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Sample records for chemical air separation

  1. Corrosion study in the chemical air separation (MOLTOX trademark ) process

    SciTech Connect

    Kang, Doohee; Wong, Kai P.; Archer, R.A.; Cassano, A.A.

    1988-12-01

    This report presents the results of studies aimed at solving the corrosion problems encountered during operation of the MOLTOX{trademark} pilot plant. These studies concentrated on the screening of commercial and developmental alloys under conditions simulating operation conditions in this high temperature molten salt process. Process economic studies were preformed in parallel with the laboratory testing to ensure that an economically feasible solution would be achieved. In addition to the above DOE co-funded studies, Air Products and Chemicals pursued proprietary studies aimed at developing a less corrosive salt mixture which would potentially allow the use of chemurgically available alloys such as stainless steels throughout the system. These studies will not be reported here; however, the results of corrosion tests in the new less corrosive salt mixtures are reported. Because our own studies on salt chemistry impacts heavily on the overall process and thereby has an influence on the experimental work conducted under this contract, some of the studies discussed here were impacted by our own proprietary data. Therefore, the reasons behind some of the experiments presented herein will not be explained because that information is proprietary to Air Products. 14 refs., 42 figs., 21 tabs.

  2. Iron aluminides and nickel aluminides as materials for chemical air separation

    DOEpatents

    Kang, D.

    1991-01-29

    The present invention is directed to a chemical air separation process using a molten salt solution of alkali metal nitrate and nitrite wherein the materials of construction of the containment for the process are chosen from intermetallic alloys of nickel and/or iron aluminide wherein the aluminum content is 28 atomic percent or greater to impart enhanced corrosion resistance.

  3. Iron aluminides and nickel aluminides as materials for chemical air separation

    DOEpatents

    Kang, Doohee

    1991-01-01

    The present invention is directed to a chemical air separation process using a molten salt solution of alkali metal nitrate and nitrite wherein the materials of construction of the containment for the process are chosen from intermetallic alloys of nickel and/or iron aluminide wherein the aluminum content is 28 atomic percent or greater to impart enhanced corrosion resistance.

  4. Air separation with temperature and pressure swing

    DOEpatents

    Cassano, Anthony A.

    1986-01-01

    A chemical absorbent air separation process is set forth which uses a temperature swing absorption-desorption cycle in combination with a pressure swing wherein the pressure is elevated in the desorption stage of the process.

  5. Airborne rotary air separator study

    NASA Technical Reports Server (NTRS)

    Acharya, A.; Gottzmann, C. F.; Nowobilski, J. J.

    1990-01-01

    Several air breathing propulsion concepts for future earth-to-orbit transport vehicles utilize air collection and enrichment, and subsequent storage of liquid oxygen for later use in the vehicle emission. Work performed during the 1960's established the feasibility of substantially reducing weight and volume of a distillation type air separator system by operating the distillation elements in high 'g' fields obtained by rotating the separator assembly. This contract studied the capability test and hydraulic behavior of a novel structured or ordered distillation packing in a rotating device using air and water. Pressure drop and flood points were measured for different air and water flow rates in gravitational fields of up to 700 g. Behavior of the packing follows the correlations previously derived from tests at normal gravity. The novel ordered packing can take the place of trays in a rotating air separation column with the promise of substantial reduction in pressure drop, volume, and system weight. The results obtained in the program are used to predict design and performance of rotary separators for air collection and enrichment systems of interest for past and present concepts of air breathing propulsion (single or two-stage to orbit) systems.

  6. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, Robert F.

    1987-01-01

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs.

  7. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, R.F.

    1987-11-24

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs. 4 figs.

  8. Separations Needs for the Alternate Chemical Cycles

    SciTech Connect

    Frederick F. Stewart

    2007-05-01

    The bulk of the efforts for the development of a hydrogen production plant supported by the Nuclear Hydrogen Initiative (NHI) have been directed towards the sulfur-iodine (S-I) thermochemical cycle. However, it was judged prudent to re-investigate alternate chemical cycles in light of new developments and technical accomplishments derived from the current S-I work. This work analyzes the available data for the promising alternate chemical cycles to provide an understanding of their inherent chemical separations needs. None of the cycles analyzed have separations that are potential “show stoppers”; although some of the indicated separations will be challenging to perform. The majority of the separations involve processes that are either more achievable or more developed

  9. Activated Carbon Composites for Air Separation

    SciTech Connect

    Contescu, Cristian I; Baker, Frederick S; Tsouris, Costas; McFarlane, Joanna

    2008-03-01

    In continuation of the development of composite materials for air separation based on molecular sieving properties and magnetic fields effects, several molecular sieve materials were tested in a flow system, and the effects of temperature, flow conditions, and magnetic fields were investigated. New carbon materials adsorbents, with and without pre-loaded super-paramagnetic nanoparticles of Fe3O4 were synthesized; all materials were packed in chromatographic type columns which were placed between the poles of a high intensity, water-cooled, magnet (1.5 Tesla). In order to verify the existence of magnetodesorption effect, separation tests were conducted by injecting controlled volumes of air in a flow of inert gas, while the magnetic field was switched on and off. Gas composition downstream the column was analyzed by gas chromatography and by mass spectrometry. Under the conditions employed, the tests confirmed that N2 - O2 separation occurred at various degrees, depending on material's intrinsic properties, temperature and flow rate. The effect of magnetic fields, reported previously for static conditions, was not confirmed in the flow system. The best separation was obtained for zeolite 13X at sub-ambient temperatures. Future directions for the project include evaluation of a combined system, comprising carbon and zeolite molecular sieves, and testing the effect of stronger magnetic fields produced by cryogenic magnets.

  10. The method for on-site determination of trace concentrations of methyl mercaptan and dimethyl sulfide in air using a mobile mass spectrometer with atmospheric pressure chemical ionization, combined with a fast enrichment/separation system.

    PubMed

    Kudryavtsev, Andrey S; Makas, Alexey L; Troshkov, Mikhail L; Grachev, Mikhail А; Pod'yachev, Sergey P

    2014-06-01

    A method for fast simultaneous on-site determination of methyl mercaptan and dimethyl sulfide in air was developed. The target compounds were actively collected on silica gel, followed by direct flash thermal desorption, fast separation on a short chromatographic column and detection by means of mass spectrometer with atmospheric pressure chemical ionization. During the sampling of ambient air, water vapor was removed with a Nafion selective membrane. A compact mass spectrometer prototype, which was designed earlier at Trofimuk Institute of Petroleum Geology and Geophysics, was used. The minimization of gas load of the atmospheric pressure ion source allowed reducing the power requirements and size of the vacuum system and increasing its ruggedness. The measurement cycle is about 3 min. Detection limits in a 0.6 L sample are 1 ppb for methyl mercaptan and 0.2 ppb for dimethyl sulfide. PMID:24725876

  11. SAMPLING FOR ORGANIC CHEMICALS IN AIR

    EPA Science Inventory

    Organic chemicals by far account for the majority of pollutants found in air. ore than 90% of the 75,000 chemicals listed in EPA's Toxic Substances Control Act Chemical Substance Inventory and 88% of the 189 Hazardous Air Pollutants (HAPS) named in the Clean Air Act Amendments of...

  12. Air Separation Using Hollow Fiber Membranes

    NASA Technical Reports Server (NTRS)

    Huang, Stephen E.

    2004-01-01

    The NASA Glenn Research Center in partnership with the Ohio Aerospace Institute provides internship programs for high school and college students in the areas of science, engineering, professional administrative, and other technical areas. During the summer of 2004, I worked with Dr. Clarence T. Chang at NASA Glenn Research Center s combustion branch on air separation using hollow fiber membrane technology. . In light of the accident of Trans World Airline s flight 800, FAA has mandated that a suitable solution be created to prevent the ignition of fuel tanks in aircrafts. In order for any type of fuel to ignite, three important things are needed: fuel vapor, oxygen, and an energy source. Two different ways to make fuel tanks less likely to ignite are reformulating the fuel to obtain a lower vapor pressure for the fuel and or using an On Board Inert Gas Generating System (OBIGGS) to inert the Central Wing Tank. goal is to accomplish the mission, which means that the Air Separation Module (ASM) tends to be bulky and heavy. The primary goal for commercial aviation companies is to transport as much as they can with the least amount of cost and fuel per person, therefore the ASM must be compact and light as possible. The plan is to take bleed air from the aircraft s engines to pass air through a filter first to remove particulates and then pass the air through the ASM containing hollow fiber membranes. In the lab, there will be a heating element provided to simulate the temperature of the bleed air that will be entering the ASM and analysis of the separated air will be analyzed by a Gas Chromatograph/Mass Spectrometer (GC/MS). The GUMS will separate the different compounds in the exit streams of the ASM and provide information on the performance of hollow fiber membranes. Hopefully I can develop ways to improve efficiency of the ASM. different types of jet fuel were analyzed and data was well represented on SAE Paper 982485. Data consisted of the concentrations of over

  13. A Cabin Air Separator for EVA Oxygen

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2011-01-01

    Presently, the Extra-Vehicular Activities (EVAs) conducted from the Quest Joint Airlock on the International Space Station use high pressure, high purity oxygen that is delivered to the Space Station by the Space Shuttle. When the Space Shuttle retires, a new method of delivering high pressure, high purity oxygen to the High Pressure Gas Tanks (HPGTs) is needed. One method is to use a cabin air separator to sweep oxygen from the cabin air, generate a low pressure/high purity oxygen stream, and compress the oxygen with a multistage mechanical compressor. A main advantage to this type of system is that the existing low pressure oxygen supply infrastructure can be used as the source of cabin oxygen. ISS has two water electrolysis systems that deliver low pressure oxygen to the cabin, as well as chlorate candles and compressed gas tanks on cargo vehicles. Each of these systems can feed low pressure oxygen into the cabin, and any low pressure oxygen source can be used as an on-board source of oxygen. Three different oxygen separator systems were evaluated, and a two stage Pressure Swing Adsorption system was selected for reasons of technical maturity. Two different compressor designs were subjected to long term testing, and the compressor with better life performance and more favorable oxygen safety characteristics was selected. These technologies have been used as the basis of a design for a flight system located in Equipment Lock, and taken to Preliminary Design Review level of maturity. This paper describes the Cabin Air Separator for EVA Oxygen (CASEO) concept, describes the separator and compressor technology trades, highlights key technology risks, and describes the flight hardware concept as presented at Preliminary Design Review (PDR)

  14. Activated Carbon Composites for Air Separation

    SciTech Connect

    Baker, Frederick S; Contescu, Cristian I; Tsouris, Costas; Burchell, Timothy D

    2011-09-01

    Coal-derived synthesis gas is a potential major source of hydrogen for fuel cells. Oxygen-blown coal gasification is an efficient approach to achieving the goal of producing hydrogen from coal, but a cost-effective means of enriching O2 concentration in air is required. A key objective of this project is to assess the utility of a system that exploits porous carbon materials and electrical swing adsorption to produce an O2-enriched air stream for coal gasification. As a complement to O2 and N2 adsorption measurements, CO2 was used as a more sensitive probe molecule for the characterization of molecular sieving effects. To further enhance the potential of activated carbon composite materials for air separation, work was implemented on incorporating a novel twist into the system; namely the addition of a magnetic field to influence O2 adsorption, which is accompanied by a transition between the paramagnetic and diamagnetic states. The preliminary findings in this respect are discussed.

  15. Separation of uranium isotopes by chemical exchange

    DOEpatents

    Ogle, P.R. Jr.

    1974-02-26

    A chemical exchange method is provided for separating /sup 235/U from / sup 238/U comprising contacting a first phase containing UF/sub 6/ with a second phase containing a compound selected from the group consisting of NOUF/sub 6/, NOUF/sub 7/, and NO/sub 2/UF/sub 7/ until the U Fsub 6/ in the first phase becomes enriched in the /sup 235/U isotope. (Official Gazette)

  16. First chemical separation and identification of Seaborgium

    SciTech Connect

    Tuerler, A.; Eichler, B.; Jost, D.T.; Hoffman, D.C.

    1997-12-31

    The chemical properties of element 106 (Seaborgium, Sg) were successfully studied using the On-line Gas Chromatography Apparatus (OLGA III). After chemical separation of Sg in the form of volatile oxichlorides the nuclides {sup 265}Sg and {sup 266}Sg were unambiguously identified and their half-lives were determined for the first time. The Sg nuclides were produced from the {sup 248}Cm({sup 22}Ne, 4,5n){sup 266,265}Sg reaction at the GSI Darmstadt UNILAC accelerator. Simultaneously, short-lived W nuclides were produced from a small admixture of {sup 152}Gd to the Cm target material. As predicted by relativistic calculations and by extrapolations of chemical properties, it was demonstrated that Sg oxichlorides are indeed less volatile than their lighter homologue W- and Mo-oxichlorides.

  17. Hybrid membrane--PSA system for separating oxygen from air

    DOEpatents

    Staiger, Chad L.; Vaughn, Mark R.; Miller, A. Keith; Cornelius, Christopher J.

    2011-01-25

    A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

  18. RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES

    SciTech Connect

    Maxwell, S.; Noyes, G.; Culligan, B.

    2010-02-03

    A new rapid method for the determination of actinides and strontium in air filter samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations. The actinides and strontium in air filter method utilizes a rapid acid digestion method and a streamlined column separation process with stacked TEVA, TRU and Sr Resin cartridges. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha emitters are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency air filter samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinide and {sup 90}Sr in air filter results were reported in {approx}4 hours with excellent quality.

  19. Oxygen separation from air using zirconia solid electrolyte membranes

    NASA Technical Reports Server (NTRS)

    Suitor, J. W.; Marner, W. J.; Schroeder, J. E.; Losey, R. W.; Ferrall, J. F.

    1988-01-01

    Air separation using a zirconia solid electrolyte membrane is a possible alternative source of oxygen. The process of zirconia oxygen separation is reviewed, and an oxygen plant concept using such separation is described. Potential cell designs, stack designs, and testing procedures are examined. Fabrication of the materials used in a zirconia module as well as distribution plate design and fabrication are examined.

  20. 104. North Carolina Route 1130 grade separation structure at Air ...

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

    104. North Carolina Route 1130 grade separation structure at Air Bellows Gap. Detail of the stepped wing wall. Looking southwest. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  1. 103. North Carolina Route 1130 grade separation structure at Air ...

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

    103. North Carolina Route 1130 grade separation structure at Air Bellows Gap. Elevation view of concrete slab bridge built in 1937. Looking southeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  2. 105. North Carolina Route 1130 grade separation structure at Air ...

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

    105. North Carolina Route 1130 grade separation structure at Air Bellows Gap. View showing the access road from the parkway. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  3. Chemical air pollutants and otorhinolaryngeal toxicity

    SciTech Connect

    Bisesi, M.S.; Rubin, A.M. . Occupational Health and Otolaryngology)

    1994-03-01

    Air pollution and the specific issue regarding the impact of airborne chemical agents to human health are familiar topics to most members of the environmental health science and environmental medicine communities. Some aspects, however, have received relatively less attention. Much has been published regarding the impact of air pollutants on the human upper and lower respiratory system, including interaction with the rhinologic (nasal) system. Relatively fewer data have been published, however, regarding the potential impact of air pollutants in reference specifically to the otologic (auditory and vestibular) and the laryngeal (larynx) system. Adverse impact to the ears, nose and throat, referred to as the otorhinolaryngeal system'', warrants attention as an important environmental health issue. Toxic interactions from exposure to many chemical air pollutants not only causes potential respiratory irritation and lung disease, but can also result in impaired hearing, balance, sense of smell, taste, and speech due to interaction with related target systems. This may be significant to environmental health risk assessment of chemical air pollutants if multi-target site models are considered.

  4. CHEMICAL SEPARATION AND IN SITU MUTAGENICITY TESTING

    EPA Science Inventory

    The traditional way to characterize a complex sample has been by chemical analysis to identify the individual components. However, unknown or overlooked mutagens or carcinogens may remain undetected by this method. In recent years a combination of chemical analysis and mutagenici...

  5. Laser separation of chemically strengthened glass

    NASA Astrophysics Data System (ADS)

    Abramov, Anatoli A.; Black, Matthew L.; Scott Glaesemann, G.

    A laser method for separating the strengthened glass and the effect of this process on edge quality and strength are reported. We have shown, for the first time to our knowledge, that developed laser based cutting technique enables clean full separation of the strengthened glass sheets having high level of ion exchange without spontaneous cracking or shattering. Nearly 'flaw-free' edge was achieved after optimization of the laser cutting parameters and after defining of an optimum range of the central tension inside the glass. As a result, high strength of the edge of > 500 MPa is demonstrated for the first time.

  6. AIR SEPARATION BY PRESSURE SWING ADSORPTION USING SUPERIOR ADSORBENTS

    SciTech Connect

    Ralph T. Yang

    2001-08-31

    Li-X zeolite (Si/Al = 1.0) is currently the best sorbent for use in the separation of air by adsorption processes. In particular, pressure swing adsorption (PSA) using zeolite sorbents is being increasingly used for air separation. Silver is also known to strongly affect the adsorptive properties of zeolites; and it is known that thermal vacuum dehydration of silver zeolites leads to the formation of silver clusters within the zeolite. In this work we have synthesized type X zeolites containing Ag and also varying mixtures of Li and Ag. In this project, we developed the Ag-containing zeolite as the best sorbent for air separation. We have also studied Co-ligand compounds as oxygen-selective sorbents. Syntheses, structural characterization and adsorption properties have been performed on all sorbents. The results are described in detail in 5 chapters.

  7. Process study and exergy analysis of a novel air separation process cooled by LNG cold energy

    NASA Astrophysics Data System (ADS)

    Xu, Wendong; Duan, Jiao; Mao, Wenjun

    2014-02-01

    In order to resolve the problems of the current air separation process such as the complex process, cumbersome operation and high operating costs, a novel air separation process cooled by LNG cold energy is proposed in this paper, which is based on high-efficiency heat exchanger network and chemical packing separation technology. The operating temperature range of LNG cold energy is widened from 133K-203K to 113K-283K by high-efficiency heat exchanger network and air separation pressure is declined from 0.5MPa to about 0.35MPa due to packing separation technology, thereby greatly improve the energy efficiency. Both the traditional and novel air separation processes are simulated with air handling capacity of 20t·h-1. Comparing with the traditional process, the LNG consumption is reduced by 44.2%, power consumption decrease is 211.5 kWh per hour, which means the annual benefit will be up to 1.218 million CNY. And the exergy efficiency is also improved by 42.5%.

  8. Air Flow in a Separating Laminar Boundary Layer

    NASA Technical Reports Server (NTRS)

    Schubauer, G B

    1936-01-01

    The speed distribution in a laminar boundary layer on the surface of an elliptic cylinder, of major and minor axes 11.78 and 3.98 inches, respectively, has been determined by means of a hot-wire anemometer. The direction of the impinging air stream was parallel to the major axis. Special attention was given to the region of separation and to the exact location of the point of separation. An approximate method, developed by K. Pohlhausen for computing the speed distribution, the thickness of the layer, and the point of separation, is described in detail; and speed-distribution curves calculated by this method are presented for comparison with experiment.

  9. Air separation by the Moltox process. Interim final report

    SciTech Connect

    Erickson, D.C.

    1981-04-01

    Results are described of a development program on a new and energy-saving process for air separation. The Moltox process involves reversibly reacting oxygen in air with a recirculating salt solution, such that oxygen is extracted without depressurizing the remaining nitrogen. Energy savings of approximately 50% are indicated for this process compared to conventional cryogenic air separation. The development program consisted of design, construction, and operation of a 6 liter/minute pilot plant; optimization of the process flowsheet through computer modelling; investigation of engineering aspects of the process including corrosion, safety, and NO/sub x/ generation; and an economic comparison to conventional cryogenic practice. All objectives were satisfactorily achieved except for continuous operation of the pilot plant, and the modifications necessary to achieve that have been identified. Economically the Moltox process shows a substantial advantage over large scale cryogenic plants which are powered by fuel vice electricity.

  10. Combined air stripper/membrane vapor separation systems. Final report

    SciTech Connect

    Wijmans, J.G.; Baker, R.W.; Kamaruddin, H.D.; Kaschemekat, J.; Olsen, R.P.; Rose, M.E.; Segelke, S.V.

    1992-11-01

    Air stripping is an economical and efficient method of removing dissolved volatile organic compounds (VOCs) from contaminated groundwater. Air strippers, however, produce a vent air stream, which must meet the local air quality limits. If the VOC content exceeds the limits, direct discharge is not possible; therefore, a carbon adsorption VOC capture system is used to treat the vent air. This treatment step adds a cost of at least $50/lb of VOC captured. In this program, a combined air stripper/membrane vapor separation system was constructed and demonstrated in the laboratory. The membrane system captures VOCs from the stripper vent stream at a projected cost of $15/lb VOC for a water VOC content of 5 ppmw, and $75/lb VOC for a water VOC content of 1 ppmw. The VOCs are recovered as a small, concentrated liquid fraction for disposal or solvent recycling. The concept has been demonstrated in experiments with a system capable of handling up to 150,000 gpd of water. The existing demonstration system is available for field tests at a DOE facility or remediation site. Replacement of the current short air stripping tower (effective height 3 m) with a taller tower is recommended to improve VOC removal.

  11. Parametric Studies of Flow Separation using Air Injection

    NASA Technical Reports Server (NTRS)

    Zhang, Wei

    2004-01-01

    Boundary Layer separation causes the airfoil to stall and therefore imposes dramatic performance degradation on the airfoil. In recent years, flow separation control has been one of the active research areas in the field of aerodynamics due to its promising performance improvements on the lifting device. These active flow separation control techniques include steady and unsteady air injection as well as suction on the airfoil surface etc. This paper will be focusing on the steady and unsteady air injection on the airfoil. Although wind tunnel experiments revealed that the performance improvements on the airfoil using injection techniques, the details of how the key variables such as air injection slot geometry and air injection angle etc impact the effectiveness of flow separation control via air injection has not been studied. A parametric study of both steady and unsteady air injection active flow control will be the main objective for this summer. For steady injection, the key variables include the slot geometry, orientation, spacing, air injection velocity as well as the injection angle. For unsteady injection, the injection frequency will also be investigated. Key metrics such as lift coefficient, drag coefficient, total pressure loss and total injection mass will be used to measure the effectiveness of the control technique. A design of experiments using the Box-Behnken Design is set up in order to determine how each of the variables affects each of the key metrics. Design of experiment is used so that the number of experimental runs will be at minimum and still be able to predict which variables are the key contributors to the responses. The experiments will then be conducted in the 1ft by 1ft wind tunnel according to the design of experiment settings. The data obtained from the experiments will be imported into JMP, statistical software, to generate sets of response surface equations which represent the statistical empirical model for each of the metrics as

  12. Carbon molecular sieves for air separation from Nomex aramid fibers.

    PubMed

    Villar-Rodil, Silvia; Martínez-Alonso, Amelia; Tascón, Juan M D

    2002-10-15

    Activated carbon fibers prepared from aramid fibers have proved to possess outstanding homogeneity in pore size, most of all when Nomex aramid fiber is used as precursor. Taking advantage of this feature, microporous carbon molecular sieves for air separation have been prepared through carbon vapor deposition of benzene on Nomex-derived carbon fibers activated to two different burnoff degrees. Carbon molecular sieves with good selectivity for this separation and showing acceptable adsorption capacities were obtained from ACFs activated to the two burnoff degrees chosen. PMID:12702417

  13. The use of air separation in recycling CRT TV sets.

    PubMed

    Bedekovic, Gordan

    2015-04-01

    The aim of this paper is to examine the possibility of use of air separation in recycling CRT TV sets and determine the effect of operating variables of separators. Eight CRT TV sets were collected and after manual disassembly, parts of CRT TV sets were sorted into four fractions taking into account their properties. The subject of this research was the fraction consisting of yokes of a cathode tube, cables, connectors and wires. Testing samples were obtained by manual disassembly, shredding and sieving, after which the separation on the model of a cross-flow gravity air separator with horizontal flow was carried out. Four grain sizes, 4/2mm, 2/1mm, 1/0.5mm and -0.5mm, were tested on the separator. Testing was carried out according to the central composite design for three factors: splitter height, air velocity and feed position. The evaluation of results was carried out by the analysis of two parameters: concentrate grade and recovery. The obtained values of the concentrate grade varied from 45.9% for the smallest grain size of -0.5mm to 89.4% for the grain size of 1/0.5mm while recovery was very high, mostly over 99%. The highest increase of metal content in the concentrate of 21.1% was recorded for the smallest grain size of -0.5%. The Analysis of Variance showed that the splitter height and feed position have the strongest effect on the concentrate grade. PMID:25550215

  14. Means and method of detection in chemical separation procedures

    DOEpatents

    Yeung, Edward S.; Koutny, Lance B.; Hogan, Barry L.; Cheung, Chan K.; Ma, Yinfa

    1993-03-09

    A means and method for indirect detection of constituent components of a mixture separated in a chemical separation process. Fluorescing ions are distributed across the area in which separation of the mixture will occur to provide a generally uniform background fluorescence intensity. For example, the mixture is comprised of one or more charged analytes which displace fluorescing ions where its constituent components separate to. Fluorescing ions of the same charge as the charged analyte components cause a displacement. The displacement results in the location of the separated components having a reduced fluorescence intensity to the remainder of the background. Detection of the lower fluorescence intensity areas can be visually, by photographic means and methods, or by automated laser scanning.

  15. Means and method of detection in chemical separation procedures

    DOEpatents

    Yeung, E.S.; Koutny, L.B.; Hogan, B.L.; Cheung, C.K.; Yinfa Ma.

    1993-03-09

    A means and method are described for indirect detection of constituent components of a mixture separated in a chemical separation process. Fluorescing ions are distributed across the area in which separation of the mixture will occur to provide a generally uniform background fluorescence intensity. For example, the mixture is comprised of one or more charged analytes which displace fluorescing ions where its constituent components separate to. Fluorescing ions of the same charge as the charged analyte components cause a displacement. The displacement results in the location of the separated components having a reduced fluorescence intensity to the remainder of the background. Detection of the lower fluorescence intensity areas can be visually, by photographic means and methods, or by automated laser scanning.

  16. Separation methods and chemical and nutritional characteristics of tomato pomace

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato processing generates a large amount of pomace as a low value by-product primarily used as livestock feed or disposed. The objectives of this research were to investigate the chemical and nutritional characteristics and determine effective separation methods of peel and seed of commercial toma...

  17. Identification of heavy and superheavy nuclides using chemical separator systems

    NASA Astrophysics Data System (ADS)

    Türler, Andreas

    1999-11-01

    With the recent synthesis of superheavy nuclides produced in the reactions 48Ca+238U and 48Ca+242,244Pu, much longer-lived nuclei than the previously known neutron-deficient isotopes of the heaviest elements have been identified. Half-lives of several hours and up to several years have been predicted for the longest-lived isotopes of these elements. Thus, the sensitivity of radiochemical separation techniques may present a viable alternative to physical separator systems for the discovery of some of the predicted longer-lived heavy and superheavy nuclides. The advantages of chemical separator systems in comparison to kinematic separators lie in the possibility of using thick targets, high beam intensities spread over larger target areas and in providing access to nuclides emitted under large angles and low velocities. Thus, chemical separator systems are ideally suited to study also transfer and (HI, αxn) reaction products. In the following, a study of (HI, αxn) reactions will be presented and prospects to chemically identify heavy and superheavy elements discussed.

  18. Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine

    DOEpatents

    Moncelle, Michael E.

    2003-01-01

    An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

  19. Air-flow separation over unsteady breaking wind waves

    NASA Astrophysics Data System (ADS)

    Saxena, Gaurav

    2005-11-01

    In air-sea interaction processes, when considering wind stress over small-scale breaking waves, there are few direct quantitative experimental investigations into the role of air-flow separation on the interfacial momentum flux. Reul et. al, (1999), found multiple coherent patches of vorticity downwind of the crest that were strongly influenced by the geometric characteristics of the breaker. However, their breakers were generated by dispersive focusing techniques and, therefore, independent of the wind stress. We present experimental results obtained with particle image velocimetry (PIV) where moderate to strong winds directly generate unsteady small-scale breaking waves, a scenario commonly found in the open ocean. Particular attention has been devoted to capturing the spatio-temporal evolution of the air-water interface. Specifically, texture segmentation algorithms typically used for face recognition (Grey Level Co-occurrence Matrix (GLCM) and the Cross-Diagonal Texture Matrix (CDTM)) have been combined to yield robust and accurate estimates of the instantaneous breaker geometry.

  20. Advanced chemical separations in support of the clean option strategy

    SciTech Connect

    Horwitz, E.P.; Dietz, M.L.; Diamond, H.; Leonard, R.A.; Rogers, R.D.

    1993-09-01

    The objective of the Clean Option Strategy is to reduce the volume of waste from Hanford Storage tanks that must be vitrified and subsequently buried in a deep geologic repository to less than 1000 canisters (1) Advanced chemical separations in support of the Clean Option Strategy comprise a series of novel processes that are designed to extract and recover U, TRUs (Np, Pu, Am, Cm), {sup 90}Sr, {sup 99}Tc and {sup 137}Cs from dissolved sludge waste obtained from Hanford storage tanks. All inert constituents and the balance of the fission products, including barium and the lanthanides (Ln), will remain in the raffinates and effluent streams generated in these processes. The aim of the advanced chemical processes is to reduce the complexity and cost of the chemical pretreatment of the dissolved sludge from the single- and double-shelled tanks. To achieve this goal, Hanford must minimize the number of processes to extract U, TRUs, {sup 90}Sr, {sup 99}Tc and {sup 137}Cs, minimize the number of times that the initial volume of dissolved sludge must be handled, and concentrate product streams to reduce the scale of operation. To meet the requirements of advanced chemical separation processes, all systems must: Readily achieve the desired decontamination factors, have good chemical and radiolytic stability, not use highly hazardous substances, not significantly increase the volume of feed or waste and lend themselves to easy engineering scale-up.

  1. Use of exhaust gas as sweep flow to enhance air separation membrane performance

    DOEpatents

    Dutart, Charles H.; Choi, Cathy Y.

    2003-01-01

    An intake air separation system for an internal combustion engine is provided with purge gas or sweep flow on the permeate side of separation membranes in the air separation device. Exhaust gas from the engine is used as a purge gas flow, to increase oxygen flux in the separation device without increasing the nitrogen flux.

  2. Air-to-air view of STS-32 Columbia, OV-102, liftoff and SRB separation

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Air-to-air view of STS-32 Columbia, Orbiter Vehicle (OV) 102, shows solid rocket booster (SRB) separation. Leaving from Kennedy Space Center (KSC) Launch Complex (LC) Pad 39A at 7:34:59:98 am Eastern Standard Time (EST), OV-102 is backdropped against relatively clear Florida skies some 24 hours after dubious weather at the return-to-landing site (RTLS) had cancelled a scheduled launch. An exhaust plume trails behind OV-102. The photo was taken by astronaut Michael L. Coats, acting chief of the Astronaut Office, from the shuttle trainer aircraft (STA).

  3. Separation of the isotopes of boron by chemical exchange reactions

    DOEpatents

    McCandless, F.P.; Herbst, R.S.

    1995-05-30

    The isotopes of boron, {sup 10}B and {sup 11}B, are separated by means of a gas-liquid chemical exchange reaction involving the isotopic equilibrium between gaseous BF{sub 3} and a liquid BF{sub 3} donor molecular addition complex formed between BF{sub 3} gas and a donor chosen from the group consisting of: nitromethane, acetone, methyl isobutyl ketone, or diisobutyl ketone. 1 Fig.

  4. Separation of the isotopes of boron by chemical exchange reactions

    DOEpatents

    McCandless, Frank P.; Herbst, Ronald S.

    1995-01-01

    The isotopes of boron, .sup.10 B and .sup.11 B, are separated by means of a gas-liquid chemical exchange reaction involving the isotopic equilibrium between gaseous BF.sub.3 and a liquid BF.sub.3 . donor molecular addition complex formed between BF.sub.3 gas and a donor chosen from the group consisting of: nitromethane, acetone, methyl isobutyl ketone, or diisobutyl ketone.

  5. Use of Carbon Fiber Composite Molecular Sieves for Air Separation

    SciTech Connect

    Baker, Frederick S; Contescu, Cristian I; Gallego, Nidia C; Burchell, Timothy D

    2005-09-01

    A novel adsorbent material, 'carbon fiber composite molecular sieve' (CFCMS), has been developed by the Oak Ridge National Laboratory. Its features include high surface area, large pore volume, and a rigid, permeable carbon structure that exhibits significant electrical conductivity. The unique combination of high adsorptive capacity, permeability, good mechanical properties, and electrical conductivity represents an enabling technology for the development of novel gas separation and purification systems. In this context, it is proposed that a fast-cycle air separation process that exploits a kinetic separation of oxygen and nitrogen should be possible using a CFCMS material coupled with electrical swing adsorption (ESA). The adsorption of O{sub 2}, N{sub 2}, and CO{sub 2} on activated carbon fibers was investigated using static and dynamic techniques. Molecular sieving effects in the activated carbon fiber were highlighted by the adsorption of CO{sub 2}, a more sensitive probe molecule for the presence of microporosity in adsorbents. The kinetic studies revealed that O2 was more rapidly adsorbed on the carbon fiber than N{sub 2}, and with higher uptake under equilibrium conditions, providing the fiber contained a high proportion of very narrow micropores. The work indicated that CFCMS is capable of separating O{sub 2} and N{sub 2} from air on the basis of the different diffusion rates of the two molecules in the micropore network of the activated carbon fibers comprising the composite material. In response to recent enquires from several potential users of CFCMS materials, attention has been given to the development of a viable continuous process for the commercial production of CFCMS material. As part of this effort, work was implemented on characterizing the performance of lignin-based activated carbon fiber, a potentially lower cost fiber than the pitch-based fibers used for CFCMS production to date. Similarly, to address engineering issues, measurements were

  6. Air separation by integrally asymmetric hollow-fiber membranes

    SciTech Connect

    Feng, X.; Ivory, J.; Rajan, V.S.V.

    1999-10-01

    Integrally asymmetric hollow-fiber membranes each with an outer skin layer and a porous substrate were studied for air separation to produce nitrogen and oxygen enriched air. The test on both bore-side feed and shell-side feed with concurrent and countercurrent flow arrangements for a wide range of stage cuts shows that the bore-side feed countercurrent flow was the most advantageous configuration in the permeator design. When operated in the bore-side feed countercurrent configuration, the permeator performance compared favorably with the commercial systems available for nitrogen production. A mathematical model was developed for this configuration. Since the concentration polarization in the substrate was a major concern for the bore-side feed configuration, especially for high stage-cut operations, a theoretical approach was pursued to formulate the concentration polarization. This allows for the diagnosis of the significance of concentration polarization in a specific permeation process, although it is difficult to predict concentration polarization accurately due to limited knowledge of the detailed membrance structure.

  7. A Survey of Chemical Separation in Accreting Neutron Stars

    NASA Astrophysics Data System (ADS)

    Mckinven, Ryan; Cumming, Andrew; Medin, Zach; Schatz, Hendrik

    2016-06-01

    The heavy element ashes of rp-process hydrogen and helium burning in accreting neutron stars are compressed to high density where they freeze, forming the outer crust of the star. We calculate the chemical separation on freezing for a number of different nuclear mixtures resulting from a range of burning conditions for the rp-process. We confirm the generic result that light nuclei are preferentially retained in the liquid and heavy nuclei in the solid. This is in agreement with the previous study of a 17-component mixture of rp-process ashes by Horowitz et al., but extends that result to a much larger range of compositions. We also find an alternative phase separation regime for the lightest ash mixtures which does not demonstrate this generic behavior. With a few exceptions, we find that chemical separation reduces the expected {Q}{{imp}} in the outer crust compared to the initial rp-process ash, where {Q}{{imp}} measures the mean-square dispersion in atomic number Z of the nuclei in the mixture. We find that the fractional spread of Z plays a role in setting the amount of chemical separation and is strongly correlated to the divergence between the two/three-component approximations and the full component model. The contrast in Y e between the initial rp-process ashes and the equilibrium liquid composition is similar to that assumed in earlier two-component models of compositionally driven convection, except for very light compositions which produce nearly negligible convective driving. We discuss the implications of these results for observations of accreting neutron stars.

  8. Microwave separation of organic chemicals from mixed hazardous waste

    SciTech Connect

    Anderson, A.A.; Albano, R.K.

    1992-08-01

    The feasibility of utilizing the differential heating characteristics of microwave energy (MW) to aid in the chemical extraction and separation process of hazardous organic compounds from mixed hazardous waste, was studied at the INEL. The long-term objective of this work was to identify a practical method of separating or enhancing the separation process of organic hazardous waste components from mixed waste using microwave (MW) frequency radiation. Methods using MW energy for calcination, solidification, and drying of radioactive waste from nuclear facilities is becoming more attractive. In order to study the effectiveness of MW heating, samples of several organic chemicals simulating those which may be found at the Radioactive Waste Management Complex at the INEL were exposed to MW energy. Vapor collection and analysis was performed as a function of time, signal frequency, and MW power throughout the process. Signal frequencies ranging from 900 MHz t 8000 MHz were used. Although the signal frequency bandwidth of the selectivity was quite broad, for the material tested an indication of the frequency dependence in the selectivity of MW heating was given. Greater efficiency in terms of energy used and time required was observed. The relatively large electromagnetic field intensities generated at the resonant frequencies which were supported by the cavity sample holder demonstrated the use of cavity resonance to aid in the process of differential heating.

  9. Microwave separation of organic chemicals from mixed hazardous waste

    SciTech Connect

    Anderson, A.A.; Albano, R.K.

    1992-01-01

    The feasibility of utilizing the differential heating characteristics of microwave energy (MW) to aid in the chemical extraction and separation process of hazardous organic compounds from mixed hazardous waste, was studied at the INEL. The long-term objective of this work was to identify a practical method of separating or enhancing the separation process of organic hazardous waste components from mixed waste using microwave (MW) frequency radiation. Methods using MW energy for calcination, solidification, and drying of radioactive waste from nuclear facilities is becoming more attractive. In order to study the effectiveness of MW heating, samples of several organic chemicals simulating those which may be found at the Radioactive Waste Management Complex at the INEL were exposed to MW energy. Vapor collection and analysis was performed as a function of time, signal frequency, and MW power throughout the process. Signal frequencies ranging from 900 MHz t 8000 MHz were used. Although the signal frequency bandwidth of the selectivity was quite broad, for the material tested an indication of the frequency dependence in the selectivity of MW heating was given. Greater efficiency in terms of energy used and time required was observed. The relatively large electromagnetic field intensities generated at the resonant frequencies which were supported by the cavity sample holder demonstrated the use of cavity resonance to aid in the process of differential heating.

  10. Multi-layered, chemically bonded lithium-ion and lithium/air batteries

    SciTech Connect

    Narula, Chaitanya Kumar; Nanda, Jagjit; Bischoff, Brian L; Bhave, Ramesh R

    2014-05-13

    Disclosed are multilayer, porous, thin-layered lithium-ion batteries that include an inorganic separator as a thin layer that is chemically bonded to surfaces of positive and negative electrode layers. Thus, in such disclosed lithium-ion batteries, the electrodes and separator are made to form non-discrete (i.e., integral) thin layers. Also disclosed are methods of fabricating integrally connected, thin, multilayer lithium batteries including lithium-ion and lithium/air batteries.

  11. Effects of digestion, chemical separation, and deposition on Po-210 quantitative analysis

    SciTech Connect

    Seiner, Brienne N.; Morley, Shannon M.; Beacham, Tere A.; Haney, Morgan M.; Gregory, Stephanie J.; Metz, Lori A.

    2014-10-01

    Polonium-210 is a radioactive isotope often used to study sedimentation processes, food chains, aerosol behavior, and atmospheric circulations related to environmental sciences. Materials for the analysis of Po-210 range from tobacco leaves or cotton fibers, to soils and sediments. The purpose of this work was to determine polonium losses from a variety of sample types (soil, cotton fiber, and air filter) due to digestion technique, chemical separation, and deposition method for alpha energy analysis. Results demonstrated that yields from a perchloric acid wet-ash were similar to that from a microwave digestion. Both were greater than the dry-ash procedure. The polonium yield from the perchloric acid wet ash was 87 ± 5%, the microwave digestion had a yield of 100 ± 7%, and the dry ash had a yield of 38 ± 5%. The chemical separation of polonium by an anion exchange resin was used only on the soil samples due to the complex nature of this sample. The yield of Po-209 tracer after chemical separation and deposition for alpha analysis was 83 ± 7% for the soil samples. Spontaneous deposition yields for the cotton and air filters were 87 ± 4% and 92 ± 6%, respectively. Based on the overall process yields for each sample type the amount of Po-210 was quantified using alpha energy analysis. The soil contained 0.18 ± 0.08 Bq/g, the cotton swipe contained 0.7 mBq/g, and the air filter contained 0.04 ± 0.02 mBq/g. High and robust yields of polonium are possible using a suitable digestion, separation, and deposition method.

  12. The optimization air separation plants for combined cycle MHD-power plant applications

    NASA Technical Reports Server (NTRS)

    Juhasz, A. J.; Springmann, H.; Greenberg, R.

    1980-01-01

    Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

  13. Current status of ceramic-based membranes for oxygen separation from air.

    PubMed

    Hashim, Salwa Meredith; Mohamed, Abdul Rahman; Bhatia, Subhash

    2010-10-15

    There has been tremendous progress in membrane technology for gas separation, in particular oxygen separation from air in the last 20 years. It provides an alternative route to the existing conventional separation processes such as cryogenic distillation and pressure swing adsorption as well as cheaper production of oxygen with high purity. This review presents the recent advances of ceramic membranes for the separation of oxygen from air at high temperature. It covers the issues and problems with respect to the selectivity and separation performance. The paper also presents different approaches applied to overcome these challenges. The future directions of ceramic-based membranes for oxygen separation from air are also presented. PMID:20813344

  14. Composition and Thermodynamic Properties of Air in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Moeckel, W E; Weston, Kenneth C

    1958-01-01

    Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 degrees k and for pressures 10(-5) to 10 (plus 4) atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards.

  15. Age determination of single plutonium particles after chemical separation

    NASA Astrophysics Data System (ADS)

    Shinonaga, T.; Donohue, D.; Ciurapinski, A.; Klose, D.

    2009-01-01

    Age determination of single plutonium particles was demonstrated using five particles of the standard reference material, NBS 947 (Plutonium Isotopic Standard. National Bureau of Standards, Washington, D.C. 20234, August 19, 1982, currently distributed as NBL CRM-137) and the radioactive decay of 241Pu into 241Am. The elemental ratio of Am/Pu in Pu particles found on a carbon planchet was measured by wavelength dispersive X-ray spectrometry (WDX) coupled to a scanning electron microscope (SEM). After the WDX measurement, each plutonium particle, with an average size of a few μm, was picked up and relocated to a silicon wafer inside the SEM chamber using a micromanipulator. The silicon wafer was then transferred to a quartz tube for dissolution in an acid solution prior to chemical separation. After the Pu was chemically separated from Am and U, the isotopic ratios of Pu ( 240Pu/ 239Pu, 241Pu/ 239Pu and 242Pu/ 239Pu) were measured with a thermal ionization mass spectrometer (TIMS) for the calculation of Pu age. The age of particles determined in this study was in good agreement with the expected age (35.9 a) of NBS 947 within the measurement uncertainty.

  16. Integrated air separation plant-integrated gasification combined cycle power generator

    SciTech Connect

    Allam, R.J.; Topham, A.

    1992-01-21

    This patent describes an integrated gasification combined cycle power generation system, comprising an air separation unit wherein air is compressed, cooled, and separated into an oxygen and nitrogen enriched fractions, a gasification system for generating a fuel gas, an air compressor system for supplying compressed air for use in combusting the fuel gas, a combustion zone for effecting combustion of the compressed air and the fuel gas, and a gas turbine for effecting the generation of power from the resulting combusted gases from the combustion zone in the combined cycle power generation system. It comprises independently compressing feed air to the air separation unit to pressures of from 8 to 20 bar from the compressor system used to compress air for the combustion zone; cryogenically separating the air in the air separation unit having at least one distillation column operating at pressures of between 8 and 20 bar and producing an oxygen enriched fraction consisting of low purity oxygen, and; utilizing at least a portion of the low purity oxygen for effecting gasification of a carbon containing fuel source by partial oxidation in the gasification system and thereby generating a fuel gas stream; removing at least a portion of a nitrogen enriched fraction from the air separation unit and boosting its pressures to a pressure substantially equal to that of the fuel gas stream; and expanding at least another portion of the nitrogen enriched fraction in an expansion engine.

  17. Chemical separations by bubble-assisted interphase mass-transfer.

    PubMed

    Boyd, David A; Adleman, James R; Goodwin, David G; Psaltis, Demetri

    2008-04-01

    We show that when a small amount of heat is added close to a liquid-vapor interface of a captive gas bubble in a microchannel, interphase mass-transfer through the bubble can occur in a controlled manner with only a slight change in the temperature of the fluid. We demonstrate that this method, which we refer to as bubble-assisted interphase mass-transfer (BAIM), can be applied to interphase chemical separations, e.g., simple distillation, without the need for high temperatures, vacuum, or active cooling. Although any source of localized heating could be used, we illustrate BAIM with an all-optical technique that makes use of the plasmon resonance in an array of nanoscale metal structures that are incorporated into the channel to produce localized heating of the fluid when illuminated by a stationary low-power laser. PMID:18321130

  18. Radiolysis and hydrolysis of magnetically assisted chemical separation particles

    SciTech Connect

    Buchholz, B.A.; Nunez, L.; Vandegrift, G.F.

    1995-05-01

    The magnetically assisted chemical separation (MACS) process is designed to separate transuranic (TRU) elements out of high-level waste (HLW) or TRU waste. Magnetic microparticles (1--25 {mu}m) were coated with octyl (phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP) and tested for removing TRU elements from acidic nitrate solutions. The particles were contacted with nitric acid solutions and Hanford plutonium finishing plant (PFP) simulant, irradiated with a high intensity {sup 60}Co {gamma}-ray source, and evaluated for effectiveness in removing TRU elements from 2m HNO{sub 3} solutions. The resistance of the coatings and magnetic cores to radiolytic damage and hydrolytic degradation was investigated by irradiating samples of particles suspended in a variety of solutions with doses of up to 5 Mrad. Transmission electron microscopy (TEM), magnetic susceptibility measurements, and physical observations of the particles and suspension solutions were used to assess physical changes to the particles. Processes that affect the surface of the particles dramatically alter the binding sites for TRU in solution. Hydrolysis played a larger role than radiolysis in the degradation of the extraction capacity of the particles.

  19. Aerosol chemical components in Alaska air masses: 1. Aged pollution

    NASA Astrophysics Data System (ADS)

    Shaw, Glenn E.

    1991-12-01

    A 4-year Alaska chemical data set of aerosols or "dust" in the air clearly reveals a mixture of distinct aerosol components with different and interesting chemical composition, one or two being ascribed to pollution imported to Alaska by winds all the way from other continents. Of particular note is a strong chemical contrast between what we imagine to be highly scavenged, orographically lifted, northern Pacific air (Pacific marine air mass) and stagnant Arctic air (polar air mass), the latter containing seasonal average concentrations of between 2-4 times the concentration of the former, at least for pollution markers noncrustal vanadium, noncrustal manganese, arsenic, selenium, bromine, and antimony. The findings concur our old discovery that Arctic air is persistently polluted (Arctic haze), but Pacific air is relatively clean, in spite of the fact that Alaska is downwind of major pollution sources in the Orient. This is remarkable. In this the first of a two-part paper, we concentrate on the pollution component found primarily during incursion of Arctic polar air. Two major occurrences of visual haze with optical depths of approximately 0.2 and elevated aerosol concentration lasting about a month (spring 1985 and 1986) were affiliated with strong incoming transport of polar air, temperatures ranging from 10° to 20°C below normal (polar air) and air trajectory hindcasts leading back to industrial pollution sources in Eurasia. These long-range transport pollution events brought metal-rich aerosol of removal-resistant submicron particles. The size, chemistry, and meteorology all strongly suggest the presence of a well-aged (10-100 day) polluted air mass. An important implication is that in spring a large fraction of the Arctic polar air mass becomes charged with by-products of industrial pollution. In this multiyear chemical data set one finds a notable summer-winter contrast, changing by factors of 2 to 4 for pollution markers As, Se, Sb, and noncrustal

  20. Novel Molten Oxide Membrane for Ultrahigh Purity Oxygen Separation from Air.

    PubMed

    Belousov, Valery V; Kulbakin, Igor V; Fedorov, Sergey V; Klimashin, Anton A

    2016-08-31

    We present a novel solid/liquid Co3O4-36 wt % Bi2O3 composite that can be used as molten oxide membrane, MOM ( Belousov, V. V. Electrical and Mass Transport Processes in Molten Oxide Membranes. Ionics 22 , 2016 , 451 - 469 ), for ultrahigh purity oxygen separation from air. This membrane material consists of Co3O4 solid grains and intergranular liquid channels (mainly molten Bi2O3). The solid grains conduct electrons, and the intergranular liquid channels predominantly conduct oxygen ions. The liquid channels also provide the membrane material gas tightness and ductility. This last property allows us to deal successfully with the problem of thermal incompatibility. Oxygen and nitrogen permeation fluxes, oxygen ion transport number, and conductivity of the composite were measured by the gas flow, volumetric measurements of the faradaic efficiency, and four-probe dc techniques, accordingly. The membrane material showed the highest oxygen selectivity jO2/jN2 > 10(5) and sufficient oxygen permeability 2.5 × 10(-8) mol cm(-1) s(-1) at 850 °C. In the range of membrane thicknesses 1.5-3.3 mm, the oxygen permeation rate was controlled by chemical diffusion. The ease of the MOM fabrication, combined with superior oxygen selectivity and competitive oxygen permeability, shows the promise of the membrane material for ultrahigh purity oxygen separation from air. PMID:27482771

  1. Endocrine disrupting chemicals in indoor and outdoor air

    NASA Astrophysics Data System (ADS)

    Rudel, Ruthann A.; Perovich, Laura J.

    The past 50 years have seen rapid development of new building materials, furnishings, and consumer products and a corresponding explosion in new chemicals in the built environment. While exposure levels are largely undocumented, they are likely to have increased as a wider variety of chemicals came into use, people began spending more time indoors, and air exchange rates decreased to improve energy efficiency. As a result of weak regulatory requirements for chemical safety testing, only limited toxicity data are available for these chemicals. Over the past 15 years, some chemical classes commonly used in building materials, furnishings, and consumer products have been shown to be endocrine disrupting chemicals - that is they interfere with the action of endogenous hormones. These include PCBs, used in electrical equipment, caulking, paints and surface coatings; chlorinated and brominated flame retardants, used in electronics, furniture, and textiles; pesticides, used to control insects, weeds, and other pests in agriculture, lawn maintenance, and the built environment; phthalates, used in vinyl, plastics, fragrances, and other products; alkylphenols, used in detergents, pesticide formulations, and polystyrene plastics; and parabens, used to preserve products like lotions and sunscreens. This paper summarizes reported indoor and outdoor air concentrations, chemical use and sources, and toxicity data for each of these chemical classes. While industrial and transportation-related pollutants have been shown to migrate indoors from outdoor sources, it is expected that indoor sources predominate for these consumer product chemicals; and some studies have identified indoor sources as the predominant factor influencing outdoor ambient air concentrations in densely populated areas. Mechanisms of action, adverse effects, and dose-response relationships for many of these chemicals are poorly understood and no systematic screening of common chemicals for endocrine disrupting

  2. Endocrine disrupting chemicals in indoor and outdoor air

    PubMed Central

    Rudel, Ruthann A.; Perovich, Laura J.

    2009-01-01

    The past 50 years have seen rapid development of new building materials, furnishings, and consumer products and a corresponding explosion in new chemicals in the built environment. While exposure levels are largely undocumented, they are likely to have increased as a wider variety of chemicals came into use, people began spending more time indoors, and air exchange rates decreased to improve energy efficiency. As a result of weak regulatory requirements for chemical safety testing, only limited toxicity data are available for these chemicals. Over the past 15 years, some chemical classes commonly used in building materials, furnishings, and consumer products have been shown to be endocrine disrupting chemicals—that is they interfere with the action of endogenous hormones. These include PCBs, used in electrical equipment, caulking, paints and surface coatings; chlorinated and brominated flame retardants, used in electronics, furniture, and textiles; pesticides, used to control insects, weeds, and other pests in agriculture, lawn maintenance, and the built environment; phthalates, used in vinyl, plastics, fragrances, and other products; alkylphenols, used in detergents, pesticide formulations, and polystyrene plastics; and parabens, used to preserve products like lotions and sunscreens. This paper summarizes reported indoor and outdoor air concentrations, chemical use and sources, and toxicity data for each of these chemical classes. While industrial and transportation-related pollutants have been shown to migrate indoors from outdoor sources, it is expected that indoor sources predominate for these consumer product chemicals; and some studies have identified indoor sources as the predominant factor influencing outdoor ambient air concentrations in densely populated areas. Mechanisms of action, adverse effects, and dose-response relationships for many of these chemicals are poorly understood and no systematic screening of common chemicals for endocrine disrupting

  3. Bio-/Photo-Chemical Separation and Recovery of Uranium

    SciTech Connect

    Francis,A.J.; Dodge, C.J.

    2008-03-12

    Citric acid forms bidentate, tridentate, binuclear or polynuclear species with transition metals and actinides. Biodegradation of metal citrate complexes is influenced by the type of complex formed with metal ions. While bidentate complexes are readily biodegraded, tridentate, binuclear and polynuclear species are recalcitrant. Likewise certain transition metals and actinides are photochemically active in the presence of organic acids. Although the uranyl citrate complex is not biodegraded, in the presence of visible light it undergoes photochemical oxidation/reduction reactions which result in the precipitation of uranium as UO{sub 3} {center_dot} H{sub 2}O. Consequently, we developed a process where uranium is extracted from contaminated soils and wastes by citric acid. The citric-acid extract is subjected to biodegradation to recover the toxic metals, whereas uranyl citrate which is recalcitrant remains in solution. Photochemical degradation of the uranium citrate complex resulted in the precipitation of uranium. Thus the toxic metals and uranium in mixed waste are recovered in separate fractions for recycling or for disposal. The use of naturally-occurring compounds and the combined chemical and microbiological treatment process is more efficient than present methods and should result in considerable savings in cost.

  4. Chemical climatology of air pollutants at Pico Mountain Observatory

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Owen, R. C.; Perlinger, J. A.; Val Martin, M.; Fialho, P. J.; Mazzoleni, L. R.

    2013-12-01

    Pico Mountain Observatory (PMO) was established in 2001 on top of Pico Mountain (38.47°N, 28.40°W, 2,225 m a.s.l.) in the Azores Islands. PMO frequently samples free troposphere air over the Central North Atlantic. Long-range transport from neighboring continents impacts the concentration of air pollutants at PMO, but North American outflows have the most frequent influence due to predominantly westerly wind in mid-latitude regions of the Northern Hemisphere. This study summarizes observations of gases and aerosol since the station was established and combines transport patterns simulated by FLEXPART with observations to investigate chemical signatures of transport patterns. As the first step, FLEXPART backward retroplumes released from PMO will be created for the periods covered by our observation datasets. These results will be used to determine and classify sources of the transported air for long time periods. Seasonal variations in sources and transport pathways will be examined. This information is critical to understand variations in air pollutant observations at PMO, because sources and transport trajectories define age and composition of air plumes that arrive at PMO. In the second step, transport associated with certain chemical signatures, e.g., elevated ozone combined with depressed CO, will be extracted, and transport patterns will be identified for each classified chemical signature. The analysis will reveal correlations between transport patterns and elevation of air pollutants at PMO, which will help to understand measurement datasets of multiple air pollutants. Impacts of anthropogenic and biomass burning emissions on CO concentration at PMO will also be determined through multiplying retroplumes with emission inventories. Long-term trends in impacts from both sources will be examined to find potential correlations with recently implemented air quality regulations, occurrence of wildfires, and global climate change.

  5. Water Tank with Capillary Air/Liquid Separation

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.

    2010-01-01

    A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

  6. International Space Station Common Cabin Air Assembly Water Separator On-Orbit Operation, Failure, and Redesign

    NASA Technical Reports Server (NTRS)

    Balistreri, Steven F., Jr.; Shaw, Laura A.; Laliberte, Yvon

    2010-01-01

    The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The Water Separator (WS) pulls in air and water from the CHX, and centrifugally separates the mixture, sending the water to the condensate bus and the air back into the CHX outlet airstream. Two distinct early failures of the CCAA Water Separator in the Quest Airlock forced operational changes and brought about the re-design of the Water Separator to improve the useful life via modification kits. The on-orbit operational environment of the Airlock presented challenges that were not foreseen with the original design of the Water Separator. Operational changes were instituted to prolong the life of the third installed WS, while waiting for newly designed Water Separators to be delivered on-orbit. The modification kit design involved several different components of the Water Separator, including the innovative use of a fabrication technique to build the impellers used in Water Separators out of titanium instead of aluminum. The technique allowed for the cost effective production of the low quantity build. This paper will describe the failures of the Water Separators in the Quest Airlock, the operational constraints that were implemented to prolong the life of the installed Water Separators throughout the USOS, and the innovative re-design of the CCAA Water Separator.

  7. The transfer of carbon fibers through a commercial aircraft water separator and air cleaner

    NASA Technical Reports Server (NTRS)

    Meyers, J. A.

    1979-01-01

    The fraction of carbon fibers passing through a water separator and an air filter was determined in order to estimate the proportion of fibers outside a closed aircraft that are transmitted to the electronics through the air conditioning system. When both devices were used together and only fibers 3 mm or larger were considered, a transfer function of .001 was obtained.

  8. Optimum design of bipolar plates for separate air flow cooling system of PEM fuel cells stacks

    NASA Astrophysics Data System (ADS)

    Franco, Alessandro

    2015-12-01

    The paper discusses about thermal management of PEM fuel cells. The objective is to define criteria and guidelines for the design of the air flow cooling system of fuel cells stacks for different combination of power density, bipolar plates material, air flow rate, operating temperature It is shown that the optimization of the geometry of the channel permits interesting margins for maintaining the use of separate air flow cooling systems for high power density PEM fuel cells.

  9. Materials and methods for the separation of oxygen from air

    DOEpatents

    MacKay, Richard; Schwartz, Michael; Sammells, Anthony F.

    2003-07-15

    Metal oxides particularly useful for the manufacture of catalytic membranes for gas-phase oxygen separation processes having the formula: O.sub.5+z where: x and x' are greater than 0; y and y' are greater than 0; x+x' is equal to 2; y+y' is less than or equal to 2; z is a number that makes the metal oxide charge neutral; A is an element selected from the lanthanide elements; A' is an element selected from Be, Mg, Ca, Sr, Ba and Ra; A" is an element selected from the f block lanthanides, Be, Mg, Ca, Sr, Ba and Ra; B is an element selected from the group consisting of Al, Ga, In or mixtures thereof and B" is Co or Mg, with the exception that when B" is Mg, A' and A" are not Mg. The metal oxides are useful for preparation of dense membranes which may be formed from dense thin films of the mixed metal oxide on a porous metal oxide element. The invention also provides methods and catalytic reactors for oxygen separation and oxygen enrichment of oxygen deficient gases which employ mixed conducting metal oxides of the above formula.

  10. STS-32 OV-102 air revitalization system (ARS) humidity separator problem

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During STS-32, onboard Columbia, Orbiter Vehicle (OV) 102, a leakage problem at environmental control and life support system (ECLSS) air revitalization system (ARS) humidity separator A below the middeck is solved with a plastic bag and a towel. The towel inserted inside a plastic bag absorbed the water that had collected at the separator inlet.

  11. Honeywell's organic air vehicle chemical-biological sensing platform

    NASA Astrophysics Data System (ADS)

    Cole, Barry E.; Krafthefer, Brian; Knee, Daniel; Fulton, Vaughn M.; Law, Kristen

    2004-12-01

    Unmanned air vehicles (UAVs) today are mostly used for reconnaissance and sometimes weapons delivery. Remote sensing of chemical-biological (CB) agents is another beneficial use of UAVs. While remote sensing of CB agents can be done by LIDAR spectroscopy, this technology is less spatially precise and less sensitive than actual measurements on a collected sample. One family of UAVs of particularly unique benefit for CB sampling and in-flight analysis is the Honeywell family of Organic Air Vehicles (OAVs). This vehicle with its ability to hover and stare has the unique ability among UAVs to collect and analyze chem-bio samples from a specific location over extended periods of time. Such collections are not possible with other micro-air-vehicles (MAVs) that only operate in fly-by mode. This paper describes some of the Honeywell OAV features that are conducive to CB detection.

  12. Martian Air Separation for In-Situ Resource Utilization Processes

    NASA Astrophysics Data System (ADS)

    MacArthur, J. R.; Way, J. D.; Baldwin, R. M.; Mason, L. W.

    2002-01-01

    We will introduce the concept of using synthetic organic and inorganic membranes for the separation and purification of carbon dioxide (CO2) from mixtures of gases, such as those found in the Martian atmosphere. The class of applications targeted in this project are known as In Situ Resource Utilization (ISRU). ISRU involves the use of resources present on Mars, such as atmospheric gases, a concept that will dramatically reduce the amount of material that must be transferred from Earth to support a mission. ISRU technologies will provide many of the consumables required for a manned mission, such as rocket propellant, water, oxygen and buffer gases. The Martian atmosphere is primarily CO2, and also contains a few percent nitrogen and argon. Martian CO2 is a principal component of several ISRU processes that may be used in a manned Mars mission. For example, the Sabatier/Electrolysis (SE) process reacts atmospheric CO2 with hydrogen to produce methane (fuel), water, and oxygen. Pure gas and mixed gas permeation tests with CO2, Ar, N2, and O2 were performed over the temperature range 243 K to 295 K with a several candidate membrane materials including rubbery polymers (silicone rubber and PEBAX) and supported faujasite zeolite membranes. In experiments with commercially available silicone rubber membranes, the pure gas CO2 permeance (flux/driving force) increases from 460 GPUs to 655 GPUs as the temperature decreases from 295 K to 243 K. A GPU is a commonly used unit of permeance and is defined as 10-6 cm3(STP)/cm2-s-cm Hg. The ideal carbon dioxide/nitrogen separation factor (ratio of pure gas permeances) increases from 7.5 to 17.5 over the same temperature range. However, in mixed gas experiments, the CO2/N2 separation factor was much lower, increasing from 4.5 to 6 as the temperature decreased from 295 K to 243 K. This difference was attributed to plasticization of the rubbery polymer membrane by CO2.

  13. In-forest canopy chemical sinks and regional air quality

    NASA Astrophysics Data System (ADS)

    Fuentes, J. D.; Brune, W. H.; Stockwell, W. R.

    2009-12-01

    In forested landscapes, it is necessary to estimate emissions of biogenic hydrocarbons emitted by vegetation. Such emissions are required to determine the contribution of biogenic hydrocarbons to the formation of oxidants such as ozone and secondary organic aerosols. Depending on forest architecture (e.g., leaf area index) and lifetime of chemical species, substantial biogenic hydrocarbons can react within plant canopies before reaching the surrounding atmosphere. Emission inventories are required for regional air quality models designed to estimate oxidant and aerosol production from biogenic hydrocarbons. Also, emission inventories for air quality models need to account for reductions of biogenic hydrocarbons and increases in their products due to reactions within plant canopies. Therefore, one objective of this presentation is to report and discuss results on the degree of chemical processing for a select group of biogenic hydrocarbon species as a function of forest canopy attributes and prevailing atmospheric turbulence. Chemical processing within plant canopies can appropriately be estimated using one-dimensional models that include detailed photochemical mechanisms, and radiative transfer and atmospheric turbulence theory within plant canopies. Due to computational demands, such detailed canopy models cannot be realistically included in regional models. Thus, a second goal of this research is to develop a simplified algorithm to account for the in-plant canopy chemical reactions leading to reductions in the estimated biogenic hydrocarbon emissions. The purpose of this new algorithm is to include an explicit representation of the biogenic hydrocarbon chemical sinks in regional air quality models. Model outputs will contrast results obtained for cases with and without in-plant canopy chemical processing in an effort to quantify the effect of chemical sinks on regional oxidant formation. Also, the presentation will highlight the effects of in-plant canopy

  14. Air separation and oxygen storage properties of hexagonal rare-earth manganites

    NASA Astrophysics Data System (ADS)

    Abughayada, Castro

    This dissertation presents evaluation results of hexagonal Y1-x RxMnO3+delta (R = Er, Y, Dy, Pr, La, Tb and Ho) rare-earth manganites for prospective air separation applications. In these materials, oxygen content is sensitively dependent on the surrounding conditions of temperature and/or oxygen partial pressure, and therefore they exhibit the ability to selectively absorb, store, and release significant amounts of separated oxygen from air. This study presents a full characterization of their thermogravimetric characteristics and air separation capabilities. With the expected potential impact of oxygen content on the physical properties of these materials, the scope of this work is expanded to explore other relevant properties such as magnetic, transport, and dilatometric characteristics. Single-phase polycrystalline samples of these materials were achieved in the hexagonal P63cm phase through solid state reaction at elevated temperatures. Further annealings under reducing conditions were required for samples with large rare-earth cations in order to suppress the competing perovskite structure and form in the anticipated hexagonal phase. Thermogravimetric measurements in oxygen atmospheres demonstrated that samples with the larger R ionic radii show rapid and reversible incorporation of significant amounts of excess oxygen (0.41 > delta > 0) at an unusual low temperature range ~190-325 °C. The reversible oxygen storage characteristics of HoMnO3+delta and related materials shown by the fast incorporation and release of interstitial oxygen at easily accessible elevated temperatures of ~300 °C demonstrate the feasibility and potential for low-cost thermal swing adsorption TSA process for oxygen separation and enrichment from air. Neutron and X-ray powder diffraction measurements confirmed the presence of three line compounds RMnO3+delta, the oxygen stoichiometric P6 3cm (delta = 0 for all R), the intermediate oxygen content superstructure phase R3c (delta ~ 0

  15. CHEMICAL REMOVAL OF BIOMASS FROM WASTE AIR BIOTRICKLING FILTERS: SCREENING CHEMICALS OF POTENTIAL INTEREST. (R825392)

    EPA Science Inventory

    A protocol was developed to rapidly assess the efficiency of chemical washing for the removal of excess biomass from biotrickling filters for waste air treatment. Although the experiment was performed on a small scale, conditions were chosen to simulate application in full-scale ...

  16. Experimental investigation on performance of ice storage air-conditioning system with separate heat pipe

    SciTech Connect

    Fang, Guiyin; Liu, Xu; Wu, Shuangmao

    2009-11-15

    An experimental study on operation performance of ice storage air-conditioning system with separate helical heat pipe is conducted in this paper. The experimental system of ice storage air-conditioning system with separate heat pipe is set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the COP (coefficient of performance) of the system, the IPF (ice packing factor) and the cool storage capacity in the cool storage tank during charging period, and the cool discharge rate and the cool discharge capacity in the cool storage tank, the outlet water temperature in the cool storage tank and the outlet air temperature in room unit during discharging period are investigated. The experimental results show that the ice storage air-conditioning system with separate helical heat pipe can stably work during charging and discharging period. This indicates that the ice storage air-conditioning system with separate helical heat pipe is well adapted to cool storage air-conditioning systems in building. (author)

  17. 40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.655 Chemical balances of fuel, intake air, and exhaust. (a) General. Chemical balances of fuel, intake air, and... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Chemical balances of fuel, intake...

  18. 40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.655 Chemical balances of fuel, intake air, and exhaust. (a) General. Chemical balances of fuel, intake air, and... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Chemical balances of fuel, intake...

  19. 40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.655 Chemical balances of fuel, intake air, and exhaust. (a) General. Chemical balances of fuel, intake air, and... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Chemical balances of fuel, intake...

  20. 40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.655 Chemical balances of fuel, intake air, and exhaust. (a) General. Chemical balances of fuel, intake air, and... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Chemical balances of fuel, intake...

  1. 40 CFR 1065.655 - Chemical balances of fuel, intake air, and exhaust.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.655 Chemical balances of fuel, intake air, and exhaust. (a) General. Chemical balances of fuel, intake air, and... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Chemical balances of fuel, intake...

  2. Multi-element analysis of manganese nodules by atomic absorption spectrometry without chemical separation

    USGS Publications Warehouse

    Kane, J.S.; Harnly, J.M.

    1982-01-01

    Five manganese nodules, including the USGS reference nodules A-1 and P-1, were analyzed for Co, Cu, Fe, K, Mg, Mn, Na, Ni and Zn without prior chemical separation by using a simultaneous multi-element atomic absorption spectrometer with an air-cetylene flame. The nodules were prepared in three digestion matrices. One of these solutions was measured using sixteen different combinations of burner height and air/acetylene ratios. Results for A-1 and P-1 are compared to recommended values and results for all nodules are compared to those obtained with an inductively coupled plasma. The elements Co, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn are simultaneously determined with a composite recovery for all elements of 100 ?? 7%, independent of the digestion matrices, heights in the flame, or flame stoichiometries examined. Individual recoveries for Co, K, and Ni are considerably poorer in two digests than this composite figure, however. The optimum individual recoveries of 100 ?? 5% and imprecisions of 1-4%, except for zinc, are obtained when Co, K, Mn, Na and Ni are determined simultaneously in a concentrated digest, and in another analytical sequence, when Cu, Fe, Mg, Mn and Zn are measured simultaneously after dilution. Determination of manganese is equally accurate in the two sequences; its measurement in both assures internal consistency between the two measurement sequences. This approach improves analytical efficiency over that for conventional atomic absorption methods, while minimizing loss of accuracy or precision for individual elements. ?? 1982.

  3. Chemical evaluation of non-woven nylon separators used in Ni/Cd cells

    NASA Technical Reports Server (NTRS)

    Cuddihy, Edward F.

    1991-01-01

    The goals of the chemical analysis was to identify Gates 2505 degradation mechanism, to determine if Eagle-Pitcher 2505 supply suitable for flight, and to assess the 2538 as a candidate replacement, based on chemical findings. Chemical testing strongly indicates that the Gates 2505 stored in Florida had undergone partial chemical deterioration, believed caused by exposure to high humidities and temperature. A suspected role of zinc chloride as a separator concern during storage was not verified in this study (the effect of ZnCl2 on cell/electrode performance was not addressed). No substantial chemical issues or concerns with using EP 2505 as Ni/Cd battery separator for Mars Observer and TOPEX could be found. No chemical issues or concerns with using 2538 as Ni/Cd battery separator were found, in fact, chemical evidence suggest that 2538 may be a better material, as compared to 2505.

  4. Influence of air-jet vortex generator diameter on separation region

    NASA Astrophysics Data System (ADS)

    Szwaba, Ryszard

    2013-08-01

    Control of shock wave and boundary layer interaction continues to attract a lot of attention. In recent decades several methods of interaction control have been investigated. The research has mostly concerned solid (vane type) vortex generators and transpiration methods of suction and blowing. This investigation concerns interaction control using air-jets to generate streamwise vortices. The effectiveness of air-jet vortex generators in controlling separation has been proved in a previous research. The present paper focuses on the influence of the vortex generator diameter on the separation region. It presents the results of experimental investigations and provides new guidelines for the design of air-jet vortex generators to obtain more effective separation control.

  5. Simulation of a Novel Single-column Cryogenic Air Separation Process Using LNG Cold Energy

    NASA Astrophysics Data System (ADS)

    Jieyu, Zheng; Yanzhong, Li; Guangpeng, Li; Biao, Si

    In this paper, a novel single-column air separation process is proposed with the implementation of heat pump technique and introduction of LNG coldenergy. The proposed process is verifiedand optimized through simulation on the Aspen Hysys® platform. Simulation results reveal that thepower consumption per unit mass of liquid productis around 0.218 kWh/kg, and the total exergy efficiency of the systemis 0.575. According to the latest literatures, an energy saving of 39.1% is achieved compared with those using conventional double-column air separation units.The introduction of LNG cold energy is an effective way to increase the system efficiency.

  6. Pilot and Controller Evaluations of Separation Function Allocation in Air Traffic Management

    NASA Technical Reports Server (NTRS)

    Wing, David; Prevot, Thomas; Morey, Susan; Lewis, Timothy; Martin, Lynne; Johnson, Sally; Cabrall, Christopher; Como, Sean; Homola, Jeffrey; Sheth-Chandra, Manasi; Mercer, Joey

    2013-01-01

    Two human-in-the-loop simulation experiments were conducted in coordinated fashion to investigate the allocation of separation assurance functions between ground and air and between humans and automation. The experiments modeled a mixed-operations concept in which aircraft receiving ground-based separation services shared the airspace with aircraft providing their own separation service (i.e., self-separation). Ground-based separation was provided by air traffic controllers without automation tools, with tools, or by ground-based automation with controllers in a managing role. Airborne self-separation was provided by airline pilots using self-separation automation enabled by airborne surveillance technology. The two experiments, one pilot-focused and the other controller-focused, addressed selected key issues of mixed operations, assuming the starting point of current-day operations and modeling an emergence of NextGen technologies and procedures. In the controller-focused experiment, the impact of mixed operations on controller performance was assessed at four stages of NextGen implementation. In the pilot-focused experiment, the limits to which pilots with automation tools could take full responsibility for separation from ground-controlled aircraft were tested. Results indicate that the presence of self-separating aircraft had little impact on the controllers' ability to provide separation services for ground-controlled aircraft. Overall performance was best in the most automated environment in which all aircraft were data communications equipped, ground-based separation was highly automated, and self-separating aircraft had access to trajectory intent information for all aircraft. In this environment, safe, efficient, and highly acceptable operations could be achieved for twice today's peak airspace throughput. In less automated environments, reduced trajectory intent exchange and manual air traffic control limited the safely achievable airspace throughput and

  7. STS-32 OV-102 air revitalization system (ARS) humidity separator problem

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During STS-32, onboard Columbia, Orbiter Vehicle (OV) 102, a leakage problem at environmental control and life support system (ECLSS) air revitalization system (ARS) humidity separator A below the middeck is documented in this closeup view. Note the many bubbles around the separator. The crew cleared out stowage bags, lithium hydroxide (LiOH) cannisters and other materials to get at the problem. It was eventually repaired.

  8. Laser-machined components for microanalytical and chemical separation devices

    NASA Astrophysics Data System (ADS)

    Matson, Dean W.; Martin, Peter M.; Bennett, Wendy D.

    1998-10-01

    Excimer lasers have proven to be powerful tools for machining polymeric components used in microanalytical and microchemical separation devices. We report the use of laser machining methods to produce microfluidic channels and liquid/liquid contact membranes for a number of devices fabricated at our laboratory. Microchannels 50- to 100- micrometers -wide have been produced directly in bulk polycarbonate chips using a direct-write laser micromachining system. Wider microchannels have been produced by laser machining paths through sheets of polyimide film, then sandwiching the patterned piece between solid chips of polycarbonate stock. A comparison of direct-write and mask machining processes used to produce some of the microfluidic features is made. Examples of microanalytical devices produced using these methods are presented. Included are microdialysis units used to remove electrolytes from liquid samples and electrophoretic separation devices, both used for extremely low volume samples intended for mass spectrometric analysis. A multilayered microfluidic device designed to analyze low volume groundwater samples for hazardous metals and a fluidics motherboard are also described. Laser machining processes have also been explored for producing polymeric membranes suitable for use in liquid/liquid contactors used for removal of soluble hazardous components from waste streams. A step-and-repeat mask machining process was used to produce 0.5 X 8 cm membranes in 25- and 50-micrometers -thick polyimide. Pore diameters produced using this method were five and ten micrometers. The laser machined membranes were sputter coated with PTFE prior to use to improve fluid breakthrough characteristics.

  9. A Belief-Based Model of Air Traffic Controllers Performing Separation Assurance

    NASA Technical Reports Server (NTRS)

    Landry, S.J.

    2009-01-01

    A model of an air traffic controller performing a separation assurance task was produced. The model was designed to be simple to use and deploy in a simulator, but still provide realistic behavior. The model is based upon an evaluation of the safety function of the controller for separation assurance, and utilizes fast and frugal heuristics and belief networks to establish a knowledge set for the controller model. Based on this knowledge set, the controller acts to keep aircraft separated. Validation results are provided to demonstrate the model s performance.

  10. Rheological monitoring of phase separation induced by chemical reaction in thermoplastic-modified epoxy

    SciTech Connect

    Vinh-Tung, C.; Lachenal, G.; Chabert, B.

    1996-12-31

    The phase separation induced by chemical reaction in blends of tetraglycidyl-diaminodiphenylmethane epoxy resin with an aromatic diamine hardener and a thermoplastic was monitored. Rheological measurements and morphologies are described.

  11. Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

    SciTech Connect

    Rudd, A.; Prahl, D.

    2014-12-01

    IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are (1) the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and (2) the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

  12. Duct System Flammability and Air Sealing Fire Separation Assemblies in the International Residential Code

    SciTech Connect

    Rudd, A.; Prahl, D.

    2014-12-01

    IBACOS identified two barriers that limit the ability of builders to cost-effectively achieve higher energy efficiency levels in housing. These are the use of duct system materials that inherently achieve airtightness and are appropriately sized for low-load houses and the ability to air seal fire separation assemblies. The issues identified fall into a gray area of the codes.

  13. Separation and Quantification of Chemically Diverse Analytes in Neutron Irradiated Fissile Materials

    SciTech Connect

    Douglas, Matthew; Friese, Judah I.; Greenwood, Lawrence R.; Farmer, Orville T.; Thomas, Linda MP; Maiti, Tapas C.; Finn, Erin C.; Garofoli, Stephanie J.; Gassman, Paul L.; Huff, Morgan M.; Schulte, Shannon M.; Smith, Steven C.; Thomas, Kathie K.; Bachelor, Paula P.

    2009-10-01

    Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of interest for applications in environmental monitoring, nuclear waste management, and national security. To overcome mass and spectral interferences, and the relative small quantities of some target analytes, an extensive series of chemical separations is necessary. Based on established separations processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have been evaluating and optimizing a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. For simplicity, much of the chemical separation development work has been performed using stable elements as surrogates for the radioactive material. We have recently evaluated the optimized procedures using an irradiated sample to examine the adequacy of separations for measurement of desired analytes by gamma spectrometry. Here we present the results of this evaluation and describe the radiochemical separations utilized.

  14. Chemical oxidation of endohedral metallofullerenes: identification and separation of distinct classes.

    PubMed

    Bolskar, Robert D; Alford, J Michael

    2003-06-01

    Chemical oxidation is useful for solubilizing and separating endohedral metallofullerenes, as demonstrated here by a separation of three categories of Gd@C2n species and by the solubilization of Tm@C60+ and Tm@C70+ for the first time. PMID:12809236

  15. Temporal variations of cathode performance in air-cathode single-chamber microbial fuel cells with different separators

    NASA Astrophysics Data System (ADS)

    Ma, Jinxing; Wang, Zhiwei; Suor, Denis; Liu, Shumeng; Li, Jiaqi; Wu, Zhichao

    2014-12-01

    An ideal separator is essential for efficient power production from air-cathode single-chamber microbial fuel cells (MFCs). In this study, we use different kinds of membranes as separators, including Nafion 117 proton exchange membrane, polyethersulfone and poly(vinylidene fluoride) microfiltration membranes. Temporal variations of cathode performance are monitored during the experiment. Results show that MFCs with microfiltration membranes present higher power output but deterioration is still observed after about 600-h operation. With the utilization of appropriate separators (e.g., polyethersulfone membrane), biofouling, cation fouling and chemical scale fouling of the cathodes are alleviated while reaction fouling seems inevitable. Moreover, it is found that Coulombic efficiency (CE) and energy efficiency (EE) are also related to the cathode performance. Despite relatively high oxygen diffusivity (1.49 × 10-5 cm2 s-1), CE and EE of the MFC with 0.1 μm pore-size polyethersulfone membrane can reach 92.8% and 13.7%, respectively, when its average power density registers 403.5 mW m-2. This phenomenon might be attributed to the finding that the overall substrate consumption rate due to oxygen reduction and respiration is almost constant in the air-cathode MFCs. Oxygen leakage into the electrolyte can be inhibited due to the efficient oxygen reduction reaction on the surface of the cathode.

  16. “Impact of CB6 and CB05TU chemical mechanisms on air quality”

    EPA Science Inventory

    “Impacts of CB6 and CB05TU chemical mechanisms on air quality”In this study, we incorporate the newly developed Carbon Bond chemical mechanism (CB6) into the Community Multiscale Air Quality modeling system (CMAQv5.0.1) and perform air quality model simulations with the CB6 and t...

  17. Quantitative Characterizations of Ultrashort Echo (UTE) Images for Supporting Air-Bone Separation in the Head

    PubMed Central

    Hsu, Shu-Hui; Cao, Yue; Lawrence, Theodore S.; Tsien, Christina; Feng, Mary; Grodzki, David M.; Balter, James M.

    2015-01-01

    Accurate separation of air and bone is critical for creating synthetic CT from MRI to support Radiation Oncology workflow. This study compares two different ultrashort echo-time sequences in the separation of air from bone, and evaluates post-processing methods that correct intensity nonuniformity of images and account for intensity gradients at tissue boundaries to improve this discriminatory power. CT and MRI scans were acquired on 12 patients under an institution review board-approved prospective protocol. The two MRI sequences tested were ultra-short TE imaging using 3D radial acquisition (UTE), and using pointwise encoding time reduction with radial acquisition (PETRA). Gradient nonlinearity correction was applied to both MR image volumes after acquisition. MRI intensity nonuniformity was corrected by vendor-provided normalization methods, and then further corrected using the N4itk algorithm. To overcome the intensity-gradient at air-tissue boundaries, spatial dilations, from 0 to 4 mm, were applied to threshold-defined air regions from MR images. Receiver operating characteristic (ROC) analyses, by comparing predicted (defined by MR images) versus “true” regions of air and bone (defined by CT images), were performed with and without residual bias field correction and local spatial expansion. The post-processing corrections increased the areas under the ROC curves (AUC) from 0.944 ± 0.012 to 0.976 ± 0.003 for UTE images, and from 0.850 ± 0.022 to 0.887 ± 0.012 for PETRA images, compared to without corrections. When expanding the threshold-defined air volumes, as expected, sensitivity of air identification decreased with an increase in specificity of bone discrimination, but in a non-linear fashion. A 1-mm air mask expansion yielded AUC increases of 1% and 4% for UTE and PETRA images, respectively. UTE images had significantly greater discriminatory power in separating air from bone than PETRA images. Post-processing strategies improved the

  18. Quantitative characterizations of ultrashort echo (UTE) images for supporting air-bone separation in the head

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Hui; Cao, Yue; Lawrence, Theodore S.; Tsien, Christina; Feng, Mary; Grodzki, David M.; Balter, James M.

    2015-04-01

    Accurate separation of air and bone is critical for creating synthetic CT from MRI to support Radiation Oncology workflow. This study compares two different ultrashort echo-time sequences in the separation of air from bone, and evaluates post-processing methods that correct intensity nonuniformity of images and account for intensity gradients at tissue boundaries to improve this discriminatory power. CT and MRI scans were acquired on 12 patients under an institution review board-approved prospective protocol. The two MRI sequences tested were ultra-short TE imaging using 3D radial acquisition (UTE), and using pointwise encoding time reduction with radial acquisition (PETRA). Gradient nonlinearity correction was applied to both MR image volumes after acquisition. MRI intensity nonuniformity was corrected by vendor-provided normalization methods, and then further corrected using the N4itk algorithm. To overcome the intensity-gradient at air-tissue boundaries, spatial dilations, from 0 to 4 mm, were applied to threshold-defined air regions from MR images. Receiver operating characteristic (ROC) analyses, by comparing predicted (defined by MR images) versus ‘true’ regions of air and bone (defined by CT images), were performed with and without residual bias field correction and local spatial expansion. The post-processing corrections increased the areas under the ROC curves (AUC) from 0.944 ± 0.012 to 0.976 ± 0.003 for UTE images, and from 0.850 ± 0.022 to 0.887 ± 0.012 for PETRA images, compared to without corrections. When expanding the threshold-defined air volumes, as expected, sensitivity of air identification decreased with an increase in specificity of bone discrimination, but in a non-linear fashion. A 1 mm air mask expansion yielded AUC increases of 1 and 4% for UTE and PETRA images, respectively. UTE images had significantly greater discriminatory power in separating air from bone than PETRA images. Post-processing strategies improved the

  19. Enhanced separation of water quality parameters in the DAF (Dissolved Air Flotation) system using ozone.

    PubMed

    Lee, Byoung-Ho; Song, Won-Chul; Kim, Hye-Young; Kim, Jeong-Hyeon

    2007-01-01

    Dissolved Air Flotation (DAF) has been used in water and wastewater treatment because it has an excellent separation capability. It was found that the separation capability of the DAF system could be even more enhanced by ozone. Ozone was applied as a substitute for air in the DAF system, so that the system was named as the DOF (Dissolved Ozone Flotation) system. Ozone not only enhances coagulation as is well known, but also provides larger micro-bubble volume because the solubility of ozone in water is much higher than that of air. Ozone enhanced the separation rate of SS by 13.6%, and turbidity by 21% in the DOF system compared to the DAF system. T-P was also removed 7.7% more in the DOF system. 41.5% of color and 7.4% of COD(Cr) were enhanced in their removal rate. Coliform and heterotrophic bacteria were removed 54% and 57.3% more in the DOF system. Separation capability of the DOF system was greatly enhanced for most of the water quality parameters because ozone provides strong oxidation power with large volume of micro-bubbles. PMID:18048988

  20. Combined air stripper/membrane vapor separation systems. [Volatile organic compounds

    SciTech Connect

    Wijmans, J.G.; Baker, R.W.; Kamaruddin, H.D.; Kaschemekat, J.; Olsen, R.P.; Rose, M.E.; Segelke, S.V.

    1992-11-01

    Air stripping is an economical and efficient method of removing dissolved volatile organic compounds (VOCs) from contaminated groundwater. Air strippers, however, produce a vent air stream, which must meet the local air quality limits. If the VOC content exceeds the limits, direct discharge is not possible; therefore, a carbon adsorption VOC capture system is used to treat the vent air. This treatment step adds a cost of at least $50/lb of VOC captured. In this program, a combined air stripper/membrane vapor separation system was constructed and demonstrated in the laboratory. The membrane system captures VOCs from the stripper vent stream at a projected cost of $15/lb VOC for a water VOC content of 5 ppmw, and $75/lb VOC for a water VOC content of 1 ppmw. The VOCs are recovered as a small, concentrated liquid fraction for disposal or solvent recycling. The concept has been demonstrated in experiments with a system capable of handling up to 150,000 gpd of water. The existing demonstration system is available for field tests at a DOE facility or remediation site. Replacement of the current short air stripping tower (effective height 3 m) with a taller tower is recommended to improve VOC removal.

  1. Characterization of Physically and Chemically Separated Athabasca Asphaltenes Using Small-Angle X-ray Scattering

    SciTech Connect

    Amundaraín Hurtado, Jesús Leonardo; Chodakowski, Martin; Long, Bingwen; Shaw, John M.

    2012-02-07

    Athabasca asphaltenes were characterized using small-angle X-ray scattering (SAXS). Two methods were used to separate asphaltenes from the Athabasca bitumen: namely, chemical separation by precipitation with n-pentane and physical separation by nanofiltration using a zirconia membrane with a 20 nm average pore size. The permeate and chemically separated samples were diluted in 1-methylnaphtalene and n-dodecane prior to SAXS measurements. The temperature and asphaltene concentration ranges were 50-310 C and 1-10.4 wt %, respectively. Model-independent analysis of SAXS data provided the radius of gyration and the scattering coefficients. Model-dependent fits provided size distributions for asphaltenes assuming that they are dense and spherical. Model-independent analysis for physically and chemically separated asphaltenes showed significant differences in nominal size and structure, and the temperature dependence of structural properties. The results challenge the merits of using chemically separated asphaltene properties as a basis for asphaltene property prediction in hydrocarbon resources. While the residuals for model-dependent fits are small, the results are inconsistent with the structural parameters obtained from model-independent analysis.

  2. Chemical separation of Mo and W from terrestrial and extraterrestrial samples via anion exchange chromatography.

    PubMed

    Nagai, Yuichiro; Yokoyama, Tetsuya

    2014-05-20

    A new two-stage chemical separation method was established using an anion exchange resin, Eichrom 1 × 8, to separate Mo and W from four natural rock samples. First, the distribution coefficients of nine elements (Ti, Fe, Zn, Zr, Nb, Mo, Hf, Ta, and W) under various chemical conditions were determined using HCl, HNO3, and HF. On the basis of the obtained distribution coefficients, a new technique for the two-stage chemical separation of Mo and W, along with the group separation of Ti-Zr-Hf, was developed as follows: 0.4 M HCl-0.5 M HF (major elements), 9 M HCl-0.05 M HF (Ti-Zr-Hf), 9 M HCl-1 M HF (W), and 6 M HNO3-3 M HF (Mo). After the chemical procedure, Nb remaining in the W fraction was separated using 9 M HCl-3 M HF. On the other hand, Nb and Zn remaining in the Mo fraction were removed using 2 M HF and 6 M HCl-0.1 M HF. The performance of this technique was evaluated by separating these elements from two terrestrial and two extraterrestrial samples. The recovery yields for Mo, W, Zr, and Hf were nearly 100% for all of the examined samples. The total contents of the Zr, Hf, W, and Mo in the blanks used for the chemical separation procedure were 582, 9, 29, and 396 pg, respectively. Therefore, our new separation technique can be widely used in various fields of geochemistry, cosmochemistry, and environmental sciences and particularly for multi-isotope analysis of these elements from a single sample with significant internal isotope heterogeneities. PMID:24801276

  3. Method of Separating Oxygen From Spacecraft Cabin Air to Enable Extravehicular Activities

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2013-01-01

    Extravehicular activities (EVAs) require high-pressure, high-purity oxygen. Shuttle EVAs use oxygen that is stored and transported as a cryogenic fluid. EVAs on the International Space Station (ISS) presently use the Shuttle cryo O2, which is transported to the ISS using a transfer hose. The fluid is compressed to elevated pressures and stored as a high-pressure gas. With the retirement of the shuttle, NASA has been searching for ways to deliver oxygen to fill the highpressure oxygen tanks on the ISS. A method was developed using low-pressure oxygen generated onboard the ISS and released into ISS cabin air, filtering the oxygen from ISS cabin air using a pressure swing absorber to generate a low-pressure (high-purity) oxygen stream, compressing the oxygen with a mechanical compressor, and transferring the high-pressure, high-purity oxygen to ISS storage tanks. The pressure swing absorber (PSA) can be either a two-stage device, or a single-stage device, depending on the type of sorbent used. The key is to produce a stream with oxygen purity greater than 99.5 percent. The separator can be a PSA device, or a VPSA device (that uses both vacuum and pressure for the gas separation). The compressor is a multi-stage mechanical compressor. If the gas flow rates are on the order of 5 to 10 lb (.2.3 to 4.6 kg) per day, the compressor can be relatively small [3 16 16 in. (.8 41 41 cm)]. Any spacecraft system, or other remote location that has a supply of lowpressure oxygen, a method of separating oxygen from cabin air, and a method of compressing the enriched oxygen stream, has the possibility of having a regenerable supply of highpressure, high-purity oxygen that is compact, simple, and safe. If cabin air is modified so there is very little argon, the separator can be smaller, simpler, and use less power.

  4. Simulation of multistream plate-fin heat exchangers of an air separation unit

    NASA Astrophysics Data System (ADS)

    Boehme, R.; Parise, J. A. R.; Pitanga Marques, R.

    2003-06-01

    Hot and cold reversible heat exchangers of an air separation unit are simulated. Five fluid streams exchange heat with six fluid streams in parallel and counter flow. The numerical method employed divides the heat exchanger in a number of sections, for which fluid properties, capacity rates and heat transfer coefficients are considered constant. Single and two-phase streams are taken into account. Results obtained from the model are compared with field data.

  5. Excitation and separation of vortex modes in twisted air-core fiber.

    PubMed

    Ye, Jingfu; Li, Yan; Han, Yanhua; Deng, Duo; Guo, Zhongyi; Gao, Jianmin; Sun, Qiaoqun; Liu, Yi; Qu, Shiliang

    2016-04-18

    An air-core fiber imposed by torsion is investigated in this paper. We refer to this kind of fiber as twisted air-core fiber (TAF). It has been demonstrated that the eigenstates of the TAF consist of guided optical vortex waves with different propagation constants of a different effective index. With the increase of the twist rate, TAF could separate the OAM modes which are near degenerate or degenerate in the air-core fiber. The separation of OAM modes in TAF is conductive to ultralong distance propagation with low crosstalk. TAF could be considered as an ideal candidate fiber for OAM based optical communication. Moreover, we investigated the twisted air-core photonic crystal fiber (TAPCF) which can improve the relative energy distribution of the OAM modes. Compared with TAF, more energy is located in the ring shaped core, which is conductive to ultralong distance propagation. TAF and TAPCF are of potential interest for increasing channel capacity in optical telecommunications, and the result is also of interest to the photonic crystal community. PMID:27137269

  6. Integrated separation and optical detection for novel on-chip chemical analysis

    SciTech Connect

    Warren, M.E.; Anex, D.S.; Rakestraw, D.; Gourley, P.L.

    1998-03-01

    This report represents the completion of a two years Laboratory Directed Research and Development (LDRD) program to investigate miniaturized systems for chemical detection and analysis. The future of advanced chemical detection and analysis is in miniature devices that are able to characterize increasingly complex samples, a laboratory on a chip. In this concept, chemical operations used to analyze complicated samples in a chemical laboratory sample handling, species separation, chemical derivitization and detection are incorporated into a miniature device. By using electrokinetic flow, this approach does not require pumps or valves, as fluids in microfabricated channels can be driven by externally applied voltages. This is ideal for sample handling in miniature devices. This project was to develop truly miniature on-chip optical systems based on Vertical Cavity Surface Emitting Lasers (VCSELs) and diffractive optics. These can be built into a complete system that also has on-chip electrokinetic fluid handling and chemical separation in a microfabricated column. The primary goal was the design and fabrication of an on-chip separation column with fluorescence sources and detectors that, using electrokinetic flow, can be used as the basis of an automated chemical analysis system. Secondary goals involved investigation of a dispersed fluorescence module that can be used to extend the versatility of the basic system and on chip, intracavity laser absorption as a high sensitivity detection technique.

  7. Visualization of Air Particle Dynamics in an Engine Inertial Particle Separator

    NASA Astrophysics Data System (ADS)

    Wolf, Jason; Zhang, Wei

    2015-11-01

    Unmanned Aerial Vehicles (UAVs) are regularly deployed around the world in support of military, civilian and humanitarian efforts. Due to their unique mission profiles, these advanced UAVs utilize various internal combustion engines, which consume large quantities of air. Operating these UAVs in areas with high concentrations of sand and dust can be hazardous to the engines, especially during takeoff and landing. In such events, engine intake filters quickly become saturated and clogged with dust particles, causing a substantial decrease in the UAVs' engine performance and service life. Development of an Engine Air Particle Separator (EAPS) with high particle separation efficiency is necessary for maintaining satisfactory performance of the UAVs. Inertial Particle Separators (IPS) have been one common effective method but they experience complex internal particle-laden flows that are challenging to understand and model. This research employs an IPS test rig to simulate dust particle separation under different flow conditions. Soda lime glass spheres with a mean diameter of 35-45 microns are used in experiments as a surrogate for airborne particulates encountered during flight. We will present measurements of turbulent flow and particle dynamics using flow visualization techniques to understand the multiphase fluid dynamics in the IPS device. This knowledge can contribute to design better performing IPS systems for UAVs. Cleveland State University, Cleveland, Ohio, 44115.

  8. Modeling of Gamma-ray Spectra to Direct Efficient Chemical Separations

    SciTech Connect

    Douglas, Matthew; Friese, Judah I.; Warren, Glen A.; Bachelor, Paula P.; Farmer, Orville T.; Choiniere, Andrea D.; Schulte, Shannon M.; Aalseth, Craig E.

    2008-06-15

    In an age of heightened national security regarding nuclear terrorist threats, reliable and rapid analytical methods for the quantification of radionuclides in fission product samples are needed to provide forensic information and sample characterization. Measurement of characteristic gamma-ray emissions by high-purity germanium spectrometers offers one means of analysis. Due to the high-activity and complex nature of samples, chemical separations are necessary to reduce background continuum levels and instances of spectral interference. A project has been initiated at Pacific Northwest National Laboratory (PNNL) to model singles and coincident gamma-ray spectra that would result from various chemical separation strategies. The goal is to use these complementary counting techniques to tailor a series of efficient chemical separations that allow the rapid quantification of signature isotopes in samples. Modeling enables probable instances of spectral interference to be identified and aids in defining the temporal window of detection for radionuclides of interest following a given chemical separation. These data will help future analysts prioritize analytes of interest and separation strategies in the processing of real samples. A description of results to date is described here, demonstrating the utility of this approach for improved processing and analysis of fission product samples.

  9. Hazard Assessment of Chemical Air Contaminants Measured in Residences

    SciTech Connect

    Logue, J.M.; McKone, T.E.; Sherman, M. H.; Singer, B.C.

    2010-05-10

    Identifying air pollutants that pose a potential hazard indoors can facilitate exposure mitigation. In this study, we compiled summary results from 77 published studies reporting measurements of chemical pollutants in residences in the United States and in countries with similar lifestyles. These data were used to calculate representative mid-range and upper bound concentrations relevant to chronic exposures for 267 pollutants and representative peak concentrations relevant to acute exposures for 5 activity-associated pollutants. Representative concentrations are compared to available chronic and acute health standards for 97 pollutants. Fifteen pollutants appear to exceed chronic health standards in a large fraction of homes. Nine other pollutants are identified as potential chronic health hazards in a substantial minority of homes and an additional nine are identified as potential hazards in a very small percentage of homes. Nine pollutants are identified as priority hazards based on the robustness of measured concentration data and the fraction of residences that appear to be impacted: acetaldehyde; acrolein; benzene; 1,3-butadiene; 1,4-dichlorobenzene; formaldehyde; naphthalene; nitrogen dioxide; and PM{sub 2.5}. Activity-based emissions are shown to pose potential acute health hazards for PM{sub 2.5}, formaldehyde, CO, chloroform, and NO{sub 2}.

  10. Chemical Instability of Dimethyl Sulfoxide in Lithium-Air Batteries.

    PubMed

    Kwabi, David G; Batcho, Thomas P; Amanchukwu, Chibueze V; Ortiz-Vitoriano, Nagore; Hammond, Paula; Thompson, Carl V; Shao-Horn, Yang

    2014-08-21

    Although dimethyl sulfoxide (DMSO) has emerged as a promising solvent for Li-air batteries, enabling reversible oxygen reduction and evolution (2Li + O2 ⇔ Li2O2), DMSO is well known to react with superoxide-like species, which are intermediates in the Li-O2 reaction, and LiOH has been detected upon discharge in addition to Li2O2. Here we show that toroidal Li2O2 particles formed upon discharge gradually convert into flake-like LiOH particles upon prolonged exposure to a DMSO-based electrolyte, and the amount of LiOH detectable increases with increasing rest time in the electrolyte. Such time-dependent electrode changes upon and after discharge are not typically monitored and can explain vastly different amounts of Li2O2 and LiOH reported in oxygen cathodes discharged in DMSO-based electrolytes. The formation of LiOH is attributable to the chemical reactivity of DMSO with Li2O2 and superoxide-like species, which is supported by our findings that commercial Li2O2 powder can decompose DMSO to DMSO2, and that the presence of KO2 accelerates both DMSO decomposition and conversion of Li2O2 into LiOH. PMID:26278088

  11. Air separation membranes : an alternative to EGR in large bore natural gas engines.

    SciTech Connect

    Biruduganti, M.; Gupta, S.; Bihari, B.; McConnell, S.; Sekar, R.; Energy Systems

    2010-08-01

    Air separation membranes (ASMs) could potentially replace exhaust gas recirculation (EGR) technology in engines due to the proven benefits in NOx reduction but without the drawbacks of EGR. Previous investigations of nitrogen-enriched air (NEA) combustion using nitrogen bottles showed up to 70% NOx reduction with modest 2% nitrogen enrichment. The investigation in this paper was performed with an ASM capable of delivering at least 3.5% NEA to a single-cylinder spark-ignited natural gas engine. Low temperature combustion is one of the pathways to meet the mandatory ultra low NOx emissions levels set by regulatory agencies. In this study, a comparative assessment is made between natural gas combustion in standard air and 2% NEA. Enrichment beyond this level degraded engine performance in terms of power density, brake thermal efficiency (BTE), and unburned hydrocarbon emissions for a given equivalence ratio. The ignition timing was optimized to yield maximum brake torque for standard air and NEA. Subsequently, conventional spark ignition was replaced by laser ignition (LI) to extend lean ignition limit. Both ignition systems were studied under a wide operating range from {Psi} :1.0 to the lean misfire limit. It was observed that with 2% NEA, for a similar fuel quantity, the equivalence ratio {Psi} increases by 0.1 relative to standard air conditions. Analysis showed that lean burn operation along with NEA and alternative ignition source, such as LI, could pave the pathway for realizing lower NO{sub x} emissions with a slight penalty in BTE.

  12. Performance analysis of small capacity liquid nitrogen generator based on Joule-Thomson refrigerator coupled with air separation membrane

    NASA Astrophysics Data System (ADS)

    Piotrowska-Hajnus, Agnieszka; Chorowski, Maciej

    2012-06-01

    Joule - Thomson small capacity refrigerators supplied with gas mixture are studied theoretically and experimentally for a variety of applications. They can be especially promising when coupled with membrane air separators. We present liquid nitrogen generation system based on Joule - Thomson cooler joined with air separation membrane. Hollow fiber membrane is used for nitrogen separation from compressed and purified atmospheric air. Joule-Thomson refrigerator operates with a dedicated nitrogen - hydrocarbons mixture and provides a cooling power used for the separated nitrogen liquefaction. Special attention has been paid to a heat exchanger coupling the Joule- Thomson refrigerator with the membrane air separator. This paper describes the system design, the procedure of its working parameters optimization and tests results.

  13. Analysis and optimization of an air-launch-to-orbit separation

    NASA Astrophysics Data System (ADS)

    Sohier, Henri; Piet-Lahanier, Helene; Farges, Jean-Loup

    2015-03-01

    In an air-launch-to-orbit, a space rocket is launched from a carrier aircraft. Air-launch-to-orbit appears as particularly interesting for nano- and microsatellites which are generally launched as secondary loads, that is, placed in the conventional launch vehicle's payload section with a larger primary satellite. In an air-launch-to-orbit, a small satellite can be launched alone as a primary load, away from a carrier aircraft, aboard a smaller rocket vehicle, and in doing so, benefit from more flexible dates and trajectories. One of the most important phases of the mission is the separation between the carrier aircraft and the space rocket. A flight simulator including a large number of factors of uncertainties has been especially developed to study the separation, and a safety criteria has been defined with respect to store collision avoidance. It is used for a sensitivity analysis and an optimization of the possible trajectories. The sensitivity analysis first requires a screening method to select unessential factors that can be held constant. The Morris method is amongst the most popular screening methods. It requires limited calculations, but may result in keeping constant an essential factor which would greatly affect the results of the sensitivity analysis. This paper shows that this risk can be important in spite of recent improvements of the Morris method. It presents an adaptation of this method which divides this risk by a factor of ten on a standard test function. It is based on the maximum of the elementary effects instead of their average. The method focuses the calculations on the factors with a low impact, checking the convergence of this set of factors, and uses two different factor variations instead of one. This adaptation of the Morris method is used to limit the amount of the air-launch-to-orbit simulations and simplify the uncertainty domain for analysis by Sobol's method. The aerodynamic perturbations due to wind, the parameters defining the

  14. Chemical separation of primordial Li+ during structure formation caused by nanogauss magnetic field

    NASA Astrophysics Data System (ADS)

    Kusakabe, Motohiko; Kawasaki, Masahiro

    2015-01-01

    During the structure formation, charged and neutral chemical species may have separated from each other at the gravitational contraction in primordial magnetic field (PMF). A gradient in the PMF in a direction perpendicular to the field direction leads to the Lorentz force on the charged species. Resultantly, an ambipolar diffusion occurs, and charged species can move differently from neutral species, which collapses gravitationally during the structure formation. We assume a gravitational contraction of neutral matter in a spherically symmetric structure, and calculate fluid motions of charged and neutral species. It is shown that the charged fluid, i.e. proton, electron, and 7Li+, can significantly decouple from the neutral fluid depending on the field amplitude. The charged species can, therefore, escape from the gravitational collapse. We take the structure mass, the epoch of the gravitational collapse, and the comoving Lorenz force as parameters. We then identify a parameter region for an effective chemical separation. This type of chemical separation can reduce the abundance ratio of Li/H in early structures because of inefficient contraction of 7Li+ ion. Therefore, it may explain Li abundances of Galactic metal-poor stars which are smaller than the prediction in standard big bang nucleosynthesis model. Amplitudes of the PMFs are controlled by a magnetohydrodynamic turbulence. The upper limit on the field amplitude derived from the turbulence effect is close to the value required for the chemical separation.

  15. Compressed sensing for chemical shift-based water-fat separation.

    PubMed

    Doneva, Mariya; Börnert, Peter; Eggers, Holger; Mertins, Alfred; Pauly, John; Lustig, Michael

    2010-12-01

    Multi echo chemical shift-based water-fat separation methods allow for uniform fat suppression in the presence of main field inhomogeneities. However, these methods require additional scan time for chemical shift encoding. This work presents a method for water-fat separation from undersampled data (CS-WF), which combines compressed sensing and chemical shift-based water-fat separation. Undersampling was applied in the k-space and in the chemical shift encoding dimension to reduce the total scanning time. The method can reconstruct high quality water and fat images in 2D and 3D applications from undersampled data. As an extension, multipeak fat spectral models were incorporated into the CS-WF reconstruction to improve the water-fat separation quality. In 3D MRI, reduction factors of above three can be achieved, thus fully compensating the additional time needed in three-echo water-fat imaging. The method is demonstrated on knee and abdominal in vivo data. PMID:20859998

  16. A Review of the Thermodynamic, Transport, and Chemical Reaction Rate Properties of High-temperature Air

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

    Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.

  17. Radiochemical Separation of Group 5 Elements. Model Experiments for Investigation of Dubnium Chemical Behaviour

    SciTech Connect

    Tereshatov, E. E.; Bozhikov, G. A.; Aksenov, N. V.; Starodub, G. Ya.; Vostokin, G. K.; Shishkin, S. V.; Dmitriev, S. N.; Bruchertseifer, H.; Gaeggeler, H. W.

    2007-05-22

    Chemical behaviour of group 5 elements in the aqueous hydrofluoric acid solutions was studied. The radiochemical method for the cation exchange separation of Nb (Pa) and Ta from Zr, Hf and lanthanides is presented. The developed scheme allows excluding of the presence of SF heavy actinides in fractions of separated elements. On the basis of the data of the present work, it is possible to suggest the following order of the stability of the fluoride complexes of group 4 and 5 elements: Nb {approx_equal} Pa > Zr > Hf > Ta. The order of the complex formation is in agreement with theoretical predictions. This analytical procedure can be used in future heavy nuclei synthesis experiments for the separation of dubnium (Db) from other reactions products and for its chemical identification.

  18. Source attribution of air pollution by spatial scale separation using high spatial density networks of low cost air quality sensors

    NASA Astrophysics Data System (ADS)

    Heimann, I.; Bright, V. B.; McLeod, M. W.; Mead, M. I.; Popoola, O. A. M.; Stewart, G. B.; Jones, R. L.

    2015-07-01

    To carry out detailed source attribution for air quality assessment it is necessary to distinguish pollutant contributions that arise from local emissions from those attributable to non-local or regional emission sources. Frequently this requires the use of complex models and inversion methods, prior knowledge or assumptions regarding the pollution environment. In this paper we demonstrate how high spatial density and fast response measurements from low-cost sensor networks may facilitate this separation. A purely measurement-based approach to extract underlying pollution levels (baselines) from the measurements is presented exploiting the different relative frequencies of local and background pollution variations. This paper shows that if high spatial and temporal coverage of air quality measurements are available, the different contributions to the total pollution levels, namely the regional signal as well as near and far field local sources, can be quantified. The advantage of using high spatial resolution observations, as can be provided by low-cost sensor networks, lies in the fact that no prior assumptions about pollution levels at individual deployment sites are required. The methodology we present here, utilising measurements of carbon monoxide (CO), has wide applicability, including additional gas phase species and measurements obtained using reference networks. While similar studies have been performed, this is the first study using networks at this density, or using low cost sensor networks.

  19. Chemical ordering suppresses large-scale electronic phase separation in doped manganites

    NASA Astrophysics Data System (ADS)

    Zhu, Yinyan; Du, Kai; Niu, Jiebin; Lin, Lingfang; Wei, Wengang; Liu, Hao; Lin, Hanxuan; Zhang, Kai; Yang, Tieying; Kou, Yunfang; Shao, Jian; Gao, Xingyu; Xu, Xiaoshan; Wu, Xiaoshan; Dong, Shuai; Yin, Lifeng; Shen, Jian

    2016-04-01

    For strongly correlated oxides, it has been a long-standing issue regarding the role of the chemical ordering of the dopants on the physical properties. Here, using unit cell by unit cell superlattice growth technique, we determine the role of chemical ordering of the Pr dopant in a colossal magnetoresistant (La1-yPry)1-xCaxMnO3 (LPCMO) system, which has been well known for its large length-scale electronic phase separation phenomena. Our experimental results show that the chemical ordering of Pr leads to marked reduction of the length scale of electronic phase separations. Moreover, compared with the conventional Pr-disordered LPCMO system, the Pr-ordered LPCMO system has a metal-insulator transition that is ~100 K higher because the ferromagnetic metallic phase is more dominant at all temperatures below the Curie temperature.

  20. Chemical ordering suppresses large-scale electronic phase separation in doped manganites

    PubMed Central

    Zhu, Yinyan; Du, Kai; Niu, Jiebin; Lin, Lingfang; Wei, Wengang; Liu, Hao; Lin, Hanxuan; Zhang, Kai; Yang, Tieying; Kou, Yunfang; Shao, Jian; Gao, Xingyu; Xu, Xiaoshan; Wu, Xiaoshan; Dong, Shuai; Yin, Lifeng; Shen, Jian

    2016-01-01

    For strongly correlated oxides, it has been a long-standing issue regarding the role of the chemical ordering of the dopants on the physical properties. Here, using unit cell by unit cell superlattice growth technique, we determine the role of chemical ordering of the Pr dopant in a colossal magnetoresistant (La1−yPry)1−xCaxMnO3 (LPCMO) system, which has been well known for its large length-scale electronic phase separation phenomena. Our experimental results show that the chemical ordering of Pr leads to marked reduction of the length scale of electronic phase separations. Moreover, compared with the conventional Pr-disordered LPCMO system, the Pr-ordered LPCMO system has a metal–insulator transition that is ∼100 K higher because the ferromagnetic metallic phase is more dominant at all temperatures below the Curie temperature. PMID:27053071

  1. Elastic oscillations of bubbles separated from an air cavity in a magnetic fluid

    NASA Astrophysics Data System (ADS)

    Polunin, V. M.; Shabanova, I. A.; Karpova, G. V.; Kobelev, N. S.; Ryabtsev, K. S.; Platonov, V. B.; Aref'ev, I. M.

    2015-07-01

    The elastic oscillations of air bubbles separated from an air cavity compressed by the ponderomotive forces of a magnetic field in a magnetic fluid are accompanied by the appearance of an alternating magnetic field component. The frequency of the alternating component corresponds to the frequency of radial bubble oscillations, and this fact is used to determine the bubble size. A great body of experimental data has been obtained from six magnetic fluid samples with different viscosities. Based on these data, histograms illustrating the bubble radius distribution are plotted. The appearance of the alternating magnetic field component caused by bubble oscillations in a magnetized magnetic fluid can be used to develop a fundamentally new method for supplying small metered gas shots to a reactor, as well as to study the boiling process in a magnetic fluid.

  2. Granular size separation investigated by MRI: The role of air-granule interactions

    NASA Astrophysics Data System (ADS)

    Möbius, Matthias E.; Karczmar, Gregory S.; Nagel, Sidney R.; Jaeger, Heinrich M.

    2003-03-01

    Recent experiments have shown the importance of air in the process of size separation in granular materials. We study the air-granular dynamics in the context of an effective permeability of the granular medium. This gives rise to intruder density dependent rise times which can be categorized into three different regimes: For highly permeable media the rise time is density independent, intermediate permeabilities show a non-monotonic rise time vs. density curve. The rise time vs. density is monotonic for poorly permeable media. These media can also exhibit the so called reverse brazil nut effect for low density intruders. We investigate the dynamics of these systems with MRI and high-speed video.

  3. Development of a Smart Release Algorithm for Mid-Air Separation of Parachute Test Articles

    NASA Technical Reports Server (NTRS)

    Moore, James W.

    2011-01-01

    The Crew Exploration Vehicle Parachute Assembly System (CPAS) project is currently developing an autonomous method to separate a capsule-shaped parachute test vehicle from an air-drop platform for use in the test program to develop and validate the parachute system for the Orion spacecraft. The CPAS project seeks to perform air-drop tests of an Orion-like boilerplate capsule. Delivery of the boilerplate capsule to the test condition has proven to be a critical and complicated task. In the current concept, the boilerplate vehicle is extracted from an aircraft on top of a Type V pallet and then separated from the pallet in mid-air. The attitude of the vehicles at separation is critical to avoiding re-contact and successfully deploying the boilerplate into a heatshield-down orientation. Neither the pallet nor the boilerplate has an active control system. However, the attitude of the mated vehicle as a function of time is somewhat predictable. CPAS engineers have designed an avionics system to monitor the attitude of the mated vehicle as it is extracted from the aircraft and command a release when the desired conditions are met. The algorithm includes contingency capabilities designed to release the test vehicle before undesirable orientations occur. The algorithm was verified with simulation and ground testing. The pre-flight development and testing is discussed and limitations of ground testing are noted. The CPAS project performed a series of three drop tests as a proof-of-concept of the release technique. These tests helped to refine the attitude instrumentation and software algorithm to be used on future tests. The drop tests are described in detail and the evolution of the release system with each test is described.

  4. Examination of lignocellulosic fibers for chemical, thermal, and separations properties: Addressing thermo-chemical stability issues

    NASA Astrophysics Data System (ADS)

    Johnson, Carter David

    Natural fiber-plastic composites incorporate thermoplastic resins with fibrous plant-based materials, sometimes referred to as biomass. Pine wood mill waste has been the traditional source of natural fibrous feedstock. In anticipation of a waste wood shortage other fibrous biomass materials are being investigated as potential supplements or replacements. Perennial grasses, agricultural wastes, and woody biomass are among the potential source materials. As these feedstocks share the basic chemical building blocks; cellulose, hemicellulose, and lignin, they are collectively called lignocellulosics. Initial investigation of a number of lignocellulosic materials, applied to fiber-plastic composite processing and material testing, resulted in varied results, particularly response to processing conditions. Less thermally stable lignocellulosic filler materials were physically changed in observable ways: darkened color and odor. The effect of biomass materials' chemical composition on thermal stability was investigated an experiment involving determination of the chemical composition of seven lignocellulosics: corn hull, corn stover, fescue, pine, soy hull, soy stover, and switchgrass. These materials were also evaluated for thermal stability by thermogravimetric analysis. The results of these determinations indicated that both chemical composition and pretreatment of lignocellulosic materials can have an effect on their thermal stability. A second study was performed to investigate what effect different pretreatment systems have on hybrid poplar, pine, and switchgrass. These materials were treated with hot water, ethanol, and a 2:1 benzene/ethanol mixture for extraction times of: 1, 3, 6, 12, and 24 hours. This factorial experiment demonstrated that both extraction time and medium have an effect on the weight percent of extractives removed from all three material types. The extracted materials generated in the above study were then subjected to an evaluation of thermal

  5. Optimal integrated design of air separation unit and gas turbine block for IGCC systems

    SciTech Connect

    Kamath, R.; Grossman, I.; Biegler, L.; Zitney, S.

    2009-01-01

    The Integrated Gasification Combined Cycle (IGCC) systems are considered as a promising technology for power generation. However, they are not yet in widespread commercial use and opportunities remain to improve system feasibility and profitability via improved process integration. This work focuses on the integrated design of gasification system, air separation unit (ASU) and the gas turbine (GT) block. The ASU supplies oxygen to the gasification system and it can also supply nitrogen (if required as a diluent) to the gas turbine block with minimal incremental cost. Since both GT and the ASU require a source of compressed air, integrating the air requirement of these units is a logical starting point for facility optimization (Smith et al., 1997). Air extraction from the GT can reduce or avoid the compression cost in the ASU and the nitrogen injection can reduce NOx emissions and promote trouble-free operation of the GT block (Wimer et al., 2006). There are several possible degrees of integration between the ASU and the GT (Smith and Klosek, 2001). In the case of 'total' integration, where all the air required for the ASU is supplied by the GT compressor and the ASU is expected to be an elevated-pressure (EP) type. Alternatively, the ASU can be 'stand alone' without any integration with the GT. In this case, the ASU operates at low pressure (LP), with its own air compressor delivering air to the cryogenic process at the minimum energy cost. Here, nitrogen may or may not be injected because of the energy penalty issue and instead, syngas humidification may be preferred. A design, which is intermediate between these two cases, involves partial supply of air by the gas turbine and the remainder by a separate air compressor. These integration schemes have been utilized in some IGCC projects. Examples include Nuon Power Plant at Buggenum, Netherlands (both air and nitrogen integration), Polk Power Station at Tampa, US (nitrogen-only integration) and LGTI at Plaquemine

  6. Optimal Integrated Design of Air Separation Unit and Gas Turbine Block for IGCC Systems

    SciTech Connect

    Ravindra S. Kamath; Ignacio E. Grossmann; Lorenz T. Biegler; Stephen E. Zitney

    2009-01-01

    The Integrated Gasification Combined Cycle (IGCC) systems are considered as a promising technology for power generation. However, they are not yet in widespread commercial use and opportunities remain to improve system feasibility and profitability via improved process integration. This work focuses on the integrated design of gasification system, air separation unit (ASU) and the gas turbine (GT) block. The ASU supplies oxygen to the gasification system and it can also supply nitrogen (if required as a diluent) to the gas turbine block with minimal incremental cost. Since both GT and the ASU require a source of compressed air, integrating the air requirement of these units is a logical starting point for facility optimization (Smith et al., 1997). Air extraction from the GT can reduce or avoid the compression cost in the ASU and the nitrogen injection can reduce NOx emissions and promote trouble-free operation of the GT block (Wimer et al., 2006). There are several possible degrees of integration between the ASU and the GT (Smith and Klosek, 2001). In the case of 'total' integration, where all the air required for the ASU is supplied by the GT compressor and the ASU is expected to be an elevated-pressure (EP) type. Alternatively, the ASU can be 'stand alone' without any integration with the GT. In this case, the ASU operates at low pressure (LP), with its own air compressor delivering air to the cryogenic process at the minimum energy cost. Here, nitrogen may or may not be injected because of the energy penalty issue and instead, syngas humidification may be preferred. A design, which is intermediate between these two cases, involves partial supply of air by the gas turbine and the remainder by a separate air compressor. These integration schemes have been utilized in some IGCC projects. Examples include Nuon Power Plant at Buggenum, Netherlands (both air and nitrogen integration), Polk Power Station at Tampa, US (nitrogen-only integration) and LGTI at Plaquemine

  7. A discussion of regulatory requirements and air dispersion modeling approaches applicable to U.S. chemical demilitarization facilities.

    PubMed

    Higgins, B W; Robbins, L B; Litynski, J

    1998-09-01

    Owners of hazardous waste treatment, storage, and disposal facilities, and certain major air pollution sources, must conduct several separate ambient air dispersion modeling analyses before beginning construction of new facilities or modifying existing facilities. These analyses are critical components of the environmental permitting and facility certification processes and must be completed to the satisfaction of federal, state, and local regulatory authorities. The U.S. Army has conducted air dispersion modeling for its proposed chemical agent disposal facilities to fulfill the following environmental regulatory and risk management requirements: (1) Resource Conservation and Recovery Act human health and ecological risk assessment analysis for the hazardous waste treatment and storage permit applications, (2) Quantitative Risk Assessment to support the site-specific risk management programs, and (3) Prevention of Significant Deterioration ambient air impact analysis for the air permit applications. The purpose of these air dispersion modeling studies is to show that the potential impacts on human health and the environment, due to operation of the chemical agent disposal facilities, are acceptable. This paper describes and compares the types of air dispersion models, modeling input data requirements, modeling algorithms, and approaches used to satisfy the three environmental regulatory and risk management requirements listed above. Although this paper discusses only one industry (i.e., chemical demilitarization), the information it contains could help those in other industries who need to communicate to the public the purpose and objectives of each modeling analysis. It may also be useful in integrating the results of each analysis into an overarching summary of compliance and potential risks. PMID:9775760

  8. Optimizing the coating process of organic actinide extractants on magnetically assisted chemical separation particles.

    SciTech Connect

    Buchholz, B. A.; Tuazon, H. E.; Kaminski, M. D.; Aase, S. B.; Nunez, L.; Vandegrift, G. F.; Chemical Engineering; LLNL; California State Polytechnic Univ. at Pomona; Univ. of Illinois; Univ. of Illinois at Chicago

    1997-01-01

    The coatings of ferromagnetic-charcoal-polymer microparticles (1-25 gm) with organic extractants specific for actinides were optimized for use in the magnetically assisted chemical separation (MACS) process. The organic extractants, octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP), coated the particles when a carrier organic solvent was evaporated. Coated particles were heated in an oven overnight to drive off any remaining carrier solvent and fix the extractants on the particles. Partitioning coefficients for americium obtained with the coated particles routinely reached 3000-4000 ml g-1, approximately 10 times the separation efficiency observed with the conventional solvent extraction system using CMPO and TBP.

  9. EMERGING TECHNOLOGY BULLETIN: VOLATILE ORGANIC COMPOUND REMOVAL FROM AIR STREAMS BY MEMBRANES SEPARATION MEMBRANE TECHNOLOGY AND RESEARCH, INC.

    EPA Science Inventory

    This membrane separation technology developed by Membrane Technology and Research (MTR), Incorporated, is designed to remove volatile organic compounds (VOCs) from contaminated air streams. In the process, organic vapor-laden air contacts one side of a membrane that is permeable ...

  10. Advanced air separation for coal gasification-combined-cycle power plants: Final report

    SciTech Connect

    Kiersz, D.F.; Parysek, K.D.; Schulte, T.R.; Pavri, R.E.

    1987-08-01

    Union Carbide Corporation (UCC) and General Electric Company (GE) conducted a study to determine the benefits associated with extending the integration of integrated coal gasification-combined cycle (IGCC) systems to include the air separation plant which supplies oxygen to the gasifiers. This is achieved by extracting air from the gas turbine air compressors to feed the oxygen plant and returning waste nitrogen to the gas turbine. The ''Radiant Plus Convective Design'' (59/sup 0/F ambient temperature case) defined in EPRI report AP-3486 was selected as a base case into which the oxygen plant-gas turbine integration was incorporated and against which it was compared. General Electric Company's participation in evaluating gas turbine and power block performance ensured consistency between EPRI report AP-3486 and this study. Extending the IGCC integration to include an integrated oxygen plant-gas turbine results in a rare combination of benefits - higher efficiency and lower capital costs. Oxygen plant capital costs are over 20% less and the power requirement is reduced significantly. For the IGCC system, the net power output is higher for the same coal feed rate; this results in an overall improvement in heat rate of about 2% coupled with a reduction in capital costs of 2 to 3%. 6 refs., 11 figs., 7 tabs.

  11. Enhanced c2 yields from methane oxidative coupling by means of a separative chemical reactor.

    PubMed

    Tonkovich, A L; Carr, R W; Aris, R

    1993-10-01

    Of the processes for converting natural gas into a more useful chemical feedstock, the oxidative coupling of methane to form ethane and ethylene (C(2)) has perhaps been the most intensively investigated in recent years, but it has proved extremely difficult to obtain C(2) yields in excess of 20 to 25%. Methane oxidative coupling was carried out in a separative chemical reactor that simulated a countercurrent chromatographic moving-bed. This reaction gives 65% methane conversion, 80% C(2) selectivity, and a C(2) yield slightly better than 50% with Sm(2)O(3) catalyst at approximately 1000 K. PMID:17841868

  12. Spatial pattern separation of chemicals and frequency-independent components by terahertz spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuuki; Kawase, Kodo; Ikari, Tomofumi; Ito, Hiromasa; Ishikawa, Youichi; Minamide, Hiroaki

    2003-10-01

    We separated the component spatial patterns of frequency-dependent absorption in chemicals and frequency-independent components such as plastic, paper, and measurement noise in terahertz (THz) spectroscopic images, using known spectral curves. Our measurement system, which uses a widely tunable coherent THz-wave parametric oscillator source, can image at a specific frequency in the range 1-2 THz. The component patterns of chemicals can easily be extracted by use of the frequency-independent components. This method could be successfully used for nondestructive inspection for the detection of illegal drugs and devices of bioterrorism concealed, e.g., inside mail and packages.

  13. Distribution of volatile organic chemicals in outdoor and indoor air

    NASA Technical Reports Server (NTRS)

    Shah, Jitendra J.; Singh, Hanwant B.

    1988-01-01

    The EPA volatile organic chemistry (VOC) national ambient data base (Shah, 1988) is discussed. The 320 chemicals included in the VOC data base are listed. The methods used to obtain the data are reviewed and the availability, accessibility, and operation of the data base are examined. Tables of the daily outdoor concentrations for 66 chemicals and the daily indoor concentrations for 35 chemicals are presented.

  14. Cryogenic separation of oxygen-argon mixture in natural air samples for isotopic and molecular ratios

    NASA Astrophysics Data System (ADS)

    Habeeb Rahman, Keedakkadan; Abe, Osamu

    2014-05-01

    The discovery of mass independent isotope fractionation in oxygen during the formation of ozone in the stratosphere has initiated a wide application in isotope geochemistry field. Separation of oxygen-argon mixture has become the foundation of high precision analysis of Δ17O and δ(O2/Ar) for geochemical applications. Here we present precise and simplified cryogenic separation of argon oxygen mixture from the atmospheric and dissolved air using 30/60 mesh 5A molecular sieve zeolite. A pioneer study of this method was conducted by Thiemens and Meagher in 1984. The column which is made of glass tube contains about 1.1 grams of molecular sieve zeolite and both ends of column was filled with glass wools. The experimental set up was tested for different combination of molecular sieves and slurry temperatures. We found the most efficient condition for the separation was at a column temperature of -103°C. For complete transfer of O2 and Ar mixture usually takes in 15-20 minutes time. The isotopic ratios of oxygen were analyzed using mass spectrometer (Thermo Fischer Delta Plus) relative to reference oxygen-argon mixture at 3V of m/z 32 for both sample and reference side. The signals of m/z 28, 32, and 40 were measured by dynamically to determine oxygen -argon ratio and to check nitrogen contamination. Repeated measurements of atmospheric air yielded a reproducibility (SE n=80) of 0.006, 0.004 and 0.19‰ for δ17O, δ18O and δO2/Ar respectively. The isotopic and molecular fractionation of argon- oxygen mixture during gas adsorption and desorption while using molecular sieve under liquid nitrogen temperature was studied. We have established a linear relationship governing the effect of 13X and 5A molecular sieves on molecular fractionation. And suggested the use of single 1/8" pellet 13X molecular sieve provided a negligible fractionation.

  15. Molecular dynamics study of phase separation in fluids with chemical reactions

    NASA Astrophysics Data System (ADS)

    Krishnan, Raishma; Puri, Sanjay

    2015-11-01

    We present results from the first d =3 molecular dynamics (MD) study of phase-separating fluid mixtures (AB) with simple chemical reactions (A ⇌B ). We focus on the case where the rates of forward and backward reactions are equal. The chemical reactions compete with segregation, and the coarsening system settles into a steady-state mesoscale morphology. However, hydrodynamic effects destroy the lamellar morphology which characterizes the diffusive case. This has important consequences for the phase-separating structure, which we study in detail. In particular, the equilibrium length scale (ℓeq) in the steady state suggests a power-law dependence on the reaction rate ɛ :ℓeq˜ɛ-θ with θ ≃1.0 .

  16. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    SciTech Connect

    Medin, Zach; Cumming, Andrew E-mail: cumming@physics.mcgill.ca

    2014-03-01

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  17. Molecular dynamics study of phase separation in fluids with chemical reactions.

    PubMed

    Krishnan, Raishma; Puri, Sanjay

    2015-11-01

    We present results from the first d=3 molecular dynamics (MD) study of phase-separating fluid mixtures (AB) with simple chemical reactions (A⇌B). We focus on the case where the rates of forward and backward reactions are equal. The chemical reactions compete with segregation, and the coarsening system settles into a steady-state mesoscale morphology. However, hydrodynamic effects destroy the lamellar morphology which characterizes the diffusive case. This has important consequences for the phase-separating structure, which we study in detail. In particular, the equilibrium length scale (ℓ(eq)) in the steady state suggests a power-law dependence on the reaction rate ε:ℓ(eq)∼ε(-θ) with θ≃1.0. PMID:26651704

  18. Krypton separation from ambient air for application in collinear fast beam laser spectroscopy.

    PubMed

    Mohamed, Tarek; Strohaber, James; Nava, Ricardo; Kolomenskii, Alexandre; Thonnard, Norbert; Schuessler, Hans A

    2012-07-01

    A portable apparatus for the separation of krypton from environmental air samples was tested. The apparatus is based on the cryogenic trapping of gases at liquid nitrogen temperature followed by controlled releases at higher temperatures. The setup consists of a liquid nitrogen trap for the removal of H(2)O and CO(2), followed by charcoal-filled coils that sequentially collect and release krypton and other gases providing four stages of gas chromatography to achieve separation and purification of krypton from mainly N(2), O(2), and Ar. Residual reactive gases remaining after the final stage of chromatography are removed with a hot Ti sponge getter. A thermal conductivity detector is used to monitor the characteristic elution times of the various components of condensed gases in the traps during step-wise warming of the traps from liquid nitrogen temperatures to 0 °C, and then to 100 °C. This allows optimizing the switching times of the valves between the stages of gas chromatography so that mainly krypton is selected and loaded to the next stage while exhausting the other gases using a He carrier. A krypton separation efficiency of ~80 % was determined using a quadrupole mass spectrometer. PMID:22549732

  19. Chemical characterization of particulate air pollutants Case studies on indoor air quality, cultural heritage and the marine environment

    NASA Astrophysics Data System (ADS)

    Horemans, Benjamin

    When attempting to discuss the effects of airborne particulate matter (PM), it is important to address both physical and chemical aspects of this pollutant. This work reports on the results of three separate case studies, each approaching a specific problem of air pollution by evaluating the chemical composition of PM. 1. In the US and Europe, office workers often complain about work-related health symptoms. These symptoms are collectively referred as the 'sick building syndrome'. This work could be considered as one of the largest data collections on particulate pollutants in Belgian offices. It helps to understand the sources as well as the behavior and fate of PM at our workplace environments. Especially the chemical information on PM makes the results unique, since it enables a better evaluation of the health risks connected to office dust. 2. The Alhambra and Generalife bring every year more than 3 million people to Granada in Southern Spain. Recently, the increasing urbanization of Granada and the immense pressure of mass tourism form a threat for this heritage. Despite the fact that atmospheric pollutants are known to he potentially aggressive for our cultural patrimony. this case study is the first to assess the effects of environmental aerosols on the Alhambra monument. The results of this study could help decision-makers at the Alhambra and the city of Granada with the formulation of preventive conservation measures. They show how local vehicular traffic is the main source for atmospheric pollution in and around the Alhambra monument. Targeted strategies are necessary in order to maximally preserve these monuments and their UNESCO world cultural heritage label. 3. Excessive input of nitrogen-containing atmospheric nutrients via dry and wet deposition can cause entrophication of marine regions, which is also a common, seasonal phenomenon along the coasts of the North Sea. This study is the first to give a complete quantitative description of the

  20. Calcium isotope separation by chemical exchange with polymer-bound crown compounds

    SciTech Connect

    Jepson, B.E.

    1990-01-01

    Chromatographic separation of calcium isotopes by chemical exchange with polymer-bound 18-crown-6 was investigated. The breakthrough technique of column chromatography was employed to determine the influence of solvent composition and ligand-tether structure on separation coefficients and heterogeneous calcium complex stability. The separation coefficient, {epsilon}, was found to be strongly dependent upon solvent composition. An {epsilon} of 0. 0025{plus minus}0.0002 (95% C.L.) for the {sup 44}Ca/{sup 40}Ca isotope pair was obtained with a 70/30 (by volume) methanol/chloroform solvent mixture at 20.0{degree}C. Differences in the structure of the tether binding the crown ring to the polymer had no influence on {epsilon} at that solvent composition. 8 refs., 5 figs., 1 tab.

  1. HUMAN EXPOSURES TO VOLATILE HALOGENATED ORGANIC CHEMICALS IN INDOOR AND OUTDOOR AIR

    EPA Science Inventory

    Volatile halogenated organic chemicals are found in indoor and outdoor air, often at concentrations substantially above those in remote, unpopulated areas. The outdoor ambient concentrations vary considerably among sampling stations throughout the United States, as well as diurna...

  2. The Automobile and Air Pollution: A Chemical Review of the Problem

    ERIC Educational Resources Information Center

    Wildeman, Thomas R.

    1974-01-01

    Summarizes chemical principles underlying the operation of automobiles and the cause of air pollution, including concentrations of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen. Comments and opinions are made concerning present and future pollution control devices. (CC)

  3. Integrated optics ring-resonator chemical sensor for detection of air contamination

    NASA Technical Reports Server (NTRS)

    Manfreda, A. M.; Homer, M. L.; Ksendzov, A.

    2004-01-01

    We report a silicon nitride-based ring resonator chemical sensor with sensing polymer coating. Its sensitivity to isopropanol in air is at least 50 ppm - well under the permissible exposure level of 400 ppm.

  4. Intregrated optics ring-resonator chemical sensor for detection of air contamination

    NASA Technical Reports Server (NTRS)

    Ksendzov, Alexander; Homer, Margie L.; Manfreda, Allison M.

    2004-01-01

    We report a silicon nitride-based ring resonator chemical sensor with sensing polymer coating. Its sensitivity to isopropanol in air is at least 50 ppm - well under the permissible exposure level of 400 ppm.

  5. Chemical methods for removing radon and radon daughters from air.

    PubMed

    Stein, L

    1972-03-31

    Liquid bromine trifluoride and the solid complexes ClF(2)SbF(6), BrF(2)SbF(6), BrF(4)Sb(2)F(11), IF(4)(SbF(6))(3) and BrF(2)BiF(6) react spontaneously with radon and radon daughters at 25 degrees C, converting the radioelements to nonvolatile ions and compounds. The reagents can be used in gas-scrubbing units to remove radon and radon daughters from air. The halogen fluoride-antimony pentafluoride complexes may be suitable for purifying air in uranium mines and analyzing radon in air, since they have low dissociation pressures at 25 degrees C and are less hazardous to handle than liquid halogen fluorides. PMID:5013675

  6. Air monitoring and detection of chemical and biological agents

    SciTech Connect

    Leonelli, J.; Althouse, M.L.

    1999-06-01

    This volume contains the proceedings of SPIE`s remote sensing symposium which was held November 2--3, 1998 in Boston, Massachusetts. Topics of discussion include the following: system simulations, atmospheric modeling, and performance prediction studies of chemical warfare remote sensing technologies; ultraviolet laser-induced fluorescence and aerosol detection methods for remote sensing of biological warfare agents; passive detection methods for remote detection of chemical warfare agents; and lidar-based system performance assessments, demonstrations, and new concepts for chemical warfare/biological warfare detection.

  7. PORTABLE SAMPLER FOR PESTICIDES AND SEMIVOLATILE INDUSTRIAL ORGANIC CHEMICALS IN AIR

    EPA Science Inventory

    A battery powered, low volume air sampling system utilizing polyurethane form (PUF) as a trapping medium has been developed and evaluated. The sampler provides air flows of up to 4 L/min affording theoretical detection limits of less than 0.1 microgram/cu m for most chemicals tes...

  8. Evaluation of prototype air/fluid separator for Space Station Freedom Health Maintenance Facility

    NASA Technical Reports Server (NTRS)

    Billica, Roger; Smith, Maureen; Murphy, Linda; Kizzee, Victor D.

    1991-01-01

    A prototype air/fluid separator suction apparatus proposed as a possible design for use with the Health Maintenance Facility aboard Space Station Freedom (SSF) was evaluated. A KC-135 parabolic flight test was performed for this purpose. The flights followed the standard 40 parabola profile with 20 to 25 seconds of near-zero gravity in each parabola. A protocol was prepared to evaluate the prototype device in several regulator modes (or suction force), using three fluids of varying viscosity, and using either continuous or intermittent suction. It was felt that a matrixed approach would best approximate the range of utilization anticipated for medical suction on SSF. The protocols were performed in one-gravity in a lab setting to familiarize the team with procedures and techniques. Identical steps were performed aboard the KC-135 during parabolic flight.

  9. Chiral Separation of G-type Chemical Warfare Nerve Agents via Analytical Supercritical Fluid Chromatography

    PubMed Central

    Kasten, Shane A; Zulli, Steven; Jones, Jonathan L; Dephillipo, Thomas; Cerasoli, Douglas M

    2014-01-01

    Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G-type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical-scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the separation, quantitation, and isolation of individual stereoisomers of GA, GB, GD, and GF. Screening various chiral stationary phases (CSPs) for the capacity to provide full baseline separation of the CWNAs revealed that a Regis WhelkO1 (SS) column was capable of separating the enantiomers of GA, GB, and GF, with elution of the P(+) enantiomer preceding elution of the corresponding P(–) enantiomer; two WhelkO1 (SS) columns had to be connected in series to achieve complete baseline resolution. The four diastereomers of GD were also resolved using two tandem WhelkO1 (SS) columns, with complete baseline separation of the two P(+) epimers. A single WhelkO1 (RR) column with inverse stereochemistry resulted in baseline separation of the GD P(–) epimers. The analytical methods described can be scaled to allow isolation of individual stereoisomers to assist in screening and development of countermeasures to organophosphorus nerve agents. Chirality 26:817–824, 2014. © 2014 The Authors. Chirality published by John Wiley Periodicals, Inc. PMID:25298066

  10. COLLECTION, CHEMICAL FRACTIONATION, AND MUTAGENICITY BIOASSAY OF AMBIENT AIR PARTICULATE

    EPA Science Inventory

    The influence of industrialization and consequent increased concentration of urban particulate matter on the incidence of cancer has long been a concern. The first bioassays used to evaluate complex ambient air samples were whole-animal carcinogenesis bioassays. In these studies,...

  11. A dynamic model of the fate of organic chemicals in a multilayered air/soil system: development and illustrative application.

    PubMed

    Ghirardello, Davide; Morselli, Melissa; Semplice, Matteo; Di Guardo, Antonio

    2010-12-01

    A new site-specific, dynamic model (SoilPlus) was developed to simulate the fate of nonionized organic chemicals in the air/litter/soil system; key features of the model are the double-layered air compartment interacting dynamically with multilayered litter and soil compartments, with seasonal dissolved organic carbon (DOC) fluxes. The model describes the soil environment calculating separate mass balances for water, chemical, and organic matter. SoilPlus underwent a process of benchmarking and evaluation in order to reach a satisfying confirmation of its predictive capability. Several simulations were performed to estimate the role of litter and DOC in affecting the fate of a model contaminant for POPs (hexachlorobenzene). The model shows that litter can behave as a buffer in the process of transferring hexachlorobenzene from air to the mineral soil and as a trap when hexachlorobenzene tends to move from a contaminated field toward clean air. DOC seems to behave as a leaching-enhancer in certain climatic conditions (heavy rainfall, high DOC concentrations), but it does not appear to move significant amounts of HCB in a year calculation. PMID:21053937

  12. Discovery of optimal zeolites for challenging separations and chemical conversions through predictive materials modeling

    NASA Astrophysics Data System (ADS)

    Siepmann, J. Ilja; Bai, Peng; Tsapatsis, Michael; Knight, Chris; Deem, Michael W.

    2015-03-01

    Zeolites play numerous important roles in modern petroleum refineries and have the potential to advance the production of fuels and chemical feedstocks from renewable resources. The performance of a zeolite as separation medium and catalyst depends on its framework structure and the type or location of active sites. To date, 213 framework types have been synthesized and >330000 thermodynamically accessible zeolite structures have been predicted. Hence, identification of optimal zeolites for a given application from the large pool of candidate structures is attractive for accelerating the pace of materials discovery. Here we identify, through a large-scale, multi-step computational screening process, promising zeolite structures for two energy-related applications: the purification of ethanol beyond the ethanol/water azeotropic concentration in a single separation step from fermentation broths and the hydroisomerization of alkanes with 18-30 carbon atoms encountered in petroleum refining. These results demonstrate that predictive modeling and data-driven science can now be applied to solve some of the most challenging separation problems involving highly non-ideal mixtures and highly articulated compounds. Financial support from the Department of Energy Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Award DE-FG02-12ER16362 is gratefully acknowledged.

  13. 77 FR 4522 - National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-30

    .... On October 29, 2009 (74 FR 56008), the EPA issued the NESHAP for the nine chemical manufacturing area... in 1999 in the Integrated Urban Air Toxics Strategy, (64 FR 38715, July 19, 1999) (Strategy... requirement in 2011 (76 FR 15308, March 21, 2011). The chemical manufacturing area source categories...

  14. Control of Chemical Effects in the Separation Process of a Differential Mobility / Mass Spectrometer System

    PubMed Central

    Schneider, Bradley B.; Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.

    2013-01-01

    Differential mobility spectrometry (DMS) separates ions on the basis of the difference in their migration rates under high versus low electric fields. Several models describing the physical nature of this field mobility dependence have been proposed but emerging as a dominant effect is the clusterization model sometimes referred to as the dynamic cluster-decluster model. DMS resolution and peak capacity is strongly influenced by the addition of modifiers which results in the formation and dissociation of clusters. This process increases selectivity due to the unique chemical interactions that occur between an ion and neutral gas phase molecules. It is thus imperative to bring the parameters influencing the chemical interactions under control and find ways to exploit them in order to improve the analytical utility of the device. In this paper we describe three important areas that need consideration in order to stabilize and capitalize on the chemical processes that dominate a DMS separation. The first involves means of controlling the dynamic equilibrium of the clustering reactions with high concentrations of specific reagents. The second area involves a means to deal with the unwanted heterogeneous cluster ion populations emitted from the electrospray ionization process that degrade resolution and sensitivity. The third involves fine control of parameters that affect the fundamental collision processes, temperature and pressure. PMID:20065515

  15. A rapid method for the computation of equilibrium chemical composition of air to 15000 K

    NASA Technical Reports Server (NTRS)

    Prabhu, Ramadas K.; Erickson, Wayne D.

    1988-01-01

    A rapid computational method has been developed to determine the chemical composition of equilibrium air to 15000 K. Eleven chemically reacting species, i.e., O2, N2, O, NO, N, NO+, e-, N+, O+, Ar, and Ar+ are included. The method involves combining algebraically seven nonlinear equilibrium equations and four linear elemental mass balance and charge neutrality equations. Computational speeds for determining the equilibrium chemical composition are significantly faster than the often used free energy minimization procedure. Data are also included from which the thermodynamic properties of air can be computed. A listing of the computer program together with a set of sample results are included.

  16. Discovery of optimal zeolites for challenging separations and chemical transformations using predictive materials modeling

    NASA Astrophysics Data System (ADS)

    Bai, Peng; Jeon, Mi Young; Ren, Limin; Knight, Chris; Deem, Michael W.; Tsapatsis, Michael; Siepmann, J. Ilja

    2015-01-01

    Zeolites play numerous important roles in modern petroleum refineries and have the potential to advance the production of fuels and chemical feedstocks from renewable resources. The performance of a zeolite as separation medium and catalyst depends on its framework structure. To date, 213 framework types have been synthesized and >330,000 thermodynamically accessible zeolite structures have been predicted. Hence, identification of optimal zeolites for a given application from the large pool of candidate structures is attractive for accelerating the pace of materials discovery. Here we identify, through a large-scale, multi-step computational screening process, promising zeolite structures for two energy-related applications: the purification of ethanol from fermentation broths and the hydroisomerization of alkanes with 18-30 carbon atoms encountered in petroleum refining. These results demonstrate that predictive modelling and data-driven science can now be applied to solve some of the most challenging separation problems involving highly non-ideal mixtures and highly articulated compounds.

  17. Study of ignition and detonation of hydrocarbon-air mixtures with detailed and reduced chemical mechanisms

    NASA Astrophysics Data System (ADS)

    Varatharajan, Balachandar

    Uncertainties in the chemical-kinetic processes that take place in detonations lead to difficulties in obtaining fundamental knowledge about detonations and in facilitating investigations of practical devices like Pulse Detonation Engines. This research is focused on reducing the chemical-kinetic uncertainties and developing simplified chemical-kinetic descriptions for use in detonation studies. The fuels investigated are acetylene, ethylene and JP-10. Conditions addressed cover initial (post-shock) temperatures between 1000 K and 2500 K, pressures between 0.5 bar and 100 bar and equivalence ratios between 0.5 and 2. An existing detailed mechanism is extended to 175 steps among 37 chemical species by evaluating the rates of several additional reactions relevant for acetylene, ethylene and JP-10 combustion. This mechanism is tested extensively with data from shock-tube studies and flame-speed measurements. Based on the detailed mechanism, short mechanisms are derived for ignition and detonation of acetylene and ethylene in air. Application of steady-state and partial-equilibrium approximations leads to further systematic reduction. A seven-step reduced mechanism is obtained for acetylene detonations, four of which are important during the induction stage and the remaining three are important for the slower carbon-monoxide oxidation and radical-recombination processes that follow the induction stage. The theory of chain-branching thermal explosions is developed using activation-energy asymptotics and is applied for acetylene ignition, leading to an expression for ignition time. For ethylene, the strong dependence of the chemistry on initial temperatures and pressures complicates analysis and leads to identification of separate reduced mechanisms for high and low temperatures. Expressions for ignition time in terms of the elementary reaction rates are also derived. For JP-10 ignition, a reaction set including 27 additional reactions is proposed, which involves overall

  18. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    NASA Astrophysics Data System (ADS)

    Kotowicz, Janusz; Balicki, Adrian; Michalski, Sebastian

    2014-09-01

    Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of `zero-emission' technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

  19. Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

    SciTech Connect

    Abbas, Charles; Beery, Kyle; Orth, Rick; Zacher, Alan

    2007-09-28

    The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50% of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.

  20. Chemical Effects in the Separation Process of a Differential Mobility / Mass Spectrometer System

    PubMed Central

    Schneider, Bradley B.; Covey, Thomas R.; Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.

    2013-01-01

    In differential mobility spectrometry (DMS, also referred to as high field asymmetric waveform ion mobility spectrometry, FAIMS), ions are separated on the basis of the difference in their mobility under high and low electric fields. The addition of polar modifiers to the gas transporting the ions through a DMS enhances the formation of clusters in a field-dependent way and thus amplifies the high and low field mobility difference resulting in increased peak capacity and separation power. Observations of the increase in mobility field dependence are consistent with a cluster formation model, also referred to as the dynamic cluster-decluster model. The uniqueness of chemical interactions that occur between an ion and cluster-forming neutrals increases the selectivity of the separation and the depression of low-field mobility relative to high-field mobility increases the compensation voltage and peak capacity. The effect of polar modifiers on the peak capacity across a broad range of chemicals has been investigated. We discuss the theoretical underpinnings which explain the observed effects. In contrast to the result from polar modifiers, we find that using mixtures of inert gases as the transport gas improve resolution by reducing peak width but has very little effect on peak capacity or selectivity. Inert gases do not cluster and thus do not reduce low field mobility relative to high-field mobility. The observed changes in the differential mobility α parameter exhibited by different classes of compounds when the transport gas contains polar modifiers or has a significant fraction of inert gas can be explained on the basis of the physical mechanisms involved in the separation processes. PMID:20121077

  1. Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

    SciTech Connect

    Bauer, C.B.; Rogers, R.D.; Nunez, L.; Ziemer, M.D.; Pleune, T.T.; Vandegrift, G.F.

    1995-11-01

    A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K{sub d}) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles.

  2. Chemically Stable Covalent Organic Framework (COF)-Polybenzimidazole Hybrid Membranes: Enhanced Gas Separation through Pore Modulation.

    PubMed

    Biswal, Bishnu P; Chaudhari, Harshal D; Banerjee, Rahul; Kharul, Ulhas K

    2016-03-24

    Highly flexible, TpPa-1@PBI-BuI and TpBD@PBI-BuI hybrid membranes based on chemically stable covalent organic frameworks (COFs) could be obtained with the polymer. The loading obtained was substantially higher (50 %) than generally observed with MOFs. These hybrid membranes show an exciting enhancement in permeability (about sevenfold) with appreciable separation factors for CO2/N2 and CO2/CH4. Further, we found that with COF pore modulation, the gas permeability can be systematically enhanced. PMID:26865381

  3. A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations

    SciTech Connect

    Way, J Douglas

    2011-01-21

    This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

  4. Evolution of chemically processed air parcels in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.; Schoeberl, Mark R.

    1994-01-01

    Aircraft, ground-based, and satellite measurements indicate large concentrations of ClO in the lower stratosphere in and near the polar vortex. The amount of local ozone depletion caused by these large ClO concentrations will depend on the relative rates of ozone loss and ClO recovery. ClO recovery occurs when NO(x), from HNO3 photolysis, reacts with ClO to form ClONO2. We show that air parcels with large amounts of ClO will experience a subsequent ozone depletion that depends on the solar zenith angle. When the solar zenith angle is large in the middle of winter, the recovery of the ClO concentration in the parcel is slow relative to ozone depletion. In the spring, when the solar zenith angle is smaller, the ClO recovery is much faster. After ClO recovery, the chlorine chemistry has not returned to normal. The ClO has been converted to ClONO2. ClO production from further encounters with PSCs will be limited by the heterogeneous reaction of ClONO2 with water. Large ozone depletions, of the type seen in the Antarctic, occur only if there is significant irreversible denitrification in the air parcel.

  5. Chemical Interactions and Their Role in the Microphase Separation of Block Copolymer Thin Films

    PubMed Central

    Farrell, Richard A.; Fitzgerald, Thomas G.; Borah, Dipu; Holmes, Justin D.; Morris, Michael A.

    2009-01-01

    The thermodynamics of self-assembling systems are discussed in terms of the chemical interactions and the intermolecular forces between species. It is clear that there are both theoretical and practical limitations on the dimensions and the structural regularity of these systems. These considerations are made with reference to the microphase separation that occurs in block copolymer (BCP) systems. BCP systems self-assemble via a thermodynamic driven process where chemical dis-affinity between the blocks driving them part is balanced by a restorative force deriving from the chemical bond between the blocks. These systems are attracting much interest because of their possible role in nanoelectronic fabrication. This form of self-assembly can obtain highly regular nanopatterns in certain circumstances where the orientation and alignment of chemically distinct blocks can be guided through molecular interactions between the polymer and the surrounding interfaces. However, for this to be possible, great care must be taken to properly engineer the interactions between the surfaces and the polymer blocks. The optimum methods of structure directing are chemical pre-patterning (defining regions on the substrate of different chemistry) and graphoepitaxy (topographical alignment) but both centre on generating alignment through favourable chemical interactions. As in all self-assembling systems, the problems of defect formation must be considered and the origin of defects in these systems is explored. It is argued that in these nanostructures equilibrium defects are relatively few and largely originate from kinetic effects arising during film growth. Many defects also arise from the confinement of the systems when they are ‘directed’ by topography. The potential applications of these materials in electronics are discussed. PMID:19865513

  6. Chemical composition and bioactivity properties of size-fractions separated from a vermicompost humic acid.

    PubMed

    Canellas, Luciano P; Piccolo, Alessandro; Dobbss, Leonardo B; Spaccini, Riccardo; Olivares, Fábio L; Zandonadi, Daniel B; Façanha, Arnoldo R

    2010-01-01

    Preparative high performance size-exclusion chromatography (HPSEC) was applied to humic acids (HA) extracted from vermicompost in order to separate humic matter of different molecular dimension and evaluate the relationship between chemical properties of size-fractions (SF) and their effects on plant root growth. Molecular dimensions of components in humic SF was further achieved by diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY-NMR) based on diffusion coefficients (D), while carbon distribution was evaluated by solid state (CP/MAS) (13)C NMR. Seedlings of maize and Arabidopsis were treated with different concentrations of SF to evaluate root growth. Six different SF were obtained and their carbohydrate-like content and alkyl chain length decreased with decreasing molecular size. Progressive reduction of aromatic carbon was also observed with decreasing molecular size of separated fractions. Diffusion-ordered spectroscopy (DOSY) spectra showed that SF were composed of complex mixtures of aliphatic, aromatic and carbohydrates constituents that could be separated on the basis of their diffusion. All SF promoted root growth in Arabidopsis and maize seedlings but the effects differed according to molecular size and plant species. In Arabidopsis seedlings, the bulk HA and its SF revealed a classical large auxin-like exogenous response, i.e.: shortened the principal root axis and induced lateral roots, while the effects in maize corresponded to low auxin-like levels, as suggested by enhanced principal axis length and induction of lateral roots. The reduction of humic heterogeneity obtained in HPSEC separated size-fractions suggested that their physiological influence on root growth and architecture was less an effect of their size than their content of specific bioactive molecules. However, these molecules may be dynamically released from humic superstructures and exert their bioactivity when weaker is the humic conformational stability as that obtained

  7. Multicoil Dixon chemical species separation with an iterative least-squares estimation method.

    PubMed

    Reeder, Scott B; Wen, Zhifei; Yu, Huanzhou; Pineda, Angel R; Gold, Garry E; Markl, Michael; Pelc, Norbert J

    2004-01-01

    This work describes a new approach to multipoint Dixon fat-water separation that is amenable to pulse sequences that require short echo time (TE) increments, such as steady-state free precession (SSFP) and fast spin-echo (FSE) imaging. Using an iterative linear least-squares method that decomposes water and fat images from source images acquired at short TE increments, images with a high signal-to-noise ratio (SNR) and uniform separation of water and fat are obtained. This algorithm extends to multicoil reconstruction with minimal additional complexity. Examples of single- and multicoil fat-water decompositions are shown from source images acquired at both 1.5T and 3.0T. Examples in the knee, ankle, pelvis, abdomen, and heart are shown, using FSE, SSFP, and spoiled gradient-echo (SPGR) pulse sequences. The algorithm was applied to systems with multiple chemical species, and an example of water-fat-silicone separation is shown. An analysis of the noise performance of this method is described, and methods to improve noise performance through multicoil acquisition and field map smoothing are discussed. PMID:14705043

  8. Liberation characteristics after cryogenic modification and air table separation of discarded printed circuit boards.

    PubMed

    Zhou, Cuihong; Pan, Yongtai; Lu, Maxi; Yang, Changshun

    2016-07-01

    Liberating useful materials from printed circuit boards (PCBs) is challenging because PCBs are flexible and complex in terms of materials and components. In this study, the crushing of PCBs at low-temperature was investigated. The results indicated that when the temperature was decreased to approximately -20 °C, the strength of PCBs decreased and their brittleness increased, making them easier to crush. A double roll crusher was selected to crush the PCBs. The particle size distribution and power consumption were studied under different working conditions. The results showed that the particle size of most of the lumps was in the range 15×20-25×20 mm, and that power consumption was minimal when the frequency of the crusher was 40-50 Hz. A small shredder was used for cryogenic grinding, and it was found that its power consumption strongly depended on the cooling temperature. An orthogonal experiment was conducted, which revealed that a smaller cutter gap and higher rotational speed could achieve higher yield. Furthermore, the results indicated that the air table developed to liberate PCB materials could effectively separate 2.8-0.5mm grade materials. Overall, the results of this study provide an experimental foundation for more effectively recycling discarded PCBs. PMID:26985873

  9. Growing a Chemical Garden at the Air-Fluid Interface.

    PubMed

    Hussein, Salome; Maselko, Jerzy; Pantaleone, James T

    2016-01-26

    Here we grow chemical gardens using a novel, quasi two-dimensional, experimental configuration. Buoyant calcium chloride solution is pumped onto the surface of sodium silicate solution. The solutions react to form a precipitation structure on the surface. Initially, an open channel forms that grows in a spiral. This transitions to radially spreading and branching fingers, which typically oscillate in transparency as they grow. The depth of the radial spreading, and the fractal dimension of the finger growth, are surprisingly robust, being insensitive to the pumping rate. The curvature of the channel membrane and the depth of the radially spreading solution can be explained in terms of the solution densities and the interfacial tension across the semipermeable membrane. These unusually beautiful structures provide new insights into the dynamics of precipitation structures and may lead to new technologies where structures are grown instead of assembled. PMID:26712270

  10. Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater

    SciTech Connect

    Jackson, Dennis G.; Looney, Brian B.; Craig, Robert R.; Thompson, Martha C.; Kmetz, Thomas F.

    2013-07-10

    This study evaluates the removal of mercury from wastewater using chemical reduction and air stripping using a full-scale treatment system at the Savannah River Site. The existing water treatment system utilizes air stripping as the unit operation to remove organic compounds from groundwater that also contains mercury (C ~ 250 ng/L). The baseline air stripping process was ineffective in removing mercury and the water exceeded a proposed limit of 51 ng/L. To test an enhancement to the existing treatment modality a continuous dose of reducing agent was injected for 6-hours at the inlet of the air stripper. This action resulted in the chemical reduction of mercury to Hg(0), a species that is removable with the existing unit operation. During the injection period a 94% decrease in concentration was observed and the effluent satisfied proposed limits. The process was optimized over a 2-day period by sequentially evaluating dose rates ranging from 0.64X to 297X stoichiometry. A minimum dose of 16X stoichiometry was necessary to initiate the reduction reaction that facilitated the mercury removal. Competing electron acceptors likely inhibited the reaction at the lower 1 doses, which prevented removal by air stripping. These results indicate that chemical reduction coupled with air stripping can effectively treat large-volumes of water to emerging part per trillion regulatory standards for mercury.

  11. Rate constants for chemical reactions in high-temperature nonequilibrium air

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1986-01-01

    In the nonequilibrium atmospheric chemistry regime that will be encountered by the proposed Aeroassisted Orbital Transfer Vehicle in the upper atmosphere, where air density is too low for thermal and chemical equilibrium to be maintained, the detailed high temperature air chemistry plays a critical role in defining radiative and convective heating loads. Although vibrational and electronic temperatures remain low (less than 15,000 K), rotational and translational temperatures may reach 50,000 K. Attention is presently given to the effects of multiple temperatures on the magnitudes of various chemical reaction rate constants, for the cases of both bimolecular exchange reactions and collisional excitation and dissociation reactions.

  12. [Characteristic of toxic risks of air pollution by chemical admixtures aboard the piloted orbital stations].

    PubMed

    Mukhamedieva, L N; Bogomolov, V V

    2009-01-01

    Trends in the chemical composition of air revealed by the sanitary-chemical and toxicological investigations in multifactorial ground-based tests and long-term space flights aboard the Salyut- 6, 7, Mir and the International space station have been used to deduce the chemical characteristic and to substantiate methods to and criteria for evaluation of toxic risks to space crews from air chemical pollution. Of particular concern were the toxic risks and crew protection during the first ingress to modules on the stage of station assembly in orbit, in the course of long-term missions, and in the event of acute exposure in off-nominal and emergency conditions. PMID:19711857

  13. DNA aptamers for selective identification and separation of flame retardant chemicals.

    PubMed

    Kim, Un-Jung; Kim, Byoung Chan

    2016-09-14

    Polybrominated diphenyl ethers (PBDEs) are group of chemicals which are representative persistent organic pollutants (POPs) and used as brominated flame retardants for many consumer products. PBDEs were phased out since 2009 but are still frequently observed in various environmental matrices and human body. Here, we report ssDNA aptamers which bind to BDE47, one of the PBDE congeners commonly found in various environmental matrices, and show affinity to other major tri-to hepta- BDE congeners. The PBDE specific aptamers were isolated from random library of ssDNA using Mag-SELEX. Two out of 15 sequences, based on their alignment and hairpin loop structures, were chosen to determine dissociation constant with BDE47 and showed from picomolar to nanomolar affinities (200 pM and 1.53 nM). The aptamers displayed high selectivity to the original target, BDE47, and implying general specificity to PBDE backbone with varying affinities to other congeners. Further, we showed that the use of two aptamers together could enhance the separation efficiency of BDE47 and other BDE congeners when dissolved in a solvent compared to use of single aptamer. These aptamers are expected to provide a tool for preliminary screening or quick separation of PBDEs in environmental samples prior to trace quantitative analysis. PMID:27566357

  14. Separation of thiol and cyanide hydrolysis products of chemical warfare agents by capillary electrophoresis.

    PubMed

    Copper, Christine L; Collins, Greg E

    2004-03-01

    The fluorescence derivatizing agent, o-phthalaldehyde (OPA), has been applied to the separation and detection of cyanide and several structurally similar thiols by capillary electrophoresis (CE)-laser induced fluorescence (LIF). Of particular interest to this investigation was the separation of 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, and cyanide, each of which are hydrolysis products or hydrolysis product simulants of the chemical warfare (CW) agents O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), O-isobutyl S-2-diethylaminoethyl methylphosphonothiolate (R-VX), and tabun (GA). Other structurally similar thiols simultaneously resolved by this method include 1-pentanethiol and 2-mercaptoethanol. Instrumental parameters were probed and optimum values for capillary length (50 cm) and inner diameter (75 microm), injection time (30 s) and field strength (15 kV) were determined. Sample stacking methods enabled detection limits of 9.3 microg/L for cyanide, 1.8 microg/L for 2-diethylaminoethanethiol, 35 microg/L for 2-dimethylaminoethanethiol, 15 microg/L for 2-mercaptoethanol, and 89 microg/L for 1-pentanethiol. The linearity of the method was verified over an order of magnitude and the reproducibility was found to be 3.0%. PMID:15004852

  15. Field Evidence for Strong Chemical Separation of Contaminants in the Hanford Vadose Zone

    SciTech Connect

    Conrad, Mark E.; Depaolo, D. J.; Maher, Katharine; Gee, Glendon W.; Ward, Anderson L.

    2007-11-01

    Water and chemical transport from a point source within vadose zone sediments at the Hanford Site in Washington State were examined with a leak test consisting of five 3800-L aliquots of water released at 4.5-m depth every week over a 4-wk period. The third aliquot contained bromide, D2O, and 87Sr. Movement of the tracers was monitored for 9 mo by measuring pore water compositions of samples from boreholes drilled 2 to 8 m from the injection point. Graded sedimentary layers acting as natural capillary barriers caused significant lateral spreading of the leak water. Shortly after injections were completed, D2O was found at the 9- to 11-m depth at levels in excess of 50% of the tracer aliquot concentration, while sediment layers with elevated water content at the 6- to 7-m depth had less than 3% of the D2O tracer concentration, suggesting deep penetration of the D2O tracer and limited mixing between different aliquots of leak fluids. Initially, high bromide concentrations decreased more rapidly over time than D2O, suggesting enhanced transport of bromide due to anion exclusion. No significant increase in 87Sr was detected in the sampled pore water, indicating strong retardation of Sr by the sediments. These results highlight some of the processes strongly affecting chemical transport in the vadose zone and demonstrate the significant separation of contaminant plumes that can occur.

  16. Field evidence for strong chemical separation of contaminants inthe Hanford Vadose Zone

    SciTech Connect

    Conrad, Mark E.; DePaolo, Donald J.; Maher, Katharine; Gee,Glendon W.; Ward, Anderson L.

    2007-04-10

    Water and chemical transport from a point source withinvadose zone sediments at Hanford were examined with a leak testconsisting of five 3800-liter aliquots of water released at 4.5 m depthevery week over a 4-week period. The third aliquot contained bromide, D2Oand 87Sr. Movement of the tracers was monitored for 9 months by measuringpore water compositions of samples from boreholes drilled 2-8 m from theinjection point. Graded sedimentary layers acting as natural capillarybarriers caused significant lateral spreading of the leak water. D2Oconcentrations>50 percent of the concentration in the tracer aliquotwere detected at 9-11 m depth. However, increased water contents, lowerd18O values, and geophysical monitoring of moisture changes at otherdepths signified high concentrations of leak fluids were added where D2Oconcentrations were<3 percent above background, suggesting limitedmixing between different aliquots of the leak fluids. Initially highbromide concentrations decreased more rapidly over time than D2O,suggesting enhanced transport of bromide due to anion exclusion. Nosignificant increase in 87Sr was detected in the sampled pore water,indicating strong retardation of Sr by the sediments. These resultshighlight some of the processes strongly affecting chemical transport inthe vadose zone and demonstrate the significant separation of contaminantplumes that can occur.

  17. CHOOSING A CHEMICAL MECHANISM FOR REGULATORY AND RESEARCH AIR QUALITY MODELING APPLICATIONS

    EPA Science Inventory

    There are numerous, different chemical mechanisms currently available for use in air quality models, and new mechanisms and versions of mechanisms are continually being developed. The development of Morphecule-type mechanisms will add a near-infinite number of additional mecha...

  18. Hydrogen and electricity from coal with carbon dioxide separation using chemical looping reactors

    SciTech Connect

    Xiang Wenguo; Chen Yingying

    2007-08-15

    Concern about global climate change has led to research on low CO{sub 2} emission in the process of the energy conversion of fossil fuel. One of the solutions is the conversion of fossil fuel into carbon-free energy carriers, hydrogen, and electricity with CO{sub 2} capture and storage. In this paper, the main purpose is to investigate the thermodynamics performance of converting coal to a hydrogen and electricity system with chemical-looping reactors and to explore the influences of operating parameters on the system performance. Using FeO/Fe{sub 3}O{sub 4} as an oxygen carrier, we propose a carbon-free coproduction system of hydrogen and electricity with chemical-looping reactors. The performance of the new system is simulated using ASPEN PLUS software tool. The influences of the chemical-looping reactor's temperature, steam conversion rate, and O{sub 2}/coal quality ratio on the system performance, and the exergy performance are discussed. The results show that a high-purity of H{sub 2} (99.9%) is reached and that CO{sub 2} can be separated. The system efficiency is 57.85% assuming steam reactor at 815 C and the steam conversion rate 37%. The system efficiency is affected by the steam conversion rate, rising from 53.17 to 58.33% with the increase of the steam conversion rate from 28 to 41%. The exergy efficiency is 54.25% and the losses are mainly in the process of gasification and HRSG. 14 refs., 12 figs., 3 tabs.

  19. Flow processes in overexpanded chemical rocket nozzles. Part 1: Flow separation

    NASA Technical Reports Server (NTRS)

    Schmucker, R. H.

    1973-01-01

    An investigation was made of published nozzle flow separation data in order to determine the parameters which affect the separation condition. A comparison of experimental data with empirical and theoretical separation prediction methods leads to the selection of suitable equations for the separation criterion. The results were used to predict flow separation of the main space shuttle engine.

  20. Flow processes in overexpanded chemical rocket nozzles. Part 1: Flow separation

    NASA Technical Reports Server (NTRS)

    Schmucker, R. H.

    1984-01-01

    An investigation was made of published nozzle flow separation data in order to determine the parameters which affect the separation conditions. A comparison of experimental data with empirical and theoretical separation prediction methods leads to the selection of suitable equations for the separation criterion. The results were used to predict flow separation of the main space shuttle engine.

  1. Chemical and Trajectory Analysis of an Air Mass Plume from Asia

    NASA Astrophysics Data System (ADS)

    Guo, J. J.; Marrero, J. E.; Blake, D. R.

    2014-12-01

    Tracking the source of pollution events is important in understanding the transport of pollution plumes and impact on areas far from the source. Previous studies have shown that the rising contribution of Asian air pollution to the US has increased the number of days that pollution events exceed National Ambient Air Quality Standards (NAAQS). Whole air samples collected over the Edwards Air Force Base during a June 2014 NASA Student Airborne Research Program (SARP) flight exhibited enhancements in the concentrations of several compounds between 23-32 thousand feet. Chemical tracer analysis of these high altitude samples reveal that the air does not correspond to California emitted air. Chemical signatures in the plume, including high levels of OCS, chloroform, and methyl chloride, and low levels of methyl bromide, indicate that the plume was most heavily influence by coal combustion with contributions from biomass burning events from Asia. Low concentrations of ethene at the high altitude despite enhanced concentrations of ethane and ethyne suggest that this plume was aged. Further analysis of the plume using meteorological wind trajectories reveal that the plume had originated in China approximately 4-5 days prior. This is faster than results from previous studies that had found a Spring transport time of approximately 6 days.

  2. Effect of coverage density and structure of chemically bonded silica stationary phases on the separation of compounds with various properties.

    PubMed

    Buszewski, Bogusław; Krupczyńska, Katarzyna; Rychlicki, Gerhard; Lobiński, Ryszard

    2006-04-01

    The chemical character, geometry, and architecture of chemically formed surface layers determine interactions between stationary phase, analyte, and mobile phase, and therefore the retention mechanisms (partitioning, adsorption, ion exchange, steric exclusion) of separated analytes. These interactions also depend on the structure and chemical character of the solutes and the composition of the mobile phase. High-molecular-weight fullerenes (C60 and C70) and water-soluble selenium-containing peptides (833 and 2607 Da) were used for the evaluation of laboratory-prepared octadecyl stationary phases with high and low coverage density before and after end-capping. The aim of this work was to study differences in surface coverage density and homogeneity and conformational changes of chemically bonded moieties and the influence of these parameters on the separation of mixtures of selenopeptides and fullerenes with significantly different molecular masses. A topographical model of the chemically modified stationary surface is presented. PMID:16830495

  3. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  4. Multiparametric fat–water separation method for fast chemical-shift imaging guidance of thermal therapies

    PubMed Central

    Lin, Jonathan S.; Hwang, Ken-Pin; Jackson, Edward F.; Hazle, John D.; Jason Stafford, R.; Taylor, Brian A.

    2013-01-01

    Purpose: A k-means-based classification algorithm is investigated to assess suitability for rapidly separating and classifying fat/water spectral peaks from a fast chemical shift imaging technique for magnetic resonance temperature imaging. Algorithm testing is performed in simulated mathematical phantoms and agar gel phantoms containing mixed fat/water regions. Methods: Proton resonance frequencies (PRFs), apparent spin-spin relaxation (T2*) times, and T1-weighted (T1-W) amplitude values were calculated for each voxel using a single-peak autoregressive moving average (ARMA) signal model. These parameters were then used as criteria for k-means sorting, with the results used to determine PRF ranges of each chemical species cluster for further classification. To detect the presence of secondary chemical species, spectral parameters were recalculated when needed using a two-peak ARMA signal model during the subsequent classification steps. Mathematical phantom simulations involved the modulation of signal-to-noise ratios (SNR), maximum PRF shift (MPS) values, analysis window sizes, and frequency expansion factor sizes in order to characterize the algorithm performance across a variety of conditions. In agar, images were collected on a 1.5T clinical MR scanner using acquisition parameters close to simulation, and algorithm performance was assessed by comparing classification results to manually segmented maps of the fat/water regions. Results: Performance was characterized quantitatively using the Dice Similarity Coefficient (DSC), sensitivity, and specificity. The simulated mathematical phantom experiments demonstrated good fat/water separation depending on conditions, specifically high SNR, moderate MPS value, small analysis window size, and low but nonzero frequency expansion factor size. Physical phantom results demonstrated good identification for both water (0.997 ± 0.001, 0.999 ± 0.001, and 0.986 ± 0.001 for DSC, sensitivity, and specificity, respectively

  5. Initial proof-of-principle for near room temperature Xe and Kr separation from air with MOFs

    SciTech Connect

    Thallapally, Praveen K.; Strachan, Denis M.

    2012-06-06

    Materials were developed and tested in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Technology Separations and Waste Forms Campaign. Specifically, materials are being developed for the removal of Xenon and krypton from gaseous products of nuclear fuel reprocessing unit operations. During FY 2012, Three Metal organic framework (MOF) structures were investigated in greater detail for the removal and storage of Xe and Kr from air at room temperature. Our breakthrough measurements on Nickel based MOF could capture and separate parts per million levels of Xe from Air (40 ppm Kr, 78% N2, 21% O2, 0.9% Ar, 0.03% CO2). Similarly, the selectivity can be changed from Xe > Kr to Xe < Kr simply by changing the temperature in another MOF. Also for the first time we estimated the cost of the metal organic frameworks in bulk.

  6. The chemical enhancement of the triboelectric separation of coal from pyrite and ash: A novel approach for electrostatic separation of mineral matter from coal. Final report

    SciTech Connect

    Gustafson, R.M.; DiMare, S.; Sabatini, J.

    1992-02-01

    Arthur D. Little, Inc., under contract to the US DOE Pittsburgh Energy Technology Center, has developed a triboelectric separation device for coal beneficiation, that employs an entrained-flow, rotating-cylinder concept. The described apparatus has been used to test the efficacy of chemical pretreatment and in-situ treatment of coal on separation efficiency. Coal particle entrainment is achieved with gaseous carbon dioxide and particle collection is accomplished by an electrostatic plate separator. The triboelectric separation device incorporates instrumentation for the direct measurement of charge in the dilute-phase particle stream. Some of the pretreatment materials investigated under this project to modify the surface charging characteristics of the coal included oleic acid, sodium oleate, quinoline and dicyclohexylamine. Ammonia and sulfur dioxide at a concentration up to 1000 ppM was used for in-situ treatment of the coal, with carbon dioxide as the carrier/inerting gas. Nitrogen was used earlier in the test program as the carrier/inerting gas for the coal, but a severe arcing problem was encountered in the electrostatic collector with nitrogen as the carrier gas. This problem did not occur when carbon dioxide was used. The report covers the chemical treatment employed, and summarizes and interprets the results achieved. In addition, an economic analysis of a full scale system based on this concept is presented.

  7. The chemical enhancement of the triboelectric separation of coal from pyrite and ash: A novel approach for electrostatic separation of mineral matter from coal

    SciTech Connect

    Gustafson, R.M.; DiMare, S.; Sabatini, J.

    1992-02-01

    Arthur D. Little, Inc., under contract to the US DOE Pittsburgh Energy Technology Center, has developed a triboelectric separation device for coal beneficiation, that employs an entrained-flow, rotating-cylinder concept. The described apparatus has been used to test the efficacy of chemical pretreatment and in-situ treatment of coal on separation efficiency. Coal particle entrainment is achieved with gaseous carbon dioxide and particle collection is accomplished by an electrostatic plate separator. The triboelectric separation device incorporates instrumentation for the direct measurement of charge in the dilute-phase particle stream. Some of the pretreatment materials investigated under this project to modify the surface charging characteristics of the coal included oleic acid, sodium oleate, quinoline and dicyclohexylamine. Ammonia and sulfur dioxide at a concentration up to 1000 ppM was used for in-situ treatment of the coal, with carbon dioxide as the carrier/inerting gas. Nitrogen was used earlier in the test program as the carrier/inerting gas for the coal, but a severe arcing problem was encountered in the electrostatic collector with nitrogen as the carrier gas. This problem did not occur when carbon dioxide was used. The report covers the chemical treatment employed, and summarizes and interprets the results achieved. In addition, an economic analysis of a full scale system based on this concept is presented.

  8. Gas turbine engine adapted for use in combination with an apparatus for separating a portion of oxygen from compressed air

    DOEpatents

    Bland, Robert J.; Horazak, Dennis A.

    2012-03-06

    A gas turbine engine is provided comprising an outer shell, a compressor assembly, at least one combustor assembly, a turbine assembly and duct structure. The outer shell includes a compressor section, a combustor section, an intermediate section and a turbine section. The intermediate section includes at least one first opening and at least one second opening. The compressor assembly is located in the compressor section to define with the compressor section a compressor apparatus to compress air. The at least one combustor assembly is coupled to the combustor section to define with the combustor section a combustor apparatus. The turbine assembly is located in the turbine section to define with the turbine section a turbine apparatus. The duct structure is coupled to the intermediate section to receive at least a portion of the compressed air from the compressor apparatus through the at least one first opening in the intermediate section, pass the compressed air to an apparatus for separating a portion of oxygen from the compressed air to produced vitiated compressed air and return the vitiated compressed air to the intermediate section via the at least one second opening in the intermediate section.

  9. Exploratory investigation of the use of area suction to eliminate air-flow separation in diffusers having large expansion angles

    NASA Technical Reports Server (NTRS)

    Holzhauser, Curt A; Hall, Leo P

    1956-01-01

    Tests were made at a mean inlet Mach number of 0.2 with area suction applied to conical diffusers with expansion angles of 30 degrees and 50 degrees and exit to inlet area ratios of 2. Air-flow separation was eliminated with suction mass flows of 3 and 4 percent of the inlet mass flows for the 30 degrees and 50 degrees diffusers, respectively.

  10. Particulate and dissolved phosphorus chemical separation and phosphorus release from treated dairy manure.

    PubMed

    Dao, Thanh H; Daniel, Tommy C

    2002-01-01

    In confined animal feeding operations, liquid manure systems present special handling and storage challenges because of the large volume of diluted wastes. Water treatment polymers and mineral phosphorus (P) immobilizing chemicals [AI2(SO4)3 x 18H2O, FeCl3-6H2O, and Class C fly ash] were used to determine particulate and dissolved reactive phosphorus (DRP) reduction mechanisms in high total suspended solid (TSS) dairy manure and the P release from treated manure and amended soils. Co-application exceeded the aggregation level achieved with individual manure amendments and resulted in 80 and 90% reduction in metal salt and polymer rates, respectively. At marginally effective polymer rates between 0.01 and 0.25 g L(-1), maximal aggregation was attained in combination with 1 and 10 g L(-1) of aluminum sulfate (3 and 30 mmol Al3+ L(-1)) and iron chloride (3.7 and 37 mmol Fe3+ L(-1)) in 30 g L(-1) (TSS30) and 100 g L(-1) TSS (TSS100) suspensions, respectively. Fly ash induced particulate destabilization at rates > or = 50 g L(-1) and reduced solution-phase DRP at all rates > or = 1 g L(-1) by 52 and 71% in TSS30 and TSS100 suspensions, respectively. Aluminum and Fe salts also lowered DRP at rates < or = 10 g L(-1) and higher concentrations redispersed particulates and increased DRP due to increased suspension acidity and electrical conductivity. The DRP release from treated manure solids and a Typic Paleudult amended with treated manure was reduced, although the amendments increased Mehlich 3-extractable P. Therefore, the synergism of flocculant types allowed input reduction in aggregation aid chemicals, enhancing particulate and dissolved P separation and immobilization in high TSS liquid manure. PMID:12175060

  11. Genotoxicity, inflammation and physico-chemical properties of fine particle samples from an incineration energy plant and urban air.

    PubMed

    Sharma, Anoop Kumar; Jensen, Keld Alstrup; Rank, Jette; White, Paul A; Lundstedt, Staffan; Gagne, Remi; Jacobsen, Nicklas R; Kristiansen, Jesper; Vogel, Ulla; Wallin, Håkan

    2007-10-01

    Airborne particulate matter (PM) was sampled by use of an electrostatic sampler in an oven hall and a receiving hall in a waste-incineration energy plant, and from urban air in a heavy-traffic street and from background air in Copenhagen. PM was sampled for 1-2 weeks, four samples at each site. The samples were extracted and examined for mutagenicity in Salmonella typhimurium strains TA98, YG1041 and YG5161, for content of inorganic elements and for the presence of eight polycyclic aromatic hydrocarbons. The induction of IL-6 and IL-8 mRNA expression and the presence of DNA damage - tested by the comet assay - were determined after 24-h incubations with human A549 lung epithelial cells. The PM(2.5) concentration was about twofold greater in the oven hall than in the receiving hall. The particle size distribution in the receiving hall was similar to that in street air (maximum mode at about 25nm), but the distribution was completely different in the oven hall (maximum mode at about 150nm). Also chemically, the samples from the oven hall were highly different from the other samples. PM extracts from the receiving hall, street and background air were more mutagenic than the PM extracts from the oven hall. PM from all four sites caused similar levels of DNA damage in A549 cells; only the oven hall samples gave results that were statistically significantly different from those obtained with street-air samples. The receiving hall and the urban air samples were similarly inflammatory (relative IL-8 mRNA expression), whereas the oven hall did not cause a statistically significant increase in IL-8 mRNA expression. A principal component analysis separated the oven hall and the receiving hall by the first principal component. These two sites were separated from street and background air with the second principal component. Several clusters of constituents were identified. One cluster consisted of all the polycyclic aromatic hydrocarbons (PAH), several groups of metals and one

  12. 40 CFR Table 1 to Subpart Vvvvvv... - Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 14 2010-07-01 2010-07-01 false Hazardous Air Pollutants Used To... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources Pt. 63, Subpt. VVVVVV,...

  13. Chemical and physical analyses of firn and firn air : from Dronning Maud Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Kaspers, K. A.

    2004-10-01

    Important information about the past global climate is preserved in the Antarctic ice. This information becomes available from studying ice cores, where the change in the chemical composition of the past atmosphere is stored. Although ice cores can provide valuable information over a large time span for major atmospheric components, to study the industrial period, the last 150 years, detailed measurements, measuring trace gases components of the past atmosphere, are required. In order to make the analyses of atmospheric trace gasses possible, large volumes of past air are needed. Large volumes of air can be taken from firn air. Firn air is the air that is trapped in the porous medium of firn, which is typically the first one hundred meters of an ice core. In this thesis the firn air analyses of Site M in Dronning Maud Land, Antarctica (15°E, 75°S, 3453 m.a.s.l) are described. These firn air analyses were measured with gas chromatography, yielding concentration profiles with depth for a wide variety of trace gases. In the chapters three and four, the firn air analyses are focussed on the non-methane hydrocarbons (NMHCs): ethane, propane and acetylene, and methyl chloride. The NMHCs were studied because very little is known about their long-term and seasonal trend in the atmosphere around Antarctica and Southern Hemisphere in general whereas these NMHCs play an important role in the atmospheric oxidation chemistry. Studying the long-term and seasonal trend for methyl chloride is very interesting because this gas shows a large spatial variability although this is not expected because of its large lifetime. In chapter three measurements are discussed obtaining a 25-year old record of trace gases. Naturally longer records are more valuable, particularly if pre-industrial levels can be recorded. Although one would expect that old firn air could be found at locations high on the Antarctic plateau, with low temperatures, low accumulation rates and low surface pressures

  14. Evaluation of High Density Air Traffic Operations with Automation for Separation Assurance, Weather Avoidance and Schedule Conformance

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey S.; Martin, Lynne Hazel; Homola, Jeffrey R.; Cabrall, Christopher D.; Brasil, Connie L.

    2011-01-01

    In this paper we discuss the development and evaluation of our prototype technologies and procedures for far-term air traffic control operations with automation for separation assurance, weather avoidance and schedule conformance. Controller-in-the-loop simulations in the Airspace Operations Laboratory at the NASA Ames Research Center in 2010 have shown very promising results. We found the operations to provide high airspace throughput, excellent efficiency and schedule conformance. The simulation also highlighted areas for improvements: Short-term conflict situations sometimes resulted in separation violations, particularly for transitioning aircraft in complex traffic flows. The combination of heavy metering and growing weather resulted in an increased number of aircraft penetrating convective weather cells. To address these shortcomings technologies and procedures have been improved and the operations are being re-evaluated with the same scenarios. In this paper we will first describe the concept and technologies for automating separation assurance, weather avoidance, and schedule conformance. Second, the results from the 2010 simulation will be reviewed. We report human-systems integration aspects, safety and efficiency results as well as airspace throughput, workload, and operational acceptability. Next, improvements will be discussed that were made to address identified shortcomings. We conclude that, with further refinements, air traffic control operations with ground-based automated separation assurance can routinely provide currently unachievable levels of traffic throughput in the en route airspace.

  15. Chemical investigations of isotope separation on line target units for carbon and nitrogen beams

    SciTech Connect

    Fraanberg, H.; Ammann, M.; Gaeggeler, H.W.; Koester, U.

    2006-03-15

    Radioactive ion beams (RIBs) are of significant interest in a number of applications. Isotope separation on line (ISOL) facilities provide RIB with high beam intensities and good beam quality. An atom that is produced within the ISOL target will first diffuse out from the target material. During the effusion towards the transfer line and into the ion source the many contacts with the surrounding surfaces may cause unacceptable delays in the transport and, hence, losses of the shorter-lived isotopes. We performed systematic chemical investigations of adsorption in a temperature and concentration regime relevant for ISOL targets and ion source units, with regard to CO{sub x} and NO{sub x} on Al{sub 2}O{sub 3} and SiO{sub 2}. These materials are potential construction materials for the above-mentioned areas. Off-line and on-line tests have been performed using a gas thermochromatography setup with radioactive tracers. The experiments were performed at the production of tracers for atmospheric chemistry (PROTRAC) facility at the Paul Scherrer Institute in Villigen, Switzerland.

  16. Simulated experiment for elimination of air contaminated with odorous chemical agents by microwave plasma burner

    SciTech Connect

    Hong, Yong Cheol; Shin, Dong Hun; Uhm, Han Sup

    2007-10-15

    An experimental study on elimination of odorous chemical agent was carried out by making use of a microwave plasma burner, which consists of a microwave plasma torch and a reaction chamber with a fuel injector. Injection of hydrocarbon fuels into a high-temperature microwave torch plasma generates a plasma flame. The plasma flame can eliminate the odorous chemical agent diluted in air or purify the interior air of a large volume in isolated spaces. The specially designed reaction chamber eliminated H{sub 2}S and NH{sub 3} diluted in airflow rate of 5000 lpm (liters per minute), showing {beta} values of 46.52 and 39.69 J/l, respectively.

  17. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    SciTech Connect

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-18

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  18. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    NASA Astrophysics Data System (ADS)

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-01

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies an airflow rate of 5000lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  19. A female pelvic bone shape model for air/bone separation in support of synthetic CT generation for radiation therapy

    NASA Astrophysics Data System (ADS)

    Liu, Lianli; Cao, Yue; Fessler, Jeffrey A.; Jolly, Shruti; Balter, James M.

    2016-01-01

    Separating bone from air in MR data is one of the major challenges in using MR images to derive synthetic CT. The problem is further complicated when the anatomic regions filled with air are altered across scans due to air mobility, for instance, in pelvic regions, thereby the air regions estimated using an ultrashort echo time (UTE) sequence are invalid in other image series acquired for multispectral classification. This study aims to develop and investigate a female pelvic bone shape model to identify low intensity regions in MRI where air is unlikely to be present in support of synthetic CT generation without UTE imaging. CT scans of 30 patients were collected for the study, 17 of them also have corresponding MR scans. The shape model was built from the CT dataset, where the reference image was aligned to each of the training images using B-spline deformable registration. Principal component analysis was performed on B-spline coefficients for a compact model where shape variance was described by linear combination of principal modes. The model was applied to identify pelvic bone in MR images by deforming the corresponding MR data of the reference image to target MR images, where the search space of the deformation process was constrained within the subspace spanned by principal modes. The local minima in the search space were removed effectively by the shape model, thus supporting an efficient binary search for the optimal solution. We evaluated the model by its efficacy in identifying bone voxels and excluding air regions. The model was tested across the 17 patients that have corresponding MR scans using a leave-one-out cross validation. A simple model using the first leading principal mode only was found to achieve reasonable accuracy, where an averaged 87% of bone voxels were correctly identified. Finally dilation of the optimally fit bone mask by 5 mm was found to cover 96% of bone voxels while minimally impacting the overlap with air (below 0.4%).

  20. Love Canal Emergency Declaration Area habitability study. Volume 2. Air assessment: indicator chemicals. Final report

    SciTech Connect

    Not Available

    1988-02-01

    Environmental studies were conducted to provide data that could be used by the Commissioner of Health for the State of New York in determining whether the Emergency Declaration Area (EDA) surrounding the Love Canal hazardous-waste site is habitable. An air assessment was conducted for Love Canal Indicator Chemicals. Homes throughout the EDA were sampled using the Trace Atmospheric Gas Analyzer Model 6000E.

  1. Charting the known chemical space for non-aqueous lithium-air battery electrolyte solvents.

    PubMed

    Husch, Tamara; Korth, Martin

    2015-09-21

    Li-air batteries are very promising candidates for powering future mobility, but finding a suitable electrolyte solvent for this technology turned out to be a major problem. We present a systematic computational investigation of the known chemical space for possible Li-air electrolyte solvents. It is shown that the problem of finding better Li-air electrolyte solvents is not only - as previously suggested - about maximizing Li(+) and O2(-) solubilities, but also about finding the optimal balance of these solubilities with the viscosity of the solvent. As our results also show that trial-and-error experiments on known chemicals are unlikely to succeed, full chemical sub-spaces for the most promising compound classes are investigated, and suggestions are made for further experiments. The proposed screening approach is transferable and robust and can readily be applied to optimize electrolytes for other electrochemical devices. It goes beyond the current state-of-the-art both in width (considering the number of compounds screened and the way they are selected), as well as depth (considering the number and complexity of properties included). PMID:26256846

  2. Charting the known chemical space for non-aqueous lithium-air battery electrolyte solvents

    NASA Astrophysics Data System (ADS)

    Husch, Tamara; Korth, Martin

    The Li-Air battery is a very promising candidate for powering future mobility, but finding a suitable electrolyte solvent for this technology turned out to be a major problem. We present a systematic computational investigation of the known chemical space for possible Li-Air electrolyte solvents. It is shown that the problem of finding better Li-Air electrolyte solvents is not only - as previously suggested - about maximizing Li+ and O2- solubilities, but about finding the optimal balance of these solubilities with the viscosity of the solvent. As our results also show that trial-and-error experiments on known chemicals are unlikely to succeed, full chemical sub-spaces for the most promising compound classes are investigated, and suggestions are made for further experiments. The proposed screening approach is transferable and robust and can readily be applied to optimize electrolytes for other electrochemical devices. It goes beyond the current state-of-the-art both in width (considering the number of compounds screened and the way they are selected), as well as depth (considering the number and complexity of properties included).

  3. Chemical process to separate iron oxides particles in pottery sample for EPR dating.

    PubMed

    Watanabe, S; Farias, T M B; Gennari, R F; Ferraz, G M; Kunzli, R; Chubaci, J F D

    2008-12-15

    Ancient potteries usually are made of the local clay material, which contains relatively high concentration of iron. The powdered samples are usually quite black, due to magnetite, and, although they can be used for thermoluminescene (TL) dating, it is easiest to obtain better TL reading when clearest natural or pre-treated sample is used. For electron paramagnetic resonance (EPR) measurements, the huge signal due to iron spin-spin interaction, promotes an intense interference overlapping any other signal in this range. Sample dating is obtained by dividing the radiation dose, determined by the concentration of paramagnetic species generated by irradiation, by the natural dose so as a consequence, EPR dating cannot be used, since iron signal do not depend on radiation dose. In some cases, the density separation method using hydrated solution of sodium polytungstate [Na6(H2W12O40).H2O] becomes useful. However, the sodium polytungstate is very expensive in Brazil; hence an alternative method for eliminating this interference is proposed. A chemical process to eliminate about 90% of magnetite was developed. A sample of powdered ancient pottery was treated in a mixture (3:1:1) of HCl, HNO(3) and H(2)O(2) for 4h. After that, it was washed several times in distilled water to remove all acid matrixes. The original black sample becomes somewhat clearer. The resulting material was analyzed by plasma mass spectrometry (ICP-MS), with the result that the iron content is reduced by a factor of about 9. In EPR measurements a non-treated natural ceramic sample shows a broad spin-spin interaction signal, the chemically treated sample presents a narrow signal in g=2.00 region, possibly due to a radical of (SiO(3))(3-), mixed with signal of remaining iron [M. Ikeya, New Applications of Electron Spin Resonance, World Scientific, Singapore, 1993, p. 285]. This signal increases in intensity under gamma-irradiation. However, still due to iron influence, the additive method yielded too

  4. Chemical characteristics and methane potentials of source-separated and pre-treated organic municipal solid waste.

    PubMed

    Hansen, T L; Svärd, A; Angelidaki, I; Schmidt, J E; Jansen, J; Christensen, T H

    2003-01-01

    A research project has investigated the biogas potential of pre-screened source-separated organic waste. Wastes from five Danish cities have been pre-treated by three methods: screw press; disc screen; and shredder and magnet. This paper outlines the sampling procedure used, the chemical composition of the wastes and the estimated methane potentials. PMID:14531442

  5. Separating the Air Quality Impact of a Major Highway and Nearby Sources by Nonparametric Trajectory Analysis

    EPA Science Inventory

    Nonparametric Trajectory Analysis (NTA), a receptor-oriented model, was used to assess the impact of local sources of air pollution at monitoring sites located adjacent to highway I-15 in Las Vegas, NV. Measurements of black carbon, carbon monoxide, nitrogen oxides, and sulfur di...

  6. PROPERTIES OF DEFATTED AND PIN-MILLED OAT BRAN CONCENTRATE FRACTIONS SEPARATED BY AIR CLASSIFICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oats contain health beneficial beta-glucans. To incorporate into foods, industries seek beta-glucan ingredients with broader functionality. This study investigated the potential for air classification to produce fractionated oat bran products with novel properties. Oat bran concentrate (OBC) was ...

  7. Burst and Principal Components Analyses of MEA Data Separates Chemicals by Class

    EPA Science Inventory

    Microelectrode arrays (MEAs) detect drug and chemical induced changes in action potential "spikes" in neuronal networks and can be used to screen chemicals for neurotoxicity. Analytical "fingerprinting," using Principal Components Analysis (PCA) on spike trains recorded from prim...

  8. Hospital ventilation standards and energy conservation: chemical contamination of hospital air. Final report

    SciTech Connect

    Rainer, D.; Michaelsen, G.S.

    1980-03-01

    In an era of increasing energy conservation consciousness, a critical reassessment of the validity of hospital ventilation and thermal standards is made. If current standards are found to be excessively conservative, major energy conservation measures could be undertaken by rebalancing and/or modification of current HVAC systems. To establish whether or not reducing ventilation rates would increase airborne chemical contamination to unacceptable levels, a field survey was conducted to develop an inventory and dosage estimates of hospital generated airborne chemical contaminants to which patients, staff, and visitors are exposed. The results of the study are presented. Emphasis is on patient exposure, but an examination of occupational exposure was also made. An in-depth assessment of the laboratory air environment is documented. Housekeeping products used in survey hospitals, hazardous properties of housekeeping chemicals and probable product composition are discussed in the appendices.

  9. Development of a method for the regeneration of an alkaline electrolyte in an air-aluminum chemical power supply

    NASA Astrophysics Data System (ADS)

    Pushkin, K. V.; Sevruk, S. D.; Suvorova, E. V.; Farmakovskaya, A. A.

    2015-12-01

    The results of studying the development of a regeneration technology for the spent alkaline electrolyte in an air-aluminum chemical power supply are presented. The application of this technology is a component of the wasteless and friendly environmental operation of an energy installation based on an air-aluminum chemical power supply. The operability of the energy installation based on the air-aluminum chemical power supply using regenerated alkaline electrolytes is experimentally confirmed. Technical requirements for the technological equipment for alkaline electrolyte regeneration are developed on the basis of the obtained results.

  10. Optimization of tomato pomace separation using air aspirator system by response surface methodology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tomato pomace contains seeds and peels which are rich in protein and fat, and dietary fiber and lycopene, respectively. It is important to develop a suitable method to separate seeds and peel in tomato pomace for achieving value-added utilization of tomato pomace. The objectives of this research wer...

  11. Carbon Dioxide Separation Technology: R&D Needs for the Chemical and Petrochemical Industries

    SciTech Connect

    none,

    2007-11-01

    This report, the second in a series, is designed to summarize and present recommendations for improved CO2 separation technology for industrial processes. This report provides an overview of 1) the principal CO2 producing processes, 2) the current commercial separation technologies and 3) emerging adsorption and membrane technologies for CO2 separation, and makes recommendations for future research.

  12. Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System

    SciTech Connect

    Stenner, Robert D.; Hadley, Donald L.; Armstrong, Peter R.; Buck, John W.; Hoopes, Bonnie L.; Janus, Michael C.

    2001-03-01

    Indoor air quality effects on human health are of increasing concern to public health agencies and building owners. The prevention and treatment of 'sick building' syndrome and the spread of air-borne diseases in hospitals, for example, are well known priorities. However, increasing attention is being directed to the vulnerability of our public buildings/places, public security and national defense facilities to terrorist attack or the accidental release of air-borne biological pathogens, harmful chemicals, or radioactive contaminants. The Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System (IA-NBC-HMAS) was developed to serve as a health impact analysis tool for use in addressing these concerns. The overall goal was to develop a user-friendly fully functional prototype Health Modeling and Assessment system, which will operate under the PNNL FRAMES system for ease of use and to maximize its integration with other modeling and assessment capabilities accessible within the FRAMES system (e.g., ambient air fate and transport models, water borne fate and transport models, Physiologically Based Pharmacokinetic models, etc.). The prototype IA-NBC-HMAS is designed to serve as a functional Health Modeling and Assessment system that can be easily tailored to meet specific building analysis needs of a customer. The prototype system was developed and tested using an actual building (i.e., the Churchville Building located at the Aberdeen Proving Ground) and release scenario (i.e., the release and measurement of tracer materials within the building) to ensure realism and practicality in the design and development of the prototype system. A user-friendly "demo" accompanies this report to allow the reader the opportunity for a "hands on" review of the prototype system's capability.

  13. Direct observation of a resolvable spin separation in the spin Hall effect of light at an air-glass interface

    SciTech Connect

    Ren, Jin-Li; Wang, Bo; Xiao, Yun-Feng; Gong, Qihuang; Li, Yan

    2015-09-14

    We theoretically and experimentally demonstrate that it is possible to directly observe the resolvable spin separation in the spin Hall effect of light at an air-glass interface by choosing optimal parameters. When a P-polarized light with a beam waist of 10 μm is incident around Brewster's angle, the two spin components of the reflected beam can be completely separated by eliminating the influence of the in-plane wavevector spread. This not only obviously reveals the strong impacts of the polarization state, the incident angle, the beam waist, and the in-plane wavevector spread, but also intuitively visualizes the observation of the spin Hall effect of light.

  14. Efficient Computation of Separation-Compliant Speed Advisories for Air Traffic Arriving in Terminal Airspace

    NASA Technical Reports Server (NTRS)

    Sadovsky, Alexander V.; Davis, Damek; Isaacson, Douglas R.

    2012-01-01

    A class of problems in air traffic management asks for a scheduling algorithm that supplies the air traffic services authority not only with a schedule of arrivals and departures, but also with speed advisories. Since advisories must be finite, a scheduling algorithm must ultimately produce a finite data set, hence must either start with a purely discrete model or involve a discretization of a continuous one. The former choice, often preferred for intuitive clarity, naturally leads to mixed-integer programs, hindering proofs of correctness and computational cost bounds (crucial for real-time operations). In this paper, a hybrid control system is used to model air traffic scheduling, capturing both the discrete and continuous aspects. This framework is applied to a class of problems, called the Fully Routed Nominal Problem. We prove a number of geometric results on feasible schedules and use these results to formulate an algorithm that attempts to compute a collective speed advisory, effectively finite, and has computational cost polynomial in the number of aircraft. This work is a first step toward optimization and models refined with more realistic detail.

  15. Operational dead air space testing of the chemically protected DEPloyable MEDical Systems (cp DEPMEDS). Final report, Aug-Oct 91

    SciTech Connect

    Seitzinger, A.; Richardson, T.

    1992-07-01

    This report documents the results and findings of dead air space tests on the chemically protected deployable medical systems (DEPMEDS) conducted at Fort Indiantown Gap, PA. The DEPMEDS are composed of various size overpressurized chemically protected shelters connected by viaducts. Designed by the U.S. Army Natick Research, Development and Engineering Center (NATICK), the shelters provide a clean air conditioned atmosphere to treat wounded personnel in a chemical warfare environment. NATICK requested the U.S. Army Chemical Research, Development and Engineering Center's support to identify any dead air spaces, because these spaces would be a potential chemical agent vapor accumulation location, and threaten the collective protection of the shelters. Initially, a smoke generator was utilized to observe the air flow patterns within the DEPMEDS, and suspect dead air space locations were identified. However, subsequent dissemination of sulfur hexafluoride into the ventilation system of the shelter indicated that no dead air spaces were present. This report includes a few suggestions to improve the air circulation of the DEPMEDS, namely elimination of the interior shelter liners and using doors between the viaducts connecting the various shelters. Sulfur, Ventilation kinetics, Shelters, Collective protection, Hexafluoride, Chemical agent simulants.

  16. Chemical reactivities of ambient air samples in three Southern California communities

    PubMed Central

    Eiguren-Fernandez, Arantza; Di Stefano, Emma; Schmitz, Debra A.; Guarieiro, Aline Lefol Nani; Salinas, Erika M.; Nasser, Elina; Froines, John R.; Cho, Arthur K.

    2015-01-01

    The potential adverse health effects of PM2.5 and vapor samples from three communities that neighbor railyards, Commerce (CM), Long Beach (LB), and San Bernardino (SB), were assessed by determination of chemical reactivities attributed to the induction of oxidative stress by air pollutants. The assays used were dithiothreitol (DTT) and dihydrobenzoic acid (DHBA) based procedures for prooxidant content and a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) assay for electrophiles. Prooxidants and electrophiles have been proposed as the reactive chemical species responsible for the induction of oxidative stress by air pollution mixtures. The PM2.5 samples from CM and LB sites showed seasonal differences in reactivities with higher levels in the winter whereas the SB sample differences were reversed. The reactivities in the vapor samples were all very similar, except for the summer SB samples, which contained higher levels of both prooxidants and electrophiles. The results suggest the observed reactivities reflect general geographical differences rather than direct effects of the railyards. Distributional differences in reactivities were also observed with PM2.5 fractions containing most of the prooxidants (74–81%) and the vapor phase most of the electrophiles (82–96%). The high levels of the vapor phase electrophiles and their potential for adverse biological effects point out the importance of the vapor phase in assessing the potential health effects of ambient air. PMID:25947123

  17. High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods.

    PubMed

    Kiddle, G; Bennett, R N; Botting, N P; Davidson, N E; Robertson, A A; Wallsgrove, R M

    2001-01-01

    Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included. PMID:11705329

  18. 30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... openings to the surface— (1) Ventilation tubing approved by MSHA in accordance with 30 CFR part 7 or... for separation of air currents. Such wall or partition shall be constructed of reinforced concrete...

  19. 30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... openings to the surface— (1) Ventilation tubing approved by MSHA in accordance with 30 CFR part 7 or... for separation of air currents. Such wall or partition shall be constructed of reinforced concrete...

  20. 30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... openings to the surface— (1) Ventilation tubing approved by MSHA in accordance with 30 CFR part 7 or... separation of main air currents in the same opening. Flexible ventilation tubing shall not exceed 250 feet...

  1. 30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... openings to the surface— (1) Ventilation tubing approved by MSHA in accordance with 30 CFR part 7 or... separation of main air currents in the same opening. Flexible ventilation tubing shall not exceed 250 feet...

  2. 30 CFR 57.22215 - Separation of intake and return air (I-A, II-A, III, and V-A mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... openings to the surface— (1) Ventilation tubing approved by MSHA in accordance with 30 CFR part 7 or... for separation of air currents. Such wall or partition shall be constructed of reinforced concrete...

  3. In-air spectral signatures of the Baltic Sea macrophytes and their statistical separability

    NASA Astrophysics Data System (ADS)

    Kotta, Jonne; Remm, Kalle; Vahtmäe, Ele; Kutser, Tiit; Orav-Kotta, Helen

    2014-01-01

    Many macroalgal species potentially have distinctive spectral signatures detectable using remote sensing. In order to map the spatial distribution of these species, their spectral properties have to be quantified and statistical differences between species need to be assessed. In the present study, we collected a spectral library of the key benthic macrophyte species in the Baltic Sea area and presented the methodology that allows quantifying statistical differences between their reflectance spectra. The results indicate that three broad groups of algae-green, brown, and red algae-can be separated based on their optical signatures. In general, the between-species differences are too small to allow easy recognition of benthic algae based on their untransformed reflectance spectra. However, the distinctness of the studied species and taxa improves if standardized reflectance values are used. The best indicative spectral range was at 530 to 570 nm for the separation of species and of larger taxonomic units.

  4. Extraction and separation of nickel and cobalt from saprolite laterite ore by microwave-assisted hydrothermal leaching and chemical deposition

    NASA Astrophysics Data System (ADS)

    Zhao, Yan; Gao, Jian-ming; Yue, Yi; Peng, Ben; Que, Zai-qing; Guo, Min; Zhang, Mei

    2013-07-01

    Extraction and separation of nickel and cobalt from saprolite laterite ore were studied by using a method of microwave-assisted hydrothermal leaching and chemical deposition. The effects of leaching temperature and time on the extraction efficiencies of Ni2+ and Co2+ were investigated in detail under microwave conditions. It is shown that the extraction efficiencies of Ni2+ and Co2+ from the ore pre-roasted at 300°C for 5 h were 89.19% and 61.89% when the leaching temperature and time were about 70°C and 60 min, respectively. For the separation process of Ni and Co, the separation of main chemical components was performed by adjusting the pH values of sulfuric leaching solutions using a NaOH solution based on the different pH values of precipitation for metal hydroxides. The final separation efficiencies of Ni and Co were 77.29% and 65.87%, respectively. Furthermore, the separation efficiencies of Fe of 95.36% and Mg of 92.2% were also achieved at the same time.

  5. A multivariate/chemical mass balance model for air pollution in China: A hybrid methodology

    SciTech Connect

    Zelenka, M.P.

    1992-01-01

    This research explores the possibility of using a two step method of identifying and quantifying air pollution emissions in an urban environment. The procedure uses a mathematical model called Target Transformation Factor Analysis (TTFA) to estimate source profiles using ambient trace element air concentration data. A source profile is analogous to a fingerprint since it is unique to each source of air pollution. It is important to use source profiles that are measured or estimated for the specific location under study. The profiles estimated by TTFA are then employed in a Chemical Mass Balance (CMB) source apportionment analysis for the airshed. Other known sources are estimated using source signatures from the literature. Applying the TTFA and CMB models in this fashion is called receptor modeling. Generically, a receptor model is the combination of measured air pollution concentration data with a numerical technique which apportions the measured air pollution among distinct source types. The results show that TTFA can be used to provide quantitative estimates of air pollution source profiles for an urban center in China. The number of profiles for unique source types was limited for this data set since emissions from certain types of sources co-varied during each sampling day. Consequently, the CMB analyses that applied the TTFA source profiles needed to be supplemented with standard US EPA source profiles. The application of TTFA for estimating source profiles from ambient data and the subsequent use of those profiles in CMB analyses with source profiles obtained from the EPA's source library can improve the statistical quality of the source apportionment analysis. TTFA can identify source categories of airborne pollution for specific cities, as well as give quantitative data on the composition of the emissions from those source types.

  6. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    SciTech Connect

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  7. Interdisciplinary approach to assessing the health risk of air toxic chemicals: An overview

    SciTech Connect

    Grose, E.C.; Selgrade, M.J.; Busnell, P.J.; Simmons, J.E.; Allen, J.; McGee, J.; Hauchman, F.; Graham, J.A. )

    1990-10-01

    To assist the regulatory branch of the Environmental Protection Agency in addressing the risk assessment of air toxics, the Health Effects Research Laboratory initiated a comprehensive inhalation toxicology program to provide key health effects data missing from the current data base. A priority ranking of chemicals based on the potential for substantial human exposure and the need for health effects data was developed to identify candidate chemicals for toxicological research. The major goal of the program is to evaluate the concentration-response from acute, intermittent and subchronic inhalation exposures to developmental, genetic, hepatic, immunologic, neurologic, pulmonary and reproductive toxicity in a manner that provides data for the regulatory health assessment of air toxic chemicals. Extrapolation and dosimetry research is also conducted to improve the basis for human risk assessment. Determination of biological endpoints to be examined will be decided on a compound-by-compound basis, depending on the physical, chemical and structural characteristics of the chemical and evaluation of the existing health data base. Although the main emphasis is on inhalation as the primary route of exposure, some of the laboratories will compare inhalation to other routes, such as oral, to better understand the influence of route of exposure and hence the potential applicability of existing health data. Acute and intermittent exposures will be done for all compounds. Upon evaluation of the acute results, a decision will be made as to whether subchronic studies are needed. Endpoints that show unusual sensitivity may be investigated in greater detail. If adverse effects are observed at ambient levels, the time to recovery after exposure will be investigated. 36 refs.

  8. Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract.

    PubMed

    Lakey, Pascale S J; Berkemeier, Thomas; Tong, Haijie; Arangio, Andrea M; Lucas, Kurt; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-01-01

    Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air. PMID:27605301

  9. Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract

    PubMed Central

    Lakey, Pascale S. J.; Berkemeier, Thomas; Tong, Haijie; Arangio, Andrea M.; Lucas, Kurt; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-01-01

    Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air. PMID:27605301

  10. Chemical Vapor Deposition of MoS2: Insight Into the Growth Mechanism by Separated Gas Flow Experiments.

    PubMed

    Yanase, Takashi; Watanabe, Sho; Weng, Mengting; Nagahama, Taro; Shimada, Toshihiro

    2016-04-01

    We report detailed experiments on chemical vapor deposition of an atomic' layer semiconductor MoS2. We developed a new type of CVD system in which MoO3 and S sources are separately supplied to the substrates. It has become possible to precisely control the supply of the materials separately in the order of seconds. Raman and XPS analysis of the films grown under various conditions revealed that the initially obtained films are S-deficient and complete stoichiometry is reached after several minutes under S vapor flow. PMID:27451608

  11. MODIFICATION AND EVALUATION OF A HIGH-VOLUME AIR SAMPLER FOR PESTICIDES AND SEMIVOLATILE INDUSTRIAL ORGANIC CHEMICALS

    EPA Science Inventory

    Previously we reported the development and evaluation of a high-volume air sampler for pesticides and other semivolatile industrial organic chemicals (1). This sampler has proved useful for monitoring airborne pesticides associated with agricultural applications (2) and polychlor...

  12. Hydrodynamic Modeling of Air Blast Propagation from the Humble Redwood Chemical High Explosive Detonations Using GEODYN

    SciTech Connect

    Chipman, V D

    2011-09-20

    Two-dimensional axisymmetric hydrodynamic models were developed using GEODYN to simulate the propagation of air blasts resulting from a series of high explosive detonations conducted at Kirtland Air Force Base in August and September of 2007. Dubbed Humble Redwood I (HR-1), these near-surface chemical high explosive detonations consisted of seven shots of varying height or depth of burst. Each shot was simulated numerically using GEODYN. An adaptive mesh refinement scheme based on air pressure gradients was employed such that the mesh refinement tracked the advancing shock front where sharp discontinuities existed in the state variables, but allowed the mesh to sufficiently relax behind the shock front for runtime efficiency. Comparisons of overpressure, sound speed, and positive phase impulse from the GEODYN simulations were made to the recorded data taken from each HR-1 shot. Where the detonations occurred above ground or were shallowly buried (no deeper than 1 m), the GEODYN model was able to simulate the sound speeds, peak overpressures, and positive phase impulses to within approximately 1%, 23%, and 6%, respectively, of the actual recorded data, supporting the use of numerical simulation of the air blast as a forensic tool in determining the yield of an otherwise unknown explosion.

  13. Evaluating the performance of low cost chemical sensors for air pollution research.

    PubMed

    Lewis, Alastair C; Lee, James D; Edwards, Peter M; Shaw, Marvin D; Evans, Mat J; Moller, Sarah J; Smith, Katie R; Buckley, Jack W; Ellis, Matthew; Gillot, Stefan R; White, Andrew

    2016-07-18

    Low cost pollution sensors have been widely publicized, in principle offering increased information on the distribution of air pollution and a democratization of air quality measurements to amateur users. We report a laboratory study of commonly-used electrochemical sensors and quantify a number of cross-interferences with other atmospheric chemicals, some of which become significant at typical suburban air pollution concentrations. We highlight that artefact signals from co-sampled pollutants such as CO2 can be greater than the electrochemical sensor signal generated by the measurand. We subsequently tested in ambient air, over a period of three weeks, twenty identical commercial sensor packages alongside standard measurements and report on the degree of agreement between references and sensors. We then explore potential experimental approaches to improve sensor performance, enhancing outputs from qualitative to quantitative, focusing on low cost VOC photoionization sensors. Careful signal handling, for example, was seen to improve limits of detection by one order of magnitude. The quantity, magnitude and complexity of analytical interferences that must be characterised to convert a signal into a quantitative observation, with known uncertainties, make standard individual parameter regression inappropriate. We show that one potential solution to this problem is the application of supervised machine learning approaches such as boosted regression trees and Gaussian processes emulation. PMID:27104223

  14. Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste

    SciTech Connect

    Okada, Takashi; Tomikawa, Hiroki

    2013-03-15

    Highlights: ► Separation of Pb and Zn from Fe and Cu in ash-melting of municipal solid waste. ► Molar ratio of Cl to Na and K in fly ash affected the metal-separation efficiency. ► The low molar ratio and a non-oxidative atmosphere were better for the separation. - Abstract: In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of the ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu.

  15. Separating the air quality impact of a major highway and nearby sources by nonparametric trajectory analysis.

    PubMed

    Henry, Ronald C; Vette, Alan; Norris, Gary; Vedantham, Ram; Kimbrough, Sue; Shores, Richard C

    2011-12-15

    Nonparametric Trajectory Analysis (NTA), a receptor-oriented model, was used to assess the impact of local sources of air pollution at monitoring sites located adjacent to highway I-15 in Las Vegas, NV. Measurements of black carbon, carbon monoxide, nitrogen oxides, and sulfur dioxide concentrations were collected from December 2008 to December 2009. The purpose of the study was to determine the impact of the highway at three downwind monitoring stations using an upwind station to measure background concentrations. NTA was used to precisely determine the contribution of the highway to the average concentrations measured at the monitoring stations accounting for the spatially heterogeneous contributions of other local urban sources. NTA uses short time average concentrations, 5 min in this case, and constructed local back-trajectories from similarly short time average wind speed and direction to locate and quantify contributions from local source regions. Averaged over an entire year, the decrease of concentrations with distance from the highway was found to be consistent with previous studies. For this study, the NTA model is shown to be a reliable approach to quantify the impact of the highway on local air quality in an urban area with other local sources. PMID:22044064

  16. A female pelvic bone shape model for air/bone separation in support of synthetic CT generation for radiation therapy.

    PubMed

    Liu, Lianli; Cao, Yue; Fessler, Jeffrey A; Jolly, Shruti; Balter, James M

    2016-01-01

    Separating bone from air in MR data is one of the major challenges in using MR images to derive synthetic CT. The problem is further complicated when the anatomic regions filled with air are altered across scans due to air mobility, for instance, in pelvic regions, thereby the air regions estimated using an ultrashort echo time (UTE) sequence are invalid in other image series acquired for multispectral classification. This study aims to develop and investigate a female pelvic bone shape model to identify low intensity regions in MRI where air is unlikely to be present in support of synthetic CT generation without UTE imaging. CT scans of 30 patients were collected for the study, 17 of them also have corresponding MR scans. The shape model was built from the CT dataset, where the reference image was aligned to each of the training images using B-spline deformable registration. Principal component analysis was performed on B-spline coefficients for a compact model where shape variance was described by linear combination of principal modes. The model was applied to identify pelvic bone in MR images by deforming the corresponding MR data of the reference image to target MR images, where the search space of the deformation process was constrained within the subspace spanned by principal modes. The local minima in the search space were removed effectively by the shape model, thus supporting an efficient binary search for the optimal solution. We evaluated the model by its efficacy in identifying bone voxels and excluding air regions. The model was tested across the 17 patients that have corresponding MR scans using a leave-one-out cross validation. A simple model using the first leading principal mode only was found to achieve reasonable accuracy, where an averaged 87% of bone voxels were correctly identified. Finally dilation of the optimally fit bone mask by 5 mm was found to cover 96% of bone voxels while minimally impacting the overlap with air (below 0.4%). PMID

  17. 40 CFR Table 1 to Subpart Vvvvvv... - Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 14 2011-07-01 2011-07-01 false Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations 1 Table 1 to Subpart VVVVVV of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  18. 40 CFR Table 1 to Subpart Vvvvvv... - Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 15 2012-07-01 2012-07-01 false Hazardous Air Pollutants Used To Determine Applicability of Chemical Manufacturing Operations 1 Table 1 to Subpart VVVVVV of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED)...

  19. Application of pervaporation and vapor permeation processes to separate aqueous ethanol solution through chemically modified Nylon 4 membranes

    SciTech Connect

    Wang, Y.H.; Teng, M.Y.; Lee, K.R.; Wang, D.M.; Lai, J.Y.

    1998-08-01

    The pervaporation performance of a Nylon 4 membrane, chemically grafted by N,N-dimethylaminoethyl methacrylate (DMAEM), DMAEM-g-N4, was studied by measurement of the permeation ratio and the pervaporation separation index. It was found that the water permselectivity and permeation rate for the chemically modified Nylon 4 membrane were higher than those of the unmodified Nylon 4 membrane. Optimum pervaporation results, a separation factor of 28.3, and a permeation rate of 439 g/m{sup 2}{center_dot}h, were obtained when the degree of grafting was 12.7%. It was also found that all the permeation ratios at low temperature were less than unity. In addition, compared with pervaporation, vapor permeation effectively increases the permselectivity of water.

  20. Chemically modified polymeric resins for high performance liquid chromatography, solid-phase extraction and organic separation by LC and GC

    SciTech Connect

    Sun, Jeffrey Jiafang.

    1991-08-06

    Polystyrene divinylbenzene resins were chemically modified by introduction of various functional groups, which included polar, non-polar, ionic and metallic groups. These chemically modified polymeric resins were used successfully for high performance liquid chromatography, solid phase extraction and some special applications in liquid and gas chromatography. The introduced functional groups offer an additional selectivity parameter for liquid chromatographic separation. The polar derivatized polymeric resins dramatically increased the recoveries of solid phase extraction, especially for polar compounds. The sulfonated polystyrene resins were used for separation of neutral and basic compounds as well as basic and weaker basic compounds. The sulfonated non-porous resin was used amine abstracter and the polymeric-mercuric resin was used as mercaptan abstracter in capillary gas chromatograph. The researches in this dissertation has shown the very promising applications of polystyrene divinylbenzene resin in chromatographic field. 58 refs., 34 figs., 28 tabs.

  1. Sensitivity and Uncertainty Analysis in Chemical Mechanisms for Air Quality Modeling

    NASA Astrophysics Data System (ADS)

    Gao, Dongfen

    1995-01-01

    Ambient ozone in urban and regional air pollution is a serious environmental problem. Air quality models can be used to predict ozone concentrations and explore control strategies. One important component of such air quality models is a chemical mechanism. Sensitivity and uncertainty analysis play an important role in the evaluation of the performance of air quality models. The uncertainties associated with the RADM2 chemical mechanism in predicted concentrations of O_3, HCHO, H _2rm O_2, PAN, and HNO _3 were estimated. Monte Carlo simulations with Latin Hypercube Sampling were used to estimate the overall uncertainties in concentrations of species of interest, due to uncertainties in chemical parameters. The parameters that were treated as random variables were identified through first-order sensitivity and uncertainty analyses. Recent estimates of uncertainties in rate parameters and product yields were used. The results showed the relative uncertainties in ozone predictions are +/-23-50% (1sigma relative to the mean) in urban cases, and less than +/-20% in rural cases. Uncertainties in HNO_3 concentrations are the smallest, followed by HCHO, O_3 and PAN. Predicted H_2rm O_2 concentrations have the highest uncertainties. Uncertainties in the differences of peak ozone concentrations between base and control cases were also studied. The results show that the uncertainties in the fractional reductions in ozone concentrations were 9-12% with NO_{rm x} control at an ROG/NO_{rm x} ratio of 24:1 and 11-33% with ROG control at an ROG/NO _{rm x} ratio of 6:1. Linear regression analysis of the Monte Carlo results showed that uncertainties in rate parameters for the formation of HNO_3, for the reaction of HCHO + hv to 2HO _2 + CO, for PAN chemistry and for the photolysis of NO_2 are most influential to ozone concentrations and differences of ozone. The parameters that are important to ozone concentrations also tend to be relatively influential to other key species

  2. Method for the chemical separation of GE-68 from its daughter Ga-68

    DOEpatents

    Fitzsimmons, Jonathan M.; Atcher, Robert W.

    2010-06-01

    The present invention is directed to a generator apparatus for separating a daughter gallium-68 radioisotope substantially free of impurities from a parent gernanium-68 radioisotope, including a first resin-containing column containing parent gernanium-68 radioisotope and daughter gallium-68 radioisotope, a source of first eluent connected to said first resin-containing column for separating daughter gallium-68 radioisotope from the first resin-containing column, said first eluent including citrate whereby the separated gallium is in the form of gallium citrate, a mixing space connected to said first resin-containing column for admixing a source of hydrochloric acid with said separated gallium citrate whereby gallium citrate is converted to gallium tetrachloride, a second resin-containing column for retention of gallium-68 tetrachloride, and, a source of second eluent connected to said second resin-containing column for eluting the daughter gallium-68 radioisotope from said second resin-containing column.

  3. Development of New Generation of Ceramics for Environmentally Focused Chemical Separations

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Girish

    This dissertation focuses on the use of composite materials for environmental applications. For the first time, applications of both fresh and aged concrete as inexpensive adsorbents for nitrogen dioxide (NO2) removal is demonstrated. Concrete is the most widely used composite material of the modern era. Cement manufacturing (a major component of concrete) is considered to be one of the leading contributors to air pollution, resulting in 7% of the global carbon dioxide emissions along with a number of other harmful pollutants such as oxides, mercury and particulates. These emissions aide in the formation of acid rain, smog, and toxic ground level ozone, causing detrimental effects such as respiratory illnesses, visibility reduction, eutrification and global warming. This thesis offers a novel and sustainable solution in mitigating NOX emissions, by introducing the significant adsorption potential of recycled concrete. The work is based on both commercially available cement paste and already aged concrete samples, providing truly scalable solutions. The concrete samples aged for different periods of time were exposed to NO2 to measure their adsorption capacity. The results show that all of the concrete samples (fresh and aged) exhibited excellent NO2 adsorption capacity, with the fresh concrete samples removing almost 100% of the NO2. Furthermore, to compare the effects of long term aging, 12 year-old recently demolished concrete samples were obtained and its NOX removal was shown to be almost 60%. The experimental results provide evidence of nitrate and nitrite species formation from chemical reactions occurring between NO2 and surface alkaline species. This important discovery can be utilized for NO2 removal and subsequent NOX sequestered demolished concrete (NSDC) recycling in new concrete, either as a set accelerating admixture or as a corrosion inhibitor, a big leap towards better sustainability and longevity of the new reinforced concrete structures. The rest

  4. Investigating the Complexity of Transitioning Separation Assurance Tools into NextGen Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Gomez, Ashley Nicole; Martin, Lynne Hazel; Homola, Jeffrey; Morey, Susan; Cabrall, Christopher; Mercer, Joey; Prevot, Thomas

    2013-01-01

    In a study, that introduced ground-based separation assurance automation through a series of envisioned transitional phases of concept maturity, it was found that subjective responses to scales of workload, situation awareness, and acceptability in a post run questionnaire revealed as-predicted results for three of the four study conditions but not for the third, Moderate condition. The trend continued for losses of separation (LOS) where the number of LOS events were far greater than expected in the Moderate condition. To offer an account of why the Moderate condition was perceived to be more difficult to manage than predicted, researchers examined the increase in amount and complexity of traffic, increase in communication load, and increased complexities as a result of the simulation's mix of aircraft equipage. Further analysis compared the tools presented through the phases, finding that controllers took advantage of the informational properties of the tools presented but shied away from using their decision support capabilities. Taking into account similar findings from other studies, it is suggested that the Moderate condition represented the first step into a "shared control" environment, which requires the controller to use the automation as a decision making partner rather than just a provider of information. Viewed in this light, the combination of tools offered in the Moderate condition was reviewed and some tradeoffs that may offset the identified complexities were suggested.

  5. Radar Inaccuracies and Mid-Air Collision Risk: Part 2 En Route Radar Separation Minima

    NASA Astrophysics Data System (ADS)

    Brooker, Peter

    2004-01-01

    A review of safety targets for en route ATC radar separation suggests that the existing target level of safety (TLS) is over-cautious. If risk budgeting principles are followed consistently, a ‘radar TLS’ of 1·0×10[minus sign]9 fatal aircraft accidents per flying hour is appropriate. This rate is consistent with Joint Aviation Authorities (JAA) guidance on system failure conditions leading to catastrophic accidents. Dynamic and static calculations using published data are compared. The new methodology shows where there are problems with the traditional static calculations, and how to improve the estimation. A further improvement introduces a simple robust model of the controller's decision processes. The focus is not on describing what controllers would generally do, but on setting criteria based on what they could not reasonably be expected to do. This additional ingredient into the calculation adds realism and ensures that attention is focused on hazardous correlated errors. Focused data collection would be an essential component of new risk estimates. The key information required would be on radar performance and the nature and frequency of use of radar separation, including the relative velocities for proximate events at closest point of approach and the frequency of correlated gross errors (through a conditional probability factor). If this factor is not properly taken into account, then the data collection and analysis could be inefficient.

  6. Wind tunnel experiments on flow separation control of an Unmanned Air Vehicle by nanosecond discharge plasma aerodynamic actuation

    NASA Astrophysics Data System (ADS)

    Kang, Chen; Hua, Liang

    2016-02-01

    Plasma flow control (PFC) is a new kind of active flow control technology, which can improve the aerodynamic performances of aircrafts remarkably. The flow separation control of an unmanned air vehicle (UAV) by nanosecond discharge plasma aerodynamic actuation (NDPAA) is investigated experimentally in this paper. Experimental results show that the applied voltages for both the nanosecond discharge and the millisecond discharge are nearly the same, but the current for nanosecond discharge (30 A) is much bigger than that for millisecond discharge (0.1 A). The flow field induced by the NDPAA is similar to a shock wave upward, and has a maximal velocity of less than 0.5 m/s. Fast heating effect for nanosecond discharge induces shock waves in the quiescent air. The lasting time of the shock waves is about 80 μs and its spread velocity is nearly 380 m/s. By using the NDPAA, the flow separation on the suction side of the UAV can be totally suppressed and the critical stall angle of attack increases from 20° to 27° with a maximal lift coefficient increment of 11.24%. The flow separation can be suppressed when the discharge voltage is larger than the threshold value, and the optimum operation frequency for the NDPAA is the one which makes the Strouhal number equal one. The NDPAA is more effective than the millisecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect in high speed flow control. Project supported by the National Natural Science Foundation of China (Grant Nos. 61503302, 51207169, and 51276197), the China Postdoctoral Science Foundation (Grant No. 2014M562446), and the Natural Science Foundation of Shaanxi Province, China (Grant No. 2015JM1001).

  7. Air-activated chemical warming devices: effects of oxygen and pressure.

    PubMed

    Raleigh, G; Rivard, R; Fabus, S

    2005-01-01

    Air-activated chemical warming devices use an exothermic chemical reaction of rapidly oxidizing iron to generate heat for therapeutic purposes. Placing these products in a hyperbaric oxygen environment greatly increases the supply of oxidant and thus increases the rate of reaction and maximum temperature. Testing for auto-ignition and maximum temperatures attained by ThermaCare Heat Wraps, Playtex Heat Therapy, and Heat Factory disposable warm packs under ambient conditions and under conditions similar to those encountered during hyperbaric oxygen treatments in monoplace and multiplace hyperbaric chambers (3 atm abs and > 95% oxygen) revealed a maximum temperature of 269 degrees F (132 degrees C) with no spontaneous ignition. The risk of thermal burn injury to adjacent skin may be increased significantly if these devices are used under conditions of hyperbaric oxygen. PMID:16509287

  8. Conservation equations and physical models for hypersonic air flows in thermal and chemical nonequilibrium

    SciTech Connect

    Gnoffo, P.A.; Gupta, R.N.; Shinn, J.L.

    1989-02-01

    The conservation equations for simulating hypersonic flows in thermal and chemical nonequilibrium and details of the associated physical models are presented. These details include the curve fits used for defining thermodynamic properties of the 11 species air model, curve fits for collision cross sections, expressions for transport properties, the chemical kinetics models, and the vibrational and electronic energy relaxation models. The expressions are formulated in the context of either a two or three temperature model. Greater emphasis is placed on the two temperature model in which it is assumed that the translational and rotational energy models are in equilibrium at the translational temperature, T, and the vibrational, electronic, and electron translational energy modes are in equilibrium at the vibrational temperature, T sub v. The eigenvalues and eigenvectors associated with the Jacobian of the flux vector are also presented in order to accommodate the upwind based numerical solutions of the complete equation set.

  9. Conservation equations and physical models for hypersonic air flows in thermal and chemical nonequilibrium

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Gupta, Roop N.; Shinn, Judy L.

    1989-01-01

    The conservation equations for simulating hypersonic flows in thermal and chemical nonequilibrium and details of the associated physical models are presented. These details include the curve fits used for defining thermodynamic properties of the 11 species air model, curve fits for collision cross sections, expressions for transport properties, the chemical kinetics models, and the vibrational and electronic energy relaxation models. The expressions are formulated in the context of either a two or three temperature model. Greater emphasis is placed on the two temperature model in which it is assumed that the translational and rotational energy models are in equilibrium at the translational temperature, T, and the vibrational, electronic, and electron translational energy modes are in equilibrium at the vibrational temperature, T sub v. The eigenvalues and eigenvectors associated with the Jacobian of the flux vector are also presented in order to accommodate the upwind based numerical solutions of the complete equation set.

  10. Chemical species separation with simultaneous estimation of field map and T2* using a k-space formulation.

    PubMed

    Honorato, Jose Luis; Parot, Vicente; Tejos, Cristian; Uribe, Sergio; Irarrazaval, Pablo

    2012-08-01

    Chemical species separation techniques in image space are prone to incorporate several distortions. Some of these are signal accentuation in borders and geometrical warping from field inhomogeneity. These errors come from neglecting intraecho time variations. In this work, we present a new approach for chemical species separation in MRI with simultaneous estimation of field map and T2* decay, formulated entirely in k-space. In this approach, the time map is used to model the phase accrual from off-resonance precession and also the amplitude decay due to T2*. Our technique fits the signal model directly in k-space with the acquired data minimizing the l(2)-norm with an interior-point algorithm. Standard two dimensional gradient echo sequences in the thighs and head were used for demonstrating the technique. With this approach, we were able to obtain excellent estimation for the species, the field inhomogeneity, and T2* decay images. The results do not suffer from geometric distortions derived from the chemical shift or the field inhomogeneity. Importantly, as the T2* map is well positioned, the species signal in borders is correctly estimated. Considering intraecho time variations in a complete signal model in k-space for separating species yields superior estimation of the variables of interest when compared to existing methods. PMID:22212998

  11. Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste.

    PubMed

    Okada, Takashi; Tomikawa, Hiroki

    2013-03-01

    In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of the ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu. PMID:22981781

  12. Separation of Corn Fiber and Conversion to Fuels and Chemicals: Pilot-Scale Operation

    SciTech Connect

    2006-04-01

    This project focuses on the development and pilot-scale testing of technologies that will enable the development of a biorefinery capable of economically deriving high-value chemicals and oils from lower value corn fiber.

  13. Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

    NASA Technical Reports Server (NTRS)

    Glass, Christopher E.

    1990-01-01

    The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

  14. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath

    PubMed Central

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-01-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising. PMID:27160439

  15. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath

    NASA Astrophysics Data System (ADS)

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-05-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising.

  16. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath.

    PubMed

    Williams, Jonathan; Stönner, Christof; Wicker, Jörg; Krauter, Nicolas; Derstroff, Bettina; Bourtsoukidis, Efstratios; Klüpfel, Thomas; Kramer, Stefan

    2016-01-01

    Human beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely "suspense" or "comedy" caused audiences to change their emission of specific chemicals. These event-type synchronous, broadcasted human chemosignals open the possibility for objective and non-invasive assessment of a human group response to stimuli by continuous measurement of chemicals in air. Such methods can be applied to research fields such as psychology and biology, and be valuable to industries such as film making and advertising. PMID:27160439

  17. Interdisciplinary Learning for Chemical Engineering Students from Organic Chemistry Synthesis Lab to Reactor Design to Separation

    ERIC Educational Resources Information Center

    Armstrong, Matt; Comitz, Richard L.; Biaglow, Andrew; Lachance, Russ; Sloop, Joseph

    2008-01-01

    A novel approach to the Chemical Engineering curriculum sequence of courses at West Point enabled our students to experience a much more realistic design process, which more closely replicated a real world scenario. Students conduct the synthesis in the organic chemistry lab, then conduct computer modeling of the reaction with ChemCad and…

  18. Reversible swarming and separation of self-propelled chemically powered nanomotors under acoustic fields.

    PubMed

    Xu, Tailin; Soto, Fernando; Gao, Wei; Dong, Renfeng; Garcia-Gradilla, Victor; Magaña, Ernesto; Zhang, Xueji; Wang, Joseph

    2015-02-18

    The collective behavior of biological systems has inspired efforts toward the controlled assembly of synthetic nanomotors. Here we demonstrate the use of acoustic fields to induce reversible assembly of catalytic nanomotors, controlled swarm movement, and separation of different nanomotors. The swarming mechanism relies on the interaction between individual nanomotors and the acoustic field, which triggers rapid migration and assembly around the nearest pressure node. Such on-demand assembly of catalytic nanomotors is extremely fast and reversible. Controlled movement of the resulting swarm is illustrated by changing the frequency of the acoustic field. Efficient separation of different types of nanomotors, which assemble in distinct swarming regions, is illustrated. The ability of acoustic fields to regulate the collective behavior of catalytic nanomotors holds considerable promise for a wide range of practical applications. PMID:25634724

  19. Flow processes in overexpanded chemical rocket nozzles. Part 2: Side loads due to asymmetric separation

    NASA Technical Reports Server (NTRS)

    Schmucker, R. H.

    1984-01-01

    Methods for measuring the lateral forces, occurring as a result of asymmetric nozzle flow separation, are discussed. The effect of some parameters on the side load is explained. A new method was developed for calculation of the side load. The values calculated are compared with side load data of the J-2 engine. Results are used for predicting side loads of the space shuttle main engine.

  20. Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer.

    PubMed

    Smith, Jonell N; Noll, Robert J; Cooks, R Graham

    2011-05-30

    Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components. PMID:21504010

  1. Technology of oxygen production in the membranecryogenic air separation system for a 600 MW oxy-type pulverized bed boiler

    NASA Astrophysics Data System (ADS)

    Berdowska, Sylwia; Skorek-Osikowska, Anna

    2012-09-01

    In this paper the results of the thermodynamic analysis of the oxy-combustion type pulverized bed boiler integrated with a hybrid, membrane- cryogenic oxygen separation installation are presented. For the calculations a 600 MW boiler with live steam parameters at 31.1 MPa /654.9 oC and reheated steam at 6.15 MPa/672.4 oC was chosen. In this paper the hybrid membrane-cryogenic technology as oxygen production unit for pulverized bed boiler was proposed. Such an installation consists of a membrane module and two cryogenic distillation columns. Models of these installations were built in the Aspen software. The energy intensity of the oxygen production process in the hybrid system was compared with the cryogenic technology. The analysis of the influence of membrane surface area on the energy intensity of the process of air separation as well as the influence of oxygen concentration at the inlet to the cryogenic installation on the energy intensity of a hybrid unit was performed.

  2. Bio-electrochemical characterization of air-cathode microbial fuel cells with microporous polyethylene/silica membrane as separator.

    PubMed

    Kircheva, Nina; Outin, Jonathan; Perrier, Gérard; Ramousse, Julien; Merlin, Gérard; Lyautey, Emilie

    2015-12-01

    The aim of this work was to study the behavior over time of a separator made of a low-cost and non-selective microporous polyethylene membrane (RhinoHide®) in an air-cathode microbial fuel cell with a reticulated vitreous carbon foam bioanode. Performances of the microporous polyethylene membrane (RhinoHide®) were compared with Nafion®-117 as a cationic exchange membrane. A non-parametric test (Mann-Whitney) done on the different sets of coulombic or energy efficiency data showed no significant difference between the two types of tested membrane (p<0.05). Volumetric power densities were ranging from 30 to 90 W·m(-3) of RVC foam for both membranes. Similar amounts of biomass were observed on both sides of the polyethylene membrane illustrating bacterial permeability of this type of separator. A monospecific denitrifying population on cathodic side of RhinoHide® membrane has been identified. Electrochemical impedance spectroscopy (EIS) was used at OCV conditions to characterize electrochemical behavior of MFCs by equivalent electrical circuit fitted on both Nyquist and Bode plots. Resistances and pseudo-capacitances from EIS analyses do not differ in such a way that the nature of the membrane could be considered as responsible. PMID:26073676

  3. The Relationship between the Hydrophilicity and Surface Chemical Composition Microphase Separation Structure of Multicomponent Silicone Hydrogels.

    PubMed

    Zhao, Zheng-Bai; An, Shuang-Shuang; Xie, Hai-Jiao; Han, Xue-Lian; Wang, Fu-He; Jiang, Yong

    2015-07-30

    Three series of multicomponent silicone hydrogels were prepared by the copolymerization of two hydrophobic silicon monomers bis(trimethylsilyloxy) methylsilylpropyl glycerol methacrylate (SiMA) and tris(trimethylsiloxy) 3-methacryloxypropylsilane (TRIS) with three hydrophilic monomers. The surface hydrophilicity of the silicone hydrogels was characterized by contact angle measurements, and an interesting phenomenon was found that the silicone hydrogels made from less hydrophobic monomer SiMA possess more hydrophobic surfaces than those made from TRIS. The surface properties such as morphology and elemental composition of the silicone hydrogels were explored by scanning electron microscopy (SEM) imaging and energy dispersive spectrometry (EDS) analysis, and their relationships with the surface hydrophilicity were investigated in details. The results show neither the surface morphology nor the elemental composition has obvious impact on the surface hydrophilicity. Atomic force microscopy (AFM) imaging revealed that SiMA hydrogel had a more significant phase separation structure, which also made its surface uneven: a lot of tiny holes were observed on the surface. This surface phase separation structure made SiMA hydrogel more difficult to be wetted by water or PBS buffer, i.e., more hydrophobic than TRIS hydrogel. On the basis of these results, we propose that the phase separation structure as well as the nature of silicon monomers might be the fundamental reasons of surface hydrophilicity. These results could help to design a silicone hydrogel with better surface properties and wider application. PMID:26125331

  4. Modeling the uptake of neutral organic chemicals on XAD passive air samplers under variable temperatures, external wind speeds and ambient air concentrations (PAS-SIM).

    PubMed

    Armitage, James M; Hayward, Stephen J; Wania, Frank

    2013-01-01

    The main objective of this study was to evaluate the performance and demonstrate the utility of a fugacity-based model of XAD passive air samplers (XAD-PAS) designed to simulate the uptake of neutral organic chemicals under variable temperatures, external wind speeds and ambient air concentrations. The model (PAS-SIM) simulates the transport of the chemical across the air-side boundary layer and within the sampler medium, which is segmented into a user-defined number of thin layers. Model performance was evaluated using data for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from a field calibration study (i.e., active and XAD-PAS data) conducted in Egbert, Ontario, Canada. With some exceptions, modeled PAS uptake curves are in good agreement with the empirical PAS data. The results are highly encouraging, given the uncertainty in the active air sampler data used as input and other uncertainties related to model parametrization (e.g., sampler-air partition coefficients, the influence of wind speed on sampling rates). The study supports the further development and evaluation of the PAS-SIM model as a diagnostic (e.g., to aid interpretation of calibration studies and monitoring data) and prognostic (e.g., to inform design of future passive air sampling campaigns) tool. PMID:24175752

  5. Estimated Performance of Radial-Flow Exit Nozzles for Air in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Englert, Gerald W.; Kochendorfer, Fred D.

    1959-01-01

    The thrust, boundary-layer, and heat-transfer characteristics were computed for nozzles having radial flow in the divergent part. The working medium was air in chemical equilibrium, and the boundary layer was assumed to be all turbulent. Stagnation pressure was varied from 1 to 32 atmospheres, stagnation temperature from 1000 to 6000 R, and wall temperature from 1000 to 3000 R. Design pressure ratio was varied from 5 to 320, and operating pressure ratio was varied from 0.25 to 8 times the design pressure ratio. Results were generalized independent of divergence angle and were also generalized independent of stagnation pressure in the temperature range of 1000 to 3000 R. A means of determining the aerodynamically optimum wall angle is provided.

  6. Coupled Physical/Chemical and Biofiltration Technologies to Reduce Air Emissions from Forest Products Industries

    SciTech Connect

    Gary D. McGinnis

    2001-12-31

    The research is a laboratory and bench-scale investigation of a system to concentrate and destroy volatile organic compounds (VOCs), including hazardous air pollutants, formed from the drying of wood and the manufacture of wood board products (e.g., particle board and oriented strandboard). The approach that was investigated involved concentrating the dilute VOCs (<500 ppmv) with a physical/chemical adsorption unit, followed by the treatment of the concentrated voc stream (2,000 to 2,500 ppmv) with a biofiltration unit. The research program lasted three years, and involved three research organizations. Michigan Technological University was the primary recipient of the financial assistance, the USDA Forest Products Laboratory (FPL) and Mississippi State University (MSU) were subcontractors to MTU. The ultimate objective of this research was to develop a pilot-scale demonstration of the technology with sufficient data to provide for the design of an industrial system. No commercialization activities were included in this project.

  7. Cultivation and recovery of vascular endothelial cells in microchannels of a separable micro-chemical chip.

    PubMed

    Yamashita, Tadahiro; Tanaka, Yo; Idota, Naokazu; Sato, Kae; Mawatari, Kazuma; Kitamori, Takehiko

    2011-04-01

    Various micro cell culture systems have recently been developed. However, it is extremely difficult to recover cultured cells from a microchannel because the upper and lower substrates of a microchip are permanently combined. Therefore, we developed a cell culture and recovery system that uses a separable microchip with reversible combining that allows separation between closed and open channels. To realize this system, two problems related to microfluidic control-prevention of leakage and non-invasive recovery of cultured cells from the substrate-must be overcome. In the present study, we used surface chemistry modification to solve both problems. First, octadecyltrimethoxysilane (ODTMS) was utilized to control the Laplace pressure at the liquid/vapor phase interface, such that it was directed toward the microchannels, which suppressed leakage from the slight gap between two substrates. Second, a thermoresponsive polymer poly(N-isopropyl acrylamide) (PNIPAAm) was used to coat the surface of the ODTMS-modified microchannel by UV-mediated photopolymerization. PNIPAAm substrates are well known for controlled cell adhesion/detachment by alteration of temperature. Finally, the ODTMS- and PNIPAAm-modified separable microchips were subjected to patterning, and human arterial endothelial cells (HAECs) were cultured in the resulting microchannels with no leakage. After 96 h of the culture, the HAECs were detached from the microchips by decreasing the temperature and were then recovered from the microchannels. This study is the first to demonstrate the recovery of living cells cultured in a microchannel, and may be useful as a fundamental technique for vascular tissue engineering. PMID:21251708

  8. Incorporating Detailed Chemical Characterization of Biomass Burning Emissions into Air Quality Models

    NASA Astrophysics Data System (ADS)

    Barsanti, K.; Hatch, L. E.; Yokelson, R. J.; Stockwell, C.; Orlando, J. J.; Emmons, L. K.; Knote, C. J.; Wiedinmyer, C.

    2015-12-01

    Approximately 500 Tg/yr of non-methane organic compounds (NMOCs) are emitted by biomass burning (BB) to the global atmosphere, leading to the photochemical production of ozone (O3) and secondary particulate matter (PM). Until recently, in studies of BB emissions, a significant mass fraction of NMOCs (up to 80%) remained uncharacterized or unidentified. Models used to simulate the air quality impacts of BB thus have relied on very limited chemical characterization of the emitted compounds. During the Fourth Fire Lab at Missoula Experiment (FLAME-IV), an unprecedented fraction of emitted NMOCs were identified and quantified through the application of advanced analytical techniques. Here we use FLAME-IV data to improve BB emissions speciation profiles for individual fuel types. From box model simulations we evaluate the sensitivity of predicted precursor and pollutant concentrations (e.g., formaldehyde, acetaldehyde, and terpene oxidation products) to differences in the emission speciation profiles, for a range of ambient conditions (e.g., high vs. low NOx). Appropriate representation of emitted NMOCs in models is critical for the accurate prediction of downwind air quality. Explicit simulation of hundreds of NMOCs is not feasible; therefore we also investigate the consequences of using existing assumptions and lumping schemes to map individual NMOCs to model surrogates and we consider alternative strategies. The updated BB emissions speciation profiles lead to markedly different surrogate compound distributions than the default speciation profiles, and box model results suggest that these differences are likely to affect predictions of PM and important gas-phase species in chemical transport models. This study highlights the potential for further BB emissions characterization studies, with concerted model development efforts, to improve the accuracy of BB predictions using necessarily simplified mechanisms.

  9. Air-stable spin-coated naphthalocyanine transistors for enhanced chemical vapor detection.

    PubMed

    Royer, James E; Zhang, Chengyi; Kummel, Andrew C; Trogler, William C

    2012-04-10

    Air-stable organic thin-film transistor (OTFT) sensors fabricated using spin-cast films of 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (OBNc) demonstrated improved chemical vapor sensitivity and selectivity relative to vacuum-deposited phthalocyanine (H(2)Pc) OTFTs. UV-vis spectroscopy data show that annealed spin-cast OBNc films exhibit a red-shift in the OBNc Q-band λ(max) which is generally diagnostic of improved π-orbital overlap in phthalocyanine ring systems. Annealed OBNc OTFTs have mobilities of 0.06 cm(2) V(-1) s(-1), low threshold voltages (|V(th)| < 1 V), and on/off ratios greater than 10(6). These air-stable device parameters are utilized for sensing modalities which enhance the sensitivity and selectivity of OBNc OTFTs relative to H(2)Pc OTFTs. While both sensors exhibit mobility decreases for all analytes, only OBNc OTFTs exhibit V(th) changes for highly polar/nonpolar analytes. The observed mobility decreases for both sensors are consistent with electron donation trends via hydrogen bonding by basic analytes. In contrast, V(th) changes for OBNc sensors appear to correlate with the analyte's octanol-water partition coefficient, consistent with polar molecules stabilizing charge in the organic semiconductor film. The analyte induced V(th) changes for OBNc OTFTs can be employed to develop selective multiparameter sensors which can sense analyte stabilized fixed charge in the film. PMID:22376236

  10. Bioassay-directed chemical analysis and detection of mutagenicity in ambient air of the coke oven.

    PubMed

    Dobiás, L; Kůsová, J; Gajdos, O; Vidová, P; Gajdosová, D; Havránková, J; Fried, M; Binková, B; Topinka, J

    1999-09-30

    In the present study, we summarize the results of studies on the mutagenic potential of the main fractions and subfractions of extractable organic material (EOM) in the ambient air at the workplaces of the coke oven. The objective of our experiments was to apply the Bioassay-Directed Chemical Analysis (with the use of the Ames test) for the identification of the differences in the mutagenicity of these fractions, in relationship to the complex mixture of EOM in occupational air. From the evaluation of results, it is possible to deduce the following conclusions: (1) The comparison of the mutagenicity in the main fractions (basic, acidic, neutral) demonstrates the existence of differences in mutagenic potential. Of the total mutagenicity, 20.4% is in the basic fraction, 25.4% in the acidic fraction and 54.2% in the neutral fraction. (2) In general, 90.1% of the mutagenicity found in the basic, acidic and neutral fractions together was associated with the requirement of metabolic activation in vitro (+S9). In the case of the neutral fraction, it was 51.8%. (3) These results also suggest that frameshift mutations are the major component (53.8%) of the total mutagenicity of the main fractions. (4) With regards to the mutagenicity of organic compounds in the neutral fraction it appeared that genotoxicants of its subfractions (slightly and moderately polar and aromatic) play the main role. Carcinogenic aromatic hydrocarbons (PAH) and genotoxic nitrocompounds play an important role as determinants of the mutagenic potential of complex mixtures of harmful compounds in ambient air. This is confirmed first by the results of short-term bacterial tests. PMID:10575437

  11. Optimization of air monitoring networks using chemical transport model and search algorithm

    NASA Astrophysics Data System (ADS)

    Araki, Shin; Iwahashi, Koki; Shimadera, Hikari; Yamamoto, Kouhei; Kondo, Akira

    2015-12-01

    Air monitoring network design is a critical issue because monitoring stations should be allocated properly so that they adequately represent the concentrations in the domain of interest. Although the optimization methods using observations from existing monitoring networks are often applied to a network with a considerable number of stations, they are difficult to be applied to a sparse network or a network under development: there are too few observations to define an optimization criterion and the high number of potential monitor location combinations cannot be tested exhaustively. This paper develops a hybrid of genetic algorithm and simulated annealing to combine their power to search a big space and to find local optima. The hybrid algorithm as well as the two single algorithms are applied to optimize an air monitoring network of PM2.5, NO2 and O3 respectively, by minimization of the mean kriging variance derived from simulated values of a chemical transport model instead of observations. The hybrid algorithm performs best among the algorithms: kriging variance is on average about 4% better than for GA and variability between trials is less than 30% compared to SA. The optimized networks for the three pollutants are similar and maps interpolated from the simulated values at these locations are close to the original simulations (RMSE below 9% relative to the range of the field). This also holds for hourly and daily values although the networks are optimized for annual values. It is demonstrated that the method using the hybrid algorithm and the model simulated values for the calculation of the mean kriging variance is of benefit to the optimization of air monitoring networks.

  12. [Separation and purification of Al13 by chemical precipitation and metathesis].

    PubMed

    Li, Guo-Hong; Shi, Bao-You; Wang, Dong-Sheng; Cui, Ya-Li

    2007-02-01

    PACls with different concentrations were prepared by adding sodium carbonate powder into AlCl13 solution. Medium concentration and high Al13 content of PACl was chosen to carry out Al13 separation processes. The influences of SO4/Al molar ratio and the initial total Al concentration on the precipitation reactions of sulfate with different Al species were investigated. The factors influencing the metathesis reaction between solid Al13-SO4 and Ba(NO3)2 were evaluated. Results showed that high Al13 PACl could be obtained at the medium high concentration range of 0.4 - 0.6 mol/L, the optimum SO4/Al ratio was 0.6:1 for precipitation- separation of Al13, Al13 -SO4 precipitates were mostly consisted of tetrahedral crystals. During the metathesis reaction, Ba/SO4 molar ratio of 1:1 is the optimal value. Small range temperature variation and ultrasonic action had no marked influence on metathesis reaction rate and final Al13 concentration. Higher initial Ba(NO3)2 concentration could produce higher concentration Al13 accordingly. The purity of Al13 solution could be reached to 92.1% statistically. PMID:17489196

  13. Development program for magnetically assisted chemical separation: Evaluation of cesium removal from Hanford tank supernatant

    SciTech Connect

    Nunez, L.; Buchholz, B.A.; Ziemer, M.; Dyrkacz, G.; Kaminski, M.; Vandegrift, G.F.; Atkins, K.J.; Bos, F.M.; Elder, G.R.; Swift, C.A.

    1994-12-01

    Magnetic particles (MAG*SEP{sup SM}) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP{sup SM} particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP{sup SM} particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP{sup SM} particles with a gamma dose equivalent to 100 cycles of use. This irradiation decreased the loading capacity and distribution ratios for the particles by greater than 75%. The particles demonstrated high sensitivity to radiolytic damage due to the degradation of the polymeric regions. These results were supported by optical microscopy measurements. Overall, use of magnetic particles for cesium separation under nuclear waste conditions was found to be marginally effective.

  14. A new sampler for collecting separate dry and wet atmospheric depositions of trace organic chemicals

    NASA Astrophysics Data System (ADS)

    Waite, Don T.; Cessna, Allan J.; Gurprasad, Narine P.; Banner, James

    Studies conducted in Saskatchewan and elsewhere have demonstrated the atmospheric transport of agricultural pesticides and other organic contaminants and their deposition into aquatic ecosystems. To date these studies have focused on ambient concentrations in the atmosphere and in wet precipitation. To measure the dry deposition of organic chemicals, a new sampler was designed which uses a moving sheet of water to passively trap dry particles and gasses. The moving sheet of water drains into a reservoir and, during recirculation through the sampler, is passed through an XAD-2 resin column which adsorbs the trapped organic contaminants. All surfaces which contact the process water are stainless steel or Teflon. Chemicals collected can be related to airborne materials depositing into aquatic ecosystems. The sampler has received a United States patent (number 5,413,003 - 9 May 1996) with the Canadian patent pending. XAD-2 resin adsorption efficiencies for 10 or 50 μg fortifications of ten pesticides ranged from 76% for atrazine (2-chloro-4-ethylamino-6-isopropylamino- S-triazine) to 110% for triallate [ S-(2,3,3-trichloro-2-phenyl)bis(1-methylethyl)carbamothioate], dicamba (2-methoxy-3,6-dichlorobenzoic acid) and toxaphene (chlorinated camphene mixture). Field testing using duplicate samplers showed good reproducibility and amounts trapped were consistent with those from high volume and bulk pan samplers located on the same site. Average atmospheric dry deposition rates of three chemicals, collected for 5 weeks in May and June, were: dicamba, 69 ng m -2 da -1; 2,4-D (2,4-dichlorophenoxyacetic acid), 276 ng m -2 da -1: and, γ-HCH ( γ-1, 2, 3, 4, 5, 6-hexachlorocyclohexane), 327 ng m -2 da -1.

  15. Impact of in-barn manure separation on biological air quality in an experimental setup identical to that in swine buildings.

    PubMed

    Lavoie, J; Godbout, S; Lemay, S P; Belzile, M

    2009-07-01

    In-barn manure separation systems are becoming popular due to various environmental pressures on the swine industry. According to the literature, separation of feces and urine directly underneath the slats should have a positive impact on barn air quality. Removal and rapid separation of the two phases (solid/liquid) would reduce the dust and bioaerosol emissions, which would significantly improve the air quality in pig-housing facilities. From an occupational health and safety perspective, the maximum endotoxin and total bacteria concentrations to ensure workers' safety should not exceed 450 endotoxin units per cubic meter of air (EU m(-3)) and 10(4) colony-forming units per cubic meter of air (CFU m(-3)), respectively. In the current study, the effect on air quality of six in-barn manure handling systems was measured. A flat scraper system and four separation systems installed under the slats (a conveyor belt system, a conveyor net system, and a V-shaped scraper operated at two operation frequencies) were evaluated and compared to a conventional pull-plug system (control). The experiment took place in twelve independent and identical rooms housing four grower-finisher pigs each, and air samples were collected and analyzed for total dust, endotoxins, bacteria, and mold counts. The results obtained from this experimental setup show that the separation of feces and urine under the slats would concentrate at least 80% of the phosphorus in the solid phase. The total bacteria and endotoxin concentrations are lower than those found in commercial hog barns but remain higher than the recommended levels. Only the total dust concentrations are approximately 10% of their regulated value. This separation has no impact on dust and bioaerosol concentrations compared to the control. PMID:19728546

  16. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  17. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  18. Surface Decontamination of Chemical Agent Surrogates Using an Atmospheric Pressure Air Flow Plasma Jet

    NASA Astrophysics Data System (ADS)

    Li, Zhanguo; Li, Ying; Cao, Peng; Zhao, Hongjie

    2013-07-01

    An atmospheric pressure dielectric barrier discharge (DBD) plasma jet generator using air flow as the feedstock gas was applied to decontaminate the chemical agent surrogates on the surface of aluminum, stainless steel or iron plate painted with alkyd or PVC. The experimental results of material decontamination show that the residual chemical agent on the material is lower than the permissible value of the National Military Standard of China. In order to test the corrosion effect of the plasma jet on different material surfaces in the decontamination process, corrosion tests for the materials of polymethyl methacrylate, neoprene, polyvinyl chloride (PVC), polyethylene (PE), phenolic resin, iron plate painted with alkyd, stainless steel, aluminum, etc. were carried out, and relevant parameters were examined, including etiolation index, chromatism, loss of gloss, corrosion form, etc. The results show that the plasma jet is slightly corrosive for part of the materials, but their performances are not affected. A portable calculator, computer display, mainboard, circuit board of radiogram, and a hygrometer could work normally after being treated by the plasma jet.

  19. Application of SOS umu-test for the detection of genotoxic volatile chemicals and air pollutants

    SciTech Connect

    Ong, T.M.; Stewart, J.; Wen, Y.F.; Whong, W.Z.

    1987-01-01

    The SOS umu-test has been used for the detection of DNA-damaging agents. In this system the plasmid pSK1002 carrying a fused gene umuC-lacZ was introduced into Salmonella typhimurium TA1535. The SOS function induced by genotoxic agents is detected by a colorimetric measurement of beta-galactosidase activity encoded by the lacZ gene, which is regulated by the Umu operon. This system was used with modifications to study the SOS function inducibility of volatile chemicals (propylene oxide, methyl bromide, and ethylene dibromide) and air pollutants (diesel emission, welding fumes, and cigarette smoke). Tester cells were exposed directly to the test material. The enzyme activity of the treated cells was measured according to the established procedure. Results of the study showed that all chemicals and pollutants tested induced SOS function in a dose-related manner. These results indicate that the SOS umu-test is potentially useful for the in situ detection of genotoxic agents in occupational settings.

  20. Chemical kinetic analysis of hydrogen-air ignition and reaction times

    NASA Technical Reports Server (NTRS)

    Rogers, R. C.; Schexnayder, C. J., Jr.

    1981-01-01

    An anaytical study of hydrogen air kinetics was performed. Calculations were made over a range of pressure from 0.2 to 4.0 atm, temperatures from 850 to 2000 K, and mixture equivalence ratios from 0.2 to 2.0. The finite rate chemistry model included 60 reactions in 20 species of the H2-O2-N2 system. The calculations also included an assessment of how small amounts of the chemicals H2O, NOx, H2O2, and O3 in the initial mixture affect ignition and reaction times, and how the variation of the third body efficiency of H2O relative of N2 in certain key reactions may affect reaction time. The results indicate that for mixture equivalence ratios between 0.5 and 1.7, ignition times are nearly constant; however, the presence of H2O and NO can have significant effects on ignition times, depending on the mixture temperature. Reaction time is dominantly influenced by pressure but is nearly independent of initial temperature, equivalence ratio, and the addition of chemicals. Effects of kinetics on reaction at supersonic combustor conditions are discussed.

  1. Analysis of turbulent free-jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.; Glass, I. I.; Evans, J. S.

    1979-01-01

    A numerical analysis is presented of the nonequilibrium flow field resulting from the turbulent mixing and combustion of an axisymmetric hydrogen jet in a supersonic parallel ambient air stream. The effective turbulent transport properties are determined by means of a two-equation model of turbulence. The finite-rate chemistry model considers eight elementary reactions among six chemical species: H, O, H2O, OH, O2 and H2. The governing set of nonlinear partial differential equations was solved by using an implicit finite-difference procedure. Radial distributions were obtained at two downstream locations for some important variables affecting the flow development, such as the turbulent kinetic energy and its dissipation rate. The results show that these variables attain their peak values on the axis of symmetry. The computed distribution of velocity, temperature, and mass fractions of the chemical species gives a complete description of the flow field. The numerical predictions were compared with two sets of experimental data. Good qualitative agreement was obtained.

  2. Interdisciplinary approach to assessing the health risk of air toxic chemicals: An overview

    SciTech Connect

    Grose, E.C.; Selgrade, M.J.K.; Busnell, P.J.; Simmons, J.E.; Allen, J.

    1990-01-01

    To assist the regulatory branch of the Environmental Protection Agency in addressing the risk assessment of air toxics, the Health Effects Research Laboratory initiated a comprehensive inhalation toxicology program to provide key health effects data missing from the current data base. A priority ranking of chemicals based on the potential for substantial human exposure and the need for health effects data was developed to identify candidate chemicals for toxicological research. The major goal of the program is to evaluate the concentration-response from acute, intermittent and subchronic inhalation exposures to developmental, genetic, hepatic, immunologic, neurologic, pulmonary and reproductive toxicity. Although the main emphasis is on inhalation as the primary route of exposure, some of the laboratories will compare inhalation to other routes, such as oral, to better understand the influence of route of exposure and hence the potential applicability of existing health data. Acute and intermittent exposures will be done for all compounds. Upon evaluation of the acute results, a decision will be made as to whether subchronic studies are needed. Endpoints that show unusual sensitivity may be investigated in greater detail. The total length of exposure will vary from 1 to 21 days. The daily length of exposure will range from 1 to 8 hr. If adverse effects are observed at ambient levels, the time to recovery after exposure will be investigated.

  3. Surface-chemistry-sensitive spectral features of In-Ga-Zn-O thin film: Cleaned, air-passivated, and sputter-phase-separated surfaces

    NASA Astrophysics Data System (ADS)

    Kang, Se Jun; Baik, Jae Yoon; Thakur, Anup; Kim, Hyeong-Do; Shin, Hyun-Joon; Chung, JaeGwan; Lee, Jaecheol; Lee, JaeHak

    2011-07-01

    The photoelectron spectral features and corresponding energy band diagrams of amorphous indium gallium zinc oxide ( a-IGZO) thin films were investigated for different surface chemistries. Cleaned-IGZO surface had a deep subgap state (DSS), the binding energy (BE) of which expanded to ˜1.5 eV. When stored in air, IGZO surface became contaminant passivated and DSS became negligible. Sputtering resulted in phase separation of surface into metallic In and lesser In and Zn containing IGZO. Compared with IGZO, the air-passivated surface and phase-separated surface, respectively, had a more weakly conducting environment and a higher BE spectral shift.

  4. Chemical and isotopic fractionation by grain size separates. [in interstellar medium

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1980-01-01

    Fractionation of refractory elements according to grain size is argued to occur during their growth. Two major modes should exist: (1) during thermal condensation sequences whenever the condensing phase (e.g. Mg2SiO4) does not alloy with the precondensed phase (e.g. MgAl2O4); (2) during accretion of gaseous atoms in the nonequilibrated interstellar medium. Processes dynamically sorting grains according to size (e.g. sedimentation) therefore are potentially capable of achieving fractionations normally attributed to separations of dust and gas. This paper considers the first mode during supernova condensation; however, it also can occur in an equilibrium solar condensation sequence owing to an overlooked freedom in that simplified description.

  5. Real-Time Volumetric Phase Monitoring: Advancing Chemical Analysis by Countercurrent Separation.

    PubMed

    Pauli, Guido F; Pro, Samuel M; Chadwick, Lucas R; Burdick, Thomas; Pro, Luke; Friedl, Warren; Novak, Nick; Maltby, John; Qiu, Feng; Friesen, J Brent

    2015-07-21

    Countercurrent separation (CCS) utilizes the differential partitioning behavior of analytes between two immiscible liquid phases. We introduce the first platform ("CherryOne") capable of real-time monitoring, metering, and control of the dynamic liquid-liquid CCS process. Automated phase monitoring and volumetrics are made possible with an array of sensors, including the new permittivity-based phase metering apparatus (PMA). Volumetric data for each liquid phase are converted into a dynamic real-time display of stationary phase retention (Sf) and eluent partition coefficients (K), which represent critical parameters of CCS reproducibility. When coupled with the elution-extrusion operational mode (EECCC), automated Sf and K determination empowers untargeted and targeted applications ranging from metabolomic analysis to preparative purifications. PMID:26152934

  6. Quantifying components of the hydrologic cycle in Virginia using chemical hydrograph separation and multiple regression analysis

    USGS Publications Warehouse

    Sanford, Ward E.; Nelms, David L.; Pope, Jason P.; Selnick, David L.

    2012-01-01

    This study by the U.S. Geological Survey, prepared in cooperation with the Virginia Department of Environmental Quality, quantifies the components of the hydrologic cycle across the Commonwealth of Virginia. Long-term, mean fluxes were calculated for precipitation, surface runoff, infiltration, total evapotranspiration (ET), riparian ET, recharge, base flow (or groundwater discharge) and net total outflow. Fluxes of these components were first estimated on a number of real-time-gaged watersheds across Virginia. Specific conductance was used to distinguish and separate surface runoff from base flow. Specific-conductance data were collected every 15 minutes at 75 real-time gages for approximately 18 months between March 2007 and August 2008. Precipitation was estimated for 1971–2000 using PRISM climate data. Precipitation and temperature from the PRISM data were used to develop a regression-based relation to estimate total ET. The proportion of watershed precipitation that becomes surface runoff was related to physiographic province and rock type in a runoff regression equation. Component flux estimates from the watersheds were transferred to flux estimates for counties and independent cities using the ET and runoff regression equations. Only 48 of the 75 watersheds yielded sufficient data, and data from these 48 were used in the final runoff regression equation. The base-flow proportion for the 48 watersheds averaged 72 percent using specific conductance, a value that was substantially higher than the 61 percent average calculated using a graphical-separation technique (the USGS program PART). Final results for the study are presented as component flux estimates for all counties and independent cities in Virginia.

  7. Solid reaction products and aluminate solutions that form during the operation of an air-aluminum chemical power supply

    NASA Astrophysics Data System (ADS)

    Okorokova, N. S.; Sevruk, S. D.; Suvorova, E. V.; Farmakovskaya, A. A.

    2015-12-01

    A solution to the set of problems concerning the solid reaction products and the aluminate solutions that form during the operation of an aluminum-closed power supply system for self-contained objects is proposed. The system is based on a resource-saving technology using an aluminum energy carrier in an air-aluminum chemical power supply and related energy installations. The boundaries of the metastable and labile state regions of aluminate solutions and the real degrees of supersaturation that can be attained when aluminum is dissolved in an electrolyte during the operation of an air-aluminum chemical power supply are determined.

  8. Association of allergic asthma emergency room visits with the main biological and chemical air pollutants.

    PubMed

    Makra, László; Matyasovszky, István; Bálint, Beatrix

    2012-08-15

    Joint effect of biological (pollen) and chemical air pollutants on asthma emergency room (ER) visits was analyzed for Szeged region of Southern Hungary. Our database of a nine-year period (1999-2007) includes daily number of asthma emergency room (ER) visits, and daily mean concentrations of CO, PM(10), NO, NO(2), O(3) and SO(2), furthermore two pollen variables (Ambrosia and total pollen excluding Ambrosia), as well. The analysis was performed for ER visits of asthma bronchiale using two age groups (adults and the elderly) of males and females for three seasons. Factor analysis was performed in order to clarify the relative importance of the pollutant variables affecting asthma ER visits. Asthma ER visits denote notably stronger associations with the pollutants in adult male than in adult female patients both for the pollen season of Ambrosia and the pollen-free season. Furthermore, adults are substantially more sensitive to severe asthma attack than the elderly for the season of total pollen excluding Ambrosia pollen. The joint effect of the chemical and pollen variables is the highest for the asthma ER cases in the pollen season of Ambrosia, basically due to the extra impact of the total pollen excluding Ambrosia pollen and partly due to Ambrosia pollen. A nonparametric regression technique was applied to discriminate between events of ER visit-no ER visit using pollen and chemical pollutants as explaining variables. Based on multiple correlations, the strongest relationships between ER visits and pollutants are observed during the pollen-free season. The elderly group with asthma bronchiale is characterized by weaker relationships between ER visits and pollutants compared to adults. Ratio of the number of correct decisions on the events of ER visit-no ER visit is lowest for the season of total pollen excluding Ambrosia pollen. Otherwise, similar conclusions hold as those received by multiple correlations. PMID:22750174

  9. The production of chemicals from food processing wastes using a novel fermenter separator. Annual progress report, January 1993--March 1994

    SciTech Connect

    Dale, M.C.; Venkatesh, K.V.; Choi, H.; Salicetti-Piazza, L.; Borgos-Rubio, N.; Okos, M.R.; Wankat, P.C.

    1994-03-15

    The basic objective of this project is to convert waste streams from the food processing industry to usable fuels and chemicals using novel bioreactors. These bioreactors should allow economical utilization of waste (whey, waste sugars, waste starch, bottling wastes, candy wastes, molasses, and cellulosic wastes) by the production of ethanol, acetone/butanol, organic acids (acetic, lactic, and gluconic), yeast diacetyl flavor, and antifungal compounds. Continuous processes incorporating various processing improvements such as simultaneous product separation and immobilized cells are being developed to allow commercial scale utilization of waste stream. The production of ethanol by a continuous reactor-separator is the process closest to commercialization with a 7,500 liter pilot plant presently sited at an Iowa site to convert whey lactose to ethanol. Accomplishments during 1993 include installation and start-up of a 7,500 liter ICRS for ethanol production at an industry site in Iowa; Donation and installation of a 200 liter yeast pilot Plant to the project from Kenyon Enterprises; Modeling and testing of a low energy system for recovery of ethanol from vapor is using a solvent absorption/extractive distillation system; Simultaneous saccharification/fermentation of raw corn grits and starch in a stirred reactor/separator; Testing of the ability of `koji` process to ferment raw corn grits in a `no-cook` process.

  10. Reprint of: A numerical modelling of gas exchange mechanisms between air and turbulent water with an aquarium chemical reaction

    NASA Astrophysics Data System (ADS)

    Nagaosa, Ryuichi S.

    2014-08-01

    This paper proposes a new numerical modelling to examine environmental chemodynamics of a gaseous material exchanged between the air and turbulent water phases across a gas-liquid interface, followed by an aquarium chemical reaction. This study uses an extended concept of a two-compartment model, and assumes two physicochemical substeps to approximate the gas exchange processes. The first substep is the gas-liquid equilibrium between the air and water phases, A(g)⇌A(aq), with Henry's law constant H. The second is a first-order irreversible chemical reaction in turbulent water, A(aq)+H2O→B(aq)+H+ with a chemical reaction rate κA. A direct numerical simulation (DNS) technique has been employed to obtain details of the gas exchange mechanisms and the chemical reaction in the water compartment, while zero velocity and uniform concentration of A is considered in the air compartment. The study uses the different Schmidt numbers between 1 and 8, and six nondimensional chemical reaction rates between 10(≈0) to 101 at a fixed Reynolds number. It focuses on the effects of the Schmidt number and the chemical reaction rate on fundamental mechanisms of the gas exchange processes across the interface.

  11. A numerical modelling of gas exchange mechanisms between air and turbulent water with an aquarium chemical reaction

    NASA Astrophysics Data System (ADS)

    Nagaosa, Ryuichi S.

    2014-01-01

    This paper proposes a new numerical modelling to examine environmental chemodynamics of a gaseous material exchanged between the air and turbulent water phases across a gas-liquid interface, followed by an aquarium chemical reaction. This study uses an extended concept of a two-compartment model, and assumes two physicochemical substeps to approximate the gas exchange processes. The first substep is the gas-liquid equilibrium between the air and water phases, A(g)⇌A(aq), with Henry's law constant H. The second is a first-order irreversible chemical reaction in turbulent water, A(aq)+H2O→B(aq)+H+ with a chemical reaction rate κA. A direct numerical simulation (DNS) technique has been employed to obtain details of the gas exchange mechanisms and the chemical reaction in the water compartment, while zero velocity and uniform concentration of A is considered in the air compartment. The study uses the different Schmidt numbers between 1 and 8, and six nondimensional chemical reaction rates between 10(≈0) to 101 at a fixed Reynolds number. It focuses on the effects of the Schmidt number and the chemical reaction rate on fundamental mechanisms of the gas exchange processes across the interface.

  12. Separation of root respiration from total soil respiration using carbon-13 labelling during free-air carbon dioxide enrichment (FACE)

    SciTech Connect

    Andrews, J.A.; Harrison, K.G.; Matamala, R.; Schlesinger, W.H.

    1999-10-01

    Soil respiration constitutes a major component of the global carbon cycle and is likely to be altered by climate change. However, there is an incomplete understanding of the extent to which various processes contribute to total soil respiration, especially the contributions of root and rhizosphere respiration. Here, using a stable carbon isotope tracer, the authors separate the relative contributions of root and soil heterotrophic respiration to total soil respiration in situ. The Free-Air Carbon dioxide Enrichment (FACE) facility in the Duke University Forest (NC) fumigates plots of an undisturbed loblolly pine (Pinus taeda L.) forest with CO{sub 2} that is strongly depleted in {sup 13}C. This labeled CO{sub 2} is found in the soil pore space through live root and mycorrhizal respiration and soil heterotroph respiration of labile root exudates. By measuring the depletion of {sup 13}CO{sub 2} in the soil system, the authors found that the rhizosphere contribution to soil CO{sub 2} reflected the distribution of fine roots in the soil and that late in the growing season roots contributed 55% of total soil respiration at the surface. This estimate may represent an upper limit on the contribution of roots to soil respiration because high atmospheric CO{sub 2} often increases in root density and/or root activity in the soil.

  13. Controlling charge separation and recombination by chemical design in donor-acceptor dyads.

    PubMed

    Liu, Li; Eisenbrandt, Pierre; Roland, Thomas; Polkehn, Matthias; Schwartz, Pierre-Olivier; Bruchlos, Kirsten; Omiecienski, Beatrice; Ludwigs, Sabine; Leclerc, Nicolas; Zaborova, Elena; Léonard, Jérémie; Méry, Stéphane; Burghardt, Irene; Haacke, Stefan

    2016-07-21

    Conjugated donor-acceptor block co-oligomers that self-organize into D-A mesomorphic arrays have raised increasing interest due to their potential applications in organic solar cells. We report here a combined experimental and computational study of charge transfer (CT) state formation and recombination in isolated donor-spacer-acceptor oligomers based on bisthiophene-fluorene (D) and perylene diimide (A), which have recently shown to self-organize to give a mesomorphic lamellar structure at room temperature. Using femtosecond transient absorption spectroscopy and Time-Dependent Density Functional Theory in combination with the Marcus-Jortner formalism, the observed increase of the CT lifetimes is rationalized in terms of a reduced electronic coupling between D and A brought about by the chemical design of the donor moiety. A marked dependence of the CT lifetime on solvent polarity is observed, underscoring the importance of electrostatic effects and those of the environment at large. The present investigation therefore calls for a more comprehensive design approach including the effects of molecular packing. PMID:27341086

  14. The production of fuels and chemicals from food processing wastes using a novel fermenter separator

    SciTech Connect

    Dale, M.C.; Venkatesh, K.V.; Choi, Hojoon; Moelhman, M.; Saliceti, L.; Okos, M.R.; Wankat, P.C.

    1991-12-01

    During 1991, considerable progress was made on the waste utilization project. Two small Wisconsin companies have expressed an interest in promoting and developing the ICRS technology. Pilot plant sites at (1) Hopkinton, IA, for a sweet whey plant, and Beaver Dam WI, for an acid whey site have been under development siting ICRS operations. The Hopkinton, IA site is owned and operated by Permeate Refining Inc., who have built a batch ethanol plant across the street from Swiss Valley Farms cheddar cheese operations. Permeate from Swiss Valley is piped across to PRI. PRI has signed a contract to site a 300--500,000 gallon/yr to ICRS pilot plant. They feel that the lower labor, lower energy, continuous process offered by the ICRS will substantially improve their profitability. Catalytics, Inc, is involved with converting whey from a Kraft cream cheese operation to ethanol and yeast. A complete project including whey concentration, sterilization, and yeast growth has been designed for this site. Process design improvements with the ICRS focussed on ethanol recovery techniques during this year's project. A solvent absorption/extractive distillation (SAED) process has been developed which offers the capability of obtaining an anhydrous ethanol product from vapors off 3 to 9% ethanol solutions using very little energy for distillation. Work on products from waste streams was also performed. a. Diacetyl as a high value flavor compound was very successfully produced in a Stirred Tank Reactor w/Separation. b. Yeast production from secondary carbohydrates in the whey, lactic acid, and glycerol was studied. c. Lactic acid production from cellulose and lactose studies continued. d. Production of anti-fungal reagents by immobilized plant cells; Gossypol has antifungal properties and is produced by G. arboretum.

  15. The Gaia-ESO Survey: Separating disk chemical substructures with cluster models. Evidence of a separate evolution in the metal-poor thin disk

    NASA Astrophysics Data System (ADS)

    Rojas-Arriagada, A.; Recio-Blanco, A.; de Laverny, P.; Schultheis, M.; Guiglion, G.; Mikolaitis, Š.; Kordopatis, G.; Hill, V.; Gilmore, G.; Randich, S.; Alfaro, E. J.; Bensby, T.; Koposov, S. E.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Jofré, P.; Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S.; Chiappini, C.

    2016-02-01

    Context. Recent spectroscopic surveys have begun to explore the Galactic disk system on the basis of large data samples, with spatial distributions sampling regions well outside the solar neighborhood. In this way, they provide valuable information for testing spatial and temporal variations of disk structure kinematics and chemical evolution. Aims: The main purposes of this study are to demonstrate the usefulness of a rigorous mathematical approach to separate substructures of a stellar sample in the abundance-metallicity plane, and provide new evidence with which to characterize the nature of the metal-poor end of the thin disk sequence. Methods: We used a Gaussian mixture model algorithm to separate in the [Mg/Fe] vs. [Fe/H] plane a clean disk star subsample (essentially at RGC< 10 kpc) from the Gaia-ESO survey (GES) internal data release 2 (iDR2). We aim at decomposing it into data groups highlighting number density and/or slope variations in the abundance-metallicity plane. An independent sample of disk red clump stars from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) was used to cross-check the identified features. Results: We find that the sample is separated into five groups associated with major Galactic components; the metal-rich end of the halo, the thick disk, and three subgroups for the thin disk sequence. This is confirmed with the sample of red clump stars from APOGEE. The three thin disk groups served to explore this sequence in more detail. The two metal-intermediate and metal-rich groups of the thin disk decomposition ([Fe/H] > -0.25 dex) highlight a change in the slope at solar metallicity. This holds true at different radial regions of the Milky Way. The distribution of Galactocentric radial distances of the metal-poor part of the thin disk ([Fe/H] < -0.25 dex) is shifted to larger distances than those of the more metal-rich parts. Moreover, the metal-poor part of the thin disk presents indications of a scale height

  16. Environmental assessment, aircraft chemical warfare survivability test program, Naval Air Warfare Center, Aircraft Division, Patuxent River, Maryland

    SciTech Connect

    1992-02-01

    The proposed project, the Aircraft Chemical Warfare Survivability Test Program at Patuxent River Naval Air Station, involves the testing and development of aircraft systems and operating procedures for use in an environment contaminated with chemical/biological warfare agents. The tests will be performed in accordance with a directive from the chief of Naval Operations to obtain and maintain the capability to operate in a chemically-contaminated environment. These tests will be performed under outdoor, warm-weather conditions on a dredge disposal area and adjacent runways to simulate the conditions under which a real-life threat would be encountered.

  17. Influence Of Adsorbent Materials On Streamers Propagation In Air And Induced Chemical Efficiency

    NASA Astrophysics Data System (ADS)

    Guaitella, O.; Marinov, I.; Dong, B.; Rousseau, A.

    2010-07-01

    materials, give a new insight on the main role played by the dielectric in the development and the chemical efficiency of streamers ignited in DBD for air treatment.

  18. Adsorptive separation of rhodium(III) using Fe(III)-templated oxine type of chemically modified chitosan

    SciTech Connect

    Alam, M.S.; Inoue, Katsutoshi; Yoshizuka, Kazuharu; Ishibashi, Hideaki

    1998-03-01

    The oxine type of chemically modified chitosan was prepared by the template crosslinking method using Fe(III) as a template ion. Batchwise adsorption of rhodium(III) on this chemically modified chitosan was examined from chloride media in the absence and presence of a large amount of tin(II). It was observed that the Fe(III)-templated oxine type of chemically modified chitosan shows better performance for rhodium adsorption than that of the original chitosan. When Sn(II) is absent from the solution, Rh(III) is hardly adsorbed on the modified chitosan and the order of selectivity of the adsorption of Rh(III), Pt(IV), and Cu(II) was found to be Pt(IV) > Cu(II) {approx} Rh(III). On the other hand, adsorption of rhodium is significantly increased in the presence of Sn(II) and the selectivity order of the adsorption was drastically changed to Rh(III) > Pt(IV) {much_gt} Cu(II), which ensures selective separation of Rh(III) from their mixture. Adsorption of Rh(III) increases with an increase in the concentration of Sn(II) in the aqueous solution, and maximum adsorption is achieved at a molar ratio, [Sn]/[Rh], of >6. The adsorption of Rh(III) decreases at a high concentration of hydrochloric acid. The maximum adsorption capacity was evaluated to be 0.92 mol/kg-dry adsorbent. Stripping tests of rhodium from the loaded chemically modified chitosan were carried out using different kinds of stripping agents containing some oxidizing agent. The maximum stripping of rhodium under these experimental conditions was found to be 72.5% by a single contact with 0.5 M HCl + 8 M HNO{sub 3}.

  19. Chemical constituents of fine particulate air pollution and pulmonary function in healthy adults: the Healthy Volunteer Natural Relocation study.

    PubMed

    Wu, Shaowei; Deng, Furong; Hao, Yu; Shima, Masayuki; Wang, Xin; Zheng, Chanjuan; Wei, Hongying; Lv, Haibo; Lu, Xiuling; Huang, Jing; Qin, Yu; Guo, Xinbiao

    2013-09-15

    The study examined the associations of 32 chemical constituents of particulate matter with an aerodynamic diameter ≤2.5 μm (PM₂.₅) with pulmonary function in a panel of 21 college students. Study subjects relocated from a suburban area to an urban area with changing ambient air pollution levels and contents in Beijing, China, and provided daily morning/evening peak expiratory flow (PEF) and forced expiratory volume in 1s (FEV₂₁) measurements over 6 months in three study periods. There were significant reductions in evening PEF and morning/evening FEV₂₁ associated with various air pollutants and PM₂.₅ constituents. Four PM₂.₅ constituents (copper, cadmium, arsenic and stannum) were found to be most consistently associated with the reductions in these pulmonary function measures. These findings provide clues for the respiratory effects of specific particulate chemical constituents in the context of urban air pollution. PMID:23747477

  20. Air-sea Exchange of Dimethylsulfide (DMS) - Separation of the Transfer Velocity to Buoyancy, Turbulence, and Wave Driven Components

    NASA Astrophysics Data System (ADS)

    Yang, M.; Blomquist, B.; Huebert, B. J.; Fairall, C. W.

    2009-12-01

    In the past several years, we have measured the sea-to-air flux of DMS directly with eddy covariance on five cruises in distinct oceanic environments, including the equatorial Pacific (TAO 2003), Sargasso Sea (Biocomplexity 2004), Northern Atlantic (DOGEE 2007), Southern Ocean (SO-GasEX 2008), and Peruvian/Chilean upwelling region (VOCALS-REx 2008). Normalizing DMS flux by its concurrent air-sea concentration difference gave us the transfer velocity of DMS (kDMS). Our wealth of kDMS measurements (~2000 hourly values) in very different oceans and across a wide range of wind speeds (0.5~20.5 m/s) provides an opportunity to evaluate existing parameterizations of k and quantify the importance of various controlling factors on gas exchange. Gas exchange in different wind speed regimes is driven by distinct physical mechanisms. In low winds (<4 m/s), buoyancy-driven convection results in a finite and positive kDMS. In moderate winds (4~10 m/s), turbulence from wind-stress prevails, as we found a near linear dependence of kDMS on wind speed and on friction velocity (u*). In high winds (>10 m/s), there is additional bubble-mediated exchange from wave-breaking, which depends on gas solubility (a function of temperature and to a lesser degree, salinity). When normalizing kDMS to a reference temperature of 20°C, we found the oft-used Schmidt number correction (for diffusivity) to be inadequate because it does not account for the temperature dependence in solubility. To quantify the solubility effect, we subtract the small buoyancy-driven term computed by the NOAA-COARE model 3.0a from k660 (kDMS corrected to a Schmidt number of 660). A linear fit to the residual k660 in the moderate wind regime allows us to further separate the turbulence-driven and wave-breaking components. A solubility correction is applied to the latter, which is then added back to the buoyancy and turbulence-driven terms to give k660,C. Compared to k660, k660,C shows a significant reduction in scatter

  1. Chemical-Specific Representation of Air-Soil Exchange and Soil Penetration in Regional Multimedia Models

    SciTech Connect

    McKone, T.E.; Bennett, D.H.

    2002-08-01

    In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil with fixed properties and boundary conditions. Unlike the analytical solution, which requires fixed boundary conditions, the soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, ground water, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo(a)pyrene, MTBE, TCDD, and tritium.

  2. Indoor Chemical Exposures: Humans' Non-respiratory Interactions with Room Air

    SciTech Connect

    Charles Weschler

    2010-03-29

    March 18, 2010 Berkeley Lab Environmental Energy Technology Division distinguished lecture: The marked difference in pollutant concentrations between an occupied and un-occupied room are only partially explained by human bio-effluents. Humans alter levels of ozone and related oxidants such as nitrate and hydroxyl radicals in the rooms they inhabit; in effect, they change the oxidative capacity of room air. Ozone-initiated reactions on exposed skin, hair and clothing generate products, including potentially irritating chemicals whose concentrations are much higher in the occupant's breathing zone than in the core of the room. Charles J. Weschler is a Professor at the School of Public Health, the Department of Environmental and Occupational Medicine and the Environmental and Occupational Health Sciences Institute (EOHSI) at the University of Medicine and Dentistry of New Jersey (UMDNJ)/Robert Wood Johnson Medical School & Rutgers University (New Jersey). He is also a Visiting Professor at the International Centre for Indoor Environment and Energy, Technical University of Denmark (DTU, Lyngby, Denmark).

  3. Indoor Chemical Exposures: Humans' Non-respiratory Interactions with Room Air

    ScienceCinema

    Charles Weschler

    2010-09-01

    March 18, 2010 Berkeley Lab Environmental Energy Technology Division distinguished lecture: The marked difference in pollutant concentrations between an occupied and un-occupied room are only partially explained by human bio-effluents. Humans alter levels of ozone and related oxidants such as nitrate and hydroxyl radicals in the rooms they inhabit; in effect, they change the oxidative capacity of room air. Ozone-initiated reactions on exposed skin, hair and clothing generate products, including potentially irritating chemicals whose concentrations are much higher in the occupant's breathing zone than in the core of the room. Charles J. Weschler is a Professor at the School of Public Health, the Department of Environmental and Occupational Medicine and the Environmental and Occupational Health Sciences Institute (EOHSI) at the University of Medicine and Dentistry of New Jersey (UMDNJ)/Robert Wood Johnson Medical School & Rutgers University (New Jersey). He is also a Visiting Professor at the International Centre for Indoor Environment and Energy, Technical University of Denmark (DTU, Lyngby, Denmark).

  4. Analysis of turbulent free jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.

    1978-01-01

    The nonequilibrium flow field resulting from the turbulent mixing and combustion of a supersonic axisymmetric hydrogen jet in a supersonic parallel coflowing air stream is analyzed. Effective turbulent transport properties are determined using the (K-epsilon) model. The finite-rate chemistry model considers eight reactions between six chemical species, H, O, H2O, OH, O2, and H2. The governing set of nonlinear partial differential equations is solved by an implicit finite-difference procedure. Radial distributions are obtained at two downstream locations of variables such as turbulent kinetic energy, turbulent dissipation rate, turbulent scale length, and viscosity. The results show that these variables attain peak values at the axis of symmetry. Computed distributions of velocity, temperature, and mass fraction are also given. A direct analytical approach to account for the effect of species concentration fluctuations on the mean production rate of species (the phenomenon of unmixedness) is also presented. However, the use of the method does not seem justified in view of the excessive computer time required to solve the resulting system of equations.

  5. Quantum chemical modeling of humic acid/air equilibrium partitioning of organic vapors.

    PubMed

    Niederer, Christian; Goss, Kai-Uwe

    2007-05-15

    Classical approaches for predicting soil organic matter partition coefficients of organic compounds require a calibration with experimental partition data and, for good accuracy, experimental compound descriptors. In this study we evaluate the quantum chemical model COSMO-RS in its COSMOtherm implementation for the prediction of about 200 experimental Leonardite humic acid/air partition coefficients without calibration or experimental compound descriptors, but simply based on molecular structures. For this purpose a Leonardite Humic Acid model monomer limited to 31 carbon atoms was derived from 13C NMR analysis, elemental analysis, and acidic function analysis provided in the literature. Altogether the COSMOtherm calculations showed a good performance and we conclude that it may become a very promising tool for the prediction of sorption in soil organic matter for compounds for which the molecular structure is the only reliable information available. COSMOtherm can be expected to be very robust with respectto new and complex compound structures because its calculations are based on a fundamental assessment of the underlying intermolecular forces. In contrast, other empirical models that are also based on the molecular structure of the sorbate have an application domain that is limited by their calibration data set that is often unknown to the user. PMID:17547191

  6. Gaseous chemical compounds in indoor and outdoor air of 602 houses throughout Japan in winter and summer.

    PubMed

    Uchiyama, Shigehisa; Tomizawa, Takuya; Tokoro, Asumo; Aoki, Manami; Hishiki, Mayu; Yamada, Tomomi; Tanaka, Reiko; Sakamoto, Hironari; Yoshida, Tsutomu; Bekki, Kanae; Inaba, Yohei; Nakagome, Hideki; Kunugita, Naoki

    2015-02-01

    A nationwide survey of indoor air quality in Japan was conducted using four types of diffusive samplers. Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 602 houses throughout Japan in winter and summer. Four kinds of diffusive samplers were used in this study: DSD-BPE/DNPH packed with 2,4-dinitrophenyl hydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; VOC-SD packed with Carboxen 564 particles for volatile organic compounds; DSD-TEA packed with triethanolamine impregnated silica for acid gases; and DSD-NH3 packed with phosphoric acid impregnated silica for basic gases. These samplers are small and lightweight and do not require a power source, hence, it was possible to obtain a large number of air samples via mail from throughout Japan. Almost all compounds in indoor air were present at higher levels in summer than in winter. In particular, formaldehyde, toluene, and ammonia were strongly dependent on temperature, and their levels increased with temperature. The nitrogen dioxide concentration in indoor air particularly increased only during winter and was well correlated with the formic acid concentration (correlation coefficient=0.959). Ozone concentrations in indoor air were extremely low compared with the outdoor concentrations. Ozone flowing from outdoor air may be decomposed quickly by chemical compounds in indoor air; therefore, it is suggested that the indoor/outdoor ratio of ozone represents the ventilation of the indoor environment. PMID:25601740

  7. Unusual Adsorption at the Air-Water Interface of a Zwitterionic Carboxybetaine with a Large Charge Separation.

    PubMed

    Ma, Kun; Li, Pei Xun; Dong, Chu Chuan; Thomas, Robert K; Penfold, Jeffrey

    2016-04-12

    The structures of layers of three different dodecylcarboxybetaine surfactants adsorbed at the air-water interface have been determined by neutron reflection. The zwitterionic compounds differed in the length of the spacer separating the quaternary ammonium and carboxylate groups, which was (CH2)1, (CH2)4, or (CH2)8. The limiting area per molecule was found to be 45, 52, or 84 Å(2), respectively, and compared reasonably with results from surface tension showing that the Gibbs prefactor is 1 in each case. Isotopic labeling was used to distinguish between the position of the alkyl and spacer groups in the layer. The spacer was found to be well-immersed in water for the (CH2)1 and (CH2)4 spacers but significantly above water for the (CH2)8 spacer. The distribution of the (CH2)8 spacer along the surface normal was found to be similar to that of the dodecyl group; i.e., it projects out of the water, contrary to an earlier hypothesis that it forms a loop. Comparison of the overlap of water with dodecyl and spacer groups also indicates that the (CH2)8 spacer is well out of the water. This in turn suggests that the anionic carboxylic acid group, which is dissociated in solution, is not ionized in the adsorbed layer. A further observation is that the dodecylcarboxybetaine with the (CH2)8 spacer reaches surface saturation at one-tenth of the critical micelle concentration. This is highly unusual and is attributed to the long spacer destabilizing the micelle relative to the surface layer. PMID:27010322

  8. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    PubMed Central

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0–20, 20–40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0–20 cm = 1492.4 gC m2 and 20–40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C. PMID:26750143

  9. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    NASA Astrophysics Data System (ADS)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m2 and 20-40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  10. Separation of Scaptotrigona postica workers into defined task groups by the chemical profile on their epicuticle wax layer.

    PubMed

    Poiani, Silvana B; Morgan, E David; Drijfhout, Falko P; da Cruz-Landim, Carminda

    2014-04-01

    During evolution, the cuticle surface of insects acquired functions in communication, such as inter- and intra-specific recognition, identification of gender, physiological state, and fertility. In eusocial bees, the information in the cuticular surface is important not only to discriminate nestmates from non-nestmates but also to identify an individual's class, life phase or task. A comparative study of the cuticular surface chemical profile of workers of Scaptotrigona postica in different phases of life, i.e., newly emerged workers (NE), brood comb area workers (CA), and forager workers (FO) was undertaken by gas chromatography linked to mass spectrometry. Multivariate statistical analysis was performed to verify how workers are grouped according to their chemical profile and to determine which compounds are responsible for separating them into groups. The cuticle surface of workers contains mainly hydrocarbons and a small amount of oxygenated compounds. Multivariate statistical analysis showed qualitative and quantitative variation in relation to the life phases/tasks performed, and all groups were distinct. The most abundant compound found in NE and CA was n-heptacosane, while in FO, it was (Z)-9-heptacosene. The compounds that differentiate NE from other groups are n-tricosane and n-hexacosane. A (Z)-X-octacosene and n-nonacosane are the chemicals that distinguish CA from NE and FO, while 11- and 13-methylpentacosane, (Z)-X-hexacosene, and (Z)-9-heptacosene characterize FO as distinct from NE and CA. The probable function of alkenes is nestmate recognition, mainly in FO. The results show that the cuticle surfaces of workers are characteristic of the phase of life/task performed by workers, allowing intra-colonial recognition. PMID:24752855

  11. WOOD SMOKE IMPACTED AIR: MUTAGENICITY AND CHEMICAL ANALYSIS OF AMBIENT AIR IN A RESIDENTIAL AREA OF JUNEAU, ALASKA (JOURNAL VERSION)

    EPA Science Inventory

    The study was undertaken to determine the bacterial mutagenicity (Ames test) and chemical characteristics of respirable particulate matter collected in the area. Fine particle concentrations for the sampling period of November 16th to January 7th ranged from 1.19 to 209.8 microgr...

  12. A two-step chemical scheme for kerosene-air premixed flames

    SciTech Connect

    Franzelli, B.; Riber, E.; Sanjose, M.; Poinsot, T.

    2010-07-15

    A reduced two-step scheme (called 2S-KERO-BFER) for kerosene-air premixed flames is presented in the context of Large Eddy Simulation of reacting turbulent flows in industrial applications. The chemical mechanism is composed of two reactions corresponding to the fuel oxidation into CO and H{sub 2}O, and the CO - CO{sub 2} equilibrium. To ensure the validity of the scheme for rich combustion, the pre-exponential constants of the two reactions are tabulated versus the local equivalence ratio. The fuel and oxidizer exponents are chosen to guarantee the correct dependence of laminar flame speed with pressure. Due to a lack of experimental results, the detailed mechanism of Dagaut composed of 209 species and 1673 reactions, and the skeletal mechanism of Luche composed of 91 species and 991 reactions have been used to validate the reduced scheme. Computations of one-dimensional laminar flames have been performed with the 2S{sub K}ERO{sub B}FER scheme using the CANTERA and COSILAB softwares for a wide range of pressure ([1; 12] atm), fresh gas temperature ([300; 700] K), and equivalence ratio ([0.6; 2.0]). Results show that the flame speed is correctly predicted for the whole range of parameters, showing a maximum for stoichiometric flames, a decrease for rich combustion and a satisfactory pressure dependence. The burnt gas temperature and the dilution by Exhaust Gas Recirculation are also well reproduced. Moreover, the results for ignition delay time are in good agreement with the experiments. (author)

  13. Hydrologic and chemical data from selected wells and springs in southern Elmore County, including Mountain Home Air Force Base, southwestern Idaho, Fall 1989

    SciTech Connect

    Parliman, D.J.; Young, H.W.

    1990-01-01

    Hydrologic and chemical data were collected during September through November 1989 from 90 wells and 6 springs in southern Elmore County, southwestern Idaho. These data were collected to characterize the chemical quality of water in major water-yielding zones in areas near Mountain Home and Mountain Home Air Force Base. The data include well and spring locations, well-construction and water level information, and chemical analyses of water from each well and spring inventoried. Groundwater in the study area is generally suitable for most uses. In localized areas, water is highly mineralized, and pH, concentrations of dissolved sulfate, chloride, or nitrite plus nitrate and nitrogen exceed national public drinking-water limits. Fecal coliform and fecal streptococci bacteria were detected in separate water samples. One or more volatile organic compounds were detected in water samples from 15 wells, and the concentration of benzene exceeded the national public drinking-water limit in a water sample from one well. 5 refs., 4 figs., 6 tabs.

  14. Predicting plant uptake of organic chemicals from soil or air using octanol/water and octanol/air partition ratios and a molecular connectivity index

    SciTech Connect

    Dowdy, D.L.; McKone, T.E.

    1997-12-01

    A bioconcentration ratio (BCR) represents the ratio of the concentration of a chemical found in an exposed biological system, such as a plant or fish, to the concentration in the exposure medium (water, soil, or air). A comparison is made of the precision and accuracy of the molecular connectivity index (MCI) and the octanol/water partition coefficient (K{sub ow}) as predictors of BCRs from the soil matrix into above- or below-ground vegetation tissues. Calculated octanol/air partition coefficient (K{sub oa}) values are compared with calculated K{sub ow} and MCI values as predictors of measured air-to-plant BCRs. Based on a statistical evaluation of explained variance, residual error, and cross-validation, this evaluation reveals that the MCI provides higher precision, greater ease of use, and a more cost-effective method for predicting the potential bioconcentration of a chemical from soil into above-ground vegetation. Statistical analyses of the various methods reveal that both the K{sub ow} and MCI approaches have a similar level of precision for predicting BCRs from soil solution into roots and, among MCI, K{sub oa} and K{sub ow}; K{sub oa} is somewhat more precise and valid than MCI and K{sub ow} for estimating uptake, but all have limited accuracy as bioconcentration predictors. These latter results are derived mainly from the paucity of both reliable K{sub oa} values and measured air-to-plant BCRs and indicate a need for more experimental measurements from which more accurate models may be developed.

  15. Day and night variation in chemical composition and toxicological responses of size segregated urban air PM samples in a high air pollution situation

    NASA Astrophysics Data System (ADS)

    Jalava, P. I.; Wang, Q.; Kuuspalo, K.; Ruusunen, J.; Hao, L.; Fang, D.; Väisänen, O.; Ruuskanen, A.; Sippula, O.; Happo, M. S.; Uski, O.; Kasurinen, S.; Torvela, T.; Koponen, H.; Lehtinen, K. E. J.; Komppula, M.; Gu, C.; Jokiniemi, J.; Hirvonen, M.-R.

    2015-11-01

    Urban air particulate pollution is a known cause for adverse human health effects worldwide. China has encountered air quality problems in recent years due to rapid industrialization. Toxicological effects induced by particulate air pollution vary with particle sizes and season. However, it is not known how distinctively different photochemical activity and different emission sources during the day and the night affect the chemical composition of the PM size ranges and subsequently how it is reflected to the toxicological properties of the PM exposures. The particulate matter (PM) samples were collected in four different size ranges (PM10-2.5; PM2.5-1; PM1-0.2 and PM0.2) with a high volume cascade impactor. The PM samples were extracted with methanol, dried and thereafter used in the chemical and toxicological analyses. RAW264.7 macrophages were exposed to the particulate samples in four different doses for 24 h. Cytotoxicity, inflammatory parameters, cell cycle and genotoxicity were measured after exposure of the cells to particulate samples. Particles were characterized for their chemical composition, including ions, element and PAH compounds, and transmission electron microscopy (TEM) was used to take images of the PM samples. Chemical composition and the induced toxicological responses of the size segregated PM samples showed considerable size dependent differences as well as day to night variation. The PM10-2.5 and the PM0.2 samples had the highest inflammatory potency among the size ranges. Instead, almost all the PM samples were equally cytotoxic and only minor differences were seen in genotoxicity and cell cycle effects. Overall, the PM0.2 samples had the highest toxic potential among the different size ranges in many parameters. PAH compounds in the samples and were generally more abundant during the night than the day, indicating possible photo-oxidation of the PAH compounds due to solar radiation. This was reflected to different toxicity in the PM

  16. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    PubMed

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-01

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs. PMID:24678766

  17. CHANGES TO THE CHEMICAL MECHANISMS FOR HAZARDOUS AIR POLLUTANTS IN CMAQ VERSION 4.6

    EPA Science Inventory

    The extended abstract describes a presentation to the 2006 conference of the Community Modeling and Analysis System. The presentation introduces two new mechanisms for the atmospheric photochemistry of Hazardous Air Pollutants (HAPs) to be used in regional air quality models. It ...

  18. Improvement on the concentrated grape juice physico-chemical characteristics by an enzymatic treatment and Membrane Separation Processes.

    PubMed

    Campos, Plínio R F; Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Trigueros, Daniela E G; Barros, Sueli T D; Pereira, Nehemias C

    2016-03-01

    In this work, the improvement on the concentrated grape juice physico-chemical characteristics by using an enzymatic treatment followed by Membrane Separation Process (MSP) has been investigated. By using Novozym 33095(r) and Ultrazym AFP L(r) enzymes varying three operating parameters, the best result on the grape pulp characteristics was attained for the Novozym 33095(r) performed at 35oC, 15 min. and 50 mgL-1. In micro/ultra filtration processes after enzymatic pretreatment, the best performance of the MSP with high permeate flux value and suitable grape juice characteristics was attained using 0.05 mm membrane pore size, 1 bar pressure and 40 oC treatment temperature. When reverse osmosis process is operated at 40 bar and 40oC, high soluble solid and low turbidity values are attained. An enzymatic treatment along with MSP has shown an alternative and efficient grape juice processing system, being possible to extend to other foods. PMID:26959316

  19. Title III list of lists: Consolidated list of chemicals subject to the Emergency Planning and Community Right-to-Know Act (EPCRA) and section 112(r) of the Clean Air Act, as amended. Title III of the Superfund Amendments and Reauthorization Act of 1986, and Title III of the Clean Air Act Amendments of 1990

    SciTech Connect

    Not Available

    1994-06-01

    The consolidated chemical list includes chemicals subject to reporting requirements under Title III of the Superfund Amendments and Reauthorization Act of 1986 (SARA), also known as the Emergency Planning and Community Right-to-Know Act (EPCRA), and chemicals listed under section 112(r) of Title III the Clean Air Act (CAA) Amendments of 1990. This consolidated list has been prepared to help firms handling chemicals determine whether they need to submit reports under sections 302, 304, or 313 of SARA Title III (EPCRA) and, for a specific chemical, what reports may need to be submitted. Separate lists are also provided of Resource Conservation and Recovery Act (RCRA) waste streams and unlisted hazardous wastes, and of radionuclides reportable under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). These lists should be used as reference tool, not as a definitive source of compliance information. The chemicals on the consolidated list are ordered by Chemical Abstract Service (CAS) registry number. Categories of chemicals, which do not have CAS registry numbers, but which are cited under CERCLA, EPCRA section 313, and the CAA, are placed at the end of the list. More than one chemical name may be listed for one CAS number, because the same chemical may appear on different lists under different names.

  20. Hydrogeo-chemical impacts of air sparging remediation on a semi-confined aquifer: evidences from field monitoring and modeling.

    PubMed

    Fan, W; Yang, Y S; Lu, Y; Du, X Q; Zhang, G X

    2013-01-01

    Air sparging (AS) was explored for remediation of a petroleum contaminated semi-confined groundwater system in NE China. Physical, hydro-chemical and hydraulic behaviors in subsurface environment during AS were investigated with support of modeling to understand the hydrogeo-chemical impacts of AS on the aquifer. The responses of groundwater, dissolved oxygen and temperature indicated that the radius of influence of AS was up to 8-9 m, and a 3D boundary of the zone of influence (ZOI) was accordingly obtained with volume of 362 m(3). Water mounding unlike normal observations was featured by continuous up-lift and blocked dissipation. AS induced water displacement was calculated showing no obvious spreading of contaminant plume under this AS condition. Slug tests were employed before and after AS to reveal that the physical perturbation led to sharp increase in permeability and porosity. Modeling indicated that the regional groundwater flow field was not affected by AS except the physical perturbation in ZOI. Hydro-chemically increase of pH and Eh, and reduction of TDS, electrical conductivity and bicarbonate were observed in ZOI during AS. PHREEQC modeling inferred that these chemical phenomena were induced by the inorganic carbon transfer during air mixing. PMID:23021385

  1. Organochlorine pesticides in soils and air of southern Mexico: Chemical profiles and potential for soil emissions

    NASA Astrophysics Data System (ADS)

    Wong, Fiona; Alegria, Henry A.; Jantunen, Liisa M.; Bidleman, Terry F.; Salvador-Figueroa, Miguel; Gold-Bouchot, Gerardo; Ceja-Moreno, Victor; Waliszewski, Stefan M.; Infanzon, Raul

    The extent of organochlorine pesticides (OCs) contamination in southern Mexico was investigated in this study. Biweekly air samplings were carried out in two sites in the state of Chiapas (during 2002-2003), and one in each state of Veracruz and Tabasco (during 2003-2004). Corresponding to the air sampling locations, soil samples were also collected to gauge the soil-air exchange of OCs in the region. ∑DDTs in soils ranged from 0.057 to 360 ng g -1 whereas those in air ranged from 240 to 2400 pg m -3. DDT and metabolite DDE were expressed as fractional values, FDDTe = p, p'-DDT/( p, p'-DDT + p, p'-DDE) and FDDTo = p,p'-DDT/( p,p'-DDT + o,p'-DDT). FDDTe in soils ranged from 0.30 to 0.69 while those in air ranged from 0.45 to 0.84. FDDTe in air at a farm in Chiapas (0.84) was closer to that of technical DDT (0.95) which is suggestive of fresh DDT input. Enantiomer fractions (EF) of o,p'-DDT in air were racemic at all locations (0.500-0.504). However, nonracemic o,p'-DDT was seen in the soils (EFs = 0.456-0.647). Fugacities of OCs in soil ( fs) and air ( fa) were calculated, and the fugacity fraction, ff = fs/( fs + fa) of DDTs ranged from 0.013 to 0.97 which indicated a mix of net deposition ( ff < 0.5) and volatilization ( ff > 0.5) from soil among the sites. It is suggested that DDTs in Mexico air are due to a combination of ongoing regional usage and re-emission of old DDT residues from soils. Total toxaphene in soils ranged from 0.066 to 69 ng g -1 while levels in air ranged from 6.2 to 230 pg m -3. Chromatographic profiles of toxaphenes in both air and soil showed depletion of Parlar congeners 39 and 42. Fugacity fractions of toxaphene were within the equilibrium range or above the upper equilibrium threshold boundary. These findings suggested that soil emission of old residues is the main source of toxaphenes to the atmosphere. Results from this study provide baseline data for establishing a long-term OC monitoring program in Mexico.

  2. Non-Chemical Stressors and Cumulative Risk Assessment: An Overview of Current Initiatives and Potential Air Pollutant Interactions

    PubMed Central

    Lewis, Ari S.; Sax, Sonja N.; Wason, Susan C.; Campleman, Sharan L.

    2011-01-01

    Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit

  3. Development of open air silicon deposition technology by silane-free atmospheric pressure plasma enhanced chemical transport under local ambient gas control

    NASA Astrophysics Data System (ADS)

    Naito, Teruki; Konno, Nobuaki; Yoshida, Yukihisa

    2016-07-01

    Open air silicon deposition was performed by combining silane-free atmospheric pressure plasma-enhanced chemical transport and a newly developed local ambient gas control technology. The effect of air contamination on silicon deposition was investigated using a vacuum chamber, and the allowable air contamination level was confirmed to be 3 ppm. The capability of the local ambient gas control head was investigated numerically and experimentally. A safe and clean process environment with air contamination less than 1 ppm was achieved. Combining these technologies, a microcrystalline silicon film was deposited in open air, the properties of which were comparable to those of silicon films deposited in a vacuum chamber.

  4. Method for Fusing Observational Data and Chemical Transport Model Simulations To Estimate Spatiotemporally Resolved Ambient Air Pollution.

    PubMed

    Friberg, Mariel D; Zhai, Xinxin; Holmes, Heather A; Chang, Howard H; Strickland, Matthew J; Sarnat, Stefanie Ebelt; Tolbert, Paige E; Russell, Armistead G; Mulholland, James A

    2016-04-01

    Investigations of ambient air pollution health effects rely on complete and accurate spatiotemporal air pollutant estimates. Three methods are developed for fusing ambient monitor measurements and 12 km resolution chemical transport model (CMAQ) simulations to estimate daily air pollutant concentrations across Georgia. Temporal variance is determined by observations in one method, with the annual mean CMAQ field providing spatial structure. A second method involves scaling daily CMAQ simulated fields using mean observations to reduce bias. Finally, a weighted average of these results based on prediction of temporal variance provides optimized daily estimates for each 12 × 12 km grid. These methods were applied to daily metrics of 12 pollutants (CO, NO2, NOx, O3, SO2, PM10, PM2.5, and five PM2.5 components) over the state of Georgia for a seven-year period (2002-2008). Cross-validation demonstrates a wide range in optimized model performance across pollutants, with SO2 predicted most poorly due to limitations in coal combustion plume monitoring and modeling. For the other pollutants studied, 54-88% of the spatiotemporal variance (Pearson R(2) from cross-validation) was captured, with ozone and PM2.5 predicted best. The optimized fusion approach developed provides daily spatial field estimates of air pollutant concentrations and uncertainties that are consistent with observations, emissions, and meteorology. PMID:26923334

  5. EXPOSURE-DOSE-EFFECT LINKAGES FOR CHEMICALLY REACTIVE AIR TOXIC COMPOUNDS

    EPA Science Inventory

    This project represents a multidisciplinary collaboration to develop and test methods for more precisely predicting human exposure-dose-response relationships of respiratory tract irritants. These irritants have the unique property of reacting chemically with proteins and lipids ...

  6. PREVENTION REFERENCE MANUAL: CHEMICAL SPECIFIC. VOLUME 3. CONTROL OF ACCIDENTAL RELEASES OF HYDROGEN CYANIDE (SCAQMD) (SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT)

    EPA Science Inventory

    The report discusses a strategy (being considered by the South Coast Air Quality Management District--SCAQMD--of Southern California) for reducing the risk of a major accidental air release of toxic chemicals. The strategy, intended to guide both industry and communities, consist...

  7. Combustion of hydrogen-air jets in local chemical equilibrium: A guide to the CHARNAL computer program

    NASA Technical Reports Server (NTRS)

    Spalding, D. B.; Launder, B. E.; Morse, A. P.; Maples, G.

    1974-01-01

    A guide to a computer program, written in FORTRAN 4, for predicting the flow properties of turbulent mixing with combustion of a circular jet of hydrogen into a co-flowing stream of air is presented. The program, which is based upon the Imperial College group's PASSA series, solves differential equations for diffusion and dissipation of turbulent kinetic energy and also of the R.M.S. fluctuation of hydrogen concentration. The effective turbulent viscosity for use in the shear stress equation is computed. Chemical equilibrium is assumed throughout the flow.

  8. Effects of air injection during sap processing on maple syrup color, chemical composition and flavor volatiles.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Air injection (AI) is a maple sap processing technology reported to increase the efficiency of maple syrup production by increasing production of more economically valuable light-colored maple syrup, and reducing development of loose scale mineral precipitates in syrup, and scale deposits on evapora...

  9. SIMULATING REGIONAL-SCALE AIR QUALITY WITH DYNAMIC CHANGES IN REGIONAL CLIMATE AND CHEMICAL BOUNDARY CONDITIONS

    EPA Science Inventory

    This poster compares air quality modeling simulations under current climate and a future (approximately 2050) climate scenario. Differences in predicted ozone episodes and daily average PM2.5 concentrations are presented, along with vertical ozone profiles. Modeling ...

  10. ENHANCED AIR POLLUTION EPIDEMIOLOGY USING A SOURCE-ORIENTED CHEMICAL TRANSPORT MODEL

    EPA Science Inventory

    Air quality model predictions describing source-oriented PM component concentrations in multiple size cuts will provide new inputs to examine the effects of acute and chronic PM exposure on mortality and morbidity. Associations between adverse health effects and PM sources/com...

  11. The promising chemical kinetics for the simulation of propane-air combustion with KIVA-II code

    NASA Technical Reports Server (NTRS)

    Ying, S. J.; Gorla, Rama S. R.; Kundu, Krishna P.

    1993-01-01

    The development of chemical kinetics for the simulation of propane-air combustion with the use of computer code KIVA-II since 1989 is summarized here. In order to let readers understand the general feature well, a brief description of the KIVA-II code, specially related with the chemical reactions is also given. Then the results of recent work with 20 reaction mechanism is presented. It is also compared with the 5 reaction mechanism. It may be expected that the numerical stability of the 20 reaction mechanism is better as compared to that of 5 reaction mechanism, but the CPU time of the CRAY computer is much longer. Details are presented in the paper.

  12. Separation processes: Playing a critical role

    SciTech Connect

    Humphrey, J.L.

    1995-10-01

    Separation processes are the main cog in the manufacturing well of the chemical process industries (CPI). They are used for such essential chores as removal of contaminants from raw materials, recovery and purification of primary products, and elimination of contaminants from effluent water and air streams. This article provides an overview of key separation processes, highlights recent commercial developments, and provides insights on expected new developments. It focuses o the core processes for fluid mixture separations--distillation, extraction, adsorption, membranes, and their hybrid systems. Other important processes, such as crystallization and fluid/particle separations, are left for others to cover. 40 refs., 8 figs., 4 tabs.

  13. Chemically modified polymeric resins for separation of cations, organic acids, and small polar moleculea by high performance liquid chromatography

    SciTech Connect

    Morris, J.B.

    1993-07-01

    This thesis is divided into 4 parts: a review, ion chromatography of metal cations on carboxylic resins, separation of hydrophilic organic acids and small polar compounds on macroporous resin columns, and use of eluent modifiers for liquid chromatographic separation of carboxylic acids using conductivity detection.

  14. Influence of Interface Structure on Chemical Etching Process for Air Gap of Microelectromechanical System Based on Surface Micromachining

    NASA Astrophysics Data System (ADS)

    Yoon, Young; Kim, Joon; Polla, Dennis.; Shin, Young

    1998-12-01

    This paper analyses the problems posed by the interface structure during chemical etching by Hydro-fluoric (HF) acid for creating air gaps in microelectromechnical system (MEMS) devices using PZT(53/47) films and surface micromachining techniques. In order to investigate the influence of interface structure on the HF chemical etching process, Pt/PZT/Pt/Ti/TiO2/polysilicon/Si3N4/PSG/Si (Samples A and C) and Pt/PZT/RuO2/Ru/Si3N4/PSG/Si (Sample B) structures were fabricated. These structures are selected for a microcantilever beam and/or an uncooled IR detectors fabricated with PZT piezoelectric/pyroelectric films based on the surface micromachining technique. Both need etching for the removal of phosphor silicate glass (PSG) to create an air gap. If the devices had a poor interface structure, they would fail during the HF chemical etching process because the poor interface structure would act as a kind of penetration path for etching acid leading to unwanted etching. Therefore, it is very important to investigate the interface structure to fabricate efficient MEMS devices. In this study two different solutions have been suggested to improve the interface structure. The first is post thermal annealing at 900°C for 30 min. after deposition of polycrystalline silicon for sample A. Secondly, a RuO2/Ru hybrid electrode was deposited on Si3N4 directly instead of on the Pt/Ti/TiO2/Polysilicon electrode, which has Pt/PZT/RuO2/Ru/Si3N4/PSG/Si as the device structure. These two solutions suggest that a dense interface structure increases enhances of success of the chemical etching process of MEMS devices fabricated using PZT films and surface micromachining techniques.

  15. Separate and Unequal: Residential Segregation and Estimated Cancer Risks Associated with Ambient Air Toxics in U.S. Metropolitan Areas

    PubMed Central

    Morello-Frosch, Rachel; Jesdale, Bill M.

    2006-01-01

    This study examines links between racial residential segregation and estimated ambient air toxics exposures and their associated cancer risks using modeled concentration estimates from the U.S. Environmental Protection Agency’s National Air Toxics Assessment. We combined pollutant concentration estimates with potencies to calculate cancer risks by census tract for 309 metropolitan areas in the United States. This information was combined with socioeconomic status (SES) measures from the 1990 Census. Estimated cancer risks associated with ambient air toxics were highest in tracts located in metropolitan areas that were highly segregated. Disparities between racial/ethnic groups were also wider in more segregated metropolitan areas. Multivariate modeling showed that, after controlling for tract-level SES measures, increasing segregation amplified the cancer risks associated with ambient air toxics for all racial groups combined [highly segregated areas: relative cancer risk (RCR) = 1.04; 95% confidence interval (CI), 1.01–107; extremely segregated areas: RCR = 1.32; 95% CI, 1.28–1.36]. This segregation effect was strongest for Hispanics (highly segregated areas: RCR = 1.09; 95% CI, 1.01–1.17; extremely segregated areas: RCR = 1.74; 95% CI, 1.61–1.88) and weaker among whites (highly segregated areas: RCR = 1.04; 95% CI, 1.01–1.08; extremely segregated areas: RCR = 1.28; 95% CI, 1.24–1.33), African Americans (highly segregated areas: RCR = 1.09; 95% CI, 0.98–1.21; extremely segregated areas: RCR = 1.38; 95% CI, 1.24–1.53), and Asians (highly segregated areas: RCR = 1.10; 95% CI, 0.97–1.24; extremely segregated areas: RCR = 1.32; 95% CI, 1.16–1.51). Results suggest that disparities associated with ambient air toxics are affected by segregation and that these exposures may have health significance for populations across racial lines. PMID:16507462

  16. Reduced and simplified chemical kinetics for air dissociation using Computational Singular Perturbation

    NASA Technical Reports Server (NTRS)

    Goussis, D. A.; Lam, S. H.; Gnoffo, P. A.

    1990-01-01

    The Computational Singular Perturbation CSP methods is employed (1) in the modeling of a homogeneous isothermal reacting system and (2) in the numerical simulation of the chemical reactions in a hypersonic flowfield. Reduced and simplified mechanisms are constructed. The solutions obtained on the basis of these approximate mechanisms are shown to be in very good agreement with the exact solution based on the full mechanism. Physically meaningful approximations are derived. It is demonstrated that the deduction of these approximations from CSP is independent of the complexity of the problem and requires no intuition or experience in chemical kinetics.

  17. Extinction of premixed H{sub 2}/air flames: Chemical kinetics and molecular diffusion effects

    SciTech Connect

    Dong, Yufei; Holley, Adam T.; Andac, Mustafa G.; Egolfopoulos, Fokion N.; Wang, Hai; Davis, Scott G.; Middha, Prankul

    2005-09-01

    Laminar flame speed has traditionally been used for the partial validation of flame kinetics. In most cases, however, its accurate determination requires extensive data processing and/or extrapolations, thus rendering the measurement of this fundamental flame property indirect. Additionally, the presence of flame front instabilities does not conform to the definition of laminar flame speed. This is the case for Le<1 flames, with the most notable example being ultralean H{sub 2}/air flames, which develop cellular structures at low strain rates so that determination of laminar flame speeds for such mixtures is not possible. Thus, this low-temperature regime of H{sub 2} oxidation has not been validated systematically in flames. In the present investigation, an alternative/supplemental approach is proposed that includes the experimental determination of extinction strain rates for these flames, and these rates are compared with the predictions of direct numerical simulations. This approach is meaningful for two reasons: (1) Extinction strain rates can be measured directly, as opposed to laminar flame speeds, and (2) while the unstretched lean H{sub 2}/air flames are cellular, the stretched ones are not, thus making comparisons between experiment and simulations meaningful. Such comparisons revealed serious discrepancies between experiments and simulations for ultralean H{sub 2}/air flames by using four kinetic mechanisms. Additional studies were conducted for lean and near-stoichiometric H{sub 2}/air flames diluted with various amounts of N{sub 2}. Similarly to the ultralean flames, significant discrepancies between experimental and predicted extinction strain rates were also found. To identify the possible sources of such discrepancies, the effect of uncertainties on the diffusion coefficients was assessed and an improved treatment of diffusion coefficients was advanced and implemented. Under the conditions considered in this study, the sensitivity of diffusion

  18. The chemical instability of Na{sub 2}IrO{sub 3} in air

    SciTech Connect

    Krizan, J.W. Roudebush, J.H.; Fox, G.M.; Cava, R.J.

    2014-04-01

    Highlights: • Na{sub 2}IrO{sub 3} decomposes rapidly in laboratory air. • The decomposition requires the simultaneous presence of CO{sub 2} and H{sub 2}O. • Decomposition results in a dramatic change in the magnetic properties. • Second 5 K feature in magnetic susceptibility not previously reported. - Abstract: We report that Na{sub 2}IrO{sub 3}, which has a layered honeycomb iridium oxide sublattice interleaved by Na planes, decomposes in laboratory air while maintaining the same basic crystal structure. The decomposition reaction was monitored by time-dependent powder X-ray diffraction under different ambient atmospheres, through which it was determined that it occurs only in the simultaneous presence of both CO{sub 2} and H{sub 2}O. A hydrated sodium carbonate is the primary decomposition product along with altered Na{sub 2}IrO{sub 3}. The diffraction signature of the altered Na{sub 2}IrO{sub 3} is quite similar to that of the pristine material, which makes the detection of decomposition difficult in a sample handled under ordinary laboratory conditions. The decomposed samples show a significantly decreased magnetic susceptibility and the disappearance of the low temperature antiferromagnetic transition considered to be characteristic of the phase. Samples that have never been exposed to air after synthesis display a previously unreported magnetic transition at 5 K.

  19. Flow processes in overexpanded chemical rocket nozzles. Part 3: Methods for the aimed flow separation and side load reduction

    NASA Technical Reports Server (NTRS)

    Schmucker, R. H.

    1983-01-01

    Methods aimed at reduction of overexpansion and side load resulting from asymmetric flow separation for rocket nozzles with a high opening ratio are described. The methods employ additional measures for nozzles with a fixed opening ratio. The flow separation can be controlled by several types of nozzle inserts, the properties of which are discussed. Side loads and overexpansion can be reduced by adapting the shape of the nozzle and taking other additional measures for controlled separation of the boundary layer, such as trip wires.

  20. Air is still contaminated 40 years after the Michigan Chemical plant disaster in St. Louis, Michigan.

    PubMed

    Peverly, Angela A; Salamova, Amina; Hites, Ronald A

    2014-10-01

    The Michigan Chemical (also known as Velsicol Chemical) plant located in St. Louis, Michigan operated from 1936-1978. During this time, the plant manufactured polybrominated biphenyls (PBBs), hexabromobenzene (HBB), 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), and tris(2,3-dibromopropyl) phosphate (TDBPP), among other products. Due to widespread PBB contamination of Michigan, the plant eventually became a Superfund site, and despite years of cleanup activities, many of the compounds can still be found in the local ecosystem. To investigate the current atmospheric levels and to determine their spatial distributions, we collected tree bark samples from around Michigan and measured the concentrations of these pollutants. For comparison, other organic pollutants, such as polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs), which were not manufactured at the Michigan Chemical plant, were also measured in the same tree bark samples. Our results show levels of PBBs, DDT, and HBB in tree bark collected within 10 km of the Velsicol Superfund site (43, 477, and 108 ng/g lipid wgt., respectively) are 1-2 orders of magnitude higher than at sites located more than 10 km from the site (0.36, 28, and 0.36 ng/g lipid wgt., respectively). Levels of PBDEs and OPEs did not depend on distance from St. Louis. This is the first study on the atmospheric distribution of these chemicals around the Superfund site. PMID:25211223

  1. The Relationship between Odour Annoyance Scores and Modelled Ambient Air Pollution in Sarnia, “Chemical Valley”, Ontario

    PubMed Central

    Atari, Dominic Odwa; Luginaah, Isaac N.; Fung, Karen

    2009-01-01

    This study aimed at establishing the relationship between annoyance scores and modelled air pollution in “Chemical Valley”, Sarnia, Ontario (Canada). Annoyance scores were taken from a community health survey (N = 774); and respondents’ exposure to nitrogen dioxide (NO2) and sulphur dioxide (SO2) were estimated using land use regression (LUR) models. The associations were examined by univariate analysis while multivariate logistic regression was used to examine the determinants of odour annoyance. The results showed that odour annoyance was significantly correlated to modelled pollutants at the individual (NO2, r = 0.15; SO2, r = 0.13) and census tract (NO2, r = 0.56; SO2, r = 0.67) levels. The exposure-response relationships show that residents of Sarnia react to very low pollution concentrations levels even if they are within the Ontario ambient air quality criteria. The study found that exposure to high NO2 and SO2 concentrations, gender, and perception of health effects were significant determinants of individual odour annoyance reporting. The observed association between odour annoyance and modelled ambient pollution suggest that individual and census tract level annoyance scores may serve as proxies for air quality in exposed communities because they capture the within area spatial variability of pollution. However, questionnaire-based odour annoyance scores need to be validated longitudinally and across different scales if they are to be adopted for use at the national level. PMID:20054461

  2. Multi-step approach for comparing the local air pollution contributions of conventional and innovative MSW thermo-chemical treatments.

    PubMed

    Ragazzi, M; Rada, E C

    2012-10-01

    In the sector of municipal solid waste management the debate on the performances of conventional and novel thermo-chemical technologies is still relevant. When a plant must be constructed, decision makers often select a technology prior to analyzing the local environmental impact of the available options, as this type of study is generally developed when the design of the plant has been carried out. Additionally, in the literature there is a lack of comparative analyses of the contributions to local air pollution from different technologies. The present study offers a multi-step approach, based on pollutant emission factors and atmospheric dilution coefficients, for a local comparative analysis. With this approach it is possible to check if some assumptions related to the advantages of the novel thermochemical technologies, in terms of local direct impact on air quality, can be applied to municipal solid waste treatment. The selected processes concern combustion, gasification and pyrolysis, alone or in combination. The pollutants considered are both carcinogenic and non-carcinogenic. A case study is presented concerning the location of a plant in an alpine region and its contribution to the local air pollution. Results show that differences among technologies are less than expected. Performances of each technology are discussed in details. PMID:22795304

  3. Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion

    NASA Technical Reports Server (NTRS)

    Carson, G. T., Jr.

    1974-01-01

    Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

  4. Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

    NASA Astrophysics Data System (ADS)

    Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

    2016-04-01

    The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N2 and 20% O2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 1013 cm-3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the flash

  5. Nanoscale chemical phase separation in FeTe0.55Se0.45 as seen via scanning tunneling spectroscopy

    NASA Astrophysics Data System (ADS)

    He, Xiaobo; Li, Guorong; Zhang, Jiandi; Karki, A. B.; Jin, Rongying; Sales, B. C.; Sefat, A. S.; McGuire, M. A.; Mandrus, D.; Plummer, E. W.

    2011-06-01

    Atomically resolved structural and electronic properties of FeTe1-xSex (x = 0 and 0.45) have been studied with scanning tunneling microscopy/spectroscopy (STM/STS). In contrast to the extreme flatness of the Te-terminated FeTe surface, nanoscale chemical phase separation between Te and Se atoms is unambiguously revealed on the surface of FeTe0.55Se0.45. A statistical counting of the two kinds of atoms has the same ratio as that in the bulk. Remarkably, there is no electronic phase separation seen in the tunneling spectroscopy. This indicates that the optimally doped superconductor is chemically inhomogeneous but electronically homogeneous, in contrast to many correlated electron materials.

  6. Blood Pressure Changes and Chemical Constituents of Particulate Air Pollution: Results from the Healthy Volunteer Natural Relocation (HVNR) Study

    PubMed Central

    Wu, Shaowei; Deng, Furong; Huang, Jing; Wang, Hongyi; Shima, Masayuki; Wang, Xin; Qin, Yu; Zheng, Chanjuan; Wei, Hongying; Hao, Yu; Lv, Haibo; Lu, Xiuling

    2012-01-01

    Background: Elevated blood pressure (BP) has been associated with particulate matter (PM) air pollution, but associations with PM chemical constituents are still uncertain. Objectives: We investigated associations of BP with various chemical constituents of fine PM (PM2.5) during 460 repeated visits among a panel of 39 university students. Methods: Resting BP was measured using standardized methods before and after the university students relocated from a suburban campus to an urban campus with different air pollution contents in Beijing, China. Air pollution data were obtained from central monitors close to student residences. We used mixed-effects models to estimate associations of various PM2.5 constituents with systolic BP (SBP), diastolic BP (DBP), and pulse pressure. Results: An interquartile range increase of 51.2 μg/m3 in PM2.5 was associated with a 1.08-mmHg (95% CI: 0.17, 1.99) increase in SBP and a 0.96-mmHg (95% CI: 0.31, 1.61) increase in DBP on the following day. A subset of PM2.5 constituents, including carbonaceous fractions (organic carbon and elemental carbon), ions (chloride and fluoride), and metals/metalloid elements (nickel, zinc, magnesium, lead, and arsenic), were found to have robust positive associations with different BP variables, though robust negative associations of manganese, chromium, and molybdenum with SBP or DBP also were observed. Conclusions: Our results support relationships between specific PM2.5 constituents and BP. These findings have potential implications for the development of pollution abatement strategies that maximize public health benefits. PMID:23086577

  7. Multivariate analysis of respiratory problems and their connection with meteorological parameters and the main biological and chemical air pollutants

    NASA Astrophysics Data System (ADS)

    Matyasovszky, István; Makra, László; Bálint, Beatrix; Guba, Zoltán; Sümeghy, Zoltán

    2011-08-01

    The aim of the study is to analyse the joint effect of biological (pollen) and chemical air pollutants, as well as meteorological variables, on the hospital admissions of respiratory problems for the Szeged region in Southern Hungary. The data set used covers a nine-year period (1999-2007) and is unique in the sense that it includes—besides the daily number of respiratory hospital admissions—not just the hourly mean concentrations of CO, PM 10, NO, NO 2, O 3 and SO 2 with meteorological variables (temperature, global solar flux, relative humidity, air pressure and wind speed), but two pollen variables ( Ambrosia and total pollen excluding Ambrosia) as well. The analysis was performed using three age categories for the pollen season of Ambrosia and the pollen-free season. Meteorological elements and air pollutants are clustered in order to define optimum environmental conditions of high patient numbers. ANOVA was then used to determine whether cluster-related mean patient numbers differ significantly. Furthermore, two novel procedures are applied here: factor analysis including a special transformation and a time-varying multivariate linear regression that makes it possible to determine the rank of importance of the influencing variables in respiratory hospital admissions, and also compute the relative importance of the parameters affecting respiratory disorders. Both techniques revealed that Ambrosia pollen is an important variable that influences hospital admissions (an increase of 10 pollen grains m -3 can imply an increase of around 24% in patient numbers). The role of chemical and meteorological parameters is also significant, but their weights vary according to the seasons and the methods. Clearer results are obtained for the pollination season of Ambrosia. Here, a 10 μg m -3 increase in O 3 implies a patient number response from -17% to +11%. Wind speed is a surprisingly important variable, where a 1 m s -1 rise may result in a hospital admission

  8. Chemical compositions and radiative properties of dust and anthropogenic air masses study in Taipei Basin, Taiwan, during spring of 2004

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Yu; Fang, Guor-Cheng; Chou, Charles C.-K.; Chen, Wei-Nai

    Asia is one of the major sources of not only mineral dust but also anthropogenic aerosols. Continental air masses associated with the East Asian winter monsoon always contain high contents of mineral dust and anthropogenic species and transported southeastward to Taiwan, which have significant influences on global atmospheric radiation transfer directly by scattering and absorbing solar radiation in each spring. However, few measurements for the long-range transported aerosol and its optical properties were announced in this area, between the Western Pacific and the southeastern coast of Mainland China. The overall objective of this work is to quantify the optical characteristics of different aerosol types in the Eastern Asian. In order to achieve this objective, meteorological parameters, concentrations of PM 10 and its soluble species, and optical property of atmospheric scattering coefficients were measured continuously with 1 h time-resolved from 11 February to 7 April 2004 in Taipei Basin (25°00'N, 121°32'E). In this work, the dramatic changes of meteorological parameters such as temperature and winds were used to determine the influenced period of each air mass. Continental, strong continental, marine, and stagnant air masses defined by the back-trajectory analysis and local meteorology were further characterized as long-range transport pollution, dust, clean marine, and local pollution aerosols, respectively, according to the diagnostic ratios. The aerosol mass scattering efficiency of continental pollution, dust, clean marine, and local pollution aerosols were ranged from 1.3 to 1.6, 0.7 to 1.0, 1.4 and 1.4 to 2.3 m 2 g -1, respectively. Overall, there are two distinct populations of aerosol mass scattering efficiencies, one for an aerosol chemical composition dominated by dust (<1.0 m 2 g -1) and the other for an aerosol chemical composition dominated by anthropogenic pollutants (1.3-2.3 m 2 g -1), which were similar to the previous measurements with

  9. Chemical Transport and Reduced-Form Models for Assessing Air Quality Impacts of Current and Future Energy Scenarios

    NASA Astrophysics Data System (ADS)

    Adams, P. J.

    2015-12-01

    Though essential for informed decision-making, it is challenging to estimate the air quality and public health impacts associated with current and future energy generation scenarios because the analysis must address the complicated atmospheric processes that air pollutants undergo: emissions, dispersion, chemistry, and removal. Employing a chemical transport model (CTM) is the most rigorous way to address these atmospheric processes. However, CTMs are expensive from a computational standpoint and, therefore, beyond the reach of policy analysis for many types of problems. On the other hand, previously available reduced-form models used for policy analysis fall short of the rigor of CTMs and may lead to biased results. To address this gap, we developed the Estimating Air pollution Social Impacts Using Regression (EASIUR) method, which builds parameterizations that predict per-tonne social costs and intake fractions for pollutants emitted from any location in the United States. Derived from a large database of tagged CTM simulations, the EASIUR method predicts social costs almost indistinguishable from a full CTM but with negligible computational requirements. We found that the average mortality-related social costs from inorganic PM2.5 and its precursors in the United States are 150,000-180,000/t EC, 21,000-34,000/t SO2, 4,200-15,000/t NOx, and 29,000-85,000/t NH3. This talk will demonstrate examples of using both CTMs and reduced-form models for assessing air quality impacts associated with current energy production activities as well as a future deployment of carbon capture and sequestration.

  10. Screening-level models to estimate partition ratios of organic chemicals between polymeric materials, air and water.

    PubMed

    Reppas-Chrysovitsinos, Efstathios; Sobek, Anna; MacLeod, Matthew

    2016-06-15

    Polymeric materials flowing through the technosphere are repositories of organic chemicals throughout their life cycle. Equilibrium partition ratios of organic chemicals between these materials and air (KMA) or water (KMW) are required for models of fate and transport, high-throughput exposure assessment and passive sampling. KMA and KMW have been measured for a growing number of chemical/material combinations, but significant data gaps still exist. We assembled a database of 363 KMA and 910 KMW measurements for 446 individual compounds and nearly 40 individual polymers and biopolymers, collected from 29 studies. We used the EPI Suite and ABSOLV software packages to estimate physicochemical properties of the compounds and we employed an empirical correlation based on Trouton's rule to adjust the measured KMA and KMW values to a standard reference temperature of 298 K. Then, we used a thermodynamic triangle with Henry's law constant to calculate a complete set of 1273 KMA and KMW values. Using simple linear regression, we developed a suite of single parameter linear free energy relationship (spLFER) models to estimate KMA from the EPI Suite-estimated octanol-air partition ratio (KOA) and KMW from the EPI Suite-estimated octanol-water (KOW) partition ratio. Similarly, using multiple linear regression, we developed a set of polyparameter linear free energy relationship (ppLFER) models to estimate KMA and KMW from ABSOLV-estimated Abraham solvation parameters. We explored the two LFER approaches to investigate (1) their performance in estimating partition ratios, and (2) uncertainties associated with treating all different polymers as a single "bulk" polymeric material compartment. The models we have developed are suitable for screening assessments of the tendency for organic chemicals to be emitted from materials, and for use in multimedia models of the fate of organic chemicals in the indoor environment. In screening applications we recommend that KMA and KMW be

  11. Chemical Extraction of Carbon Dioxide From Air: A Strategy to Avoid Climate Change and Sustain Fossil Energy?

    NASA Astrophysics Data System (ADS)

    Dubey, M. K.; Ziock, H.; Rueff, G.; Colman, J.; Smith, W. S.

    2002-12-01

    analyzed by X ray diffraction and thermal gravimetric analysis. We identify the atmospheric sub-laminar boundary layer and the stagnant liquid surface as potential barriers to CO2 uptake. Strategies to overcome these limits are developed. We discuss other renewable, energy efficient, and effective CO2 scrubbers with lower binding energies. High-resolution simulations are also being performed to characterize the effects of atmospheric mixing, size and geometry of extractors on the collection efficiency. Capture of CO2 from air is a promising long term strategy to sustain fossil energy use by avoiding climate change but much research and development is needed to implement it. [1] Elliott S. et al.,Compensation of atmospheric CO2 buildup through engineered chemical sinkage, Geophys. Res. Lett., 28(7), 1235-1238, 2001. [2] Dubey, M. K. et al., Extraction of carbon dioxide from the atmosphere through engineered chemical sinkage, 2002 American Chemical Society, Division of Fuel Chemistry Preprints, 47(1), 81-84, 2002. [3] Johnston, et al. Chemical Transport Modeling of Potential Atmospheric Carbon Dioxide Sinks, in press Energy Conversion & Management, 2002.

  12. Model of phase distribution of hydrophobic organic chemicals in cyclodextrin-water-air-solid sorbent systems as a function of salinity, temperature, and the presence of multiple CDs

    NASA Astrophysics Data System (ADS)

    Blanford, W. J.

    2013-12-01

    Environmental and other applications of cyclodextrins (CD) often require usage of high concentra- tion aqueous solutions of derivatized CDs. In an effort to reduce the costs, these studies also typically use technical grades where the purity of the CD solution and the degree of substitution has not been reported. Further, this grade of CD often included high levels of salt and it is commonly applied in high salinity systems. The mathematical models for water and air partitioning coefficients of hydrophobic organic chemicals (HOC) with CDs that have been used in these studies under-estimate the level of HOC within CDs. This is because those models (1) do not take into account that high concentrations of CDs result in significantly lower levels of water in solution and (2) they do not account for the reduction in HOC aqueous solubility due to the presence of salt. Further, because they have poor knowledge of the CD molar concentration in their solu- tions, it is difficult to draw comparisons between studies. Herein is developed a mathematical model where cyclo- dextrin is treated as a separate phase whose relative volume is calculated from its apparent molar volume in solution and the CD concentration of the solution. The model also accounts for the affects of temperature and the presence of salt in solution through inclusion of modified versions of the Van't Hoff and Setschenow equations. With these capabilities, additional equations have been developed for calculating HOC phase distribution in air-water-CD-solid sorbent systems for a single HOC and between water and CD for a system containing multiple HOCs as well as multiple types of cyclodextrin.

  13. Topographical and Chemical Imaging of a Phase Separated Polymer Using a Combined Atomic Force Microscopy/Infrared Spectroscopy/Mass Spectrometry Platform.

    PubMed

    Tai, Tamin; Karácsony, Orsolya; Bocharova, Vera; Van Berkel, Gary J; Kertesz, Vilmos

    2016-03-01

    In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry. The infrared chemical imaging component of the system utilized photothermal expansion of the sample at the tip of the atomic force microscopy probe recorded at infrared wave numbers specific to the different surface constituents. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for thermolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. The basic instrumental setup, operation, and image correlation procedures are discussed, and the multimodal imaging capability and utility are demonstrated using a phase separated poly(2-vinylpyridine)/poly(methyl methacrylate) polymer thin film. The topography and both the infrared and mass spectral chemical images showed that the valley regions of the thin film surface were comprised primarily of poly(2-vinylpyridine) and hill or plateau regions were primarily poly(methyl methacrylate). The spatial resolution of the mass spectral chemical images was estimated to be 1.6 μm based on the ability to distinguish surface features in those images that were also observed in the topography and infrared images of the same surface. PMID:26890087

  14. Chemically modified polymeric resins for solid-phase extraction and group separation prior to analysis by liquid or gas chromatography

    SciTech Connect

    Schmidt, L.W.

    1993-07-01

    Polystyrene divinylbenzene was modified by acetyl, sulfonic acid, and quaternary ammonium groups. A resin functionalized with an acetyl group was impregnated in a PTFE membrane and used to extract and concentrate phenolic compounds from aqueous samples. The acetyl group created a surface easily wetted, making it an efficient adsorbent for polar compounds in water. The membrane stabilized the resin bed. Partially sulfonated high surface area resins are used to extract and group separate an aqueous mixture of neutral and basic organics; the bases are adsorbed electrostatically to the sulfonic acid groups, while the neutraons are adsorbed hydrophobically. A two-step elution is then used to separate the two fractions. A partially functionalized anion exchange resin is used to separate organic acids and phenols from neutrals in a similar way. Carboxylic acids are analyzed by HPLC and phenols by GC.

  15. Influence of chemical and physical forms of ambient air acids on airway doses

    SciTech Connect

    Larson, T.V.

    1989-02-01

    The effects of ambient relative humidity and particle size on acid deposition within the airways have been examined with a computer model. For H/sub 2/SO/sub 4/ particles initially at 90% relative humidity in ambient air that are inhaled via the nose or mouth, there is significant deposition of acid in the airways even in the presence of typical values of respiratory NH/sub 3/. When these same particles are found in a fog at 100.015% relative humidity, there is significant deposition of acid in the nasal region during nose breathing but insignificant deposition to the deep lung for either nose or mouth breathing. The factors governing the partitioning of labile acid gases in the gas and liquid phases prior to inhalation are also discussed.

  16. Ram-air sample collection device for a chemical warfare agent sensor

    DOEpatents

    Megerle, Clifford A.; Adkins, Douglas R.; Frye-Mason, Gregory C.

    2002-01-01

    In a surface acoustic wave sensor mounted within a body, the sensor having a surface acoustic wave array detector and a micro-fabricated sample preconcentrator exposed on a surface of the body, an apparatus for collecting air for the sensor, comprising a housing operatively arranged to mount atop the body, the housing including a multi-stage channel having an inlet and an outlet, the channel having a first stage having a first height and width proximate the inlet, a second stage having a second lower height and width proximate the micro-fabricated sample preconcentrator, a third stage having a still lower third height and width proximate the surface acoustic wave array detector, and a fourth stage having a fourth height and width proximate the outlet, where the fourth height and width are substantially the same as the first height and width.

  17. Separating chemical and excluded volume interactions of polyethylene glycols with native proteins: Comparison with PEG effects on DNA helix formation.

    PubMed

    Shkel, Irina A; Knowles, D B; Record, M Thomas

    2015-09-01

    Small and large PEGs greatly increase chemical potentials of globular proteins (μ2), thereby favoring precipitation, crystallization, and protein-protein interactions that reduce water-accessible protein surface and/or protein-PEG excluded volume. To determine individual contributions of PEG-protein chemical and excluded volume interactions to μ2 as functions of PEG molality m3 , we analyze published chemical potential increments μ23  = dμ2/dm3 quantifying unfavorable interactions of PEG (PEG200-PEG6000) with BSA and lysozyme. For both proteins, μ23 increases approximately linearly with the number of PEG residues (N3). A 1 molal increase in concentration of PEG -CH2 OCH2 - groups, for any chain-length PEG, increases μBSA by ∼2.7 kcal/mol and μlysozyme by ∼1.0 kcal/mol. These values are similar to predicted chemical interactions of PEG -CH2 OCH2 - groups with these protein components (BSA ∼3.3 kcal/mol, lysozyme ∼0.7 kcal/mol), dominated by unfavorable interactions with amide and carboxylate oxygens and counterions. While these chemical effects should be dominant for small PEGs, larger PEGS are expected to exhibit unfavorable excluded volume interactions and reduced chemical interactions because of shielding of PEG residues in PEG flexible coils. We deduce that these excluded volume and chemical shielding contributions largely compensate, explaining why the dependence of μ23 on N3 is similar for both small and large PEGs. PMID:25924886

  18. Indoor Air in Beauty Salons and Occupational Health Exposure of Cosmetologists to Chemical Substances

    PubMed Central

    Tsigonia, Alexandra; Lagoudi, Argyro; Chandrinou, Stavroula; Linos, Athena; Evlogias, Nikos; Alexopoulos, Evangelos C.

    2010-01-01

    The indoor environment in four beauty salons located in Athens (Greece) was examined in order to investigate the occupational health exposure of cosmetologists to various chemical products typically used in their work. Chemical substances chosen for investigation were volatile organic compounds (VOCs), formaldehyde, ozone and carbon dioxide. Total VOCs levels measured showed significant variation (100–1,450 μg m−3) depending on the products used and the number of treatments carried out, as well as ventilation. The main VOCs found in the salons were aromatics (toluene, xylene), esters and ketones (ethyl acetate, acetone, etc.) which are used as solvents in various beauty products; terpenes (pinene, limonene, camphor, menthenol) which have a particular odor and others like camphor which have specific properties. Ozone concentrations measured in all salons were quite low (0.1 and 13.3 μg m−3) and formaldehyde concentrations detected were lower than the detection limit of the method in all salons (<0.05 ppm). Carbon dioxide levels ranged between 402 and 1,268 ppm, depending on the number of people present in the salons during measurements and ventilation. Cosmetologists may be exposed to high concentrations of a mixture of volatile organic compounds although these levels could be decreased significantly by following certain practices such as good ventilation of the areas, closing the packages of the beauty products when not in use and finally selecting safer beauty products without strong odor. PMID:20195448

  19. The selective conversion of glutamic acid in amino acid mixtures using glutamate decarboxylase--a means of separating amino acids for synthesizing biobased chemicals.

    PubMed

    Teng, Yinglai; Scott, Elinor L; Sanders, Johan P M

    2014-01-01

    Amino acids (AAs) derived from hydrolysis of protein rest streams are interesting feedstocks for the chemical industry due to their functionality. However, separation of AAs is required before they can be used for further applications. Electrodialysis may be applied to separate AAs, but its efficiency is limited when separating AAs with similar isoelectric points. To aid the separation, specific conversion of an AA to a useful product with different charge behavior to the remaining compounds is desired. Here the separation of L-aspartic acid (Asp) and L-glutamic acid (Glu) was studied. L-Glutamate α-decarboxylase (GAD, Type I, EC 4.1.1.15) was applied to specifically convert Glu into γ-aminobutyric acid (GABA). GABA has a different charge behavior from Asp therefore allowing a potential separation by electrodialysis. Competitive inhibition and reduced operational stability caused by Asp could be eliminated by maintaining a sufficiently high concentration of Glu. Immobilization of GAD does not reduce the enzyme's initial activity. However, the operational stability was slightly reduced. An initial study on the reaction operating in a continuous mode was performed using a column reactor packed with immobilized GAD. As the reaction mixture was only passed once through the reactor, the conversion of Glu was lower than expected. To complete the conversion of Glu, the stream containing Asp and unreacted Glu might be recirculated back to the reactor after GABA has been removed. Overall, the reaction by GAD is specific to Glu and can be applied to aid the electrodialysis separation of Asp and Glu. PMID:24616376

  20. Optimized Chemical Separation and Measurement by TE TIMS Using Carburized Filaments for Uranium Isotope Ratio Measurements Applied to Plutonium Chronometry.

    PubMed

    Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Prohaska, Thomas

    2016-06-21

    An optimized method is described for U/Pu separation and subsequent measurement of the amount contents of uranium isotopes by total evaporation (TE) TIMS with a double filament setup combined with filament carburization for age determination of plutonium samples. The use of carburized filaments improved the signal behavior for total evaporation TIMS measurements of uranium. Elevated uranium ion formation by passive heating during rhenium signal optimization at the start of the total evaporation measurement procedure was found to be a result from byproducts of the separation procedure deposited on the filament. This was avoided using carburized filaments. Hence, loss of sample before the actual TE data acquisition was prevented, and automated measurement sequences could be accomplished. Furthermore, separation of residual plutonium in the separated uranium fraction was achieved directly on the filament by use of the carburized filaments. Although the analytical approach was originally tailored to achieve reliable results only for the (238)Pu/(234)U, (239)Pu/(235)U, and (240)Pu/(236)U chronometers, the optimization of the procedure additionally allowed the use of the (242)Pu/(238)U isotope amount ratio as a highly sensitive indicator for residual uranium present in the sample, which is not of radiogenic origin. The sample preparation method described in this article has been successfully applied for the age determination of CRM NBS 947 and other sulfate and oxide plutonium samples. PMID:27240571

  1. CVD mullite coatings in high-temperature, high-pressure air-H{sub 2}O[Chemical Vapor Deposition

    SciTech Connect

    Haynes, J.A.; Lance, M.J.; Cooley, K.M.; Ferber, M.K.; Lowden, R.A.; Stinton, D.P.

    2000-03-01

    Crystalline mullite was deposited by chemical vapor deposition (CVD) onto SiC/SiC composites overlaid with CVD SiC. Specimens were exposed to isothermal oxidation tests in high-pressure air +H{sub 2}O at 1,200 C. Unprotected CVD SiC formed silica scales with a dense amorphous inner layer and a thick, porous, outer layer of cristobalite. Thin coatings ({approximately}2{mu}m) of dense CVD mullite effectively suppressed the rapid oxidation of CVD SiC. No microstructural evidence of mullite volatility was observed under these temperature, pressure, and low-flow-rate conditions. Results of this preliminary study indicate that dense, crystalline, high-purity CVD mullite is stable and protective in low-velocity, high-pressure, moisture-containing environments.

  2. Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air.

    PubMed

    Urabe, Tatsuya; Takahashi, Kazuya; Kitagawa, Michiko; Sato, Takafumi; Kondo, Tomohide; Enomoto, Shuichi; Kidera, Masanori; Seto, Yasuo

    2014-01-01

    A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future. PMID:24211802

  3. Hydrophobically-associating cationic polymers as micro-bubble surface modifiers in dissolved air flotation for cyanobacteria cell separation.

    PubMed

    Yap, R K L; Whittaker, M; Diao, M; Stuetz, R M; Jefferson, B; Bulmus, V; Peirson, W L; Nguyen, A V; Henderson, R K

    2014-09-15

    Dissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective cell removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, cell removals in excess of 90% were obtained, reaching a maximum of 99% cell removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations. PMID:24934266

  4. Procedures manual for the recommended ARB (Air Resources Board) sized chemical sample method (cascade cyclones)

    SciTech Connect

    McCain, J.D.; Dawes, S.S.; Farthing, W.E.

    1986-05-01

    The report is Attachment No. 2 to the Final Report of ARB Contract A3-092-32 and provides a tutorial on the use of Cascade (Series) Cyclones to obtain size-fractionated particulate samples from industrial flue gases at stationary sources. The instrumentation and procedures described are designed to protect the purity of the collected samples so that post-test chemical analysis may be performed for organic and inorganic compounds, including instrumental analysis for trace elements. The instrumentation described collects bulk quantities for each of six size fractions over the range 10 to 0.4 micrometer diameter. The report describes the operating principles, calibration, and empirical modeling of small cyclone performance. It also discusses the preliminary calculations, operation, sample retrieval, and data analysis associated with the use of cyclones to obtain size-segregated samples and to measure particle-size distributions.

  5. Measurement error models in chemical mass balance analysis of air quality data

    NASA Astrophysics Data System (ADS)

    Christensen, William F.; Gunst, Richard F.

    The chemical mass balance (CMB) equations have been used to apportion observed pollutant concentrations to their various pollution sources. Typical analyses incorporate estimated pollution source profiles, estimated source profile error variances, and error variances associated with the ambient measurement process. Often the CMB model is fit to the data using an iteratively re-weighted least-squares algorithm to obtain the effective variance solution. We consider the chemical mass balance model within the framework of the statistical measurement error model (e.g., Fuller, W.A., Measurement Error Models, Wiley, NewYork, 1987), and we illustrate that the models assumed by each of the approaches to the CMB equations are in fact special cases of a general measurement error model. We compare alternative source contribution estimators with the commonly used effective variance estimator when standard assumptions are valid and when such assumptions are violated. Four approaches for source contribution estimation and inference are compared using computer simulation: weighted least squares (with standard errors adjusted for source profile error), the effective variance approach of Watson et al. (Atmos, Environ., 18, 1984, 1347), the Britt and Luecke (Technometrics, 15, 1973, 233) approach, and a method of moments approach given in Fuller (1987, p. 193). For the scenarios we consider, the simplistic weighted least-squares approach performs as well as the more widely used effective variance solution in most cases, and is slightly superior to the effective variance solution when source profile variability is large. The four estimation approaches are illustrated using real PM 2.5 data from Fresno and the conclusions drawn from the computer simulation are validated.

  6. Air pollutants effect on monoterpenes composition and foliar chemical parameters in Schinus areira L.

    PubMed

    Wannaz, E D; Zygadlo, J A; Pignata, M L

    2003-04-15

    Monoterpenes, pigments, lipid peroxidation products, sulfur and water content expressed as dry weight/fresh weight ratio were measured in leaves of Schinus areira L. collected in Mendoza, Argentina. The sampling sites showed different SO(2), NO(2) and PM(10) levels, which allowed setting out zones by mapping. Foliar chemical parameters in S. areira were analysed in relation to these zones. High hydroperoxy conjugated dienes (HPCD) and alpha-phellandrene content in foliar samples coming from areas with high SO(2) levels were measured. Principal component analysis (PCA) showed a positive association among SO(2), HPCD, malondialdehyde, sabinene and beta-pinene. In relation to NO(2) levels high values of chlorophyll (Chl)-b and Chl-b/Chl-a ratio were found. PCA showed for NO(2), an association with Chl-b/Chl-a, phaeophytin-a/Chl-a ratios and alpha-phellandrene. As regard PM(10), no significant differences were found in the chemical parameters indicating foliar damage, whereas the contents of tricyclene, alpha-pinene and beta-pinene showed low values in the area with high levels of this pollutant. From the results, it can be inferred that the more noticeable changes in the foliar chemistry of S. areira were detected in relation to the different SO(2) levels. This response was associated to an increase in the foliar oxidation processes accompanied by modifications in the levels of terpenes. This is important, as SO(2) was the only pollutant whose values in the annual arithmetic mean were over the standard value of 30 ppb. PMID:12670767

  7. Sensitive monitoring of volatile chemical warfare agents in air by atmospheric pressure chemical ionization mass spectrometry with counter-flow introduction.

    PubMed

    Seto, Yasuo; Kanamori-Kataoka, Mieko; Tsuge, Koichiro; Ohsawa, Isaac; Iura, Kazumitsu; Itoi, Teruo; Sekiguchi, Hiroyuki; Matsushita, Koji; Yamashiro, Shigeharu; Sano, Yasuhiro; Sekiguchi, Hiroshi; Maruko, Hisashi; Takayama, Yasuo; Sekioka, Ryoji; Okumura, Akihiko; Takada, Yasuaki; Nagano, Hisashi; Waki, Izumi; Ezawa, Naoya; Tanimoto, Hiroyuki; Honjo, Shigeru; Fukano, Masumi; Okada, Hidehiro

    2013-03-01

    A new method for sensitively and selectively detecting chemical warfare agents (CWAs) in air was developed using counter-flow introduction atmospheric pressure chemical ionization mass spectrometry (MS). Four volatile and highly toxic CWAs were examined, including the nerve gases sarin and tabun, and the blister agents mustard gas (HD) and Lewisite 1 (L1). Soft ionization was performed using corona discharge to form reactant ions, and the ions were sent in the direction opposite to the airflow by an electric field to eliminate the interfering neutral molecules such as ozone and nitrogen oxide. This resulted in efficient ionization of the target CWAs, especially in the negative ionization mode. Quadrupole MS (QMS) and ion trap tandem MS (ITMS) instruments were developed and investigated, which were movable on the building floor. For sarin, tabun, and HD, the protonated molecular ions and their fragment ions were observed in the positive ion mode. For L1, the chloride adduct ions of L1 hydrolysis products were observed in negative ion mode. The limit of detection (LOD) values in real-time or for a 1 s measurement monitoring the characteristic ions were between 1 and 8 μg/m(3) in QMS instrument. Collision-induced fragmentation patterns for the CWAs were observed in an ITMS instrument, and optimized combinations of the parent and daughter ion pairs were selected to achieve real-time detection with LOD values of around 1 μg/m(3). This is a first demonstration of sensitive and specific real-time detection of both positively and negatively ionizable CWAs by MS instruments used for field monitoring. PMID:23339735

  8. Effect of the chemical heat treatment in a semianthracite char on the textural properties and the gasification in air

    SciTech Connect

    Dominguez, M.A.

    2009-08-15

    The effects of the chemical heat treatments of a semianthracite char (AC) on the textural properties and the gasification in air are investigated. Sample AC first was treated with the LiCl/KCl mixture or the mixture formed by LiCl/IKCl and a metallic oxide, M{sub n=1,2}O (MgO, CaO, FeO, CoO, NiO, Cu{sub 2}O or ZnO) at 743, 873 or 1173 K and products obtained they were then washed carefully with water distilled. The information on the textural modifications was deduced of isotherms of CO{sub 2} adsorption to 273 K. The reactivity tests were taken to the temperature 808, 823 and 838 K. As resulting from the AC treatments, on developed the microporosity and on increase the air reactivity, in particular, the first effect is greater when the used mixture went LiCl/KCl/CoO at 1173 K and the second effect are greater when the used mixture went LiCl/KCl/Cu{sub 2}O at 1173 K.

  9. Large scale air pollution estimation method combining land use regression and chemical transport modeling in a geostatistical framework.

    PubMed

    Akita, Yasuyuki; Baldasano, Jose M; Beelen, Rob; Cirach, Marta; de Hoogh, Kees; Hoek, Gerard; Nieuwenhuijsen, Mark; Serre, Marc L; de Nazelle, Audrey

    2014-04-15

    In recognition that intraurban exposure gradients may be as large as between-city variations, recent air pollution epidemiologic studies have become increasingly interested in capturing within-city exposure gradients. In addition, because of the rapidly accumulating health data, recent studies also need to handle large study populations distributed over large geographic domains. Even though several modeling approaches have been introduced, a consistent modeling framework capturing within-city exposure variability and applicable to large geographic domains is still missing. To address these needs, we proposed a modeling framework based on the Bayesian Maximum Entropy method that integrates monitoring data and outputs from existing air quality models based on Land Use Regression (LUR) and Chemical Transport Models (CTM). The framework was applied to estimate the yearly average NO2 concentrations over the region of Catalunya in Spain. By jointly accounting for the global scale variability in the concentration from the output of CTM and the intraurban scale variability through LUR model output, the proposed framework outperformed more conventional approaches. PMID:24621302

  10. Wet air oxidation for the treatment of industrial wastes. Chemical aspects, reactor design and industrial applications in Europe

    SciTech Connect

    Debellefontaine, H.; Foussard, J.N.

    2000-07-01

    Aqueous wastes containing organic pollutants can be efficiently treated by wet air oxidation (WAO), i.e., oxidation (or combustion) by molecular oxygen in the liquid phase, at high temperature (200--325 C) and pressure (up to 175 bar). This method is suited to the elimination of special aqueous wastes from the chemical industry as well as to the treatment of domestic sludge. It is an enclosed process, with a limited interaction with the environment, as opposed to incineration. Usually, the operating cost is lower than 95 Euro M{sup {minus}3} and the preferred COD load ranges from 10 to 80 kg m{sup {minus}3}. Only a handful of industrial reactors are in operation world-wide, mainly because of the high capital investment they require. This paper reviews the major results obtained with the WAO process and assess its field of possible application to industrial wastes. In addition, as only a very few studies have been devoted to the scientific design of such reactors (bubble columns), what needs to be known for this scientific design is discussed. At present, a computer program aimed at determining the performance of a wet air oxidation reactor depending on the various operating parameters has been implemented at the laboratory. Some typical results are presented, pointing out the most important parameters and the specific behavior of these units.

  11. Concentrations and changes of chemical elements in aerosol particulate matter as indicators of air quality in Riyadh City, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Rushdi, A. I.; Al-Mutlaq, K. F.; Simoneit, B. R.

    2010-12-01

    : Samples of air particulate matter (PM) were collected for the determination of chemical elements from June 2006 to May 2007. PM samples were taken in two size modes (PM2.5 and PM10) using MiniVolume air samplers on rooftops of various buildings (15-25 m above ground) in the city of Riyadh. The samples were subjected to XRF analysis to determine both major (Na, Mg, Al, K, Ca, Si, P, S and Fe) and trace elements (Mn, Ni, Cu, Zn, and Ba). The results show that the concentrations of both were higher in PM10 compared to PM2.5 indicating that the major source of the atmospheric PM was local dust. Furthermore, the spatial distribution of high concentrations of PM was in the south and southeast of the city and the lowest was found in the center and north eastern part of the city. This spatial PM distribution was attributed different factors such as wind direction and velocity, existence of cement factories in the southeast of the city, the presence of buildings and trees, and paved streets in the city center that reduce the amount of dust resuspended into the atmosphere. The air quality of the city was found to range from moderate to highly unhealthy for PM2.5 and from good to highly unhealthy for PM10. The enrichment factors for the measured elements were examined and revealed two groups based on their regional distribution. The first group showed no significant spatial changes indicating it has a common source throughout the sampling grid. The second group (mainly S and Ni) showed significant changes as expected from anthropogenic inputs. The S is possibly a combination of a mineralogical (CaSO4) and fossil fuel combustion origin. The source of Ni is probably in emissions from fossil fuel combustion.

  12. Discrimination and chemical characterization of different Paeonia lactifloras (Radix Paeoniae Alba and Radix Paeoniae Rubra) by infrared macro-fingerprint analysis-through-separation

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Wang, Ping; Xu, Changhua; Sun, Suqin; Zhou, Qun; Shi, Zhe; Li, Jin; Chen, Tao; Li, Zheng; Cui, Weili

    2015-11-01

    Paeonia lactiflora, a commonly used herbal medicine (HM) in Traditional Chinese Medicine (TCM), mainly has two species, Radix Paeoniae Alba (RPA) and Radix Paeoniae Rubra (RPR), for different clinical applications in TCM. For expounding the chemical profile of RPA and RPR and ensuring the clinical efficacy and safety, an infrared macro-fingerprint analysis-through-separation method integrated with statistical pattern recognition was developed to analyze and discriminate the two Paeonia lactifloras. In IR spectra, the major difference between the two was in the range of 1200-900 cm-1: the strongest peak of RPA was at 1024 cm-1, while that of RPR was 1049 cm-1. The difference was magnified in second derivative spectra. The findings were further verified by investigating the separation process of total glucosides, stepwisely monitored by both of IR and UPLC-MS/MS. Simultaneously, the aqueous extracts of RPA and RPR had been separated continuously to acquire the comprehensively hierarchical chemical characteristics for undoubtedly identification and subsequently discrimination of the two herbs. Moreover, 60 batches of the two HMs (30 for each) were objectively classified by principal component regression (PCR) model based on IR macro-fingerprints.

  13. A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.

    1989-01-01

    Reaction rate coefficients and thermodynamic and transport properties are provided for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in such environments.

  14. Synoptic Mapping of Chemical Composition, Thermal Structure, and Air Motion from UARS Observations

    NASA Technical Reports Server (NTRS)

    Salby, Murry L.

    1999-01-01

    An operational mapping algorithm was developed to process measurements of individual species observed by different satellite instruments on board UARS. Based on Fast Fourier Synoptic Mapping (FFSM), the algorithm accounts for the precessing orbit of UARS, the error of individual instruments, and gaps associated with instrument duty cycle and the satellite yaw maneuver. It provides synoptic structure and evolution on periods as short as 1 day, derived collectively from all observations of an individual species. The algorithm was applied to synoptically map temperature, thickness, and several chemical constituents observed by the instruments: MLS, CLAES, ISAMS, and HALOE. Each field variable observed by these instruments was mapped twice-daily in continuous global time series several months long. Mapped behavior produced via FFSM was compared against standard archived products generated via Kalman filtering. The standard map products reveal similar behavior, but are limited to features of larger scale. Tracer structure that develops through flow deformation and attending transport is therefore represented in those products more coarsely, eventually being sheared down to scales that are no longer represented properly. The synoptic time series also reveal a diurnal cycle for several of the constituents, one that emerges clearly in their space-time spectra. The zonal and meridional structure of diurnal variability was mapped by filtering the space-time spectrum, an intermediate product of FFSM, to those scales resolved by the UARS sampling. Geographical variations of the diurnal cycle have also been evaluated in its seasonal-mean structure by compositing distributions at individual local times. Both were compared to diurnal variations in chemical models and in dynamical models that account for transport by the diurnal tide. Diurnal variations were found to introduce spurious behavior into the archived products generated via Kalman filtering, behavior that is

  15. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rate

    SciTech Connect

    Chuang, J.; Cao, S.; Xian, Y.; Harris, B.; Mumford, J.

    1992-01-01

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions. Homes using different fuels from communes with high and low lung cancer mortality rates were sampled for particulate matter (<10 micrometers) and semivolatile organics. The fine particles obtained from homes using smoky coal contained highest concentrations of organic matter (> 70%), including PAH, followed by homes using wood and smokeless coal. The major components present in the smoky coal filter samples were PAH and alkylated PAH. The smokeless coal filter samples exhibited profiles which were similar to the smoky coal samples except that some sulfur compounds were found. The estimated concentration levels of PAH in the smokeless coal samples were about one to two orders of magnitude lower than those of the smoky coal samples. In addition to PAH, aliphatic compounds and fatty acids were the major components found in the wood samples. Selected sample extracts from homes using smoky coal were fractionated into four fractions, and the results showed that the PAH and polar fractions have high mutagenic activity. Chemical characterization of the PAH fraction indicated that concentrations of some alkylated PAH were higher than those of their parent compounds. Chemical characterization of the polar fractions showed that nitrogen heterocyclic compounds are present.

  16. Comparing three vegetation monoterpene emission models to measured gas concentrations with a model of meteorology, air chemistry and chemical transport

    NASA Astrophysics Data System (ADS)

    Smolander, S.; He, Q.; Mogensen, D.; Zhou, L.; Bäck, J.; Ruuskanen, T.; Noe, S.; Guenther, A.; Aaltonen, H.; Kulmala, M.; Boy, M.

    2013-11-01

    Biogenic volatile organic compounds (BVOCs) are essential in atmospheric chemistry because of their chemical reactions that produce and destroy tropospheric ozone, their effects on aerosol formation and growth, and their potential influence on global warming. As one of the important BVOC groups, monoterpenes have been a focus of scientific attention in atmospheric research. Detailed regional measurements and model estimates are needed to study emission potential and the monoterpene budget on a global scale. Since the use of empirical measurements for upscaling is limited by many physical and biological factors such as genetic variation, temperature and light, water availability, seasonal changes, and environmental stresses, comprehensive inventories over larger areas are difficult to obtain. We applied the boundary layer-chemistry-transport model SOSA to investigate Scots pine (Pinus sylvestris) monoterpene emissions in a boreal coniferous forest at the SMEAR II site, Southern Finland. SOSA was applied to simulate monoterpene emissions with three different emission modules: the semi-empirical G95, MEGAN 2.04 with improved descriptions of temperature and light responses and including also carbonyl emissions, and a process-based model SIM-BIM. For the first time, the emission models included seasonal and diurnal variations in both quantity and chemical species of emitted monoterpenes, based on parameterizations obtained from field measurements. Results indicate that modelling and observations agreed reasonably well, and that the model can be used for investigating regional air chemistry questions related to monoterpenes. The predominant modelled monoterpene concentrations, α-pinene and Δ3-carene, are consistent with observations.

  17. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rate

    NASA Astrophysics Data System (ADS)

    Chuang, J. C.; Cao, S. R.; Xian, Y. L.; Harris, D. B.; Mumford, J. L.

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions. Homes using different fuels from communes with high and low lung cancer mortality rates were sampled for particulate matter (< 10 μm) and semivolatile organics. The fine particles obtained from homes using smoky coal contained highest concentrations of organic matter (> 70%), including PAH, followed by homes using wood and smokeless coal. The major components present in the smoky coal filter samples were PAH and alkylated PAH. The smokeless coal filter samples exhibited profiles which were similar to the smoky coal samples except that some sulfur compounds were found. The estimated concentration levels of PAH in the smokeless coal samples were about one to two orders of magnitude lower than those of the smoky coal samples. In addition to PAH, aliphatic compounds and fatty acids were the major components found in the wood samples. Selected sample extracts from homes using smoky coal were fractionated into four fractions, and the results showed that the PAH and polar fractions have high mutagenic activity. Chemical characterization of the PAH fraction indicated that concentrations of some alkylated PAH were higher than those of their parent compounds. Chemical characterization of the polar fractions showed that nitrogen heterocyclic compounds are present.

  18. Volatile organic chemical emissions from structural insulated panel (SIP) materials and implications for indoor air quality

    SciTech Connect

    Hodgson, Alfred T.

    2003-09-01

    The emissions of volatile organic compounds (VOCs) from structural insulated panel (SIP) materials were investigated. Specimens of newly produced SIPs and associated panel adhesives were obtained from two relatively large manufacturers. Additionally, specimens of the oriented strand board (OSB) used as the inner and outer sheathing and the extruded polystyrene core for the SIP were obtained from one manufacturer. Using small-scale chambers, emissions of formaldehyde, acetaldehyde, acetic acid and other VOCs from SIPs, OSB and polystyrene were measured over a period of four months and from the adhesives over two months. SIP specimens overlaid by gypsum board panels were also tested over four months. The predominant VOCs emitted by the SIPs included acetic acid, pentanal, hexanal and styrene. The emissions of formaldehyde and acetaldehyde were relatively low. Acetic acid and the aldehydes derived from the OSB, while styrene derived from the polystyrene. One of the SIPs emitted toluene and methyl acetate. The adhesives primarily emitted a mixture of hydrocarbons. The emission rates of most VOCs from the SIP/gypsum board assemblies were approximately the same or higher than their respective emission rates from the unfinished SIPs. Modeling using VOC emission factors obtained for the SIP/gypsum board assemblies demonstrated the potential for SIP materials to degrade indoor air quality in houses. A field study to investigate VOC concentrations and emission rates in SIP houses relative to closely matched conventionally constructed houses is necessary to determine the actual impacts of SIPs. If significant impacts are observed, to it may be desirable to develop control measures to reduce the emissions of VOCs from SIPs, such as the substitution of lower emitting materials or the use of vapor diffusion barriers.

  19. Stereoisomers Separation

    NASA Astrophysics Data System (ADS)

    Wieczorek, Piotr

    The use of capillary electrophoresis for enantiomer separation and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be separated show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the separation based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers separation and determination are presented.

  20. A review of induction and attachment times of wetting thin films between air bubbles and particles and its relevance in the separation of particles by flotation.

    PubMed

    Albijanic, Boris; Ozdemir, Orhan; Nguyen, Anh V; Bradshaw, Dee

    2010-08-11

    Bubble-particle attachment in water is critical to the separation of particles by flotation which is widely used in the recovery of valuable minerals, the deinking of wastepaper, the water treatment and the oil recovery from tar sands. It involves the thinning and rupture of wetting thin films, and the expansion and relaxation of the gas-liquid-solid contact lines. The time scale of the first two processes is referred to as the induction time, whereas the time scale of the attachment involving all the processes is called the attachment time. This paper reviews the experimental studies into the induction and attachment times between minerals and air bubbles, and between oil droplets and air bubbles. It also focuses on the experimental investigations and mathematical modelling of elementary processes of the wetting film thinning and rupture, and the three-phase contact line expansion relevant to flotation. It was confirmed that the time parameters, obtained by various authors, are sensitive enough to show changes in both flotation surface chemistry and physical properties of solid surfaces of pure minerals. These findings should be extended to other systems. It is proposed that measurements of the bubble-particle attachment can be used to interpret changes in flotation behaviour or, in conjunction with other factors, such as particle size and gas dispersion, to predict flotation performance. PMID:20478547

  1. Open-air type plasma chemical vaporization machining by applying pulse-width modulation control

    NASA Astrophysics Data System (ADS)

    Takeda, Yoshiki; Hata, Yuki; Endo, Katsuyoshi; Yamamura, Kazuya

    2014-03-01

    Photolithography techniques have been used to enable the low-cost and high-speed transfer of a pattern onto a silicon wafer. However, owing to the high integration of semiconductors, extreme ultraviolet will be increasingly used as the exposure light source and all optics must be reflective to focus light because the wavelength of the light will be so short that it cannot pass through a lens. The form accuracy of reflective optics affects the accuracy of transfer, and a flatness of less than 32 nm on a 6 inch photomask substrate is required according to the International Technology Roadmap for Semiconductors roadmap. Plasma chemical vaporization machining is an ultraprecise figuring technique that enables a form accuracy of nanometre order to be obtained. In our previous study, the removal volume was controlled by changing the scanning speed of the worktable. However, a discrepancy between the theoretical scanning speed and the actual scanning speed occurred owing to the inertia of the worktable when the change in speed was rapid. As an attempt to resolve this issue, we controlled the removal volume by controlling the electric power applied during plasma generation while maintaining a constant scanning speed. The methods that we adapted to control the applied electric power were amplitude-modulation (AM) control and pulse-width modulation (PWM) control. In this work, we evaluate the controllability of the material removal rate in the AM and PWM control modes.

  2. Risk-based objectives for the allocation of chemical, biological, and radiological air emissions sensors.

    PubMed

    Lambert, James H; Farrington, Mark W

    2006-12-01

    This article addresses the problem of allocating devices for localized hazard protection across a region. Each identical device provides only local protection, and the devices serve localities that are exposed to nonidentical intensities of hazard. A method for seeking the optimal allocation Policy Decisions is described, highlighting the potentially competing objectives of maximizing local risk reductions and coverage risk reductions. The metric for local risk reductions is the sum of the local economic risks avoided. The metric for coverage risk reductions is adapted from the p-median problem and equal to the sum of squares of the distances from all unserved localities to their closest associated served locality. Three graphical techniques for interpreting the Policy Decisions are presented. The three linked graphical techniques are applied serially. The first technique identifies Policy Decisions that are nearly Pareto optimal. The second identifies locations where sensor placements are most justified, based on a risk-cost-benefit analysis under uncertainty. The third displays the decision space for any particular policy decision. The method is illustrated in an application to chemical, biological, and/or radiological weapon sensor placement, but has implications for disaster preparedness, transportation safety, and other arenas of public safety. PMID:17184404

  3. Micro-channels in the mastoid anatomy. Indications of a separate blood supply of the air cell system mucosa by micro-CT scanning.

    PubMed

    Cros, Olivier; Borga, Magnus; Pauwels, Elin; Dirckx, Joris J J; Gaihede, Michael

    2013-07-01

    The mastoid air cell system has traditionally been considered to have a passive role in gas exchange and pressure regulation of the middle ear possibly with some acoustic function. However, more evidence has focused on the mucosa of the mastoid, which may play a more active role in regulation of middle ear pressure. In this study we have applied micro-CT scanning on a series of three human temporal bones. This approach greatly enhances the resolution (40-60 μm), so that we have discovered anatomical details, which has not been reported earlier. Thus, qualitative analysis using volume rendering has demonstrated notable micro-channels connecting the surface of the compact bone directly to the mastoid air cells as well as forming a network of connections between the air cells. Quantitative analysis on 2D slices was employed to determine the average diameter of these micro-channels (158 μm; range = 40-440 μm) as well as their density at a localized area (average = 75 cm(-2); range = 64-97 cm(-2)). These channels are hypothesized to contain a separate vascular supply for the mastoid mucosa. However, future studies of the histological structure of the micro-channels are warranted to confirm the hypothesis. Studies on the mastoid mucosa and its blood supply may improve our knowledge of its physiological properties, which may have important implications for our understanding of the pressure regulation of the middle ear. This article is part of a special issue entitled "MEMRO 2012". PMID:23518400

  4. Controlling Solution Self-assembly and Non-Solvent Induced Microphase Separation of Triblock Terpolymers to Generate Nanofiltration Membranes with Chemically-Tailored Pore Walls

    NASA Astrophysics Data System (ADS)

    Boudouris, Bryan; Mulvenna, Ryan; Weidman, Jacob; Phillip, William

    2014-03-01

    Block polymer-based templates have been utilized in a number of membrane applications; however, there has yet to be a demonstration of a nanoporous block polymer thin film that can achieve high flux and high selectivity simultaneously while also allowing for the facile tuning of the pore wall chemistry. Here, we demonstrate that by synthesizing and controlling the solution self-assembly of a triblock terpolymer, polyisoprene- b-polystyrene- b-poly(N, N-dimethylacrylamide) (PI-PS-PDMA), and precisely inducing non-solvent induced phase separation during the self-assembly process allows for the creation of an asymmetric nanoporous membrane with PDMA-lined pore walls. This PDMA functionality is then converted to any number of side chain functionalities through simple chemistry in the solid state. In this way, we are able to show a highly selectivity membrane that can separate analytes of interest based both on size and chemical composition at a high solution flux. In fact, this high fidelity structure has a very narrow distribution of pore sizes (<10% variation in diameter) over large areas (>500 cm2) . This has allowed for the separation of particles with hydrodynamic radii as low as 0.8 nm, which is the smallest separation achieved using a block polymer-based membrane to date.

  5. Initiated Chemical Vapor Deposition (iCVD) of Highly Cross-Linked Polymer Films for Advanced Lithium-Ion Battery Separators.

    PubMed

    Yoo, Youngmin; Kim, Byung Gon; Pak, Kwanyong; Han, Sung Jae; Song, Heon-Sik; Choi, Jang Wook; Im, Sung Gap

    2015-08-26

    We report an initiated chemical vapor deposition (iCVD) process to coat polyethylene (PE) separators in Li-ion batteries with a highly cross-linked, mechanically strong polymer, namely, polyhexavinyldisiloxane (pHVDS). The highly cross-linked but ultrathin pHVDS films can only be obtained by a vapor-phase process, because the pHVDS is insoluble in most solvents and thus infeasible with conventional solution-based methods. Moreover, even after the pHVDS coating, the initial porous structure of the separator is well preserved owing to the conformal vapor-phase deposition. The coating thickness is delicately controlled by deposition time to the level that the pore size decreases to below 7% compared to the original dimension. The pHVDS-coated PE shows substantially improved thermal stability and electrolyte wettability. After incubation at 140 °C for 30 min, the pHVDS-coated PE causes only a 12% areal shrinkage (versus 90% of the pristine separator). The superior wettability results in increased electrolyte uptake and ionic conductivity, leading to significantly improved rate performance. The current approach is applicable to a wide range of porous polymeric separators that suffer from thermal shrinkage and poor electrolyte wetting. PMID:26258806

  6. Predicting paramagnetic 1H NMR chemical shifts and state-energy separations in spin-crossover host-guest systems.

    PubMed

    Isley, William C; Zarra, Salvatore; Carlson, Rebecca K; Bilbeisi, Rana A; Ronson, Tanya K; Nitschke, Jonathan R; Gagliardi, Laura; Cramer, Christopher J

    2014-06-14

    The behaviour of metal-organic cages upon guest encapsulation can be difficult to elucidate in solution. Paramagnetic metal centres introduce additional dispersion of signals that is useful for characterisation of host-guest complexes in solution using nuclear magnetic resonance (NMR). However, paramagnetic centres also complicate spectral assignment due to line broadening, signal integration error, and large changes in chemical shifts, which can be difficult to assign even for known compounds. Quantum chemical predictions can provide information that greatly facilitates the assignment of NMR signals and identification of species present. Here we explore how the prediction of paramagnetic NMR spectra may be used to gain insight into the spin crossover (SCO) properties of iron(II)-based metal organic coordination cages, specifically examining how the structure of the local metal coordination environment affects SCO. To represent the tetrahedral metal-organic cage, a model system is generated by considering an isolated metal-ion vertex: fac-ML3(2+) (M = Fe(II), Co(II); L = N-phenyl-2-pyridinaldimine). The sensitivity of the (1)H paramagnetic chemical shifts to local coordination environments is assessed and utilised to shed light on spin crossover behaviour in iron complexes. Our data indicate that expansion of the metal coordination sphere must precede any thermal SCO. An attempt to correlate experimental enthalpies of SCO with static properties of bound guests shows that no simple relationship exists, and that effects are likely due to nuanced dynamic response to encapsulation. PMID:24752730

  7. Characterization of Cerro Negro crude. Part I. Physical and chemical separations. [Project shared by Bartlesville Energy Technology Center, US DOE, and Institute de Tecnologico del Venezolana Petroleo

    SciTech Connect

    Grizzle, P.L.; Green, J.B.; Sanchez, V.; Murgia, E.; Lubkowitz, J.

    1981-09-01

    The scheme couples distillation and ion exchange and solid liquid chromatography in an attempt to prepare narrow-boiling, chemically unique fractions, which can be analyzed further or can supply data for process development. For evaluation of the separation approach, a Cerro Negro crude from the Venezuelan Orinoco basin has been studied in a cooperative program between the United States Department of Energy and the Institute de Tecnologico del Venezolana Petroleo. These fractions may be analyzed by ir, uv, fluorescence, and nuclear magnetic resonance spectroscopy, as well as various mass spectroscopy methods. The approach appears to be promising. 5 figures, 6 tables.

  8. Multiple acquisition/multiple observation separated local field/chemical shift correlation solid-state magic angle spinning NMR spectroscopy.

    PubMed

    Das, Bibhuti B; Opella, Stanley J

    2014-08-01

    Multiple acquisition spectroscopy (MACSY) experiments that enable multiple free induction decays to be recorded during individual experiments are demonstrated. In particular, the experiments incorporate separated local field spectroscopy into homonuclear and heteronuclear correlation spectroscopy. The measured heteronuclear dipolar couplings are valuable in structure determination as well as in enhancing resolution by providing an additional frequency axis. In one example four different three-dimensional spectra are obtained in a single experiment, demonstrating that substantial potential saving in experimental time is available when multiple multi-dimensional spectra are required as part of solid-state NMR studies. PMID:25023566

  9. Multiple Acquisition/Multiple Observation Separated Local Field/Chemical Shift Correlation Solid-state Magic Angle Spinning NMR Spectroscopy

    PubMed Central

    Das, Bibhuti B.; Opella, Stanley J.

    2014-01-01

    Multiple acquisition spectroscopy (MACSY) experiments that enable multiple free induction decays to be recorded during individual experiments are demonstrated. In particular, the experiments incorporate separated local field spectroscopy into homonuclear and heteronuclear correlation spectroscopy. The measured heteronuclear dipolar couplings are valuable in structure determination as well as in enhancing resolution by providing an additional frequency axis. In one example four different three-dimensional spectra are obtained in a single experiment, demonstrating that substantial potential saving in experimental time is available when multiple multi-dimensional spectra are required as part of solid-state NMR studies. PMID:25023566

  10. Chemical composition of individual aerosol particles in workplace air during production of manganese alloys.

    PubMed

    Gunst, S; Weinbruch, S; Wentzel, M; Ortner, H M; Skogstad, A; Hetland, S; Thomassen, Y

    2000-02-01

    Aerosol particle samples were collected at ELKEM ASA ferromanganese (FeMn) and silicomanganese (SiMn) smelters at Porsgrunn, Norway, during different production steps: raw material mixing, welding of protective steel casings, tapping of FeMn and slag, crane operation moving the ladles with molten metal, operation of the Metal Oxygen Refinement (MOR) reactor and casting of SiMn. Aerosol fractions were assessed for the analysis of the bulk elemental composition as well as for individual particle analysis. The bulk elemental composition was determined by inductively coupled plasma atomic emission spectrometry. For individual particle analysis, an electron microprobe was used in combination with wavelength-dispersive techniques. Most particles show a complex composition and cannot be attributed to a single phase. Therefore, the particles were divided into six groups according to their chemical composition: Group I, particles containing mainly metallic Fe and/or Mn; Group II, slag particles containing mainly Fe and/or Mn oxides; Group III, slag particles consisting predominantly of oxidized flux components such as Si, Al, Mg, Ca, Na and K; Group IV, particles consisting mainly of carbon; Group V, mixtures of particles from Groups II, III and IV; Group VI, mixtures of particles from Groups II and III. In raw material mixing, particles originating from the Mn ores were mostly found. In the welding of steel casings, most particles were assigned to Group II, Mn and Fe oxides. During the tapping of slag and metal, mostly slag particles from Group III were found (oxides of the flux components). During movement of the ladles, most particles came from Group II. At the MOR reactor, most of the particles belonged to the slag phase consisting of the flux components (Group III). The particles collected during the casting of SiMn were mainly attributed to the slag phase (Groups III and V). Due to the compositional complexity of the particles, toxicological investigations on the

  11. Assessment of the ability of amphibious assault ship (LHA class) to perform sustained air operations in a chemical environment. Final report

    SciTech Connect

    Henry, B.C.; Laughlin, L.L.

    1988-03-10

    This report describes how an attack with chemical warfare agents would affect air operations on an LHA operating in support of an amphibious assault. This report overlays a chemical attack on normal flight deck operational sequences and describes in detail how having to operate in a chemically contaminated environment affects the sortie rate of troop airlift (CH-46 and CH-53 helicopters) and close air support (AH-1T) a their specific tasks while wearing the chemical protective overgarment, protective overboots and gloves. b. All the chemical defense equipment required by existing Navy directives is available and has been issued for use; c. Additional personnel required to conduct flight operations in a chemical environment are available and cross trained to perform tasks assigned in this study; d. There are no accidents, incidents, aircraft losses or battle damage which affect the tempo of flight deck operations; e. After four hours, the chemical contamination has been reduced sufficiently by weathering that flight deck personnel were able to reduce their protective posture to Mask Only. The report describes a series of recommendations to improve overall flight deck operations in a chemical environment.

  12. Air-gating and chemical-gating in transistors and sensing devices made from hollow TiO2 semiconductor nanotubes

    NASA Astrophysics Data System (ADS)

    Alivov, Yahya; Funke, Hans; Nagpal, Prashant

    2015-07-01

    Rapid miniaturization of electronic devices down to the nanoscale, according to Moore’s law, has led to some undesirable effects like high leakage current in transistors, which can offset additional benefits from scaling down. Development of three-dimensional transistors, by spatial extension in the third dimension, has allowed higher contact area with a gate electrode and better control over conductivity in the semiconductor channel. However, these devices do not utilize the large surface area and interfaces for new electronic functionality. Here, we demonstrate air gating and chemical gating in hollow semiconductor nanotube devices and highlight the potential for development of novel transistors that can be modulated using channel bias, gate voltage, chemical composition, and concentration. Using chemical gating, we reversibly altered the conductivity of nanoscaled semiconductor nanotubes (10-500 nm TiO2 nanotubes) by six orders of magnitude, with a tunable rectification factor (ON/OFF ratio) ranging from 1-106. While demonstrated air- and chemical-gating speeds were slow here (˜seconds) due to the mechanical-evacuation rate and size of our chamber, the small nanoscale volume of these hollow semiconductors can enable much higher switching speeds, limited by the rate of adsorption/desorption of molecules at semiconductor interfaces. These chemical-gating effects are completely reversible, additive between different chemical compositions, and can enable semiconductor nanoelectronic devices for ‘chemical transistors’, ‘chemical diodes’, and very high-efficiency sensing applications.

  13. Air-gating and chemical-gating in transistors and sensing devices made from hollow TiO2 semiconductor nanotubes.

    PubMed

    Alivov, Yahya; Funke, Hans; Nagpal, Prashant

    2015-07-24

    Rapid miniaturization of electronic devices down to the nanoscale, according to Moore's law, has led to some undesirable effects like high leakage current in transistors, which can offset additional benefits from scaling down. Development of three-dimensional transistors, by spatial extension in the third dimension, has allowed higher contact area with a gate electrode and better control over conductivity in the semiconductor channel. However, these devices do not utilize the large surface area and interfaces for new electronic functionality. Here, we demonstrate air gating and chemical gating in hollow semiconductor nanotube devices and highlight the potential for development of novel transistors that can be modulated using channel bias, gate voltage, chemical composition, and concentration. Using chemical gating, we reversibly altered the conductivity of nanoscaled semiconductor nanotubes (10-500 nm TiO2 nanotubes) by six orders of magnitude, with a tunable rectification factor (ON/OFF ratio) ranging from 1-10(6). While demonstrated air- and chemical-gating speeds were slow here (∼seconds) due to the mechanical-evacuation rate and size of our chamber, the small nanoscale volume of these hollow semiconductors can enable much higher switching speeds, limited by the rate of adsorption/desorption of molecules at semiconductor interfaces. These chemical-gating effects are completely reversible, additive between different chemical compositions, and can enable semiconductor nanoelectronic devices for 'chemical transistors', 'chemical diodes', and very high-efficiency sensing applications. PMID:26134618

  14. Chemical enrichment and separation of uranyl ions in aqueous media using novel polyurethane foam chemically grafted with different basic dyestuff sorbents.

    PubMed

    El-Shahat, M F; Moawed, E A; Farag, A B

    2007-01-15

    The new type of the grafted polyurethane foam sorbents were prepared by coupling polyether polyol, toluene diisocyanate and basic dyestuff (Methylene blue, Rhodamine B and Brilliant green). The Me.B-PUF, Rh.B-PUF and Br.G-PUF were characterized using UV/vis, IR and TGA. The adsorption properties and chromatographic behaviour of these new adsorbents for preconcentration and separation of uranium(VI) ions at low concentrations from aqueous thiocyanate media were investigated by a batch process. The maximum sorption of U(VI) was in the pH ranges 1-4. The kinetics of sorption of the U(VI) by the Grafted-PUF were found to be fast with half life of sorption (t(1/2)) in 2.43min. The average sorption capacity of different sorbents 0.124meqg(-1) for uranyl ions, enrichment factors approximately 40 and the recovery 98-100% were achieved (R.S.D. approximately 0.73%). The basic dyestuff Grafted-PUF could be used many times without decreasing their capacities significantly. The value of the Gibbs free energy (DeltaG) for the sorbents is -7.3kJmol(-1), which reflects the spontaneous nature of sorption process. The sorption mechanism of the metal ion onto Grafted-PUF was also discussed. PMID:19071294

  15. Investigation of physico-chemical characteristics of size-segregated particulate matter in a metropolitan environment and their impact on air quality in southern California

    NASA Astrophysics Data System (ADS)

    Pakbin, Payam

    Numerous epidemiological studies have associated the adverse respiratory and cardiovascular effects to atmospheric particulate matter (PM) exposure. There is ample literature providing evidence of adverse effects for all inhalable particle size ranges, however the biological mechanisms responsible for the toxicity of PM are still uncertain. Due to the lack of data about how different PM components act in a complex mixture, it is not possible to precisely quantify the contributions from the main sources and components to the effects on human health. Thus, PM in health impact assessments is usually regarded as a uniform pollutant, regardless of the contribution from different sources, and assuming the same effect on morality. This is probably not a correct assumption, but is a pragmatic compromise while waiting for sufficient knowledge that will allow the use of indicators other than particle mass. As a result linking the toxicity of PM with several of its chemical components has been the focus of considerable research over the past decade. The associations between health endpoints with the hundreds of potentially toxic chemical species and PM characteristics may be daunting and not cost efficient. Therefore it is desirable to focus on the casualty of the few critical chemical components that current science supports as potentially the most harmful to human health. Such information will allow for more effective regulatory control strategies, more targeted air quality standards, and as a result, reductions in population exposure to the most harmful types of airborne PM. The current particulate matter emission standards are based on PM mass only. However, the prevailing scientific opinion contends that PM mass is a surrogate measure of other physical and chemical properties of PM that are the actual causes of the observed health effects. In this study we focus on the PM components that are not currently regulated, while there is ample evidence that they can cause

  16. Isotopic anomalies of Ne, Xe, and C in meteorites. I - Separation of carriers by density and chemical resistance

    NASA Technical Reports Server (NTRS)

    Ming, Tang; Lewis, Roy S.; Anders, Edward; Grady, M. M.; Wright, I. P.

    1988-01-01

    The carriers of presolar noble gases were studied by isotopically analyzing 19 separates from the Murray and Murchison C2 chondrites for Ne, Xe, C, and N. It is found that the carriers of Ne-E(H) and Xe-S are resistant to HCl, HF, boiling HClO4, and CrO3-H2SO4, and thus must be either diamond or some resistant carbide or oxide. The carrier of Ne-E(L) may be some form of amorphous carbon with delta C13 of about +340 percent. A new carbon component, C theta, found as 0.2-2-micron inclusions in Murchison spinel, is amorphous and contains little or no noble gas. A new heavy nitrogen component is found which has an abundance of about 1 ppm in the bulk meteorite, combusts at 450-500 C, and may be associated wtih isotopically normal carbon or with C-alpha.

  17. Isotopic anomalies of Ne, Xe, and C in meteorites. I - Separation of carriers by density and chemical resistance

    NASA Astrophysics Data System (ADS)

    Ming, T.; Lewis, R. S.; Anders, E.; Grady, M. M.; Wright, I. P.; Pillinger, C. T.

    1988-05-01

    The carriers of presolar noble gases were studied by isotopically analyzing 19 separates from the Murray and Murchison C2 chondrites for Ne, Xe, C, and N. It is found that the carriers of Ne-E(H) and Xe-S are resistant to HCl, HF, boiling HClO4, and CrO3-H2SO4, and thus must be either diamond or some resistant carbide or oxide. The carrier of Ne-E(L) may be some form of amorphous carbon with delta C13 of about +340 percent. A new carbon component, C theta, found as 0.2-2-micron inclusions in Murchison spinel, is amorphous and contains little or no noble gas. A new heavy nitrogen component is found which has an abundance of about 1 ppm in the bulk meteorite, combusts at 450-500 C, and may be associated wtih isotopically normal carbon or with C-alpha.

  18. Potential significance of photoexcited NO2 on global air quality with the NMMB/BSC chemical transport model

    NASA Astrophysics Data System (ADS)

    Jorba, O.; Dabdub, D.; Blaszczak-Boxe, C.; PéRez, C.; Janjic, Z.; Baldasano, J. M.; Spada, M.; Badia, A.; GonçAlves, M.

    2012-07-01

    Atmospheric chemists have recently focused on the relevance of the NO2* + H2O → OH + HONO reaction to local air quality. This chemistry has been considered not relevant for the troposphere from known reaction rates until nowadays. New experiments suggested a rate constant of 1.7 × 10-13 cm3 molecule-1 s-1, which is an order of magnitude faster than the previously estimated upper limit of 1.2 × 10-14 cm3 molecule-1 s-1, determined by Crowley and Carl (1997). Using the new global model, NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM), simulations are presented that assess the potential significance of this chemistry on global air quality. Results show that if the NO2* chemistry is considered following the upper limit kinetics recommended by Crowley and Carl (1997), it produces an enhancement of ozone surface concentrations of 4-6 ppbv in rural areas and 6-15 ppbv in urban locations, reaching a maximum enhancement of 30 ppbv in eastern Asia. Moreover, NO2 enhancements are minor (<0.01 ppbv) in background regions and reach maximum daytime values of 1-6 ppbv. Similarly, HONO exhibits negligible increases, 8-9 pptv in urban settings. Enhancements in the concentration of OH are around 14-17 × 105 molec cm-3. Decreases in the concentration of O3 and its precursors are also identified but to a lesser degree. In order to quantify the role of the two kinetic rates measured, model simulations are compared after incorporating both reaction rate constants. Maximum O3 difference enhancements from 5 to 10 ppbv are modeled over locations where high NOx emissions are present; however, differences are small in most parts of the globe.

  19. Continuous estimation of baseflow in snowmelt-dominated streams and rivers in the Upper Colorado River Basin: A chemical hydrograph separation approach

    USGS Publications Warehouse

    Miller, Matthew P.; Susong, David D.; Shope, Christopher L.; Heilweil, Victor M.; Stolp, Bernard J.

    2014-01-01

    Effective science-based management of water resources in large basins requires a qualitative understanding of hydrologic conditions and quantitative measures of the various components of the water budget, including difficult to measure components such as baseflow discharge to streams. Using widely available discharge and continuously collected specific conductance (SC) data, we adapted and applied a long established chemical hydrograph separation approach to quantify daily and representative annual baseflow discharge at fourteen streams and rivers at large spatial (> 1,000 km2 watersheds) and temporal (up to 37 years) scales in the Upper Colorado River Basin. On average, annual baseflow was 21-58% of annual stream discharge, 13-45% of discharge during snowmelt, and 40-86% of discharge during low-flow conditions. Results suggest that reservoirs may act to store baseflow discharged to the stream during snowmelt and release that baseflow during low-flow conditions, and that irrigation return flows may contribute to increases in fall baseflow in heavily irrigated watersheds. The chemical hydrograph separation approach, and associated conceptual model defined here provide a basis for the identification of land use, management, and climate effects on baseflow.

  20. Applying Chemical Potential and Partial Pressure Concepts to Understand the Spontaneous Mixing of Helium and Air in a Helium-Inflated Balloon

    ERIC Educational Resources Information Center

    Jee-Yon Lee; Hee-Soo Yoo; Jong Sook Park; Kwang-Jin Hwang; Jin Seog Kim

    2005-01-01

    The spontaneous mixing of helium and air in a helium-inflated balloon is described in an experiment in which the partial pressure of the gases in the balloon are determined from the mole factions and the total pressure measured in the balloon. The results described provide a model for teaching concepts of partial pressure, chemical potential, and…

  1. Formic and Acetic Acid Observations over Colorado by Chemical Ionization Mass Spectrometry and Organic Acids' Role in Air Quality

    NASA Astrophysics Data System (ADS)

    Treadaway, V.; O'Sullivan, D. W.; Heikes, B.; Silwal, I.; McNeill, A.

    2015-12-01

    Formic acid (HFo) and acetic acid (HAc) have both natural and anthropogenic sources and a role in the atmospheric processing of carbon. These organic acids also have an increasing importance in setting the acidity of rain and snow as precipitation nitrate and sulfate concentrations have decreased. Primary emissions for both organic acids include biomass burning, agriculture, and motor vehicle emissions. Secondary production is also a substantial source for both acids especially from biogenic precursors, secondary organic aerosols (SOAs), and photochemical production from volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). Chemical transport models underestimate organic acid concentrations and recent research has sought to develop additional production mechanisms. Here we report HFo and HAc measurements during two campaigns over Colorado using the peroxide chemical ionization mass spectrometer (PCIMS). Iodide clusters of both HFo and HAc were recorded at mass-to-charge ratios of 173 and 187, respectively. The PCIMS was flown aboard the NCAR Gulfstream-V platform during the Deep Convective Clouds and Chemistry Experiment (DC3) and aboard the NCAR C-130 during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE). The DC3 observations were made in May and June 2012 extending from the surface to 13 km over the central and eastern United States. FRAPPE observations were made in July and August 2014 from the surface to 7 km over Colorado. DC3 measurements reported here are focused over the Colorado Front Range and complement the FRAPPE observations. DC3 HFo altitude profiles are characterized by a decrease up to 6 km followed by an increase either back to boundary layer mixing ratio values or higher (a "C" shape). Organic acid measurements from both campaigns are interpreted with an emphasis on emission sources (both natural and anthropogenic) over Colorado and in situ photochemical production especially ozone precursors.

  2. Comparing three vegetation monoterpene emission models to measured gas concentrations with a model of meteorology, air chemistry and chemical transport

    NASA Astrophysics Data System (ADS)

    Smolander, S.; He, Q.; Mogensen, D.; Zhou, L.; Bäck, J.; Ruuskanen, T.; Noe, S.; Guenther, A.; Aaltonen, H.; Kulmala, M.; Boy, M.

    2014-10-01

    Biogenic volatile organic compounds (BVOCs) are essential in atmospheric chemistry because of their chemical reactions that produce and destroy tropospheric ozone, their effects on aerosol formation and growth, and their potential influence on global warming. As one of the important BVOC groups, monoterpenes have been a focus of scientific attention in atmospheric research. Detailed regional measurements and model estimates are needed to study emission potential and the monoterpene budget on a global scale. Since the use of empirical measurements for upscaling is limited by many physical and biological factors, such as genetic variation, temperature and light, water availability, seasonal changes, and environmental stresses, comprehensive inventories over larger areas are difficult to obtain. We applied the boundary-layer-chemistry-transport model SOSA (model to Simulate the concentrations of Organic vapours and Sulphuric Acid) to investigate Scots pine (Pinus sylvestris) monoterpene emissions in a boreal coniferous forest at the SMEAR (Station for Measuring forest Ecosystem-Atmosphere Relations) II site, southern Finland. SOSA was applied to simulate monoterpene emissions with three different emission modules: the semiempirical G95, MEGAN (Model of Emissions of Gases and Aerosols from Nature) 2.04 with improved descriptions of temperature and light responses and including also carbonyl emissions, and a process-based model SIM-BIM (Seasonal Isoprenoid synthase Model - Biochemical Isoprenoid biosynthesis Model). For the first time, the emission models included seasonal and diurnal variations in both quantity and chemical species of emitted monoterpenes, based on parameterizations obtained from field measurements. Results indicate that modelling and observations agreed reasonably well and that the model can be used for investigating regional air chemistry questions related to monoterpenes. The predominant modelled monoterpene concentrations, α-pinene and Δ3-carene

  3. Automated radioanalytical system incorporating microwave-assisted sample preparation, chemical separation, and online radiometric detection for the monitoring of total 99Tc in nuclear waste processing streams.

    PubMed

    Egorov, Oleg B; O'Hara, Matthew J; Grate, Jay W

    2012-04-01

    An automated fluidic instrument is described that rapidly determines the total (99)Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the (99)Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of (99)Tc. We developed a preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of (99)Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site. PMID:22440010

  4. Automated Radioanalytical System Incorporating Microwave-Assisted Sample Preparation, Chemical Separation, and Online Radiometric Detection for the Monitoring of Total 99Tc in Nuclear Waste Processing Streams

    SciTech Connect

    Egorov, Oleg; O'Hara, Matthew J.; Grate, Jay W.

    2012-04-03

    An automated fluidic instrument is described that rapidly determines the total 99Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the 99Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of 99Tc. We developed a preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of 99Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site.

  5. Environmental Assessment for the Commercial Demonstration of the Low NOx Burner/Separated Over-Fire Air (LNB/SOFA) Integration System Emission Reduction Technology, Finney County, Kansas

    SciTech Connect

    n /a

    2003-03-11

    The U.S. Department of Energy (DOE) proposes to provide partial funding to the Sunflower Electric Power Corporation (Sunflower), to demonstrate the commercial application of Low-NO{sub x} Burner/Separated Over-Fire Air (LNB/SOFA) integration system to achieve NO{sub x} emission reduction to the level of 0.15 to 0.22 pounds per million British thermal units (lb/MM Btu). The proposed project station is Sunflower's 360 MW coal-fired generation station, Holcomb Unit No. 1 (Holcomb Station). The station, fueled by coal from Wyoming's Powder River Basin, is located near Garden City, in Finney County, Kansas. The period of performance is expected to last approximately 2 years. The Holcomb Station, Sunflower LNB/SOFA integrated system would be modified in three distinct phases to demonstrate the synergistic effect of layering NO{sub x} control technologies. Once modified, the station would demonstrate that a unit equipped with an existing low-NO{sub x} burner system can be retrofitted with a new separated over-fire air (SOFA) system, coal flow measurement and control, and enhanced combustion monitoring to achieve about 45 percent reduction in nitrogen oxides (NO{sub x}) emissions. The proposed project would demonstrate a technology alternative to Selective Catalytic Reduction (SCR) systems. While SCR does generally achieve high reductions in NO{sub x} emissions (from about 0.8 lb/MM to 0.12 lb/MM Btu), it does so at higher capital and operating cost, requires the extensive use of critical construction labor, requires longer periods of unit outage for deployment, and generally requires longer periods of time to complete shakedown and full-scale operation. Cost of the proposed project technology would be on the order of 15-25 percent of that for SCR, with consequential benefits derived from reductions in construction manpower requirements and periods of power outages. This proposed technology demonstration would generally be applicable to boilers using opposed-wall burners

  6. Cell-surface modification of non-GMO without chemical treatment by novel GMO-coupled and -separated cocultivation method.

    PubMed

    Miura, Natsuko; Aoki, Wataru; Tokumoto, Naoki; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2009-02-01

    We developed a novel method to coat living non-genetically modified (GM) cells with functional recombinant proteins. First, we prepared GM yeast to secrete constructed proteins that have two domains: a functional domain and a binding domain that recognizes other cells. Second, we cocultivated GM and non-GM yeasts that share and coutilize the medium containing recombinant proteins produced by GM yeasts using a filter-membrane-separated cultivation reactor. We confirmed that GM yeast secreted enhanced green fluorescent protein (EGFP) fusion proteins to culture medium. After cocultivation, EGFP fusion proteins produced by GM yeast were targeted to non-GM yeast (Saccharomyces cerevisiae BY4741DeltaCYC8 strain) cell surface. Yeast cell-surface engineering is a useful method that enables the coating of GM yeast cell surface with recombinant proteins to produce highly stable and accumulated protein particles. The results of this study suggest that development of cell-surface engineering from GM organisms (GMOs) to living non-GMOs by our novel cocultivation method is possible. PMID:19039583

  7. Characterization of Diesel Fuel by Chemical Separation Combined with Capillary Gas Chromatography (GC) Isotope Ratio Mass Spectrometry (IRMS)

    SciTech Connect

    Harvey, Scott D.; Jarman, Kristin H.; Moran, James J.; Sorensen, Christina M.; Wright, Bob W.

    2011-09-15

    The purpose of this study was to perform a preliminary investigation of compound-specific isotope analysis (CSIA) of diesel fuels to evaluate whether the technique could distinguish between the diesel samples from different sources/locations. The ability to differentiate or correlate diesel samples could be valuable for detecting fuel tax evasion schemes. Two fractionation techniques were used to isolate the n-alkanes from the fuel. Both δ13C and δD values for the n-alkanes were then determined by CSIA in each sample. Plots of δD versus δ13C with sample n-alkane points connected in order of increasing carbon number gave well separated clusters with characteristic shapes for each sample. Principal components analysis (PCA) with δ13C, δD, or combined δ13C and δD data on the yielded scores plots that could clearly differentiate the samples, thereby demonstrating the potential of this approach for fingerprinting fuel samples using the δ13C and δD values.

  8. Characteristics of the chemical forms of 11C, 13N, and 15O induced in air by the operation of a 100 MeV electron linear accelerator.

    PubMed

    Endo, A; Kikuchi, M; Izawa, S; Ikezawa, Y

    1995-01-01

    To characterize airborne radioactivity induced by the operation of high-energy accelerators, the fractions of aerosol and gaseous components, and the chemical forms of 11C, 13N, and 15O produced in the air of a target room of a 100 MeV electron linear accelerator were studied. Measurements of radioactivity using a particulate air sampling filter and a gas flow-through ionization chamber showed that more than 98% of 11C, 13N, and 15O were present as gaseous forms. Their chemical forms, detected by means of radio-gas chromatography, were 11C as CO2; 13N as N2 and NO; and 15O as O2 and NO. Machine operating conditions, which affect the compositions of the induced radionuclides and of their chemical forms, and the resulting effect on the estimation of internal doses are discussed. PMID:7989199

  9. Conducting polymer actuator based on chemically deposited polypyrrole and polyurethane-based solid polymer electrolyte working in air

    NASA Astrophysics Data System (ADS)

    Choi, Hwa-Jeong; Song, Young-Min; Chung, Ildoo; Ryu, Kwang-Sun; Jo, Nam-Ju

    2009-02-01

    Conducting polymers (CPs), such as polypyrrole, polythiophene, and polyaniline, are unique in that they have switchable properties due to their two or more mechanically stable oxidation states. Thus, their films or coatings can be easily switched by the application of a small voltage and current to change their volume during electrochemical redox processes. In particular, polypyrrole (PPy) has been studied most extensively because of its high electrical conductivity and good environmental stability under ambient conditions. In this work, we have studied a new CP actuator, fully polymeric, assembled with two PPy film electrodes and a solid polymer electrolyte (SPE), polyurethane/Mg(ClO4)2. Polyurethanes (PUs) were synthesized from 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and three types of polyol: poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and PPG-block-PEG-block-PPG (PPG-co-PEG). The chemical polymerization of PPy by immersion in Py monomer aqueous solution and oxidant aqueous solution is an adequate method to prepare PU/PPy composite film as an actuator. To find the proper thickness of the PPy coating layer for actuation, we measured the displacements of the actuators according to the thickness of the PPy coating layer. The displacement of all actuators is discussed in connection with the properties of the SPE and PPy. All the results obtained in this work show the feasibility of electrochemomechanical devices based on PPy and SPE film being able to work in air.

  10. CP actuator based on chemically-deposited polypyrrole and PU based solid polymer electrolyte working in air

    NASA Astrophysics Data System (ADS)

    Choi, Hwa Jeong; Lim, Hyun-Ok; Chung, Ildoo; Ryu, Kwang-Sun; Jo, Nam-Ju

    2007-07-01

    Conducting polymers (CPs), such as polypyrrole, polythiophene and polyaniline, are unique in that they have switchable properties due to their two or more mechanically stable oxidation state. Thus, their films or coatings can be easily switched by the application of small voltage and current to change volume during their electrochemical redox process. In particular, polypyrrole (PPy) has been studied most extensively because of its high electrical conductivity and good environmental stability under ambient condition. In this work, we have studied a new CP actuator, fully polymeric, assembled with two PPy film electrodes and a solid polymer electrolyte (SPE), polyurethane/Mg(ClO 4) II. Polyurethanes (PUs) were synthesized from 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and three types of polyols, poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and PPG-block-PEG-block-PPG (PPG-co-PEG). The chemical polymerization of PPy by immersion in Py monomer aqueous solution and oxidant aqueous solution is an adequate method to prepare PU/PPy composite film as actuator. To find the proper thickness of PPy coating layer for actuation, we measured the displacement of actuators according to the thickness of PPy coating layer. And, the displacement of all actuators was discussed in connection with the properties of SPE and PPy. All the results obtained in this work show the feasibility of electrochemomechanical devices based on PPy and SPE film able to work in air.

  11. A fully-coupled implicit method for thermo-chemical nonequilibrium air at sub-orbital flight speeds

    NASA Technical Reports Server (NTRS)

    Park, Chul; Yoon, Seokkwan

    1989-01-01

    A CFD technique is described in which the finite-rate chemistry in thermal and chemical nonequilibrium air is fully and implicitly coupled with the fluid motion. Developed for use in the suborbital hypersonic flight speed range, the method accounts for nonequilibrium vibrational and electronic excitation and dissociation, but not ionization. The steady-state solution to the resulting system of equations is obtained by using a lower-upper factorization and symmetric Gauss-Seidel sweeping technique through Newton iteration. Inversion of the left-hand-side matrices is replaced by scalar multiplications through the use of the diagonal dominance algorithm. The code, named CENS2H (Compressible-Euler-Navier-Stokes Two-Dimensional Hypersonic), is fully vectorized and requires about 8.8 x 10 to the -5th sec per node point per iteration using a Cray X-MP computer. Converged solutions are obtained after about 2400 iterations. Sample calculations are made for a circular cylinder and a 10 percent airfoil at 5 deg angle of attack. The calculated cylinder flow field agrees with that obtained experimentally. The code predicts a 10 percent change in lift, drag, and pitching moment for the airfoil due to the thermochemical phenomena.

  12. Growth of CdS thin films on indium coated glass substrates via chemical bath deposition and subsequent air annealing

    NASA Astrophysics Data System (ADS)

    Ghosh, Biswajit; Kumar, Kamlesh; Singh, Balwant Kr; Banerjee, Pushan; Das, Subrata

    2014-11-01

    In the present work attempts were made to synthesize indium doped CdS films by fabricating In/CdS bilayers using CBD-CdS on vacuum evaporated In thin films and subsequent air annealing. 135 nm CdS films were grown onto 20 nm and 35 nm indium coated glass substrate employing chemical bath deposition technique. The In/CdS bilayers thus formed were subjected to heat treatment at the temperatures between 200 and 400 °C for 4 min in the muffle furnace to facilitate indium to diffuse into the CdS films. XRD pattern ascertained no noticeable shift in lattice constant implying grain boundary metal segregation, while secondary ion mass spectrometry indicated the diffusion profile of indium into CdS matrices. Mass spectrometry results showed that substantial diffusion of indium had been taken place within CdS at 400 °C. Dark and photocurrent with different illumination time were measured to ascertain the photosensitivity of pure and composite CdS films.

  13. Chemical reactivity of aprotic electrolytes on a solid Li2O2 surface: screening solvents for Li-air batteries

    NASA Astrophysics Data System (ADS)

    Laino, Teodoro; Curioni, Alessandro

    2013-09-01

    Nowadays, simulation techniques are routinely used to generate accurate models of the structures of crystalline and amorphous solids, to study surfaces, defects and the properties of complex systems, and to screen possible candidate materials for the most diverse types of technological applications. The screening of novel molecular structures has been so far pursued by calculation of intrinsic properties with first-principle methods. Still, the use of intrinsic properties as scoring functions may not always be optimal for systems of high complexity. In these cases, increasingly detailed and realistic simulations that take into account the interaction with the surrounding molecules are of crucial importance. In this paper, we present an effective way to screen different solvents with respect to their chemical stability versus Li2O2 solid particles. To achieve this, the minimum energy paths for different types of reactions of a series of aprotic solvents (acetonitrile and pivalonitrile, dimethyl sulphoxide, N-methyl-2-pyrrolidone and some of its derivatives, penta ethylene glycol (PEG-5) and a fluorinated derivative) with solid Li2O2 are computed and reported. From these data, we can extract the reaction energy barriers, which compare extremely well with the available experimental data and offer a convenient way for screening and designing suitable solvents for Li-air batteries from first-principle calculations.

  14. Chemical constituents of ambient particulate air pollution and biomarkers of inflammation, coagulation and homocysteine in healthy adults: A prospective panel study

    PubMed Central

    2012-01-01

    Background Ambient air pollution has been associated with activation of systemic inflammation and hypercoagulability and increased plasma homocysteine, but the chemical constituents behind the association are not well understood. We examined the relations of various chemical constituents of fine particles (PM2.5) and biomarkers of inflammation, coagulation and homocysteine in the context of traffic-related air pollution. Methods A panel of 40 healthy college students underwent biweekly blood collection for 12 times before and after their relocation from a suburban campus to an urban campus with changing air pollution contents in Beijing. Blood samples were measured for circulatory biomarkers of high-sensitivity C reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), fibrinogen, plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator (t-PA), von Willebrand factor (vWF), soluble platelet selectin (sP-selectin), and total homocysteine (tHcy). Various air pollutants were measured in a central air-monitoring station in each campus and 32 PM2.5 chemical constituents were determined in the laboratory. We used three different mixed-effects models (single-constituent model, constituent-PM2.5 joint model and constituent residual model) controlling for potential confounders to estimate the effects of PM2.5 chemical constituents on circulatory biomarkers. Results We found consistent positive associations between the following biomarkers and PM2.5 chemical constituents across different models: TNF-α with secondary organic carbon, chloride, zinc, molybdenum and stannum; fibrinogen with magnesium, iron, titanium, cobalt and cadmium; PAI-1 with titanium, cobalt and manganese; t-PA with cadmium and selenium; vWF with aluminum. We also found consistent inverse associations of vWF with nitrate, chloride and sodium, and sP-selectin with manganese. Two positive associations of zinc with TNF-α and of cobalt with fibrinogen, and two inverse

  15. Modeling the Transport and Chemical Evolution of Onshore and Offshore Emissions and their Impact on Local and Regional Air Quality Using a Variable-Grid-Resolution Air Quality Model

    SciTech Connect

    Kiran Alapaty; Adel Hanna

    2006-10-16

    This research project has two primary objectives: (1) to further develop and refine the Multiscale Air Quality Simulation Platform-Variable Grid Resolution (MAQSIP-VGR) model, an advanced variable-grid-resolution air quality model, to provide detailed, accurate representation of the dynamical and chemical processes governing the fate of anthropogenic emissions in coastal environments; and (2) to improve current understanding of the potential impact of onshore and offshore oil and gas exploration and production (E&P) emissions on O{sub 3} and particulate matter nonattainment in the Gulf of Mexico and surrounding states.

  16. Examining the temperature dependence of ethanol (E85) versus gasoline emissions on air pollution with a largely-explicit chemical mechanism

    NASA Astrophysics Data System (ADS)

    Ginnebaugh, Diana L.; Liang, Jinyou; Jacobson, Mark Z.

    2010-03-01

    The increased use of ethanol in transportation fuels warrants an investigation of its consequences. An important component of such an investigation is the temperature dependence of ethanol and gasoline exhaust chemistry. We use the Master Chemical Mechanism (MCM, version 3.1, LEEDS University) with the SMVGEAR II chemical ordinary differential solver to provide the speed necessary to simulate complex chemistry to examine such effects. The MCM has over 13,500 organic reactions and 4600 species. SMVGEAR II is a sparse-matrix Gear solver that reduces the computation time significantly while maintaining any specified accuracy. Although we use a box model for this study, we determine and demonstrate in a separate study that the speed of the MCM with SMVGEAR II allows the MCM to be modeled in 3-dimensions. We also verified the accuracy of the model in comparison with smog chamber data. We then use the model with species-resolved tailpipe emissions data for E85 (15% gasoline, 85% ethanol fuel blend) and gasoline vehicles to compare the impact of each on nitrogen oxides, organic gases, and ozone as a function of ambient temperature and background concentrations, using Los Angeles in 2020 as a base case. We use two different emissions sets - one is a compilation of exhaust and evaporative data taken near 24 °C and the other from exhaust data taken at -7 °C - to determine how atmospheric chemistry and emissions are affected by temperature. We include diurnal effects by examining two day scenarios. We find that, accounting for chemistry and dilution alone, the average ozone concentrations through the range of temperatures tested are higher with E85 than with gasoline by ˜7 part per billion volume (ppbv) at higher temperatures (summer conditions) to ˜39 ppbv at low temperatures and low sunlight (winter conditions) for an area with a high nitrogen oxide (NOx) to non-methane organic gas (NMOG) ratio. The results suggest that E85's effect on health through ozone formation

  17. Co-assembly of CdTe and Fe3O4 with molecularly imprinted polymer for recognition and separation of endocrine disrupting chemicals

    NASA Astrophysics Data System (ADS)

    Chang, Limin; Chen, Shaona; Chu, Jia; Li, Xin

    2013-11-01

    In this study, we present a general protocol to fabricate imprinting matrix co-loaded with CdTe quantum dots and Fe3O4 nanoparticles for the recognition of endocrine disrupting chemicals (EDCs). The resultant composites were characterized by transmission electron microscopy, fluorescence spectroscopy, and energy dispersive spectroscopy. The materials have been demonstrated to be characterized with spherical shape with a saturation magnetization value of 1.7 emu g-1. Furthermore, the rebinding experiments show that the resultant materials have greater affinity and selectivity towards p-nitrophenol (model EDCs) over structurally related compounds. We believe that the effective method proposed in this work might provide a platform to prepare magnetic and fluorescent molecularly imprinted polymers for the recognition and separation of EDCs.

  18. Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass

    DOEpatents

    Miller, C.M.; Nogar, N.S.

    1982-09-02

    Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

  19. Application of chemical, biological and membrane separation processes in textile industry with recourse to zero effluent discharge--a case study.

    PubMed

    Nandy, T; Dhodapkar, R S; Pophali, G R; Kaul, S N; Devotta, S

    2005-09-01

    Environmental concerns associated with textile processing had placed the textile sector in a Southern State of India under serious threat of survival. The textile industries were closed under the orders of the Statutory Board for reason of inadequate compliance to environmental discharge norms of the State for the protection of the drinking water source of the State capital. In compliance with the direction of the Board for zero effluent discharge, advanced treatment process have been implemented for recovery of boiler feed quality water with recourse to effluent recycling/reuse. The paper describes to a case study on the adequacy assessment of the full scale effluent treatment plant comprising chemical, biological and filtration processes in a small scale textile industry. In addition, implementation of measures for discernable improvement in the performance of the existing units through effective operation & maintenance, and application of membrane separation processes leading to zero effluent discharge is also highlighted. PMID:16196413

  20. Unique battery with an active membrane separator having uniform physico-chemically functionalized ion channels and a method making the same

    DOEpatents

    Gerald, II, Rex E.; Ruscic, Katarina J.; Sears, Devin N.; Smith, Luis J.; Klingler, Robert J.; Rathke, Jerome W.

    2012-02-21

    The invention relates to a unique battery having an active, porous membrane and method of making the same. More specifically the invention relates to a sealed battery system having a porous, metal oxide membrane with uniform, physicochemically functionalized ion channels capable of adjustable ionic interaction. The physicochemically-active porous membrane purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

  1. Physical and chemical processes of air masses in the Aegean Sea during Etesians: Aegean-GAME airborne campaign.

    PubMed

    Tombrou, M; Bossioli, E; Kalogiros, J; Allan, J D; Bacak, A; Biskos, G; Coe, H; Dandou, A; Kouvarakis, G; Mihalopoulos, N; Percival, C J; Protonotariou, A P; Szabó-Takács, B

    2015-02-15

    High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 ± 76 ppbv for CO, 62.5 ± 4.1 ppbv for O3, 5.0 ± 1.1 μg m(-3) for sulfate, 4.7 ± 0.9 μg m(-3) for organic mass and 0.5 ± 0.2 μg m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport. PMID:25460953

  2. Association between particulate matter and its chemical constituents of urban air pollution and daily mortality or morbidity in Beijing City.

    PubMed

    Li, Pei; Xin, Jinyuan; Wang, Yuesi; Li, Guoxing; Pan, Xiaochuan; Wang, Shigong; Cheng, Mengtian; Wen, Tianxue; Wang, Guangcheng; Liu, Zirui

    2015-01-01

    Recent time series studies have indicated that daily mortality and morbidity are associated with particulate matters. However, about the relative effects and its seasonal patterns of fine particulate matter constituents is particularly limited in developing Asian countries. In this study, we examined the role of particulate matters and its key chemical components of fine particles on both mortality and morbidity in Beijing. We applied several overdispersed Poisson generalized nonlinear models, adjusting for time, day of week, holiday, temperature, and relative humidity, to investigate the association between risk of mortality or morbidity and particulate matters and its constituents in Beijing, China, for January 2005 through December 2009. Particles and several constituents were associated with multiple mortality or morbidity categories, especially on respiratory health. For a 3-day lag, the nonaccident mortality increased by 1.52, 0.19, 1.03, 0.56, 0.42, and 0.32% for particulate matter (PM)2.5, PM10, K(+), SO4(2-), Ca(2+), and NO3(-) based on interquartile ranges of 36.00, 64.00, 0.41, 8.75, 1.43, and 2.24 μg/m(3), respectively. The estimates of short-term effects for PM2.5 and its components in the cold season were 1 ~ 6 times higher than that in the full year on these health outcomes. Most of components had stronger adverse effects on human health in the heavy PM2.5 mass concentrations, especially for K(+), NO3(-), and SO4(2-). This analysis added to the growing body of evidence linking PM2.5 with mortality or morbidity and indicated that excess risks may vary among specific PM2.5 components. Combustion-related products, traffic sources, vegetative burning, and crustal component and resuspended road dust may play a key role in the associations between air pollution and public health in Beijing. PMID:25074829

  3. Differential chemical derivatization integrated with chromatographic separation for analysis of isomeric sialylated N-glycans: a nano-hydrophilic interaction liquid chromatography-MS platform.

    PubMed

    Tousi, Fateme; Bones, Jonathan; Hancock, William S; Hincapie, Marina

    2013-09-01

    MS analysis of sialylated glycans is challenging due to their low ionization efficiency in positive ion mode as well as the possibility of in-source fragmentation. Chemical derivatization strategies have been developed to address this issue focused on removal of the labile acidic proton prior to MS analysis. Highly sialylated negatively charged glycans also exhibit high retention and unsatisfactory separation efficiency when analyzed by hydrophilic interaction liquid chromatography (HILIC) due to their high polarity. Here, we combined linkage specific derivatization of sialic acids by reaction with the condensation reagent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) in methanol with nanoscale liquid chromatographic separation prior to accurate mass Orbitrap MS analysis. Coupling DMT-MM charge neutralization of sialic acids with nano-HILIC-Orbitrap-MS not only allows for linkage specific characterization of sialylated glycans directly from the precursor mass but also improves the preceding HILIC separation by increasing the hydrophobicity and altering the selectivity of the oligosaccharide analytes. We focused on the trisialylated N-glycan fraction from haptoglobin and human plasma, enriched using weak anion exchange chromatography, as this trisialylated fraction has been linked with cancer associated changes in the serum N-glycome. The developed methodology was applied to investigate whether structural alterations in this oligosaccharide pool, enriched from the sera of pathological stage and sex matched patients bearing lung, breast, ovarian, pancreatic, or gastric cancer, demonstrate any degree of cancer specificity or whether changes in expression levels are purely cancer associated. The results of this pilot study indicate limited degrees of cancer specificity, particularly for pancreatic cancer, based on alterations in the relative abundance of specific trisialylated isomers. PMID:23901877

  4. Impact of air-exposure on the chemical and electronic structure ofZnO:Zn3N2 thin films

    SciTech Connect

    Bar, M.; Ahn, K.-S.; Shet, S.; Yan, Y.; Weinhardt, L.; Fuchs, O.; Blum, M.; Pookpanratana, S.; George, K.; Yang, W.; Denlinger, J.D.; Al-Jassim, M.; Heske, C.

    2008-09-08

    The chemical and electronic surface structure of ZnO:Zn3N2 ("ZnO:N") thin films with different N contents was investigated by soft x-ray emission spectroscopy. Upon exposure to ambient air (in contrast to storage in vacuum), the chemical and electronic surface structure of the ZnO:N films changes substantially. In particular, we find that the Zn3N2/(Zn3N2+ZnO) ratio decreases with exposure time and that this change depends on the initial N content. We suggest a degradation mechanism based on the reaction of the Zn3N2 content with atmospheric humidity.

  5. Calibration of Rainfall-Runoff Model by Referring to Hydrological Separation of Runoff Components using Chemical and Isotopic Characteristics of Discharge

    NASA Astrophysics Data System (ADS)

    Chikamori, H.

    2008-12-01

    Calibration of Rainfall-Runoff Model by Referring to Hydrological Separation of Runoff Components using Chemical and Isotopic Characteristics of Discharge Hidetaka Chikamori Graduate School of Environmental Science, Okayama University, JAPAN A rainfall-runoff model is generally calibrated by minimizing error in calculated runoff using records of hydrological components, that is, observed rainfall, discharge and observed or estimated evapotranpiration. However, calibration using only hydrological components sometimes produces a model with strange structure that does not reflect physical properties of an objective basin. It is probably due to error in referred hydrological records. In this study, the author calibrated a rainfall runoff model using not only hydrological record but also chemical and isotopic data of discharge so as to obtain a reasonably structured model from multiple viewpoints. Besides, the model structure was improved in order to simulate isotopic characteristics well. It is well known that ratio of surface flow in total flow can be estimated by change in concentration of cation or anion. Relative concentration of 18O, δ18O is well used for separating runoff of retained water in soil as "old water" from total runoff. A Long-and-Short Term Tank Model (LST2 Model) was applied to three Hinoki Cypress catchments in Mie experimental basin located in the middle of Japan. One of these catchments is of well-maintained planted forest, and two are of poor-maintained planted. A model was calibrated by Differential Evolution for each catchment using hydrological data, concentration of K+ and δ18O. In these catchments, Gomi et al (2008) showed that concentration of K+ well expresses ratio of surface runoff to total runoff, and that δ18O subsurface runoff to total runoff. The results show that an original version of LST2 Model cannot simulated delayed subsurface flow ratio estimated by δ18O, although it well simulates surface flow ratio estimated by

  6. Separating the influence of projected changes in air temperature and wind on patterns of sea level change and ocean heat content

    NASA Astrophysics Data System (ADS)

    Saenko, Oleg A.; Yang, Duo; Gregory, Jonathan M.; Spence, Paul; Myers, Paul G.

    2015-08-01

    We present ocean model sensitivity experiments aimed at separating the influence of the projected changes in the "thermal" (near-surface air temperature) and "wind" (near-surface winds) forcing on the patterns of sea level and ocean heat content. In the North Atlantic, the distribution of sea level change is more due to the "thermal" forcing, whereas it is more due to the "wind" forcing in the North Pacific; in the Southern Ocean, the "thermal" and "wind" forcing have a comparable influence. In the ocean adjacent to Antarctica the "thermal" forcing leads to an inflow of warmer waters on the continental shelves, which is somewhat attenuated by the "wind" forcing. The structure of the vertically integrated heat uptake is set by different processes at low and high latitudes: at low latitudes it is dominated by the heat transport convergence, whereas at high latitudes it represents a small residual of changes in the surface flux and advection of heat. The structure of the horizontally integrated heat content tendency is set by the increase of downward heat flux by the mean circulation and comparable decrease of upward heat flux by the subgrid-scale processes; the upward eddy heat flux decreases and increases by almost the same magnitude in response to, respectively, the "thermal" and "wind" forcing. Regionally, the surface heat loss and deep convection weaken in the Labrador Sea, but intensify in the Greenland Sea in the region of sea ice retreat. The enhanced heat flux anomaly in the subpolar Atlantic is mainly caused by the "thermal" forcing.

  7. Chemical-Stockpile Disposal Program. Evaluation of multiple-incinerator air-quality impacts, Edgewood Area, Aberdeen Proving Ground. Final report, November 1986-May 1987

    SciTech Connect

    Not Available

    1987-05-01

    The purpose of this study was to examine the long-term additive ambient impact of certain toxic air pollutants that will potentially be emitted from the Chemical Agent Incinerator (AI) proposed for the Edgewood Area (EA) of Aberdeen Proving Ground (APG), Maryland and from three additional planned or existing incinerators also located on the EA. This impact was determined in consideration of the existence and operation of three additional planned or existing incinerators also located on EA. Based on air-dispersion modeling conducted as part of an original analysis, emissions were estimated of chlorinated organics from the U.S. Army Medical Research Institute for Chemical Research, Development and Engineering Center Decontamination/Detoxification Municipal Waste Incinerator (MWI), for downwind distances as great as the distance to the nearest boundary of the EA. Consequently, for this evaluation, only the MWI is considered to emit chlorinated organics.

  8. Gender, airborne chemical monitoring, and physical work environment are related to indoor air symptoms among nonindustrial workers in the Klang Valley, Malaysia

    PubMed Central

    Syazwan, Aizat Ismail; Hafizan, Juahir; Baharudin, Mohd Rafee; Azman, Ahmad Zaid Fattah; Izwyn, Zulkapri; Zulfadhli, Ismail; Syahidatussyakirah, Katis

    2013-01-01

    Objectives: The purpose of this study was to analyze the relationship of airborne chemicals and the physical work environment risk element on the indoor air symptoms of nonindustrial workers. Design: A cross-sectional study consisting of 200 office workers. A random selection of 200 buildings was analyzed for exposure and indoor air symptoms based on a pilot study in the Klang Valley, Malaysia. Methods: A set of modified published questionnaires by the Department of Occupational Safety and Health (DOSH), Malaysia and a previous study (MM040NA questionnaire) pertaining to indoor air symptoms was used in the evaluation process of the indoor air symptoms. Statistical analyses involving logistic regression and linear regression were used to determine the relationship between exposure and indoor air symptoms for use in the development of an indoor risk matrix. Results: The results indicate that some indoor air pollutants (carbon monoxide, formaldehyde, total volatile organic compound, and dust) are related to indoor air symptoms of men and women. Temperature and relative humidity showed a positive association with complaints related to the perceived indoor environmental condition (drafts and inconsistency of temperature). Men predominantly reported general symptoms when stratification of gender involved exposure to formaldehyde. Women reported high levels of complaints related to mucosal and general symptoms from exposure to the dust level indoors. Conclusion: Exposure to pollutants (total volatile organic compounds, carbon monoxide, and formaldehyde) and physical stressors (air temperature and relative humidity) influence reported symptoms of office workers. These parameters should be focused upon and graded as one of the important elements in the grading procedure when qualitatively evaluating the indoor environment. PMID:23526736

  9. MAPPING DISSEMINATION OF CHEMICAL AFTER DISPERSIVE EVENTS USING AN AMBIENT-AIR, SURFACE SAMPLING TIME-OF-FLIGHT MASS SPECTROMETER

    EPA Science Inventory

    Chemicals are dispersed by numerous accidental, deliberate, or weather-related events. Often, rapid analyses are desired to identify dispersed chemicals and to delineate areas of contamination. Hundreds of wipe samples might be collected from outdoor surfaces or building interi...

  10. Theoretical analysis of injecting the compressed air through a defensive well into aquifer aimed to separate between polluted and fresh water

    NASA Astrophysics Data System (ADS)

    Boger, M.; Ravina, I.

    2012-12-01

    Injecting a compressed air, through a well, located between the sea or a polluted lake and fresh ground water, creates a "hydraulic barrier" that prevents their mixing. Steady influx of air to a saturated soil produces a pressure gradient from the well and replacement of water by air, hence the interface between air and water increases. After the compression process is stopped, the soil pores are filled with air, so that saturated soil becomes unsaturated with a decreased conductivity. Creating such a barrier, first by the air pressure and second by blocking of the pores, is welcomed at the interface sea-fresh water area, for example. It prevents the loss of fresh water to the sea and it decreases sea water movement into the aquifer. Another positive effect of the air injection is the air flow through unsaturated zone, above the ground water, that decreases polluted water down-seepage from the surface thus defending the fresh ground water against pollution. The regular water well or special drilled one will be used as defensive well. The radius of defensive well can be smaller than the one of the water well. The explanation of the defensive well exploitation in the field for one and multi layer aquifers is presented. Analytical evaluations of the pressure loss and shape of the air-water interfaces in saturated soil are presented for: (a) steady air flow for a one layer aquifer and for a three layer one (leaky aquifer case), (b) transient air flow for a one layer aquifer. It is shown that the shape of air-water interfaces is generally an inverted cone, where the decrease of air pressure in the aquifer with the distance from the well is approximately logarithmic. The necessary pressure to create the effective air flow in the aquifer is only about tens percent higher than static water pressure in the well.

  11. Novel process of bio-chemical ammonia removal from air streams using a water reflux system and zeolite as filter media.

    PubMed

    Vitzthum von Eckstaedt, Sebastian; Charles, Wipa; Ho, Goen; Cord-Ruwisch, Ralf

    2016-02-01

    A novel biofilter that removes ammonia from air streams and converts it to nitrogen gas has been developed and operated continuously for 300 days. The ammonia from the incoming up-flow air stream is first absorbed into water and the carrier material, zeolite. A continuous gravity reflux of condensed water from the exit of the biofilter provides moisture for nitrifying bacteria to develop and convert dissolved ammonia (ammonium) to nitrite/nitrate. The down-flow of the condensed water reflux washes down nitrite/nitrate preventing ammonium and nitrite/nitrate accumulation at the top region of the biofilter. The evaporation caused by the inflow air leads to the accumulation of nitrite to extremely high concentrations in the bottom of the biofilter. The high nitrite concentrations favour the spontaneous chemical oxidation of ammonium by nitrite to nitrogen (N2). Tests showed that this chemical reaction was catalysed by the zeolite filter medium and allowed it to take place at room temperature. This study shows that ammonia can be removed from air streams and converted to N2 in a fully aerated single step biofilter. The process also overcomes the problem of microorganism-inhibition and resulted in zero leachate production. PMID:26363328

  12. Development of a real-time chemical injection system for air-assisted variable-rate sprayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A chemical injection system is an effective method to minimize chemical waste and reduce the environmental pollution in pesticide spray applications. A microprocessor controlled injection system implementing a ceramic piston metering pump was developed to accurately dispense chemicals to be mixed wi...

  13. Assessment of the MACC reanalysis and its influence as chemical boundary conditions for regional air quality modeling in AQMEII-2

    EPA Science Inventory

    The Air Quality Model Evaluation International Initiative (AQMEII) has now reached its second phase which is dedicated to the evaluation of online coupled chemistry-meteorology models. Sixteen modeling groups from Europe and five from North America have run regional air quality m...

  14. [On the problem of the study of the chemical air pollution with chlororganic hydrocarbons at productions of polyvinyl chloride and epichlorohydrin].

    PubMed

    Taranenko, N A; Meshakova, N M; Zhurba, O M; Telezhkin, V V

    2014-01-01

    Hygienic assessment of working conditions at the chemical productions of polyvinyl chloride (PVC) and epichlorohydrin (EPCH) in East Siberia has shown that the employees are exposed to the chlororganic hydrocarbons of hazard category 1-2, out of them there were found to be more toxical pollutants such as vinyl chloride, 1.2-dicloroethane in the production of polyvinyl chloride; allyl chloride and epichlorohydrin in the production of epichlorohydrin. Multistageness of the technological processes, the absence of the isolation of main stages of the technological processes as well as the heating microclimate contribute to the chemical pollution of the air environment. In spite of the significant improvement of the hygienic situation at the productions mentioned in the recent 10 years according to the chemical factor due to the introduction of the complex of curative measures, the working conditions of the employees still belonged to the harmful category. According to the content of the harmful chemical substances in the air of the working zone and the parameters of microclimate, the working conditions of the employees working at the production of epichlorohydrin and in the shop of vinyl chloride production must be qualified as the harmful ones of the first category of the hazard and danger (Class 3.1), in the production shop for PVC- as the harmful ones which correspond to the second category of the hazard and danger (Class 3.2). PMID:25842495

  15. Weather elements, chemical air pollutants and airborne pollen influencing asthma emergency room visits in Szeged, Hungary: performance of two objective weather classifications

    NASA Astrophysics Data System (ADS)

    Makra, László; Puskás, János; Matyasovszky, István; Csépe, Zoltán; Lelovics, Enikő; Bálint, Beatrix; Tusnády, Gábor

    2015-09-01

    Weather classification approaches may be useful tools in modelling the occurrence of respiratory diseases. The aim of the study is to compare the performance of an objectively defined weather classification and the Spatial Synoptic Classification (SSC) in classifying emergency department (ED) visits for acute asthma depending from weather, air pollutants, and airborne pollen variables for Szeged, Hungary, for the 9-year period 1999-2007. The research is performed for three different pollen-related periods of the year and the annual data set. According to age and gender, nine patient categories, eight meteorological variables, seven chemical air pollutants, and two pollen categories were used. In general, partly dry and cold air and partly warm and humid air aggravate substantially the symptoms of asthmatics. Our major findings are consistent with this establishment. Namely, for the objectively defined weather types favourable conditions for asthma ER visits occur when an anticyclonic ridge weather situation happens with near extreme temperature and humidity parameters. Accordingly, the SSC weather types facilitate aggravating asthmatic conditions if warm or cool weather occur with high humidity in both cases. Favourable conditions for asthma attacks are confirmed in the extreme seasons when atmospheric stability contributes to enrichment of air pollutants. The total efficiency of the two classification approaches is similar in spite of the fact that the methodology for derivation of the individual types within the two classification approaches is completely different.

  16. Weather elements, chemical air pollutants and airborne pollen influencing asthma emergency room visits in Szeged, Hungary: performance of two objective weather classifications.

    PubMed

    Makra, László; Puskás, János; Matyasovszky, István; Csépe, Zoltán; Lelovics, Enikő; Bálint, Beatrix; Tusnády, Gábor

    2015-09-01

    Weather classification approaches may be useful tools in modelling the occurrence of respiratory diseases. The aim of the study is to compare the performance of an objectively defined weather classification and the Spatial Synoptic Classification (SSC) in classifying emergency department (ED) visits for acute asthma depending from weather, air pollutants, and airborne pollen variables for Szeged, Hungary, for the 9-year period 1999-2007. The research is performed for three different pollen-related periods of the year and the annual data set. According to age and gender, nine patient categories, eight meteorological variables, seven chemical air pollutants, and two pollen categories were used. In general, partly dry and cold air and partly warm and humid air aggravate substantially the symptoms of asthmatics. Our major findings are consistent with this establishment. Namely, for the objectively defined weather types favourable conditions for asthma ER visits occur when an anticyclonic ridge weather situation happens with near extreme temperature and humidity parameters. Accordingly, the SSC weather types facilitate aggravating asthmatic conditions if warm or cool weather occur with high humidity in both cases. Favourable conditions for asthma attacks are confirmed in the extreme seasons when atmospheric stability contributes to enrichment of air pollutants. The total efficiency of the two classification approaches is similar in spite of the fact that the methodology for derivation of the individual types within the two classification approaches is completely different. PMID:25504051

  17. Cryogenic molecular separation system for radioactive 11C ion acceleration

    NASA Astrophysics Data System (ADS)

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.

    2015-12-01

    A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  18. Fate of 17β-Estradiol as a model estrogen in source separated urine during integrated chemical P recovery and treatment using partial nitritation-anammox process.

    PubMed

    Huang, Pei; Mukherji, Sachiyo T; Wu, Sha; Muller, James; Goel, Ramesh

    2016-10-15

    Recently, research on source separation followed by the treatment of urine and/or resource recovery from human urine has shown promise as an emerging management strategy. Despite contributing only 1% of the total volume of wastewater, human urine contributes about 80% of the nitrogen, 70% of the potassium, and up to 50% of the total phosphorus in wastewater. It is also a known fact that many of the micropollutants, especially selected estrogens, get into municipal wastewater through urine excretion. In this research, we investigated the fate of 17β-estradiol (E2) as a model estrogen during struvite precipitation from synthetic urine followed by the treatment of urine using a partial nitritation-anammox (PN/A) system. Single-stage and two-stage suspended growth PN/A configurations were used to remove the nitrogen in urine after struvite precipitation. The results showed an almost 95% phosphorous and 5% nitrogen recovery/removal from the synthetic urine due to struvite precipitation. The single and two stage PN/A processes were able to remove around 50% and 75% of ammonia and nitrogen present in the post struvite urine solution, respectively. After struvite precipitation, more than 95% of the E2 remained in solution and the transformation of E2 to E1 happened during urine storage. Most of the E2 removal that occurred during the PN/A process was due to sorption on the biomass and biodegradation (transformation of E2 to E1, and slow degradation of E1 to other metabolites). These results demonstrate that a combination of chemical and biological unit processes will be needed to recover and manage nutrients in source separated urine. PMID:27566951

  19. Quantum chemical approach in the description of the amphiphile clusterization at the air/liquid and liquid/liquid interfaces with phase nature accounting. I. Aliphatic normal alcohols at the air/water interface.

    PubMed

    Vysotsky, Yuri B; Belyaeva, Elena A; Kartashynska, Elena S; Fainerman, Valentine B; Smirnova, Natalia A

    2015-02-19

    A new model based on the quantum chemical approach is proposed to describe structural and thermodynamic parameters of clusterization for substituted alkanes at the air/liquid and liquid/liquid interfaces. The new model by the authors, unlike the previous one, proposes an explicit account of the liquid phase (phases) influence on the parameters of monomers, clusters and monolayers of substituted alkanes at the regarded interface. The calculations were carried out in the frameworks of the quantum chemical semiempirical PM3 method (Mopac 2012), using the COSMO procedure. The new model was tested in the calculations of the clusterization parameters of fatty alcohols under the standard conditions at the air/water interface. The enthalpy, Gibbs' energy and absolute entropy of formation for alcohol monomers alongside with clusterization parameters for the cluster series including the monolayer at air/water interface were calculated. In our calculations the sinkage of monomers, molecules in clusters and monolayers was varied from 1 up to 5 methylene groups. Thermodynamic parameters calculated using the proposed model for the alcohol monolayers are in a good agreement with the corresponding experimental data. However, the proposed model cannot define the most energetically preferable immersion of the monolayer molecules in the water phase. PMID:25640463

  20. Toxic chemical release inventory information.

    PubMed

    Bronson, R J

    1991-01-01

    As part of a U.S. government effort to inform the public about toxic or hazardous chemicals released into the environment, the National Library of Medicine (NLM) and the Environmental Protection Agency (EPA) are jointly producing the TRI (Toxic Chemical Release Inventory) databanks which consist of two separate files, TRI87 and TRI88. Both files reside on NLM's TOX-NET system. The files contain geographic information about reporting facilities and land, air, and water release data for approximately 300 listed chemicals. PMID:10111718

  1. Statistical association between cancer incidence and major-cause mortality, and estimated residential exposure to air emissions from petroleum and chemical plants

    SciTech Connect

    Kaldor, J.; Harris, J.A.; Glazer, E.; Glaser, S.; Neutra, R.; Mayberry, R.; Nelson, V.; Robinson, L.; Reed, D.

    1984-03-01

    An ecologic study design was used to investigate the relationship between exposure to air emissions produced by the petroleum and chemical industries, and average annual cancer incidence and major cause mortality rates among whites in Contra Costa County, California. Estimates for the exposure to major industrial sources of sulfur dioxide, hydrocarbons and oxides of nitrogen were used to subdivide the county by level of exposure to petroleum refinery and chemical plant emissions. Cancer incidence and major cause mortality rates were then calculated for whites in each of the exposure areas. In both males and females, residential exposure to petroleum and chemical air emissions was associated with an increased incidence of cancer of the buccal cavity and pharynx. In males, age-adjusted incidence rates for cancers of the stomach, lung, prostate and kidney and urinary organs were also associated with petroleum and chemical plant air emission exposures. In both sexes, a strong positive association was found between degree of residential exposure and death rates from cardiovascular disease and cancer, and a less strong positive association between exposure and death rates from cerebrovascular disease. There was also a positive association in men for deaths from cirrhosis of the liver. Although these observed associations occurred across areas of similar socioeconomic and broad occupational class, confounding variables and the ecologic fallacy must be considered as possible explanations. In particular, the strong findings in men suggest an occupational explanation of the cancer incidence trends, and the effect observed in cirrhosis mortality suggests that lifestyle variables such as alcohol consumption were not adequately controlled for. 26 references, 1 figure, 6 tables.

  2. Statistical association between cancer incidence and major-cause mortality, and estimated residential exposure to air emissions from petroleum and chemical plants.

    PubMed Central

    Kaldor, J; Harris, J A; Glazer, E; Glaser, S; Neutra, R; Mayberry, R; Nelson, V; Robinson, L; Reed, D

    1984-01-01

    An ecologic study design was used to investigate the relationship between exposure to air emissions produced by the petroleum and chemical industries, and average annual cancer incidence and major cause mortality rates among whites in Contra Costa County, California. Estimates for the exposure to major industrial sources of sulfur dioxide, hydrocarbons and oxides of nitrogen were used to subdivide the county by level of exposure to petroleum refinery and chemical plant emissions. Cancer incidence and major cause mortality rates were then calculated for whites in each of the exposure areas. In both males and females, residential exposure to petroleum and chemical air emissions was associated with an increased incidence of cancer of the buccal cavity and pharynx. In males, age-adjusted incidence rates for cancers of the stomach, lung, prostate and kidney and urinary organs were also associated with petroleum and chemical plant air emission exposures. In both sexes, we found a strong positive association between degree of residential exposure and death rates from cardiovascular disease and cancer, and a less strong positive association between exposure and death rates from cerebrovascular disease. There was also a positive association in men for deaths from cirrhosis of the liver. Although these observed associations occurred across areas of similar socioeconomic and broad occupational class, confounding variables and the "ecologic fallacy" must be considered as possible explanations. In particular, the stronger findings in men suggest an occupational explanation of the cancer incidence trends, and the effect observed in cirrhosis mortality suggests that lifestyle variables such as alcohol consumption were not adequately controlled for. While the public health implications of our findings remain unclear, the evidence presented is sufficient to warrant follow-up studies based on individual data in which possible biases can be more readily controlled. PMID:6734567

  3. Time-dependent chemical compositions of 13N and 15O induced in air by the operation of a high energy electron accelerator.

    PubMed

    Endo, A; Henshaw, J; Mignanelli, M A

    1998-04-01

    Time-dependent chemical compositions for 13N and 15O induced in the air atmosphere of a high energy electron accelerator room have been studied using a computer simulation method. A radiation chemistry model was developed to describe the chemical reactions of 13N and 15O species with the air molecules and their radiolytic products. By assuming several chemical forms of 13N and 15O generated by the (gamma, n) reaction, the variations of the concentrations of 13N and 15O species were simulated under a radiation field. From the comparison between the simulations and experiment in a 100 MeV electron linear accelerator (linac) facility, the following conclusions were obtained: (1) Just after the (gamma, n) reaction, 25-50% of 13N and 15O are present as atoms (13N, 15O) and/or their ions (13N+, 15O+) and the remainder as nitrogen and oxygen molecules (13NN, 15OO) and/or their ions (13NN+, 15OO+); (2) Neutralization of 13N+ and 15O+ ions into 13N and 15O atoms occurs instantaneously and the same is the case with the neutralization of 13NN+ and 15OO+ ions to 13NN and 15OO molecules; (3) The neutralized 13N and 15O atoms react with the air molecules and the radiolytic products to form nitrogen oxide compounds and ozone, while 13NN and 15OO remain as these molecules. Factors that control the chemical reactions of 13N and 15O are discussed. PMID:9525420

  4. Determination of Os by isotope dilution-inductively coupled plasma-mass spectrometry with the combination of laser ablation to introduce chemically separated geological samples

    NASA Astrophysics Data System (ADS)

    Sun, Yali; Ren, Minghao; Xia, Xiaoping; Li, Congying; Sun, Weidong

    2015-11-01

    A method was developed for the determination of trace Os in geological samples by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) with the combination of chemical separation and preconcentration. Samples are digested using aqua regia in Carius tubes, and the Os analyte is converted into volatile OsO4, which is distilled and absorbed with HBr. The HBr solution is concentrated for further Os purification using the microdistillation technique. The purified Os is dissolved in 10 μl of 0.02% sucrose-0.005% H3PO4 solution and then evaporated on pieces of perfluoroalkoxy (PFA) film, resulting in the formation of a tiny object (< 3 × 104 μm2 superficial area). Using LA-ICP-MS measurements, the object can give Os signals at least 100 times higher than those provided by routine solution-ICP-MS while successfully avoiding the memory effect. The procedural blank and detection limit in the developed technique are 3.0 pg and 1.8 pg for Os, respectively when 1 g of samples is taken. Reference materials (RM) are analyzed, and their Os concentrations obtained by isotope dilution are comparable to reference or literature values. Based on the individual RM results, the precision is estimated within the range of 0.6 to 9.4% relative standard deviation (RSD), revealing that this method is applicable to the determination of trace Os in geological samples.

  5. Chemical separation and mass spectrometry of Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial materials using thermal ionization mass spectrometry.

    PubMed

    Yamakawa, Akane; Yamashita, Katsuyuki; Makishima, Akio; Nakamura, Eizo

    2009-12-01

    A sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks was developed for precise and accurate determination of elemental concentration by the isotope dilution method (ID). The technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The method was tested using a variety of matrixes including bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-1b). Concentrations of each element was determined by thermal ionization mass spectrometry (TIMS) using W filaments and a Si-B-Al type activator for Cr, Fe, Ni, and Zn and a Re filament and silicic acid-H3PO4 activator for Cu. The method can be used to precisely determine the concentrations of these elements in very small silicate samples, including meteorites, geochemical reference samples, and mineral standards for microprobe analysis. Furthermore, the Cr mass spectrometry procedure developed in this study can be extended to determine the isotopic ratios of 53Cr/52Cr and 54Cr/52Cr with precision of approximately 0.05epsilon and approximately 0.10epsilon (1epsilon = 0.01%), respectively, enabling cosmochemical applications such as high precision Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites. PMID:19886654

  6. Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities.

    PubMed

    Hoskins, Daniel L; Zhang, Xiaoyuan; Hickner, Michael A; Logan, Bruce E

    2014-11-01

    Separators are used to protect cathodes from biofouling and to avoid electrode short-circuiting, but they can adversely affect microbial fuel cell (MFC) performance. A spray method was used to apply a polyvinyl alcohol (PVA) separator to the cathode. Power densities were unaffected by the PVA separator (339±29mW/m(2)), compared to a control lacking a separator in a low conductivity solution (1mS/cm) similar to wastewater. Power was reduced with separators in solutions typical of laboratory tests (7-13mS/cm), compared to separatorless controls. The PVA separator produced more power in a separator assembly (SEA) configuration (444±8mW/m(2)) in the 1mS/cm solution, but power was reduced if a PVA or wipe separator was used in higher conductivity solutions with either Pt or activated carbon catalysts. Spray and cast PVA separators performed similarly, but the spray method is preferred as it was easier to apply and use. PMID:25260178

  7. An improved high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry method for determination of chlorophylls and their derivatives in freeze-dried and hot-air-dried Rhinacanthus nasutus (L.) Kurz.

    PubMed

    Kao, Tsai Hua; Chen, Chia Ju; Chen, Bing Huei

    2011-10-30

    Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated. PMID:22063550

  8. Task 38 - commercial mercury remediation demonstrations: Thermal retorting and physical separation/chemical leaching. Topical report, December 1, 1994--June 30, 1996

    SciTech Connect

    Charlton, D.S.; Fraley, R.H.; Stepan, D.J.

    1998-12-31

    Results are presented on the demonstration of two commercial technologies for the removal of mercury from soils found at natural gas metering sites. Technologies include a thermal retorting process and a combination of separation, leaching, and electrokinetic separation process.

  9. A review of reaction rates and thermodynamic and transport properties for an 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.; Lee, Kam-Pui

    1990-01-01

    Reaction rate coefficients and thermodynamic and transport properties are reviewed and supplemented for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium up to temperatures of 3000 K. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Curve fits are given for the various species properties for their efficient computation in flowfield codes. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in a high energy environment. Limitations of the approximate mixing laws are discussed for a mixture of ionized species. An electron number-density correction for the transport properties of the charged species is obtained. This correction has been generally ignored in the literature.

  10. Thermal-Hydraulic Analysis of an Experimental Reactor Cavity Cooling System with Air. Part I: Experiments; Part II: Separate Effects Tests and Modeling

    SciTech Connect

    Corradin, Michael; Anderson, M.; Muci, M.; Hassan, Yassin; Dominguez, A.; Tokuhiro, Akira; Hamman, K.

    2014-10-15

    This experimental study investigates the thermal hydraulic behavior and the heat removal performance for a scaled Reactor Cavity Cooling System (RCCS) with air. A quarter-scale RCCS facility was designed and built based on a full-scale General Atomics (GA) RCCS design concept for the Modular High Temperature Gas Reactor (MHTGR). The GA RCCS is a passive cooling system that draws in air to use as the cooling fluid to remove heat radiated from the reactor pressure vessel to the air-cooled riser tubes and discharged the heated air into the atmosphere. Scaling laws were used to preserve key aspects and to maintain similarity. The scaled air RCCS facility at UW-Madison is a quarter-scale reduced length experiment housing six riser ducts that represent a 9.5° sector slice of the full-scale GA air RCCS concept. Radiant heaters were used to simulate the heat radiation from the reactor pressure vessel. The maximum power that can be achieved with the radiant heaters is 40 kW with a peak heat flux of 25 kW per meter squared. The quarter-scale RCCS was run under different heat loading cases and operated successfully. Instabilities were observed in some experiments in which one of the two exhaust ducts experienced a flow reversal for a period of time. The data and analysis presented show that the RCCS has promising potential to be a decay heat removal system during an accident scenario.

  11. DESIGN AND CHARACTERIZATION OF A SMALL CHAMBER FOR CHEMICAL AND BIOLOGICAL EVALUATION OF SOURCES OF INDOOR AIR CONTAMINATION

    EPA Science Inventory

    The paper discusses exposure generation considerations prior to implementation of sensory irritation bioassays for product emissions. mall chambers are used to generate source emissions from products for chemical and biological evaluation. esign of the source emissions chamber an...

  12. Chemical microsensors

    DOEpatents

    Li, DeQuan; Swanson, Basil I.

    1995-01-01

    An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

  13. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    NASA Technical Reports Server (NTRS)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  14. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rates

    EPA Science Inventory

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions....

  15. Separation and determination of diversiform phytosterols in food materials using supercritical carbon dioxide extraction and ultraperformance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    Lu, Baiyi; Zhang, Ying; Wu, Xiaoqin; Shi, Jiayi

    2007-04-01

    This paper presents at first time that the ultra-performance liquid chromatographic atmospheric pressure chemical ionization mass spectrometer (UPLC-APCI-MS) was used as an efficient method for the identification and quantification of diversiform phytosterols in food materials. The sample preparation consisted of extraction by supercritical carbon dioxide fluid extraction (SCE) and saponification by refluxing with ethanolic KOH, and then the non-saponificable fraction was extracted with petroleum ether. This fraction was subjected to solid phase extraction (SPE) on silica gel cartridge and then the sterols were eluted with hexane-ethyl acetate. Sterols were separated on an Acquity UPLC BEH C18 column (100 mm x 1.0 mm, 1.7 microm particle size) with a gradient of methanol/water (1% acetonitrile) at a flow of 0.1 mL min(-1). The determination was performed in selective ion monitoring mode. The quality parameter of the developed method was established using 6-ketocholestanol as internal standard. Limits of quantification (LOQ) were 0.1754, 0.0341, 0.0500, 0.0205, 0.0225, 0.3674, 0.0241, 0.0272, 0.0076 microg L(-1) and 0.1525 microg mL(-1) for 6-ketocholestanol, desmosterol, ergosterol, cholesterol, lanosterol, cholestanol, campesterol, stigmasterol, beta-sitosterol, and stigmastanol, respectively. The intra- and inter-day determination precision for the 10 phytosterols were less than 5 and 6% in relative standard deviations, and their recoveries were located in the range of 94-107%. The developed approach has been applied successfully for efficient determination of diversiform phytosterols in food materials, including corn, sesame, oat and peanut. PMID:17386793

  16. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    NASA Astrophysics Data System (ADS)

    Foley, Theresa

    The Clean Air Act of 1970 was promulgated after thousands of lives were lost in four catastrophic air pollution events. It authorized the establishment of National Ambient Air Quality Standards or (NAAQS) for six pollutants that are harmful to human health and welfare: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone and sulfur dioxide. The Clean Air Act also led to the establishment of the United Stated Environmental Protection Agency (US EPA) to set and enforce regulations. The first paper in this dissertation studies ozone in the Lake Michigan region (Foley, T., Betterton, E.A., Jacko, R., Hillery, J., 2011. Lake Michigan air quality: The 1994-2003 LADCO Aircraft Project (LAP). Atmospheric Environment 45, 3192-3202.) The Chicago-Milwaukee-Gary metropolitan area has been unable to meet the ozone NAAQS since the Clean Air Act was implemented. The Lake Michigan Air Directors' Consortium (LADCO) hypothesized that land breezes transport ozone precursor compounds over the lake, where a large air/water temperature difference creates a shallow conduction layer, which is an efficient reaction chamber for ozone formation. In the afternoon, lake breezes and prevailing synoptic winds then transport ozone back over the land. To further evaluate this hypothesis, LADCO sponsored the 1994-2003 LADCO Aircraft Project (LAP) to measure the air quality over Lake Michigan and the surrounding areas. This study has found that the LAP data supports this hypothesis of ozone formation, which has strong implications for ozone control strategies in the Lake Michigan region. The second paper is this dissertation (Foley, T., Betterton, E.A., Wolf, A.M.A., 2012. Ambient PM10 and metal concentrations measured in the Sunnyside Unified School District, Tucson, Arizona. Journal of the Arizona-Nevada Academy of Science, 43, 67-76) evaluated the airborne concentrations of PM10 (particulate matter with an aerodynamic diameter of 10 microns or less) and eight metalloids and metals

  17. Coupling passive air sampling with emission estimates and chemical fate modeling for persistent organic pollutants (POPs): a feasibility study for Northern Europe.

    PubMed

    Gioia, Rosalinda; Sweetman, Andy J; Jones, Kevin C

    2007-04-01

    Passive air samplers (polyurethane foam disks) were deployed at 23 background locations along a broadly west-east transect in 8 northern European countries and analyzed for PCBs, PBDEs, PAHs, and a range of organochlorine pesticides (HCB, DDTs, and DDEs). PCBs and PAHs were highest at the center of the transect (Denmark) and lowest in northern Norway. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher DDE and DDT levels occurred in Eastern Europe and at several sites in Central Europe. PBDE levels were generally similar at all sites, but lower for some locations in Eastern Europe and Ireland. Emissions information for PCBs, HCB, and PBDEs was used as input for a multi-media chemical fate model, to generate predicted air concentrations and compare with these measured values. Different scenarios were highlighted by this exercise: (i) country and compound combinations where the national inventory gave predicted air concentrations in close agreement with those measured (e.g., PCBs in the UK); (ii) country and compound combinations where predicted concentrations were well below those measured, but where advection of emissions from elsewhere is likely to be important (e.g., PCBs in Norway); (iii) consistent underestimation of compound concentrations by the emissions modeling (i.e., HCB); and (iv) general overestimation of ambient concentrations (i.e., PBDEs). Air mass trajectory analysis showed the likely role of long-range atmospheric transport (LRAT) on national levels. In general, advection from the south and west of Europe appeared to contribute to ambient POPs levels for countries in the center and northeast of the transect. Guidelines are presented as to how countries that want to assess their POPs source inventories can do so with this relatively cheap initial screening approach. PMID:17438758

  18. Mass Separation by Metamaterials

    PubMed Central

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2016-01-01

    Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices. PMID:26912419

  19. Mass Separation by Metamaterials.

    PubMed

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2016-01-01

    Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices. PMID:26912419

  20. Mass Separation by Metamaterials

    NASA Astrophysics Data System (ADS)

    Restrepo-Flórez, Juan Manuel; Maldovan, Martin

    2016-02-01

    Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices.

  1. Impact of chemical and meteorological boundary and initial conditions on air quality modeling: WRF-Chem sensitivity evaluation for a European domain

    NASA Astrophysics Data System (ADS)

    Ritter, Mathias; Müller, Mathias D.; Jorba, Oriol; Parlow, Eberhard; Liu, L.-J. Sally

    2013-01-01

    This study evaluates the impact of different chemical and meteorological boundary and initial conditions on the state-of-the-art Weather Research and Forecasting (WRF) model with its chemistry extension (WRF-Chem). The evaluation is done for July 2005 with 50 km horizontal resolution. The effect of monthly mean chemical boundary conditions derived from the chemical transport model LMDZ-INCA on WRF-Chem is evaluated against the effect of the preset idealized profiles. Likewise, the impact of different meteorological initial and boundary conditions (GFS and Reanalysis II) on the model is evaluated. Pearson correlation coefficient between these different runs range from 0.96 to 1.00. Exceptions exists for chemical boundary conditions on ozone and for meteorological boundary conditions on PM10, where coefficients of 0.90 were obtained. Best results were achieved with boundary and initial conditions from LMDZ-INCA and GFS. Overall, the European simulations show encouraging results for observed air pollutant, with ozone being the most and PM10 being the least satisfying.

  2. Polycyclic organic material (POM) in urban air. Fractionation, chemical analysis and genotoxicity of particulate and vapour phases in an industrial town in Finland

    NASA Astrophysics Data System (ADS)

    Pyysalo, Heikki; Tuominen, Jari; Wickström, Kim; Skyttä, Eija; Tikkanen, Leena; Salomaa, Sisko; Sorsa, Marja; Nurmela, Tuomo; Mattila, Tiina; Pohjola, Veijo

    Polycyclic organic material (POM) was collected by high-volume sampling on filter and on XAD-2 resin from the air of a small industrial town in Finland. Concurrent chemical analysis and the assays for genotoxic activity were performed on the particulate and the vapour phases of ambient air POM and their chemical fractions. Furthermore, correlations between seasonal meteorological parameters and POM concentrations were studied to reveal characteristic POM profiles for various emission sources. The range of total POM concentrations varied from 115 to 380 ng m -3 in late spring and from 17 to 83 ng m -3 in early winter. No direct correlation of ambient POM was seen with the temperature, but rather with the wind direction from various emission sources. Especially the low molecular weight compounds were associated with wind direction from industrial sources. Genotoxic activity, as detected by the Ames Salmonella/microsome test and the SCE assay in CHO cells, was found not only in the paniculate phase samples but also in the vapour phase. The polar fractions of some of the samples showed genotoxic activity, and also direct mutagenicity was observed with both the assay systems; these facts support the significance of compounds other than conventional polycyclic aromatic hydrocarbons (PAH) in the samples.

  3. A NEW NON-DESTRUCTIVE METHOD FOR CHEMICAL ANALYSIS OF PARTICULATE MATTER FILTERS: THE CASE OF MANGANESE AIR POLLUTION IN VALLECAMONICA (ITALY)

    PubMed Central

    Borgese, Laura; Zacco, Annalisa; Pal, Sudipto; Bontempi, Elza; Lucchini, Roberto; Zimmerman, Neil; Depero, Laura E.

    2011-01-01

    Total Reflection X-ray Fluorescence (TXRF) is a well-established technique for chemical analysis, but it is mainly employed for quality control in the electronics semiconductor industry. The capability to analyze liquid and uniformly thin solid samples makes this technique suitable for other applications, and especially in the very critical field of environmental analysis. Comparison with standard methods like Inductively Coupled Plasma (ICP) and Atomic Absorption Spectroscopy (AAS) show that TXRF is a practical, accurate, and reliable technique in occupational settings. Due to the greater sensitivity necessary in trace heavy metal detection, TXRF is also suitable for environmental chemical analysis. In this paper we show that based on appropriate standards, TXRF can be considered for non-destructive routine quantitative analysis of environmental matrices such as air filters. This work has been developed in the frame of the EU-FP6 PHIME (Public Health Impact of long-term, low-level Mixed element Exposure in susceptible population strata) Integrated Project (www.phime.org). The aim of this work was to investigate Mn air pollution in the area of Vallecamonica (Italy). PMID:21315919

  4. Using a glass fiber separator in a single-chamber air-cathode microbial fuel cell shortens start-up time and improves anode performance at ambient and mesophilic temperatures.

    PubMed

    Zhang, Xiaoyuan; Liang, Peng; Shi, Juan; Wei, Jincheng; Huang, Xia

    2013-02-01

    A shorter start-up time and highly negative anode potentials are needed to improve single-chamber air-cathode microbial fuel cells (MFCs). Using a glass fiber separator reduced the start-up time from 10d to 8d at 20°C, and from 4d to 2d at 30°C, and enhanced coulombic efficiency (CE) from <60% to 89% (20°C) and 87% (30°C). Separators also reduced anode potentials by 20-190mV, charge transfer resistances by 76% (20°C) and 19% (30°C), and increased CV peak currents by 24% (20°C) and 8% (30°C) and the potential range for redox activity (-0.55 to 0.10mV vs. -0.49 to -0.24mV at 20°C). Using a glass fiber separator in an air-cathode MFC, combined with inoculation at a mesophilic temperature, are excellent strategies to shorten start-up time and to enhance anode performance and CE. PMID:23334007

  5. Simulating Emission and Chemical Evolution of Coarse Sea-Salt Particles in the Community Multiscale Air Quality (CMAQ) Model

    EPA Science Inventory

    Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-sal...

  6. USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS

    EPA Science Inventory

    Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...

  7. Dimensionality estimate of the manifold in chemical composition space for a turbulent premixed H2+air flame

    SciTech Connect

    Tonse, Shaheen R.; Brown, Nancy J.

    2003-02-26

    The dimensionality (D) of manifolds of active chemical composition space has been measured using three different approaches: the Hausdorff geometrical binning method, Principal Component Analysis, and the Grassberger-Procaccia cumulative distribution method. A series of artificial manifolds is also generated using a Monte Carlo approach to discern the advantages and limitations of the three methods. Dimensionality is quantified for different levels of turbulent intensity in a simulation of the interactions of a 2D premixed hydrogen flame with a localized region of turbulence superimposed over the cold region upstream of the flame front. The simulations are conducted using an adaptive mesh refinement code for low Mach number reacting flows. By treating the N{sub s} species and temperature of the local thermo-chemical state as a point in multi-dimensional chemical composition space, a snapshot of a flame region is mapped into chemical composition space to generate the manifold associated with the 2-D flame system. An increase in D was observed with increasing turbulent intensity for all three methods. Although each method provides useful information, the Grassberger-Procaccia method is subject to fewer artifacts than the other two thereby providing the most reliable quantification of D.

  8. Chemical mass balance modeling for air quality analysis near a waste-to-energy facility in a complex urban area: Program design

    SciTech Connect

    Wells, R.; Watson, J.; Woy, J. van

    1997-12-31

    This paper describes the design and implementation of an ambient monitoring and receptor modeling study to evaluate air quality impacts from a state-of-the-art municipal waste management facility in a major urban area. The Robbins Resource Recovery Facility (RRRF), located in the Chicago metropolitan area, processes municipal solid waste (MSW) to recover recyclables, process the residual waste to create refuse-derived fuel (RDF), and burns the RDF to reduce the residual waste volume and recover energy. The RRRF is cooperating with the Illinois Environmental Protection Agency (IEPA) and the Illinois Office of the Attorney General (OAG) to analyze air quality and facility impacts in the plant vicinity. An ambient monitoring program began one year before plant operation and will continue for five years after startup. Because the impacts of the RRRF are projected to be very low, and because the Chicago area includes a complex mix of existing industrial, commercial, and residential activity, the ambient data will be analyzed using Version 7.0 of the USEPA s Chemical Mass Balance (CMB) model to estimate the extent of the RRRF`s impact on air quality in the area. The first year of pre-operational ambient data is currently under analysis. This paper describes the study design considerations, ambient monitoring program, emission data acquisition, background source data needs, and data analysis procedures developed to conduct CMB modeling in a complex industrialized area.

  9. Novel chamber to measure equilibrium soil-air partitioning coefficients of low-volatility organic chemicals under conditions of varying temperature and soil moisture.

    PubMed

    Wolters, André; Linnemann, Volker; Smith, Kilian E C; Klingelmann, Eva; Park, Byung-Jun; Vereecken, Harry

    2008-07-01

    The need to determine soil-air partitioning coefficients (K(SA)) of low-volatility organic chemicals as a measure of their distribution in the soil surface after release into the environment resulted in the development of a novel chamber system, which has been filed for patent. A major advantage of this pseudo-static system is that sufficient time can be factored into the experiment to ensure that the system has achieved equilibrium. In a highly precise method, the air is collected in adsorption tubes and subsequently liberated in a thermodesorption system for the quantitation of the adsorbed compound. The precision of the method is great enough that even the effects of temperature and soil moisture on the soil-air partitioning of very low-volatility compounds can be quantified. Because of analytical detection limits, quantitation of these influences has not been possible to date. Functionality of the setup was illustrated by measurements on the fungicide fenpropimorph. K(SA) values of fenpropimorph displayed a negative relationship with temperature and soil moisture. The type of application (spraying or incorporation) and the use of formulated compounds was shown to have a major impact on the measured K(SA) values. Comparison with calculations using an estimation method revealed that the use of experimentally determined K(SA) values will facilitate a more adequate consideration of volatilization in recent model approaches. PMID:18678019

  10. Chemical composition of pre-monsoon air in the Indo-Gangetic Plain measured using a new PTR-MS and air quality facility: high surface ozone and strong influence of biomass burning

    NASA Astrophysics Data System (ADS)

    Sinha, V.; Kumar, V.; Sarkar, C.

    2013-12-01

    One seventh of the world population lives in the Indo-Gangetic Plain (IGP) and the fertile region sustains agricultural food crop production for much of South Asia. Yet it remains one of the most under-studied regions of the world in terms of atmospheric composition and chemistry. In particular, the emissions and chemistry of volatile organic compounds (VOCs) that form surface ozone and secondary organic aerosol through photochemical reactions involving nitrogen oxides is not well understood. In this study, ambient levels of VOCs such as methanol, acetone, acetaldehyde, acetonitrile and isoprene were measured for the first time in the IGP. A new atmospheric chemistry facility that combines India's first high sensitivity proton transfer reaction mass spectrometer, an ambient air quality station and meteorological station, was used to quantify in-situ levels of several VOCs and air pollutants in May 2012 at a suburban site in Mohali (N. W. IGP). Westerly winds arriving at high wind speeds (5-20 m s-1) in the pre-monsoon season at the site, were conducive for chemical characterization of regional emission signatures. Average levels of VOCs and air pollutants in May 2012 ranged from 1.2-1.7 nmol mol-1 for aromatic VOCs, 5.9-37.4 nmol mol-1 for the oxygenated VOCs, 1.4 nmol mol-1 for acetonitrile, 1.9 nmol mol-1 for isoprene, 567 nmol mol-1 for carbon monoxide, 57.8 nmol mol-1 for ozone, 11.5 nmol mol-1 for nitrogen oxides, 7.3 nmol mol-1 for sulphur dioxide, 104 μg m-3 for PM2.5 and 276 μg m-3 for PM10. By analyzing the one minute in-situ data with meteorological parameters and applying chemical tracers (e.g. acetonitrile for biomass burning) and inter-VOC correlations, we were able to constrain major emission source activities on both temporal and diel scales. Wheat residue burning activity caused massive increases (> 3 times of baseline values) for all the measured VOCs and primary pollutants. Other forms of biomass burning at night were also a significant source

  11. Chemical composition of pre-monsoon air in the Indo-Gangetic Plain measured using a new air quality facility and PTR-MS: high surface ozone and strong influence of biomass burning

    NASA Astrophysics Data System (ADS)

    Sinha, V.; Kumar, V.; Sarkar, C.

    2014-06-01

    One seventh of the world's population lives in the Indo-Gangetic Plain (IGP) and the fertile region sustains agricultural food crop production for much of South Asia, yet it remains one of the most under-studied regions of the world in terms of atmospheric composition and chemistry. In particular, the emissions and chemistry of volatile organic compounds (VOCs) that form surface ozone and secondary organic aerosol through photochemical reactions involving nitrogen oxides are not well understood. In this study, ambient levels of VOCs such as methanol, acetone, acetaldehyde, acetonitrile and isoprene were measured for the first time in the IGP. A new atmospheric chemistry facility that combines India's first high-sensitivity proton transfer reaction mass spectrometer, an ambient air quality station and a meteorological station, was used to quantify in situ levels of several VOCs and air pollutants in May 2012 at a suburban site in Mohali (northwest IGP). Westerly winds arriving at high wind speeds (5-20 m s-1) in the pre-monsoon season at the site were conducive for chemical characterization of regional emission signatures. Average levels of VOCs and air pollutants in May~2012 ranged from 1.2 to 2.7 nmol mol-1 for aromatic VOCs, 5.9 to 37.5 nmol mol-1 for the oxygenated VOCs, 1.4 nmol mol-1 for acetonitrile, 1.9 nmol mol-1 for isoprene, 567 nmol mol-1 for carbon monoxide, 57.8 nmol mol-1 for ozone, 11.5 nmol mol-1 for nitrogen oxides, 7.3 nmol mol-1 for sulfur dioxide, 104 μg m-3 for PM2.5 and 276 μg m-3 for PM10. By analyzing the one-minute in situ data with meteorological parameters and applying chemical tracers (e.g., acetonitrile for biomass burning) and inter-VOC correlations, we were able to constrain major emission source activities on both temporal and diel scales. Wheat residue burning caused massive increases (> 3 times the baseline values) for all the measured VOCs and primary pollutants. Other forms of biomass burning at night were also a significant

  12. PM2.5 chemical composition at a rural background site in Central Europe, including correlation and air mass back trajectory analysis

    NASA Astrophysics Data System (ADS)

    Schwarz, Jaroslav; Cusack, Michael; Karban, Jindřich; Chalupníčková, Eva; Havránek, Vladimír; Smolík, Jiří; Ždímal, Vladimír

    2016-07-01

    of fresh, local aerosol and aged, long-range transport aerosol. The influences of different air masses were also investigated. The lowest concentrations of PM2.5 were recorded under the influence of marine air masses from the NW, which were also marked by increased concentrations of marine aerosol. In contrast, the highest concentrations of PM2.5 and most major chemical components were measured during periods when continental easterly air masses were dominant.

  13. Design of Laser Based Monitoring Systems for Compliance Management of Odorous and Hazardous Air Pollutants in Selected Chemical Industrial Estates at Hyderabad, India

    NASA Astrophysics Data System (ADS)

    Sudhakar, P.; Kalavathi, P.; Ramakrishna Rao, D.; Satyanarayna, M.

    2014-12-01

    Industrialization can no longer sustain without internalization of the concerns of the receiving environment and land-use. Increased awareness and public pressure, coupled with regulatory instruments and bodies exert constant pressure on industries to control their emissions to a level acceptable to the receiving environment. However, when a group of industries come-up together as an industrial estate, the cumulative impacts of all the industries together often challenges the expected/desired quality of receiving environment, requiring stringent pollution control and monitoring measures. Laser remote sensing techniques provide powerful tools for environmental monitoring. These methods provide range resolved measurements of concentrations of various gaseous pollutants and suspended particulate matter (SPM) not only in the path of the beam but over the entire area. A three dimensional mapping of the pollutants and their dispersal can be estimated using the laser remote sensing methods on a continuous basis. Laser Radar (Lidar) systems are the measurements technology used in the laser remote sensing methods. Differential absorption lidar (DIAL) and Raman Lidar technologies have proved to be very useful for remote sensing of air pollutants. DIAL and Raman lidar systems can be applied for range resolved measurements of molecules like SO2, NO2, O3 Hg, CO, C2H4, H2O, CH4, hydrocarbons etc. in real time on a continuous basis. This paper describes the design details of the DAIL and Raman lidar techniques for measurement of various hazardous air pollutants which are being released into the atmosphere by the chemical industries operating in the Bachupally industrial Estate area at Hyderabad, India. The relative merits of the two techniques have been studied and the minimum concentration of pollutants that can be measured using these systems are presented. A dispersion model of the air pollutants in the selected chemical industrial estates at Hyderabad has been developed.

  14. A Synergistic Combination of Advanced Separation and Chemical Scale Inhibitor Technologies for Efficient Use of Imparied Water As Cooling Water in Coal-based Power Plants

    SciTech Connect

    Jasbir Gill

    2010-08-30

    Nalco Company is partnering with Argonne National Laboratory (ANL) in this project to jointly develop advanced scale control technologies that will provide cost-effective solutions for coal-based power plants to operate recirculating cooling water systems at high cycles using impaired waters. The overall approach is to use combinations of novel membrane separations and scale inhibitor technologies that will work synergistically, with membrane separations reducing the scaling potential of the cooling water and scale inhibitors extending the safe operating range of the cooling water system. The project started on March 31, 2006 and ended in August 30, 2010. The project was a multiyear, multi-phase project with laboratory research and development as well as a small pilot-scale field demonstration. In Phase 1 (Technical Targets and Proof of Concept), the objectives were to establish quantitative technical targets and develop calcite and silica scale inhibitor chemistries for high stress conditions. Additional Phase I work included bench-scale testing to determine the feasibility of two membrane separation technologies (electrodialysis ED and electrode-ionization EDI) for scale minimization. In Phase 2 (Technology Development and Integration), the objectives were to develop additional novel scale inhibitor chemistries, develop selected separation processes, and optimize the integration of the technology components at the laboratory scale. Phase 3 (Technology Validation) validated the integrated system's performance with a pilot-scale demonstration. During Phase 1, Initial evaluations of impaired water characteristics focused on produced waters and reclaimed municipal wastewater effluents. Literature and new data were collected and evaluated. Characteristics of produced waters vary significantly from one site to another, whereas reclaimed municipal wastewater effluents have relatively more uniform characteristics. Assessment to date confirmed that calcite and silica

  15. [Relationship of the ambient air concentrations of chemical substances to the spread of allergic diseases in children].

    PubMed

    Galeev, K A; Khakimova, R F

    2002-01-01

    The role of some ingredients that contaminate the ambient air in the occurrence and development of allergic diseases was studied. The closest relationships were found between the concentrations of hydrogen sulfide and the prevalence of eczema (rxy +/- m = 0.48 +/- 0.15). There was a direct correlation between the concentrations of each ingredient and the incidence of neurodermitis among children. The correlation between the summarized concentrations of ingredients and the incidence of bronchial asthma among children was rxy +/- m = 0.71 +/- 0.19. The findings serves as the basis for elaborating measures to reduce ecological tension and the incidence of allergic diseases in children. PMID:12380496

  16. Design and characterization of a small chamber for chemical and biological evaluation of sources of indoor air contamination

    SciTech Connect

    Mason, M.A.; Roache, N.F.; Guo, Z.; Costa, D.

    1996-12-31

    The potential for emissions from materials used indoors to cause sensory irritation has prompted several researchers to adapt the mouse bioassay, ASTM E 981, for evaluation of irritancy potential of product emissions.Standardized test procedures that produce comparable results are needed if bioassays, such as ASTM E 981, are to be used to rank and compare products based upon the irritation potential of product emissions. The authors designed, constructed, and determined performance characteristics for a 34-L source emissions chamber, which mates directly to the 2.3-L mouse exposure chamber specified by ASTM E 981 and found the glass chamber to be without significant air leaks and background emissions. Reversible adsorption of decane and p-dichlorobenzene was noted. They found it necessary to add a circulation fan inside the chamber to create air velocities that are representative of those found in indoor environments. The well controlled thermal environment and straightforward connection of the chamber to the mouse exposure chamber used in ASTM E 981 are features that may make this chamber useful in development and evaluation of protocols for biological characterization of product emissions.

  17. Effect of chemically modified Vulcan XC-72R on the performance of air-breathing cathode in a single-chamber microbial fuel cell.

    PubMed

    Duteanu, N; Erable, B; Senthil Kumar, S M; Ghangrekar, M M; Scott, K

    2010-07-01

    The catalytic activity of modified carbon powder (Vulcan XC-72R) for oxygen reduction reaction (ORR) in an air-breathing cathode of a microbial fuel cell (MFC) has been investigated. Chemical modification was carried out by using various chemicals, namely 5% nitric acid, 0.2N phosphoric acid, 0.2N potassium hydroxide and 10% hydrogen peroxide. Electrochemical study was performed for ORR of these modified carbon materials in the buffer solution pH range of 6-7.5 in the anodic compartment. Although, these treatments influenced the surface properties of the carbon material, as evident from the SEM-EDX analysis, treatment with H(2)PO(4), KOH, and H(2)O(2) did not show significant activity during the electrochemical test. The HNO(3) treated Vulcan demonstrated significant ORR activity and when used in the single-chamber MFC cathode, current densities (1115mA/m(2), at 5.6mV) greater than those for a Pt-supported un-treated carbon cathode were achieved. However, the power density for the latter was higher. Such chemically modified carbon material can be a cheaper alternative for expensive platinum catalyst used in MFC cathode construction. PMID:20171090

  18. Ultracapacitor separator

    DOEpatents

    Wei, Chang; Jerabek, Elihu Calvin; LeBlanc, Jr., Oliver Harris

    2001-03-06

    An ultracapacitor includes two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. The electrolyte is a polar aprotic organic solvent and a salt. The porous separator comprises a wet laid cellulosic material.

  19. Hazardous Air Pollutants

    MedlinePlus

    ... menu Learn the Issues Air Chemicals and Toxics Climate Change Emergencies Greener Living Health and Safety Land and Cleanup Pesticides Waste Water Science & Technology Air Climate Change Ecosystems Health Land, Waste and Cleanup Pesticides Substances ...

  20. Controlling Indoor Air Pollution.

    ERIC Educational Resources Information Center

    Nero, Anthony V, Jr.

    1988-01-01

    Discusses the health risks posed by indoor air pollutants, such as airborne combustion products, toxic chemicals, and radioactivity. Questions as to how indoor air might be regulated. Calls for new approaches to environmental protection. (TW)

  1. Evaluation of a comprehensive Eulerian air quality model with multiple chemical species measurements using principal component analysis

    NASA Astrophysics Data System (ADS)

    Li, Shao-Meng; Anlauf, K. G.; Wiebe, H. A.; Bottenheim, J. W.; Puckett, K. J.

    Using a principal component analysis technique and data on atmospheric gases and aerosols at a rural site in Ontario, Canada from the Eulerian model evaluation field study (EMEFS), the Eulerian acid deposition and oxidant model (ADOM) is evaluated. Seventy-nine and 76% of the variances in the data and model output, respectively, are explained by three principal components. They are a chemically aged/ transported component, a diurnal cycle component, and an area emission component, all characterized by their ratios of gases and temporal variation patterns. The ADOM component contributions to sulphur species are in general agreement with the EMEFS components, but with notable differences for key photochemical species including O 3. The temporal variations of the ADOM components are close to those of the EMEFS components. The EMEFS chemically aged/transported component shows a high degree of photochemical processing, with the ratios [NO x]/[TNO y]=0.3 and [O 3]/([TNO y]-[NO x])=9±1. The corresponding ADOM component predicts lower G[NO x]/[TNO y] and [NO 3]/([TNO y]-[NO x]) ratios, probably caused by a chemical mechanism in the model that is too fast, and lower contributions to O 3, NO 2, TNO 3, PAN, TNO y, and HCHO, probably caused by model grid dilution or lower model emissions. The EMEFS diurnal component owes its variance to the daily photochemistry and nighttime dry deposition of the chemical species. In comparison, the matching ADOM component underpredicts the ratio [O 3]/([TNO y]-[NO x]) and the NO 2 consumption and O 3 production but overpredicts the contributions to the other species. The EMEFS emission component represents emissions from local/regional area sources. The corresponding ADOM component underpredicts TNO y by 44% and the fraction of TNO y as NO x compared to the EMEFS component, suggesting that the model has lower emissions of NO x and a photochemical mechanism that converts NO x faster than indicated by the EMEFS results.

  2. Comparing three vegetation monoterpene emission models to measured gas concentrations with a model of meteorology, air chemistry and chemical transport

    SciTech Connect

    Smolander, S.; He, Q.; Mogensen, Ditte; Zhou, L.; Back, J.; Ruuskanen, T.; Noe, S.; Guenther, Alex B.; Aaltonen, H.; Kulmala, M.; Boy, Michael

    2014-10-07

    Biogenic volatile organic compounds (BVOCs) are essential in atmospheric chemistry because of their chemical reactions that produce and destroy tropospheric ozone, their effects on aerosol formation and growth, and their potential influence on global warming. As one of the important BVOC groups, monoterpenes have been a focus of scientific attention in atmospheric research. Detailed regional measurements and model estimates are needed to study emission potential and the monoterpene budget on a global scale. Since the use of empirical measurements for upscaling is limited by many physical and biological factors such as genetic variation, temperature and light, water availability, seasonal changes, and environmental stresses, comprehensive inventories over larger areas are difficult to obtain.

  3. A chemical deposition method to prepare circular planar 147Pm sources for the measurement of particulate emission in air.

    PubMed

    Udhayakumar, J; Gandhi, Shyamala S; Kumar, Manoj; Dash, Ashutosh

    2013-09-01

    This paper describes a method for preparing a circular planar source of 17 mm diameter containing approximately 400 kBq of (147)Pm employing a wet chemical deposition technique to be used in dust monitors. This manuscript described the overall process concept and experimental procedure. The technical feasibility, efficiency of the process and product quality has been evaluated. The quality of the prepared source in terms of nonleachability, uniform distribution of activity and stability, which are necessary attributes of a radioactive source were evaluated and found to be satisfactory. PMID:23733033

  4. Simultaneous and selective decarboxylation of L-serine and deamination of L-phenylalanine in an amino acid mixture--a means of separating amino acids for synthesizing biobased chemicals.

    PubMed

    Teng, Yinglai; Scott, Elinor L; Witte-van Dijk, Susan C M; Sanders, Johan P M

    2016-01-25

    Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. PMID:25976628

  5. Limited effectiveness of heat acclimation to soldiers wearing US Army and US Air Force chemical protective clothing. Technical report

    SciTech Connect

    Chang, S.K.; Gonzalez, R.R.

    1995-11-01

    Heat acclilmation-induced sweating responses have the potential of reducing heat strain for soldiers wearing chemical protective garment. However, this potential benefit is strongly affected by the properties of the garment. If the clothing ensemble permits sufficient evaporative heat dissipation, then heat acclimation becomes helpful in reducing heat strain. On the other hand, if the garment creates an impenetrable barrier to moisture, no benefit can be gained from heat acclimation as the additional sweating cannot be evaporated. We studied 10 subjects exercising on a treadmill while wearing two different U.S. military chemical protective ensembles. Skin heat flux, skin temperature, core temperature, metabolic heat production, and heart rate were measured. We found that the benefit of heat acclimation is strongly dependent on an unimpeded ability of evaporative heat loss from skin areas. The evaporative potential (EP), a measure of thermal insulation modified by moisture permeability, of the clothing ensemble offers a quantitative index useful to determine whether heat acclimation is helpful while protective clothing system. Our data show that when EP is less than 15%, heat acclimation affords no benefit. An evaporative potential graph is created to aid in this determination.

  6. Recent trends of persistent organic pollutants in air in central Europe - Air monitoring in combination with air mass trajectory statistics as a tool to study the effectivity of regional chemical policy

    NASA Astrophysics Data System (ADS)

    Dvorská, A.; Lammel, G.; Holoubek, I.

    We use air mass back trajectory analysis of persistent organic pollutant (POP) levels monitored at a regional background site, Košetice, Czech Republic, as a tool to study the effectiveness of emission reduction measures taken in the last decade in the region. The representativity of the chosen trajectory starting height for air sampling near ground was ensured by excluding trajectories starting at time of inversions lower than their starting height. As the relevant pollutant sources are exclusively located in the atmospheric boundary layer, trajectory segments above this layer were also excluded from the analysis. We used a linear time weight to account for the influence of dispersion and deposition on trace components abundances and to quantify the ground source loading, a continuous measure for the influence of surface emissions. Hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), DDT, and two time periods, the years 1997-1999 and 2004-2006, were studied. The pollutant levels transported to Košetice decreased for all substances except HCB. Except for lindane seasonal emissions were insignificant. Increasing emissions of HCB were at least partly linked to the 2002 floods in the Danube basin. Major emissions of 1997-1999 which decreased significantly were in France (lindane), western Poland, Hungary and northern ex-Yugoslavia (technical HCH), and the Czech Republic (DDT). Emissions remaining in 2004-2006 include HCB and DDT in the northern Czech Republic, HCB and PCBs in Germany. Besides changes in emission strength meteorological factors influence the level of transported pollutant concentrations. The prevailing air flow pattern limits the geographic coverage of this analysis to central Europe and parts of western Europe. However, no POP monitoring stations exist in areas suitable for a possible extension of the study area.

  7. Chemical reacting flows

    NASA Technical Reports Server (NTRS)

    Mularz, Edward J.; Sockol, Peter M.

    1987-01-01

    Future aerospace propulsion concepts involve the combination of liquid or gaseous fuels in a highly turbulent internal air stream. Accurate predictive computer codes which can simulate the fluid mechanics, chemistry, and turbulence combustion interaction of these chemical reacting flows will be a new tool that is needed in the design of these future propulsion concepts. Experimental and code development research is being performed at Lewis to better understand chemical reacting flows with the long term goal of establishing these reliable computer codes. The approach to understanding chemical reacting flows is to look at separate simple parts of this complex phenomena as well as to study the full turbulent reacting flow process. As a result research on the fluid mechanics associated with chemical reacting flows was initiated. The chemistry of fuel-air combustion is also being studied. Finally, the phenomena of turbulence-combustion interaction is being investigated. This presentation will highlight research, both experimental and analytical, in each of these three major areas.

  8. Dynamics of effusive and diffusive gas separation on pillared graphene.

    PubMed

    Wesołowski, Radosław P; Terzyk, Artur P

    2016-06-22

    Pillared graphene structures, from a practical viewpoint, are very interesting novel carbon materials. Combining the properties of graphene and nanotubes, such as durability, chemical purity and a controlled structure, they were proven to be effective membranes for noble gas separation processes. Here, we examine their possible use for other, more commercially useful gas mixture separation, i.e. air and coal gas. The mechanism of air gas transport through the pillar channels is studied, and the prospective application of 2-D pillared membranes in effusion-like processes provided. The separative abilities of hybrid systems consisting of membranes with different channel diameters in relation to coal gas are proven to be promising. PMID:27297664

  9. Chemical Properties of Air Pollutants and Cause-Specific Hospital Admissions among the Elderly in Atlanta, Georgia

    PubMed Central

    Zanobetti, Antonella; Schwartz, Joel; Coull, Brent A.

    2011-01-01

    Background: Health risks differ by fine particle (aerodynamic diameter ≤ 2.5 μm) component, although with substantial variability. Traditional methods to assess component-specific risks are limited, suggesting the need for alternative methods. Objectives: We examined whether the odds of daily hospital admissions differ by pollutant chemical properties. Methods: We categorized pollutants by chemical properties and examined their impacts on the odds of daily hospital admissions among Medicare recipients > 64 years of age in counties in Atlanta, Georgia, for 1998–2006. We analyzed data in two stages. In the first stage we applied a case-crossover analysis to simultaneously estimate effects of 65 pollutants measured in the Aerosol Research and Inhalation Epidemiology Study on cause-specific hospital admissions, controlling for temperature and ozone. In the second stage, we regressed pollutant-specific slopes from the first stage on pollutant properties. We calculated uncertainty estimates using a bootstrap procedure. We repeated the two-stage analyses using coefficients from first-stage models that included single pollutants plus ozone and meteorological variables only. We based our primary analyses on exposures on day of admission. Results: We found that 24-hr transition metals and alkanes were associated with increased odds [0.26%; 95% confidence interval (CI), 0.02–0.48; and 0.37%; 95% CI, 0.04–0.72, respectively] of hospital admissions for cardiovascular disease (CVD). Transition metals were significantly associated with increased hospital admissions for ischemic heart disease, congestive heart failure, and atrial fibrillation. Increased respiratory-related hospital admissions were significantly associated with alkanes. Aromatics and microcrystalline oxides were significantly associated with decreased CVD- and respiratory-related hospital admissions. Conclusions: The two-stage approach showed transition metals to be consistently associated with increased

  10. Chemical compositions responsible for inflammation and tissue damage in the mouse lung by coarse and fine particulate samples from contrasting air pollution in Europe.

    PubMed

    Happo, Mikko S; Hirvonen, Maija-Riitta; Halinen, Arja I; Jalava, Pasi I; Pennanen, Arto S; Sillanpaa, Markus; Hillamo, Risto; Salonen, Raimo O

    2008-11-01

    Inflammation is regarded as an important mechanism in mortality and morbidity associated with exposures of cardiorespiratory patients to urban air particulate matter. We investigated the association of the chemical composition and sources of urban air fine (PM(2.5-0.2)) and coarse (PM(10-2.5)) particulate samples with the inflammatory activity in the mouse lung. The particulate samples were collected during selected seasons in six European cities using a high-volume cascade impactor. Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. At 4, 12, and 24 h after the exposure, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cell number, total protein, and cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, and KC). Dicarboxylic acids and transition metals, especially Ni and V, in PM(2.5-0.2) correlated positively and some secondary inorganic ions (NO3(-), NH4(+)) negatively with the inflammatory activity. Total organic matter and SO4(2-) had no consistent correlations. In addition, the soil-derived constituents (Ca2+, Al, Fe, Si) showed positive correlations with the PM(2.5-0.2)-induced inflammatory activity, but their role in PM(10-2.5) remained obscure, possibly due to largely undefined biogenic material. Markers of poor biomass and coal combustion, i.e., monosaccharide anhydrides and As, were associated with elevated PAH contents in PM(2.5-0.2) and a consistent immunosuppressive effect. Overall, our results support epidemiological findings that the local sources of incomplete combustion and resuspended road dust are important in urban air particulate pollution-related health effects. PMID:18855153

  11. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH+, MOH+, and MO2H+, respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH+ sharply decreased, that of MOH+ increased once and then decreased, and that of MO2H+ sharply increased until reaching a plateau. The signal intensity of MO2H+ at the plateau was 40 times higher than that of MH+ and 100 times higher than that of MOH+ in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO2H+ signal in the concentration range up to 60 μg/m3, which is high enough for hygiene management. In the low concentration range lower than 3 μg/m3, which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-μg/m3 vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  12. Simultaneous removal of ammonia, P and COD from anaerobically digested piggery wastewater using an integrated process of chemical precipitation and air stripping.

    PubMed

    Quan, Xuejun; Ye, Changying; Xiong, Yanqi; Xiang, Jinxin; Wang, Fuping

    2010-06-15

    The paper presented an efficient integrated physicochemical process, which consists of chemical precipitation and air stripping, for the simultaneous removal of NH(3)-N, total P and COD from anaerobically digested piggery wastewater. In the integrated process, Ca(OH) (2) was used as the precipitant for NH(4)(+), PO(4)(3-) and organic phosphorous compounds, and as the pH adjuster for the air stripping of residual ammonia. The possibility of the suggested process and the related mechanisms were first investigated through a series of equilibrium tests. Laboratory scale tests were carried out to validate the application possibility of the integrated process using a new-patented water sparged aerocyclone reactor (WSA). The WSA could be effectively used for the simultaneous removal of NH(3)-N, total P and COD. 3g/L of Ca(OH) (2) is a proper dosage for the simultaneous removal. The simultaneous removal of NH(3)-N, total P and COD in the WSA reactor could be easily optimized by selecting a proper air inlet velocity and a proper jet velocity of the liquid phase. In all the cases, the removal efficiencies of the NH(3)-N, total P and COD were over 91%, 99.2% and 52% for NH(3)-N, total P and COD, respectively. The formed precipitates in the process could be easily settled down from the suspension system. Therefore, the integrated process provided an efficient alternative for the simultaneous removal of NH(3)-N, total P and COD from the wastewater. PMID:20189301

  13. Comparison of negative-ion proton-transfer with iodide ion chemical ionization mass spectrometry for quantification of isocyanic acid in ambient air

    NASA Astrophysics Data System (ADS)

    Woodward-Massey, Robert; Taha, Youssef M.; Moussa, Samar G.; Osthoff, Hans D.

    2014-12-01

    Isocyanic acid (HNCO) is a trace gas pollutant of potential importance to human health whose measurement has recently become possible through the development of negative-ion proton-transfer chemical ionization mass spectrometry (NI-PT-CIMS) with acetate reagent ion. In this manuscript, an alternative ionization and detection scheme, in which HNCO is quantified by iodide CIMS (iCIMS) as a cluster ion at m/z 170, is described. The sensitivity was inversely proportional to water vapor concentration but could be made independent of humidity changes in the sampled air by humidifying the ion-molecule reaction (IMR) region of the CIMS. The performance of the two ionization schemes was compared and contrasted using ambient air measurements of HNCO mixing ratios in Calgary, AB, Canada, by NI-PT-CIMS with acetate reagent ion from Dec 16 to 20, 2013, and by the same CIMS operated in iCIMS mode from Feb 3 to 7, 2014. The iCIMS exhibited a greater signal-to-noise ratio than the NI-PT-CIMS, not because of its sensitivity, which was lower (˜0.083 normalized counts per second (NCPS) per parts-per-trillion by volume (pptv) compared to ˜9.7 NCPS pptv-1), but because of a much lower and more stable background (3 ± 4 compared to a range of ˜2 × 103 to ˜6 × 103 NCPS). For the Feb 2014 data set, the HNCO mixing ratios in Calgary air ranged from <12 to 94 pptv (median 34 pptv), were marginally higher at night than during day, and correlated with nitrogen oxide (NOx = NO + NO2) mixing ratios and submicron particle volume. The ratios of HNCO to NOx observed are within the range of emission ratios reported for gasoline-powered motor vehicles.

  14. Chemical compositions responsible for inflammation and tissue damage in the mouse lung by coarse and fine particulate samples from contrasting air pollution in Europe

    SciTech Connect

    Happo, M.S.; Hirvonen, M.R.; Halinen, A.I.; Jalava, P.I.; Pennanen, A.S.; Sillanpaa, M.; Hillamo, R.; Salonen, R.O.

    2008-07-01

    Inflammation is regarded as an important mechanism in mortality and morbidity associated with exposures of cardiorespiratory patients to urban air particulate matter. We investigated the association of the chemical composition and sources of urban air fine (PM2.5-0.2) and coarse (PM10-2.5) particulate samples with the inflammatory activity in the mouse lung. The particulate samples were collected during selected seasons in six European cities using a high-volume cascade impactor. Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. At 4, 12, and 24 h after the exposure, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cell number, total protein, and cytokines (tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and KC). Dicarboxylic acids and transition metals, especially Ni and V, in PM2.5-0.2 correlated positively and some secondary inorganic ions (NO{sub 3}{sup -}, NH{sub 4}{sup +}) negatively with the inflammatory activity. Total organic matter and SO{sub 4}{sup 2-} had no consistent correlations. In addition, the soil-derived constituents (Ca{sup 2+}, Al, Fe, Si) showed positive correlations with the PM2.5-0.2-induced inflammatory activity, but their role in PM10 (2.5) remained obscure, possibly due to largely undefined biogenic material. Markers of poor biomass and coal combustion, i.e., monosaccharide anhydrides and As, were associated with elevated PAH contents in PM2.5 (0.2) and a consistent immunosuppressive effect. Overall, our results support epidemiological findings that the local sources of incomplete combustion and resuspended road dust are important in urban air particulate pollution-related health effects.

  15. Teaching Separations: Why, What, When, and How?

    ERIC Educational Resources Information Center

    Wankat, Phillip C.

    2001-01-01

    Describes how and when to teach separation science to chemical engineering students. Separation science is important for industrial businesses involving the manufacture of adsorption systems, distillation columns, extractors, and other separation equipment and techniques. (Contains 13 references.) (YDS)

  16. Effects of coal storage in air on physical and chemical properties of coal and on gas adsorption

    USGS Publications Warehouse

    Mastalerz, Maria; Solano-Acosta, W.; Schimmelmann, A.; Drobniak, A.

    2009-01-01

    This paper investigates changes in the high-volatile bituminous Lower Block Coal Member from Indiana owing to moisture availability and oxidation in air at ambient pressure and temperature over storage time. Specifically, it investigates changes in chemistry, in surface area, and pore structure, as well as changes in methane and carbon dioxide adsorption capacities. Our results document that the methane adsorption capacity increased by 40%, whereas CO2 adsorption capacity increased by 18% during a 13-month time period. These changes in adsorption are accompanied by changes in chemistry and surface area of the coal. The observed changes in adsorption capacity indicate that special care must be taken when collecting samples and preserving coals until adsorption characteristics are measured in the laboratory. High-pressure isotherms from partially dried coal samples would likely cause overestimation of gas adsorption capacities, lead to a miscalculation of coal-bed methane prospects, and provide deceptively optimistic prognoses for recovery of coal-bed methane or capture of anthropogenic CO2. ?? 2009 Elsevier B.V. All rights reserved.

  17. Surfactants as bubble surface modifiers in the flotation of algae: dissolved air flotation that utilizes a chemically modified bubble surface.

    PubMed

    Henderson, Rita K; Parsons, Simon A; Jefferson, Bruce

    2008-07-01

    In this paper we present an investigation into the use of bubbles modified with surfactants in dissolved air flotation (DAF). Bubble modification was investigated by dosing surfactants of varying character into the saturator of a DAF unit in turn. The cell removal efficiency only improved when using a cationic surfactant where optimum removal of Microcystis aeruginosa cells was obtained when using 0.0022-0.004 mequiv L(-1) surfactant. However, the magnitude of the removal differed according to the hydrophobicity of the surfactant. Typically, the more efficiently the surfactant adsorbed at the bubble interface, the better the removal efficiency. When the dose to saturator ratio was kept constant and the recycle ratio varied, the removal efficiency improved with increasing recycle ratio, reaching a maximum removal efficiency of 87% for M. aeruginosa. This value was comparable with that predicted by a theoretical model. The bubble collection efficiency of a maximum of two cells per bubble was constant irrespective of the influent cell number or recycle ratio. Treatment of additional species in this way revealed a relationship between increasing size and both increasing removal efficiency and decreasing surfactant dose, which is supported by theoretical relationships. PMID:18678021

  18. Airborne rotary separator study

    NASA Astrophysics Data System (ADS)

    Drnevich, R. F.; Nowobilski, J. J.

    1992-12-01

    Several air breathing propulsion concepts for future earth-to-orbit transport vehicles utilize air collection and enrichment, and subsequent storage of liquid oxygen for later use in the vehicle mission. Work performed during the 1960's established the feasibility of substantially reducing weight and volume of a distillation type air separator system by operating the distillation elements in high 'g' fields obtained by rotating the separator assembly. The purpose of this study was to evaluate various fuels and fuel combinations with the objective of minimizing the weight and increase the ready alert capability of the plane. Fuels will be used to provide energy as well as act as heat sinks for the on-board heat rejection system. Fuel energy was used to provide power for air separation as well as to produce refrigeration for liquefaction of oxygen enriched air, besides its primary purpose of vehicle propulsion. The heat generated in the cycle was rejected to the fuel and water which is also carried on board the vehicle.The fuels that were evaluated include JP4, methane, and hydrogen. Hydrogen served as a comparison to the JP4 and methane cases.

  19. Airborne rotary separator study

    NASA Technical Reports Server (NTRS)

    Drnevich, R. F.; Nowobilski, J. J.

    1992-01-01

    Several air breathing propulsion concepts for future earth-to-orbit transport vehicles utilize air collection and enrichment, and subsequent storage of liquid oxygen for later use in the vehicle mission. Work performed during the 1960's established the feasibility of substantially reducing weight and volume of a distillation type air separator system by operating the distillation elements in high 'g' fields obtained by rotating the separator assembly. The purpose of this study was to evaluate various fuels and fuel combinations with the objective of minimizing the weight and increase the ready alert capability of the plane. Fuels will be used to provide energy as well as act as heat sinks for the on-board heat rejection system. Fuel energy was used to provide power for air separation as well as to produce refrigeration for liquefaction of oxygen enriched air, besides its primary purpose of vehicle propulsion. The heat generated in the cycle was rejected to the fuel and water which is also carried on board the vehicle.The fuels that were evaluated include JP4, methane, and hydrogen. Hydrogen served as a comparison to the JP4 and methane cases.

  20. Air cleaning system

    SciTech Connect

    Tidwell, J.H.

    1987-06-16

    This patent describes an air cleaning system comprising: a motor housing; a motor mounted within the housing; a fan attached to and rotatably driven by the motor; a fan chamber surrounding the fan and having an air inlet and outlet; a separator housing means mounted adjacent to and in spaced relation with the motor housing, the separator housing means having an inlet disposed in communication with a chamber within separator housing means; an outlet disposed in communication with the fan chamber; an air driven separator means mounted in chamber of the separator housing means to receive airflow from inlet for rotation of the separator means and removal of foreign matter from airflow by centrifugal force responsive to rotation of the separator means; the airflow is further directed through the outlet of separator housing means to the fan chamber to be ejected by the fan.