design of the control layers used for the operation of the process. First, the regulatory control layer is

  8. Acid gas burner

    SciTech Connect

    Polak, B.

    1991-04-23

    This patent describes a burner for combusting a waste gas. It comprises a throat section; a fire tube downstream from the throat section in communication therewith; an air duct section upstream from the throat section in communication therewith; a centrally located nozzle means for introduction of a fuel in the throat section in a downstream direction toward the fire tube; means upstream from the throat section for forming a downstream directed swirling combustion air stream substantially in an annular ring along the sidewalls of the throat section; and means for introducing a waste gas stream into the throat section downstream of the nozzle means in a forwardly biased but swirling direction opposite to that of the swirling combustion air stream.

  9. More on Effects Controlling Carboxylic Acidity.

    ERIC Educational Resources Information Center

    Schwartz, Lowell M.

    1981-01-01

    Gas phase acidity data shown are offered to writers of elementary organic chemistry texts for replacement of the aqueous phase data that are universally used. Relative acidities in the gas phase are controlled virtually exclusively by enthalpic factors. Structural-energetic explanations of acidic trends can therefore be used. (SK)

  10. Mechanisms controlling the leaching kinetics of fixated flue gas desulfurization (FGD) material under neutral and acidic conditions.

    PubMed

    Cheng, Chin-Min; Walker, Harold W; Bigham, Jerry M

    2007-01-01

    A number of agricultural and engineering uses for fixated flue gas desulfurization (FGD) material exist; however, the potential for leaching of hazardous elements has limited widespread application and the processes controlling the leaching of this material are poorly understood. In this study, a flow-through rotating-disk system was applied to elucidate the relative importance of bulk diffusion, pore diffusion, and surface chemical reaction in controlling the leaching of fixated FGD material under pH conditions ranging from 2.2 to 6.8. Changing the hydrodynamics in the rotating disk system did not affect the leaching kinetics at both pH 2.2 and 6.8, indicating that bulk diffusion was not the kinetic-limiting step. Application of the shrinking core model (SCM) to the data suggested a surface reaction-controlled mechanism, rather than a pore diffusion mechanism. The leaching of fixated FGD material increased with decreasing pH, suggesting it can be described by a combination of an intrinsic hydration reaction and a proton-promoted dissolution reaction. X-ray diffraction (XRD) and elemental composition analyses before and after leaching suggests that for most elements a number of solid phases controlled the leaching process.

  11. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    EPA Science Inventory

    Discussed are acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE), both developed ...

  12. Surfactant control of gas uptake: effect of butanol films on HCl and HBr entry into supercooled sulfuric acid.

    PubMed

    Lawrence, Jennifer R; Glass, Samuel V; Park, Seong-Chan; Nathanson, Gilbert M

    2005-08-25

    The entry of HCl into 60-68 wt % D(2)SO(4) and HBr into 68 wt % acid containing 0-0.18 M 1-butanol was monitored by measuring the fractions of impinging HCl and HBr molecules that desorb as DCl and DBr after undergoing H --> D exchange within the deuterated acid. The addition of 0.18 M butanol to the acid creates butyl films that reach approximately 80% surface coverage at 213 K. Surprisingly, this butyl film does not impede exchange but instead enhances it: the HCl --> DCl exchange fractions increase from 0.52 to 0.74 for 60 wt % D(2)SO(4) and from 0.14 to 0.27 for 68 wt % D(2)SO(4). HBr --> DBr exchange increases even more sharply, rising from 0.22 to 0.65 for 68 wt % D(2)SO(4). We demonstrate that this enhanced exchange corresponds to enhanced uptake into the butyl-coated acid for HBr and infer this equivalence for HCl. In contrast, the entry probability of the basic molecule CF(3)CH(2)OH exceeds 0.85 at all acid concentrations and is only slightly diminished by the butyl film. The OD groups of surface butanol molecules may assist entry by providing extra interfacial protonation sites for HCl and HBr dissociation. The experiments suggest that short-chain surfactants in sulfuric acid aerosols do not hinder heterogeneous reactions of HCl or HBr with other solute species.

  13. 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.

  14. Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides

    NASA Astrophysics Data System (ADS)

    Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

    2007-09-01

    Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  15. Gas turbine engine fuel control

    NASA Technical Reports Server (NTRS)

    Gold, H. S. (Inventor)

    1973-01-01

    A variable orifice system is described that is responsive to compressor inlet pressure and temperature, compressor discharge pressure and rotational speed of a gas-turbine engine. It is incorporated into a hydraulic circuit that includes a zero gradient pump driven at a speed proportional to the speed of the engine. The resulting system provides control of fuel rate for starting, steady running, acceleration and deceleration under varying altitudes and flight speeds.

  16. Gas-controlled dynamic vacuum insulation with gas gate

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1994-06-07

    Disclosed is a dynamic vacuum insulation comprising sidewalls enclosing an evacuated chamber and gas control means for releasing hydrogen gas into a chamber to increase gas molecule conduction of heat across the chamber and retrieving hydrogen gas from the chamber. The gas control means includes a metal hydride that absorbs and retains hydrogen gas at cooler temperatures and releases hydrogen gas at hotter temperatures; a hydride heating means for selectively heating the metal hydride to temperatures high enough to release hydrogen gas from the metal hydride; and gate means positioned between the metal hydride and the chamber for selectively allowing hydrogen to flow or not to flow between said metal hydride and said chamber.

  17. Gas-controlled dynamic vacuum insulation with gas gate

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1994-06-07

    Disclosed is a dynamic vacuum insulation comprising sidewalls enclosing an evacuated chamber and gas control means for releasing hydrogen gas into a chamber to increase gas molecule conduction of heat across the chamber and retrieving hydrogen gas from the chamber. The gas control means includes a metal hydride that absorbs and retains hydrogen gas at cooler temperatures and releases hydrogen gas at hotter temperatures; a hydride heating means for selectively heating the metal hydride to temperatures high enough to release hydrogen gas from the metal hydride; and gate means positioned between the metal hydride and the chamber for selectively allowing hydrogen to flow or not to flow between said metal hydride and said chamber. 25 figs.

  18. Fine temporal control of the medium gas content and acidity and on-chip generation of series of oxygen concentrations for cell cultures.

    PubMed

    Polinkovsky, Mark; Gutierrez, Edgar; Levchenko, Andre; Groisman, Alex

    2009-04-21

    We describe the design, operation, and applications of two microfluidic devices that generate series of concentrations of oxygen, [O(2)], by on-chip gas mixing. Both devices are made of polydimethylsiloxane (PDMS) and have two layers of channels, the flow layer and the gas layer. By using in-situ measurements of [O(2)] with an oxygen-sensitive fluorescent dye, we show that gas diffusion through PDMS leads to equilibration of [O(2)] in an aqueous solution in the flow layer with [O(2)] in a gas injected into the gas layer on a time scale of approximately 1 sec. Injection of carbon dioxide into the gas layer causes the pH in the flow layer to drop within approximately 0.5 sec. Gas-mixing channel networks of both devices generate series of 9 gas mixtures with different [O(2)] from two gases fed to the inlets, thus creating regions with 9 different [O(2)] in the flow layer. The first device generates nitrogen-oxygen mixtures with [O(2)] varying linearly between 0 and 100%. The second device generates nitrogen-air mixtures with [O(2)] varying exponentially between 0 and 20.9%. The flow layers of the devices are designed for culturing bacteria in semi-permeable microchambers, and the second device is used to measure growth curves of E. coli colonies at 9 different [O(2)] in a single experiment. The cell division rates at [O(2)] of 0, 0.2, and 0.5% are found to be significantly different, further validating the capacity of the device to set [O(2)] in the flow layer with high precision and resolution. The degree of control of [O(2)] achieved in the devices and the robustness with respect to oxygen consumption due to respiration would be difficult to match in a traditional large-scale culture. The proposed devices and technology can be used in research on bacteria and yeast under microaerobic conditions and on mammalian cells under hypoxia.

  19. 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.

  20. Control of the Position of Oxygen Delivery in Soybean Lipoxygenase-1 by Amino Acid Side Chains within a Gas Migration Channel.

    PubMed

    Collazo, Lara; Klinman, Judith P

    2016-04-22

    Understanding gas migration pathways is critical to unraveling structure-function relationships in enzymes that process gaseous substrates such as O2, H2, and N2 This work investigates the role of a defined pathway for O2 in regulating the peroxidation of linoleic acid by soybean lipoxygenase 1. Computational and mutagenesis studies provide strong support for a dominant delivery channel that shuttles molecular oxygen to a specific region of the active site, thereby ensuring the regio- and stereospecificity of product. Analysis of reaction kinetics and product distribution in channel mutants also reveals a plasticity to the gas migration pathway. The findings show that a single site mutation (I553W) limits oxygen accessibility to the active site, greatly increasing the fraction of substrate that reacts with oxygen free in solution. They also show how a neighboring site mutation (L496W) can result in a redirection of oxygen toward an alternate position of the substrate, changing the regio- and stereospecificity of peroxidation. The present data indicate that modest changes in a protein scaffold may modulate the access of small gaseous molecules to enzyme-bound substrates.

  1. 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…

  2. 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.

  3. Adaptive control system for gas producing wells

    SciTech Connect

    Fedor, Pashchenko; Sergey, Gulyaev; Alexander, Pashchenko

    2015-03-10

    Optimal adaptive automatic control system for gas producing wells cluster is proposed intended for solving the problem of stabilization of the output gas pressure in the cluster at conditions of changing gas flow rate and changing parameters of the wells themselves, providing the maximum high resource of hardware elements of automation.

  4. Density, phase behavior keys to acid gas injection

    SciTech Connect

    Carroll, J.J.; Lui, D.W.

    1997-06-23

    Acid gas injection requires an understanding of the complexities of gas phase behavior and physical properties. Injected acid gas streams typically come from the top of the regenerator reflux accumulator of an amine unit. Thus, they are composed mainly of hydrogen sulfide (H{sub 2}S) and carbon dioxide (CO{sub 2}) with significant amounts of methane and lesser amounts of other hydrocarbons. The stream is also saturated with water. The stream from the amine plant has a low pressure and must be compressed to a higher pressure for injection into a disposal well. This article summarizes the available research on acid gas phase behavior and density calculations.

  5. PID control of gas pipelines

    SciTech Connect

    Coltharp, B.; Bergmann, J.

    1996-09-01

    The use of low cost digital controllers for pipeline control is increasing as the reliability and cost improves. In pipeline applications, the proportional, integral, and derivative (PID) controller algorithm is often used. However, the unique problems associated with pipeline operation have caused manufacturers to modify the basic control algorithms. Features such as set point ramping, built in pressure control, freeze on input error, and high and low output limits help assure safe and predictable pipeline operation.

  6. Controlling Gas-Flow Mass Ratios

    NASA Technical Reports Server (NTRS)

    Morris, Brian G.

    1990-01-01

    Proposed system automatically controls proportions of gases flowing in supply lines. Conceived for control of oxidizer-to-fuel ratio in new gaseous-propellant rocket engines. Gas-flow control system measures temperatures and pressures at various points. From data, calculates control voltages for electronic pressure regulators for oxygen and hydrogen. System includes commercially available components. Applicable to control of mass ratios in such gaseous industrial processes as chemical-vapor depostion of semiconductor materials and in automotive engines operating on compressed natural gas.

  7. Looking Northwest at Furnace Control Panels and Gas Control Furnace ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Northwest at Furnace Control Panels and Gas Control Furnace in Red Room Within Recycle Recovery Building - Hematite Fuel Fabrication Facility, Recycle Recovery Building, 3300 State Road P, Festus, Jefferson County, MO

  8. Microbially induced organic acid underdeposit attack in a gas pipeline

    SciTech Connect

    Dias, O.C.; Bromel, M.C. )

    1990-04-01

    A leaking undersea carbon-steel gas pipeline was investigated, and attack was confined to low areas where water had accumulated.Analyses showed that pitting, which occurred under deposits, was caused by organic acids generated by bacteria. The metabolic activities of anaerobic sporeformers produce these acids. Alkyl amine carboxylic acid and metronidizole were effective deterrents at low concentrations.

  9. Control apparatus for hot gas engine

    SciTech Connect

    Stotts, Robert E.

    1986-01-01

    A mean pressure power control system for a hot gas (Stirling) engine utilizing a plurality of supply tanks for storing a working gas at different pressures. During pump down operations gas is bled from the engine by a compressor having a plurality of independent pumping volumes. In one embodiment of the invention, a bypass control valve system allows one or more of the compressor volumes to be connected to the storage tanks. By selectively sequencing the bypass valves, a capacity range can be developed over the compressor that allows for lower engine idle pressures and more rapid pump down rates.

  10. Gas Control System for HEAO-B

    NASA Technical Reports Server (NTRS)

    Taylor, B.; Brissette, R.; Humphrey, A.; Morris, J.; Luger, J.; Swift, W.

    1978-01-01

    The HEAO-B Gas Control System consists of a high pressure gas storage supply together with distribution and regulation assemblies and their associated electronics for management of gas required for HEAO-B X-ray counter experiments. The Gas Control System replenishes a gas mixture (82 percent argon, 12.3 percent carbon dioxide, 5.7 percent xenon) in the counter volumes which is lost by: diffusion through controlled leakage plugs, diffusion through counter windows, and consumption resulting from periodic purges. The gas density in each counter volume is maintained constant to within 0.25 percent by comparison with a sealed reference volume. The system is fully redundant, capable of operating at atmospheric pressure as well as in a vacuum, contains interlocks which shut down gas flow in the event of either leakage or excessive pressure, and is able to shut down counter high voltage if counter pressure is abnormally low. The system is electronically controlled by ground command and self-sustaining in orbit for a period of at least one year.

  11. Gas Analysis and Control Methods for Thermal Batteries

    DTIC Science & Technology

    2013-09-01

    September 2013 Gas Analysis and Control Methods for Thermal Batteries Frank C. Krieger and Michael S. Ding Sensors and Electron Devices...certified gas cylinder calibration tests. These measured gas pressures all include the 0.5813 total volume fraction of argon gas in the certified gas...volume fraction of argon gas in the certified gas cylinder. .....................................................................8 Table 4. Moles of

  12. Gas-phase acidities of binary hydrides.

    NASA Technical Reports Server (NTRS)

    Brauman, J. I.; Eyler, J. R.; Blair, L. K.; White, M. J.; Comisarow, M. B.; Smyth, K. C.

    1971-01-01

    The preferred direction of proton transfer in a reaction between a hydride molecule and a hydride ion was studied in order to determine the relative acidities of some binary hydrides. Sufficient data are presented to make clear the periodic trends in acidities and the underlying trends in other fundamental thermochemical quantities which influence acidity. The bond dissociation energies and electron affinities of the hydrides considered are listed in a table.

  13. Hydrate Control for Gas Storage Operations

    SciTech Connect

    Jeffrey Savidge

    2008-10-31

    The overall objective of this project was to identify low cost hydrate control options to help mitigate and solve hydrate problems that occur in moderate and high pressure natural gas storage field operations. The study includes data on a number of flow configurations, fluids and control options that are common in natural gas storage field flow lines. The final phase of this work brings together data and experience from the hydrate flow test facility and multiple field and operator sources. It includes a compilation of basic information on operating conditions as well as candidate field separation options. Lastly the work is integrated with the work with the initial work to provide a comprehensive view of gas storage field hydrate control for field operations and storage field personnel.

  14. Application of microturbines to control emissions from associated gas

    DOEpatents

    Schmidt, Darren D.

    2013-04-16

    A system for controlling the emission of associated gas produced from a reservoir. In an embodiment, the system comprises a gas compressor including a gas inlet in fluid communication with an associated gas source and a gas outlet. The gas compressor adjusts the pressure of the associated gas to produce a pressure-regulated associated gas. In addition, the system comprises a gas cleaner including a gas inlet in fluid communication with the outlet of the gas compressor, a fuel gas outlet, and a waste product outlet. The gas cleaner separates at least a portion of the sulfur and the water from the associated gas to produce a fuel gas. Further, the system comprises a gas turbine including a fuel gas inlet in fluid communication with the fuel gas outlet of the gas cleaner and an air inlet. Still further, the system comprises a choke in fluid communication with the air inlet.

  15. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas system... the cargo area meeting paragraph (a) of this section; (c) Automatic and manual inert gas...

  16. Gas chromatographic determination of oxalic acid in foods.

    PubMed

    Ohkawa, H

    1985-01-01

    A new quantitative gas chromatographic (GC) method has been developed for the determination of oxalic acid in foods. Solid sample is extracted with water (soluble oxalic acid) or 2N hydrochloric acid (total oxalic acid) at room temperature. An aliquot of sample extract is evaporated to dryness, and the oxalic acid in the residue is methylated with 7% hydrochloric acid-methanol. The reaction mixture is extracted with chloroform, and dimethyl oxalate is quantitated by GC. Recovery of oxalic acid added to liquid samples averaged 100.6%; recoveries from extracts of solid samples were 96.2-99.5 and 97.2-100.1% for water and hydrochloric acid extractions, respectively. Results are shown for determination of oxalic acid in spinach and beverages. The technique is simple, rapid, and accurate, and small samples may be used. The limit of determination is 20 micrograms.

  17. Ancillary effects of selected acid deposition control policies

    SciTech Connect

    Moe, R.J.; Lyke, A.J.; Nesse, R.J.

    1986-08-01

    NAPAP is examining a number of potential ways to reduce the precursors (sulfur dioxide and nitrogen oxides) to acid deposition. However, the policies to reduce acid deposition will have other physical, biological and economic effects unrelated to acid deposition. For example, control policies that reduce sulfur dioxide emissions may also increase visibility. The effects of an acid deposition policy that are unrelated to acid deposition are referred to as ''ancillary'' effects. This reserch identifies and characterizes the principle physical and economic ancillary effects associated with acid deposition control and mitigation policies. In this study the ancillary benefits associated with four specific acid deposition policy options were investigated. The four policy options investigated are: (1) flue gas desulfurization, (2) coal blending or switching, (3) reductions in automobile emissions of NO/sub x/, and (4) lake liming. Potential ancillary benefits of each option were identified and characterized. Particular attention was paid to the literature on economic valuation of potential ancillary effects.

  18. Turbine gas temperature measurement and control system

    NASA Technical Reports Server (NTRS)

    Webb, W. L.

    1973-01-01

    A fluidic Turbine Inlet Gas Temperature (TIGIT) Measurement and Control System was developed for use on a Pratt and Whitney Aircraft J58 engine. Based on engine operating requirements, criteria for high temperature materials selection, system design, and system performance were established. To minimize development and operational risk, the TIGT control system was designed to interface with an existing Exhaust Gas Temperature (EGT) Trim System and thereby modulate steady-state fuel flow to maintain a desired TIGT level. Extensive component and system testing was conducted including heated (2300F) vibration tests for the fluidic sensor and gas sampling probe, temperature and vibration tests on the system electronics, burner rig testing of the TIGT measurement system, and in excess of 100 hours of system testing on a J58 engine. (Modified author abstract)

  19. Gas Chromatographic Analysis of Acidic Indole Auxins in Nicotiana1

    PubMed Central

    Bayer, Margret H.

    1969-01-01

    Acidic indole auxins have been extracted from N. glauca, N. langsdorffii and their 2 tumor-prone 4n- and 2n-hybrids. After purification of the extracts and thin-layer chromatography, acidic indoles were subjected to esterification and gas chromatography. The esters of 4 indole acids were detected and determined: indole-3-acetic acid, indole-3-carboxylic acid, indole-3-propionic acid and indole-3-butyric acid. The indolic nature of fractionated samples was confirmed by spectrophotofluorometry and the physiological significance of the indole esters proven in a biotest. A substantial increase in extractable indole-3-butyric acid in the tumor-prone hybrids suggests an additional pathway of auxin synthesis in these tissues. PMID:5774173

  20. Anchoring the gas-phase acidity scale: From formic acid to methanethiol

    NASA Astrophysics Data System (ADS)

    Eyet, Nicole; Villano, Stephanie M.; Bierbaum, Veronica M.

    2009-06-01

    We have measured the gas-phase acidities of nine compounds: formic acid, acetic acid, 1,3-propanedithiol, 2-methyl-2-propanethiol, 3-methyl-1-butanethiol, 2-propanethiol, 1-propanethiol, ethanethiol, and methanethiol, with acidities ranging from 338.6 to 351.1 kcal mol-1 using proton transfer kinetics and the resulting equilibrium constants. These acids were anchored to the well-known acidity of hydrogen sulfide; the measured acidities are in good agreement with previous experimental values, but error bars are significantly reduced. The gas-phase acidity of 3-methyl-1-butanethiol was determined to be 347.1 (5) kcal mol-1; there were no previous measurements of this value. Entropies of deprotonation were calculated and enthalpies of deprotonation were determined.

  1. Seasonal Patterns of Acid Metabolism and Gas Exchange in Opuntia basilaris1

    PubMed Central

    Szarek, Stan R.; Ting, Irwin P.

    1974-01-01

    Acid metabolism and gas exchange studies were conducted in situ on the cactus Opuntia basilaris Engelm. and Bigel. A pattern of significant seasonal variation was evident. The pattern was controlled by rainfall, which significantly influenced plant water potentials, total gas transfer resistances, and nocturnal organic acid synthesis. In winter and early spring, when plant water stress was mild, stomatal and mesophyll resistances remained low, permitting enhanced nocturnal assimilation of 14CO2. The day/night accumulation of acidity was large during these seasons. In summer and fall, plant water stress was moderate, although soil water stress was severe. The nocturnal assimilation of 14CO2 was very low during these seasons, even in stems with open stomata, indicating large mesophyll resistances restricting exogenous gas incorporation. The day/night accumulation of acidity was reduced, and a low level of acid metabolism persisted throughout this period. The rapid response to a midsummer rainfall emphasizes the importance of plant water potential as a parameter controlling over-all metabolic activity. The seasonal variations of acid metabolism and gas exchange significantly influenced the efficiency of water use and carbon dioxide assimilation. Periods of maximal efficiency followed rainfall throughout the course of the year. PMID:16658842

  2. Power control for hot gas engines

    NASA Technical Reports Server (NTRS)

    Macglashan, W. F. (Inventor)

    1980-01-01

    A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two level gears to provide a phase angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

  3. Seven Conformers of Pipecolic Acid Identified in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Cabezas, Carlos; Simao, Alcides; Alonso, José L.

    2016-06-01

    The multiconformational landscape of the non-proteinogenic cyclic amino acid pipecolic acid has been explored in the gas phase. Solid pipecolic acid (m.p. 280°C) was vaporized by laser ablation (LA) and expanded in a supersonic jet where the rotational spectra of seven conformers were obtained by broadband microwave spectroscopy (CP-FTMW). All conformers were conclusively identified by comparison of the experimental spectroscopic constants with those predicted theoretically. The relative stability of the conformers rests on a delicate balance of the different intramolecular hydrogen bonds established between the carboxylic and the amino groups.

  4. 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.

  5. 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.

  6. 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.

  7. Substituent effects on the gas-phase acidity of silane

    SciTech Connect

    Gordon, M.S.; Volk, D.E. ); Gano, D.R. )

    1989-12-20

    In a previous paper, the gas-phase acidities of XH{sub n} compounds (X = C, N, O, F, Si, P, S, Cl) were predicted with ab initio wave functions. At the MP4{sup 2} level of theory with extended basis sets acidities for these species were determined to be within 2 kcal/mol of experimental value. In the present work, with 6-31G(d) geometries and full MP4/MC-311++G{sup 6}(3df,2pd) energies, the effects of CH{sub 3}, NH{sub 2}, OH, F, SiH{sub 3}, PH{sub 2}, SH, and Cl on the gas-phase acidity of silane are examined. Only a few related calculations have been carried out. All calculations were performed with Gaussian86, and all structures were verified as minima by diagonalizing the analytically determined hessians. Only the valence electrons were correlated in the perturbation theory calculations.

  8. Power control system for a hot gas engine

    DOEpatents

    Berntell, John O.

    1986-01-01

    A power control system for a hot gas engine of the type in which the power output is controlled by varying the mean pressure of the working gas charge in the engine has according to the present invention been provided with two working gas reservoirs at substantially different pressure levels. At working gas pressures below the lower of said levels the high pressure gas reservoir is cut out from the control system, and at higher pressures the low pressure gas reservoir is cut out from the system, thereby enabling a single one-stage compressor to handle gas within a wide pressure range at a low compression ratio.

  9. Preventing and controlling accidental gas releases

    NASA Astrophysics Data System (ADS)

    Moskowitz, P. D.; Fthenakis, V. M.; Kalb, P. D.

    1988-07-01

    Toxic, flammable, and explosive gases may be used in photovoltaic cell research laboratories and in commercial manufacturing facilities. Accidental release of these materials can present hazards to life and property. Accidents can arise from a variety of mechanical and human related failures. These can occur from the time materials are received at the loading dock of the facility to the time treated gases are discharged to the atmosphere through a stack. Each type of initiating event may require a different control approach. These may range from the training and certification of plant workers charged with the handling of gas cylinder hookups to installation of emergency pollution control systems. Since engineering options for controlling released materials are limited, emphasis should be placed on administrative and engineering approaches for preventing such accidents. These are likely to be the most effective approaches for protecting life and property.

  10. STOVL hot gas ingestion control technology

    SciTech Connect

    Amuedo, K.C.; Williams, B.R.; Flood, J.D. ); Johns, A.L. )

    1991-01-01

    This paper reports on a comprehensive wind tunnel test program conducted to evaluate control of Hot Gas Ingestion (HGI) on a 9.2 percent scale model of the McDonnell Aircraft Company model 279-3C advanced Short Takeoff and Vertical Landing (STOVL) configuration. The test was conducted in the NASA-Lewis Research Center 9 ft by 15 ft Low Speed Wind Tunnel during the summer of 1987. Initial tests defined baseline HGI levels as determined by engine face temperature rise and temperature distortion. Subsequent testing was conducted to evaluate HGI control parametrically using Lift Improvement Devices (LIDs), forward nozzle splay angle, a combination of LIDs and forward nozzle splay angle, and main inlet blocking. The results from this test program demonstrate that HGI can be effectively controlled and that HGI is not a barrier to STOVL aircraft development.

  11. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  12. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  13. EXPERIMENTAL DESIGN OF A FLUID-CONTROLLED HOT GAS VALVE

    DTIC Science & Technology

    Effort is described toward development of a hot gas jet reaction valve utilizing boundary layer techniques to control a high pressure, high...temperature gas stream. The result has been the successful design of a hot gas valve in a reaction control system utilizing fluid-controlled bi-stable

  14. 46 CFR 154.904 - Inert gas system: Controls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inert gas system: Controls. 154.904 Section 154.904... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Atmospheric Control in Cargo Containment Systems § 154.904 Inert gas system: Controls. The inert gas...

  15. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2000-12-01

    A test program is being sponsored by the US Department of Energy (DOE), EPRI, FirstEnergy, and TVA to investigate furnace injection of alkaline sorbents as a means of reducing sulfuric acid concentrations in the flue gas from coal-fired boilers. This test program is being conducted at the FirstEnergy Bruce Mansfield Plant (BMP), although later testing will be conducted at a TVA plant. A sorbent injection test was conducted the week of April 18, 2000. The test was the first of several short-term (one- to two-week duration) tests to investigate the effectiveness of various alkaline sorbents for sulfuric acid control and the effects of these sorbents on boiler equipment performance. This first short-term test investigated the effect of injecting dry dolomite powder (CaCO{sub 3} {center_dot} MgCO{sub 3}), a mineral similar to limestone, into the furnace of Unit 2. During the test program, various analytical techniques were used to assess the effects of sorbent injection. These primarily included sampling with the controlled condensation system (CCS) for determining flue gas SO{sub 3} content and an acid dew-point (ADP) meter for determining the sulfuric acid dew point (and, indirectly, the concentration of sulfuric acid) of the flue gas. EPA Reference Method 26a was used for determining hydrochloric acid (HCl) and hydrofluoric acid (HF), as well and chlorine (Cl{sub 2}) and fluorine (F{sub 2}) concentrations in the flue gas. Fly ash resistivity was measured using a Southern Research Institute (SRI) point-to-plane resistivity probe, and unburned carbon in fly ash was determined by loss on ignition (LOI). Coal samples were also collected and analyzed for a variety of parameters. Finally, visual observations were made of boiler furnace and convective pass surfaces prior to and during sorbent injection.

  16. Method for controlling gas metal arc welding

    DOEpatents

    Smartt, Herschel B.; Einerson, Carolyn J.; Watkins, Arthur D.

    1989-01-01

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections.

  17. Method for controlling gas metal arc welding

    DOEpatents

    Smartt, H.B.; Einerson, C.J.; Watkins, A.D.

    1987-08-10

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections. 3 figs., 1 tab.

  18. 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

  19. The intrinsic (gas-phase) acidities of bridgehead alcohols

    NASA Astrophysics Data System (ADS)

    Herrero, Rebeca; Dávalos, Juan Z.; Abboud, José-Luis M.; Alkorta, I.; Koppel, I.; Koppel, I. A.; Sonoda, T.; Mishima, M.

    2007-11-01

    The gas-phase acidities of 1-adamantanol and perfluoro1-adamantanol were determined by means of Fourier transform ion cyclotron resonance spectrometry (FT-ICR). The acidity of perfluoro1-adamantanol seems to be the highest ever reported for an alcohol. A computational study of these species and their anions at both the MP2/6-311 + G(d,p) and B3LYP/6-311 + G(d,p) levels was performed. Also studied were the tertiary alcohols (including their perfluorinated forms) derived from norbornane, bicyclo[2.2E2]octane and cubane. It was found that: (i) the intrinsic acidity of non-fluorinated bridgehead alcohols increases with the strain of the hydrocarbon framework and, (ii) perfluorination of these compounds strongly increases their acidity and, likely, significantly modifies their internal strain.

  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.

  1. Sensors control gas metal arc welding

    SciTech Connect

    Siewert, T.A.; Madigan, R.B.; Quinn, T.P.

    1997-04-01

    The response time of a trained welder from the time a weld problem is identified to the time action is taken is about one second--especially after a long, uneventful period of welding. This is acceptable for manual welding because it is close to the time it takes for the weld pool to solidify. If human response time were any slower, manual welding would not be possible. However, human response time is too slow to respond to some weld events, such as melting of the contact tube in gas metal arc welding (GMAW), and only automated intelligent control systems can react fast enough to correct or avoid these problems. Control systems incorporate welding knowledge that enables intelligent decisions to be made about weld quality and, ultimately, to keep welding parameters in the range where only high-quality welds are produced. This article discusses the correlation of electrical signals with contact-tube wear, changes in shielding gas, changes in arc length, and other weld process data.

  2. 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.

  3. Determination of bile acids by hollow fibre liquid-phase microextraction coupled with gas chromatography.

    PubMed

    Ghaffarzadegan, T; Nyman, M; Jönsson, J Å; Sandahl, M

    2014-01-01

    A method based on hollow-fibre liquid phase microextraction combined with gas chromatography was developed for determination of specific bile acids in caecal materials of rats. Nine unconjugated bile acids, including the primary bile acids (cholic acid, chenodeoxycholic acid and α-muricholic acid) and the secondary bile acids (lithocholic acid, deoxycholic acid, ursodeoxycholic acid, hyodeoxycholic acid, β-muricholic acid and ω-muricholic acid) were quantified. Extraction conditions were evaluated, including: sample pH, type of organic solvent and amount of caecal material to be extracted. To compensate for sample matrix effects during extraction the method of standard addition was applied. The satisfactory linearity (r(2)>0.9840), high recovery (84.2-108.7%) and good intra-assay (6.3-10.6%) and inter-assay (6.9-11.1%) precision illustrated the good performance of the present method. The method is rapid, simple and capable of detecting and determining bile acids with limit of detection (LOD) ranged from 0.002 to 0.067μg/mL and limits of quantification (LOQ) varied from 0.006 to 0.224μg/mL. The results indicated that the concentration of some secondary bile acids, which usually are associated with health problems, were lower in rats fed with fermentable dietary fibre compared with a fibre free control diet, while the concentration of primary bile acids, usually connected with positive health effects, were higher in rats fed with diets containing dietary fibre. Of the dietary fibres, guar gum and to some extent the mixture of pectin+guar gum had the most positive effects. Thus, it was concluded that the composition of bile acids can be affected by the type of diet.

  4. Adipic gets the acid test as flue gas scrubber additive

    SciTech Connect

    Miller, I.R.

    1980-02-11

    The first full-scale demonstration of adipic acid for such use, to be conducted early in the summer of 1980 in a 200 MW power plant burning high-sulfur coal, is designed to clarify the costs and show how to reduce losses of adipic acid via degradation. Adipic acid improves SO/sub 2/ removal by acting as a buffer to limit the pH drop normally occurring at the gas-liquid interface so that the higher SO/sub 2/ concentration in the surface film improves liquid-phase mass transfer; it also promotes higher limestone utilization. Prepared by the Tennessee Valley Authority, a preliminary economic analysis for a 500 MW plant burning 4% sulfur coal indicates that the addition of 1500 ppM of adipic acid (limestone at $7/ton and the acid at $840/ton) would raise SO/sub 2/ removal from 90 to 95%, reduce the total capital investment from $41.5 to $39.5 million, and have a first year revenue requirement of $19.9 million vs. $20.9 million without the acid. The large-scale trial will also help clarify concern over unpleasant odors that have been reported at test sites of the limestone/adipic system; valeric acid has been identified as the cause.

  5. Power control for hot gas engines

    SciTech Connect

    Frosch, R.A.; Macglashan, W.F.

    1980-10-21

    A hot gas engine is described in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential-type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two bevel gears to provide a phase-angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

  6. 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

  7. Amino Acid Auxotrophy as Immunological Control Nodes

    PubMed Central

    Murray, Peter J.

    2016-01-01

    Summary Cells of the immune system are auxotrophs for most amino acids, including non-essential ones. Arginine and tryptophan are used within the regulatory immune networks to control proliferation and function through pathways that deplete the amino acid, or create regulatory molecules such as nitric oxide or kynurenines. Strategies to harness amino acid auxotrophy to block cancerous lymphocyte growth have been attempted for decades, with limited success. How immune cells integrate information about external essential amino acids supplies and transfer signals to growth and activation pathways remains unclear, but has potential for pathway discovery. Emerging insights may lead to strategies to both degrade amino acids and to block the immunoregulatory pathways controlled by amino acids. PMID:26784254

  8. Pressure-Sensitive System for Gas-Temperature Control

    NASA Technical Reports Server (NTRS)

    Cesaro, Richard S; Matz, Norman

    1948-01-01

    A thermodynamic relation is derived and simplified for use as a temperature-limiting control equation involving measurement of gas temperature before combustion and gas pressures before and after combustion. For critical flow in the turbine nozzles of gas-turbine engines, the control equation is further simplified to require only measurements upstream of the burner. Hypothetical control systems are discussed to illustrate application of the control equations.

  9. Software to Control and Monitor Gas Streams

    NASA Technical Reports Server (NTRS)

    Arkin, C.; Curley, Charles; Gore, Eric; Floyd, David; Lucas, Damion

    2012-01-01

    This software package interfaces with various gas stream devices such as pressure transducers, flow meters, flow controllers, valves, and analyzers such as a mass spectrometer. The software provides excellent user interfacing with various windows that provide time-domain graphs, valve state buttons, priority- colored messages, and warning icons. The user can configure the software to save as much or as little data as needed to a comma-delimited file. The software also includes an intuitive scripting language for automated processing. The configuration allows for the assignment of measured values or calibration so that raw signals can be viewed as usable pressures, flows, or concentrations in real time. The software is based on those used in two safety systems for shuttle processing and one volcanic gas analysis system. Mass analyzers typically have very unique applications and vary from job to job. As such, software available on the market is usually inadequate or targeted on a specific application (such as EPA methods). The goal was to develop powerful software that could be used with prototype systems. The key problem was to generalize the software to be easily and quickly reconfigurable. At Kennedy Space Center (KSC), the prior art consists of two primary methods. The first method was to utilize Lab- VIEW and a commercial data acquisition system. This method required rewriting code for each different application and only provided raw data. To obtain data in engineering units, manual calculations were required. The second method was to utilize one of the embedded computer systems developed for another system. This second method had the benefit of providing data in engineering units, but was limited in the number of control parameters.

  10. Organic acids as indicators of VOC oxidation: Measurements of formic acid and other gas-phase acids during SOAS

    NASA Astrophysics Data System (ADS)

    Farmer, D.; Brophy, P.; Murschell, T.

    2013-12-01

    Oxidation of volatile organic compounds (VOCs) in the atmosphere affects not only the oxidative capacity of the atmosphere, but also the formation of secondary organic aerosol. Organic acids are produced during VOC oxidation, although additional sources include biomass burning and primary emissions. While some organic acids are semi-volatile and dominantly present in the aerosol phase, formic acid and other small organic acids are dominantly present in the gas phase. The concentrations of these gas-phase organic acids can provide insight into oxidation chemistry. Here, we present measurements made during the Southern Oxidant and Aerosol Study (SOAS) in Centerville, Alabama during the summer of 2013 by a high resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) operated in a novel switching reagent ion mode to measure gas phase organic acids with both acetate (CH3COO-) and iodide (I-) reagent ions. Formic acid was quantified using for both ionization schemes using multiple calibration techniques. In this study, we will focus on the impact of anthropogenic pollutants, including nitrogen and sulfur oxides, on oxidation chemistry, and discuss the potential use of organic acids as tracers for atmospheric oxidation chemistry.

  11. 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.

  12. System for controlling the flow of gas into and out of a gas laser

    DOEpatents

    Alger, Terry; Uhlich, Dennis M.; Benett, William J.; Ault, Earl R.

    1994-01-01

    A modularized system for controlling the gas pressure within a copper vapor or like laser is described herein. This system includes a gas input assembly which serves to direct gas into the laser in a controlled manner in response to the pressure therein for maintaining the laser pressure at a particular value, for example 40 torr. The system also includes a gas output assembly including a vacuum pump and a capillary tube arrangement which operates within both a viscous flow region and a molecular flow region for drawing gas out of the laser in a controlled manner.

  13. Gas-phase acid-base properties of melamine and cyanuric acid.

    PubMed

    Mukherjee, Sumit; Ren, Jianhua

    2010-10-01

    The thermochemical properties of melamine and cyanuric acid were characterized using mass spectrometry measurements along with computational studies. A triple-quadrupole mass spectrometer was employed with the application of the extended Cooks kinetic method. The proton affinity (PA), gas-phase basicity (GB), and protonation entropy (Δ(p)S) of melamine were determined to be 226.2 ± 2.0 kcal/mol, 218.4 ± 2.0 kcal/mol, and 26.2 ± 2.0 cal/mol K, respectively. The deprotonation enthalpy (Δ(acid)H), gas-phase acidity (Δ(acid)G), and deprotonation entropy (Δ(acid)S) of cyanuric acid were determined to be 330.7 ± 2.0 kcal/mol, 322.9 ± 2.0 kcal/mol, and 26.1 ± 2.0 cal/mol K, respectively. The geometries and energetics of melamine, cyanuric acid, and related ionic species were calculated at the B3LYP/6-31+G(d) level of theory. The computationally predicted proton affinity of melamine (225.9 kcal/mol) and gas-phase deprotonation enthalpy of cyanuric acid (328.4 kcal/mol) agree well with the experimental results. Melamine is best represented as the imide-like triazine-triamine form and the triazine nitrogen is more basic than the amino group nitrogen. Cyanuric acid is best represented as the keto-like tautomer and the N-H group is the most probable proton donor.

  14. 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.

  15. Gas-Phase Fragmentation Analysis of Nitro-Fatty Acids

    PubMed Central

    Bonacci, Gustavo; Asciutto, Eliana K.; Woodcock, Steven R.; Salvatore, Sonia R.; Freeman, Bruce A.; Schopfer, Francisco J.

    2012-01-01

    Nitro-fatty acids are electrophilic signaling mediators formed in increased amounts during inflammation by nitric oxide and nitrite-dependent redox reactions. A more rigorous characterization of endogenously-generated species requires additional understanding of their gas-phase induced fragmentation. Thus, collision induced dissociation (CID) of nitroalkane and nitroalkene groups in fatty acids were studied in the negative ion mode to provide mass spectrometric tools for their structural characterization. Fragmentation of nitroalkanes occurred mainly through loss of the NO2− anion or neutral loss of HNO2. The CID of nitroalkenes proceeds via a more complex cyclization, followed by fragmentation to nitrile and aldehyde products. Gas-phase fragmentation of nitroalkene functional groups with additional γ or δ unsaturation occurred through a multiple step cyclization reaction process, leading to 5 and 6 member ring heterocyclic products and carbon chain fragmentation. Cyclization products were not obtained during nitroalkane fragmentation, highlighting the role of double bond π electrons during NO2− rearrangements, stabilization and heterocycle formation. The proposed structures, mechanisms and products of fragmentation are supported by analysis of 13C and 15N labeled parent molecules, 6 different nitroalkene positional isomers, 6 nitroalkane positional isomers, accurate mass determinations at high resolution and quantum mechanics calculations. Multiple key diagnostic ion fragments were obtained through this analysis, allowing for the precise placement of double bonds and sites of fatty acid nitration, thus supporting an ability to predict nitro positions in biological samples. PMID:21953257

  16. Use of adipic acid to enhance flue gas desulfurization

    SciTech Connect

    Ostroff, N.; Laslo, D.

    1984-01-01

    From a chemical point of view, FGD is an acid-base neutralization reaction where the overall rate is balanced by the dissolution of (limestone) alkali, and the absorption of sulfur dioxide. The former occurs at a solid/liquid interface, and the latter occurs at a liquid/gas interface. The rate of each of these processes is determined by local conditions, notably, pH. The introduction of a buffering agent lowers the pH at the solid-liquid interface, thereby increasing the rate of limestone dissolution, and simultaneously, raises the pH at the liquid/gas interface, thereby increasing the rate of absorption. Studies performed during the past several years have established that adipic acid is the best available choice for application because of its unique combination of physical and chemical properties, and its price and availability. This paper discusses the theory of adipic acid enhancement and the mathematics used to describe these phenomena trace its history from the laboratory through full scale trials.

  17. Heat pipe temperature control utilizing a soluble gas absorption reservior

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1976-01-01

    A new gas-controlled heat pipe design is described which uses a liquid matrix reservior, or sponge, to replace the standard gas reservior. Reservior volume may be reduced by a factor of five to ten for certain gas-liquid combinations, while retaining the same level of temperature control. Experiments with ammonia, butane, and carbon dioxide control gases with methanol working fluid are discussed.

  18. Assessment of hot gas contaminant control

    SciTech Connect

    Rutkowski, M.D.; Klett, M.G.; Zaharchuk, R.

    1996-12-31

    The objective of this work is to gather data and information to assist DOE in responding to the NRC recommendation on hot gas cleanup by performing a comprehensive assessment of hot gas cleanup systems for advanced coal-based Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) including the status of development of the components of the hot gas cleanup systems, and the probable cost and performance impacts. The scope and time frame of information gathering is generally responsive to the boundaries set by the National Research council (NRC), but includes a broad range of interests and programs which cover hot gas cleanup through the year 2010. As the status of hot gas cleanup is continually changing, additional current data and information are being obtained for this effort from this 1996 METC Contractors` Review Meeting as well as from the 1996 Pittsburgh Coal Conference, and the University of Karlsruhe Symposium. The technical approach to completing this work consists of: (1) Determination of the status of hot gas cleanup technologies-- particulate collection systems, hot gas desulfurization systems, and trace contaminant removal systems; (2) Determination of hot gas cleanup systems cost and performance sensitivities. Analysis of conceptual IGCC and PFBC plant designs with hot gas cleanup have been performed. The impact of variations in hot gas cleanup technologies on cost and performance was evaluated using parametric analysis of the baseline plant designs and performance sensitivity.

  19. Gas-Jet Meniscus Control in Ribbon Growth

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Vonroos, O.

    1983-01-01

    Gas jet used to control shape of meniscus and thus to regulate ribbon thickness in vertical silicon-ribbon growth. Gas jet also cools ribbon, increasing maximum possible pull speed for silicon, contact angle of 11 degrees plus or minus 1 degree required for constant thickness ribbon growth. Cooling effect of gas jet increases maximum possible pull speed.

  20. Biogenic gas: Controls, habitats, and resource potential

    SciTech Connect

    Rice, D.D. )

    1993-01-01

    As much as 20 percent of the world's natural-gas resource is estimated to have been generated by the decomposition of organic matter by anaerobic microbes at low temperatures. This gas is commonly referred to as biogenic gas. Most biogenic gas was generated early in the burial history of sediments. Some biogenic gas was also generated in relatively recent geologic time and is associated with groundwater flow. The factors that favor significant generation of biogenic gas are anoxic conditions, low sulfate content, low temperature, abundant organic matter, and sufficient pore space for the microbes to thrive. Conditions beneficial for the accumulation of biogenic gas include stratigraphic or early structural traps, adequate seals, low permeability, low pressure, early dissolution of the gas, and formation of gas hydrates. Rapid sediment deposition is critical to both the generation and the accumulation of biogenic gas generated during the early stage. Biogenic gas is distinguished by its molecular and isotopic composition. The hydrocarbon fraction is generally more than 99 percent methane, and the diagnostic isotopic composition of the methane component is as follows: [delta][sup 13]C values are generally lighter than -55 parts per thousand (permil), and [delta]D values are usually in the range of -150 to -250 permil. This isotopic composition indicates that the methane generally resulted from CO[sub 2] reduction. Significant accumulations of ancient biogenic gas have been discovered in Africa, Asia, Europe, North America, and South America. These accumulations occur in Mississippian and younger rocks, at burial depths as much as 4,600 m. They are associated with a variety of rock types (carbonate, clastic, and coal), and occur in a variety of marine and nonmarine depositional settings generally characterized by rapid deposition. 111 refs., 13 figs., 3 tabs.

  1. Gas and liquid phase acidity of natural antioxidants.

    PubMed

    Leopoldini, Monica; Russo, Nino; Toscano, Marirosa

    2006-04-19

    The gas phase and in solution absolute and relative acidities of nine natural systems contained in red and white wines were determined through theoretical B3LYP/6-311++G** calculations. The aim was to correlate these thermodynamic quantities to the ability that some of these compounds show in chelating metals ions to carry out an antioxidant action following a mechanism recently reported in the literature. Results indicated that both absolute and relative values are affected by molecular features such as electronic delocalization and conjugation and intramolecular hydrogen bonds. Polyphenols characterized by the ortho-dihydroxy functionality were found to be good candidates to act as metal cation chelating ligands. Some differences in absolute acidities values were encountered in going from vacuum to water solution.

  2. TECHNOLOGICAL OPTIONS FOR ACID RAIN CONTROL

    EPA Science Inventory

    The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions...

  3. 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.

  4. 75 FR 35796 - Busan 74 (2-hydroxypropyl methanethiosulfonate); Chlorine Gas; and Dichromic Acid, et al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... AGENCY Busan 74 (2-hydroxypropyl methanethiosulfonate); Chlorine Gas; and Dichromic Acid, et al... harris.monisha@epa.gov Dichromic Acid EPA-HQ-OPP-2010-02 Rebecca VonDem- Disodium Salt 43 Hagen Dihydrate... Gas; Dichromic Acid, Disodium Salt, Dihydrate, Meta-Cresol (m-Cresol), and Xylenol. Dated: May...

  5. Sub-atmospheric gas purification for EUVL vacuum environment control

    NASA Astrophysics Data System (ADS)

    Srivastava, Abneesh; Pereira, Stenio; Gaffney, Thomas

    2012-03-01

    High purity gas supply for optics purging and cleaning under vacuum is required to be maintained at the output of the mini-environment gas distribution box in EUV scanners. Typically H2 gas is used for cleaning and purging while N2 gas is used for purging H2 lines post exposure. An investigation of gas purifier performance for moisture removal is made under sub-atmospheric pressure conditions. An evaluation of moisture levels as a function of switching between H2 and N2 gas supply states is also conducted. A superior performance (below instrument LDL) is observed for HX (Entegris, Inc.) gas purifier under various test conditions in the 10-100 kPa pressure range. Our preliminary studies provide a better understanding of gas purifier related moisture outgassing under vacuum and should facilitate better control and standardization of tool set-up parameters for environment in EUV lithography.

  6. Landfill Gas Control at Military Installations.

    DTIC Science & Technology

    1984-01-01

    Explosions or Fires 8 2 Composition of Municipal Solid Waste 10 3 Optimal Conditions for Anaerobic Decomposition 10 4 Variation Composition in a Typical...Composition of Municipal Solid Waste I I 4 Variation in Gas Production With Increasing Moisture Content 12 5 Variation in Carbon Dioxide and Methane...produces methane gas. Objective Municipal solid waste (MSW) is made up mostly (50 to The objective of this report is to provide any 80 percent) of

  7. Gas controller's paper pipeline - transportation and exchange

    SciTech Connect

    Chapman, R.E. Jr.

    1981-01-01

    When gas supplies began to decline during the 1970s, the US Federal Energy Regulatory Commission promulgated Orders 402 and 402-A to allow curtailed companies to make 60-day emergency purchases. In assisting its customer companies with such transactions, Texas Gas encountered several problems: the gas had to be allocated to each company, the sales required separate billing, the allocated volumes had to be received and delivered, and new contracts were necessary. Another stopgap measure, known as the 533 transportation service, also proved difficult to implement because the gas volumes were usually very small and were often interrupted when regular supplies began to resume. Under the Natural Gas Policy Act of 1978, interstate companies could offer the same gas prices to producers that intrastate companies paid; the NGPA also allowed sales from intra- to interstate companies. These provisions created a greater need for transportation-or-exchange service among all the parties. More recently, the FERC's Order 60 gave interstate companies the power to enter into self-implementing transportation-or-exchange service. Under legal modifications now being considered, pipeline companies will be able to significantly reduce regulatory delays by using blanket certificates.

  8. 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

  9. Development of gas chromatography analysis of fatty acids in marine organisms.

    PubMed

    Tang, Baokun; Row, Kyung Ho

    2013-08-01

    The gas chromatographic analysis of fatty acids has attracted considerable interest. In this analysis, the common derivatives of fatty acids, such as fatty acid methyl esters, can be detected using a flame ionization detector and the mass spectra can indicate the true structure of fatty acids. This paper reviews gas chromatographic methods for obtaining fatty acids from marine organisms. The stationary phase and detector for applications in gas chromatography are discussed. This article also reviews the components of fatty acids in marine animals, marine plants and marine microorganisms.

  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. Technological options for acid rain control

    SciTech Connect

    Princiotta, F.T.; Sedman, C.B.

    1993-01-01

    The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions. One key consideration is the effect of fuel switching or control technology upon the existing dust collector, with additional air toxics legislation looming ahead. A number of likely SO2 and NOx retrofit technologies and estimated costs are presented, along with results of retrofit case studies. New hybrid particulate controls are also being developed to meet future requirements.

  12. Dominant factors in controlling marine gas pools in South China

    USGS Publications Warehouse

    Xu, S.; Watney, W.L.

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up. ?? Higher Education Press and Springer-Verlag 2007.

  13. Gas-grain Modeling of Isocyanic Acid (HNCO), Cyanic Acid (HOCN), Fulminic Acid (HCNO), and Isofulminic Acid (HONC) in Assorted Interstellar Environments

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

  14. Gas chromatographic analysis of infant formulas for total fatty acids, including trans fatty acids.

    PubMed

    Satchithanandam, Subramaniam; Fritsche, Jan; Rader, Jeanne I

    2002-01-01

    Twelve powdered and 13 liquid infant formulas were analyzed by using an extension of AOAC Official Method 996.01 for fat analysis in cereal products. Samples were hydrolyzed with 8 N HCl and extracted with ethyl and petroleum ethers. Fatty acid methyl esters were prepared by refluxing the mixed ether extracts with methanolic sodium hydroxide in the presence of 14% boron trifluoride in methanol. The extracts were analyzed by gas chromatography. In powdered formulas, saturated fatty acid (SFA) content (mean +/- SD; n = 12) was 41.05 +/- 3.94%, monounsaturated fatty acid (MUFA) content was 36.97 +/- 3.38%, polyunsaturated fatty acid (PUFA) content was 20.07 +/- 3.08%, and total trans fatty acid content was 1.30 +/- 1.27%. In liquid formulas, SFA content (mean +/- SD; n = 13) was 42.29 +/- 2.98%, MUFA content was 36.05 +/- 2.47%, PUFA content was 20.65 +/- 2.40%, and total trans fatty acid content was 0.88 +/- 0.54%. Total fat content in powdered formulas ranged from 4.4 to 5.5 g/100 kcal and linoleic acid content ranged from 868 to 1166 mg/100 kcal. In liquid formulas, total fat content ranged from 4.1 to 5.1 g/100 kcal and linoleic acid content ranged from 820 to 1100 mg/100 kcal. There were no significant differences between powdered and liquid infant formulas in concentrations of total fat, SFA, MUFA, PUFA, or trans fatty acids.

  15. Emissions control for ground power gas turbines

    NASA Technical Reports Server (NTRS)

    Rudney, R. A.; Priem, R. J.; Juhasz, A. J.; Anderson, D. N.; Mroz, T. S.; Mularz, E. J.

    1977-01-01

    The similarities and differences of emissions reduction technology for aircraft and ground power gas turbines is described. The capability of this technology to reduce ground power emissions to meet existing and proposed emissions standards is presented and discussed. Those areas where the developing aircraft gas turbine technology may have direct application to ground power and those areas where the needed technology may be unique to the ground power mission are pointed out. Emissions reduction technology varying from simple combustor modifications to the use of advanced combustor concepts, such as catalysis, is described and discussed.

  16. Improved Controllers For Heaters In Toxic-Gas Combustors

    NASA Technical Reports Server (NTRS)

    Wishard, James; Lamb, James; Fortier, Edward; Velasquez, Hugo; Waltman, Doug

    1995-01-01

    Commercial electronic proportional controllers installed in place of mechanical power controllers for electric heaters in toxic-gas combustors at NASA's Jet Propulsion Laboratory. Designed to maintain temperature of heater at preset value by turning power fully on or fully off when temperature falls below or rises above that value, respectively. Solid-state power controllers overcome deficiencies of mechanical power controllers.

  17. Advanced sulfur control concepts for hot gas desulfurization technology

    SciTech Connect

    1998-09-01

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

  18. Controls on Gas Hydrate Formation and Dissociation

    SciTech Connect

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  19. Iron-control additives improve acidizing

    SciTech Connect

    Walker, M.; Dill, W. ); Besler, M. )

    1989-07-24

    Iron sulfide and sulfur precipitation in sour wells can be controlled with iron-sequestering agents and sulfide modifiers. Oil production has been routinely increased in sour wells where precipitation of iron sulfide and elemental sulfur has been brought under control. Production increases have been especially noteworthy on wells that had a history of rapid production decline after acid stimulation. Twenty-fold production increases have been recorded. Key to the production increase has been to increase permeability with: Iron chelating agents that control precipitation of iron sulfide. A sulfide modifier that reduces precipitation of solids in the presence of excessive amounts of hydrogen sulfide and prevents precipitation of elemental sulfur.

  20. Control of acid mine drainage using surfactants

    SciTech Connect

    Not Available

    1983-02-01

    This news sheet describes US Bureau of Mines work on the reduction or prevention of acid mine drainage from coal refuse piles and surface mines by inhibiting the growth of Thiobacillus ferrooxidans. It has been found that the direct application of a dilute surfactant or detergent solution to coal refuse piles or overburden can be an effective preventive measure or can reduce water treatment costs by controlling acid drainage at its source. Of the anionic surfactants tested to date, sodium lauryl sulphate appears to be the most effective. Alpha olefin sulphonate and alkyl benzene sulphonate are acceptable alternatives. The results of field trials are presented.

  1. 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.

  2. Buffered flue gas scrubbing system using adipic acid by-product stream

    SciTech Connect

    Lester, J.H. Jr.; Danly, D.E.

    1983-12-27

    A by-product stream from the production of adipic acid from cyclohexane, containing glutaric acid, succinic acid and adipic acid, is employed as a buffer in lime or limestone flue gas scrubbing for the removal of sulfur dioxide from combustion gases.

  3. Process gas chromatography study of a Selexol acid gas removal system. Final report Mar-Sep 82

    SciTech Connect

    Williams, W.A.

    1984-01-01

    The report gives results of continuous compositional monitoring by process gas chromatography (GC) for three gas streams associated with the Selexol acid gas removal system at the Bi-Gas pilot plant in Homer City, PA. Data were obtained from the inlet and outlet streams of the Selexol system during tests in April and May 1982. Product gas composition data were logged for 55 hours of plant operation. The Bi-Gas pilot plant, utilizing a two-stage, entrained-bed, high-pressure slagging gasifier, produces a product gas that is low in tars and heavy oils. This gas stream required very little cleanup prior to instrumental analysis. However, some problems were encountered in the analysis of the Selexol acid gas stream due to the presence of high levels of naphthalene. The process gas chromatographs performed well and remained very stable during the tests. Material balances based on GC analyses and process flow rate data show a high degree of material accountability. The H/sub 2/S removal efficiency of the Selexol absorber was about 99% during the tests.

  4. Gas cushion control of OVJP print head position

    SciTech Connect

    Forrest, Stephen R

    2014-10-07

    An OVJP apparatus and method for applying organic vapor or other flowable material to a substrate using a printing head mechanism in which the print head spacing from the substrate is controllable using a cushion of air or other gas applied between the print head and substrate. The print head is mounted for translational movement towards and away from the substrate and is biased toward the substrate by springs or other means. A gas cushion feed assembly supplies a gas under pressure between the print head and substrate which opposes the biasing of the print head toward the substrate so as to form a space between the print head and substrate. By controlling the pressure of gas supplied, the print head separation from the substrate can be precisely controlled.

  5. Solution and gas-phase acidities of all-trans (all-E) retinoic acid: an experimental and computational study.

    PubMed

    Abboud, José-Luis M; Koppel, Ilmar A; Uggerud, Einar; Leito, Ivo; Koppel, Ivar; Sekiguchi, Osamu; Kaupmees, Karl; Saame, Jaan; Kütt, Karl; Mishima, Masaaki

    2015-07-27

    Retinoic acid is of fundamental biological importance. Its acidity was determined in the gas phase and in acetonitrile solution by means of mass spectrometry and UV/Vis spectrophotometry, respectively. The intrinsic acidity is slightly higher than that of benzoic acid. In solution, the situation is opposite. The experimental systems were described theoretically applying quantum chemical methods (wave function theory and density functional theory). This allowed the determination of the molecular structure of the acid and its conjugate base, both in vacuo and in solution, and for computational estimates of its acidity in both phases.

  6. Control Decisions for Flammable Gas Hazards in Waste Transfer Systems

    SciTech Connect

    KRIPPS, L.J.

    2000-06-28

    This report describes the control decisions for flammable gas hazards in waste transfer systems (i.e., waste transfer piping and waste transfer-associated structures) made at control decision meetings on November 30, 1999a and April 19, 2000, and their basis. These control decisions, and the analyses that support them, will be documented in an amendment to the Final Safety Analysis Report (FSAR) (CHG 2000a) and Technical Safety Requirements (TSR) (CHG 2000b) to close the Flammable Gas Unreviewed Safety Question (USQ) (Bacon 1996 and Wagoner 1996). Following the Contractor Tier I review of the FSAR and TSR amendment, it will be submitted to the US. Department of Energy (DOE), Office of River Protection (ORP) for review and approval. The control decision meeting on November 30, 1999 to address flammable gas hazards in waste transfer systems followed the control decision process and the criteria for control decisions described in Section 3.3.1.5 of the FSAR. The control decision meeting agenda, attendance list, and introductory and background presentations are included in Attachments 1 through 4. The control decision discussions on existing and other possible controls for flammable gas hazards in waste transfer systems and the basis for selecting or not selecting specific controls are summarized in this report.

  7. Adipic acid enhanced limestone flue gas desulfurization process - an assessment

    SciTech Connect

    Mobley, J.D.; Chang, J.C.S.

    1981-12-01

    Adipic acid, when used as an additive in a limestone FGD system, greatly increases both SO/sub 2/ removal and limestone utilization. Most existing limestone scrubbers would benefit from adipic acid addition without major process changes. No significant operating problems or adverse environmental impacts have been identified. The adipic acid enhanced system is economically attractive. Waste dibasic acids and glycolic acid appear to provide benefits similar to adipic acid at a lower cost.

  8. Computer Control For Gas/Tungsten-Arc Welding

    NASA Technical Reports Server (NTRS)

    Andersen, Kristinn; Springfield, James F.; Barnett, Robert J.; Cook, George E.

    1994-01-01

    Prototype computer-based feedback control system developed for use in gas/tungsten arc welding. Beyond improving welding technician's moment-to-moment general control of welding process, control system designed to assist technician in selecting appropriate welding-process parameters, and provide better automatic voltage control. Modular for ease of reconfiguration and upgrading. Modularity also reflected in software. Includes rack-mounted computer, based on VME bus, containing Intel 80286 and 80386 processors.

  9. Utility flue gas mercury control via sorbent injection

    SciTech Connect

    Chang, R.; Carey, T.; Hargrove, B.

    1996-12-31

    The potential for power plant mercury control under Title III of the 1990 Clean Air Act Amendments generated significant interest in assessing whether cost effective technologies are available for removing the mercury present in fossil-fired power plant flue gas. One promising approach is the direct injection of mercury sorbents such as activated carbon into flue gas. This approach has been shown to be effective for mercury control from municipal waste incinerators. However, tests conducted to date on utility fossil-fired boilers show that it is much more difficult to remove the trace species of mercury present in flue gas. EPRI is conducting research in sorbent mercury control including bench-scale evaluation of mercury sorbent activity and capacity with simulated flue gas, pilot testing under actual flue gas conditions, evaluation of sorbent regeneration and recycle options, and the development of novel sorbents. A theoretical model that predicts maximum mercury removals achievable with sorbent injection under different operating conditions is also being developed. This paper presents initial bench-scale and model results. The results to date show that very fine and large amounts of sorbents are needed for mercury control unless long residence times are available for sorbent-mercury contact. Also, sorbent activity and capacity are highly dependent on flue gas composition, temperature, mercury species, and sorbent properties. 10 refs., 4 figs., 2 tabs.

  10. Gas turbine bucket wall thickness control

    DOEpatents

    Stathopoulos, Dimitrios; Xu, Liming; Lewis, Doyle C.

    2002-01-01

    A core for use in casting a turbine bucket including serpentine cooling passages is divided into two pieces including a leading edge core section and a trailing edge core section. Wall thicknesses at the leading edge and the trailing edge of the turbine bucket can be controlled independent of each other by separately positioning the leading edge core section and the trailing edge core section in the casting die. The controlled leading and trailing edge thicknesses can thus be optimized for efficient cooling, resulting in more efficient turbine operation.

  11. Gas compressor with side branch absorber for pulsation control

    SciTech Connect

    Harris, Ralph E.; Scrivner, Christine M.; Broerman, III, Eugene L.

    2011-05-24

    A method and system for reducing pulsation in lateral piping associated with a gas compressor system. A tunable side branch absorber (TSBA) is installed on the lateral piping. A pulsation sensor is placed in the lateral piping, to measure pulsation within the piping. The sensor output signals are delivered to a controller, which controls actuators that change the acoustic dimensions of the SBA.

  12. Etching radical controlled gas chopped deep reactive ion etching

    DOEpatents

    Olynick, Deidre; Rangelow, Ivo; Chao, Weilun

    2013-10-01

    A method for silicon micromachining techniques based on high aspect ratio reactive ion etching with gas chopping has been developed capable of producing essentially scallop-free, smooth, sidewall surfaces. The method uses precisely controlled, alternated (or chopped) gas flow of the etching and deposition gas precursors to produce a controllable sidewall passivation capable of high anisotropy. The dynamic control of sidewall passivation is achieved by carefully controlling fluorine radical presence with moderator gasses, such as CH.sub.4 and controlling the passivation rate and stoichiometry using a CF.sub.2 source. In this manner, sidewall polymer deposition thicknesses are very well controlled, reducing sidewall ripples to very small levels. By combining inductively coupled plasmas with controlled fluorocarbon chemistry, good control of vertical structures with very low sidewall roughness may be produced. Results show silicon features with an aspect ratio of 20:1 for 10 nm features with applicability to nano-applications in the sub-50 nm regime. By comparison, previous traditional gas chopping techniques have produced rippled or scalloped sidewalls in a range of 50 to 100 nm roughness.

  13. Geologic settings and controls of shallow gas, Rocky Mountain area

    SciTech Connect

    Rice, D.D. )

    1991-06-01

    Shallow gas is generated by the degradation of organic matter by anaerobic bacteria and is referred to as microbial or bacterial gas. Bacterial gas can be generated and can accumulate in significant quantities and is an important resource in the Rocky Mountain area. Factors controlling bacterial gas generation after sediment burial are anoxic conditions, low sulfate content, low temperatures, abundant organic matter, sufficient pore space, and rapid sediment deposition. Bacterial gas is distinguished by its chemical and isotopic composition; the hydrocarbon fraction generally contains more than 98% methane, and {delta}{sup 13}C{sub 1} values are generally lighter than {minus}55{per thousand}. In the Rocky Mountain area, bacterial gas accumulations occur in three main geologic settings: clastic shelves, carbonate shelves, and coal swamps. In the clastic shelf setting, bacterial gas occurs in thick (200 ft) sequences of sandstone, siltstone, and shale. The siltsone and sandstone occur as thin (a few inches thick), discontinuous lenses and laminae that serve as low-permeability reservoirs because of their small grain size. The enclosing shales are organic rich (average 2% total organic carbon (TOC)), contain type 3 kerogen, and serve as the source of and seal for the bacterial gas. The carbonate shelf setting is analogous to the clastic shelf with rythmically bedded couplets (a few inches thick) of low-permeability chalk (reservoir) and shale (source and seal). These shales are also organic rich (average 3.2% TOC) but contain type 2 kerogen. In the swamp setting, thick (as much as 200 ft), humic (type 3 kerogen) coal beds serve as both the source of and reservoir for the bacterial gas. The gas is trapped by the low porosity and permeability of coal and gas adsorption enhanced by hydrostatic pressure.

  14. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    1998-09-30

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H2S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct. The Direct Sulfur Recovery Process (DSRP), a leading process for producing an elemental sulfur byproduct in hot-gas desulfurization systems, incurs a coal gas use penalty, because coal gas is required to reduce the SO2 in regeneration off-gas to elemental sulfur. Alternative regeneration schemes, which avoid coal gas use and produce elemental sulfur, will be evaluated. These include (i) regeneration of sulfided sorbent using SO2 ; (ii) partial oxidation of sulfided sorbent in an O2 starved environment; and (iii) regeneration of sulfided sorbent using steam to produce H2S followed by direct oxidation of H2S to elemental sulfur. Known regenerable sorbents will be modified to improve the feasibility of the above alternative regeneration approaches. Performance characteristics of the modified sorbents and processes will be obtained through lab- and bench-scale testing. Technical and economic evaluation of the most promising processes concept(s) will be carried out.

  15. 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.

  16. Simultaneous determination of docosahexaenoic acid and eicosapentaenoic acid in common seafood using ultrasonic cell crusher extraction combined with gas chromatography.

    PubMed

    Zhao, Juanjuan; Ren, Yan; Yu, Chen; Chen, Xiangming; Shi, Yanan

    2017-02-01

    An effective method for the simultaneous determination of docosahexaenoic acid and eicosapentaenoic acid in common seafood by gas chromatography was developed and validated. Total docosahexaenoic acid and eicosapentaenoic acid were extracted from seafood by ultrasonic cell crusher assisted extraction and methyl esterified for gas chromatography analysis in the presence of the internal standard. The linearity was good (r > 0.999) in 9.59 ∼ 479.5 μg/mL for docosahexaenoic acid and 9.56 ∼ 477.8 μg/mL for eicosapentaenoic acid. The intrarun and interrun precisions were both within 4.8 and 6.1% for the two analytes, while the accuracy was less than 5.8%. The developed method was applied for determination of docosahexaenoic acid and eicosapentaenoic acid in six kinds of seafood. The result showed the content of docosahexaenoic acid and eicosapentaenoic acid was all higher than 1 mg/g in yellow croaker, hairtail, venerupis philippinarum, mussel, and oyster. Our work may be helpful for dietary optimization and production of docosahexaenoic acid and eicosapentaenoic acid.

  17. Virtual Instrumentation Corrosion Controller for Natural Gas Pipelines

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, J.; Agnihotri, G.; Deshpande, D. M.

    2012-12-01

    Corrosion is an electrochemical process. Corrosion in natural gas (methane) pipelines leads to leakages. Corrosion occurs when anode and cathode are connected through electrolyte. Rate of corrosion in metallic pipeline can be controlled by impressing current to it and thereby making it to act as cathode of corrosion cell. Technologically advanced and energy efficient corrosion controller is required to protect natural gas pipelines. Proposed virtual instrumentation (VI) based corrosion controller precisely controls the external corrosion in underground metallic pipelines, enhances its life and ensures safety. Designing and development of proportional-integral-differential (PID) corrosion controller using VI (LabVIEW) is carried out. When the designed controller is deployed at field, it maintains the pipe to soil potential (PSP) within safe operating limit and not entering into over/under protection zone. Horizontal deployment of this technique can be done to protect all metallic structure, oil pipelines, which need corrosion protection.

  18. CNG process, a new approach to physical-absorption acid-gas removal

    SciTech Connect

    Hise, R.E.; Massey, L.G.; Adler, R.J.; Brosilow, C.B.; Gardner, N.C.; Brown, W.R.; Cook, W.J.; Petrik, M.

    1982-01-01

    The CNG acid gas removal process embodies three novel features: (1) scrubbing with liquid carbon dioxide to remove all sulfurous molecules and other trace contaminants; (2) triple-point crystallization of carbon dioxide to concentrate sulfurous molecules and produce pure carbon dioxide; and (3) absorption of carbon dioxide with a slurry of solid carbon dioxide in organic carrier liquid. The CNG process is discussed and contrasted with existing acid gas removal technology as represented by the Benfield, Rectisol, and Selexol acid gas removal processes.

  19. Optimal Discrete Event Supervisory Control of Aircraft Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    Litt, Jonathan (Technical Monitor); Ray, Asok

    2004-01-01

    This report presents an application of the recently developed theory of optimal Discrete Event Supervisory (DES) control that is based on a signed real measure of regular languages. The DES control techniques are validated on an aircraft gas turbine engine simulation test bed. The test bed is implemented on a networked computer system in which two computers operate in the client-server mode. Several DES controllers have been tested for engine performance and reliability.

  20. Control of reactive oxygen and nitrogen species production in liquid by nonthermal plasma jet with controlled surrounding gas

    NASA Astrophysics Data System (ADS)

    Ito, Taiki; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Setsuhara, Yuichi

    2017-01-01

    We present the development of a low-frequency nonthermal plasma-jet system, where the surrounding-gas condition of the plasma jet is precisely controlled in open air. By restricting the mixing of the ambient air into the plasma jet, the plasma jet can be selectively changed from a N2 main discharge to an O2 main discharge even in open air. In the plasma-jet system with the controlled surrounding gas, the production of reactive oxygen and nitrogen species is successfully controlled in deionized water: the concentration ratio of NO2 - to H2O2 is tuned from 0 to 0.18, and a high NO2 - concentration ratio is obtained at a N2 gas ratio of 0.80 relative to the total N2/O2 gas mixture in the main discharge gas. We also find that the NO2 - concentration is much higher in the plasma-activated medium than in the plasma-activated deionized water, which is mainly explained by the contribution of amino acids to NO2 - generation in the medium.

  1. Vacuum rated flow controllers for inert gas ion engines

    NASA Technical Reports Server (NTRS)

    Pless, L. C.

    1987-01-01

    Electrical propulsion systems which use a gas as a propellant require a gas flowmeter/controller which is capable of operating in a vacuum environment. The presently available instruments in the required flow ranges are designed and calibrated for use at ambient pressure. These instruments operate by heating a small diameter tube through which the gas is flowing and then sensing the change in temperature along the length of the tube. This temperature change is a function of the flow rate and the gas heat capacity. When installed in a vacuum, the change in the external thermal characteristics cause the tube to overheat and the temperature sensors are then operating outside their calibrated range. In addition, the variation in heat capacity with temperature limit the accuracy obtainable. These problems and the work in progress to solve them are discussed.

  2. Editorial and Introduction of the Special Issue for the Ninth International Conference on Greenhouse Gas Control Technologies in the International Journal of Greenhouse Gas Control

    SciTech Connect

    Dooley, James J.; Benson, Sally M.; Karimjee, Anhar; Rubin, Edward S.

    2010-03-01

    Short one page editorial to introduce the +30 peer reviewed papers contained within the Special Issue for the Ninth International Conference on Greenhouse Gas Control Technologies in the International Journal of Greenhouse Gas Control

  3. Gas phase measurements of pyruvic acid and its volatile metabolites.

    PubMed

    Jardine, Kolby J; Sommer, Evan D; Saleska, Scott R; Huxman, Travis E; Harley, Peter C; Abrell, Leif

    2010-04-01

    Pyruvic acid, central to leaf carbon metabolism, is a precursor of many volatile organic compounds (VOCs) that impact air quality and climate. Although the pathways involved in the production of isoprenoids are well-known, those of several oxygenated VOCs remain uncertain. We present concentration and flux measurements of pyruvic acid and other VOCs within the tropical rainforest (TRF) biome at Biosphere 2. Pyruvic acid concentrations varied diurnally with midday maxima up to 15 ppbv, perhaps due to enhanced production rates and suppression of mitochondrial respiration in the light. Branch fluxes and ambient concentrations of pyruvic acid correlated with those of acetone, acetaldehyde, ethanol, acetic acid, isoprene, monoterpenes, and sesquiterpenes. While pyruvic acid is a known substrate for isoprenoid synthesis, this correlation suggests that the oxygenated VOCs may also derive from pyruvic acid, an idea supported by leaf feeding experiments with sodium pyruvate which resulted in large enhancements in emissions of both isoprenoids and oxygenated VOCs. While feeding with sodium pyruvate-2-(13)C resulted in large emissions of both (13)C-labeled isoprenoids and oxygenated VOCs, feeding with sodium pyruvate-1-(13)C resulted in only (13)C-labeled isoprenoids. This suggests that acetaldehyde, ethanol, and acetic acid are produced from pyruvic acid via the pyruvate dehydrogenase (PDH) bypass system (in which the 1-C carbon of pyruvic acid is lost as CO(2)) and that acetone is also derived from the decarboxylation of pyruvic acid.

  4. Alternative control techniques document: Nitric and adipic acid manufacturing plants

    SciTech Connect

    Lazzo, D.W.

    1991-12-01

    The Alternative Control Techniques document describes available control techniques for reducing NOx emission levels from nitric and adipic acid manufacturing plants. The document contains information on the formation of NOx and uncontrolled NOx emissions from nitric and adipic acid plants. The following NOx control techniques for nitric acid plants are discussed: extended absorption, nonselective catalytic reduction (NSCR), and selective catalytic reduction (SCR). The following NOx control techniques for adipic acid plants are discussed: extended absorption and thermal reduction. For each control technique, achievable controlled NOx emission levels, capital and annual costs, cost effectiveness, and environmental and energy impacts are presented.

  5. 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.

  6. Control System Design Language Implementation of a Gas Turbine Starting Controller.

    DTIC Science & Technology

    1984-06-01

    THESIS _ CONTROL SYSTEM DESIGN LANGUAGE IMPLEMENTATION OF A GAS TURBINE STARTING CONTROLLER by Richard Preston Riley June 1984 *1Thesis Advisor: A. A...CONTRACT OR GRANT NUM11101(s) Richard Preston Riley S. P01111SOMNM @R11ANS ATION NAME AND ADDRESS iG. PROGRAM ELEMENT. PROJECT. TASKAREA A WORKC UNIT...Design Language Implementation of a Gas Turbine Starting Controller by *J.4 Richard Preston Riley Lieutenant Commander, United States Navy B.S

  7. Survey and Analysis of Marine Gas Turbine Control After 1975

    DTIC Science & Technology

    1988-04-01

    the existing experimental data. Beginning in the early seventies, the U.S. Navy initiated The Gas Turbine Ship Propulsion Control Systems Research and...destroyers. Figure 1 shows a block diagram of the ship propulsion control system used. Simulations performed during the program tended to give good...Postgraduate school applied state space techniques to a linearized model of an FFG-7 ship propulsion system (5). Dynamic propulsion system equations were

  8. A Technique for Murine Irradiation in a Controlled Gas Environment

    PubMed Central

    Walb, M. C.; Moore, J. E.; Attia, A.; Wheeler, K. T.; Miller, M. S.; Munley, M. T.

    2013-01-01

    NASA’s extra-vehicular activities (EVAs) involve exposure to high energy photons while breathing 100% oxygen. Using previously verified mouse models, our laboratory is studying whether low dose irradiation under these hyperoxic conditions could lead to an increase in carcinogenic potential. To simulate the environment astronauts encounter during an EVA, enclosed chambers were constructed that allowed for mouse movement, controlled gas conditions, and uniform radiation dose delivery. Custom-built gas chambers with input/output gas valves and dividers that allowed for uniform gas flow were used to keep 6 unanesthetized mice separated while they were irradiated. The chambers were supplied with 100% oxygen or air using ball valves linked together with T-splitters. A calibrated ion chamber was used to verify the radiation dose distribution across an entire chamber. Mice were placed in the gas environments for 0.5 h, irradiated with a 10 or 18 MV photon beam from a medical linear accelerator, and left in their gas environment for 2 h post-irradiation. We irradiated 200 mice (5 different doses between 0–1000 mGy) under normoxic or 100% oxygen conditions. For the next step of this research, these mice will be euthanized 9 months post-irradiation, and lung tumors will be counted and sized to determine if hyperoxia increases the carcinogenic effect for this model. PMID:22846321

  9. Sand control in wells with gas generator and resin

    SciTech Connect

    Dees, J.M.

    1992-04-07

    This patent describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a quantity of fluid resin material in alignment with the formation perforations of the wellbore; positioning a gas generator in proximity with the fluid resin material; actuating the gas generator to increase wellbore pressure in a substantially instantaneous manner to a pressure substantially in excess of well pressure to force the fluid resin material from the wellbore into the formation perforations; and subsequently polymerizing the resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore. This paper also describes a method of treating a wellbore having formation perforations for controlling sand and other fine materials. It comprises positioning a coiled tubing, having a valve and gas generator attached thereto, so that the valve is positioned in a predetermined location relative to the bottom formation perforation; injecting a predetermined amount of fluid resin material through the coiled tubing and valve into the wellbore; raising the gas generator to a position across the formation perforations and in proximity with the fluid resin material; actuating the gas generator to force the fluid resin material into the formation perforations; and thereafter polymerizing the previously fluid resin material to form a consolidated, porous, permeable matrix which retains the sand and other fine materials while permitting the flow of production fluid into the wellbore.

  10. Mechanistic Processes Controlling Gas Sorption in Shale Reservoirs

    NASA Astrophysics Data System (ADS)

    Schaef, T.; Loring, J.; Ilton, E. S.; Davidson, C. L.; Owen, T.; Hoyt, D.; Glezakou, V. A.; McGrail, B. P.; Thompson, C.

    2014-12-01

    Utilization of CO2 to stimulate natural gas production in previously fractured shale-dominated reservoirs where CO2 remains in place for long-term storage may be an attractive new strategy for reducing the cost of managing anthropogenic CO2. A preliminary analysis of capacities and potential revenues in US shale plays suggests nearly 390 tcf in additional gas recovery may be possible via CO2 driven enhanced gas recovery. However, reservoir transmissivity properties, optimum gas recovery rates, and ultimate fate of CO2 vary among reservoirs, potentially increasing operational costs and environmental risks. In this paper, we identify key mechanisms controlling the sorption of CH4 and CO2 onto phyllosilicates and processes occurring in mixed gas systems that have the potential of impacting fluid transfer and CO2 storage in shale dominated formations. Through a unique set of in situ experimental techniques coupled with molecular-level simulations, we identify structural transformations occurring to clay minerals, optimal CO2/CH4 gas exchange conditions, and distinguish between adsorbed and intercalated gases in a mixed gas system. For example, based on in situ measurements with magic angle spinning NMR, intercalation of CO2 within the montmorillonite structure occurs in CH4/CO2 gas mixtures containing low concentrations (<5 mol%) of CO2. A stable montmorillonite structure dominates during exposure to pure CH4 (90 bar), but expands upon titration of small fractions (1-3 mol%) of CO2. Density functional theory was used to quantify the difference in sorption behavior between CO2 and CH4 and indicates complex interactions occurring between hydrated cations, CH4, and CO2. The authors will discuss potential impacts of these experimental results on CO2-based hydrocarbon recovery processes.

  11. Control of arc length during gas metal arc welding

    SciTech Connect

    Madigan, R.B.; Quinn, T.P.

    1994-12-31

    An arc-length control system has been developed for gas metal arc welding (GMAW) under spray transfer welding conditions. The ability to monitor and control arc length during arc welding allows consistent weld characteristics to be maintained and therefore improves weld quality. Arc length control has only been implemented for gas tungsten arc welding (GTAW), where an automatic voltage control (AVC) unit adjusts torch-to-work distance. The system developed here compliments the voltage- and current-sensing techniques commonly used for control of GMAW. The system consists of an arc light intensity sensor (photodiode), a Hall-effect current sensor, a personal computer and software implementing a data interpretation and control algorithms. Arc length was measured using both arc light and arc current signals. Welding current was adjusted to maintain constant arc length. A proportional-integral-derivative (PID) controller was used. Gains were automatically selected based on the desired welding conditions. In performance evaluation welds, arc length varied from 2.5 to 6.5 mm while welding up a sloped workpiece (ramp in CTWD) without the control. Arc length was maintained within 1 mm of the desired (5 mm ) with the control.

  12. Active Combustion Control for Aircraft Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

    2000-01-01

    Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

  13. 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.

  14. Selective transport of amino acids into the gas phase: driving forces for amino acid solubilization in gas-phase reverse micelles.

    PubMed

    Fang, Yigang; Bennett, Andrew; Liu, Jianbo

    2011-01-28

    We report a study on encapsulation of various amino acids into gas-phase sodium bis(2-ethylhexyl) sulfosuccinate (NaAOT) reverse micelles, using electrospray ionization guided-ion-beam tandem mass spectrometry. Collision-induced dissociation of mass-selected reverse micellar ions with Xe was performed to probe structures of gas-phase micellar assemblies, identify solute-surfactant interactions, and determine preferential incorporation sites of amino acids. Integration into gas-phase reverse micelles depends upon amino acid hydrophobicity and charge state. For examples, glycine and protonated amino acids (such as protonated tryptophan) are encapsulated within the micellar core via electrostatic interactions; while neutral tryptophan is adsorbed in the surfactant layer. As verified using model polar hydrophobic compounds, the hydrophobic effect and solute-interface hydrogen-bonding do not provide sufficient driving force needed for interfacial solubilization of neutral tryptophan. Neutral tryptophan, with a zwitterionic structure, is intercalated at the micellar interface between surfactant molecules through complementary effects of electrostatic interactions between tryptophan backbone and AOT polar heads, and hydrophobic interactions between tryptophan side chain and AOT alkyl tails. Protonation of tryptophan could significantly improve its incorporation capacity into gas-phase reverse micelles, and displace its incorporation site from the micellar interfacial zone to the core; protonation of glycine, on the other hand, has little effect on its encapsulation capacity. Another interesting observation is that amino acids of different isoelectric points could be selectively encapsulated into, and transported by, reverse micelles from solution to the gas phase, based upon their competition for protonation and subsequent encapsulation within the micellar core.

  15. Modelling and identification for control of gas bearings

    NASA Astrophysics Data System (ADS)

    Theisen, Lukas R. S.; Niemann, Hans H.; Santos, Ilmar F.; Galeazzi, Roberto; Blanke, Mogens

    2016-03-01

    Gas bearings are popular for their high speed capabilities, low friction and clean operation, but suffer from poor damping, which poses challenges for safe operation in presence of disturbances. Feedback control can achieve enhanced damping but requires low complexity models of the dominant dynamics over its entire operating range. Models from first principles are complex and sensitive to parameter uncertainty. This paper presents an experimental technique for "in situ" identification of a low complexity model of a rotor-bearing-actuator system and demonstrates identification over relevant ranges of rotational speed and gas injection pressure. This is obtained using parameter-varying linear models that are found to capture the dominant dynamics. The approach is shown to be easily applied and to suit subsequent control design. Based on the identified models, decentralised proportional control is designed and shown to obtain the required damping in theory and in a laboratory test rig.

  16. Industrial Raman gas sensing for real-time system control

    NASA Astrophysics Data System (ADS)

    Buric, M.; Mullen, J.; Chorpening, B.; Woodruff, S.

    2014-06-01

    Opportunities exist to improve on-line process control in energy applications with a fast, non-destructive measurement of gas composition. Here, we demonstrate a Raman sensing system which is capable of reporting the concentrations of numerous species simultaneously with sub-percent accuracy and sampling times below one-second for process control applications in energy or chemical production. The sensor is based upon a hollow-core capillary waveguide with a 300 micron bore with reflective thin-film metal and dielectric linings. The effect of using such a waveguide in a Raman process is to integrate Raman photons along the length of the sample-filled waveguide, thus permitting the acquisition of very large Raman signals for low-density gases in a short time. The resultant integrated Raman signals can then be used for quick and accurate analysis of a gaseous mixture. The sensor is currently being tested for energy applications such as coal gasification, turbine control, well-head monitoring for exploration or production, and non-conventional gas utilization. In conjunction with an ongoing commercialization effort, the researchers have recently completed two prototype instruments suitable for hazardous area operation and testing. Here, we report pre-commercialization testing of those field prototypes for control applications in gasification or similar processes. Results will be discussed with respect to accuracy, calibration requirements, gas sampling techniques, and possible control strategies of industrial significance.

  17. Cost analysis of NOx control alternatives for stationary gas turbines

    SciTech Connect

    Bill Major

    1999-11-05

    The use of stationary gas turbines for power generation has been growing rapidly with continuing trends predicted well into the future. Factors that are contributing to this growth include advances in turbine technology, operating and siting flexibility and low capital cost. Restructuring of the electric utility industry will provide new opportunities for on-site generation. In a competitive market, it maybe more cost effective to install small distributed generation units (like gas turbines) within the grid rather than constructing large power plants in remote locations with extensive transmission and distribution systems. For the customer, on-site generation will provide added reliability and leverage over the cost of purchased power One of the key issues that is addressed in virtually every gas turbine application is emissions, particularly NO{sub x} emissions. Decades of research and development have significantly reduced the NO{sub x} levels emitted from gas turbines from uncontrolled levels. Emission control technologies are continuing to evolve with older technologies being gradually phased-out while new technologies are being developed and commercialized. The objective of this study is to determine and compare the cost of NO{sub x} control technologies for three size ranges of stationary gas turbines: 5 MW, 25 MW and 150 MW. The purpose of the comparison is to evaluate the cost effectiveness and impact of each control technology as a function of turbine size. The NO{sub x} control technologies evaluated in this study include: Lean premix combustion, also known as dry low NO{sub x} (DLN) combustion; Catalytic combustion; Water/steam injection; Selective catalytic reduction (SCR)--low temperature, conventional, high temperature; and SCONO{sub x}{trademark}.

  18. Acid rain control: the costs of compliance

    SciTech Connect

    Gilleland, D.S.; Swisher, J.H.

    1985-01-01

    This document is the proceedings from a conference sponsored by the Illinois Energy Resources Commission and the Coal Extraction and Utilization Research Center, Southern Illinois University at Carbondale and held in Carbondale on March 18, 1984. Topics addressed include: the sources and impacts of acid rain, the problems inherent in modeling the impacts of acid rain legislation, the effects of acid rain legislation on the socio-economic sector, compliance costs, and the impact of acid rain legislation on related industries (railroads).

  19. Enhancement of mercury control in flue-gas cleanup systems

    SciTech Connect

    Livengood, C.D.; Huang, Hann S.; Mendelsohn, M.H.; Wu, Jiann M.

    1996-07-01

    This paper summarizes research at Argonne National Laboratory which is focused on techniques to enhance the capture of elemental mercury and integrate its control into existing flue-gas cleanup (FGC) systems. Both laboratory and field tests have shown that very little elemental mercury is captured in a wet scrubber system due to the low solubility of that species. To enhance the ability of wet scrubbers to capture mercury, Argonne has studied improved mass transfer through both mechanical and chemical means, as well as the conversion of elemental mercury into a more soluble species that can be easily absorbed. Current research is investigating the roles of several halogen species either alone or in combination with typical flue-gas components such as sulfur dioxide and nitric oxide in the oxidation of mercury to form compounds that are easily scrubbed from the flue gas.

  20. Femtosecond laser micromachining of aluminum surfaces under controlled gas atmospheres

    NASA Astrophysics Data System (ADS)

    Robinson, G. M.; Jackson, M. J.

    2006-04-01

    The interaction of 180 femtosecond (fs), 775 nm laser pulses with the surface of aluminum under controlled gas atmospheres at ambient pressure has been investigated to study material redeposition, residual surface roughness, and ablation rate. The effect of using various gases to protect the surface of the material appears to interfere with the effects of the plasma and can change the resulting microstructure of the machined surface. By varying the combinations of fluence and laser-scanning speed during ultrafast ablation at high repetition rates, an optimum micromachining condition can be reached, depending on the type of gas used during machining. The debris produced under certain laser-machining conditions tends to produce pure aluminum nanoparticles that are deposited very close to the machined feature by the gas used to protect the surface of the aluminum.

  1. Tectonic Controls on Gas Hydrate Distribution off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Berndt, C.; Chi, W. C.; Jegen, M. D.; Muff, S.; Hölz, S.; Lebas, E.; Sommer, M.; Lin, S.; Liu, C. S.; Lin, A. T.; Klaucke, I.; Klaeschen, D.; Chen, L.; Kunath, P.; McIntosh, K. D.; Feseker, T.

    2015-12-01

    The northern part of the South China Sea is characterized by wide-spread occurrence of bottom simulating reflectors (BSR), indicating the presence of marine gas hydrates. Because the area covers both the tectonically inactive passive margin and the northern termination of the Manila Trench subduction zone while sediment input is broadly similar, this area provides an excellent opportunity to study the influence of tectonic processes on the dynamics of gas hydrate systems. Long-offset multi-channel seismic data show that movement along thrust faults and blind thrust faults caused anticlinal ridges on the active margin, while faults are absent on the passive margin. This coincides with high-hydrate saturations derived from ocean bottom seismometer data and controlled source electromagnetic data, and conspicuous high-amplitude reflections in P-Cable 3D seismic data above the BSR in the anticlinal ridges of the active margin. On the contrary, all geophysical evidence for the passive margin points to normal- to low-hydrate saturations. Geochemical analysis of gas samples collected at seep sites on the active margin show methane with heavy δ13C isotope composition, while gas collected on the passive margin shows highly depleted (light) carbon isotope composition. Thus, we interpret the passive margin as a typical gas hydrate province fuelled by biogenic production of methane and the active margin gas hydrate system as a system that is fuelled not only by biogenic gas production but also by additional advection of thermogenic methane from the subduction system. The location of the highest gas hydrate saturations in the hanging wall next to the thrust faults suggests that the thrust faults represent pathways for the migration of methane. Our findings suggest that the most promising gas hydrate occurrences for exploitation of gas hydrate as an energy source may be found in the core of the active margin roll over anticlines immediately above the BSR and that high

  2. Adipic acid-enhanced limestone flue gas desulfurization system commercial demonstration. [Missouri

    SciTech Connect

    Hargrove, O.W. Jr.; Colley, J.D.; Mobley, J.D.

    1981-01-01

    A full-scale demonstration carried out at Springfield, Mo City Utilities Southwest Power Plant in 1980-1981 on adipic acid enhanced limestone flue gas desulfurization system is reported. The major process findings during the demonstration are discussed. It is found that adipic acid is a viable means for improving SO/sub 2/ removal in scrubbers which are limited from a dissolved alkalinity standpoint. Dibasic acid (a mixture of glutaric, adipic, and succinic acids) is a technically viable alternative to adipic acid. 6 refs.

  3. 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.

  4. Abscisic acid controlled sex before transpiration in vascular plants.

    PubMed

    McAdam, Scott A M; Brodribb, Timothy J; Banks, Jo Ann; Hedrich, Rainer; Atallah, Nadia M; Cai, Chao; Geringer, Michael A; Lind, Christof; Nichols, David S; Stachowski, Kye; Geiger, Dietmar; Sussmilch, Frances C

    2016-10-26

    Sexual reproduction in animals and plants shares common elements, including sperm and egg production, but unlike animals, little is known about the regulatory pathways that determine the sex of plants. Here we use mutants and gene silencing in a fern species to identify a core regulatory mechanism in plant sexual differentiation. A key player in fern sex differentiation is the phytohormone abscisic acid (ABA), which regulates the sex ratio of male to hermaphrodite tissues during the reproductive cycle. Our analysis shows that in the fern Ceratopteris richardii, a gene homologous to core ABA transduction genes in flowering plants [SNF1-related kinase2s (SnRK2s)] is primarily responsible for the hormonal control of sex determination. Furthermore, we provide evidence that this ABA-SnRK2 signaling pathway has transitioned from determining the sex of ferns to controlling seed dormancy in the earliest seed plants before being co-opted to control transpiration and CO2 exchange in derived seed plants. By tracing the evolutionary history of this ABA signaling pathway from plant reproduction through to its role in the global regulation of plant-atmosphere gas exchange during the last 450 million years, we highlight the extraordinary effect of the ABA-SnRK2 signaling pathway in plant evolution and vegetation function.

  5. The enormous apparent gas-phase acidity of cubylamine

    NASA Astrophysics Data System (ADS)

    Abboud, José-Luis M.; Alkorta, Ibon; Burk, Peeter; Dávalos, Juan Z.; Quintanilla, Esther; Della, Ernest W.; Koppel, Ilmar A.; Koppel, Ivar

    2004-11-01

    The high acidity of cubylamine ( 1NH 2) seems to originate in the release of strain energy attending the breaking of some C-C bonds in 1NH -. This process is greatly facilitated by the strong stereoelectronic interactions in 1NH -. The anionic species thus formed are less strained, and their corresponding conjugate acids seem unable to 'borrow strength' from the residual strain, at least within the time-scale of the FT ICR experiments.

  6. Mineralogical transformations controlling acid mine drainage chemistry

    SciTech Connect

    Peretyazhko, Tetyana; Zachara, John M.; Boily, Jean F.; Xia, Yuanxian; Gassman, Paul L.; Arey, Bruce W.; Burgos, William D.

    2009-05-30

    The role of Fe(III) minerals in controlling acid mine drainage (AMD) chemistry was studied using samples from two AMD sites [Gum Boot (GB) and Fridays-2 (FR)] located in northern Pennsylvania. Chemical extractions, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to identify and characterize Fe(III) phases. The mineralogical analysis revealed that schwertmannite and goethite were the principal Fe(III) phases in the sediments. Schwertmannite transformation occurred at the GB site where poorly-crystallized goethite rich in surface-bound sulfate was initially formed. In contrast, no schwertmannite transformation occurred at the FR site. The goethite in GB sediments had spherical morphology due to preservation of schwertmannite structure by adsorbed sulfate. Results of chemical extractions showed that poorly-crystallized goethite was subject to further crystallization accompanied by sulfate desorption. Changes in sulfate speciation preceded its desorption, with a conversion of bidentate- to monodentate-bound sulfate surface complexes. Laboratory sediment incubation experiments were conducted to evaluate the effect of mineral transformation on water chemistry. Incubation experiments were carried out with schwertmannite-containing sediments and AMD waters with different pH and chemical composition. The pH decreased to 1.9-2.2 in all suspensions and the concentrations of dissolved Fe and S increased significantly. Regardless of differences in the initial water composition, pH, Fe and S were similar in suspensions of the same sediment. XRD measurements revealed that schwertmannite transformed into goethite in GB and FR sediments during laboratory incubation. The incubation experiment demonstrated that schwertmannite transformation controlled AMD water chemistry during “closed system” laboratory contact.

  7. An Effective Acid Combination for Enhanced Properties and Corrosion Control of Acidizing Sandstone Formation

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham

    2016-03-01

    To fulfill the demand of the world energy, more technologies to enhance the recovery of oil production are being developed. Sandstone acidizing has been introduced and it acts as one of the important means to increase oil and gas production. Sandstone acidizing operation generally uses acids, which create or enlarge the flow channels of formation around the wellbore. In sandstone matrix acidizing, acids are injected into the formation at a pressure below the formation fracturing pressure, in which the injected acids react with mineral particles that may restrict the flow of hydrocarbons. Most common combination is Hydrofluoric Acid - Hydrochloric with concentration (3% HF - 12% HCl) known as mud acid. But there are some problems associated with the use of mud acid i.e., corrosion, precipitation. In this paper several new combinations of acids were experimentally screened to identify the most effective combination. The combinations used consist of fluoboric, phosphoric, formic and hydrofluoric acids. Cores were allowed to react with these combinations and results are compared with the mud acid. The parameters, which are analyzed, are Improved Permeability Ratio, strength and mineralogy. The analysis showed that the new acid combination has the potential to be used in sandstone acidizing.

  8. Determination of selected fatty acids in dried sweat spot using gas chromatography with flame ionization detection.

    PubMed

    Kanďár, Roman; Drábková, Petra; Andrlová, Lenka; Kostelník, Adam; Čegan, Alexander

    2016-11-01

    A method is described for the determination of fatty acids in dried sweat spot and plasma samples using gas chromatography with flame ionization detection. Plasma and dried sweat spot samples were obtained from a group of blood donors. The sweat was collected from each volunteer during exercise. Sweat was spotted onto collection paper containing butylated hydroxytoluene. Fatty acids were derivatized with acetyl chloride in methanol to form methyl esters of fatty acids. The fatty acids in dried sweat spot samples treated with butylated hydroxytoluene and stored at -20°C were stable for 3 months. Our results indicate that sweat contains, among fatty acids with short chain, also fatty acids with long chain and unsaturated fatty acids. Linear relationships between percentage content of selected fatty acids in dried sweat spot and plasma were observed.

  9. Deflagration-to-Detonation Transition Control by Nanosecond Gas Discharges

    DTIC Science & Technology

    2008-04-07

    Report 3. DATES COVERED (From – To) 1 April 2007 - 18 August 09 4. TITLE AND SUBTITLE Deflagration-To- Detonation Transition Control By Nanosecond...SUPPLEMENTARY NOTES 14. ABSTRACT During the current project, an extensive experimental study of detonation initiation by high{voltage...nanosecond gas discharges has been performed in a smooth detonation tube with different discharge chambers and various discharge cell numbers. The chambers

  10. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, J.R.; Dodson, M.G.

    1999-05-25

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846. 8 figs.

  11. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, James R.; Dodson, Michael G.

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

  12. 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.

  13. 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.

  14. 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.

  15. Controlled pilot oxidizer for a gas turbine combustor

    DOEpatents

    Laster, Walter R.; Bandaru, Ramarao V.

    2010-07-13

    A combustor (22) for a gas turbine (10) includes a main burner oxidizer flow path (34) delivering a first portion (32) of an oxidizer flow (e.g., 16) to a main burner (28) of the combustor and a pilot oxidizer flow path (38) delivering a second portion (36) of the oxidizer flow to a pilot (30) of the combustor. The combustor also includes a flow controller (42) disposed in the pilot oxidizer flow path for controlling an amount of the second portion delivered to the pilot.

  16. 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...

  17. FGD improves with adipic acid. [Flue gas desulfurization

    SciTech Connect

    Catalano, L.

    1982-07-01

    The addition of adipic acid to the limestone slurry in wet-scrubbing systems has been shown to enhance SO/sub 2/ collection and limestone utilisation whilst reducing operating costs. The results of demonstration tests carried out for the EPA on utility and industrial plants are presented.

  18. 40 CFR 80.33 - Controls applicable to natural gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Controls applicable to natural gas... Prohibitions § 80.33 Controls applicable to natural gas retailers and wholesale purchaser-consumers. (a) After... feet of natural gas per month shall equip each pump from which natural gas is introduced into...

  19. 40 CFR 80.33 - Controls applicable to natural gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Controls applicable to natural gas... Prohibitions § 80.33 Controls applicable to natural gas retailers and wholesale purchaser-consumers. (a) After... feet of natural gas per month shall equip each pump from which natural gas is introduced into...

  20. Empirical Modeling of Plant Gas Fluxes in Controlled Environments

    NASA Technical Reports Server (NTRS)

    Cornett, Jessie David

    1994-01-01

    As humans extend their reach beyond the earth, bioregenerative life support systems must replace the resupply and physical/chemical systems now used. The Controlled Ecological Life Support System (CELSS) will utilize plants to recycle the carbon dioxide (CO2) and excrement produced by humans and return oxygen (O2), purified water and food. CELSS design requires knowledge of gas flux levels for net photosynthesis (PS(sub n)), dark respiration (R(sub d)) and evapotranspiration (ET). Full season gas flux data regarding these processes for wheat (Triticum aestivum), soybean (Glycine max) and rice (Oryza sativa) from published sources were used to develop empirical models. Univariate models relating crop age (days after planting) and gas flux were fit by simple regression. Models are either high order (5th to 8th) or more complex polynomials whose curves describe crop development characteristics. The models provide good estimates of gas flux maxima, but are of limited utility. To broaden the applicability, data were transformed to dimensionless or correlation formats and, again, fit by regression. Polynomials, similar to those in the initial effort, were selected as the most appropriate models. These models indicate that, within a cultivar, gas flux patterns appear remarkably similar prior to maximum flux, but exhibit considerable variation beyond this point. This suggests that more broadly applicable models of plant gas flux are feasible, but univariate models defining gas flux as a function of crop age are too simplistic. Multivariate models using CO2 and crop age were fit for PS(sub n), and R(sub d) by multiple regression. In each case, the selected model is a subset of a full third order model with all possible interactions. These models are improvements over the univariate models because they incorporate more than the single factor, crop age, as the primary variable governing gas flux. They are still limited, however, by their reliance on the other environmental

  1. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  2. 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

  3. Control of bovine hepatic fatty acid oxidation

    SciTech Connect

    Jesse, B.W.; Emery, R.S.; Thomas, J.W.

    1986-09-01

    Fatty acid oxidation by bovine liver slices and mitochondria was examined to determine potential regulatory sites of fatty acid oxidation. Conversion of 1-(/sup 14/C)palmitate to /sup 14/CO/sub 2/ and total (/sup 14/C)acid-soluble metabolites was used to measure fatty acid oxidation. Oxidation of palmitate (1 mM) was linear in both liver slice weight and incubation time. Carnitine stimulated palmitate oxidation; 2 mM dl-carnitine produced maximal stimulation of palmitate oxidation to both CO/sup 2/ and acid-soluble metabolites. Propionate (10 mM) inhibited palmitate oxidation by bovine liver slices. Propionate (.5 to 10 mM) had no effect on palmitate oxidation by mitochondria, but malonyl Coenzyme A, the first committed intermediate of fatty acid synthesis, inhibited mitochondrial palmitate oxidation (inhibition constant = .3 ..mu..M). Liver mitochonndrial carnitine palmitoyltransferase exhibited Michaelis constants for palmitoyl Coenzyme A and l-carnitine of 11.5 ..mu..M and .59 mM, respectively. Long-chain fatty acid oxidation in bovine liver is regulated by mechanisms similar to those in rats but adapted to the unique digestive physiology of the bovine.

  4. Flue gas desulfurization by-products additions to acid soil: alfalfa productivity and environmental quality.

    PubMed

    Chen, L; Dick, W A; Nelson, S

    2001-01-01

    Flue gas desulfurization (FGD) by-products are created when coal is burned and SO2 is removed from the flue gases. These FGD by-products are often alkaline and contain many plant nutrients. Land application of FGD by-products is encouraged but little information is available related to plant responses and environmental impacts concerning such use. Agricultural lime (ag-lime) and several new types of FGD by-products which contain either vermiculite or perlite were applied at 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) rate to an acidic soil (Wooster silt loam). The highest FGD by-products application rate was equivalent to 75.2 Mg ha(-1). Growth of alfalfa (Medicago sativa L.) was significantly increased compared to the untreated control in the second year after treatment with yields for the 1 x LR rate of FGD approximately 7-8 times greater compared to the untreated control and 30% greater than for the commercial ag-lime. Concentrations of Mo in alfalfa were significantly increased by FGD by-products application, compared to the untreated control, while compared to the ag-lime treatment, concentrations of B increased and Ba decreased. No soil contamination problems were observed, even at the 2xLR rate, indicating these materials can be safely applied to agricultural soils.

  5. Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

    PubMed

    Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

    2017-02-17

    This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control.

  6. 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).

  7. 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).

  8. Formose reaction controlled by boronic acid compounds

    PubMed Central

    Imai, Toru; Michitaka, Tomohiro

    2016-01-01

    Formose reactions were carried out in the presence of low molecular weight and macromolecular boronic acid compounds, i.e., sodium phenylboronate (SPB) and a copolymer of sodium 4-vinylphenylboronate with sodium 4-styrenesulfonate (pVPB/NaSS), respectively. The boronic acid compounds provided different selectivities; sugars of a small carbon number were formed favorably in the presence of SPB, whereas sugar alcohols of a larger carbon number were formed preferably in the presence of pVPB/NaSS. PMID:28144337

  9. Quantification and Controls of Wetland Greenhouse Gas Emissions

    SciTech Connect

    McNicol, Gavin

    2016-05-10

    Wetlands cover only a small fraction of the Earth’s land surface, but have a disproportionately large influence on global climate. Low oxygen conditions in wetland soils slows down decomposition, leading to net carbon dioxide sequestration over long timescales, while also favoring the production of redox sensitive gases such as nitrous oxide and methane. Freshwater marshes in particular sustain large exchanges of greenhouse gases under temperate or tropical climates and favorable nutrient regimes, yet have rarely been studied, leading to poor constraints on the magnitude of marsh gas sources, and the biogeochemical drivers of flux variability. The Sacramento-San Joaquin Delta in California was once a great expanse of tidal and freshwater marshes but underwent drainage for agriculture during the last two centuries. The resulting landscape is unsustainable with extreme rates of land subsidence and oxidation of peat soils lowering the surface elevation of much of the Delta below sea level. Wetland restoration has been proposed as a means to slow further subsidence and rebuild peat however the balance of greenhouse gas exchange in these novel ecosystems is still poorly described. In this dissertation I first explore oxygen availability as a control on the composition and magnitude of greenhouse gas emissions from drained wetland soils. In two separate experiments I quantify both the temporal dynamics of greenhouse gas emission and the kinetic sensitivity of gas production to a wide range of oxygen concentrations. This work demonstrated the very high sensitivity of carbon dioxide, methane, and nitrous oxide production to oxygen availability, in carbon rich wetland soils. I also found the temporal dynamics of gas production to follow a sequence predicted by thermodynamics and observed spatially in other soil or sediment systems. In the latter part of my dissertation I conduct two field studies to quantify greenhouse gas exchange and understand the carbon sources for

  10. CNG acid gas removal process. Technical progress report No. 5, November 1, 1981-January 31, 1982

    SciTech Connect

    Adler, R.J.; Auyang, L.; Brown, W.R.; Cook, W.J.; Liu, Y.C.; Petrik, M.

    1982-11-01

    Three tasks were active during the fifth quarter of the CNG Acid Gas Removal project: Subtask 1.3 design and construction of a bench-scale triple-point crystallizer; Subtask 2.4 slurry pumping; and Task 4 fate of trace components. Within Subtask 1.3, safety considerations for the present CNG triple-point crystallizer system are summarized. These include: (1) building safety features, (2) crystallizer safety features, and (3) personnel safety features. Within Subtask 2.4, the minimum net positive suction head required for a MicroPump gear pump to successfully pump slurries of solid carbon dioxide in an organic liquid carrier solvent has been determined. Task 4, determination of the fate of trace contaminants in the CNG acid gas removal process, is complete. Trace contaminants anticipated in the crude gas entering acid gas removal are removed to acceptably low levels by the CNG process and rejected with the acid gases. With the possible exception of benzene, no recycle loops or accumulation of contaminants occur in the CNG process. Combinations of feed gas pressure and benzene contamination which may cause deposition of solid benzene are defined. 21 references, 10 figures, 6 tables.

  11. Organic acids enhanced decoloration of azo dye in gas phase surface discharge plasma system.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-01-25

    A gas phase surface discharge plasma combined with organic acids system was developed to enhance active species mass transfer and dye-containing wastewater treatment efficacy, with Acid Orange II (AO7) as the model pollutant. The effects of discharge voltage and various organic acid additives (acetic acid, lactic acid and nonoic acid) on AO7 decoloration efficiency were evaluated. The experimental results showed that an AO7 decoloration efficiency of approximately 69.0% was obtained within 4 min of discharge plasma treatment without organic acid addition, which was improved to 82.8%, 83.5% and 88.6% within the same treatment time with the addition of acetic acid, lactic acid and nonoic acid, respectively. The enhancement effects on AO7 decoloration efficiency could be attributed to the decrease in aqueous surface tension, improvement in bubble distribution and shape, and increase in ozone equivalent concentration. The AO7 wastewater was biodegradable after discharge plasma treatment with the addition of organic acid. AO7 decomposition intermediates were analyzed by UV-vis spectrometry and GC-MS; 2-naphthol, 1,4-benzoquinone, phthalic anhydride, coumarin, 1,2-naphthoquinone, and 2-formyl-benzoic acid were detected. A possible pathway for AO7 decomposition in this system was proposed.

  12. Amino acid auxotrophy as a system of immunological control nodes.

    PubMed

    Murray, Peter J

    2016-02-01

    Cells of the immune system are auxotrophs for most amino acids, including several nonessential ones. Arginine and tryptophan are used within the regulatory immune networks to control proliferation and function through pathways that actively deplete the amino acid from the microenvironment or that create regulatory molecules such as nitric oxide or kynurenines. How immune cells integrate information about essential amino acid supplies and then transfer these signals to growth and activation pathways remains unclear but has potential for pathway discovery about amino sensing. In applied research, strategies to harness amino acid auxotrophy so as to block cancerous lymphocyte growth have been attempted for decades with limited success. Emerging insights about amino acid metabolism may lead to new strategies in clinical medicine whereby both amino acid auxotrophy and the immunoregulatory pathways controlled by amino acids can be manipulated.

  13. Quantitative gas chromatographic analysis of volatile fatty acids in spent culture media and body fluids.

    PubMed Central

    van den Bogaard, A E; Hazen, M J; Van Boven, C P

    1986-01-01

    Gas chromatographic analysis of volatile fatty acids for identification of obligately anaerobic bacteria and for presumptive diagnosis of anaerobic infections is now widely practiced. However, it is difficult to compare data because only a qualitative analysis is done or only chromatograms are presented instead of quantitative data on volatile fatty acid production. We compared three stationary phases for volatile fatty acid analysis of aqueous solutions and four methods of pretreating samples for gas chromatography. Quantitative analysis could be done accurately by using Carbowax as the stationary phase after pretreatment of spent culture media with Dowex columns. If only qualitative analysis is required (e.g., for presumptive diagnosis of anaerobic infections), ether extraction and headspace analysis are equally suitable. The overall variation coefficient for volatile fatty acid production by four reference strains of obligately anaerobic bacteria after 24 h of incubation was approximately 10%. PMID:3958144

  14. Gas-phase acidities of tetrahedral oxyacids from ab initio electronic structure theory

    SciTech Connect

    Rustad, J.R.; Dixon, D.A.; Kubicki, J.D.; Felmy, A.R.

    2000-05-04

    Density functional calculations have been performed on several protonation states of the oxyacids of Si, P, V, As, Cr, and S. Structures and vibrational frequencies are in good agreement with experimental values where these are available. A reasonably well-defined correlation between the calculated gas-phase acidities and the measured pK{sub a} in aqueous solution has been found. The pK{sub a}/gas-phase acidity slopes are consistent with those derived from previous molecular mechanics calculations on ferric hydrolysis and the first two acidity constants for orthosilicic acid. The successive deprotonation of other H{sub n}TO{sub 4} species, for a given tetrahedral anion T are roughly consistent with this slope, but not to the extent that there is a universal correlation among all species.

  15. A control system for maintaining high stability in gas pressure

    SciTech Connect

    Wuest, C.R.; Hendricks, C.D.

    1987-09-01

    A pressure control system has been implemented on an experiment designed to detect the presence of fractional charges in bulk matter. The experiment utilizes a liquid-droplet generation technique requiring high-stability gas-pressure delivery to ensure accurate data collection. The pressure control system consists of a pressurized mercury reservoir containing a low-vapor-pressure, diffusion-pump oil. A commercially available differential pressure transducer, servo-driven valve, and controller sense the pressure fluctuations with respect to a static reference pressure. The system can maintain constant pressure to better than one part in 10,000 at working pressures in the range of 100 to 300 psi. 3 refs., 7 figs.

  16. Apparatus and method for gas turbine active combustion control system

    NASA Technical Reports Server (NTRS)

    Umeh, Chukwueloka (Inventor); Kammer, Leonardo C. (Inventor); Shah, Minesh (Inventor); Fortin, Jeffrey B. (Inventor); Knobloch, Aaron (Inventor); Myers, William J. (Inventor); Mancini, Alfred Albert (Inventor)

    2011-01-01

    An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

  17. Determination of free fatty acids and triglycerides by gas chromatography using selective esterification reactions.

    PubMed

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

    2012-01-01

    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.

  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. Methods of Si based ceramic components volatilization control in a gas turbine engine

    SciTech Connect

    Garcia-Crespo, Andres Jose; Delvaux, John; Dion Ouellet, Noemie

    2016-09-06

    A method of controlling volatilization of silicon based components in a gas turbine engine includes measuring, estimating and/or predicting a variable related to operation of the gas turbine engine; correlating the variable to determine an amount of silicon to control volatilization of the silicon based components in the gas turbine engine; and injecting silicon into the gas turbine engine to control volatilization of the silicon based components. A gas turbine with a compressor, combustion system, turbine section and silicon injection system may be controlled by a controller that implements the control method.

  20. 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.

  1. Unconventional mechanisms control cyclic respiratory gas release in flying Drosophila.

    PubMed

    Lehmann, Fritz-Olaf; Heymann, Nicole

    2005-10-01

    The high power output of flight muscles places special demands on the respiratory gas exchange system in insects. In small insects, respiration relies on diffusion, and for elevated locomotor performance such as flight, instantaneous gas exchange rates typically co-vary with the animal's metabolic activity. By contrast, under certain conditions, instantaneous release rate of carbon dioxide from the fruit fly Drosophila flying in a virtual-reality flight arena may oscillate distinctly at low frequency (0.37+/-0.055 Hz), even though flight muscle mechanical power output requires constant metabolic activity. Cross-correlation analysis suggests that this uncoupling between respiratory and metabolic rate is not driven by conventional types of convective flow reinforcement such as abdominal pumping, but might result from two unusual mechanisms for tracheal breathing. Simplified analytical modeling of diffusive tracheal gas exchange suggests that cyclic release patterns in the insect occur as a consequence of the stochastically synchronized control of spiracle opening area by the four large thoracic spiracles. Alternatively, in-flight motion analysis of the abdomen and proboscis using infra-red video imaging suggests utilization of the proboscis extension reflex (PER) for tracheal convection. Although the respiratory benefit of synchronized spiracle opening activity in the fruit fly is unclear, proboscis-induced tracheal convection might potentially help to balance the local oxygen supply between different body compartments of the flying animal.

  2. 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.

  3. Fuel control for gas turbine with continuous pilot flame

    DOEpatents

    Swick, Robert M.

    1983-01-01

    An improved fuel control for a gas turbine engine having a continuous pilot flame and a fuel distribution system including a pump drawing fuel from a source and supplying a line to the main fuel nozzle of the engine, the improvement being a control loop between the pump outlet and the pump inlet to bypass fuel, an electronically controlled throttle valve to restrict flow in the control loop when main nozzle demand exists and to permit substantially unrestricted flow without main nozzle demand, a minimum flow valve in the control loop downstream of the throttle valve to maintain a minimum pressure in the loop ahead of the flow valve, a branch tube from the pilot flame nozzle to the control loop between the throttle valve and the minimum flow valve, an orifice in the branch tube, and a feedback tube from the branch tube downstream of the orifice to the minimum flow valve, the minimum flow valve being operative to maintain a substantially constant pressure differential across the orifice to maintain constant fuel flow to the pilot flame nozzle.

  4. Controllability analysis and decentralized control of a wet limestone flue gas desulfurization plant

    SciTech Connect

    Perales, A.L.V.; Ortiz, F.J.G.; Ollero, P.; Gil, F.M.

    2008-12-15

    Presently, decentralized feedback control is the only control strategy used in wet limestone flue gas desulfurization (WLFGD) plants. Proper tuning of this control strategy is becoming an important issue in WLFGD plants because more stringent SO{sub 2} regulations have come into force recently. Controllability analysis is a highly valuable tool for proper design of control systems, but it has not been applied to WLFGD plants so far. In this paper a decentralized control strategy is designed and applied to a WLFGD pilot plant taking into account the conclusions of a controllability analysis. The results reveal that good SO{sub 2} control in WLFGD plants can be achieved mainly because the main disturbance of the process is well-aligned with the plant and interactions between control loops are beneficial to SO{sub 2} control.

  5. Haematological, blood gas and acid-base effects of central histamine-induced reversal of critical haemorrhagic hypotension in rats.

    PubMed

    Jochem, J

    2001-09-01

    In a rat model of volume-controlled irreversible haemorrhagic shock, which results in a severe metabolic acidosis and the death of all control animals within 30 min., intracerebroventricular injection of histamine (100 nmol) produces a prompt and long-lasting increase in mean arterial pressure and heart rate, with a 100% survival of 2 h after treatment. Histamine action is accompanied by a decrease in haematocrit value, haemoglobin concentration, erythrocyte and platelet count, and an increase in residual blood volume at the end of the experiment (2 h). Cardiovascular effects are also associated with a long-lasting rise in respiratory rate and biphasic blood acid-base changes - initial increase of metabolic acidosis with the decrease in arterial and venous pH, bicarbonate concentration and base excess, followed by almost a complete recovery of blood gas and acid-base parameters to the pre-bleeding values, with normalisation of arterial and venous pH, Pco2 bicarbonate concentration and base excess at the end of experiment. It can be concluded that in the late phase of central histamine-induced reversal of haemorrhagic hypotension there is almost a complete restoration of blood gas and acid-base status due to circulatory and respiratory compensations, while accompanying haematological changes are the result of the haemodilution and the increase in residual blood volume.

  6. The detection properties of ammonia SAW gas sensors based on L-glutamic acid hydrochloride.

    PubMed

    Shen, Chi-Yen; Huang, Chun-Pu; Huang, Wang-Tsung

    2005-10-01

    This study has investigated an improved surface acoustic wave (SAW) ammonia gas sensor based on L-glutamic acid hydrochloride. It presents an excellent reversibility, sensitivity, and repeatability to ammonia. The frequency shift versus ammonia concentration above 40 degrees C was a monotonic function, and the limit of detection of the sensor at 50 degrees C was 80 ppb.

  7. 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

  8. 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

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

    DOEpatents

    Rau, Gregory Hudson [Castro Valley, CA

    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.

  10. Control of stability and structure of nucleic acids using cosolutes.

    PubMed

    Tateishi-Karimta, Hisae; Sugimoto, Naoki

    2014-05-15

    The stabilities, structures, and functions of nucleic acids are responsive to surrounding conditions. Living cells contain biomolecules, including nucleic acids, proteins, polysaccharides, and other soluble and insoluble low-molecular weight components, that occupy a significant fraction of the cellular volume (up to 40%), resulting in a highly crowded intracellular environment. We have proven that conditions that mimic features of this intra-cellular environment alter the physical properties affect the stability, structure, and function of nucleic acids. The ability to control structure of nucleic acids by mimicking intra-cellular conditions will be useful in nanotechnology applications of nucleic acids. This paper describes methods that can be used to analyze quantitatively the intra-cellular environment effects caused by cosolutes on nucleic acid structures and to regulate properties of nucleic acids using cosolutes.

  11. Gas-phase reactivity of carboxylic acid functional groups with carbodiimides.

    PubMed

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

    2013-01-01

    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.

  12. 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.

  13. Scythe (pelargonic acid) weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and y...

  14. Monte Carlo simulations of the pressure dependence of the water-acid gas interfacial tensions.

    PubMed

    Biscay, F; Ghoufi, A; Lachet, V; Malfreyt, P

    2009-10-29

    We report two-phase Monte Carlo (MC) simulations of the binary water-acid gas mixtures at high temperature and high pressure. Simulations are performed in the Np(N)AT ensemble in order to reproduce the pressure dependence of the interfacial tensions of the water-CO(2) and water-H(2)S mixtures. The interfacial tension of the binary water-CO(2) mixture is determined from 5 to 45 MPa along the isotherm T = 383 K. Water-H(2)S interfacial tensions are computed along one supercritical isotherm (T = 393 K) in a pressure range of 1-15 MPa. The temperature and pressure conditions investigated here by the MC simulations are typical of the geological storage conditions of these acid gases. The coexisting densities and the compositions of the water-rich and acid-gas-rich phases are compared with experiments and with data calculated from Gibbs ensemble Monte Carlo (GEMC) simulations.

  15. 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.

  16. Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

    PubMed

    Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

    2016-12-01

    Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA12, GA19, GA20 and GA8) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides.

  17. Neural net controlled tag gas sampling system for nuclear reactors

    DOEpatents

    Gross, Kenneth C.; Laug, Matthew T.; Lambert, John D. B.; Herzog, James P.

    1997-01-01

    A method and system for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod.

  18. Neural net controlled tag gas sampling system for nuclear reactors

    DOEpatents

    Gross, K.C.; Laug, M.T.; Lambert, J.B.; Herzog, J.P.

    1997-02-11

    A method and system are disclosed for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod. 12 figs.

  19. Acrylamide/acrylic acid copolymers for cement fluid loss control

    SciTech Connect

    McKenzie, L.F.; McElfresh, P.M.

    1982-01-01

    Acrylamide/acrylic acid copolymers are considered as effective fluid loss control additives in a wide range of oil well cements. Unlike HEC based fluid loss aditives, these copolymers can be used with calcium chloride accelerator without significantly influencing fluid loss control. Another advantage of the copolymers is that the amount of fluid loss for a given concentration of polymer remains relatively constant over a wide range of temperatures. The use of acrylamide/acrylic acid copolymers has generally been restricted to wells below 60 degree C BHCT. Above that temperature chemical changes in the copolymer often lead to retardation of the cement. This paper presents data related to the use of acrylamide/acrylic acid copolymers as fluid loss control agents in oil well cementing. A comparison of these polymers with HEC based fluid loss control additives is made. In addition, data related to the cause of acrylamide/acrylic acid copolymer retarding effects is presented. 4 refs.

  20. A flexible metal–organic framework: Guest molecules controlled dynamic gas adsorption

    SciTech Connect

    Mahurin, Shannon Mark; Li, Man -Rong; Wang, Hailong; Lu, Zhengliang; Chen, Banglin; Dai, Sheng; Yue, Yanfeng; Rabone, Jeremy A.; Liu, Hongjun; Wang, Jihang; Fang, Youxing

    2015-04-13

    A flexible metal–organic framework (MOF) of [Zn3(btca)2(OH)2]·(guest)n (H2btca = 1,2,3-benzotriazole-5-carboxylic acid) that exhibits guest molecule-controlled dynamic gas adsorption is reported in which carbon dioxide molecules rather than N2, He, and Ar induce a structural transition with a corresponding appearance of additional steps in the isotherms. Physical insights into the dynamic adsorption behaviors of flexible compound 1 were detected by gas adsorption at different temperatures and different pressures and confirmed by Fourier transform infrared spectroscopy and molecular simulations. Interestingly, by taking advantage of the flexible nature inherent to the framework, this MOF material enables highly selective adsorption of CO2/N2, CO2/Ar, and CO2/He of 36.3, 32.6, and 35.9, respectively, at 298 K. Furthermore, this class of flexible MOFs has potential applications for controlled release, molecular sensing, noble gas separation, smart membranes, and nanotechnological devices.

  1. A flexible metal–organic framework: Guest molecules controlled dynamic gas adsorption

    DOE PAGES

    Mahurin, Shannon Mark; Li, Man -Rong; Wang, Hailong; ...

    2015-04-13

    A flexible metal–organic framework (MOF) of [Zn3(btca)2(OH)2]·(guest)n (H2btca = 1,2,3-benzotriazole-5-carboxylic acid) that exhibits guest molecule-controlled dynamic gas adsorption is reported in which carbon dioxide molecules rather than N2, He, and Ar induce a structural transition with a corresponding appearance of additional steps in the isotherms. Physical insights into the dynamic adsorption behaviors of flexible compound 1 were detected by gas adsorption at different temperatures and different pressures and confirmed by Fourier transform infrared spectroscopy and molecular simulations. Interestingly, by taking advantage of the flexible nature inherent to the framework, this MOF material enables highly selective adsorption of CO2/N2, CO2/Ar, andmore » CO2/He of 36.3, 32.6, and 35.9, respectively, at 298 K. Furthermore, this class of flexible MOFs has potential applications for controlled release, molecular sensing, noble gas separation, smart membranes, and nanotechnological devices.« less

  2. Advanced controls for airbreathing engines, volume 3: Allison gas turbine

    NASA Technical Reports Server (NTRS)

    Bough, R. M.

    1993-01-01

    The application of advanced control concepts to airbreathing engines may yield significant improvements in aircraft/engine performance and operability. Screening studies of advanced control concepts for airbreathing engines were conducted by three major domestic aircraft engine manufacturers to determine the potential impact of concepts on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed advanced control concepts was formulated and evaluated in a two-phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation specific aircraft/engine combinations were considered: a Military High Performance Fighter mission, a High Speed Civil Transport mission, and a Civil Tiltrotor mission. Each of the advanced control concepts considered in the study are defined and described. The concept potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts are determined. Finally, the concepts are ranked with respect to the target aircraft/engine missions. A final report describing the screening studies was prepared by each engine manufacturer. Volume 3 of these reports describes the studies performed by the Allison Gas Turbine Division.

  3. Design development and test: Two-gas atmosphere control subsystem

    NASA Technical Reports Server (NTRS)

    Jackson, J. K.

    1974-01-01

    An atmosphere control subsystem (ACS) was developed for NASA-IBJSC which is designed to measure the major atmospheric constituents in the manned cabin of the space shuttle orbiter and control the addition of oxygen and nitrogen to maintain the partial pressures of these gases within very close limits. The ACS includes a mass spectrometer sensor (MSS) which analyzes the atmosphere of a shuttle vehicle pressurized cabin, and an electronic control assembly (ECA). The MSS was built and tested to meet the requirements for flight equipment for the M-171 Metabolic Analyzer experiment for the Skylab flight program. The instrument analyzes an atmospheric gas sample and produces continuous 0-5 vdc analog signals proportional to the partial pressures of H2, O2, N2, H2O, CO2 and total hydrocarbons having a m/e ratio between 50 and 120. It accepts signals from the MSS proportional to the partial pressures of N2 and O2 and controls the supply of these gases to the closed cabin.

  4. Precise and high-speed control of partial pressures of multiple gas species in plasma process chamber using pulse-controlled gas injection

    SciTech Connect

    Morishita, Sadaharu; Goto, Tetsuya; Nagase, Masaaki; Ohmi, Tadahiro

    2009-05-15

    Multiprocesses in a single plasma process chamber with high throughput require precise, sequential, high-speed alteration of partial pressures of multiple gas species. A conventional gas-distribution system cannot realize this because the system seriously overshoots gas pressure immediately following valve operation. Furthermore, chamber volume and conductance of gas piping between the system and chamber should both be considered because they delay the stabilizing time of gas pressure. Therefore, the authors proposed a new gas-distribution system without overshoot by controlling gas flow rate based on pressure measurement, as well as a method of pulse-controlled gas injection immediately following valve operation. Time variation of measured partial pressure agrees well with a calculation based on an equivalent-circuit model that represents the chamber and gas piping between the system and chamber. Using pulse-controlled gas injection, the stabilizing time can be reduced drastically to 0.6 s for HBr added to pure Ar plasma, and 0.7 s for O{sub 2} added to Ar/HBr plasma; without the pulse control, the stabilizing times are 3 and 7 s, respectively. In the O{sub 2} addition case, rapid stabilization can be achieved during the period of line/space pattern etching of poly-Si on a thin SiO{sub 2} film. This occurs without anomalous etching of the underlying SiO{sub 2} film or the Si substrate near the sidewall, thus obtaining a wide process margin with high throughput.

  5. Bioreactor for acid mine drainage control

    DOEpatents

    Zaluski, Marek H.; Manchester, Kenneth R.

    2001-01-01

    A bioreactor for reacting an aqueous heavy metal and sulfate containing mine drainage solution with sulfate reducing bacteria to produce heavy metal sulfides and reduce the sulfuric acid content of the solution. The reactor is an elongated, horizontal trough defining an inlet section and a reaction section. An inlet manifold adjacent the inlet section distributes aqueous mine drainage solution into the inlet section for flow through the inlet section and reaction section. A sulfate reducing bacteria and bacteria nutrient composition in the inlet section provides sulfate reducing bacteria that with the sulfuric acid and heavy metals in the solution to form solid metal sulfides. The sulfate reducing bacteria and bacteria nutrient composition is retained in the cells of a honeycomb structure formed of cellular honeycomb panels mounted in the reactor inlet section. The honeycomb panels extend upwardly in the inlet section at an acute angle with respect to the horizontal. The cells defined in each panel are thereby offset with respect to the honeycomb cells in each adjacent panel in order to define a tortuous path for the flow of the aqueous solution.

  6. ENHANCED CONTROL OF MERCURY BY WET FLUE GAS DESULFURIZATION SYSTEMS

    SciTech Connect

    G. Blythe; B. Marsh; S. Miller; C. Richardson; M. Richardson

    2001-06-01

    The U.S. Department of Energy and EPRI have co-funded this project to improve the control of mercury emissions from coal-fired power plants equipped with wet flue gas desulfurization (FGD) systems. The project investigated catalytic oxidation of vapor-phase elemental mercury to a form that is more effectively captured in wet FGD systems. If successfully developed, the process could be applicable to over 90,000 MW of utility generating capacity with existing FGD systems and to future FGD installations. Field tests have been conducted to determine whether candidate catalyst materials remain active towards mercury oxidation after extended flue gas exposure. Catalyst life will have a large impact on the cost effectiveness of this potential process. A mobile catalyst test unit has been used to test the activity of four different catalyst materials for a period of up to six months at each of three utility sites. Catalyst testing was completed at the first site, which fires Texas lignite, in December 1998 and at the second test site, which fires a Powder River Basin subbituminous coal in the fall of 1999. Testing at the third site, which fires a medium- to high-sulfur bituminous coal, began in June 2000 and was completed at the end of January 2001. This Topical Reports includes results from Site 3; results from Sites 1 and 2 were reported previously. At Site 3, catalysts were tested in two forms, including powders dispersed in sand bed reactors and in a commercially available form as a coated honeycomb structure. Field testing has been supported by laboratory tests to screen catalysts for activity at specific flue gas compositions, to investigate catalyst deactivation mechanisms and methods for regenerating spent catalysts. Laboratory results related to the Site 3 field effort are also included and discussed in this Topical Report.

  7. ENHANCED CONTROL OF MERCURY BY WET FLUE GAS DESULFURIZATION SYSTEMS

    SciTech Connect

    Unknown

    2001-06-01

    The U.S. Department of Energy and EPRI co-funded this project to improve the control of mercury emissions from coal-fired power plants equipped with wet flue gas desulfurization (FGD) systems. The project has investigated catalytic oxidation of vapor-phase elemental mercury to a form that is more effectively captured in wet FGD systems. If successfully developed, the process could be applicable to over 90,000 MW of utility generating capacity with existing FGD systems, and to future FGD installations. Field tests were conducted to determine whether candidate catalyst materials remain active towards mercury oxidation after extended flue gas exposure. Catalyst life will have a large impact on the cost effectiveness of this potential process. A mobile catalyst test unit was used to test the activity of four different catalyst materials for a period of up to six months each at three utility sites. Catalyst testing was completed at the first site, which fires Texas lignite, in December 1998; at the second test site, which fires a Powder River Basin subbituminous coal, in November 1999; and at the third site, which fires a medium- to high-sulfur bituminous coal, in January 2001. Results of testing at each of the three sites were reported in previous technical notes. At Site 1, catalysts were tested only as powders dispersed in sand bed reactors. At Sites 2 and 3, catalysts were tested in two forms, including powders dispersed in sand and in commercially available forms such as extruded pellets and coated honeycomb structures. This final report summarizes and presents results from all three sites, for the various catalyst forms tested. Field testing was supported by laboratory tests to screen catalysts for activity at specific flue gas compositions, to investigate catalyst deactivation mechanisms and methods for regenerating spent catalysts. Laboratory results are also summarized and discussed in this report.

  8. 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.

  9. Factors controlling sulfur gas exchange in Sphagnum-dominated wetlands

    NASA Technical Reports Server (NTRS)

    Demello, William Zamboni; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Atmosphere-peatland exchange of reduced sulfur gases was determined seasonally in fen in NH, and in an artificially-acidified fen at the Experimental Lakes Area (ELA) in Canada. Dimethyl sulfide (DMS) dominated gas fluxes at rates as high as 400 nmol/m(sup -2)hr(sup -1). DMS fluxes measured using enclosures were much higher than those calculated using a stagnant-film model, suggesting that Sphagnum regulated efflux. Temperature controlled diel and seasonal variability in DMS emissions. Use of differing enclosure techniques indicated that vegetated peatlands consume atmospheric carbonyl sulfide. Sulfate amendments caused DMS and methane thiol concentrations in near-surface pore waters to increase rapidly, but fluxes of these gases to the atmosphere were not affected. However, emission data from sites experiencing large differences in rates of sulfate deposition from the atmosphere suggested that chronic elevated sulfate inputs enhance DMS emissions from northern wetlands.

  10. Design, Control and in Situ Visualization of Gas Nitriding Processes

    PubMed Central

    Ratajski, Jerzy; Olik, Roman; Suszko, Tomasz; Dobrodziej, Jerzy; Michalski, Jerzy

    2010-01-01

    The article presents a complex system of design, in situ visualization and control of the commonly used surface treatment process: the gas nitriding process. In the computer design conception, analytical mathematical models and artificial intelligence methods were used. As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers. For in situ visualization of the growth of the nitrided layer, computer procedures were developed which make use of the results of the correlations of direct and differential voltage and time runs of the process result sensor (magnetic sensor), with the proper layer growth stage. Computer procedures make it possible to combine, in the duration of the process, the registered voltage and time runs with the models of the process. PMID:22315536

  11. 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.

  12. Revision of the gas-phase acidity scale below 300 kcal mol(-1).

    PubMed

    Leito, Ivo; Raamat, Elin; Kütt, Agnes; Saame, Jaan; Kipper, Karin; Koppel, Ilmar A; Koppel, Ivar; Zhang, Min; Mishima, Masaaki; Yagupolskii, Lev M; Garlyauskayte, Romute Yu; Filatov, Andrey A

    2009-07-23

    The gas-phase acidity (GA) scale from (CF(3)CO)(2)NH to (C(2)F(5)SO(2))(2)NH--about a 24 kcal mol(-1) range of gas-phase acidities--was reexamined using the Fourier transform ion cyclotron resonance equilibrium measurement approach. Some additions and modifications to the standard methodology of GA measurements were introduced (estimation of partial pressures from mass spectra of the compounds, instead of the pressure gauge readings and use of long reaction times) to achieve higher reliability. Gas-phase acidities of 18 compounds were determined for the first time. The results reveal a contraction of the previously published values in this part of the scale. In particular, the GA values of (CF(3)SO(2))(2)NH and (C(2)F(5)SO(2))(2)NH (important components of lithium ion battery electrolytes and ionic liquids) were revised toward stronger acidities from 291.8 kcal mol(-1) to 286.5 kcal mol(-1) and from 289.4 kcal mol(-1) to 283.7 kcal mol(-1) (i.e., by 5.3 and 5.7 kcal mol(-1)), respectively. Experimental and computational evidence is presented in support of the current results.

  13. 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.

  14. Acetic acid and weed control in onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems, especially for organically produced sweet onion (Allium cepa L.). Although corn gluten meal shows great promise as an organic preemergent herbicide for onions, research has shown the need for supplemental, postemergen...

  15. Air-sea transfer of gas phase controlled compounds

    NASA Astrophysics Data System (ADS)

    Yang, M.; Bell, T. G.; Blomquist, B. W.; Fairall, C. W.; Brooks, I. M.; Nightingale, P. D.

    2016-05-01

    Gases in the atmosphere/ocean have solubility that spans several orders of magnitude. Resistance in the molecular sublayer on the waterside limits the air-sea exchange of sparingly soluble gases such as SF6 and CO2. In contrast, both aerodynamic and molecular diffusive resistances on the airside limit the exchange of highly soluble gases (as well as heat). Here we present direct measurements of air-sea methanol and acetone transfer from two open cruises: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The transfer of the highly soluble methanol is essentially completely airside controlled, while the less soluble acetone is subject to both airside and waterside resistances. Both compounds were measured concurrently using a proton-transfer-reaction mass spectrometer, with their fluxes quantified by the eddy covariance method. Up to a wind speed of 15 m s-1, observed air-sea transfer velocities of these two gases are largely consistent with the expected near linear wind speed dependence. Measured acetone transfer velocity is ∼30% lower than that of methanol, which is primarily due to the lower solubility of acetone. From this difference we estimate the “zero bubble” waterside transfer velocity, which agrees fairly well with interfacial gas transfer velocities predicted by the COARE model. At wind speeds above 15 m s-1, the transfer velocities of both compounds are lower than expected in the mean. Air-sea transfer of sensible heat (also airside controlled) also appears to be reduced at wind speeds over 20 m s-1. During these conditions, large waves and abundant whitecaps generate large amounts of sea spray, which is predicted to alter heat transfer and could also affect the air-sea exchange of soluble trace gases. We make an order of magnitude estimate for the impacts of sea spray on air-sea methanol transfer.

  16. 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.

  17. Pyrolysis-gas chromatography-mass spectrometry of a series of bile acid sequestrants.

    PubMed

    Haskins, N J; Eckers, C; Mitchell, R

    1992-09-01

    Pyrolysis of a series of polymers based on polystyrene and used as bile acid sequestrants produced characteristic mixtures of compounds which were analysed by gas chromatography-mass spectrometry. The nature of the substituent groups was clearly apparent while the polymer backbone gave rise to representative styrenes. The reproducibility of the results was examined by experimenting with the temperature of pyrolysis. It was found that at low temperatures very little fragmentation of the polystyrene backbone occurred but the substituents were still released in high yield. The orientation of the various substituted styrenes generated by pyrolysis was confirmed by the use of gas chromatography with infrared and mass spectrometric detection.

  18. Designing systems for landfill gas migration control in Minnesota

    SciTech Connect

    Cannon, J.

    1996-11-01

    Camp, Dresser & McKee (CDM) has designed or is in the process of designing several landfill gas migration control systems in Minnesota. The systems are for both active and closed municipal solid waste landfills. The sites have a variety of covers, including geomembranes, clay caps, and non-engineered soil covers. The control system types include small perimeter systems, full-site systems and phased systems for active sites. Figure 1 shows the locations of the systems CDM is working on in Minnesota. This paper focuses on four sites: Oak Grove Landfill, Hopkins Landfill, Washington County Landfill, and Elk River Landfill. Table 1 provides an outline of the individual site characteristics. The first three sites are closed landfills. The Oak Grove Landfill system was designed and constructed for a group of industries responsible for closure and remedial action. The Hopkins and Washington County landfills are under the control of the Minnesota Pollution Control Agency (MPCA). The MPCA enacted a remedial action program at closed landfills, taking over responsibility for long-term liability under the terms of legally binding agreements negotiated with the site owners. The Elk River Landfill is an active, privately-owned facility. The migration problems and solutions developed for these four landfills are generally descriptive of all the landfills CDM is working on in Minnesota. All landfills have unique characteristics requiring site-specific solutions. CDM, after designing a number of migration control systems in Minnesota, is able to provide a generalized description of design options for specific types of sites. This paper discussions design options used to address different cover types, aesthetic needs, and waste depths, and includes a discussion of design needs for cold climates. A brief case history of the Oak Grove Landfill is included.

  19. Gas chromatography determination of fatty acids in the human erythrocyte membranes - A review.

    PubMed

    Bystrická, Zuzana; Ďuračková, Zdeňka

    2016-12-01

    Blood fatty acid measurements can reflect exogenously consumed fatty acids allowing to resolve some metabolic disorders (e.g. diabetes, anorexia) or mental disorders (e.g. depression, anxiety, schizophrenia). For this purpose, fatty acids can be determined in the whole blood or various blood fractions such as the plasma, serum or erythrocytes. Measurement of fatty acids in the whole blood by dried blood spot technique is becoming increasingly popular and is often used mainly for the screening of newborns due to the use of the small sample volume. The most popular is determination of fatty acids in plasma or serum samples. While the profile of plasma fatty acids fluctuates based on daily dietary intake, the red blood cell membrane composition of fatty acids reflects the 2-3 month dietary intake. Such results can be more reflective in contrast to the plasma/serum and therefore the present review will summarize available information on gas chromatography determination of fatty acids in human red blood cell membranes. Selection of extraction and derivatization reagents as well as presentation of chromatographic conditions will be discussed here.

  20. Improved gas chromatography-flame ionization detector analytical method for the analysis of epoxy fatty acids.

    PubMed

    Mubiru, Edward; Shrestha, Kshitij; Papastergiadis, Antonios; De Meulenaer, Bruno

    2013-11-29

    In this study an improved method for analysis of epoxy fatty acids is reported. Data obtained from analysis of polar fatty acids has previously been presented, but due to the high number of compounds that co-elute in the polar fraction, the resultant chromatograms are complex which may lead to compromising the accuracy of the data. A three steps separation of fatty acid methyl esters (FAMEs) by solid-phase extraction (SPE) on a silica gel column to remove hydroxy fatty acid interferences was proposed. This approach is opposed to a two step separation procedure that has been often used to prevent analytical interferences caused by non-altered fatty acids. A gas chromatograph with a flame ionization detector (GC-FID) equipped with a polar CP-Sil 88™ column was used. Quantification was based on the use of methyl nonadecanoate (C19:0), as an internal standard. Individual mono epoxy fatty acids were well separated without co-eluting compounds. The optimized method was finally applied to screen epoxy fatty acids in 37 fresh oil samples. Results obtained for the total epoxy fatty acids were in the range 0.03-2mgg(-1) of oil with repeatability coefficient of variation (CV) ranging from 2.8 to 9.9% for duplicate analysis showing that the results obtained are repeatable.

  1. [Determination of 13C enrichment in soil amino acid enantiomers by gas chromatogram/mass spectrometry].

    PubMed

    He, Hong-Bo; Zhang, Wei; Ding, Xue-Li; Bai, Zhen; Liu, Ning; Zhang, Xu-Dong

    2008-06-01

    The transformation and renewal of amino acid enantiomers is of significance in indicating the turnover mechanism of soil organic matter. In this paper, a method of gas chromatogram/mass spectrometry combined with U-13 C-glucose incubation was developed to determine the 13C enrichment in soil amino acid enantiomers, which could effectively differentiate the original and the newly synthesized amino acids in soil matrix. The added U-13 C-glucose was utilized rapidly to structure the amino acid carbon skeleton, and the change of relative abundance of isotope ions could be determined by mass spectrometry. The direct incorporation of U-13 C glucose was estimated by the intensity increase of m/z (F + n) to F (F was parent fragment, and n was the carbon number in the fragment), while the total isotope incorporation from the added 13C could be calculated according to the abundance ratio increment summation from m/z (Fa + 1) through (Fa + T) (Fa was the fragment containing all original skeleton carbons, and T was the carbon number in the amino acid molecule). The 13C enrichment in the target compound was expressed as atom percentage excess (APE), and that of D-amino acid needed to be corrected by the coefficient of hydrolysis-induced racemization. The 13C enrichment reflected the carbon turnover velocity of individual amino acid enantiomers, and was powerful to investigate the dynamics of soil amino acids.

  2. Gas chromatography-mass spectrometry profiles of urinary organic acids in healthy captive cheetahs (Acinonyx jubatus).

    PubMed

    Tordiffe, Adrian Stephen Wolferstan; van Reenen, Mari; Reyers, Fred; Mienie, Lodewyk Jacobus

    2017-04-01

    In captivity, cheetahs (Acinonyx jubatus) frequently suffer from several unusual chronic diseases that rarely occur in their free-ranging counterparts. In order to develop a better understanding of their metabolism and health we documented the urine organic acids of 41 apparently healthy captive cheetahs, in an untargeted metabolomic study, using gas chromatography-mass spectrometry. A total of 339 organic acids were detected and annotated. Phenolic compounds, thought to be produced by the anaerobic fermentation of aromatic amino acids in the distal colon, as well as their corresponding glycine conjugates, were present in high concentrations. The most abundant organic acids in the cheetahs' urine were an as yet unidentified compound and a novel cadaverine metabolite, tentatively identified as N(1),N(5)-dimethylpentane-1,5-diamine. Pantothenic acid and citramalic acid concentrations correlated negatively with age, while glutaric acid concentrations correlated positively with age, suggesting possible dysregulation of coenzyme A metabolism in older cheetahs. This study provides a baseline of urine organic acid reference values in captive cheetahs and suggests important avenues for future research in this species.

  3. Controlling Air Pollution from the Oil and Natural Gas Industry

    EPA Pesticide Factsheets

    EPA regulations for the oil and natural gas industry help combat climate change and reduce air pollution that harms public health. EPA’s regulations apply to oil production, and the production, process, transmission and storage of natural gas.

  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. Application of Fuzzy-Logic Controller and Neural Networks Controller in Gas Turbine Speed Control and Overheating Control and Surge Control on Transient Performance

    NASA Astrophysics Data System (ADS)

    Torghabeh, A. A.; Tousi, A. M.

    2007-08-01

    This paper presents Fuzzy Logic and Neural Networks approach to Gas Turbine Fuel schedules. Modeling of non-linear system using feed forward artificial Neural Networks using data generated by a simulated gas turbine program is introduced. Two artificial Neural Networks are used , depicting the non-linear relationship between gas generator speed and fuel flow, and turbine inlet temperature and fuel flow respectively . Off-line fast simulations are used for engine controller design for turbojet engine based on repeated simulation. The Mamdani and Sugeno models are used to expression the Fuzzy system . The linguistic Fuzzy rules and membership functions are presents and a Fuzzy controller will be proposed to provide an Open-Loop control for the gas turbine engine during acceleration and deceleration . MATLAB Simulink was used to apply the Fuzzy Logic and Neural Networks analysis. Both systems were able to approximate functions characterizing the acceleration and deceleration schedules . Surge and Flame-out avoidance during acceleration and deceleration phases are then checked . Turbine Inlet Temperature also checked and controls by Neural Networks controller. This Fuzzy Logic and Neural Network Controllers output results are validated and evaluated by GSP software . The validation results are used to evaluate the generalization ability of these artificial Neural Networks and Fuzzy Logic controllers.

  6. Semicontinuous measurements of gas-particle partitioning of organic acids in a ponderosa pine forest using a MOVI-HRToF-CIMS

    NASA Astrophysics Data System (ADS)

    Yatavelli, R. L. N.; Stark, H.; Thompson, S. L.; Kimmel, J. R.; Cubison, M. J.; Day, D. A.; Campuzano-Jost, P.; Palm, B. B.; Hodzic, A.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2014-02-01

    Hundreds of gas- and particle-phase organic acids were measured in a rural ponderosa pine forest in Colorado, USA, during BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study). A recently developed micro-orifice volatilization impactor high-resolution time-of-flight chemical ionization mass spectrometer (MOVI-HRToF-CIMS) using acetate (CH3C(O)O-) as the reagent ion was used to selectively ionize and detect acids semicontinuously from 20 to 30 August 2011, with a measurement time resolution of ~1.5 h. At this site 98% of the organic acid mass is estimated to be in the gas phase, with only ~2% in the particle phase. We investigated gas-particle partitioning, quantified as the fraction in the particle phase (Fp), of C1-C18 alkanoic acids, six known terpenoic acids, and bulk organic acids vs. carbon number. Data were compared to the absorptive partitioning model and suggest that bulk organic acids at this site follow absorptive partitioning to the organic aerosol mass. The rapid response (<1-2 h) of partitioning to temperature changes for bulk acids suggests that kinetic limitations to equilibrium are minor, which is in contrast to conclusions of some recent laboratory and field studies, possibly due to lack of very low ambient relative humidities at this site. Time trends for partitioning of individual and groups of acids were mostly captured by the model, with varying degrees of absolute agreement. Species with predicted substantial fractions in both the gas and particle phases show better absolute agreement, while species with very low predicted fractions in one phase often show poor agreement, potentially due to thermal decomposition, inlet adsorption, or other issues. Partitioning to the aqueous phase is predicted to be smaller than to the organic phase for alkanoic and bulk acids, and has different trends with time and carbon number than observed experimentally. This is due

  7. Gas chromatography-mass spectrometry analysis of effects of dietary fish oil on total fatty acid composition in mouse skin

    PubMed Central

    Wang, Peiru; Sun, Min; Ren, Jianwei; Djuric, Zora; Fisher, Gary J.; Wang, Xiuli; Li, Yong

    2017-01-01

    Altering the fatty acid (FA) composition in the skin by dietary fish oil could provide therapeutic benefits. Although it has been shown that fish oil supplementation enhances EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) abundance in the skin, comprehensive skin FA profiling is needed. We established a gas chromatography-mass spectrometry method, which allows precise quantification of FA profile using small (<24 mm2 for mice and <12 mm2 for humans) skin specimens that can be readily obtained from live mice and humans. We determined mouse skin FA composition after 2, 4 and 8 weeks of consuming a control diet or a diet supplemented with fish oil. Fish oil markedly enhanced EPA and DHA in mouse skin within 2 weeks, and this increase plateaued after 4 weeks. The FA composition in mouse skin was different from that of serum, indicating that skin has homeostatic control of FA metabolism. Mice fed the control diet designed to simulate Western human diet displayed similar skin FA composition as that of humans. The present study presents a validated method for FA quantification that is needed to investigate the mechanisms of actions of dietary treatments in both mouse and human skin. PMID:28195161

  8. Development of monitoring and control technology based on trace gas monitoring. Final report

    SciTech Connect

    Liebowitz, B.

    1997-07-01

    Trace gases are generated by many biological reactions. During anaerobic decomposition, trace levels of hydrogen (H{sub 2}) and carbon monoxide (CO) gases are produced. It was shown previously that these trace gases are intrinsically related to the biochemical reactions occurring and, therefore, offer promise for on-line process monitoring and control. This work was designed to test how effectively hydrogen and CO could be to monitor high-rate anaerobic systems that has significant mass transfer and complex hydraulics. An experimental program was designed to examine the behavior of an upflow anaerobic sludge blanket (UASB) reactor system under steady state and in response to organic loading perturbations. The responses of trace gases CO and H{sub 2} were tracked using an on-line, real-time gas-monitoring system linked to a computer-controlled data acquisition package. Data on conventional process parameters such as pH, chemical oxygen demand (COD), volatile fatty acids (VFAs) were concurrently collected. Monitoring of conventional process indicators (i.e., pH, VFA, gas production) and trace gas (H{sub 2} and CO) indicators was conducted using a matrix of nine different steady-state OLRs (4-23 kg COD/m{sup 3} -d) and system HRTs (0.5 to 2.5 days) was performed to determine any correlation among the indicators. Of OLR, HRT, and influent COD, only OLR had any significant influence on the process indicators examined. All parameters except methane increased with increases in OLR; methane decreased with increased OLR. The OLR and gas production rate (GP) were observed to be linearly correlated.

  9. 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.

  10. [Determination of 2-methyl-3-nitrobenzoic acid through pretreatment with diazomethane by gas chromatography].

    PubMed

    Xue, Ke-She; Nan, Zhi-Xiang

    2002-09-01

    A method for the quantitative determination of 2-methyl-3-nitrobenzoic acid by gas chromatography is described. 2-Methyl-3-nitrobenzoic acid was esterified by pretreatment with diazomethane prior to analysis. A CP-Sil-43CB capillary column(25 m x 0.32 mm i.d. x 0.2 microm), a flame ionization detector and the area normalization method were used. The average recovery was 99.81%. The RSD was 0.08% and the detection limit was 3 x 10(-11) g. The results showed that the method is practical and reliable. It was realized that the higher purity and higher boiler matter was analyzed by gas chromatography. The method can be used to monitor the purity of this type of materials. analysis of research and production. It can be used in the development of new products and in the process.

  11. Hydration energies of deprotonated amino acids from gas phase equilibria measurements.

    PubMed

    Wincel, Henryk

    2008-08-01

    Singly hydrated clusters of deprotonated amino acids were studied using an electrospray high-pressure mass spectrometer equipped with a pulsed ion-beam reaction chamber. Thermochemical data, DeltaH(o), DeltaS(o), and DeltaG(o), for the hydration reaction [AA - H](-) + H(2)O = [AA - H](-).(H(2)O) were obtained from gas-phase equilibria determinations for AA = Gly, Ala, Val, Pro, Phe, Lys, Met, Trp, Gln, Arg, and Asp. The hydration free-energy changes are found to depend significantly on the side-chain substituents. The water binding energy in [AA - H](-).(H(2)O) increases with the gas-phase acidity of AA. The anionic hydrogen bond strengths in [AA - H](-).(H(2)O) are compared with those of the cationic bonds in the corresponding AAH(+).(H(2)O) systems.

  12. Recent Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2004-01-01

    A dual-membrane gas trap is currently used to remove gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the gas bubbles. The inner hydrophobic fiber allows the trapped gas bubbles to pass through and vent to the ambient atmosphere in the cabin. The gas removal performance and operational lifetime of the gas trap have been affected by contamination in the ITCS coolant. However, the gas trap has performed flawlessly with regard to its purpose of preventing gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump. This paper discusses on-orbit events over the course of the last year related to the performance and functioning of the gas trap.

  13. 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.

    2014-09-01

    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 in June-July of 2010 during CalNex and a site in an oil and gas producing region in January-February of 2013 during UBWOS 2013 will be discussed. Although the VOC compositions differed dramatically at the two sites, measured formic acid concentrations were comparable: 2.3 ± 1.3 ppb 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 (> 8%). 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). Inclusion of recent findings on additional precursors and formation pathways of formic acid in the box model increases modeled formic acid concentrations for UBWOS 2013 and CalNex by a factor of 6.4 and 4.5, 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 21 and 47% 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 -7 and 0-6% in UBWOS 2013 and CalNex, respectively. We observe that air-snow exchange processes and morning fog events may also contribute to ambient formic acid concentrations during UBWOS 2013 (∼20% in total). In total, 50-57% in UBWOS 2013 and 48-53% in CalNex of secondary formation of formic acid remains unexplained. More work on formic acid formation pathways is needed to reduce the uncertainties in the sources and budget of formic

  14. Insights into diastereoisomeric characterization of tetrahydropyridazine amino acid derivatives: crystal structures and gas phase ion chemistry.

    PubMed

    Giorgi, Gianluca; Favi, Gianfranco; Attanasi, Orazio A

    2013-08-14

    Structural, conformational properties, and gas phase reactivity of two representative diastereoisomeric members of a series of α,α-tetrahydropyridazine amino acid derivatives have been investigated by using X-ray crystallography, tandem mass spectrometry and theoretical calculations. Both diastereoisomers show an unusual screw-boat conformation of the tetrahydropyridazine ring. While protonated molecules mainly decompose in the gas phase by loss of acetamide, the main reactivity of the [M + Na](+) species consists of loss of PhNCO followed by acetamide and it is strictly dependent upon the stereochemistry of the parent compound. The most stable energy minimized structures obtained by theoretical calculations are in full agreement with the experimental data and allowed us to rationalize the gas phase reaction pathways.

  15. 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.

  16. 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

  17. Commercialization Development of Oxygen Fired CFB for Greenhouse Gas Control

    SciTech Connect

    Nsakala ya Nsakala; Gregory N. Liljedahl; David G. Turek

    2007-03-31

    {sub 2} fired MTF pilot testing and a subsequent retrofit design study of oxygen firing and CO{sub 2} capture on an existing air-fired CFB plant. ALSTOM received a contract award from the DOE to conduct a project entitled 'Commercialization Development of Oxygen Fired CFB for Greenhouse Gas Control', under Cooperative Agreement DE-FC26-04NT42205 that is the subject of this topical report.

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

    PubMed

    Musshoff, F; Daldrup, T

    1997-08-04

    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.

  19. 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.

  20. A novel decomposition technique of friable asbestos by CHClF2-decomposed acidic gas.

    PubMed

    Yanagisawa, Kazumichi; Kozawa, Takahiro; Onda, Ayumu; Kanazawa, Masazumi; Shinohara, Junichi; Takanami, Tetsuro; Shiraishi, Masatsugu

    2009-04-30

    Asbestos was widely used in numerous materials and building products due to their desirable properties. It is, however, well known that asbestos inhalation causes health damage and its inexpensive decomposition technique is necessary to be developed for pollution prevention. We report here an innovative decomposition technique of friable asbestos by acidic gas (HF and HCl) generated from the decomposition of CHClF(2) by the reaction with superheated steam at 800 degrees C. Chrysotile-asbestos fibers were completely decomposed to sellaite and magnesium silicofluoride hexahydrate by the reaction with CHClF(2)-decomposed acidic gas at 150 degrees C for 30 min. At high temperatures beyond 400 degrees C, sellaite and hematite were detected in the decomposed product. In addition, crocidolite containing wastes and amosite containing wastes were decomposed at 500 degrees C and 600 degrees C for 30 min, respectively, by CHClF(2)-decomposed acidic gas. The observation of the reaction products by phase-contrast microscopy (PCM) and scanning electron microscopy (SEM) confirmed that the resulting products did not contain any asbestos.

  1. A microcomputer-controlled gas phase microreactor system

    SciTech Connect

    Morris, R.M.

    1983-08-01

    Although automated reactors are effective tools for studying a single type of reaction or optimizing catalyst performance, they may not be well suited for exploratory research. These reactors generally have several shortcomings. First, they may have limited versatility since they are usually designed with a single application in mind. Second, computer systems used for process control and data acquisition are often expensive and complex, so that once they are set up for a given application, it is quite difficult to adapt them for another. Because of these restrictions, experimental reactors are often operated manually, requiring a full-time operator to monitor operations and acquire data. This is a greater problem in laboratories where projects are often short-term, and the costs of setting up an automated reactor may outweigh the benefits of automation. For an automated reactor to be cost-effective in such an environment, both reactor hardware and control software must be versatile enough that they can be easily modified and adapted for different experiments. An automated gas-flow microreactor has been designed and constructed which is both inexpensive and flexible. The reactor is capable of performing three different types of experiments, 1) continuous reagent feed with analysis of the product stream, 2) pulsed-flow experiments, and 3) temperature-programmed desorption (TPD) and reaction (TPR). Conversion of the reactor from one configuration to another requires less than one hour. Process control and data acquisition are performed using an Apple II Plus microcomputer (Apple Computer Corp., Cupertino, Calif.) and an ISAAC interface device (Cyborg Corp., Newton, Mass.).

  2. 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

  3. Controlled fed-batch fermentations of dilute-acid hydrolysate in pilot development unit scale.

    PubMed

    Rudolf, Andreas; Galbe, Mats; Lidén, Gunnar

    2004-01-01

    Inhibitors formed during wood hydrolysis constitute a major problem in fermenting dilute-acid hydrolysates. By applying a fed-batch technique, the levels of inhibitory compounds may be held low, enabling high ethanol productivity. In this study, a previously developed fed-batch strategy was modified and implemented for use in pilot development unit (PDU) scale. The rate of total gas formation, measured with a mass flow meter, was used as input variable in the control algorithm. The feed rate in the PDU-scale experiments could be properly controlled based on the gas evolution from the reactor. In fed-batch experiments utilizing TMB 3000, an inhibitor-tolerant strain of Saccharomyces cerevisiae, close to 100% of the hexoses in the hydrolysate was converted.

  4. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid

    PubMed Central

    Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae

    2016-01-01

    Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease. PMID:27258452

  5. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid.

    PubMed

    Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae; Kim, Jin-Cheol

    2016-01-01

    Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.

  6. Validation of acid washes as critical control points in hazard analysis and critical control point systems.

    PubMed

    Dormedy, E S; Brashears, M M; Cutter, C N; Burson, D E

    2000-12-01

    A 2% lactic acid wash used in a large meat-processing facility was validated as an effective critical control point (CCP) in a hazard analysis and critical control point (HACCP) plan. We examined the microbial profiles of beef carcasses before the acid wash, beef carcasses immediately after the acid wash, beef carcasses 24 h after the acid wash, beef subprimal cuts from the acid-washed carcasses, and on ground beef made from acid-washed carcasses. Total mesophilic, psychrotrophic, coliforms, generic Escherichia coli, lactic acid bacteria, pseudomonads, and acid-tolerant microorganisms were enumerated on all samples. The presence of Salmonella spp. was also determined. Acid washing significantly reduced all counts except for pseudomonads that were present at very low numbers before acid washing. All other counts continued to stay significantly lower (P < 0.05) than those on pre-acid-washed carcasses throughout all processing steps. Total bacteria, coliforms, and generic E. coli enumerated on ground beef samples were more than 1 log cycle lower than those reported in the U.S. Department of Agriculture Baseline data. This study suggests that acid washes may be effective CCPs in HACCP plans and can significantly reduce the total number of microorganisms present on the carcass and during further processing.

  7. The regional costs and benefits of acid rain control

    SciTech Connect

    Berkman, M.P.

    1991-01-01

    Congress recently enacted acid rain control legislation as part of the 1990 Clean Air Act Amendments following a decade-long debate among disparate regional interests. Although Congress succeeded in drafting a law acceptable to all regions, the regional costs and benefits of the legislation remain uncertain. The research presented here attempts to estimate the regional costs and benefits and the economic impacts of acid rain controls. These estimates are made using a modeling system composed of econometric, linear programming and input-output models. The econometric and linear programming components describe markets for electricity and coal. The outputs of these components including capital investment, electricity demand, and coal production are taken as exogenous inputs by a multiregional input-output model. The input-output model produces estimates of changes in final demand, gross output, and employment. The utility linear programming model also predicts sulfur dioxide emissions (an acid-rain precursor). According to model simulations, the costs of acid rain control exceed the benefits for many regions including several regions customarily thought to be the major beneficiaries of acid rain control such as New England.

  8. [Analysis of cis-9, trans-11-conjugated linoleic acid in milk fat by capillary gas chromatography].

    PubMed

    Wang, Xiaojing; Shen, Xiangzhen; Han, Hangru; Zhao, Ruqian; Chen, Jie

    2006-11-01

    Conjugated linoleic acid (CLA) is a term representing a mixture of positional and geometric isomers of octadecadienoic acid with a conjugated double bond system. Conjugated linoleic acid has attracted a great deal of interest among nutritionists because it is a natural fat component that appears to have a number of health improvement properties. The cis-9, trans-11-CLA is the major CLA isomer found in dairy products accounting for 75% to 90% of the total CLA in milk fat. A capillary gas chromatographic method equipped with a flame ionization detector for the analysis of the cis-9, trans-11-CLA in milk fat was developed. The cis-9, trans-11-CLA was extracted with hexane-isopropanol, methylated with methanol-sodium methylate and cis-9, trans-11-CLA was separated and quantified using gas chromatography. Retention time of the peaks was used for qualitative analysis, while external standard method was used for quantitative analysis. The recovery of the cis-9, trans-11-CLA was 100.26%. The relative standard deviation was 1.9% (n = 6). This method presented is advantageous for high precision, high sensitivity analysis with smaller sample size and simpler pretreatment. It would be of significance for analyzing the contents of other fatty acids in the milk and milk products.

  9. 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.

  10. Gas chromatography - optical fiber detector for assessment of fatty acids in urban soils.

    PubMed

    Silva, Lurdes; Cachada, Anabela; Pereira, Ruth; Freitas, Ana Cristina; Rocha-Santos, Teresa A P; Panteleitchouk, Teresa S L; Pereira, Maria E; Duarte, Armando Costa

    2011-07-15

    Fatty acids have been used as biomarkers of the microbial community composition of soils and they are usually separated and quantified by gas-chromatography coupled to a flame ionization detector (GC-FID). The aim of this study was to develop, validate and apply a methodology based on gas chromatography coupled to optical fiber detection (GC-OF) for screening five fatty acids used as indicators of fungal and bacterial communities in urban soils. The performance of the GC-OF methodology (optical fiber detector at 1,550 nm) was evaluated by comparison with the GC-FID methodology and it was found that they were comparable in terms of linear range, detection limit and analytical errors. Besides these similar analytical characteristics, the GC-OF is much cheaper than the GC-FID methodology. Different concentrations were determined for each fatty acid indicator which in turn varied significantly between the soil samples analyzed from Lisbon ornamental gardens. Additionally, the GC-OF showed a great potential as alternative for determination of eleven or more fatty acids in urban soils.

  11. 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.

  12. SO2 gas adsorption by modified kaolin clays: influence of previous heating and time acid treatments.

    PubMed

    Volzone, Cristina; Ortiga, Jose

    2011-10-01

    Modified kaolin clays were used as adsorbents for SO(2) gas adsorptions. The clays were heated up to 900 °C previous to acid treatments with 0.5 N sulfuric acid solutions at boiling temperature during different times up to 1440 min. Equilibrium adsorption at 25 °C and 0.1 MPa was carried out by using a volumetric apparatus. The samples were characterized by chemical analysis, X-ray diffraction and infrared analysis. The heating of the clays followed by acid treatment improved the adsorption capacity of the kaolin clays. The presence of amorphous silica and hydroxyl in the final products improved SO(2) adsorption capacity. Better properties for SO(2) adsorption were found in kaolin rich in not well ordered kaolinite clay mineral.

  13. Ferroelectric control of two dimensional electron gas in oxide heterointerface

    NASA Astrophysics Data System (ADS)

    Thanh, Tra Vu; Chen, Jhih-Wei; Yeh, Chao-Hui; Chen, Yi-Chun; Wu, Chung-Lin; Lin, Jiunn Yuan; Chu, Ying-Hao

    2012-02-01

    Oxide heterointerfaces are emerging as one of the most exciting materials systems in condensed-matter science. One remarkable example is the LaAlO3 /SrTiO3 (LAO/STO) interface, a model system in which a highly mobile electron gas forms between two band insulators. Our study to manipulate the conductivity at this interface by using ferroeletricity of Pb(Zr,Ti)O3. Our transport data strongly suggests that down polarization direction depletes the conducting interface of LAO/STO. After switching the polarization direction (up), it becomes accumulation. In addition, our experiments show there is obvious the band structure changed by cross-sectional scanning tunneling microscopy and combining with X-ray photoelectron spectroscopy (XPS) measurements. The transport properties are measured to build up the connection between macroscopic properties and local electronic structures that have been applied to study this structure. Controlling the conductivity of this oxide interface suggests that this technique may not only extend more generally to other oxide systems but also open much potential to ferroelectric field effect transistors.

  14. Method for controlling exhaust gas heat recovery systems in vehicles

    DOEpatents

    Spohn, Brian L.; Claypole, George M.; Starr, Richard D

    2013-06-11

    A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

  15. Interaction of gas phase oxalic acid with ammonia and its atmospheric implications.

    PubMed

    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.

  16. 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.

  17. 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.

  18. Determination of thermally induced trans-fatty acids in soybean oil by attenuated total reflectance fourier transform infrared spectroscopy and gas chromatography analysis.

    PubMed

    Li, An; Ha, Yiming; Wang, Feng; Li, Weiming; Li, Qingpeng

    2012-10-24

    The intake of edible oil containing trans-fatty acids has deleterious effects mainly on the cardiovascular system. Thermal processes such as refining and frying cause the formation of trans-fatty acids in edible oil. This study was conducted to investigate the possible formation of trans-fatty acids because of the heat treatment of soybean oil. The types of trans-fatty acids in heated soybean oil are determined by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry methods. The effects of the heating temperature on the trans-fatty acids in soybean oil were evaluated using gas chromatography flame ionization detection analysis. Results show that heat treatment at 240 °C causes the formation of trans-fatty acids in soybean oil and the amount of trans-fatty acids increases with heating time. The only peak observed at 966 cm(-1) of the samples indicates the formation of nonconjugated trans isomers in the heated soybean oil. The major types of trans-fatty acids formed were trans-polyunsaturated fatty acids. Significant increases (P < 0.05) in the amounts of two trans-linoleic acids (C18:2-9c,12t and C18:2-9t,12c) and four trans-linolenic acids (C18:3-9c,12c,15t, C18:3-9t,12c,15c, and C18:3-9t,12t,15c/C18:3-9t,12c,15t) in soybean oil heated to temperatures exceeding 200 °C were compared with those of the control sample. The heating temperature and duration should be considered to reduce the formation of trans-fatty acids during thermal treatment.

  19. Greenhouse gas emission from covered windrow composting with controlled ventilation.

    PubMed

    Ermolaev, Evgheni; Pell, Mikael; Smårs, Sven; Sundberg, Cecilia; Jönsson, Håkan

    2012-02-01

    Data on greenhouse gas (GHG) emissions from full-scale composting of municipal solid waste, investigating the effects of process temperature and aeration combinations, is scarce. Oxygen availability affects the composition of gases emitted during composting. In the present study, two experiments with three covered windrows were set up, treating a mixture of source separated biodegradable municipal solid waste (MSW) fractions from Uppsala, Sweden, and structural amendment (woodchips, garden waste and re-used compost) in the volume proportion 1:2. The effects of different aeration and temperature settings on the emission of methane (CH(4)), nitrous oxide (N(2)O) and carbon dioxide (CO(2)) during windrow composting with forced aeration following three different control schemes were studied. For one windrow, the controller was set to keep the temperature below 40 °C until the pH increased, another windrow had minimal aeration at the beginning of the process and the third one had constant aeration. In the first experiment, CH(4) concentrations (CH(4):CO(2) ratio) increased, from around 0.1% initially to between 1 and 2% in all windrows. In the second experiment, the initial concentrations of CH(4) displayed similar patterns of increase between windrows until day 12, when concentration peaked at 3 and 6%, respectively, in two of the windrows. In general, the N(2)O fluxes remained low (0.46 ± 0.02 ppm) in the experiments and were two to three times the ambient concentrations. In conclusion, the emissions of CH(4) and N(2)O were low regardless of the amount of ventilation. The data indicates a need to perform longer experiments in order to observe further emission dynamics.

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

    PubMed

    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

    2016-03-27

    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

    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.

  2. 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

  3. Formation of Small Gas Phase Carbonyls from Heterogeneous Oxidation of Polyunsaturated Fatty Acids (PUFA)

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Zhao, R.; Lee, A.; Gao, S.; Abbatt, J.

    2011-12-01

    Fatty acids (FAs) are emitted into the atmosphere from gas and diesel powered vehicles, cooking, plants, and marine biota. Field measurements have suggested that FAs, including polyunsaturated fatty acids (PUFA), could make up an important contribution to the organic fraction of atmospheric aerosols. Due to the existence of carbon-carbon double bonds in their molecules, PUFA are believed to be highly reactive towards atmospheric oxidants such as OH and NO3 radicals and ozone, which will contribute to aerosol hygroscopicity and cloud condensation nuclei activity. Previous work from our group has shown that small carbonyls formed from the heterogeneous reaction of linoleic acid (LA) thin films with gas-phase O3. It is known that the formation of small carbonyls in the atmosphere is not only relevant to the atmospheric budget of volatile organic compounds but also to secondary organic aerosol formation. In the present study, using an online proton transfer reaction mass spectrometry (PTR-MS) and off-line gas chromatography-mass spectrometry (GC-MS) we again investigated carbonyl formation from the same reaction system, i.e. the heterogeneous ozonolysis of LA film. In addition to the previously reported carbonyls, malondialdehyde (MDA), a source of reactive oxygen species that is mutagenic, has been identified as a product for the first time. Small dicarbonyls, e.g. glyoxal, are expected to be formed from the further oxidation of MDA. In this presentation, the gas-phase chemistry of MDA with OH radicals using a newly built Teflon chamber in our group will also be presented.

  4. 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

  5. Controls on gas transfer velocities in a large river

    EPA Science Inventory

    The emission of biogenic gases from large rivers can be an important component of regional greenhouse gas budgets. However, emission rate estimates are often poorly constrained due to uncertainties in the air-water gas exchange rate. We used the floating chamber method to estim...

  6. Adaptive model-based control systems and methods for controlling a gas turbine

    NASA Technical Reports Server (NTRS)

    Brunell, Brent Jerome (Inventor); Mathews, Jr., Harry Kirk (Inventor); Kumar, Aditya (Inventor)

    2004-01-01

    Adaptive model-based control systems and methods are described so that performance and/or operability of a gas turbine in an aircraft engine, power plant, marine propulsion, or industrial application can be optimized under normal, deteriorated, faulted, failed and/or damaged operation. First, a model of each relevant system or component is created, and the model is adapted to the engine. Then, if/when deterioration, a fault, a failure or some kind of damage to an engine component or system is detected, that information is input to the model-based control as changes to the model, constraints, objective function, or other control parameters. With all the information about the engine condition, and state and directives on the control goals in terms of an objective function and constraints, the control then solves an optimization so the optimal control action can be determined and taken. This model and control may be updated in real-time to account for engine-to-engine variation, deterioration, damage, faults and/or failures using optimal corrective control action command(s).

  7. Assessment of DFT methods for studying acid gas capture by ionic liquids.

    PubMed

    García, Gregorio; Atilhan, Mert; Aparicio, Santiago

    2015-10-28

    For the first time, this work reports an analysis of the performance of Density Functional methods for studying acid gas capture (CO2 and SO2) by ionic liquids (ILs). The considered functionals were selected as representatives of the available families: pure GGA (PBE and BLYP), hybrid (PBE0 and B3LYP), hybrid meta-GGA (M06, M06-2X and M06-HF), long range corrected (LC-PBEPBE, CAM-B3LYP, ωB97X) and dispersion corrected (PBE-D2, B3LYP-D2 and ωB97XD). Likewise, HF and MP2 were also applied. Binding energies of cation-anion interacting pairs as well as IL-CO2 and IL-SO2 systems were calculated for a set of 54 ILs and compared against MP2/aug-cc-pvDZ. Unlike previously reported DFT benchmarks on ILs, which calculated binding energies through single point calculations on fixed geometries, properties in this work were calculated for geometries optimized at each theoretical level. DFT functionals that are suitable for describing ion-ion and ion-gas interactions were identified, considering both Coulombic forces and dispersion interactions. The reported results allowed us to infer relationships to the rational design of ILs for acid gas capture.

  8. OAS proteins and cGAS: unifying concepts in sensing and responding to cytosolic nucleic acids.

    PubMed

    Hornung, Veit; Hartmann, Rune; Ablasser, Andrea; Hopfner, Karl-Peter

    2014-08-01

    Recent discoveries in the field of innate immunity have highlighted the existence of a family of nucleic acid-sensing proteins that have similar structural and functional properties. These include the well-known oligoadenylate synthase (OAS) family proteins and the recently identified OAS homologue cyclic GMP-AMP (cGAMP) synthase (cGAS). The OAS proteins and cGAS are template-independent nucleotidyltransferases that, once activated by double-stranded nucleic acids in the cytosol, produce unique classes of 2'-5'-linked second messenger molecules, which - through distinct mechanisms - have crucial antiviral functions. 2'-5'-linked oligoadenylates limit viral propagation through the activation of the enzyme RNase L, which degrades host and viral RNA, and 2'-5'-linked cGAMP activates downstream signalling pathways to induce de novo antiviral gene expression. In this Progress article, we describe the striking functional and structural similarities between OAS proteins and cGAS, and highlight their roles in antiviral immunity.

  9. 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.

  10. Multiple Acid Sensors Control Helicobacter pylori Colonization of the Stomach

    PubMed Central

    Huang, Julie Y.; Goers Sweeney, Emily; Guillemin, Karen

    2017-01-01

    Helicobacter pylori’s ability to respond to environmental cues in the stomach is integral to its survival. By directly visualizing H. pylori swimming behavior when encountering a microscopic gradient consisting of the repellent acid and attractant urea, we found that H. pylori is able to simultaneously detect both signals, and its response depends on the magnitudes of the individual signals. By testing for the bacteria’s response to a pure acid gradient, we discovered that the chemoreceptors TlpA and TlpD are each independent acid sensors. They enable H. pylori to respond to and escape from increases in hydrogen ion concentration near 100 nanomolar. TlpD also mediates attraction to basic pH, a response dampened by another chemoreceptor TlpB. H. pylori mutants lacking both TlpA and TlpD (ΔtlpAD) are unable to sense acid and are defective in establishing colonization in the murine stomach. However, blocking acid production in the stomach with omeprazole rescues ΔtlpAD’s colonization defect. We used 3D confocal microscopy to determine how acid blockade affects the distribution of H. pylori in the stomach. We found that stomach acid controls not only the overall bacterial density, but also the microscopic distribution of bacteria that colonize the epithelium deep in the gastric glands. In omeprazole treated animals, bacterial abundance is increased in the antral glands, and gland colonization range is extended to the corpus. Our findings indicate that H. pylori has evolved at least two independent receptors capable of detecting acid gradients, allowing not only survival in the stomach, but also controlling the interaction of the bacteria with the epithelium. PMID:28103315

  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. Controlling fungus on channel catfish eggs with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is much interest in the use of peracetic acid (PAA) to treat pathogens in aquaculture. It is a relatively new compound and is approved for use in Europe, but not in the United States. This study determined the effectiveness of PAA for fungus control on channel catfish Ictalurus punctatus egg...

  13. Caged molecular beacons: controlling nucleic acid hybridization with light.

    PubMed

    Wang, Chunming; Zhu, Zhi; Song, Yanling; Lin, Hui; Yang, Chaoyong James; Tan, Weihong

    2011-05-28

    We have constructed a novel class of light-activatable caged molecular beacons (cMBs) that are caged by locking two stems with a photo-labile biomolecular interaction or covalent bond. With the cMBs, the nucleic acid hybridization process can be easily controlled with light, which offers the possibility for a high spatiotemporal resolution study of intracellular mRNAs.

  14. On the gas-particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

    NASA Astrophysics Data System (ADS)

    Liu, Jiumeng; Zhang, Xiaolu; Parker, Eric T.; Veres, Patrick R.; Roberts, James M.; de Gouw, Joost A.; Hayes, Patrick L.; Jimenez, Jose L.; Murphy, Jennifer G.; Ellis, Raluca A.; Huey, L. Greg; Weber, Rodney J.

    2012-10-01

    Gas and fine particle (PM2.5) phase formic acid concentrations were measured with online instrumentation during separate one-month studies in the summer of 2010 in Los Angeles (LA), CA, and Atlanta, GA. In both urban environments, median gas phase concentrations were on the order of a few ppbv (LA 1.6 ppbv, Atlanta 2.3 ppbv) and median particle phase concentrations were approximately tens of ng/m3 (LA 49 ng/m3, Atlanta 39 ng/m3). LA formic acid gas and particle concentrations had consistent temporal patterns; both peaked in the early afternoon and generally followed the trends in photochemical secondary gases. Atlanta diurnal trends were more irregular, but the mean diurnal profile had similar afternoon peaks in both gas and particle concentrations, suggesting a photochemical source in both cities. LA formic acid particle/gas (p/g) ratios ranged between 0.01 and 12%, with a median of 1.3%. No clear evidence that LA formic acid preferentially partitioned to particle water was observed, except on three overcast periods of suppressed photochemical activity. Application of Henry's Law to predict partitioning during these periods greatly under-predicted particle phase formate concentrations based on bulk aerosol liquid water content (LWC) and pH estimated from thermodynamic models. In contrast to LA, formic acid partitioning in Atlanta appeared to be more consistently associated with elevated relative humidity (i.e., aerosol LWC), although p/g ratios were somewhat lower, ranging from 0.20 to 5.8%, with a median of 0.8%. Differences in formic acid gas absorbing phase preferences between these two cities are consistent with that of bulk water-soluble organic carbon reported in a companion paper.

  15. Adipic acid enhanced flue gas desulfurization process for industrial boilers. Volume 2. Technical assessment. Project summary

    SciTech Connect

    Behrens, G.P.; Hargrove, O.W.

    1983-03-01

    The SO/sub 2/ removal efficiency with the adipic acid averaged 94.3% over a 30-day period, representing a significant improvement in the performance of the system using only limestone. Economic calculations for an industrial boiler adipic-acid-enhanced limestone FGD system indicate a slight reduction in both capital and operating expenses relative to a limestone-only system designed for 90% SO/sub 2/ control of 3.5% sulfur coal. The costs are competitive with the dual alkali system. The successful demonstration of the adipic-acid-enhanced limestone system increases the number of demonstrated technologies available to a potential user.

  16. Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

    PubMed

    Hurtado, Marcela; Lamsabhi, Al-Mokhtar; Mó, Otilia; Yáñez, Manuel; Guillemin, Jean-Claude

    2010-05-21

    The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C₅H₅⁻ anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C₅H₅ and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+δ)H(-δ) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C₅H₅X* (X = Mg, Ca) radicals.

  17. Determination of volatile fatty acids in wastewater by solvent extraction and gas chromatography

    NASA Astrophysics Data System (ADS)

    Mkhize, Nontando T.; Msagati, Titus A. M.; Mamba, Bhekie B.; Momba, Maggy

    The purpose of this study was to develop a liquid-liquid extraction method for the analysis of volatile fatty acids collected at the elutriation units of Unit 3, 4 and 5 at Johannesburg Water-Northern Works Wastewater Treatment Plant. Liquid-liquid extraction (LLE) method employing dichloromethane (DCM) and methyl-tert-butyl-ether (MTBE) as extracting solvents was used during the quantitative analysis of volatile fatty acids namely acetic, propionic, butyric, isobutyric, valeric, isovaleric and heptanoic acid. The detection of the extracts was by gas chromatography coupled to a mass spectrometer operating under electron ionization mode (GC-EI-MS). The results showed that MTBE was a better extraction solvent than DCM as it gave much higher recoveries (>5 folds). On the other hand, the overall reactor performance for all the three units in the period when the samples were collected, which was measured by the ratio of propionic to acetic acid was good since the ratio o did not exceed 1.4 with the exception of the samples collected on the 3rd of October where the ratio exceeded 1.4 significantly. The concentration of acetic acid, another indicator for the reactor performance in all three units was way below 800 mg/L thus the digester balance was on par.

  18. Fatal spontaneous Clostridium septicum gas gangrene: a possible association with iatrogenic gastric acid suppression.

    PubMed

    Wu, Yiru E; Baras, Alexander; Cornish, Toby; Riedel, Stefan; Burton, Elizabeth C

    2014-06-01

    The long-term use of proton pump inhibitors has been linked to an increased risk for the development of gastric polyps, hip fractures, pneumonia, and Clostridium difficile colitis. There is evidence that chronic acid suppression from long-term use of proton pump inhibitors poses some risk for the development of C difficile-associated diarrhea by decreasing the elimination of pathogenic microbes before reaching the lower gastrointestinal tract. Here we present a case of a 51-year-old woman with a recent history of abdominal pain and fever who presented to the emergency department with rapidly progressive spontaneous necrotizing fasciitis and gas gangrene and died within hours of presentation. Postmortem examination confirmed spreading tissue gas gangrene and myonecrosis. In addition, multiple intestinal ulcers containing Clostridium septicum were present at autopsy. This case illustrates a possible association between proton pump inhibitor therapy and fatal C septicum infection.

  19. Feed gas contaminant control in ion transport membrane systems

    DOEpatents

    Carolan, Michael Francis; Minford, Eric; Waldron, William Emil

    2009-07-07

    Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

  20. Control of Quaternary sea-level changes on gas seeps

    NASA Astrophysics Data System (ADS)

    Riboulot, Vincent; Thomas, Yannick; Berné, Serge; Jouet, Gwénaël.; Cattaneo, Antonio

    2014-07-01

    Gas seeping to the seafloor through structures such as pockmarks may contribute significantly to the enrichment of atmospheric greenhouse gases and global warming. Gas seeps in the Gulf of Lions, Western Mediterranean, are cyclical, and pockmark "life" is governed both by sediment accumulation on the continental margin and Quaternary climate changes. Three-dimensional seismic data, correlated to multi-proxy analysis of a deep borehole, have shown that these pockmarks are associated with oblique chimneys. The prograding chimney geometry demonstrates the syn-sedimentary and long-lasting functioning of the gas seeps. Gas chimneys have reworked chronologically constrained stratigraphic units and have functioned episodically, with maximum activity around sea level lowstands. Therefore, we argue that one of the main driving mechanisms responsible for their formation is the variation in hydrostatic pressure driven by relative sea level changes.

  1. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2001-11-06

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2001 through September 30, 2001. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub x} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. During the current period, American Electric Power (AEP) joined the project as an additional co-funder and as a provider of a host site for testing. This is the fourth reporting period for the subject Cooperative Agreement. During this period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Station. These tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Station), and a byproduct magnesium hydroxide slurry (both Gavin Station and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70 to 75% sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Station, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO{sub x

  2. Transition of RF internal antenna plasma by gas control

    SciTech Connect

    Hamajima, Takafumi; Yamauchi, Toshihiko; Kobayashi, Seiji; Hiruta, Toshihito; Kanno, Yoshinori

    2012-07-11

    The transition between the capacitively coupled plasma (CCP) and the inductively coupled plasma (ICP) was investigated with the internal radio frequency (RF) multi-turn antenna. The transition between them showed the hysteresis curve. The radiation power and the period of the self-pulse mode became small in proportion to the gas pressure. It was found that the ICP transition occurred by decreasing the gas pressure from 400 Pa.

  3. Thermal Battery Operating Gas Atmosphere Control and Heat Transfer Optimization

    DTIC Science & Technology

    2012-09-01

    Approved for public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The effects of gases and gas mixtures on global...highly effective in atmospheres of pure hydrogen and are potentially useful in mixtures of hydrogen and air. Barium chromate (BaCrO4) placed in contact...15 Figure 9. Gas gettering from a 79.6/20.4 volume percent hydrogen/air mixture

  4. Development of a Controlled Release of Salicylic Acid Loaded Stearic Acid-Oleic Acid Nanoparticles in Cream for Topical Delivery

    PubMed Central

    Woo, J. O.; Misran, M.; Lee, P. F.; Tan, L. P.

    2014-01-01

    Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs) with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release. PMID:24578624

  5. Control method for mixed refrigerant based natural gas liquefier

    SciTech Connect

    Kountz, Kenneth J.; Bishop, Patrick M.

    2003-01-01

    In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

  6. Controls on landfill gas collection efficiency: instantaneous and lifetime performance.

    PubMed

    Barlaz, Morton A; Chanton, Jeff P; Green, Roger B

    2009-12-01

    Estimates of landfill gas (LFG) collection efficiency are required to estimate methane emissions and the environmental performance of a solid waste landfill. The gas collection efficiency varies with time on the basis of the manner in which landfills are designed, operated, and regulated. The literature supports instantaneous collection efficiencies varying between 50% and near 100%, dependent on the cover type and the coverage of the LFG collection system. The authors suggest that the temporally weighted gas collection efficiency, which considers total gas production and collection over the landfill life, is the appropriate way to report collection efficiency. This value was calculated for a range of decay rates representative of refuse buried in arid and wet areas (i.e., >63.5 cm precipitation) and for bioreactor landfills. Temporally weighted collection efficiencies ranging from 67 to 91%, 62 to 86%, and 55 to 78% were calculated at decay rates of 0.02, 0.04, and 0.07 yr(-1), respectively. With aggressive gas collection, as would be implemented for a bioreactor landfill, estimated gas collection efficiency ranged from 84 to 67% at decay rates of 0.04 to 0.15 yr(-1), respectively.

  7. Seizure control by decanoic acid through direct AMPA receptor inhibition

    PubMed Central

    Chang, Pishan; Augustin, Katrin; Boddum, Kim; Williams, Sophie; Sun, Min; Terschak, John A.; Hardege, Jörg D.; Chen, Philip E.

    2016-01-01

    See Rogawski (doi:10.1093/awv369) for a scientific commentary on this article.  The medium chain triglyceride ketogenic diet is an established treatment for drug-resistant epilepsy that increases plasma levels of decanoic acid and ketones. Recently, decanoic acid has been shown to provide seizure control in vivo, yet its mechanism of action remains unclear. Here we show that decanoic acid, but not the ketones β-hydroxybutryate or acetone, shows antiseizure activity in two acute ex vivo rat hippocampal slice models of epileptiform activity. To search for a mechanism of decanoic acid, we show it has a strong inhibitory effect on excitatory, but not inhibitory, neurotransmission in hippocampal slices. Using heterologous expression of excitatory ionotropic glutamate receptor AMPA subunits in Xenopus oocytes, we show that this effect is through direct AMPA receptor inhibition, a target shared by a recently introduced epilepsy treatment perampanel. Decanoic acid acts as a non-competitive antagonist at therapeutically relevant concentrations, in a voltage- and subunit-dependent manner, and this is sufficient to explain its antiseizure effects. This inhibitory effect is likely to be caused by binding to sites on the M3 helix of the AMPA-GluA2 transmembrane domain; independent from the binding site of perampanel. Together our results indicate that the direct inhibition of excitatory neurotransmission by decanoic acid in the brain contributes to the anti-convulsant effect of the medium chain triglyceride ketogenic diet. PMID:26608744

  8. Field evaluation of natural gas and dry sorbent injection for MWC emissions control

    SciTech Connect

    Wohadlo, S; Abbasi, H; Cygan, D

    1993-10-01

    The Institute of Gas Technology (IGT), in cooperation with the Olmsted Waste-to-Energy Facility (OWEF) and with subcontracted engineering services from the Energy and Environmental Research Corporation (EER), has completed the detailed engineering and preparation of construction specifications for an Emissions Reduction Testing System (ERTS). The ERTS has been designed for retrofit to one of two 100-ton/day municipal waste combustors at the OWEF, located in Rochester, Minnesota. The purpose of the retrofit is to conduct a field evaluation of a combined natural gas and sorbent injection process (IGT`s METHANE de-TOX{sup SM}, IGT Patent No. 5,105,747) for reducing the emissions of oxides of nitrogen (NO{sub x}), hydrochloric acid (HCI), oxides of sulfur (SO{sub x}), carbon monoxide (CO), total hydrocarbons (THC), and chlorinated hydrocarbons (dioxin/furans). In addition, the design includes modifications for the control of heavy metals (HM). Development of the process should allow the waste-to-energy industry to meet the Federal New Source Performance Standards for these pollutants at significantly lower costs when compared to existing technology of Thermal deNO{sub x} combined with spray dryer scrubber/fabric filters. Additionally, the process should reduce boiler corrosion and increase both the thermal and power production efficiency of the facility.

  9. 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.

  10. Acid-base and surface energy characterization of grafted polyethylene using inverse gas chromatography.

    PubMed

    Uhlmann, Petra; Schneider, Steffen

    2002-09-06

    For a specific design of interfaces, i.e. in composites and blends, it is essential to know the surface thermodynamics of the components. Polyethylene grafted with maleic anhydride and maleic anhydride-styrene mixtures, respectively, was the component of interest of our investigations. Inverse gas chromatography (IGC) at infinite dilution was shown to be an appropriate method to evaluate the dispersive and acid-base surface characteristics although there is an influence of bulk absorption and morphology when performing IGC above the glass transition temperature of the polymer.

  11. [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.

  12. Control of immune response by amino acid metabolism.

    PubMed

    Grohmann, Ursula; Bronte, Vincenzo

    2010-07-01

    The interaction between pathogenic microorganisms and their hosts is regulated by reciprocal survival strategies, including competition for essential nutrients. Though paradoxical, mammalian hosts have learned to take advantage of amino acid catabolism for controlling pathogen invasion and, at the same time, regulating their own immune responses. In this way, ancient catabolic enzymes have acquired novel functions and evolved into new structures with highly specialized functions, which go beyond the struggle for survival. In this review, we analyze the evidence supporting a critical role for the metabolism of various amino acids in regulating different steps of both innate and adaptive immunity.

  13. Detection of lysergic acid diethylamide (LSD) in urine by gas chromatography-ion trap tandem mass spectrometry.

    PubMed

    Sklerov, J H; Kalasinsky, K S; Ehorn, C A

    1999-10-01

    A confirmatory method for the detection and quantitation of lysergic acid diethylamide (LSD) is presented. The method employs gas chromatography-tandem mass spectrometry (GC-MS-MS) using an internal ionization ion trap detector for sensitive MS-MS-in-time measurements of LSD extracted from urine. Following a single-step solid-phase extraction of 5 mL of urine, underivatized LSD can be measured with limits of quantitation and detection of 80 and 20 pg/mL, respectively. Temperature-programmed on-column injections of urine extracts were linear over the concentration range 20-2000 pg/mL (r2 = 0.999). Intraday and interday coefficients of variation were < 6% and < 13%, respectively. This procedure has been applied to quality-control specimens and LSD-positive samples in this laboratory. Comparisons with alternate GC-MS methods and extraction procedures are discussed.

  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. 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

  16. 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.

  17. 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.

  18. Gas hydrate formation in the deep sea: In situ experiments with controlled release of methane, natural gas, and carbon dioxide

    USGS Publications Warehouse

    Brewer, P.G.; Orr, F.M.; Friederich, G.; Kvenvolden, K.A.; Orange, D.L.

    1998-01-01

    We have utilized a remotely operated vehicle (ROV) to initiate a program of research into gas hydrate formation in the deep sea by controlled release of hydrocarbon gases and liquid CO2 into natural sea water and marine sediments. Our objectives were to investigate the formation rates and growth patterns of gas hydrates in natural systems and to assess the geochemical stability of the reaction products over time. The novel experimental procedures used the carrying capacity, imaging capability, and control mechanisms of the ROV to transport gas cylinders to depth and to open valves selectively under desired P-T conditions to release the gas either into contained natural sea water or into sediments. In experiments in Monterey Bay, California, at 910 m depth and 3.9??C water temperature we find hydrate formation to be nearly instantaneous for a variety of gases. In sediments the pattern of hydrate formation is dependent on the pore size, with flooding of the pore spaces in a coarse sand yielding a hydrate cemented mass, and gas channeling in a fine-grained mud creating a veined hydrate structure. In experiments with liquid CO2 the released globules appeared to form a hydrate skin as they slowly rose in the apparatus. An initial attempt to leave the experimental material on the sea floor for an extended period was partially successful; we observed an apparent complete dissolution of the liquid CO2 mass, and an apparent consolidation of the CH4 hydrate, over a period of about 85 days.

  19. Computational design of nucleic acid feedback control circuits.

    PubMed

    Yordanov, Boyan; Kim, Jongmin; Petersen, Rasmus L; Shudy, Angelina; Kulkarni, Vishwesh V; Phillips, Andrew

    2014-08-15

    The design of synthetic circuits for controlling molecular-scale processes is an important goal of synthetic biology, with potential applications in future in vitro and in vivo biotechnology. In this paper, we present a computational approach for designing feedback control circuits constructed from nucleic acids. Our approach relies on an existing methodology for expressing signal processing and control circuits as biomolecular reactions. We first extend the methodology so that circuits can be expressed using just two classes of reactions: catalysis and annihilation. We then propose implementations of these reactions in three distinct classes of nucleic acid circuits, which rely on DNA strand displacement, DNA enzyme and RNA enzyme mechanisms, respectively. We use these implementations to design a Proportional Integral controller, capable of regulating the output of a system according to a given reference signal, and discuss the trade-offs between the different approaches. As a proof of principle, we implement our methodology as an extension to a DNA strand displacement software tool, thus allowing a broad range of nucleic acid circuits to be designed and analyzed within a common modeling framework.

  20. Semi-continuous measurements of gas/particle partitioning of organic acids in a ponderosa pine forest using a MOVI-HRToF-CIMS

    NASA Astrophysics Data System (ADS)

    Yatavelli, R. L. N.; Stark, H.; Thompson, S. L.; Kimmel, J. R.; Cubison, M. J.; Day, D. A.; Campuzano-Jost, P.; Palm, B. B.; Thornton, J. A.; Jayne, J. T.; Worsnop, D. R.; Jimenez, J. L.

    2013-06-01

    Hundreds of gas and particle phase organic acids were measured in a rural ponderosa pine forest in Colorado, USA, during the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen - Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS). A recently developed Micro-Orifice Volatilization Impactor High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (MOVI-HRToF-CIMS) using acetate (CH3C(O)O-) as the reagent ion was used to selectively ionize and detect acids semi-continuously from 20-30 August 2011, with a measurement time resolution of ~1.5 h. At this site 98% of the organic acid mass is estimated to be in the gas-phase, with only ~2% in the particle phase. We investigated gas/particle partitioning, quantified as the fraction in the particle phase (Fp), of C1-C18 alkanoic acids, six known terpenoic acids and total bulk organic acids. Data were compared to the absorptive partitioning model and suggest that bulk organic acids at this site follow absorptive partitioning to the organic aerosol mass. The rapid response (<1-2 h) of partitioning to temperature changes for bulk acids suggests that kinetic limitations to equilibrium are minor, which is in contrast to conclusions of some recent laboratory and field studies, possibly due to lack of very low ambient relative humidities at this site. Time trends for partitioning of individual and groups of acids were mostly captured by the model, with varying degrees of absolute agreement. Species with predicted substantial fractions in both the gas and particle phases show better absolute agreement, while species with very low predicted fractions in one phase often show agreement on trends, but poor absolute agreement, potentially due to thermal decomposition, inlet adsorption, or other issues. Based on measurement-model comparison we conclude that species carbon number and oxygen content, together with ambient temperature control the volatility of organic acids and are good

  1. The adipic acid enhanced flue gas desulfurization process for industrial boilers. Volume 2. Technical assessment. Final report Feb 81-Feb 82

    SciTech Connect

    Behrens, G.P.; Hargrove, O.W. Jr

    1982-11-01

    The report gives results of an evaluation of an adipic acid enhanced limestone flue gas desulfurization (FGD) system on industrial boilers at Rickenbacker Air National Guard Base. The SO/sub 2/ removal efficiency with the adipic acid averaged 94.3% over a 30-day period. This represents a significant improvement in the performance of the system using only limestone. Economic calculations for an industrial boiler adipic acid enhanced limestone FGD system indicate a slight reduction in both capital and operating expenses relative to a limestone-only system designed for 90% SO2 control of 3.5% sulfur coal. The costs are competitive with those of the dual alkali system. The successful demonstration of the adipic acid enhanced limestone system increases the number of demonstrated technologies available to a potential user.

  2. Core acid treatment influence on well reservoir properties in Kazan oil-gas condensate field

    NASA Astrophysics Data System (ADS)

    Janishevskii, A.; Ezhova, A.

    2015-11-01

    The research involves investigation of the influence of hydrochloric acid (HCI-12%) and mud acid (mixture: HCl - 10% and HF - 3%) treatment on the Upper-Jurassic reservoir properties in Kazan oil-gas condensate field wells. The sample collection included three lots of core cylinders from one and the same depth (all in all 42). Two lots of core cylinders were distributed as following: first lot - reservoir properties were determined, and, then thin sections were cut off from cylinder faces; second lot- core cylinders were exposed to hydrochloric acid treatment, then, after flushing the reservoir properties were determined, and thin sections were prepared. Based on the quantitative petrographic rock analysis, involvin 42 thin sections, the following factors were determined: granulometric mineral composition, cement content, intergranular contacts and pore space structure. According to the comparative analysis of initial samples, the following was determined: content decrease of feldspar, clay and mica fragments, mica, clay and carbonate cement; increase of pore spaces while in the investigated samples- on exposure of rocks to acids effective porosity and permeability value range is ambiguous.

  3. Evidence in the formation of conjugated linoleic acids from thermally induced 9t12t linoleic acid: a study by gas chromatography and infrared spectroscopy.

    PubMed

    Christy, Alfred A

    2009-10-01

    Thermally induced isomerisation leading to the formation of conjugated linoleic acids (CLAs) has been observed for the first time during the thermal treatment of 9t12t fatty acid triacylglycerol, and methyl ester. Fifteen microlitre portions of the triacylglycerol sample containing 9t12t fatty acid (trilinoelaidin) were placed in micro glass ampoules and sealed under nitrogen, then subjected to thermal treatment at 250 degrees C. The glass ampoules were removed at regular time intervals, cut open, and the contents were analysed by infrared spectroscopy using a single reflectance attenuated total internal reflectance crystal accessory. The samples were then subjected to derivatisation into their methyl esters. The methyl esters of the isomerised fatty acids were analysed by gas chromatography. The same procedure was repeated with methyl ester samples containing 9t12t fatty acid (methyl linoelaidate). Each sample was subjected to infrared measurements and gas chromatographic analysis after appropriate dilution in heptane. The results show that the thermally induced isomerisation of 9t12t fatty acids from both triacylglycerol molecules and methyl esters give identical CLA profiles as those found for the thermally induced isomerisation of 9c12c fatty acids. The infrared spectrometry provides additional evidence confirming the formation of CLA acids during thermal treatment. A mechanism for the formation of the CLAs from 9t12t fatty acid molecules is also formulated for the first time. This mechanism complements the pathways of formation of CLAs from 9c12c fatty acids during thermal treatment.

  4. Controlling surface adsorption to enhance the selectivity of porphyrin based gas sensors

    NASA Astrophysics Data System (ADS)

    Evyapan, M.; Dunbar, A. D. F.

    2016-01-01

    This study reports an enhancement in the selectivity of the vapor sensing properties of free base porphyrin 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) Langmuir-Schaefer (LS) films. These sensors respond by changing color upon adsorption of the analyte gas to the sensor surface. The enhanced selectivity is achieved by adding selective barrier layers of 4-tert-Butylcalix[4]arene, 4-tert-Butylcalix[6]arene and 4-tert-Butylcalix[8]arene embedded in PMMA (Poly(methyl methacrylate)) on top of the porphyrin sensor films to control the gaseous adsorption onto the sensor surface. The Langmuir properties of EHO, PMMA and calix[n]arene monolayers were investigated by surface pressure-area (Π-A) isotherms in order to determine the most efficient transfer pressure. Six layer EHO films were transferred onto glass and silicon substrates to investigate their optical and structural characteristics. The three different calix[n]arenes were embedded within PMMA layers to act as the selective barrier layers which were deposited on top of the six layer EHO films. The different calix[n]arene molecules vary in size and each was mixed with PMMA in specific ratios in order to control the selectivity of the resulting barrier layers. Spectroscopic Ellipsometry (SE) and Atomic Force Microscopy (AFM) measurements were carried out to analyze the structure of the porous barrier layers. It was found that the orientation of the calix[8]arene molecules was well controlled within the Langmuir layers such that molecular ring lies flat on the EHO layers when deposited. However, the calix[6]arene and calix[4]arene molecules were quite not so reliably oriented. The sensor films (with and without the addition of the different selective barrier layers) were exposed to various carboxylic acid vapors. More specifically, acetic acid, butyric acid and hexanoic acid were chosen due to their different molecular sizes. The uncovered EHO films were highly sensitive to all the

  5. Identification of quantitative trait loci(QTL) controlling important fatty acids in peanut (Arachis hypogaea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acids play important role in controlling oil quality of peanut. In addition to the major fatty acids, oleic acid (C18:1) and linoleic acid (C18:2) accounting for about 80%, there are several minor fatty acids accounting for about 20% in peanut oil, such as palmitic acid (PA, C16:0), stearic (S...

  6. A new online exhaust gas monitoring system in hydrochloric acid regeneration of cold rolling mills.

    PubMed

    Tuo, Long; Zheng, Xiang; Chen, Xiong

    2015-07-07

    Measuring the content of hydrogen chloride (HCl) in exhaust gas used to take time and energy. In this paper, we introduce a new online monitoring system which can output real-time data to the monitoring center. The system samples and cools exhaust gas, and after a series of processing, it will be analyzed by a specific instrument. The core part of this system is remote terminal unit (RTU) which is designed on Cortex-A8 embedded architecture. RTU runs a scaled-down version of Linux which is a good choice of OS for embedded applications. It controls the whole processes, does data acquisition and data analysis, and communicates with monitoring center through Ethernet. In addition, through a software developed for windows, the monitoring process can be remotely controlled. The new system is quite beneficial for steel industry to do environment monitoring.

  7. Flue gas injection control of silica in cooling towers.

    SciTech Connect

    Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne

    2011-06-01

    Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.

  8. 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.

  9. Ab initio studies of aspartic acid conformers in gas phase and in solution

    NASA Astrophysics Data System (ADS)

    Chen, Mingliang; Lin, Zijing

    2007-10-01

    Systematic and extensive conformational searches of aspartic acid in gas phase and in solution have been performed. For the gaseous aspartic acid, a total of 1296 trial canonical structures and 216 trial zwitterionic structures were generated by allowing for all combinations of internal single-bond rotamers. All the trial structures were optimized at the B3LYP /6-311G* level and then subjected to further optimization at the B3LYP /6-311++G** level. A total of 139 canonical conformers were found, but no stable zwitterionic structure was found. The rotational constants, dipole moments, zero-point vibrational energies, harmonic frequencies, and vertical ionization energies of the canonical conformers were determined. Single-point energies were also calculated at the MP2/6-311++G** and CCSD /6-311++G** levels. The equilibrium distributions of the gaseous conformers at various temperatures were calculated. The proton affinity and gas phase basicity were calculated and the results are in excellent agreement with the experiments. The conformations in the solution were studied with different solvation models. The 216 trial zwitterionic structures were first optimized at the B3LYP /6-311G* level using the Onsager self-consistent reaction field model (SCRF) and then optimized at the B3LYP /6-311++G** level using the conductorlike polarized continuum model (CPCM) SCRF theory. A total of 22 zwitterions conformers were found. The gaseous canonical conformers were combined with the CPCM model and optimized at the B3LYP /6-311++G** level. The solvated zwitterionic and canonical structures were further examined by the discrete/SCRF model with one and two water molecules. The incremental solvation of the canonical and zwitterionic structures with up to six water molecules in gas phase was systematically examined. The studies show that combining aspartic acid with at least six water molecules in the gas phase or two water molecules and a SCRF solution model is required to provide

  10. 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.

  11. Control of Meloidogyne incognita Using Mixtures of Organic Acids

    PubMed Central

    Seo, Yunhee; Kim, Young Ho

    2014-01-01

    This study sought to control the root-knot nematode (RKN) Meloidogyne incognita using benign organo-chemicals. Second-stage juveniles (J2) of RKN were exposed to dilutions (1.0%, 0.5%, 0.2%, and 0.1%) of acetic acid (AA), lactic acid (LA), and their mixtures (MX). The nematode bodies were disrupted severely and moderately by vacuolations in 0.5% of MX and single organic acids, respectively, suggesting toxicity of MX may be higher than AA and LA. The mortality of J2 was 100% at all concentrations of AA and MX and only at 1.0% and 0.5% of LA, which lowered slightly at 0.2% and greatly at 0.1% of LA. This suggests the nematicidal activity of MX may be mostly derived from AA together with supplementary LA toxicity. MX was applied to chili pepper plants inoculated with about 1,000 J2, for which root-knot gall formations and plant growths were examined 4 weeks after inoculation. The root gall formation was completely inhibited by 0.5% MX and standard and double concentrations of fosthiazate; and inhibited 92.9% and 57.1% by 0.2% and 0.1% MX, respectively. Shoot height, shoot weight, and root weight were not significantly (P ≤ 0.05) different among all treatments and the untreated and non-inoculated controls. All of these results suggest that the mixture of the organic acids may have a potential to be developed as an eco-friendly nematode control agent that needs to be supported by the more nematode control experiments in fields. PMID:25506312

  12. 21. Interior view of citric acid air pollution control room ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Interior view of citric acid air pollution control room (also known as scrubber room) in Components Test Laboratory (T-27), looking southeast. Photograph shows upgraded instrumentation, piping, tanks, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

  13. Assessing sorbent injection mercury control effectiveness in flue gas streams

    USGS Publications Warehouse

    Carey, T.R.; Richardson, C.F.; Chang, R.; Meserole, F.B.; Rostam-Abadi, M.; Chen, S.

    2000-01-01

    One promising approach for removing mercury from coal-fired, utility flue gas involves the direct injection of mercury sorbents. Although this method has been effective at removing mercury in municipal waste incinerators, tests conducted to date on utility coal-fired boilers show that mercury removal is much more difficult in utility flue gas. EPRI is conducting research to investigate mercury removal using sorbents in this application. Bench-scale, pilot-scale, and field tests have been conducted to determine the ability of different sorbents to remove mercury in simulated and actual flue gas streams. This paper focuses on recent bench-scale and field test results evaluating the adsorption characteristics of activated carbon and fly ash and the use of these results to develop a predictive mercury removal model. Field tests with activated carbon show that adsorption characteristics measured in the lab agree reasonably well with characteristics measured in the field. However, more laboratory and field data will be needed to identify other gas phase components which may impact performance. This will allow laboratory tests to better simulate field conditions and provide improved estimates of sorbent performance for specific sites. In addition to activated carbon results, bench-scale and modeling results using fly ash are presented which suggest that certain fly ashes are capable of adsorbing mercury.

  14. 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).

  15. Geological Modeling and Fluid Flow Simulation of Acid Gas Storage, Nugget Sandstone, Moxa Arch, Wyoming

    NASA Astrophysics Data System (ADS)

    Li, S.; Zhang, Y.; Zhang, X.; Du, C.

    2009-12-01

    The Moxa Arch Anticline is a regional-scale northwest-trending uplift in western Wyoming where geological storage of acid gases (CO2, CH4, N2, H2S, He) from ExxonMobile's Shute Creek Gas Plant is under consideration. The Nugget Sandstone, a deep saline aquifer at depths exceeding 17,170 ft, is a candidate formation for acid gas storage. As part of a larger goal of determining site suitability, this study builds three-dimensional local to regional scale geological and fluid flow models for the Nugget Sandstone, its caprock (Twin Creek Limestone), and an underlying aquifer (Ankareh Sandstone), or together, the ``Nugget Suite''. For an area of 3000 square miles, geological and engineering data were assembled, screened for accuracy, and digitized, covering an average formation thickness of ~1700 feet. The data include 900 public-domain well logs (SP, Gamma Ray, Neutron Porosity, Density, Sonic, shallow and deep Resistivity, Lithology, Deviated well logs), 784 feet of core measurements (porosity and permeability), 4 regional geological cross sections, and 3 isopach maps. Data were interpreted and correlated for geological formations and facies, the later categorized using both Neural Network and Gaussian Hierarchical Clustering algorithms. Well log porosities were calibrated with core measurements, those of permeability estimated using formation-specific porosity-permeability transforms. Using conditional geostatistical simulations (first indicator simulation of facies, then sequential Gaussian simulation of facies-specific porosity), data were integrated at the regional-scale to create a geological model from which a local-scale simulation model surrounding the Shute Creek injection site was extracted. Based on this model, full compositional multiphase flow simulations were conducted with which we explore (1) an appropriate grid resolution for accurate acid gas predictions (pressure, saturation, and mass balance); (2) sensitivity of key geological and engineering

  16. Reactant gas composition for fuel cell potential control

    DOEpatents

    Bushnell, Calvin L.; Davis, Christopher L.

    1991-01-01

    A fuel cell (10) system in which a nitrogen (N.sub.2) gas is used on the anode section (11) and a nitrogen/oxygen (N.sub.2 /O.sub.2) gaseous mix is used on the cathode section (12) to maintain the cathode at an acceptable voltage potential during adverse conditions occurring particularly during off-power conditions, for example, during power plant shutdown, start-up and hot holds. During power plant shutdown, the cathode section is purged with a gaseous mixture of, for example, one-half percent (0.5%) oxygen (O.sub.2) and ninety-nine and a half percent (99.5%) nitrogen (N.sub.2) supplied from an ejector (21) bleeding in air (24/28) into a high pressure stream (27) of nitrogen (N.sub.2) as the primary or majority gas. Thereafter the fuel gas in the fuel processor (31) and the anode section (11) is purged with nitrogen gas to prevent nickel (Ni) carbonyl from forming from the shift catalyst. A switched dummy electrical load (30) is used to bring the cathode potential down rapidly during the start of the purges. The 0.5%/99.5% O.sub.2 /N.sub.2 mixture maintains the cathode potential between 0.3 and 0.7 volts, and this is sufficient to maintain the cathode potential at 0.3 volts for the case of H.sub.2 diffusing to the cathode through a 2 mil thick electrolyte filled matrix and below 0.8 volts for no diffusion at open circuit conditions. The same high pressure gas source (20) is used via a "T" juncture ("T") to purge the anode section and its associated fuel processor (31).

  17. Mechanisms of abscisic acid-mediated control of stomatal aperture.

    PubMed

    Munemasa, Shintaro; Hauser, Felix; Park, Jiyoung; Waadt, Rainer; Brandt, Benjamin; Schroeder, Julian I

    2015-12-01

    Drought stress triggers an increase in the level of the plant hormone abscisic acid (ABA), which initiates a signaling cascade to close stomata and reduce water loss. Recent studies have revealed that guard cells control cytosolic ABA concentration through the concerted actions of biosynthesis, catabolism as well as transport across membranes. Substantial progress has been made at understanding the molecular mechanisms of how the ABA signaling core module controls the activity of anion channels and thereby stomatal aperture. In this review, we focus on our current mechanistic understanding of ABA signaling in guard cells including the role of the second messenger Ca(2+) as well as crosstalk with biotic stress responses.

  18. 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.

  19. Bulk and surface controlled diffusion of fission gas atoms

    SciTech Connect

    Andersson, Anders D.

    2012-08-09

    Fission gas retention and release impact nuclear fuel performance by, e.g., causing fuel swelling leading to mechanical interaction with the clad, increasing the plenum pressure and reducing the gap thermal conductivity. All of these processes are important to understand in order to optimize operating conditions of nuclear reactors and to simulate accident scenarios. Most fission gases have low solubility in the fuel matrix, which is especially pronounced for large fission gas atoms such as Xe and Kr, and as a result there is a significant driving force for segregation of gas atoms to extended defects such as grain boundaries or dislocations and subsequently for nucleation of gas bubbles at these sinks. Several empirical or semi-empirical models have been developed for fission gas release in nuclear fuels, e.g. [1-6]. One of the most commonly used models in fuel performance codes was published by Massih and Forsberg [3,4,6]. This model is similar to the early Booth model [1] in that it applies an equivalent sphere to separate bulk UO{sub 2} from grain boundaries represented by the sphere circumference. Compared to the Booth model, it also captures trapping at grain boundaries, fission gas resolution and it describes release from the boundary by applying timedependent boundary conditions to the circumference. In this work we focus on the step where fission gas atoms diffuse from the grain interior to the grain boundaries. The original Massih-Forsberg model describes this process by applying an effective diffusivity divided into three temperature regimes. In this report we present results from density functional theory calculations (DFT) that are relevant for the high (D{sub 3}) and intermediate (D{sub 2}) temperature diffusivities of fission gases. The results are validated by making a quantitative comparison to Turnbull's [8-10] and Matzke's data [12]. For the intrinsic or high temperature regime we report activation energies for both Xe and Kr diffusion in UO

  20. Control of Cr6+ emissions from gas metal arc welding using a silica precursor as a shielding gas additive.

    PubMed

    Topham, Nathan; Wang, Jun; Kalivoda, Mark; Huang, Joyce; Yu, Kuei-Min; Hsu, Yu-Mei; Wu, Chang-Yu; Oh, Sewon; Cho, Kuk; Paulson, Kathleen

    2012-03-01

    Hexavalent chromium (Cr(6+)) emitted from welding poses serious health risks to workers exposed to welding fumes. In this study, tetramethylsilane (TMS) was added to shielding gas to control hazardous air pollutants produced during stainless steel welding. The silica precursor acted as an oxidation inhibitor when it decomposed in the high-temperature welding arc, limiting Cr(6+) formation. Additionally, a film of amorphous SiO(2) was deposited on fume particles to insulate them from oxidation. Experiments were conducted following the American Welding Society (AWS) method for fume generation and sampling in an AWS fume hood. The results showed that total shielding gas flow rate impacted the effectiveness of the TMS process. Increasing shielding gas flow rate led to increased reductions in Cr(6+) concentration when TMS was used. When 4.2% of a 30-lpm shielding gas flow was used as TMS carrier gas, Cr(6+) concentration in gas metal arc welding (GMAW) fumes was reduced to below the 2006 Occupational Safety and Health Administration standard (5 μg m(-3)) and the efficiency was >90%. The process also increased fume particle size from a mode size of 20 nm under baseline conditions to 180-300 nm when TMS was added in all shielding gas flow rates tested. SiO(2) particles formed in the process scavenged nanosized fume particles through intercoagulation. Transmission electron microscopy imagery provided visual evidence of an amorphous film of SiO(2) on some fume particles along with the presence of amorphous SiO(2) agglomerates. These results demonstrate the ability of vapor phase silica precursors to increase welding fume particle size and minimize chromium oxidation, thereby preventing the formation of hexavalent chromium.

  1. 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.

  2. Determination of benzoic acid in serum or plasma by gas chromatography-mass spectrometry (GC/MS).

    PubMed

    Knoblauch, Jeff M; Scott, David K; Smith, Laurie D; Garg, Uttam

    2010-01-01

    Nonketotic hyperglycinemia (NKH), a metabolic disorder due to defects in the glycine cleavage system, leads to the accumulation of toxic levels of glycine. Glycine levels in these patients may be lowered by sodium benzoate treatment. Benzoic acid binds to glycine to form hippurate, which is subsequently eliminated through the kidneys. At high concentrations, hippuric acid can crystallize in the kidneys and cause renal failure. Therefore, it is desirable to have benzoic acids concentrations within a therapeutic range. In the gas chromatography method described, the drug from the acidified serum or plasma sample is extracted using ethyl acetate. The organic phase containing drug is separated and dried under a stream of nitrogen. After trimethylsilyl derivatization, benzoic acid analysis is done on a gas chromatograph mass spectrometer. Quantitation of the drug in a sample is achieved by comparing responses of the unknown sample to the responses of the calibrators using selected ion monitoring. Benzoic acid D(5) is used as an internal standard.

  3. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2003-10-01

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period April 1, 2003 through September, 2003. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub x} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Group is the prime contractor. This is the eighth reporting period for the subject Cooperative Agreement. During previous reporting periods, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant), and a byproduct magnesium hydroxide slurry (both Gavin Plant and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO{sub x} control than at removing SO{sub 3} formed in the furnace. The SO{sub 3} removal results were presented in the semi

  4. Ring gas lasers with magneto-optical control for laser gyroscopy (invited paper)

    SciTech Connect

    Azarova, V V; Golyaev, Yu D; Dmitriev, Valentin G

    2000-02-28

    The main physical principles of the operation of ring gas lasers in the laser-gyroscope regime are examined. The influence of nonreciprocal effects on the operational parameters of ring gas lasers and the methods of controlling, with the aid of the nonreciprocal magneto-optical Zeeman effect, the parameters of these lasers used in gyroscopes are discussed. (laser gyroscopes)

  5. Design of a versatile pressure control system for gas targets in ion-atom collision studies

    NASA Astrophysics Data System (ADS)

    Fuelling, S.; Bruch, R.

    1993-06-01

    In this work, a unique gas target pressure control system is described which has been developed to measure state selective absolute EUV cross sections subsequent to electron and ion impact on gaseous targets. This system can be used in any type of gas phase experiment using positively or negatively charged and neutral particle beams interacting with atomic and molecular targets.

  6. Light-controlled gas permeability of mesoporous silica glass bearing photochromic spironaphthoxazine on its surface.

    PubMed

    Yagi, Shigeyuki; Minami, Naemi; Fujita, Junpei; Hyodo, Yutaka; Nakazumi, Hiroyuki; Yazawa, Tetsuo; Kami, Tetsuro; Ali, Aliyar Hyder

    2002-10-21

    N2 and CO2 gas permeability of mesoporous silica glass bearing photochromic indolinospironaphth[2,1-b][1,4]oxazine through a covalent linkage was controlled by photo-irradiation: the photo-isomerization of the spironaphthoxazine to the photomerocyanine form suppressed the gas permeation of the glass.

  7. 78 FR 51724 - California State Motor Vehicle Pollution Control Standards; Tractor-Trailer Greenhouse Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-21

    ... AGENCY California State Motor Vehicle Pollution Control Standards; Tractor-Trailer Greenhouse Gas...: The California Air Resources Board (CARB) has notified EPA that it has adopted a tractor-trailer greenhouse gas emission regulation applicable to new and in-use 53-foot and longer box-type trailers and...

  8. 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.

  9. The disposal of flue gas desulphurisation waste: sulphur gas emissions and their control.

    PubMed

    Raiswell, R; Bottrell, S H

    1991-06-01

    Flue gas desulphurisation (FGD) equipment to be fitted to UK coal-fired power stations will produce more than 0.8 Mtonnes of calcium sulphate, as gypsum. Most gypsum should be of commercial quality, but any low grade material disposed as waste has the potential to generate a range of sulphur gases, including H2S, COS, CS2, DMS and DMDS. Literature data from the USA indicates that well-oxidised waste with a high proportion of calcium sulphate (the main UK product of FGD) has relatively low emissions of sulphur gases, which are comparable to background levels from inland soils. However, sulphur gas fluxes are greatly enhanced where reducing conditions become established within the waste, hence disposal strategies should be formulated to prevent the sub-surface consumption of oxygen.

  10. Gas insulated transmission line with insulators having field controlling recesses

    DOEpatents

    Cookson, Alan H.; Pederson, Bjorn O.

    1984-01-01

    A gas insulated transmission line having a novel insulator for supporting an inner conductor concentrically within an outer sheath. The insulator has a recess contiguous with the periphery of one of the outer and inner conductors. The recess is disposed to a depth equal to an optimum gap for the dielectric insulating fluid used for the high voltage insulation or alternately disposed to a large depth so as to reduce the field at the critical conductor/insulator interface.

  11. Simulation in the design of gas pressure control equipment

    NASA Astrophysics Data System (ADS)

    Stoves, D.; Thompson, B.; Graham, P.

    1984-06-01

    To investigate the effects of changes in significant parameters of gas supply network pressure regulating equipment, a regulator model was established. The modeling of a supply network posed particular problems due to the large variation in actual pipework arrangements. Acoustic analysis was used to identify a representative characterization of a network. Use of computer simulation to establish appropriate response criteria and aid the design of a regulator to satisfy these criteria is described.

  12. Method of analysis at the U.S. Geological Survey California Water Science Center, Sacramento Laboratory - determination of haloacetic acid formation potential, method validation, and quality-control practices

    USGS Publications Warehouse

    Zazzi, Barbara C.; Crepeau, Kathryn L.; Fram, Miranda S.; Bergamaschi, Brian A.

    2005-01-01

    An analytical method for the determination of haloacetic acid formation potential of water samples has been developed by the U.S. Geological Survey California Water Science Center Sacramento Laboratory. The haloacetic acid formation potential is measured by dosing water samples with chlorine under specified conditions of pH, temperature, incubation time, darkness, and residual-free chlorine. The haloacetic acids formed are bromochloroacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, tribromoacetic acid, and trichloroacetic acid. They are extracted, methylated, and then analyzed using a gas chromatograph equipped with an electron capture detector. Method validation experiments were performed to determine the method accuracy, precision, and detection limit for each of the compounds. Method detection limits for these nine haloacetic acids ranged from 0.11 to 0.45 microgram per liter. Quality-control practices include the use of blanks, quality-control samples, calibration verification standards, surrogate recovery, internal standard, matrix spikes, and duplicates.

  13. Drift-Chamber Gas System Controls Development for the CEBAF Large Acceptance Spectrometer

    NASA Astrophysics Data System (ADS)

    Carroll, Thomas; Lack, Michael; Vineyard, Michael

    1997-04-01

    A control system for the drift-chamber gas system for the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, has been developed with the Experimental Physics and Industrial Control System (EPICS). EPICS is a sophisticated software tool for building real-time, distributed control systems. The gas system includes three RS- 232 instruments. The gas flow is controlled and monitored with two MKS 647A Multigas Controllers. Pressures are measured with three MKS 146B Vacuum Gauge Measurement and Control Systems. The Panametrics Moisture Image Series 1 and 3 are used to monitor temperatures and the concentrations of oxygen, water, and ethane. Many parameters are also monitored with XYCOM XVME- 560 analog input cards. A discussion of the development of the RS-232 device support software and the control system will be presented.

  14. 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.

  15. Control of gas contaminants in air streams through biofiltration

    SciTech Connect

    Holt, T.; Lackey, L.

    1996-11-01

    According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styrene concentration allowed in the work place is 50 ppm for up to a 10-hour work day during a 40-hour work week. The US EPA has classified styrene as one of the 189 hazardous air pollutants listed under Title 3 of the Clean Air Act Amendments to be reduced by a factor of 90% by the year 2000. Significant quantities of styrene are emitted to the atmosphere each year by boat manufacturers. A typical fiberglass boat manufacturing facility can emit over 273 metric tons/year of styrene. The concentration of styrene in the industrial exhaust gas ranges from 20 to 100 ppmv. Such dilute, high volume organically tainted air streams can make conventional abatement technologies such as thermal incineration, adsorption, or absorption technically incompetent or prohibitively expensive. An efficient, innovative, and economical means of remediating styrene vapors would be of value to industries and to the environment. Biofilter technology depends on microorganisms that are immobilized on the packing material in a solid phase reactor to remove or degrade environmentally undesirable compounds contaminating gas streams. The technology is especially successful for treating large volumes of air containing low concentrations of contaminants. The objective of this study was to investigate the feasibility of using biofiltration to treat waste gas streams containing styrene and to determine the critical design and operating parameters for such a system.

  16. Performance of a pilot-scale wet electrostatic precipitator for the control of sulfuric acid mist.

    PubMed

    Huang, Jiayu; Wang, Hongmei; Shi, Yingjie; Zhang, Fan; Dang, Xiaoqing; Zhang, Hui; Shu, Yun; Deng, Shuang; Liu, Yu

    2016-10-01

    The use of a wet electrostatic precipitator (WESP) is often regarded as a viable option to reduce sulfuric acid mist emitted from the wet flue gas desulfurization (WFGD) tower in coal-fired power plants. In this study, a pilot-scale wet electrostatic precipitator equipped with a wall-cooled collection electrode is investigated for the control of sulfuric acid mist from a simulated WFGD system. The results show that due to partial charging effect, the removal efficiency of sulfuric acid aerosol decreases when the aerosol size decreases to several tens of nanometers. Moreover, due to the plasma-induced effect, a large number of ultrafine sulfuric acid aerosols below 50 nm formed at a voltage higher than 24 kV inside the WESP. The percentages of submicron-sized aerosols significantly increase together with the voltage. To minimize the adverse plasma-induced effect, a WESP should be operated at a high gas velocity with an optimum high voltage. Even at a high flue gas velocity of 2.3 m s(-1), the mass concentration and the total number concentration of uncaptured sulfuric acid aerosols at the WESP outlet are as low as ca. 0.6 mg m(-3) and ca. 10(4) 1 cm(-3) at 28 kV, respectively. The corresponding removal efficiencies were respectively higher than 99.4 and 99.9 % and are very similar to that at 1.1 and 1.6 m s(-1). Moreover, the condensation-induced aerosol growth enhances the removal of sulfuric acid mist inside a WESP and enables a low emission concentration of ca. 0.65 mg m(-3) with a corresponding removal efficiency superior to 99.4 % even at a low voltage of 21 kV, and of ca. 0.35 mg m(-3) with a corresponding removal efficiency superior to 99.6 % at a higher voltage level of 26 kV.

  17. Sequential determination of triglycerides and free fatty acids in biological fluids by use of a continuous pretreatment module coupled to a gas chromatograph.

    PubMed

    Cárdenas, M S; Ballesteros, E; Gallego, M; Valcárcel, M

    1994-11-01

    A continuous system coupled to a gas-liquid chromatograph was used for the sequential determination of triglycerides and free fatty acids in serum and urine. The module provides compositional information and hence more detailed information on lipid metabolism changes in patients suffering metabolic disorders. Lipids in biological samples are manually extracted in methanol-n-hexane and introduced into the flow system; free fatty acids are then separated by retention on an ion-exchange resin and triglycerides (not retained) are transesterified with acetyl chloride in methanol. The resulting methyl esters are continuously injected into the gas chromatograph and determined by using a flame ionization detector. In a second step, retained free fatty acids are eluted and derivatized (also with acetyl chloride in methanol) and subsequently determined similarly as the triglycerides. The proposed method was applied to the determination of triglycerides in a lipid control serum; free fatty acids were determined in a human pool serum by the proposed method and compared with the volumetric method used in clinical practice. The results obtained in both instances showed good agreement between the results provided for triglycerides and free fatty acids. The proposed method was also applied to urine samples; a parallel recovery study was also made in order to assess the performance of the method.

  18. Exhaust gas bypass valve control for thermoelectric generator

    SciTech Connect

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

    2012-09-04

    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  19. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses

    PubMed Central

    Holm, Christian K.; Rahbek, Stine H.; Gad, Hans Henrik; Bak, Rasmus O.; Jakobsen, Martin R.; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K.; Sun, Chenglong; Thomsen, Martin K.; Laustsen, Anders; Nielsen, Camilla G.; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L.; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A.; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R.

    2016-01-01

    Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV. PMID:26893169

  20. Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.

    PubMed

    Holm, Christian K; Rahbek, Stine H; Gad, Hans Henrik; Bak, Rasmus O; Jakobsen, Martin R; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K; Sun, Chenglong; Thomsen, Martin K; Laustsen, Anders; Nielsen, Camilla G; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R

    2016-02-19

    Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV.

  1. Technology of Ultrasonic Control Of Gas-Shielded Welding Process

    NASA Astrophysics Data System (ADS)

    Solodsky, S. A.; Sarychev, V. D.; Borisov, I. S.

    2016-08-01

    A new approach to implementation of electrode metal transfer control under MAG, MIG welding is suggested. The process ensures control of thermal and crystallization processes, stabilizes the time of electrode metal drop formation. The results of the research allow formulating the basic criteria of electrode metal transfer control via ultrasonic exposure, determining the conditions of producing a more equilibrium structure of deposit metal.

  2. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL

    SciTech Connect

    Gary M. Blythe

    2003-06-01

    This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period October 1, 2002 through March 31, 2003. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO{sub x} selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Group is the prime contractor. This is the seventh reporting period for the subject Cooperative Agreement. During previous reporting periods, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant), and a byproduct magnesium hydroxide slurry (both Gavin Plant and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO{sub 3} formed across the SCR system installed on the unit for NO{sub x} control than at removing SO{sub 3} formed in the furnace. The SO3 removal results were presented in the semi

  3. Geological controls on the Storegga gas-hydrate system of the mid-Norwegian continental margin

    NASA Astrophysics Data System (ADS)

    Bünz, Stefan; Mienert, Jürgen; Berndt, Christian

    2003-04-01

    The geologic setting of the formerly glaciated mid-Norwegian continental margin exerts specific controls on the formation of a bottom-simulating reflector (BSR) and the inferred distribution of gas hydrates. On the continental slope the lithology of glacigenic debris flow deposits and pre-glacial basin deposits of the Kai Formation prevent gas-hydrate formation, because of reduced pore size, reduced water content and fine-grained sediment composition. Towards the continental shelf, the shoaling and pinch-out of the gas-hydrate stability zone terminates the area of gas-hydrate growth. These geological controls confine the occurrence of gas hydrates and ensuing formation of a BSR to a small zone along the northern flank of the Storegga submarine slide and the slide area itself. A BSR inside the slide area indicates a dynamically adjusting gas-hydrate system to post-slide pressure-temperature equilibrium conditions. These observations, together with widespread evidence for fluid flow and deep-seated hydrocarbon reservoirs, suggest that the formation of BSR and gas hydrates on the mid-Norwegian continental margin is dominated by an advection of gas from the strata distinctly beneath the gas-hydrate stability zone. Fluids migrate upward within the Naust Formation and are deflected laterally by hydrated sediments and less permeable layers. Gases continually accumulate at the top of the slope, where overpressure eventually results in the formation of blow-out pipes and consequent pockmark development on the seabed.

  4. Carboxylic acids in gas and PM2.5 particulate phase at a rural mountain site in northeastern United States

    NASA Astrophysics Data System (ADS)

    Hussain, M. M.; Khan, A. R.; Khwaja, H. A.

    2009-12-01

    Low molecular weight carboxylic acids are important constituents of the organic fraction of atmospheric particulate matter in rural and polluted regions. The knowledge on their source is sparse, however, and organic aerosols in general need to better characterized. Atmospheric gas- and particle-phase carboxylic acids (formic, acetic, pyruvic, glyoxalic, benzoaic, adipic, succinic, malonic, and oxalic) and related compounds were measured during August 2002 at a rural site, Whiteface Mountain, NY. Formic and acetic acids were present in the PM2.5 fraction and in the gas phase. Other seven carboxylic acids were below the detection limit in all samples. Formic and acetic acid were present in the atmosphere mostly in the gaseous form with less than 10% in the PM2.5 fraction. Concentrations of formic acid and acetic acid were in the 0.5 - 2.4 ppbv and 0.6 - 1.9 ppbv ranges, respectively. Formic-to-acetic acid ratios less than one (0.88) were recorded, likely due to an increase in acetic acid contribution from direct emissions. In the fine particulate mode (PM2.5 ) the concentrations for acetic acid and formic acid were 120 - 400 and 10 - 180 ng/m3 , respectively. Backward trajectory data indicate that air mass originated at midwestern region on August 5th and gradually moved towards north on August 9th. Correlation of formic acid with sulfate was investigated to interpret their possible secondary formation pathways. A strong correlation (0.73) was observed between formic acid and sulfate in PM2.5 particulates. Since the source of sulfate found at Whiteface Mountain widely accepted as anthropogenic, its association with formic acid indicated that the later might have anthropogenic source.

  5. [Determination of phthalic acid esters in textiles by solid phase extraction-gas chromatography].

    PubMed

    Niu, Zengyuan; Ye, Xiwen; Fang, Liping; Xue, Qiuhong; Sun, Zhongsong

    2006-09-01

    A method was established for the simultaneous determination of some phthalic acid esters, namely, dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPrP), dibutyl phthalate (DBP), diamyl phthalate (DAP), dihexyl phthalate (DHP), benzyln-butyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), dicyclohexyl phthalate (DCHP), di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) in textiles by solid phase extraction (SPE) coupled with gas chromatography (GC). The phthalic acid esters in textiles were extracted by Soxhlet extraction with hexane, the extracts were then cleaned up and enriched by a strong anion exchange (SAX) SPE cartridge. The parameters affecting the purification efficiency of SPE cartridge, such as solvent conditioning, rinsing, and elution, were studied. Conditioning with 5 mL hexane and rinsing with 3 mL isooctane were proved to be the optimal conditions. Of the several solvent ratios (ethylacetate in hexane) used for selective elution of phthalic acid esters from the SAX SPE cartridge, the 15% (v/v) content for ethylacetate in hexane gave the best result. Under the optimized conditions, the recoveries of phthalic acid esters for spiked standards (n=7) were 86.3%-102.7%, and the relative standard deviations (RSDs) were less than 5%. In this method the detection limits for DMP, DEP, DPrP, DBP, DAP, BBP, DCHP, DEHP, DNOP were all below 1 mg/kg, and the detection limits for DINP and DIDP were 1.74 mg/kg and 1.55 mg/kg respectively. This SPE-GC method is sensitive, accurate and suitable for the analysis of phthalate environmental hormones in textiles.

  6. Versatile computer-controlled system for characterization of gas sensing materials

    NASA Astrophysics Data System (ADS)

    Zhao, M.; Huang, J. X.; Wong, M. H.; Tang, Y. M.; Ong, C. W.

    2011-10-01

    Design of a system used for characterizing gas sensing materials is described. It is distinctive of being able to measure electrical and optical responses of a sample simultaneously, control a number of measurement parameters, perform fast exchange of gaseous environment, and be fully controlled automatically. These features make the system to be versatile in determining most concerned performance indexes of a gas sensing material (e.g., sensitivity, stability, selectivity, response/recovery times, etc.) as functions of various combinations of measurement conditions (e.g., gas concentrations, temperature, total pressure, content of interferants, photo assist, relative humidity, soaking time in a fixed gas concentration, and number of switching cycles in a dynamic test, etc.). Rationales of the designs associated with general gas sensing mechanics are discussed.

  7. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

    SciTech Connect

    A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

    1998-10-31

    This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500°C to 700°C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800°C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700°C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in

  8. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  9. 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.

  10. Gas-Phase Hydration Thermochemistry of Sodiated and Potassiated Nucleic Acid Bases

    NASA Astrophysics Data System (ADS)

    Wincel, Henryk

    2012-09-01

    Hydration reactions of sodiated and potassiated nucleic acid bases (uracil, thymine, cytosine, and adenine) produced by electrospray have been studied in a gas phase using the pulsed ion-beam high-pressure mass spectrometer. The thermochemical properties, ΔH o n , ΔS o n , and ΔG o n , for the hydrated systems were obtained from hydration equilibrium measurement. The structural aspects of the hydrated complexes are discussed in conjunction with available literature data. The correlation between water binding energies in the hydrated complexes and the corresponding metal ion affinities of nucleobases suggests that a significant (if not dominant) amount of the canonical structure of cytosine undergoes tautomerization during electrospray ionization, and the thermochemical values for cationized cytosine probably correspond to a mixture of tautomeric complexes.

  11. Gas-phase hydration thermochemistry of sodiated and potassiated nucleic acid bases.

    PubMed

    Wincel, Henryk

    2012-09-01

    Hydration reactions of sodiated and potassiated nucleic acid bases (uracil, thymine, cytosine, and adenine) produced by electrospray have been studied in a gas phase using the pulsed ion-beam high-pressure mass spectrometer. The thermochemical properties, ΔH(o)(n), ΔS(o)(n), and ΔG(o)(n), for the hydrated systems were obtained from hydration equilibrium measurement. The structural aspects of the hydrated complexes are discussed in conjunction with available literature data. The correlation between water binding energies in the hydrated complexes and the corresponding metal ion affinities of nucleobases suggests that a significant (if not dominant) amount of the canonical structure of cytosine undergoes tautomerization during electrospray ionization, and the thermochemical values for cationized cytosine probably correspond to a mixture of tautomeric complexes.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Optimization of a gas chromatography-mass spectrometry method with methyl chloroformate derivatization for quantification of amino acids in plant tissue.

    PubMed

    Vancompernolle, Bram; Croes, Kim; Angenon, Geert

    2016-04-01

    Rapid, easy and reliable quantification of amino acids is crucial in research on plant amino acid metabolism and nutritional improvement of crops via enrichment of essential amino acids. A recently reported analysis method, based on solid phase extraction (SPE), derivatization with methyl chloroformate and gas chromatography-mass spectrometry was optimized and tested on three-week-old Arabidopsis thaliana leaf tissues. Optimization of the SPE cleanup yielded recovery rates of minimum 95% for all amino acids (except arginine). Variations in accuracy and precision did not exceed 12.5%, except for cysteine, histidine and tryptophane, which were excluded from analysis. Quantification of overlapping peaks for isoleucine/threonine and proline/asparagine was possible by selection of two specific fragment ions for each amino acid. Of the 16 selected amino acids, 14 were quantified successfully in at least 75% of the samples, while methionine and tyrosine were only quantifiable in 6% and 42%, respectively. A case study on the aspartate super pathway confirmed the applicability of the optimized method on wild type and genetically modified plants: external supplementation of methionine or lysine yielded a 146-fold or 27-fold increase in the respective absolute amino acid levels compared with the control treatment. Induced expression of dhdps-r1 (a mutated lysine biosynthesis gene encoding a feedback insensitive enzyme) caused an 83-fold increase in absolute lysine levels.

  17. Analysis of naphthenic acid mixtures as pentafluorobenzyl derivatives by gas chromatography-electron impact mass spectrometry.

    PubMed

    Gutierrez-Villagomez, Juan Manuel; Vázquez-Martínez, Juan; Ramírez-Chávez, Enrique; Molina-Torres, Jorge; Trudeau, Vance L

    2017-01-01

    In this study, we report for the first time the efficiency of pentafluorobenzyl bromide (PFBBr) for naphthenic acid (NA) mixtures derivatization, and the comparison in the optimal conditions to the most common NAs derivatization reagents, BF3/MeOH and N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA). Naphthenic acids are carboxylic acid mixtures of petrochemical origin. These compounds are important for the oil industry because of their corrosive properties, which can damage oil distillation infrastructure. Moreover, NAs are commercially used in a wide range of products such as paint and ink driers, wood and fabric preservatives, fuel additives, emulsifiers, and surfactants. Naphthenic acids have also been found in sediments after major oils spills in the United States and South Korea. Furthermore, the toxicity of the oil sands process-affected water (OSPW), product of the oil sands extraction activities in Canada's oil sands, has largely been attributed to NAs. One of the main challenges for the chromatographic analysis of these mixtures is the resolution of the components. The derivatization optimization was achieved using surface response analysis with molar ratio and time as factors for derivatization signal yield. After gas chromatography-electron impact mass spectrometry (GC/EIMS) analysis of a mixture of NA standards, it was found that the signal produced by PFB-derivatives was 2.3 and 1.4 times higher than the signal produced by methylated and MTBS-derivatives, respectively. The pentafluorobenzyl derivatives have a characteristic fragment ion at 181m/z that is diagnostic for the differentiation of carboxylic and non-carboxylic acid components within mixtures. In the analysis of a Sigma and a Merichem derivatized oil extract NA mixtures, it was found that some peaks lack the characteristic fragment ion; therefore they are not carboxylic acids. Open column chromatography was used to obtain a hexane and a methanol fraction of the Sigma and

  18. 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.

  19. 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.

  20. Comparing Adrenaline with Tranexamic Acid to Control Acute Endobronchial Bleeding: A Randomized Controlled Trial

    PubMed Central

    Fekri, Mitra Samareh; Hashemi-Bajgani, Seyed Mehdy; Shafahi, Ahmad; Zarshenas, Rozita

    2017-01-01

    Background: Hemoptysis occurs due to either pulmonary diseases or bronchoscopy interventions. The aim of the present study was to compare the efficacy of the endobronchial instillation of adrenaline with that of tranexamic acid. Methods: Fifty patients were randomly selected as 2 double-blinded sample groups (n=25). In these patients, bleeding could not be controlled with cold saline lavage during bronchoscopy and they, therefore, required prescription of another medicine. Adrenaline (1 mg) in one group and tranexamic acid (500 mg) in the other group were diluted in 20 mL of normal saline and instilled through the bronchoscope. This technique was repeated 3 times at 90-second intervals, if necessary. In the case of persistent bleeding, 90 seconds after the last dose, a second medicine was given for bleeding control. Observation of clot through the bronchoscope meant that the bleeding had stopped. The efficacy of tranexamic acid and adrenaline was evaluated and then compared using the Mann–Whitney test. Results: The time of bleeding control had no significant difference between tranexamic acid and adrenaline (P=0.908). Another analysis was done to evaluate bleeding control with a second medicine; the results showed that 1 (4%) patient in the tranexamic acid and 8 (32%) in the adrenaline group needed the second medicine and there was no significant difference between the 2 groups (P=0.609). Conclusion: Our results suggested that tranexamic acid by endobronchial instillation was as efficient as adrenaline in controlling hemoptysis and required less frequent use of a second medicine. Trial Registration Number: IRCT2014120220188 PMID:28360438

  1. Experimental Investigations of the Effects of Acid Gas (H2S/CO2) Exposure under Geological Sequestration Conditions

    NASA Astrophysics Data System (ADS)

    Hawthorne, S. B.; Miller, D.; Kutchko, B. G.; Strazisar, B. R.

    2009-12-01

    Acid gas (mixed CO2 and H2S) injection into geological formations is increasingly used as a disposal option. In contrast to pure CO2 injection, there is little understanding of the possible effects of acid gases under geological sequestration conditions on exposed materials ranging from reactions with reservoir minerals to the stability of proppants injected to improve oil recovery to the possible failure of well-bore cements. The number of laboratory studies investigating effects of acid gas has been limited by safety concerns and the difficulty in preparing and maintaining single-phase H2S/CO2 mixtures under the experimental pressures and temperatures required. We have developed approaches using conventional syringe pumps and reactor vessels to prepare and maintain H2S/CO2 mixtures under relevant sequestration conditions of temperature, pressure, and exposure to water and dissolved salts. These methods have been used to investigate and compare the effects of acid gas with those of pure CO2 on several materials including reservoir cores, oil recovery proppants, and well-bore cements, as well as to investigate the rates of model reactions such as the conversion of Fe3O4 to pyrite. The apparatus and methods used to perform acid gas exposures and representative results from the various exposed materials will be presented.

  2. PC-based arc ignition and arc length control system for gas tungsten arc welding

    SciTech Connect

    Liu, Y. ); Cook, G.E.; Barnett, R.J.; Springfield, J.F. . School of Engineering)

    1992-10-01

    In this paper, a PC-based digital control system for gas tungsten arc welding (GTAW) is presented. This system controls the arc ignition process, the arc length, and the process of welding termination. A DT2818 made by Data Translation is used for interface and A/D and D/A conversions. The digital I/O ports of the DT2818 are used for control of wirefeed, shield gas, cooling water, welding power supply, etc. The DT2818 is housed in a PC. The welding signals and status are displayed on the screen for in-process monitoring. A user can control the welding process by the keyboard.

  3. 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.

  4. Consumers may not benefit from wellhead price controls on natural gas

    SciTech Connect

    Brown, S.P.A.

    1985-07-01

    Opposition to further decontrol of natural gas wellhead prices comes from concern that consumer prices would rise, but it is not clear that existing wellhead price controls have reduced consumer prices for natural gas. Empirical evidence suggests that consumers may be paying more and consuming less gas under federal price controls. Middlemen are charging more than the average wellhead price plus an efficient transportation charge. Government regulation of natural gas middlemen has not been effective in shifting benefits forward to consumers. At least some of the benefit is retained or dissipated by pipeline companies and their affiliates and by collection and distribution companies. Price controls have also led to a higher average wellhead price than would prevail in an unregulated market. 2 tables.

  5. Fuel flexibility via real-time Raman fuel-gas analysis for turbine system control

    NASA Astrophysics Data System (ADS)

    Buric, M.; Woodruff, S.; Chorpening, B.; Tucker, D.

    2015-06-01

    The modern energy production base in the U.S. is increasingly incorporating opportunity fuels such as biogas, coalbed methane, coal syngas, solar-derived hydrogen, and others. In many cases, suppliers operate turbine-based generation systems to efficiently utilize these diverse fuels. Unfortunately, turbine engines are difficult to control given the varying energy content of these fuels, combined with the need for a backup natural gas supply to provide continuous operation. Here, we study the use of a specially designed Raman Gas Analyzer based on capillary waveguide technology with sub-second response time for turbine control applications. The NETL Raman Gas Analyzer utilizes a low-power visible pump laser, and a capillary waveguide gas-cell to integrate large spontaneous Raman signals, and fast gas-transfer piping to facilitate quick measurements of fuel-gas components. A U.S. Department of Energy turbine facility known as HYPER (hybrid performance system) serves as a platform for apriori fuel composition measurements for turbine speed or power control. A fuel-dilution system is used to simulate a compositional upset while simultaneously measuring the resultant fuel composition and turbine response functions in real-time. The feasibility and efficacy of system control using the spontaneous Raman-based measurement system is then explored with the goal of illustrating the ability to control a turbine system using available fuel composition as an input process variable.

  6. 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.

  7. 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

    2015-08-03

    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.

  8. Robust control of speed and temperature in a power plant gas turbine.

    PubMed

    Najimi, Ebrahim; Ramezani, Mohammad Hossein

    2012-03-01

    In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions.

  9. Study of the ammonia (gas)-sulfuric acid (aerosol) reaction rate

    SciTech Connect

    McMurry, P.H.; Takano, H.; Anderson, G.R.

    1983-06-01

    An experimental study of the reaction rate between monodisperse sulfuric acid aerosols and ammonia gas is described. Reactions took place in a laminar flow reactor at 24/sup 0/C and 6% relative humidity, and reaction products were sampled from the core of the flow so that reaction times were well defined. For the data reported here, the reaction time was 5.0 +/- 0.5 s, ammonia concentrations ranged from 13 to 63 ppb, and particle sizes ranged from 0.03 to 0.2 ..mu..m. The extent of reaction was determined by comparing the hygroscopic and deliquescent properties of the product aerosols with known properties of aerosols consisting of internal mixtures of sulfuric acid and ammonium sulfate. It was found that the average fraction of ammonia-aerosol collisions that resulted in chemical reaction during neutralization decreased from 0.40 +/- 0.10 for 0.058-..mu..m particles to 0.18 +/- 0.03 for 0.10-..mu..m particles. Differential mobility analyzers were used for generating the monodisperse aerosols and also for measuring the hygroscopic and deliquescent properties of the product aerosols.

  10. 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.

  11. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Finn, John E.; LeVan, M. Douglas; Lung, Bernadette (Technical Monitor)

    2000-01-01

    Tests of a pre-prototype regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an adsorbent column have been performed at NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. During the normal operation mode, contaminants are removed from the air on the column. Regeneration of the column is performed on-line. During regeneration, contaminants are displaced and destroyed inside the closed oxidation loop. In this presentation we discuss initial experimental results for the performance of RAPS in the removal and treatment of several important spacecraft contaminant species from air.

  12. Electrochemical amperometric gas sensors for environmental monitoring and control

    NASA Technical Reports Server (NTRS)

    Venkatasetty, H. V.

    1990-01-01

    Theoretical considerations and experimental results regarding a unique class of vapor sensors are presented, and the sensors are compared to semiconductor-based sensors. The electrochemical sensors are based on nonaquaeous electrolytes, and gas-detection selectivity achieved by applying a known potential to the sensing electrode using a reference electrode and a counter electrode. Results are given regarding the detection of oxygen and carbon dioxide using one cell, the detection of 3-percent carbon dioxide in nitrogen, and the detection of carbon dioxide in air at percentages ranging from 3 to 6. The sensors are found to be effective in the detection of toxic chemical species including CO, NO2, and formaldehyde; the sensors are further found to require minimal power, operate over long periods of time, and function over a wide temperature range.

  13. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Qi, Nan; LeVan, M. Douglas; Finn, Cory K.; Finn, John E.; Luna, Bernadette (Technical Monitor)

    2000-01-01

    A regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an. adsorbent column into a closed oxidation loop is under development through cooperative R&D between Vanderbilt University and NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. Recent work has focused on fabrication and operation of a RAPS breadboard at NASA Ames, and on measurement of adsorption isotherm data for several important organic compounds at Vanderbilt. These activities support the use and validation of RAPS modeling software also under development at Vanderbilt, which will in turn be used to construct a prototype system later in the project.

  14. 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.

  15. A Novel Repair Technique for the Internal Thermal Control System Dual-Membrane Gas Trap

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Patel, Vipul; Reeves, Daniel R.; Holt, James M.

    2005-01-01

    A dual-membrane gas trap is currently used to remove gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the gas bubbles. The inner hydrophobic fiber allows the trapped gas bubbles to pass through and vent to the ambient atmosphere in the cabin. The gas trap was designed to last for the entire lifetime of the ISS, and therefore was not designed to be repaired. However, repair of these gas traps is now a necessity due to contamination from the on-orbit ITCS fluid and other sources on the ground as well as a limited supply of flight gas traps. This paper describes a novel repair technique that has been developed that will allow the refurbishment of contaminated gas traps and their return to flight use.

  16. Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    A dual-membrane gas trap is currently used to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the NCG. The inner hydrophobic fiber allows the trapped NCG to pass through and vent to the ambient atmosphere in the cabin. The purpose of the gas trap is to prevent gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump, and the current gas trap has performed flawlessly in this regard. However, because of actual operational conditions on-orbit, its gas removal performance and operational lifetime have been affected. This paper discusses experiences with several of these dual- membrane gas traps, including on-orbit gas venting rate, effects due to the presence of nickel in the ITCS coolant, and subsequent refurbishing to remove the nickel from the gas trap.

  17. 21 CFR 866.5910 - Quality control material for cystic fibrosis nucleic acid assays.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... nucleic acid assays. 866.5910 Section 866.5910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Test Systems § 866.5910 Quality control material for cystic fibrosis nucleic acid assays. (a) Identification. Quality control material for cystic fibrosis nucleic acid assays. A quality control material...

  18. 21 CFR 866.5910 - Quality control material for cystic fibrosis nucleic acid assays.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... nucleic acid assays. 866.5910 Section 866.5910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Test Systems § 866.5910 Quality control material for cystic fibrosis nucleic acid assays. (a) Identification. Quality control material for cystic fibrosis nucleic acid assays. A quality control material...

  19. 21 CFR 866.5910 - Quality control material for cystic fibrosis nucleic acid assays.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... nucleic acid assays. 866.5910 Section 866.5910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Test Systems § 866.5910 Quality control material for cystic fibrosis nucleic acid assays. (a) Identification. Quality control material for cystic fibrosis nucleic acid assays. A quality control material...

  20. 21 CFR 866.5910 - Quality control material for cystic fibrosis nucleic acid assays.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... nucleic acid assays. 866.5910 Section 866.5910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Test Systems § 866.5910 Quality control material for cystic fibrosis nucleic acid assays. (a) Identification. Quality control material for cystic fibrosis nucleic acid assays. A quality control material...

  1. 21 CFR 866.5910 - Quality control material for cystic fibrosis nucleic acid assays.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... nucleic acid assays. 866.5910 Section 866.5910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Test Systems § 866.5910 Quality control material for cystic fibrosis nucleic acid assays. (a) Identification. Quality control material for cystic fibrosis nucleic acid assays. A quality control material...

  2. Quorum sensing-controlled buoyancy through gas vesicles: Intracellular bacterial microcompartments for environmental adaptation.

    PubMed

    Ramsay, Joshua P; Salmond, George P C

    2012-01-01

    Gas vesicles are gas-filled microcompartments produced by many cyanobacteria and haloarchaea to regulate buoyancy and control positioning in the water column. Recently we identified the first case of gas vesicle production by a member of the Enterobacteriaceae, Serratia sp ATCC39006. Gas vesicle production enabled colonisation of the air-liquid interface and was positively regulated in low-oxygen conditions, suggesting development of these intracellular organelles is an adpative mechanism facilitating migration to the water surface. Vesicle production was also regulated by the intercellular communication molecule N‑butanoyl-L‑homoserine lactone (BHL) showing that gas vesicle production is controlled at the population level, through quorum sensing, with BHL acting as a morphogen. Gas vesicle production was also reciprocally regulated with flagella-driven swarming motility by the global regulatory protein RsmA, suggesting a fork in the regulatory pathway that controls induction of these distinct modes of mobility. Here we discuss these findings in the context of the interesting physiology of Serratia 39006 and highlight future prospects for gas vesicle research in this highly tractable strain.

  3. Use of Gas-Liquid Chromatography to Determine the End Products of Growth of Lactic Acid Bacteria

    PubMed Central

    Thornhill, Patrick J.; Cogan, Timothy M.

    1984-01-01

    A simple gas-liquid chromatographic procedure for analyzing ethanol, acetic acid, acetoin, and racemic and meso-2,3-butylene glycol in broth media is described. Overnight broth cultures were filtered or centrifuged, and the filtrate or supernatant was treated with formic acid to aid separation of volatile fatty acids. Samples were then directly analyzed by gas-liquid chromatography on a 20% Tween 80-Chromosorb W-AW column and propionic acid as an internal standard. A complete analysis took ca. 8 min. The method can be used to distinguish homofermentative from heterofermentative lactic acid bacteria based on the level of ethanol produced and citrate-utilizing from non-citrate-utilizing lactic acid bacteria based on the levels of acetic acid produced. The method also has potential in distinguishing other bacterial fermentations. Of the 13 species of lactic acid bacteria tested, Streptococcus lactis subsp. diacetylactis was the major producer of 2,3-butylene glycol (total range, 0.3 to 3.5 mM), and, except for strain DRC1, both the racemic and meso isomers were produced in approximately equal amounts. PMID:16346562

  4. Experimental and theoretical studies of the interaction of gas phase nitric acid and water with a self-assembled monolayer.

    PubMed

    Moussa, S G; Stern, A C; Raff, J D; Dilbeck, C W; Tobias, D J; Finlayson-Pitts, B J

    2013-01-14

    Nitric acid in air is formed by atmospheric reactions of oxides of nitrogen and is removed primarily through deposition to surfaces, either as the gas or after conversion to particulate nitrate. Many of the surfaces and particles have organic coatings, but relatively little is known about the interaction of nitric acid with organic films. We report here studies of the interaction of gaseous HNO(3) with a self-assembled monolayer (SAM) formed by reacting 7-octenyltrichlorosilane [H(2)C=CH(CH(2))(6)SiCl(3)] with the surface of a germanium infrared-transmitting attenuated total reflectance (ATR) crystal that was coated with a thin layer of silicon oxide (SiO(x)). The SAM was exposed at 298 ± 2 K to dry HNO(3) in a flow of N(2), followed by HNO(3) in humid N(2) at a controlled relative humidity (RH) between 20-90%. For comparison, similar studies were carried out using a similar crystal without the SAM coating. Changes in the surface were followed using Fourier transform infared spectroscopy (FTIR). In the case of the SAM-coated crystal, molecular HNO(3) and smaller amounts of NO(3)(-) ions were observed on the surface upon exposure to dry HNO(3). Addition of water vapor led to less molecular HNO(3) and more H(3)O(+) and NO(3)(-) complexed to water, but surprisingly, molecular HNO(3) was still evident in the spectra up to 70% RH. This suggests that part of the HNO(3) observed was initially trapped in pockets within the SAM and shielded from water vapor. After increasing the RH to 90% and then exposing the film to a flow of dry N(2), molecular nitric acid was regenerated, as expected from recombination of protons and nitrate ions as water evaporated. The nitric acid ultimately evaporated from the film. On the other hand, exposure of the SAM to HNO(3) and H(2)O simultaneously gave only hydronium and nitrate ions. Molecular dynamics simulations of defective SAMs in the presence of HNO(3) and water predict that nitric acid intercalates in defects as a complex with a

  5. A Gas Chromatographic Method for the Determination of Aldose and Uronic Acid Constituents of Plant Cell Wall Polysaccharides 1

    PubMed Central

    Jones, Thomas M.; Albersheim, Peter

    1972-01-01

    A major problem in determining the composition of plant cell wall polysaccharides has been the lack of a suitable method for accurately determining the amounts of galacturonic and glucuronic acids in such polymers. A gas chromatographic method for aldose analysis has been extended to include uronic acids. Cell wall polysaccharides are depolymerized by acid hydrolysis followed by treatment with a mixture of fungal polysaccharide-degrading enzymes. The aldoses and uronic acids released by this treatment are then reduced with NaBH4 to alditols and aldonic acids, respectively. The aldonic acids are separated from the alditols with Dowex-1 (acetate form) ion exchange resin, which binds the aldonic acids. The alditols, which do not bind, are washed from the resin and then acetylated with acetic anhydride to form the alditol acetate derivatives. The aldonic acids are eluted from the resin with HCl. After the resin has been removed, the HCl solution of the aldonic acids is evaporated to dryness, converting the aldonic acids to aldonolactones. The aldonolactones are reduced with NaBH4 to the corresponding alditols, dried and acetylated. The resulting alditol acetate mixtures produced from the aldoses and those from the uronic acids are analyzed separately by gas chromatography. This technique has been used to determine the changes in composition of Red Kidney bean (Phaseolus vulgaris) hypocotyl cell walls during growth, and to compare the cell wall polysaccharide compositions of several parts of bean plants. Galacturonic acid is found to be a major component of all the cell wall polysaccharides examined. PMID:16658086

  6. Methane emissions from process equipment at natural gas production sites in the United States: pneumatic controllers.

    PubMed

    Allen, David T; Pacsi, Adam P; Sullivan, David W; Zavala-Araiza, Daniel; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Sawyer, Robert F; Seinfeld, John H

    2015-01-06

    Emissions from 377 gas actuated (pneumatic) controllers were measured at natural gas production sites and a small number of oil production sites, throughout the United States. A small subset of the devices (19%), with whole gas emission rates in excess of 6 standard cubic feet per hour (scf/h), accounted for 95% of emissions. More than half of the controllers recorded emissions of 0.001 scf/h or less during 15 min of measurement. Pneumatic controllers in level control applications on separators and in compressor applications had higher emission rates than controllers in other types of applications. Regional differences in emissions were observed, with the lowest emissions measured in the Rocky Mountains and the highest emissions in the Gulf Coast. Average methane emissions per controller reported in this work are 17% higher than the average emissions per controller in the 2012 EPA greenhouse gas national emission inventory (2012 GHG NEI, released in 2014); the average of 2.7 controllers per well observed in this work is higher than the 1.0 controllers per well reported in the 2012 GHG NEI.

  7. Vapor-alcohol control tests with compressed ethanol-gas mixtures: scientific basis and actual performance.

    PubMed

    Dubowski, K M; Essary, N A

    1996-10-01

    Commercial compressed vapor-alcohol mixtures ("dry gas") were evaluated to ascertain their suitability for control tests in breath-alcohol analysis. Dry gas control tests were conducted at nominal vapor-alcohol concentrations (VACs) of 0.045, 0.085, and 0.105 g/210 L (n = 50 at each VAC) with Alcotest 7110 MK III and Intoxilyzer 1400 evidential breath-alcohol testers. The measurement results were analyzed by standard statistical methods, and their correlation with certified dry gas VAC target values was examined. Also measured and examined statistically were the VACs of National Institute of Standards and Technology-traceable Research Gas mixtures (dry gas) ethanol standards at 97.8 and 198 ppm (n = 30-50 at each VAC). With the Alcotest 7110 MK III programmed to report VACs normalized to standard atmospheric pressure at 760 torr and the intoxilyzer 1400 programmed to report VACs at ambient atmospheric pressure, the predicted effects of ambient atmospheric pressure were confirmed experimentally. We developed and validated the following conversion factor for VAC units at 34 degrees C and 760 torr: ppm/2605 = g/210 L and g/210 L x 2605 = ppm. We found that the dry gas vapor-alcohol control samples conformed to established formal specifications and concluded that they compared favorably with simulator effluents for control tests of breath-alcohol analyzers, which are capable of adjusting VAC results for ambient atmospheric pressure.

  8. A solenoid failure detection system for cold gas attitude control jet valves

    NASA Technical Reports Server (NTRS)

    Johnston, P. A.

    1970-01-01

    The development of a solenoid valve failure detection system is described. The technique requires the addition of a radioactive gas to the propellant of a cold gas jet attitude control system. Solenoid failure is detected with an avalanche radiation detector located in the jet nozzle which senses the radiation emitted by the leaking radioactive gas. Measurements of carbon monoxide leakage rates through a Mariner type solenoid valve are presented as a function of gas activity and detector configuration. A cylindrical avalanche detector with a factor of 40 improvement in leak sensitivity is proposed for flight systems because it allows the quantity of radioactive gas that must be added to the propellant to be reduced to a practical level.

  9. Structurally controlled and aligned tight gas reservoir compartmentalization in the San Juan and Piceance Basins

    SciTech Connect

    Decker, A.D.; Kuuskraa, V.A.; Klawitter, A.L.

    1995-10-01

    Recurrent basement faulting is the primary controlling mechanism for aligning and compartmentalizing upper Cretaceous aged tight gas reservoirs of the San Juan and Piceance Basins. Northwest trending structural lineaments that formed in conjunction with the Uncompahgre Highlands have profoundly influenced sedimentation trends and created boundaries for gas migration; sealing and compartmentalizing sedimentary packages in both basins. Fractures which formed over the structural lineaments provide permeability pathways which allowing gas recovery from otherwise tight gas reservoirs. Structural alignments and associated reservoir compartments have been accurately targeted by integrating advanced remote sensing imagery, high resolution aeromagnetics, seismic interpretation, stratigraphic mapping and dynamic structural modelling. This unifying methodology is a powerful tool for exploration geologists and is also a systematic approach to tight gas resource assessment in frontier basins.

  10. Control method for turbocharged diesel engines having exhaust gas recirculation

    DOEpatents

    Kolmanovsky, Ilya V.; Jankovic, Mrdjan J; Jankovic, Miroslava

    2000-03-14

    A method of controlling the airflow into a compression ignition engine having an EGR and a VGT. The control strategy includes the steps of generating desired EGR and VGT turbine mass flow rates as a function of the desired and measured compressor mass airflow values and exhaust manifold pressure values. The desired compressor mass airflow and exhaust manifold pressure values are generated as a function of the operator-requested fueling rate and engine speed. The EGR and VGT turbine mass flow rates are then inverted to corresponding EGR and VGT actuator positions to achieve the desired compressor mass airflow rate and exhaust manifold pressure. The control strategy also includes a method of estimating the intake manifold pressure used in generating the EGR valve and VGT turbine positions.

  11. 40 CFR 80.32 - Controls applicable to liquefied petroleum gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... petroleum gas retailers and wholesale purchaser-consumers. 80.32 Section 80.32 Protection of Environment... Controls and Prohibitions § 80.32 Controls applicable to liquefied petroleum gas retailers and wholesale...,660 gallons of liquefied petroleum gas per month shall equip each pump from which liquefied...

  12. 40 CFR 80.32 - Controls applicable to liquefied petroleum gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... petroleum gas retailers and wholesale purchaser-consumers. 80.32 Section 80.32 Protection of Environment... Controls and Prohibitions § 80.32 Controls applicable to liquefied petroleum gas retailers and wholesale...,660 gallons of liquefied petroleum gas per month shall equip each pump from which liquefied...

  13. 40 CFR 80.32 - Controls applicable to liquefied petroleum gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... petroleum gas retailers and wholesale purchaser-consumers. 80.32 Section 80.32 Protection of Environment... Controls and Prohibitions § 80.32 Controls applicable to liquefied petroleum gas retailers and wholesale...,660 gallons of liquefied petroleum gas per month shall equip each pump from which liquefied...

  14. 40 CFR 80.32 - Controls applicable to liquefied petroleum gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... petroleum gas retailers and wholesale purchaser-consumers. 80.32 Section 80.32 Protection of Environment... Controls and Prohibitions § 80.32 Controls applicable to liquefied petroleum gas retailers and wholesale...,660 gallons of liquefied petroleum gas per month shall equip each pump from which liquefied...

  15. 40 CFR 80.32 - Controls applicable to liquefied petroleum gas retailers and wholesale purchaser-consumers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... petroleum gas retailers and wholesale purchaser-consumers. 80.32 Section 80.32 Protection of Environment... Controls and Prohibitions § 80.32 Controls applicable to liquefied petroleum gas retailers and wholesale...,660 gallons of liquefied petroleum gas per month shall equip each pump from which liquefied...

  16. 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.

  17. Greenhouse gas emissions control by economic incentives: Survey and analysis

    SciTech Connect

    South, D.W.; Kosobud, R.F.; Quinn, K.G.

    1991-01-01

    This paper presents a survey of issues and concerns raised in recent literature on the application of market-based approaches to greenhouse effect policy with an emphasis on tradeable emission permits. The potential advantages of decentralized decision-making -- cost-effectiveness or allocation efficiency, stimulation of innovations, and political feasibility are discussed. The potential difficulties of data recording, monitoring, enforcement, and of creating viable emission permit contracts and markets are examined. Special attention is given to the problem of designing a greenhouse effect policy that is cost-effective over time, a problem that has been given little attention to date. Proposals to reduce or stabilize greenhouse gas emission (especially CO{sub 2}) in the short run require high carbon tax rates or permit prices and impose heavy adjustment costs on the fossil fuel industry. A more cost-effective time path of permit prices is proposed that achieves the same long-run climate change stabilization goals. 21 refs., 3 figs.

  18. Greenhouse gas emissions control by economic incentives: Survey and analysis

    SciTech Connect

    South, D.W.; Kosobud, R.F.; Quinn, K.G.

    1991-12-31

    This paper presents a survey of issues and concerns raised in recent literature on the application of market-based approaches to greenhouse effect policy with an emphasis on tradeable emission permits. The potential advantages of decentralized decision-making -- cost-effectiveness or allocation efficiency, stimulation of innovations, and political feasibility are discussed. The potential difficulties of data recording, monitoring, enforcement, and of creating viable emission permit contracts and markets are examined. Special attention is given to the problem of designing a greenhouse effect policy that is cost-effective over time, a problem that has been given little attention to date. Proposals to reduce or stabilize greenhouse gas emission (especially CO{sub 2}) in the short run require high carbon tax rates or permit prices and impose heavy adjustment costs on the fossil fuel industry. A more cost-effective time path of permit prices is proposed that achieves the same long-run climate change stabilization goals. 21 refs., 3 figs.

  19. How phosphorus limitation can control climatic gas emission

    NASA Astrophysics Data System (ADS)

    Gypens, Nathalie; Borges, Alberto V.; Speeckaert, Gaelle; Ghyoot, Caroline

    2015-04-01

    Anthropogenic activities severely increased river nutrient [nitrogen (N) and phosphorus (P)] loads to European coastal areas. However, specific nutrient reduction policies implemented since the late 1990's have considerably reduced P loads, while N is maintained. In the Southern North Sea, the resulting N: P: Si imbalance (compared to phytoplankton requirements) stimulated the growth of Phaeocystis colonies modifying the functioning of the ecosystem and, therefore, the carbon cycle but also the biogenic sulphur cycle, Phaeocystis being a significant producer of DMSP (dimethylsulphide propionate), the precursor of dimethylsulfide (DMS). In this application, the mechanistic MIRO-BIOGAS model is used to investigate the effects of changing N and P loads on ecosystem structure and their impact on DMS and CO2 emissions. In particular, competition for P between phytoplankton groups (diatoms vs Phaeocystis colonies) but also between phytoplankton and bacteria is explored. The ability of autotroph and heterotroph organism to use dissolved organic phosphorus (DOP) as P nutrient source is also explored and its effect on climatic gas emission estimated. Simulations were done from 1950 to 2010 and different nutrient limiting conditions are analyzed.

  20. Fabrication and test of digital output interface devices for gas turbine electronic controls

    NASA Technical Reports Server (NTRS)

    Newirth, D. M.; Koenig, E. W.

    1978-01-01

    A program was conducted to develop an innovative digital output interface device, a digital effector with optical feedback of the fuel metering valve position, for future electronic controls for gas turbine engines. A digital effector (on-off solenoids driven directly by on-off signals from a digital electronic controller) with optical position feedback was fabricated, coupled with the fuel metering valve, and tested under simulated engine operating conditions. The testing indicated that a digital effector with optical position feedback is a suitable candidate, with proper development for future digital electronic gas turbine controls. The testing also identified several problem areas which would have to be overcome in a final production configuration.

  1. An Adaptive Instability Suppression Controls Method for Aircraft Gas Turbine Engine Combustors

    NASA Technical Reports Server (NTRS)

    Kopasakis, George; DeLaat, John C.; Chang, Clarence T.

    2008-01-01

    An adaptive controls method for instability suppression in gas turbine engine combustors has been developed and successfully tested with a realistic aircraft engine combustor rig. This testing was part of a program that demonstrated, for the first time, successful active combustor instability control in an aircraft gas turbine engine-like environment. The controls method is called Adaptive Sliding Phasor Averaged Control. Testing of the control method has been conducted in an experimental rig with different configurations designed to simulate combustors with instabilities of about 530 and 315 Hz. Results demonstrate the effectiveness of this method in suppressing combustor instabilities. In addition, a dramatic improvement in suppression of the instability was achieved by focusing control on the second harmonic of the instability. This is believed to be due to a phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling. These results may have implications for future research in combustor instability control.

  2. IGR solid-state electrochemical NO sub x control for natural gas combustion exhaust gases

    SciTech Connect

    Hossain, M.S.; Neyman, M.; Cook, W.J. ); Gordon, A.Z. )

    1989-07-01

    Solid-state electrochemical technology, embodied in the IGR process, is used to reduce nitrogen oxides (NO{sub x}) to nitrogen and oxygen, and thereby control NO{sub x} emissions from natural gas powered engines. The IGR deNO{sub x} process is based on solid-state, flow-through, high surface area, porous oxygen ion conductive ceramic electrolytes. Recent bench-scale experiments have demonstrated NO{sub x} reduction in multicomponent gas streams, the inert portion of which simulate natural gas combustion products. The reduction products were analyzed by in situ gas chromatography to verify NO{sub x} reduction rates inferred from electrochemical measurements. IGR process advantages compared with existing NO{sub x} control technologies are reviewed.

  3. Effects of Aftermarket Control Technologies on Gas and ...

    EPA Pesticide Factsheets

    Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) with varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semi-volatile organic carbon (OC1) sub-fraction. In addition, results suggest that chemical composition, rather than PM size, is re

  4. Fish Oil Supplementation and Fatty Acid Synthase Expression in the Prostate: A Randomized Controlled Trial. Addendum

    DTIC Science & Technology

    2011-07-01

    acids ( PUFA ), particularly omega -3 fatty acids , inhibits SREBP-1 activation, resulting in a decreased transcription of FAS. 15. SUBJECT TERMS Prostate...Cancer; Lipid Metabolism; Clinical Trial; Omega -3 Fatty Acids 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES...controls, Menendez et al demonstrated that addition of omega -3 fatty acids (-3 FA), docosahexanoic acid (DHA), alpha- linolenic acid

  5. Determination of portal short-chain fatty acids in rats fed various dietary fibers by capillary gas chromatography.

    PubMed

    Murase, M; Kimura, Y; Nagata, Y

    1995-02-17

    A simple, rapid and sensitive capillary gas chromatographic method was investigated to measure portal short-chain fatty acids (SCFAs). A 20-microliters sample of portal plasma was denatured with sulfosalicylic acid and then extracted with diethyl ether before the removal of protein precipitate. The resultant extract was concentrated by a transfer to 50 microliters of 0.2 M NaOH, thus avoiding tedious further concentration steps. This reduced the sample volume to one-fourth. Since the ratio of acetic acid, a major SCFA, to other acids varies widely, ranging from 10-fold to 100-fold, acrylic and methacrylic acids were used as internal standards to simultaneously measure SCFAs having a carbon number of 2-6. As a result, good recovery (90.38-103.17%) and reproducibility (coefficient of variation 0.83-8.85%) were observed over a wide range. Furthermore, portal SCFAs in rats fed various dietary fibers were determined by the present method. We showed that the amounts not only of the major acids such as acetic acid and propionic acid, but also of the minor fermented products such as n-valeric acid and n-caproic acid, could be significantly changed by dietary manipulation. Thus, the present method is simple and reliable, and requires only a small amount of sample.

  6. Oxidative degradation of organic acids conjugated with sulfite oxidation in flue-gas desulfurization. Final report, June 1984-June 1986

    SciTech Connect

    Lee, Y.J.; Rochelle, G.T.

    1988-02-01

    This report gives results of a study of organic acid-degradation conjugated with sulfite oxidation under flue-gas desulfurization (FGD) conditions. The oxidative degradation constant, k12, is defined as the ratio of organic-acid degradation rate and sulfite oxidation-rate times the ratio of the concentrations of dissolved S(IV) and organic acid. It is not significantly affected by pH or dissolved oxygen in the absence of Mn or Fe. However, k12 is increased by certain transition metals such as Fe, Co, and Ni and is decreased by Mn and halides. Lower dissolved S(IV) magnifies these effects. A free-radical mechanism was proposed to describe the kinetics. 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), smaller dicarboxylic acids, monocarboxylic acids, other carbonyl compounds, and hydrocarbons.

  7. Oxidative degradation of organic acid conjugated with sulfite oxidation in flue gas desulfurization: products, kinetics and mechanism

    SciTech Connect

    Lee, Y.J.; Rochelle, G.T.

    1987-03-01

    Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (FGD) conditions. The oxidative degradation constant k/sub 12/ is defined as the ratio of organic acid degradation rate and sulfite oxidation rate times the ratio of the concentration of dissolved S(IV) and organic acid. It is not significantly affected by pH or dissolved oxygen in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Fe, Co, and Ni and is decreased by Mn and halides. Lower dissolved S(IV) magnifies these effects. A free radical mechanism was proposed to describe the kinetics. Hydroxy and sulfonated carboxylic acids degrade approximately 3 times slower than saturated dicarboxylic acids, while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude factor. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product - smaller dicarboxylic acids, monocarboxylic acids, other carbonyl compounds, and hydrocarbons. 30 references, 7 figures, 7 tables.

  8. 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.

  9. Glacial greenhouse-gas fluctuations controlled by ocean circulation changes.

    PubMed

    Schmittner, Andreas; Galbraith, Eric D

    2008-11-20

    Earth's climate and the concentrations of the atmospheric greenhouse gases carbon dioxide (CO(2)) and nitrous oxide (N(2)O) varied strongly on millennial timescales during past glacial periods. Large and rapid warming events in Greenland and the North Atlantic were followed by more gradual cooling, and are highly correlated with fluctuations of N(2)O as recorded in ice cores. Antarctic temperature variations, on the other hand, were smaller and more gradual, showed warming during the Greenland cold phase and cooling while the North Atlantic was warm, and were highly correlated with fluctuations in CO(2). Abrupt changes in the Atlantic meridional overturning circulation (AMOC) have often been invoked to explain the physical characteristics of these Dansgaard-Oeschger climate oscillations, but the mechanisms for the greenhouse-gas variations and their linkage to the AMOC have remained unclear. Here we present simulations with a coupled model of glacial climate and biogeochemical cycles, forced only with changes in the AMOC. The model simultaneously reproduces characteristic features of the Dansgaard-Oeschger temperature, as well as CO(2) and N(2)O fluctuations. Despite significant changes in the land carbon inventory, CO(2) variations on millennial timescales are dominated by slow changes in the deep ocean inventory of biologically sequestered carbon and are correlated with Antarctic temperature and Southern Ocean stratification. In contrast, N(2)O co-varies more rapidly with Greenland temperatures owing to fast adjustments of the thermocline oxygen budget. These results suggest that ocean circulation changes were the primary mechanism that drove glacial CO(2) and N(2)O fluctuations on millennial timescales.

  10. Multi-objective optimisation of wastewater treatment plant control to reduce greenhouse gas emissions.

    PubMed

    Sweetapple, Christine; Fu, Guangtao; Butler, David

    2014-05-15

    This study investigates the potential of control strategy optimisation for the reduction of operational greenhouse gas emissions from wastewater treatment in a cost-effective manner, and demonstrates that significant improvements can be realised. A multi-objective evolutionary algorithm, NSGA-II, is used to derive sets of Pareto optimal operational and control parameter values for an activated sludge wastewater treatment plant, with objectives including minimisation of greenhouse gas emissions, operational costs and effluent pollutant concentrations, subject to legislative compliance. Different problem formulations are explored, to identify the most effective approach to emissions reduction, and the sets of optimal solutions enable identification of trade-offs between conflicting objectives. It is found that multi-objective optimisation can facilitate a significant reduction in greenhouse gas emissions without the need for plant redesign or modification of the control strategy layout, but there are trade-offs to consider: most importantly, if operational costs are not to be increased, reduction of greenhouse gas emissions is likely to incur an increase in effluent ammonia and total nitrogen concentrations. Design of control strategies for a high effluent quality and low costs alone is likely to result in an inadvertent increase in greenhouse gas emissions, so it is of key importance that effects on emissions are considered in control strategy development and optimisation.

  11. 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.

  12. Mathematical method for the prediction of retention times of fatty acid methyl esters in temperature-programmed capillary gas chromatography.

    PubMed

    Torres, Alexandre G; Trugo, Nádia M F; Trugo, Luiz C

    2002-07-17

    An accurate method for identification of fatty acids in complex mixtures analyzed by temperature-programmed capillary gas chromatography is described. The method is based on a mathematical approach using regression curves obtained by plotting the relative retention times of fatty acid methyl esters (FAMEs) analyzed in isothermal and gradient temperature conditions. The method was applied to a complex biological sample (human milk), and it was possible to identify 64 fatty acids, including branched-chain and other fatty acids for which reference standards were not readily available. The identities of the majority of the peaks were confirmed by mass spectrometry. The relative residuals and the relative differences between estimated and measured relative retention times of individual FAMEs varied from 0.03 to 3.15% and from 0.0 to 2.9%, respectively. The method is useful for identification of fatty acids in routine analysis.

  13. Surfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tank

    NASA Astrophysics Data System (ADS)

    Pereira, R.; Schneider-Zapp, K.; Upstill-Goddard, R. C.

    2016-07-01

    Understanding the physical and biogeochemical controls of air-sea gas exchange is necessary for establishing biogeochemical models for predicting regional- and global-scale trace gas fluxes and feedbacks. To this end we report the results of experiments designed to constrain the effect of surfactants in the sea surface microlayer (SML) on the gas transfer velocity (kw; cm h-1), seasonally (2012-2013) along a 20 km coastal transect (North East UK). We measured total surfactant activity (SA), chromophoric dissolved organic matter (CDOM) and chlorophyll a (Chl a) in the SML and in sub-surface water (SSW) and we evaluated corresponding kw values using a custom-designed air-sea gas exchange tank. Temporal SA variability exceeded its spatial variability. Overall, SA varied 5-fold between all samples (0.08 to 0.38 mg L-1 T-X-100), being highest in the SML during summer. SML SA enrichment factors (EFs) relative to SSW were ˜ 1.0 to 1.9, except for two values (0.75; 0.89: February 2013). The range in corresponding k660 (kw for CO2 in seawater at 20 °C) was 6.8 to 22.0 cm h-1. The film factor R660 (the ratio of k660 for seawater to k660 for "clean", i.e. surfactant-free, laboratory water) was strongly correlated with SML SA (r ≥ 0.70, p ≤ 0.002, each n = 16). High SML SA typically corresponded to k660 suppressions ˜ 14 to 51 % relative to clean laboratory water, highlighting strong spatiotemporal gradients in gas exchange due to varying surfactant in these coastal waters. Such variability should be taken account of when evaluating marine trace gas sources and sinks. Total CDOM absorbance (250 to 450 nm), the CDOM spectral slope ratio (SR = S275 - 295/S350 - 400), the 250 : 365 nm CDOM absorption ratio (E2 : E3), and Chl a all indicated spatial and temporal signals in the quantity and composition of organic matter in the SML and SSW. This prompts us to hypothesise that spatiotemporal variation in R660 and its relationship with SA is a consequence of compositional

  14. Hormonal control of somatic embryo development from cultured cells of caraway: interactions of abscisic Acid, zeatin, and gibberellic Acid.

    PubMed

    Ammirato, P V

    1977-04-01

    The effects of abscisic acid, zeatin, and gibberellic acid on the development of somatic embryos from cultured cells of caraway (Carum carvi L.) were observed.Somatic embryos complete development on a basal medium without exogenous hormones, but some are subject to developmental abnormalities including malformed cotyledons and accessory embryos. Both zeatin and gibberellic acid, especially in combination, stimulate growth and increase the frequency of aberrant forms. Zeatin causes the formation of multiple shoots, leafy and abnormal cotyledons, and in the dark, enlarged hypocotyls; gibberellic acid effects root elongation, polycotyledony, and some callus formation. In contrast, abscisic acid, at concentrations which do not inhibit embryo maturation, selectively suppresses abnormal proliferations. With abscisic acid, and especially in the dark, a high percentage of embryos complete development with two fleshy cotyledons on unelongated axes free of accessory embryos.In the light, zeatin eliminates abscisic acid inhibition while gibberellic acid only partially counters its effect, promoting elongated radicles and green rather than white cotyledons. In the dark, zeatin in combination with abscisic acid stimulates extensive callusing. Gibberellic acid does not reverse the effects of abscisic acid but rather enhances them and can counter the disruptive effects of zeatin.The results demonstrate that the balance between abscisic acid on the one hand and zeatin and gibberellic acid on the other can effectively control somatic embryo development and either disrupt or ensure normal maturation.

  15. Going natural: Effective weed control in squash with pelargonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pelargonic acid, a natural, but not certified organic herbicide, has been shown to be phytotoxic, acting as a contact herbicide, injuring and killing plants through cell membrane disruption. Pelargonic acid, a fatty acid also known as nonanoic acid, is a nine-carbon chained organic compound found in...

  16. Nucleic Acid-Peptide Complex Phase Controlled by DNA Hybridization

    NASA Astrophysics Data System (ADS)

    Vieregg, Jeffrey; Lueckheide, Michael; Leon, Lorraine; Marciel, Amanda; Tirrell, Matthew

    When polyanions and polycations are mixed, counterion release drives formation of polymer-rich complexes that can either be solid (precipitates) or liquid (coacervates) depending on the properties of the polyelectrolytes. These complexes are important in many fields, from encapsulation of industrial polymers to membrane-free segregation of biomolecules such as nucleic acids and proteins. Condensation of long double-stranded DNA has been studied for several decades, but comparatively little attention has been paid to the polyelectrolyte behavior of oligonucleotides. We report here studies of DNA oligonucleotides (10 - 88 nt) complexed with polylysine (10 - 100 aa). Unexpectedly, we find that the phase of the resulting complexes is controlled by the hybridization state of the nucleic acid, with double-stranded DNA forming precipitates and single-stranded DNA forming coacervates. Stability increases with polyelectrolyte length and decreases with solution salt concentration, with complexes of the longer double-stranded polymers undergoing precipitate/coacervate/soluble transitions as ionic strength is increased. Mixing coacervates formed by complementary single-stranded oligonucleotides results in precipitate formation, raising the possibility of stimulus-responsive material design.

  17. Magnetically controlled deposition of metals using gas plasma. Final report

    SciTech Connect

    1998-04-02

    This is the first phase of a project that has the objective to develop a method of spraying materials on a substrate in a controlled manner to eliminate the waste and hazardous material generation inherent in present plating processes. The project is considering plasma spraying of metal on a substrate using magneto-hydrodynamics to control the plasma/metal stream. The process being developed is considering the use of commercially available plasma torches to generate the plasma/metal stream. The plasma stream is collimated, and directed using magnetic forces to the extent required for precise control of the deposition material. The project will be completed in phases. Phase one of the project, the subject of this grant, is the development of an analytical model that can be used to determine the feasibility of the process and to design a laboratory scale demonstration unit. The contracted time is complete, and the research is still continuing. This report provides the results obtained to date. As the model and calculations are completed those results will also be provided. This report contains the results of the computer code that have been completed to date. Results from a ASMEE Benchmark problem, flow over a backward step with heat transfer, Couette flow with magnetic forces, free jet flow are presented along with several other check calculations that are representative of the cases that were calculated in the course of the development process. The final cases that define a velocity field in the exit of a plasma spray torch with and without a magnetic field are in process. A separate program (SPRAY) has been developed that can track the plating material to the substrate and describe the distribution of the material on the substrate. When the jet calculations are complete SPRAY will be used to compare the distribution of material on the substrate with and without the effect of the magnetic focus.

  18. The control of Varroa destructor using oxalic acid.

    PubMed

    Gregorc, Ales; Planinc, I

    2002-05-01

    Twenty-four honeybee (Apis mellifera) colonies were used to monitor the efficacy of a solution of 2.9% oxalic acid (OA) and 31.9% sugar against the mite Varroa destructor. Mite mortality was established prior to and after OA treatments, which were conducted in August and September. The treatments resulted in 37% mite mortality as opposed to 1.11% in the controls. OA treatment conducted in September on previously untreated colonies resulted in 25% mite mortality. OA treatments in October and November resulted in approximately 97% mite mortality. These results suggest that OA is effective during the broodless period and less effective when applied to colonies with capped broods. The possible use of OA against the Varroa mite in honeybee colonies as an alternative to routine chemical treatments is discussed.

  19. 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.

  20. The Effect of Exogenous Abscisic Acid on Stomatal Development, Stomatal Mechanics, and Leaf Gas Exchange in Tradescantia virginiana

    PubMed Central

    Franks, Peter J.; Farquhar, Graham D.

    2001-01-01

    Gas exchange parameters and stomatal physical properties were measured in Tradescantia virginiana plants grown under well-watered conditions and treated daily with either distilled water (control) or 3.0 mm abscisic acid (ABA). Photosynthetic capacity (CO2 assimilation rate for any given leaf intercellular CO2 concentration [ci]) and relative stomatal sensitivity to leaf-to-air vapor-pressure difference were unaffected by the ABA treatment. However, at an ambient CO2 concentration (ca) of 350 μmol mol−1, ABA-treated plants operated with significantly lower ci. ABA-treated plants had significantly smaller stomata and higher stomatal density in their lower epidermis. Stomatal aperture versus guard cell pressure (Pg) characteristics measured with a cell pressure probe showed that although the form of the relationship was similar in control and ABA-treated plants, stomata of ABA-treated plants exhibited more complete closure at Pg = 0 MPa and less than half the aperture of stomata in control plants at any given Pg. Scaling from stomatal aperture versus Pg to stomatal conductance versus Pg showed that plants grown under ABA treatment would have had significantly lower maximum stomatal conductance and would have operated with lower stomatal conductance for any given guard cell turgor. This is consistent with the observation of lower ci/ca in ABA-treated plants with a ca of 350 μmol mol−1. It is proposed that the ABA-induced changes in stomatal mechanics and stomatal conductance versus Pg characteristics constitute an improvement in water-use efficiency that may be invoked under prolonged drought conditions. PMID:11161050

  1. OPTIMIZING TECHNOLOGY TO REDUCE MERCURY AND ACID GAS EMISSIONS FROM ELECTRIC POWER PLANTS

    SciTech Connect

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon

    2005-10-01

    Maps showing potential mercury, sulfur, chlorine, and moisture emissions for U.S. coal by county of origin were made from publicly available data (plates 1, 2, 3, and 4). Published equations that predict mercury capture by emission control technologies used at U.S. coal-fired utilities were applied to average coal quality values for 169 U.S. counties. The results were used to create five maps that show the influence of coal origin on mercury emissions from utility units with: (1) hot-side electrostatic precipitator (hESP), (2) cold-side electrostatic precipitator (cESP), (3) hot-side electrostatic precipitator with wet flue gas desulfurization (hESP/FGD), (4) cold-side electrostatic precipitator with wet flue gas desulfurization (cESP/FGD), and (5) spray-dry adsorption with fabric filter (SDA/FF) emission controls (plates 5, 6, 7, 8, and 9). Net (lower) coal heating values were calculated from measured coal Btu values, and estimated coal moisture and hydrogen values; the net heating values were used to derive mercury emission rates on an electric output basis (plate 10). Results indicate that selection of low-mercury coal is a good mercury control option for plants having hESP, cESP, or hESP/FGD emission controls. Chlorine content is more important for plants having cESP/FGD or SDA/FF controls; optimum mercury capture is indicated where chlorine is between 500 and 1000 ppm. Selection of low-sulfur coal should improve mercury capture where carbon in fly ash is used to reduce mercury emissions. Comparison of in-ground coal quality with the quality of commercially mined coal indicates that existing coal mining and coal washing practice results in a 25% reduction of mercury in U.S. coal before it is delivered to the power plant. Further pre-combustion mercury reductions may be possible, especially for coal from Texas, Ohio, parts of Pennsylvania and much of the western U.S.

  2. Identification and quantitation of urinary dicarboxylic acids as their dicyclohexyl esters in disease states by gas chromatography mass spectrometry.

    PubMed

    Norman, E J; Berry, H K; Denton, M D

    1979-12-01

    Clinical studies were conducted by gas chromatography mass spectrometry selected ion monitoring of urinary dicarboxylic acids as dicyclohexyl esters. The dicyclohexyl esters of the dicarboxylic acids give characteristic electron impact mass spectra suitable for selected ion monitoring. The mass spectra exhibit a prominent acid + 1H ion and an (acid + 1H)-H2O ion for use as quantitating and confirming ions. The cyclohexyl esters are stable for days at room temperature and have excellent chromatographic properties. Dicarboxylic acid quantitation is performed within one hour using only 50 microliter of unpurified urine. A rapid method specifically for methylmalonic acid quantitation is described which has assisted physicians in the diagnosis of pernicious anemia and methylmalonic aciduria. This procedure is applicable for screening urinary organic acids for detection of inborn errors of metabolism. The detection of a child with elevated medium length dicarboxylic acids in the terminal urine specimen is reported. This condition, previously described as an inborn error, is attributed to a terminal event. Finally, an increase in urinary succinic acid paralleling putrescine levels is described during a response to cancer chemotherapy.

  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. 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. 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.

  6. Uptake of gas phase nitrous acid onto boundary layer soil surfaces.

    PubMed

    Donaldson, Melissa A; Berke, Andrew E; Raff, Jonathan D

    2014-01-01

    Nitrous acid (HONO) is an important OH radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Large uncertainties remain in quantifying HONO sinks and determining the mechanism of HONO uptake onto surfaces. We report here the first laboratory determination of HONO uptake coefficients onto actual soil under atmospheric conditions using a coated-wall flow tube coupled to a highly sensitive chemical ionization mass spectrometer (CIMS). Uptake coefficients for HONO decrease with increasing RH from (2.5 ± 0.4) × 10(-4) at 0% RH to (1.1 ± 0.4) × 10(-5) at 80% RH. A kinetics model of competitive adsorption of HONO and water onto the particle surfaces fits the dependence of the HONO uptake coefficients on the initial HONO concentration and relative humidity. However, a multiphase resistor model based on the physical and chemical processes affecting HONO uptake is more flexible as it accounts for the pH dependence of HONO uptake and bulk diffusion in the soil matrix. Fourier transform infrared (FTIR) spectrometry and cavity-enhanced absorption spectroscopy (CEAS) studies indicate that NO and N2O (16% and 13% yield, respectively) rather than NO2 are the predominant gas phase products, while NO2(-) and NO3(-) were detected on the surface post-exposure. Results are compared to uptake coefficients inferred from models and field measurements, and the atmospheric implications are discussed.

  7. 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).

  8. 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

  9. 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.

  10. 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%.

  11. Development of the Next Generation Gas Trap for the Space Station Internal Thermal Control System

    NASA Technical Reports Server (NTRS)

    Leimkuehler, Thomas O.; Spelbring, Chris; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Design goals are to meet or exceed the current requirements to (1) include greater operating ranges and conditions, (2) eliminate reliance on the current hydrophilic tube fabrication process, and (3) increase operational life and tolerance to particulate and microbial growth fouling. In addition, the next generation gas trap will essentially be a 'dropin" design such that no modifications to the ITCS pump package assembly (PPA) will be required, and the implementation of the new design will not affect changes to the ITCS operational conditions, interfaces, or software. This paper will present the initial membrane module design and development work which has included (1) a trade study among several conceptual designs, (2) performance modeling of a hydrophobic-only design, and (3) small-scale development test data for the hydrophobic-only design. Testing has shown that the hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal.

  12. Model predictive control of a wet limestone flue gas desulfurization pilot plant

    SciTech Connect

    Perales, A.L.V.; Ollero, P.; Ortiz, F.J.G.; Gomez-Barea, A.

    2009-06-15

    A model predictive control (MPC) strategy based on a dynamic matrix (DMC) is designed and applied to a wet limestone flue gas desulfurization (WLFGD) pilot plant to evaluate what enhancement in control performance can be achieved with respect to a conventional decentralized feedback control strategy. The results reveal that MPC can significantly improve both reference tracking and disturbance rejection. For disturbance rejection, the main control objective in WLFGD plants, selection of tuning parameters and sample time, is of paramount importance due to the fast effect of the main disturbance (inlet SO{sub 2} load to the absorber) on the most important controlled variable (outlet flue gas SO{sub 2} concentration). The proposed MPC strategy can be easily applied to full-scale WLFGD plants.

  13. Photoswitchable fatty acids enable optical control of TRPV1

    PubMed Central

    Frank, James Allen; Moroni, Mirko; Moshourab, Rabih; Sumser, Martin; Lewin, Gary R.; Trauner, Dirk

    2015-01-01

    Fatty acids (FAs) are not only essential components of cellular energy storage and structure, but play crucial roles in signalling. Here we present a toolkit of photoswitchable FA analogues (FAAzos) that incorporate an azobenzene photoswitch along the FA chain. By modifying the FAAzos to resemble capsaicin, we prepare a series of photolipids targeting the Vanilloid Receptor 1 (TRPV1), a non-selective cation channel known for its role in nociception. Several azo-capsaicin derivatives (AzCAs) emerge as photoswitchable agonists of TRPV1 that are relatively inactive in the dark and become active on irradiation with ultraviolet-A light. This effect can be rapidly reversed by irradiation with blue light and permits the robust optical control of dorsal root ganglion neurons and C-fibre nociceptors with precision timing and kinetics not available with any other technique. More generally, we expect that photolipids will find many applications in controlling biological pathways that rely on protein–lipid interactions. PMID:25997690

  14. Research on coal-mine gas monitoring system controlled by annealing simulating algorithm

    NASA Astrophysics Data System (ADS)

    Zhou, Mengran; Li, Zhenbi

    2007-12-01

    This paper introduces the principle and schematic diagram of gas monitoring system by means of infrared method. Annealing simulating algorithm is adopted to find the whole optimum solution and the Metroplis criterion is used to make iterative algorithm combination optimization by control parameter decreasing aiming at solving large-scale combination optimization problem. Experiment result obtained by the performing scheme of realizing algorithm training and flow of realizing algorithm training indicates that annealing simulating algorithm applied to identify gas is better than traditional linear local search method. It makes the algorithm iterate to the optimum value rapidly so that the quality of the solution is improved efficiently. The CPU time is shortened and the identifying rate of gas is increased. For the mines with much-gas gushing fatalness the regional danger and disaster advanced forecast can be realized. The reliability of coal-mine safety is improved.

  15. Financial and environmental costs of manual versus automated control of end-tidal gas concentrations.

    PubMed

    Tay, S; Weinberg, L; Peyton, P; Story, D; Briedis, J

    2013-01-01

    Emerging technologies that reduce the economic and environmental costs of anaesthesia have had limited assessment. We hypothesised that automated control of end-tidal gases, a new feature in anaesthesia machines, will consistently reduce volatile agent consumption cost and greenhouse gas emissions. As part of the planned replacement of anaesthesia machines in a tertiary hospital, we performed a prospective before and after study comparing the cost and greenhouse gas emissions of isoflurane, sevoflurane and desflurane when using manual versus automated control of end-tidal gases. We analysed 3675 general anaesthesia cases with inhalational agents: 1865 using manual control and 1810 using automated control. Volatile agent cost was $18.87/hour using manual control and $13.82/hour using automated control: mean decrease $5.05/hour (95% confidence interval: $0.88-9.22/hour, P=0.0243). The 100-year global warming potential decreased from 23.2 kg/hour of carbon dioxide equivalents to 13.0 kg/hour: mean decrease 10.2 kg/hour (95% confidence interval: 2.7-17.7 kg/hour, P=0.0179). Automated control reduced costs by 27%. Greenhouse gas emissions decreased by 44%, a greater than expected decrease facilitated by a proportional reduction in desflurane use. Automated control of end-tidal gases increases participation in low flow anaesthesia with economic and environmental benefits.

  16. Tailored fatty acid synthesis via dynamic control of fatty acid elongation

    SciTech Connect

    Torella, JP; Ford, TJ; Kim, SN; Chen, AM; Way, JC; Silver, PA

    2013-07-09

    Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even-and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitation, we programmed an essential ketoacyl synthase to degrade in response to a chemical inducer, thereby slowing acyl-ACP elongation and redirecting flux from phospholipid synthesis to MCFA production. Our results show that induced protein degradation can be used to dynamically alter metabolic flux, and thereby increase the yield of a desired compound. The strategy reported herein should be widely useful in a range of metabolic engineering applications in which essential enzymes divert flux away from a desired product, as well as in the production of polyketides, bioplastics, and other recursively synthesized hydrocarbons for which chain-length control is desired.

  17. Factors affecting variations in the detailed fatty acid profile of Mediterranean buffalo milk determined by 2-dimensional gas chromatography.

    PubMed

    Pegolo, S; Stocco, G; Mele, M; Schiavon, S; Bittante, G; Cecchinato, A

    2017-04-01

    Buffalo milk is the world's second most widely produced milk, and increasing attention is being paid to its composition, particularly the fatty acid profile. The objectives of the present study were (1) to characterize the fatty acid composition of Mediterranean buffalo milk, and (2) to investigate potential sources of variation in the buffalo milk fatty acid profile. We determined the profile of 69 fatty acid traits in 272 individual samples of Mediterranean buffalo milk using gas chromatography. In total, 51 individual fatty acids were identified: 24 saturated fatty acids, 13 monounsaturated fatty acids, and 14 polyunsaturated fatty acids. The major individual fatty acids in buffalo milk were in the order 16:0, 18:1 cis-9, 14:0, and 18:0. Saturated fatty acids were the predominant fraction in buffalo milk fat (70.49%); monounsaturated and polyunsaturated fatty acids were at 25.95 and 3.54%, respectively. Adopting a classification based on carbon-chain length, we found that medium-chain fatty acids (11-16 carbons) represented the greater part (53.7%) of the fatty acid fraction of buffalo milk, whereas long-chain fatty acids (17-24 carbons) and short-chain fatty acids (4-10 carbons) accounted for 32.73 and 9.72%, respectively. The n-3 and n-6 fatty acids were 0.46 and 1.77%, respectively. The main conjugated linoleic acid, rumenic acid, represented 0.45% of total milk fatty acids. Herd/test date and stage of lactation were confirmed as important sources of variation in the fatty acid profile of buffalo milk. The percentages of short-chain and medium-chain fatty acids in buffalo milk increased in early lactation (+0.6 and +3.5%, respectively), whereas long-chain fatty acids decreased (-4.2%). The only exception to this pattern was butyric acid, which linearly decreased from the beginning of lactation, confirmation that its synthesis is independent of malonyl-CoA. These results seem to suggest that in early lactation the mobilization of energy reserves may have less

  18. Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus.

    PubMed

    Heinrich, Erica; Bradley, Timothy

    2014-08-01

    Insects display an array of respiratory behaviors, including the use of discontinuous gas exchange. This pattern is characterized by periods of spiracular closure, micro-openings (flutter), and complete openings during which the majority of gas exchange takes place. A current model of insect spiracular control suggests that spiracles are controlled by two interacting feedback loops, which produce the discontinuous pattern. The flutter period is thought to be initiated by a critically low partial pressure of oxygen, while the open period is initiated by a critically high CO2 threshold. The goal of our study was to test this control model under conditions of feeding-induced or temperature-induced changes in metabolic rate. We manipulated the metabolic rate of the insect Rhodnius prolixus using two discrete mechanisms: (1) feeding the insects a bloodmeal or (2) exposing them to a range of temperatures (18-38°C). Examining the variation in the gas exchange patterns produced by insects in each of these treatments allowed us to determine whether spiracular control is sensitive to metabolic rate and/or temperature. We found that increases in temperature caused significant decreases in open phase burst volumes and premature abandonment of discontinuous gas exchange cycles. These effects were not observed in fed individuals maintained at a single temperature despite their higher metabolic rates. Our results indicate that some part of the spiracular control mechanism is temperature sensitive, suggesting a possible role for pH in CO2 sensing.

  19. Compositions and method for controlling precipitation when acidizing sour wells

    SciTech Connect

    Dill, W.R.; Walker, M.L.

    1989-12-19

    This patent describes an acidizing composition for treating a sour well. It comprises: a base acid solution having an initial ph below 1.9; an iron sequestering agent to combine with iron present in the solution comprising at least one compound selected from the group consisting of aminopolycarboxylic acids, hydroxycarboxylic acids, cyclic polyethers and derivatives of the acids and ethers present in an amount of from about 0.25 to about 5 percent by weight of the acid solution; and a sulfide modifier to combine with sulfides present in the solution comprising at least one member selected from the group consisting of an aldehyde, acetal, hemiacetal and any other compound capable of forming an aldehyde in solution, present in an amount of from about 1 to about 4 percent by weight of the acid solution, whereby precipitation of ferric hydroxide, ferrous sulfide and elemental sulfur is inhibited as acid spending occurs.

  20. 49 CFR 192.197 - Control of the pressure of gas delivered from high-pressure distribution systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Control of the pressure of gas delivered from high... STANDARDS Design of Pipeline Components § 192.197 Control of the pressure of gas delivered from high... external static or control lines. (b) If the maximum actual operating pressure of the distribution...

  1. Distribution and controls on gas hydrate in the ocean-floor environment

    SciTech Connect

    Dillon, W.P.

    1995-12-31

    Methane hydrate, a crystalline solid that is formed of water and gas molecules, is widespread in oceanic sediments. It occurs at water depths that exceed 300 to 500 m and in a zone that commonly extends from the sea floor, down several hundred meters - the base of the zone is limited by increased temperature. To determine factors that control gas hydrate concentration, we have mapped its distribution off the U.S. Atlantic coast using acoustic remote-sensing methods. Most natural gas hydrate is formed from biogenic methane, and therefore it is concentrated where there is a rapid accumulation of organic detritus and also where there is a rapid accumulation of sediments (which protect detritus from oxidation). When hydrate fills the pore space of sediment, it can reduce permeability and create a gas trap. Such trapping of gas beneath hydrate may cause the formation of the most concentrated hydrate deposits, perhaps because the gas that is held in the trap can slowly diffuse upwards or migrate through faults. Hydrate-sealed traps are formed by hills on the sea floor, by dipping strata, or by salt(?) domes. Off the southeastern United States, a small area (only 3000 km{sup 2}) beneath a ridge formed by rapidly-deposited sediments appears to contain a volume of methane in hydrate that is equivalent to {approximately}30 times the U.S. annual consumption of gas. The breakdown of hydrate can cause submarine landslides by converting the hydrate to gas plus water and generating a rise of pore pressure. Conversely, sea-floor landslides can cause breakdown of hydrate by reducing the pressure in sediments. These interacting processes may cause cascading slides, which would result in breakdown of hydrate and release of methane to the atmosphere. This addition of methane to the global greenhouse would significantly influence climate. Gas hydrate in sea-floor sediments is potentially significant to climate, energy resources, and sea-floor stability.

  2. Inherently antioxidant and antimicrobial tannic acid release from poly(tannic acid) nanoparticles with controllable degradability.

    PubMed

    Sahiner, Nurettin; Sagbas, Selin; Aktas, Nahit; Silan, Coskun

    2016-06-01

    From a natural polyphenol, Tannic acid (TA), poly(TA) nanoparticles were readily prepared using a single step approach with three different biocompatible crosslinkers; trimethylolpropane triglycidyl ether (TMPGDE), poly(ethylene glycol) diglycidyl ether (PEGGE), and trisodium trimetaphosphate (STMP). P(TA) particles were obtained with controllable diameters between 400 to 800nm with -25mV surface charge. The effect of synthesis conditions, such as the emulsion medium, pH values of TA solution, and the type of crosslinker, on the shape, size, dispersity, yield, and degradability of poly(Tannic Acid) (p(TA)) nanoparticles was systematically investigated. The hydrolytic degradation amount in physiological pH conditions of 5.4, 7.4, and 9.0 at 37.5°C were found to be in the order TMPGDEcontrolled by the appropriate choice of crosslinker, and the pH of releasing media. The highest TA release, 600mg/g, was obtained for TMPGDE-crosslinked p(TA) particles in intestinal pH conditions (pH 9) over 3 days; whereas, a slow and linear TA release profile over almost 30 days was obtained by using PEGGE-crosslinked p(TA) in body fluid pH conditions (pH 7.4). The total phenol content of p(TA) particles was calculated as 70±1μgmL(-1) for 170μgmL(-1) p(TA), and the trolox equivalent antioxidant capacity was found to be 2027±104mM trolox equivalent g(-1). Moreover, p(TA) nanoparticles demonstrated strong antimicrobial effects against common bacterial strains. More interestingly, with a higher concentration of p(TA) particles, higher blood clotting indices were obtained.

  3. Investigation of liquid and gas chromatography techniques for separation of diastereomers of beta-(alpha-methylbenzyl) amino isobutyric acid.

    PubMed

    Held, Charles B; Robbins, David K

    2003-09-01

    Cryptophycins are macrolides investigated as potential anticancer agents. These large cyclic molecules are generated via a convergent process, utilizing the coupling of several smaller fragments synthesized individually. During early synthetic development of the beta-amino acid fragment C, analytical methods are necessary for the characterization of products resulting from the various routes being studied. One route being evaluated produces (RR) and (RS) diastereomers of beta-(alpha-methylbenzyl) amino isobutyric acid as intermediates. To measure diastereomeric excess (%de), assay conditions using high-performance liquid chromatography (HPLC) and capillary gas chromatographic (GC) techniques are explored. Derivatization methods using trifluoroacetyl- and silyl-derivatives are investigated for use with capillary GC. The results of the GC investigations are found to be only partially successful. Ion-pair HPLC is determined to be the optimal technique, utilizing pentanesulfonic acid as the counter ion to the amine group of beta-(alpha-methylbenzyl) amino isobutyric acid.

  4. Comparison between high-performance liquid chromatography and gas chromatography methods for fatty acid identification and quantification in potato crisps.

    PubMed

    Sanches-Silva, A; Rodríguez-Bernaldo de Quirós, A; López-Hernández, J; Paseiro-Losada, P

    2004-04-02

    A reversed-phase high performance liquid chromatographic (RP-HLPC) method was compared with a gas chromatography-flame ionization detection (GC-FID) method for determining fatty acids in potato crisps. Different extraction procedures were used. Fatty acids were quantified by linear regression. Both methods presented good precision (R.S.D. < or = 5.88%) and recovery (> or = 82.31%). The precision using HPLC method was slightly better than for GC-FID method. There was good agreement between the fatty acid composition of potato crisps analysed by both methods. For most purposes the HPLC method would be better. However, when more fatty acids need to be analysed, GC is a more suitable method.

  5. The use of gas chromatography to analyze compositional changes of fatty acids in rat liver tissue during pregnancy.

    PubMed

    Fisk, Helena L; West, Annette L; Childs, Caroline E; Burdge, Graham C; Calder, Philip C

    2014-03-13

    Gas chromatography (GC) is a highly sensitive method used to identify and quantify the fatty acid content of lipids from tissues, cells, and plasma/serum, yielding results with high accuracy and high reproducibility. In metabolic and nutrition studies GC allows assessment of changes in fatty acid concentrations following interventions or during changes in physiological state such as pregnancy. Solid phase extraction (SPE) using aminopropyl silica cartridges allows separation of the major lipid classes including triacylglycerols, different phospholipids, and cholesteryl esters (CE). GC combined with SPE was used to analyze the changes in fatty acid composition of the CE fraction in the livers of virgin and pregnant rats that had been fed various high and low fat diets. There are significant diet/pregnancy interaction effects upon the omega-3 and omega-6 fatty acid content of liver CE, indicating that pregnant females have a different response to dietary manipulation than is seen among virgin females.

  6. Mead acid (20:3n-9) and n-3 polyunsaturated fatty acids are not associated with risk of posterior longitudinal ligament ossification: results of a case-control study.

    PubMed

    Hamazaki, Kei; Kawaguchi, Yoshiharu; Nakano, Masato; Yasuda, Taketoshi; Seki, Shoji; Hori, Takeshi; Hamazaki, Tomohito; Kimura, Tomoatsu

    2015-05-01

    Ossification of the posterior longitudinal ligament (OPLL) involves the replacement of ligamentous tissue with ectopic bone. Although genetics and heritability appear to be involved in the development of OPLL, its pathogenesis remains to be elucidated. Given previous findings that 5,8,11-eicosatrienoic acid [20:3n-9, Mead acid (MA)] has depressive effects on osteoblastic activity and anti-angiogenic effects, and that n-3 polyunsaturated fatty acids (PUFAs) have a preventive effect on heterotopic ossification, we hypothesized that both fatty acids would be involved in OPLL development. To examine the biological significance of these and other fatty acids in OPLL, we conducted this case-control study involving 106 patients with cervical OPLL and 109 age matched controls. Fatty acid composition was determined from plasma samples by gas chromatography. Associations between fatty acid levels and incident OPLL were evaluated by logistic regression. Contrary to our expectations, we found no significant differences between patients and controls in the levels of MA or n-3 PUFAs (e.g., eicosapentaenoic acid and docosahexaenoic acid). Logistic regression analysis did not reveal any associations with OPLL risk for MA or n-3 PUFAs. In conclusion, no potential role was found for MA or n-3 PUFAs in ectopic bone formation in the spinal canal.

  7. Three-Dimensional Model for Electrospinning Processes in Controlled Gas Counterflow

    PubMed Central

    2016-01-01

    We study the effects of a controlled gas flow on the dynamics of electrified jets in the electrospinning process. The main idea is to model the air drag effects of the gas flow by using a nonlinear Langevin-like approach. The model is employed to investigate the dynamics of electrified polymer jets at different conditions of air drag force, showing that a controlled gas counterflow can lead to a decrease of the average diameter of electrospun fibers, and potentially to an improvement of the quality of electrospun products. We probe the influence of air drag effects on the bending instabilities of the jet and on its angular fluctuations during the process. The insights provided by this study might prove useful for the design of future electrospinning experiments and polymer nanofiber materials. PMID:26859532

  8. Generating Apparatus for Gas Heat Pump System using Sensorless-Controlled Permanent Magnet Synchronous Generator

    NASA Astrophysics Data System (ADS)

    Toba, Akio; Fujita, Kouetsu; Maeda, Toshihiro; Kato, Tomohiko

    A unique generating system for Gas heat pump system (GHP) is presented. The GHP is an air-conditioning system, in which the compressors are driven by a gas engine. The proposed system is applied to the outside unit of GHP to feed the electrical equipments inside. The system utilizes a permanent magnet synchronous generator, which is connected to the gas engine, to realize high-efficiency and small-size. The generator is controlled by a converter with sensorless control technology to eliminate the position sensor. Another major topic is the “free-run startup" technique to start the converter when the generator is rotating. The system configuration and principles of the techniques are set forth, followed by experimental results which show that the system works properly and successfully.

  9. Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

    PubMed

    Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

    2016-09-08

    Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd.

  10. Three-Dimensional Model for Electrospinning Processes in Controlled Gas Counterflow.

    PubMed

    Lauricella, Marco; Pisignano, Dario; Succi, Sauro

    2016-07-14

    We study the effects of a controlled gas flow on the dynamics of electrified jets in the electrospinning process. The main idea is to model the air drag effects of the gas flow by using a nonlinear Langevin-like approach. The model is employed to investigate the dynamics of electrified polymer jets at different conditions of air drag force, showing that a controlled gas counterflow can lead to a decrease of the average diameter of electrospun fibers, and potentially to an improvement of the quality of electrospun products. We probe the influence of air drag effects on the bending instabilities of the jet and on its angular fluctuations during the process. The insights provided by this study might prove useful for the design of future electrospinning experiments and polymer nanofiber materials.

  11. Rapid quantification of urinary 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid using fast gas chromatography-mass spectrometry.

    PubMed

    Jamerson, Matthew H; Welton, Robert M; Morris-Kukoski, Cynthia L; Klette, Kevin L

    2005-10-01

    Human urine specimens that were determined to be presumptively positive for metabolites of delta9-tetrahydrocannabinol by immunoassay screening were assayed using a novel fast gas chromatography-mass spectrometry (FGC-MS) analytical method to determine whether this method would improve the efficiency of specimen processing without diminishing the reliability of metabolite identification and quantification. Urine specimens were spiked with deuterated internal standard, subjected to solid-phase extraction, and derivatized using tetramethylammonium hydroxide and iodomethane. The methyl ester/methyl ether derivatives were identified and quantified using both a traditional GC-MS method and the newly developed FGC-MS method. The FGC-MS method was demonstrated to be linear between 3.8 and 1500 ng/mL 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (11-nor-delta-THC-COOH). The intrarun precision of 15 replicates of a 15 ng/mL control and the interrun precision of 161 sets of 7, 15, and 60 ng/mL controls were acceptable (coefficients of variation < 5.5%). The FGC-MS method was demonstrated to be specific for identifying 11-nor-delta9-THC-COOH and none of 43 tested substances interfered with identification and quantification of 11-nor-delta9-THC-COOH. Excellent data concordance (R2 > 0.993) was found for two specimen sets assayed using both methods. The FGC-MS method, when compared with a traditional GC-MS method, reduces total assay time by approximately 40% with no decrease in data quality.

  12. 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.

  13. Genetic mapping of QTLs controlling fatty acids provided insights into the genetic control of fatty acid synthesis pathway in peanut (Arachis hypogaea L.).

    PubMed

    Wang, Ming Li; Khera, Pawan; Pandey, Manish K; Wang, Hui; Qiao, Lixian; Feng, Suping; Tonnis, Brandon; Barkley, Noelle A; Pinnow, David; Holbrook, Corley C; Culbreath, Albert K; Varshney, Rajeev K; Guo, Baozhu

    2015-01-01

    Peanut, a high-oil crop with about 50% oil content, is either crushed for oil or used as edible products. Fatty acid composition determines the oil quality which has high relevance to consumer health, flavor, and shelf life of commercial products. In addition to the major fatty acids, oleic acid (C18:1) and linoleic acid (C18:2) accounting for about 80% of peanut oil, the six other fatty acids namely palmitic acid (C16:0), stearic acid (C18:0), arachidic acid (C20:0), gadoleic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0) are accounted for the rest 20%. To determine the genetic basis and to improve further understanding on effect of FAD2 genes on these fatty acids, two recombinant inbred line (RIL) populations namely S-population (high oleic line 'SunOleic 97R' × low oleic line 'NC94022') and T-population (normal oleic line 'Tifrunner' × low oleic line 'GT-C20') were developed. Genetic maps with 206 and 378 marker loci for the S- and the T-population, respectively were used for quantitative trait locus (QTL) analysis. As a result, a total of 164 main-effect (M-QTLs) and 27 epistatic (E-QTLs) QTLs associated with the minor fatty acids were identified with 0.16% to 40.56% phenotypic variation explained (PVE). Thirty four major QTLs (>10% of PVE) mapped on five linkage groups and 28 clusters containing more than three QTLs were also identified. These results suggest that the major QTLs with large additive effects would play an important role in controlling composition of these minor fatty acids in addition to the oleic and linoleic acids in peanut oil. The interrelationship among these fatty acids should be considered while breeding for improved peanut genotypes with good oil quality and desired fatty acid composition.

  14. Unified Measurement System with Suction Control for Gas Transport Parameters in Porous Media

    NASA Astrophysics Data System (ADS)

    Kawamoto, K.; Rouf, M. A.; Hamamoto, S.; Sakaki, T.; Komatsu, T.; Moldrup, P.

    2010-12-01

    Pore geometric parameters including pore size distribution, total and air-filled porosities, pore tortuosity and connectivity strongly influence air flow in porous media, and, thus, characterize gas transport parameters such as gas diffusion coefficient Dp and air permeability ka. In this study, the gas transport parameters were measured for porous media with varying textures under repeated drying and wetting cycles using a newly-developed measurement system, and the hysteretic behaviors in the gas transport parameters were examined. A unified measurement system with suction control (UMS_SC) was developed for measuring soil water characteristics curve and gas transport parameters sequentially under drying and wetting cycles. It consisted of a porous plate, diffusion chamber, sample ring (15 cm in inner diameter and 12 cm in height), tensiometer, soil moisture sensor, oxygen electrodes and air pressure gauges. Soil water characteristics curve and gas transport parameters (gas diffusion coefficient Dp and air permeability ka) for differently textured materials including sand, molten slag , and a mixture material of MS and volcanic ash soil were measured under repeated drying and wetting cycles. The measurement for each porous material was initiated from a full saturation and suction head was increased/decreased in steps in the drainage/wetting cycles. Moreover, independent measurements of Dp and ka were carried out for repacked air-dried samples using a cylindrical mold (15 cm in inner diameter and 12 cm in height) in order to obtain the Dp and ka values at a full dry condition. The newly-developed UMS_SC performed well for the applied suction head less than 50 cm of water with corresponding saturation of roughly 0.3-0.5. The gas transport parameters were well measured at each suction head level under repeated drying and wetting cycles, and the measured gas transport parameters including the independent measurements were verified by literature data as well as

  15. [Analysis of fatty acids in Gmnocypris przewalskii oil by gas chromatography/mass spectrometry with base-catalyzed transesterification].

    PubMed

    Bo, Haibo; Wang, Xia; Zhai, Zongde; Li, Yongmin; Chen, Liren

    2006-03-01

    The composition of fatty acids (FA) in Gymnocypris przewalskii oil was identified and quantified by gas chromatography (GC)/electron impact (EI) mass spectrometry (MS). A base-catalyzed transesterification method was used to convert fatty acids to methyl esters. The lipids were extracted using petroleum ether and the total lipids in dried meat and skin of Gymnocypris przewalskii were about 25%. Forty-seven fatty acids were identified in the current study. Main types of fatty acids found in the oils were normal saturated, mono-branched, multi-branched, cyclopropane, furanoid, normal monounsaturated and polyunsaturated fatty acids. Saturated fatty acids were approximately 25. 7% of the total, and the main components were C(14:0) (3.4%), C(16:0) (19.4%) and C(18:0) (1.1%). Unsaturated fatty acids were totally 73.6%, and the major components of monounsaturated fatty acids were C(16:1 (9)) (19.8%), C(18:1) (9)) (18. 6%) and C(18:1 (11)) (7.3%); polyunsaturated fatty acids were mainly composed of C(18:2 (9,12)) (4.8%), C(18:3 (9, 12, 15)) (3.1%), C(20:4 (5, 8, 1, 14)) (1.2%), C(20:5 (5, 8, 11, 14, 17)) (EPA, 9.4%) and C(22:6 (4, 7, 10, 13, 16, 19)) (DHA, 6.7%). Especially, furyl-, cyclopropane- and several odd and branched chain fatty acids were found in Gymnocypris przewalskii oil. It is thus an important dietary resource of functional fatty acids.

  16. FIELD TEST MEASUREMENTS AT FIVE MUNICIPAL SOLID WASTE LANDFILLS WITH LANDFILL GAS CONTROL TECHNOLOGY--FINAL REPORT

    EPA Science Inventory

    Research was conducted to evaluate landfill gas emissions at five municipal solid waste landfills which have modern control technology for landfill gas emissions. Comprehensive testing was conducted on the raw landfill gas and the combustion outlet exhaust. The project had two ...

  17. Adipic acid enhanced flue gas desulfurization process for industrial boilers: Volume 1. Field test results. Project summary

    SciTech Connect

    Clarke, P.A.; Gerstle, R.W.; Henzel, D.S.; Mason, K.W.; Sabatini, S.R.

    1983-03-01

    Test results show that adding adipic acid to the limestone slurry significantly improved the SO/sub 2/ removal efficiency of the FGD system. Limited baseline data on operations with limestone only indicated a performance level of 55% SO/sub 2/ removal. Adding about 2200 ppM of adipic acid to the limestone scrubbing systems, the unit's level of performance increased to an average of 94.3% SO/sub 2/ removal which was maintained within a standard deviation of 2.2% over a 30-day test period during which boiler load was 70 to 130 million Btu/hr and gas throughput varied 300%.

  18. [Study of the fatty acid components of the triglyceride fraction of the blood in normal and thalassemic subjects, using gas chromatography].

    PubMed

    Gilli, G; Moiraghi Ruggenini, A; Nani, E; Bottura, G; Mastretta, L

    1977-01-01

    Thin layer chromatography was used to separate the triglyceridic fraction of plasma lipides in normal (19) and thalassaemic (15) subjects. Gas chromatographic analysis of the fraction was then carried out and the fatty acids represented were identified qualitatively and quantitatively. Statistically significant variations, specifically increase in arachidonic acid and reduction in palmitic and linoleic acids, were observed in the thalassaemic patients.

  19. Genetic and environmental relationships of detailed milk fatty acids profile determined by gas chromatography in Brown Swiss cows.

    PubMed

    Pegolo, S; Cecchinato, A; Casellas, J; Conte, G; Mele, M; Schiavon, S; Bittante, G

    2016-02-01

    The aim of this study was to characterize the profile of 47 fatty acids, including conjugated linoleic acid (CLA), 13 fatty acid groups, and 5 Δ(9)-desaturation indices in milk samples from Brown Swiss cows. The genetic variation was assessed and the statistical relevance of the genetic background for each trait was evaluated using the Bayes factor test. The additive genetic, herd-date, and residual relationships were also estimated among all single fatty acids and groups of fatty acids. Individual milk samples were collected from 1,158 Italian Brown Swiss cows and a detailed analysis of fat percentages and milk fatty acid compositions was performed by gas chromatography. Bayesian animal models were used for (co)variance components estimation. Exploitable genetic variation was observed for most of the de novo synthesized fatty acids and saturated fatty acids, except for C4:0 and C6:0, whereas long-chain fatty acids and unsaturated fatty acids (including CLA) were mainly influenced by herd-date effects. Herd-date effect explained large portions of the total phenotypic variance for C18:2 cis-9,cis-12 (0.668), C18:3 cis-9,cis-12,cis-15 (0.631), and the biohydrogenation and elongation products of these fatty acids. The desaturation ratios showed higher heritability estimates than the individual fatty acids, except for CLA desaturation index (0.098). Among the medium-chain fatty acids, C12:0 had greater heritability than C14:0 (0.243 vs. 0.097, respectively). Both C14:0 and C16:0 showed negative additive genetic correlations with the main monounsaturated and polyunsaturated fatty acids of milk fat, suggesting that their synthesis in the mammary gland may be influenced by the presence of unsaturated fatty acids. No correlation was observed between C4:0 and the other short-chain fatty acids (except for C6:0), confirming the independence of C4:0 from de novo mammary fatty acid synthesis. Among the genetic correlations dealing with potentially beneficial fatty acids, C18

  20. Compositions and method for controlling precipitation when acidizing sour wells

    SciTech Connect

    Dill, W.R.; Walker, M.L.

    1990-08-21

    This patent describes a method of treating a sour well penetrating a subterranean formation. It comprises: introducing into the well a treating fluid comprising an acid solution having a pH below 1.9, an iron sequestering agent comprising at least one compound selected from the group consisting of aminopolycarboxylic acids, hydroxycarboxylic acids, cyclic polyethers and derivatives of the acids and ethers, present in an amount of from about 0.25 to about 5 percent by weight of the acid solution, and a sulfide modifier comprising at least one compound selected from the group consisting of an aldehyde, acetal, hemiacetal and any other compound capable of forming aldehydes in the acid solution, present in an amount of from about 0.25 to about 5 percent of the acid solution; and treating the subterranean formation with the treating fluid.

  1. A Plan for Revolutionary Change in Gas Turbine Engine Control System Architecture

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.

    2011-01-01

    The implementation of Distributed Engine Control technology on the gas turbine engine has been a vexing challenge for the controls community. A successful implementation requires the resolution of multiple technical issues in areas such as network communications, power distribution, and system integration, but especially in the area of high temperature electronics. Impeding the achievement has been the lack of a clearly articulated message about the importance of the distributed control technology to future turbine engine system goals and objectives. To resolve these issues and bring the technology to fruition has, and will continue to require, a broad coalition of resources from government, industry, and academia. This presentation will describe the broad challenges facing the next generation of advanced control systems and the plan which is being put into action to successfully implement the technology on the next generation of gas turbine engine systems.

  2. Active bypass flow control for a seal in a gas turbine engine

    DOEpatents

    Ebert, Todd A.; Kimmel, Keith D.

    2017-03-14

    An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears In at least one embodiment, the metering device may include an annular ring having at least one metering orifice extending therethrough, whereby alignment of the metering orifice with the outlet may be adjustable to change a cross-sectional area of an opening of aligned portions of the outlet and the metering orifice.

  3. Active bypass flow control for a seal in a gas turbine engine

    DOEpatents

    Ebert, Todd A.; Kimmel, Keith D.

    2017-01-10

    An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears. In at least one embodiment, the metering device may include a valve formed from one or more pins movable between open and closed positions in which the one pin at least partially bisects the bypass channel to regulate flow.

  4. Geologic controls on gas hydrate occurrence in the Mount Elbert prospect, Alaska North Slope

    USGS Publications Warehouse

    Boswell, R.; Rose, K.; Collett, T.S.; Lee, M.; Winters, W.; Lewis, K.A.; Agena, W.

    2011-01-01

    Data acquired at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well, drilled in the Milne Point area of the Alaska North Slope in February, 2007, indicates two zones of high gas hydrate saturation within the Eocene Sagavanirktok Formation. Gas hydrate is observed in two separate sand reservoirs (the D and C units), in the stratigraphically highest portions of those sands, and is not detected in non-sand lithologies. In the younger D unit, gas hydrate appears to fill much of the available reservoir space at the top of the unit. The degree of vertical fill with the D unit is closely related to the unit reservoir quality. A thick, low-permeability clay-dominated unit serves as an upper seal, whereas a subtle transition to more clay-rich, and interbedded sand, silt, and clay units is associated with the base of gas hydrate occurrence. In the underlying C unit, the reservoir is similarly capped by a clay-dominated section, with gas hydrate filling the relatively lower-quality sands at the top of the unit leaving an underlying thick section of high-reservoir quality sands devoid of gas hydrate. Evaluation of well log, core, and seismic data indicate that the gas hydrate occurs within complex combination stratigraphic/structural traps. Structural trapping is provided by a four-way fold closure augmented by a large western bounding fault. Lithologic variation is also a likely strong control on lateral extent of the reservoirs, particularly in the D unit accumulation, where gas hydrate appears to extend beyond the limits of the structural closure. Porous and permeable zones within the C unit sand are only partially charged due most likely to limited structural trapping in the reservoir lithofacies during the period of primary charging. The occurrence of the gas hydrate within the sands in the upper portions of both the C and D units and along the crest of the fold is consistent with an interpretation that these deposits are converted free gas accumulations

  5. 10 CFR 50.44 - Combustible gas control for nuclear power reactors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Combustible gas control for nuclear power reactors. 50.44... for nuclear power reactors. (a) Definitions—(1) Inerted atmosphere means a containment atmosphere with... pressurized water nuclear power reactor with an operating license on October 16, 2003, except for...

  6. 10 CFR 50.44 - Combustible gas control for nuclear power reactors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Combustible gas control for nuclear power reactors. 50.44... for nuclear power reactors. (a) Definitions—(1) Inerted atmosphere means a containment atmosphere with... pressurized water nuclear power reactor with an operating license on October 16, 2003, except for...

  7. 10 CFR 50.44 - Combustible gas control for nuclear power reactors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Combustible gas control for nuclear power reactors. 50.44 Section 50.44 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION... for nuclear power reactors. (a) Definitions—(1) Inerted atmosphere means a containment atmosphere...

  8. 10 CFR 50.44 - Combustible gas control for nuclear power reactors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Combustible gas control for nuclear power reactors. 50.44 Section 50.44 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION... for nuclear power reactors. (a) Definitions—(1) Inerted atmosphere means a containment atmosphere...

  9. 10 CFR 50.44 - Combustible gas control for nuclear power reactors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Combustible gas control for nuclear power reactors. 50.44 Section 50.44 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION... for nuclear power reactors. (a) Definitions—(1) Inerted atmosphere means a containment atmosphere...

  10. Analysis and design of digital output interface devices for gas turbine electronic controls

    NASA Technical Reports Server (NTRS)

    Newirth, D. M.; Koenig, E. W.

    1976-01-01

    A trade study was performed on twenty-one digital output interface schemes for gas turbine electronic controls to select the most promising scheme based on criteria of reliability, performance, cost, and sampling requirements. The most promising scheme, a digital effector with optical feedback of the fuel metering valve position, was designed.

  11. Soil physiochemical controls on trace gas emissions for a North Dakota mollisol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantification of trace gas emissions and an increased understanding of soil controls on emissions during freeze-thaw cycles are essential to refine climate change models. Six similar, intact soil cores were collected to a depth of 80 cm from an undisturbed prairie in central North Dakota. Trace g...

  12. Gas-Phase Formation Rates of Nitric Acid and Its Isomers Under Urban Conditions

    NASA Technical Reports Server (NTRS)

    Okumura, M.; Mollner, A. K.; Fry, J. L.; Feng, L.

    2005-01-01

    Ozone formation in urban smog is controlled by a complex set of reactions which includes radical production from photochemical processes, catalytic cycles which convert NO to NO2, and termination steps that tie up reactive intermediates in long-lived reservoirs. The reaction OH + NO2 + M -4 HONO2 + M (la) is a key termination step because it transforms two short-lived reactive intermediates, OH and NO2, into relatively long-lived nitric acid. Under certain conditions (low VOC/NOx), ozone production in polluted urban airsheds can be highly sensitive to this reaction, but the rate parameters are not well constrained. This report summarizes the results of new laboratory studies of the OH + NO2 + M reaction including direct determination of the overall rate constant and branching ratio for the two reaction channels under atmospherically relevant conditions.

  13. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H₂S and SO₂.

    PubMed

    Dong, Xingchen; Zhang, Xiaoxing; Wu, Xiaoqing; Cui, Hao; Chen, Dachang

    2016-11-10

    Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF₆, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H₂S and SO₂, two decomposed products of SF₆ under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H₂S and SO₂ when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H₂S and SO₂ in gas-insulated switchgears at room temperature.

  14. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H2S and SO2

    PubMed Central

    Dong, Xingchen; Zhang, Xiaoxing; Wu, Xiaoqing; Cui, Hao; Chen, Dachang

    2016-01-01

    Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF6, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H2S and SO2, two decomposed products of SF6 under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H2S and SO2 when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H2S and SO2 in gas-insulated switchgears at room temperature. PMID:27834895

  15. 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

  16. Control rod system useable for fuel handling in a gas-cooled nuclear reactor

    DOEpatents

    Spurrier, Francis R.

    1976-11-30

    A control rod and its associated drive are used to elevate a complete stack of fuel blocks to a position above the core of a gas-cooled nuclear reactor. A fuel-handling machine grasps the control rod and the drive is unlatched from the rod. The stack and rod are transferred out of the reactor, or to a new location in the reactor, by the fuel-handling machine.

  17. Development of natural gas reburning for control of NO sub x from municipal waste combustors

    SciTech Connect

    Abbasi, H.; Tarman, P.B. ); Linz, D.G. )

    1991-01-01

    The Gas Research Institute (GRI) and the Institute of Gas Technology (IGT), in cooperation with Riley Stoker Corporation (Riley), USA, and Takuma Company Ltd. (Takuma), Japan, have developed a gas reburn process for application to municipal waste combustors (MWCs). The reburn process is based on extensive full-scale MWC in-furnace characterization and furnace gas simulation experimental testing. The approach, based on the use of recirculated flue gas to inject and mix natural gas in the reburn zone and control the stoichiometry, was developed and tested in a pilot-scale MWC firing actual municipal waste at a rate of 5.5 metric tons/day. The furnace simulation and the pilot tests define the key process parameters and show that 50% to 70% NO{sub x} reduction can be achieved. A full-scale reburn system has been designed and retrofitted into a full-scale 100-ton/day commercial Riley/Takuma MWC. Field evaluation began in December 1990. This paper describes the results of the development studies and the plans for full-scale system testing. Although the results of full-scale testing are not available for inclusion in this transcript, they will be presented with conclusions at the conference. 2 refs., 10 figs., 5 tabs.

  18. 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.

  19. Gas-phase ion/ion reactions of peptides and proteins: acid/base, redox, and covalent chemistries

    PubMed Central

    Prentice, Boone M.

    2013-01-01

    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. PMID:23257901

  20. The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis.

    PubMed

    Chapman, Pippa J; Clark, Joanna M; Reynolds, Brian; Adamson, John K

    2008-01-01

    Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer.

  1. Strategies to diagnose and control microbial souring in natural gas storage reservoirs and produced water systems

    SciTech Connect

    Morris, E.A.; Derr, R.M.; Pope, D.H.

    1995-12-31

    Hydrogen sulfide production (souring) in natural gas storage reservoirs and produced water systems is a safety and environmental problem that can lead to operational shutdown when local hydrogen sulfide standards are exceeded. Systems affected by microbial souring have historically been treated using biocides that target the general microbial community. However, requirements for more environmentally friendly solutions have led to treatment strategies in which sulfide production can be controlled with minimal impact to the system and environment. Some of these strategies are based on microbial and/or nutritional augmentation of the sour environment. Through research sponsored by the Gas Research Institute (GRI) in Chicago, Illinois, methods have been developed for early detection of microbial souring in natural gas storage reservoirs, and a variety of mitigation strategies have been evaluated. The effectiveness of traditional biocide treatment in gas storage reservoirs was shown to depend heavily on the methods by which the chemical is applied. An innovative strategy using nitrate was tested and proved ideal for produced water and wastewater systems. Another strategy using elemental iodine was effective for sulfide control in evaporation ponds and is currently being tested in microbially sour natural gas storage wells.

  2. An intelligent emissions controller for fuel lean gas reburn in coal-fired power plants.

    PubMed

    Reifman, J; Feldman, E E; Wei, T Y; Glickert, R W

    2000-02-01

    The application of artificial intelligence techniques for performance optimization of the fuel lean gas reburn (FLGR) system is investigated. A multilayer, feedforward artificial neural network is applied to model static nonlinear relationships between the distribution of injected natural gas into the upper region of the furnace of a coal-fired boiler and the corresponding oxides of nitrogen (NOx) emissions exiting the furnace. Based on this model, optimal distributions of injected gas are determined such that the largest NOx reduction is achieved for each value of total injected gas. This optimization is accomplished through the development of a new optimization method based on neural networks. This new optimal control algorithm, which can be used as an alternative generic tool for solving multidimensional nonlinear constrained optimization problems, is described and its results are successfully validated against an off-the-shelf tool for solving mathematical programming problems. Encouraging results obtained using plant data from one of Commonwealth Edison's coal-fired electric power plants demonstrate the feasibility of the overall approach. Preliminary results show that the use of this intelligent controller will also enable the determination of the most cost-effective operating conditions of the FLGR system by considering, along with the optimal distribution of the injected gas, the cost differential between natural gas and coal and the open-market price of NOx emission credits. Further study, however, is necessary, including the construction of a more comprehensive database, needed to develop high-fidelity process models and to add carbon monoxide (CO) emissions to the model of the gas reburn system.

  3. Beyond intestinal soap--bile acids in metabolic control.

    PubMed

    Kuipers, Folkert; Bloks, Vincent W; Groen, Albert K

    2014-08-01

    Over the past decade, it has become apparent that bile acids are involved in a host of activities beyond their classic functions in bile formation and fat absorption. The identification of the farnesoid X receptor (FXR) as a nuclear receptor directly activated by bile acids and the discovery that bile acids are also ligands for the membrane-bound, G-protein coupled bile acid receptor 1 (also known as TGR5) have opened new avenues of research. Both FXR and TGR5 regulate various elements of glucose, lipid and energy metabolism. Consequently, a picture has emerged of bile acids acting as modulators of (postprandial) metabolism. Therefore, strategies that interfere with either bile acid metabolism or signalling cascades mediated by bile acids may represent novel therapeutic approaches for metabolic diseases. Synthetic modulators of FXR have been designed and tested, primarily in animal models. Furthermore, the use of bile acid sequestrants to reduce plasma cholesterol levels has unexpected benefits. For example, treatment of patients with type 2 diabetes mellitus (T2DM) with sequestrants causes substantial reductions in plasma levels of glucose and HbA1c. This Review aims to provide an overview of the molecular mechanisms by which bile acids modulate glucose and energy metabolism, particularly focusing on the glucose-lowering actions of bile acid sequestrants in insulin resistant states and T2DM.

  4. 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.

  5. Preparing ultrafine PbS powders from the scrap lead-acid battery by sulfurization and inert gas condensation

    NASA Astrophysics Data System (ADS)

    Xia, Huipeng; Zhan, Lu; Xie, Bing

    2017-02-01

    A novel method for preparing ultrafine PbS powders involving sulfurization combined with inert gas condensation is developed in this paper, which is applicable to recycle Pb from lead paste of spent lead-acid batteries. Initially, the effects of the evaporation and condensation temperature, the inert gas pressure, the condensation distance and substrate on the morphology of as-obtained PbS ultrafine particles are intensively investigated using sulfur powders and lead particles as reagents. Highly dispersed and homogeneous PbS nanoparticles can be prepared under the optimized conditions which are 1223 K heating temperature, 573 K condensation temperature, 100 Pa inert gas pressure and 60 cm condensation distance. Furthermore, this method is successfully applied to recycle Pb from the lead paste of spent lead acid battery to prepare PbS ultrafine powders. This work does not only provide the theoretical fundamental for PbS preparation, but also provides a novel and efficient method for recycling spent lead-acid battery with high added-value products.

  6. 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.

  7. Controls on methane expulsion during melting of natural gas hydrate systems. Topic area 2

    SciTech Connect

    Flemings, Peter

    2016-01-14

    1.1. Project Goal The project goal is to predict, given characteristic climate-induced temperature change scenarios, the conditions under which gas will be expelled from existing accumulations of gas hydrate into the shallow ocean or directly to the atmosphere. When those conditions are met, the fraction of the gas accumulation that escapes and the rate of escape shall be quantified. The predictions shall be applicable in Arctic regions and in gas hydrate systems at the up dip limit of the stability zone on continental margins. The behavior shall be explored in response to two warming scenarios: longer term change due to sea level rise (e.g. 20 thousand years) and shorter term due to atmospheric warming by anthropogenic forcing (decadal time scale). 1.2. Project Objectives During the first budget period, the objectives are to review and categorize the stability state of existing well-studied hydrate reservoirs, develop conceptual and numerical models of the melting process, and to design and conduct laboratory experiments that dissociate methane hydrate in a model sediment column by systematically controlling the temperature profile along the column. The final objective of the first budget period shall be to validate the models against the experiments. In the second budget period, the objectives are to develop a model of gas flow into sediment in which hydrate is thermodynamically stable, and conduct laboratory experiments of this process to validate the model. The developed models shall be used to quantify the rate and volume of gas that escapes from dissociating hydrate accumulations. In addition, specific scaled simulations characteristic of Arctic regions and regions near the stability limit at continental margins shall be performed. 1.3. Project Background and Rationale The central hypothesis proposed is that hydrate melting (dissociation) due to climate change generates free gas that can, under certain conditions, propagate through the gas hydrate stability

  8. Light-induced multiphase chemistry of gas phase ozone on aqueous pyruvic and oxalic acids: Aerosol chamber study

    NASA Astrophysics Data System (ADS)

    Gligorovski, S.; Grgic, I.; Net, S.; Böge, O.; Iinuma, Y.; Kahnt, A.; Scheinhardt, S.; Herrmann, H.; Wortham, H.

    2010-12-01

    The light-absorbing organic compounds present in and on condensed aerosol particles interacting with trace gases such as ozone can initiate a new and potentially important photo-induced multiphase chemistry. However, investigations of light induced multiphase processes are very scarce at present. We have launched the idea of pyruvic acid (PA) acting as a photosensitizer in the multiphase reactions between gas-phase ozone and aqueous oxalic acid (OA). The performed photochemical batch experiments yielded a complex suite of organic molecules which resulted primarily from the oligomerization of OA/PA and subsequent reactions, including decarboxylation and cycloadition (Grgic et al., 2010). In the atmosphere, pyruvic acid will always be accompanied by other carboxylic acids (and also other organics) which are constituents of either aerosol particles or aqueous droplets the effects of a possible photochemistry triggered by pyruvic acid should be experimentally studied in depth and under natural conditions as far as possible. Hence, in a very recent study experiments in the aerosol chamber facility LEAK at IFT, Leipzig, were performed to verify the influence of pyruvic on the multiphase (photo)oxidation of oxalic acid. The aim of these experiments was to study the multiphase photo-induced oxidation reactions with airborne deliquescent particles to demonstrate the applicability of the reactions mentioned above under more realistic conditions than in a batch reactor. State of the art sampling and analytical tools were applied for the analysis of the ongoing chamber runs and the formed particulate products which include denuder sampling, carbonyl compound derivatisation, PTR-MS measurements, GC-MS measurements and HPLC-MS and CE-MS for the particle phase. First results from these joint complex chamber experiments will be presented and discussed. Reference: Grgić I., Nieto-Gligorovski L.I., Net S., Temime-Roussel B., Gligorovski S., Wortham H. Light induced multiphase

  9. 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.

  10. 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

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

    PubMed

    Jafari, Mohammad Javad; Ghasemi, Roohollah; Mehrabi, Yadollah; Yazdanbakhsh, Ahmad Reza; Hajibabaei, Majid

    2012-12-10

    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.

  12. The deep-tow marine controlled-source electromagnetic transmitter system for gas hydrate exploration

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Deng, Ming; Wu, Zhongliang; Luo, Xianhu; Jing, Jianen; Chen, Kai

    2017-02-01

    The Marine Controlled-Source Electromagnetic (MCSEM) method has been recognized as an important and effective tool to detect electrically resistive structures, such as oil, gas, and gas hydrate. The MCSEM performance is strongly influenced by the transmitter system design. We have developed a deep-tow MCSEM transmitter system. In this paper, some new technical details will be present. A 10,000 m optical-electrical composite cable is used to support high power transmission and fast data transfer; a new clock unit is designed to keep the synchronization between transmitter and receivers, and mark the time stamp into the transmission current full waveform; a data link is established to monitor the real-time altitude of the tail unit; an online insulation measuring instrument is adopted to monitor current leakage from high voltage transformer; a neutrally buoyant dipole antenna of copper cable and flexible electrodes are created to transmit the large power current into seawater; a new design method for the transmitter, which is called "real-time control technology of hardware parallelism", is described to achieve inverting and recording high-power current waveform, controlling functions, and collecting auxiliary information. We use a gas hydrate exploration test to verify the performance of the transmitter system, focusing on more technical details, rather than applications. The test shows that the transmitter can be used for gas hydrate exploration as an effective source.

  13. Tracking and Control of Gas Turbine Engine Component Damage/Life

    NASA Technical Reports Server (NTRS)

    Jaw, Link C.; Wu, Dong N.; Bryg, David J.

    2003-01-01

    This paper describes damage mechanisms and the methods of controlling damages to extend the on-wing life of critical gas turbine engine components. Particularly, two types of damage mechanisms are discussed: creep/rupture and thermo-mechanical fatigue. To control these damages and extend the life of engine hot-section components, we have investigated two methodologies to be implemented as additional control logic for the on-board electronic control unit. This new logic, the life-extending control (LEC), interacts with the engine control and monitoring unit and modifies the fuel flow to reduce component damages in a flight mission. The LEC methodologies were demonstrated in a real-time, hardware-in-the-loop simulation. The results show that LEC is not only a new paradigm for engine control design, but also a promising technology for extending the service life of engine components, hence reducing the life cycle cost of the engine.

  14. Pentafluorobenzyl esterification of haloacetic acids in tap water for simple and sensitive analysis by gas chromatography/mass spectrometry with negative chemical ionization.

    PubMed

    Zhao, Can; Fujii, Yukiko; Yan, Junxia; Harada, Kouji H; Koizumi, Akio

    2015-01-01

    Chlorine is the most widely used disinfectant for control of waterborne diseases in drinking water treatment. It can react with natural organic matter in water and form haloacetic acids (HAAs). For analysis of HAA levels, derivatization with diazomethane is commonly recommended as the standard methodology in Japan. However, diazomethane is a carcinogenic alkylating agent. Therefore, in this study, a safe, simple, and sensitive quantification method was developed to monitor HAAs in drinking water. Pentafluorobenzyl esterification was used for pretreatment. The pentafluorobenzyl-ester derivative was detected by gas chromatography-negative ion chemical ionization-mass spectrometry analysis with very high sensitivity for HAAs analysis. The method has low detection limits (8-94 ng L(-1)) and good recovery rates (89-99%) for HAAs. The method was applied to 30 tap water samples from 15 cities in the Kansai region of Japan. The levels of HAAs detected were in the range 0.54-7.83 μg L(-1). Dichloroacetic acid, trichloroacetic acid, and bromochloroacetic acid were the major HAAs detected in most of the tap water, and accounted for 29%, 20% and 19% of the total HAAs, respectively. This method could be used for routine monitoring of HAAs in drinking water without exposure of workers to occupational hazards.

  15. Iron control in west Texas sour-gas wells provides sustained production increases

    SciTech Connect

    Walker, M.L.; Dill, W.R.; Besler, M.R.; McFatridge, D.G. )

    1991-05-01

    Permian Basin operators have recorded sustained production increases in oil wells by preventing precipitation of iron sulfide and other sulfur-containing species. This improvement has resulted largely from cleaning out tubing before acidizing and from preventing the precipitation of ferrous sulfide and the formation of elemental sulfur by simultaneous use of iron chelants and sulfide-control agents. Previously used methods gave only temporary production increases that terminated when iron dissolved by the stimulation acid reprecipitated in the pay zone and damage the formation after the stimulation acid was spent. This paper describes a method to optimize iron sulfide control, methods to minimize reprecipitation, and case histories from the Permian Basin that show improved methods to control iron in sour-well environments.

  16. Control Decisions for Flammable Gas Hazards in Double Contained Receiver Tanks (DCRTs)

    SciTech Connect

    KRIPPS, L.J.

    2000-06-28

    This report describes the control decisions for flammable gas hazards in double-contained receiver tanks (DCRTs) made at control decision meetings on November 16, 17, and 18, 1999, on April 19,2000, and on May 10,2000, and their basis. These control decisions, and the analyses that support them, will be documented in an amendment to the Final Safety Analysis Report (FSAR) (CHG 2000a) and Technical Safety Requirements (TSR) (CHG 2000b) to close the Flammable Gas Unreviewed Safety Question (USQ) (Bacon 1996 and Wagoner 1996) for DCRTs. Following the contractor Tier I review of the FSAR and TSR amendment, it will be submitted to the U.S. Department of Energy (DOE), Office of River Protection (ORP) for review and approval.

  17. Control of Nitrogen Oxide Emissions by Hydrogen Peroxide-Enhanced Gas-Phase Oxidation Of Nitric Oxide.

    PubMed

    Kasper, John M; Iii, Christian A Clausen; Cooper, C David

    1996-02-01

    Nitrogen oxides (NOX) and sulfur oxides (SOX) are criteria air pollutants, emitted in large quantities from fossil-fueled electric power plants. Emissions of SOX are currently being reduced significantly in many places by wet scrubbing of the exhaust or flue gases, but most of the NOX in the flue gases is NO, which is so insoluble that it is virtually impossible to scrub. Consequently, NOX control is mostly achieved by using combustion modifications to limit the formation of NOX, or by using chemical reduction techniques to reduce NOX to N2. Low NOX burners are relatively inexpensive but can only achieve about 50% reduction in NOX emissions; selective catalytic reduction (SCR) can achieve high reductions but is very expensive. The removal of NOX in wet scrubbers could be greatly enhanced by gas-phase oxidation of the NO to NO2, HNO2, and HNO3 (the acid gases are much more soluble in water than NO). This oxidation is accomplished by injecting liquid hydrogen peroxide into the flue gas; the H2O2 vaporizes and dissociates into hydroxyl radicals. The active OH radicals then oxidize the NO and NO2. This NOX control technique might prove economically feasible at power plants with existing SO2 scrubbers. The higher chemical costs for H2O2 would be balanced by the investment cost savings, compared with an alternative such as SCR. The oxidation of NOX by using hydrogen peroxide has been demonstrated in a laboratory quartz tube reactor. NO conversions of 97% and 75% were achieved at hydrogen peroxide/NO mole ratios of 2.6 and 1.6, respectively. The reactor conditions (500 °C, a pressure of one atmosphere, and 0.7 seconds residence time) are representative of flue gas conditions for a variety of combustion sources. The oxidized NOX species were removed by caustic water scrubbing.

  18. Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment

    SciTech Connect

    Nick Soelberg

    2005-09-01

    Treatment of radioactive and mixed wastes is often required to destroy or immobilize hazardous constituents, reduce waste volume, and convert the waste to a form suitable for final disposal. These kinds of treatments usually evolve off-gas. Air emission regulations have become increasingly stringent in recent years. Mixed waste thermal treatment in the United States is now generally regulated under the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. These standards impose unprecedented requirements for operation, monitoring and control, and emissions control. Off-gas control technologies and system designs that were satisfactorily proven in mixed waste operation prior to the implementation of new regulatory standards are in some cases no longer suitable in new mixed waste treatment system designs. Some mixed waste treatment facilities have been shut down rather than have excessively restrictive feed rate limits or facility upgrades to comply with the new standards. New mixed waste treatment facilities in the U. S. are being designed to operate in compliance with the HWC MACT standards. Activities have been underway for the past 10 years at the INL and elsewhere to identify, develop, demonstrate, and design technologies for enabling HWC MACT compliance for mixed waste treatment facilities. Some specific off-gas control technologies and system designs have been identified and tested to show that even the stringent HWC MACT standards can be met, while minimizing treatment facility size and cost.

  19. Characterization and chemical composition of fatty acids content of watermelon and muskmelon cultivars in Saudi Arabia using gas chromatography/mass spectroscopy

    PubMed Central

    Albishri, Hassan M.; Almaghrabi, Omar A.; Moussa, Tarek A. A.

    2013-01-01

    Background: The growth in the production of biodiesel, which is principally fatty acid methyl esters (FAME), has been phenomenal in the last ten years because of the general desire to cut down on the release of greenhouse gases into the atmosphere, and also as a result of the increasing cost of fossil fuels. Objective: Establish whether there is any relationship between two different species (watermelon and muskmelon) within the same family (Cucurbitaceae) on fatty acid compositions and enumerate the different fatty acids in the two species. Materials and Methods: Extraction of fatty acids from the two species and preparation the extract to gas chromatography/mass spectroscopy analysis to determine the fatty acids compositions qualitatively and quantitatively. Results: The analyzed plants (watermelon and muskmelon) contain five saturated fatty acids; tetrdecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid and octadecanoic acid with different concentrations, while muskmelon contains an extra saturated fatty acid named eicosanoic acid. The watermelon plant contains five unsaturated fatty acids while muskmelon contains three only, the two plants share in two unsaturated fatty acids named 9-hexadecenoic acid and 9-octadecenoic acid, the muskmelon plant contains higher amounts of these two acids (2.04% and 10.12%, respectively) over watermelon plant (0.88% and 0.25%, respectively). Conclusion: The chemical analysis of watermelon and muskmelon revealed that they are similar in saturated fatty acids but differ in unsaturated fatty acids which may be a criterion of differentiation between the two plants. PMID:23661995

  20. 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.