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1

Climate Policy Design: Interactions among Carbon Dioxide, Methane, and Urban Air Pollution Constraints  

E-print Network

Climate Policy Design: Interactions among Carbon Dioxide, Methane, and Urban Air Pollution Policy Design: Interactions among Carbon Dioxide, Methane, and Urban Air Pollution Constraints by Marcus. The third case examines the benefits of increased policy coordination between air pollution constraints

de Weck, Olivier L.

2

Carbon dioxide emissions from international air freight  

NASA Astrophysics Data System (ADS)

Greenhouse gas emissions from international air transport were excluded from reduction targets under the Kyoto Protocol, partly because of difficulties with quantifying and apportioning such emissions. Although there has been a great deal of recent research into calculating emissions from aeroplane operations globally, publicly available emissions factors for air freight emissions are scarce. This paper presents a methodology to calculate the amount of fuel burnt and the resulting CO 2 emissions from New Zealand's internationally air freighted imports and exports in 2007. This methodology could be applied to other nations and/or regions. Using data on fuel uplift, air freight and air craft movements, and assumptions on mean passenger loadings and the mass of passengers and air freight, CO 2 emissions factors of 0.82 kg CO 2 per t-km and 0.69 kg CO 2 per t-km for short-haul and long-haul journeys, respectively, were calculated. The total amount of fuel consumed for the international air transport of New Zealand's imports and exports was calculated to be 0.21 Mt and 0.17 Mt respectively, with corresponding CO 2 emissions of 0.67 Mt and 0.53 Mt.

Howitt, Oliver J. A.; Carruthers, Michael A.; Smith, Inga J.; Rodger, Craig J.

2011-12-01

3

Performance of air filters cleaned by supercritical carbon dioxide  

Microsoft Academic Search

A new technique based on the use of supercritical carbon dioxide (CO2) for cleaning HEPA filters was developed. Glass fiber filters and polytetrafluoroethylene (PTFE) membranes loaded with dioctylphthalate (DOP) droplets were cleaned with supercritical carbon dioxide under various conditions. The cleaning performance was evaluated by the weight recovery of the filter media and the recoveries of their collection efficiencies and

Takao Ito; Yoshio Otani; Hiroshi Inomata

2004-01-01

4

Indoor Air Quality in Schools (IAQ): The Importance of Monitoring Carbon Dioxide Levels.  

ERIC Educational Resources Information Center

This article highlights indoor air quality and exposure to pollutants at school. Typical air pollutants within schools include environmental tobacco smoke, formaldehyde, volatile organic compounds, nitrogen oxides, carbon monoxide, carbon dioxide, allergens, pathogens, radon, pesticides, lead, and dust. Inadequate ventilation, inefficient…

Sundersingh, David; Bearg, David W.

5

Methane and carbon dioxide fluxes in soils evaluated by 222 Rn flux and soil air concentration profiles  

Microsoft Academic Search

Measurements of methane and carbon dioxide fluxes from diverse soils in the surroundings of Málaga (Spain) were made. Methane and carbon dioxide fluxes were carried out by an indirect method from simultaneous measurements of 222Rn flux from the soil surface in parallel with concentration profile measurements of 222Rn, methane and carbon dioxide in the air of soil. Correlations found between

C. Dueñas; M. C. Fernández; J. Carretero; E. Liger

1999-01-01

6

Temperature VS Carbon Dioxide  

NSDL National Science Digital Library

In this activity, students examine the relationship between carbon dioxide levels and global temperature change by studying a graph of these two variables. They will discover that by using data from ice cores, scientists can determine temperature and carbon dioxide levels in the air as far back as a hundred thousand years in the past. The students try to predict which variable is the independent one and then make a graph of temperature change and carbon dioxide levels. After making their graph, students describe the relationship between temperature and carbon dioxide levels in the atmosphere to determine if their predictions were correct.

7

THE OXIDATION AND RELEASE OF IODINE131 FROM URANIUM SLUGS OXIDIZING IN AIR AND CARBON DIOXIDE  

Microsoft Academic Search

Experiments to determine the oxidation rate, particle size distribution ; of oxide, and release of I¹³¹ from one kilogram, trace irradiated uranium ; slugs oxidizing at temperatures up to 1000 deg C in air and carbon dioxide are ; described. The release of iodine as a result of rapid melting of uranlum ls also ; investigated. lt is concluded that

W. J. Megaw; R. C. Chadwick; A. C. Wells; J. E. Bridges

1961-01-01

8

On the causal link between carbon dioxide and air pollution mortality  

Microsoft Academic Search

Greenhouse gases and particle soot have been linked to enhanced sea-level, snowmelt, disease, heat stress, severe weather, and ocean acidification, but the effect of carbon dioxide (CO2) on air pollution mortality has not been examined or quantified. Here, it is shown that increased water vapor and temperatures from higher CO2 separately increase ozone more with higher ozone; thus, global warming

Mark Z. Jacobson

2008-01-01

9

Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture  

PubMed Central

Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 44 square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84?Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials. PMID:24964404

Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

2014-01-01

10

Carbon dioxide dangers demonstration model  

USGS Publications Warehouse

Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

Venezky, Dina; Wessells, Stephen

2010-01-01

11

CARBON DIOXIDE AND OXYGEN-NITROGEN RATIOS AS FACTORS AFFECTING SALMON SURVIVAL IN AIR-SUPERSATURATED WATER  

EPA Science Inventory

Juvenile sockeye salmon (Oncorhynchus nerka) were exposed to lethal levels of air-supersaturated water (120 percent, 125 percent, 130 percent total gas saturation) containing different oxygen-nitrogen ratios and different carbon dioxide concentrations. Fish mortality was not sign...

12

Spatial and seasonal variability of the air-sea equilibration timescale of carbon dioxide  

NASA Astrophysics Data System (ADS)

The exchange of carbon dioxide between the ocean and the atmosphere tends to bring waters within the mixed layer toward equilibrium by reducing the partial pressure gradient across the air-water interface. However, the equilibration process is not instantaneous; in general, there is a lag between forcing and response. The timescale of air-sea equilibration depends on several factors involving the depth of the mixed layer, wind speed, and carbonate chemistry. We use a suite of observational data sets to generate climatological and seasonal composite maps of the air-sea equilibration timescale. The relaxation timescale exhibits considerable spatial and seasonal variations that are largely set by changes in mixed layer depth and wind speed. The net effect is dominated by the mixed layer depth; the gas exchange velocity and carbonate chemistry parameters only provide partial compensation. Broadly speaking, the adjustment timescale tends to increase with latitude. We compare the observationally derived air-sea gas exchange timescale with a model-derived surface residence time and a data-derived horizontal transport timescale, which allows us to define two nondimensional metrics of equilibration efficiency. These parameters highlight the tropics, subtropics, and northern North Atlantic as regions of inefficient air-sea equilibration where carbon anomalies are relatively likely to persist. The efficiency parameters presented here can serve as simple tools for understanding the large-scale persistence of air-sea disequilibrium of CO2 in both observations and models.

Jones, Daniel C.; Ito, Takamitsu; Takano, Yohei; Hsu, Wei-Ching

2014-11-01

13

Brookhaven National Laboratory free-air carbon dioxide enrichment forest prototype -- Interim report  

SciTech Connect

A variety of approaches have been used in fumigation experiments to quantify the effects of increasing atmospheric carbon dioxide concentration ([CO{sub 2}]{sub atm}) on plants. Mot of these approaches, reviewed elsewhere (Allen 1992), entail some type of enclosure or chamber. Chambers provide containment of the CO{sub 2}-enriched air and in this way reduce the amount of CO{sub 2} required for the experiment. At the same time, chambers alter microclimate conditions in a variety of ways so that there is a significant chamber effect on the plants within. Free-air carbon dioxide enrichment (FACE) is an alternative experimental strategy in which CO{sub 2}-enriched air is released into the ambient environment in such a way as to provide effective experimental control over [CO{sub 2}]{sub atm} without causing any change in other environmental variables. Early types of free-air exposure systems were built in the Netherlands and England for exposing vegetation to elevated concentrations of atmospheric trace gases. The FACE Program at Brookhaven National Laboratory (BNL) considered these original ideas in designing the BNL FACE systems. The purpose of the current BNL project in the Duke Forest is to develop a FACE system that can provide adequate control over [CO{sub 2}]{sub atm} in a tall forest setting. This report is a preliminary overview of the data and much remains to be done in the analysis.

Hendrey, G.R.; Lewin, K.F.; Nagy, J.

1994-08-01

14

Adsorption of fluoro surfactants at air-water and water-carbon dioxide interfaces  

Microsoft Academic Search

Aqueous phase behaviour, and water-in-carbon dioxide microemulsion formation, were studied with two model fluorinated anionic\\u000a surfactants, sodium bis(1H\\/,lH\\/-per-fluoropentyl)-2-sulfosuccinate (di-CF4) and sodium bis(1H,1H,5H-octafluoropentyl)-2-sulfosuccinate (di-HCF4). The properties are compared to the common, branched-chain, hydrocarbon surfactant\\u000a Aerosol-OT (AOT). For the fluoro surfactants, surface excesses at the air-solution interface, measured by tensiometry and\\u000a neutron reflection, agreed well, and the ?-ln(activity) curves were consistent with

J. Eastoe; A. M. Downer; A. Paul; D. C. Steytler; E. Rumsey

15

Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis.  

PubMed

An ideal chemical sorbent for carbon dioxide capture from ambient air (air capture) must have a number of favourable properties, such as environmentally benign behaviour, a high affinity for CO(2) at very low concentration (400 ppm), and a low energy cost for regeneration. The last two properties seem contradictory, especially for sorbents employing thermal swing adsorption. On the other hand, thermodynamic analysis shows that the energy cost of an air capture device need only be slightly larger than that of a flue gas scrubber. The moisture swing separation process studied in this paper provides a novel approach to low cost CO(2) capture from air. The anionic exchange resin sorbent binds CO(2) when dry and releases it when wet. A thermodynamic model with coupled phase and chemical equilibria is developed to study the complex H(2)O-CO(2)-resin system. The moisture swing behaviour is compatible with hydration energies changing with the activity of water on the resin surfaces. This activity is in turn set by the humidity. The rearrangement of hydration water on the resin upon the sorption of a CO(2) molecule is predicted as a function of the humidity and temperature. Using water as fuel to drive the moisture swing enables an economical, large-scale implementation of air capture. By generating CO(2) with low partial pressures, the present technology has implications for in situ CO(2) utilizations which require low pressure CO(2) gas rather than liquid CO(2). PMID:23172123

Wang, Tao; Lackner, Klaus S; Wright, Allen B

2013-01-14

16

CARBON DIOXIDE EMISSION REDUCTION  

E-print Network

CARBON DIOXIDE EMISSION REDUCTION TECHNOLOGIES AND MEASURES IN US INDUSTRIAL SECTOR FINAL REPORT TO KOREA ENVIRONMENT INSTITUTE FEBRUARY 2007 #12;B #12;C CARBON DIOXIDE EMISSION REDUCTION TECHNOLOGIES.5 Primary Energy Use and Carbon Dioxide Emissions for Selected US Chemical Subsectors in 1994

Delaware, University of

17

Fine root responses of mature deciduous forest trees to free air carbon dioxide enrichment (FACE)  

Microsoft Academic Search

Summary 1. Elevated atmospheric carbon dioxide (CO 2 ) concentrations have often been reported to increase carbon allocation below-ground, particularly to fine root production. However, for trees these responses have primarily been studied in young expanding systems while the evidence for late successional systems that have reached steady state above- and below-ground is very limited. 2. At the Swiss Canopy

Martin Bader; Erika Hiltbrunner; Christian Körner

2009-01-01

18

Carbon dioxide exchange between air and seawater: no evidence for rate catalysis  

SciTech Connect

It has been suggested that enzymatic catalysis plays a major role in regulating the mass transport of carbon dioxide from the atmosphere into the oceans. Evidence for this mechanism was not found in a series of gas exchange experiments in which the gas transfer rate coefficients for samples obtained from various natural seawaters, with and without the addition of carbonic anhydrase, were compared with those from artificial seawater. Wind-induced turbulence appears to be the major factor controlling the ocean's response to anthropogenic increases in atmospheric carbon dioxide. 2 figures.

Goldman, J.C.; Dennett, M.R.

1983-04-08

19

Carbon Dioxide & Global Warming  

E-print Network

Carbon Dioxide & Global Warming University of MiaMi rosenstiel sChool of Marine anD atMospheriC s ­ it allows sunlight in, but gases in the atmosphere, especially carbon dioxide (CO2 ), allow less to breathe. Respi- ration by these organisms returns this carbon to the atmosphere as CO2 . Unfortunately

Miami, University of

20

The carbon dioxide cycle  

USGS Publications Warehouse

The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

James, P.B.; Hansen, G.B.; Titus, T.N.

2005-01-01

21

Background component of carbon dioxide concentration in the near-surface air  

NASA Astrophysics Data System (ADS)

The data on measurements of carbon dioxide concentrations in the near-surface air in the territory of the European part of Russia using Fourier transform spectroscopy are presented. Analysis of these data showed that temporal variations in CO2 concentrations included ˜18% of relatively high, short-lived concentrations that appear during temperature inversions and fires. The measurement results are separated into the regional natural background CO2 concentration and the anthropogenic admixture. The seasonal component is distinguished in the background CO2 concentration. The maxima and minima of seasonal CO2 variations fall most often within February and July, respectively, at an average amplitude of 20.2 ± 3.8 ppm. The coefficient of pair correlation between seasonal CO2 concentrations and temperature is -0.85. Spectral analysis revealed a large number of composite oscillations of the background CO2 concentration, from 2 to 126 months in period. A simple model using the parameters of these oscillations describes the temporal variations in background CO2 concentration with an error of less than 1%. The anthropogenic admixture of CO2 into the atmosphere consists of a random component and a long-term trend. For 13 years of observations, the anthropogenic admixture was ˜33 ppm at an average growth rate of ˜2.04 ppm/yr.

Aref'ev, V. N.; Kamenogradsky, N. Ye.; Kashin, F. V.; Shilkin, A. V.

2014-11-01

22

Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation  

SciTech Connect

Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentrations were studied in a Reading silt loam under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samples permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N{sub 2}O concentrations were near atmospheric levels for a majority of the study period in the prairie site but were significantly higher in the cultivated site. Annual mean N{sub 2}O concentrations were 0.403 and 1.09 {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Soil air CO{sub 2} annual mean concentrations were 1.56 {times} 10{sup 4} and 1.10 {times} 10{sup 4} {micro}L L{sup {minus}1} and ranged from 0.096 {times} 10{sup 4} to 6.45 {times} 10{sup 4} {micro}L L{sup {minus}1} and 0.087 {times} 10{sup 4} to 3.59 {times} 10{sup 4} {micro}L L{sup {minus}1} in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N{sub 2}O and CO{sub 2} concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO{sub 2} at both sites did not change markedly over winter months, but CO{sub 2} and N{sub 2}O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.

Sotomayor, D. [Univ. of Puerto Rico, Mayagueez (Puerto Rico). Agronomy and Soils Dept.; Rice, C.W. [Kansas State Univ., Manhattan, KS (United States). Dept. of Agronomy

1999-05-01

23

Aversive reactions of turkeys to argon, carbon dioxide and a mixture of carbon dioxide and argon.  

PubMed

The reactions of turkeys to the presence of either 90 per cent argon in air (anoxia), 72 per cent carbon dioxide in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air with 3 per cent residual oxygen were tested. The majority of the turkeys did not avoid a feeding chamber containing either argon or the mixture of carbon dioxide and argon, but 50 per cent of the turkeys avoided a feeding chamber containing 72 per cent carbon dioxide in air. It is concluded that from the point of view of welfare, either 90 per cent argon in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, would be preferable to a high concentration of carbon dioxide for stunning/killing turkeys. PMID:8799986

Raj, A B

1996-06-15

24

Production of Carbon Dioxide  

NSDL National Science Digital Library

In this chemistry activity, learners use common chemicals to produce carbon dioxide and observe its properties. This resource includes brief questions for learners to answer after the experiment. Use this activity to introduce learners to carbon dioxide and its use as a fire extinguisher. Note: this activity involves an open flame.

House, The S.

2014-01-28

25

Carbon Dioxide Emission Estimates  

NSDL National Science Digital Library

The Carbon Dioxide Information Analysis Center of the Oak Ridge National Laboratory provides this new data on carbon dioxide emissions from fossil fuel burning, hydraulic cement production, and gas flaring in 1995. Data for one degree grid cells can be downloaded from the site in addition to code for analysis of the data.

26

Carbon Dioxide and Climate.  

ERIC Educational Resources Information Center

The amount of carbon dioxide in the atmosphere is increasing at a rate that could cause significant warming of the Earth's climate in the not too distant future. Oceanographers are studying the role of the ocean as a source of carbon dioxide and as a sink for the gas. (Author/BB)

Brewer, Peter G.

1978-01-01

27

Molecular Structure of Carbon Dioxide  

NSDL National Science Digital Library

Carbon dioxide was first described in the 17th century by Jan Baptist van Helmont, a Belgium chemist. The chemical CO2 is released into the atmosphere when carbon-containing fossil fuels like oil, natural gas, and coal are burned in air. It is also produced by various microorganisms in fermentation and is breathed out by animals. Plants absorb carbon dioxide during photosynthesis, using both the carbon and the oxygen to construct carbohydrates. Every year the amount of CO2 in the atmosphere is increasing. CO2 build-up in the atmosphere is caused by deforestation, therefore reducing the number of trees available to absorb CO2. Excess CO2 in the environment causes Global Warming and the Greenhouse Effect. It is also toxic to humans since inhalation of large amounts of CO2 can cause suffocation. Some beverages, such as beer and sparkling wine contain carbon dioxide as a result of fermentation.

2002-08-15

28

Intermittent or Continuous Carbon Dioxide Insufflation for De-Airing of the Cardiothoracic Wound Cavity? An Experimental Study with a New Gas-Diffuser  

Microsoft Academic Search

Insufflation of carbon dioxide into the chest wound is used in open-heart surgery to de-air the heart and great vessels. In a cardiothoracic wound model, we com- pared the degree of air displacement achieved by a new insufflation device, a gas-diffuser, with that of a thin open-ended tube during steady-state and with carbon dioxide flows of 2.5, 5, 7.5, and

Peter Svenarud; Mikael Persson; Jan van der Linden

2003-01-01

29

Out of thin air: Sensory detection of oxygen and carbon dioxide  

PubMed Central

Oxygen and carbon dioxide levels vary in different environments and locally fluctuate during respiration and photosynthesis. Recent studies in diverse animals have identified sensory neurons that detect these external variations and direct a variety of behaviors. Detection allows animals to stay within a preferred environment as well as identify potential food or dangers. The complexity of sensation is reflected in the fact that neurons compartmentalize detection into increases, decreases, short-range and long-range cues. Animals also adjust their responses to these prevalent signals in context of other cues, allowing for flexible behaviors. In general, the molecular mechanisms for detection suggest that sensory neurons adopted ancient strategies for cellular detection and coupled them to brain activity and behavior. This review highlights the multiple strategies that animals use to extract information about their environment from variations in oxygen and carbon dioxide. PMID:21262460

Scott, Kristin

2011-01-01

30

Extraction and detection of pesticide residues from air filter inserts using supercritical carbon dioxide  

SciTech Connect

Trace quantities of airborne herbicide residues were collected on adsorbent bed cartridges and were subsequently extracted from the adsorbent using supercritical carbon dioxide. An apparatus was constructed to facilitate the extraction and recovery of the desired analytes. The resulting extracts were analyzed using gas chromatography/mass spectrometry (GC/MS) or high performance liquid chromatography (HPLC) techniques. Results are presented for a series of analytes representative of common commercial pesticides or herbicides.

Zemanian, T.S.; Robins, W.H.; Lee, R.N.; Wright, B.W.

1994-10-01

31

Sampling Carbon Dioxide  

NSDL National Science Digital Library

In this lab activity, student teams hypothesize which source has a greater becomes CO² concentration: their breath, auto exhaust, or air in the classroom. They test gas samples from each of these sources, plot data, and hypothesize about the respective role engine exhaust and animal respiration play in contemporary climate change. The lab procedures require Bromthymol Blue indicator solution (BTB), household ammonia, vinegar, and balloons. Links to videos supporting the investigations are provided. This activity is supported by a textbook chapter, "How is Carbon Dioxide Measured?," part of the unit, Climate Change, in Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

32

Pressurized Fuel/Air Operated Solid Oxide Fuel Cell Combined Carbon-Dioxide-Capturing High-Performance Power Generation System  

NASA Astrophysics Data System (ADS)

The authors recently proposed a solid oxide fuel cell (SOFC) and closed-cycle MHD combined carbon-dioxide-capturing high-performance power generation system using pure oxygen as the oxidant. This combined system can make the best use of the merit of pure oxygen combustion, while its demerit of efficiency deterioration by large required power for oxygen generation still remains. In the present study, the authors modify this already proposed system and newly propose an improved carbon-dioxide-capturing SOFC/MHD combined power generation system with higher total thermal efficiency. In the system, pure oxygen is only supplied to the afterburner to save the required power for oxygen generation, and pressurized air is selected as the oxidant gas of the SOFC. The saved power amounts to about 5% of the thermal input, resulting in the very high total thermal efficiency of 67.53% (HHV) or 74.94% (LHV), which is considered to be the highest possible value as the total thermal efficiency of carbon-dioxide-capturing systems. The proposed system is worth carrying out further research and development.

Inui, Yoshitaka; Ishida, Taichi; Matsumae, Tomohiro

33

Carbon dioxide sensor  

DOEpatents

The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)

2011-11-15

34

The Change in Carbon Dioxide Levels  

NSDL National Science Digital Library

In this lesson students discover that ice cores can help us learn not only the temperature of the Earth in times past, but also the amount of Carbon Dioxide trapped in the air bubbles in the ice. This activity uses as source data a plot of each versus time, and asks the students to plot the Temperature variable versus the other variable which is the Carbon Dioxide content. Students can fit the data to a line y = mx + b to see how changes in Temperature and related to changes in Carbon Dioxide. After they make a graph of Carbon Dioxide concentration as a function of time, they will learn about linear trends in the data, as well as the annual variation of Carbon Dioxide and will then predict the level of Carbon Dioxide in a future year from the data.

35

Carbon Dioxide Removal  

NSDL National Science Digital Library

In this experiment using sprigs of Elodea, learners will observe a natural process that removes carbon dioxide (CO2) from Earth's atmosphere. This process is a part of the carbon cycle and results in temperature suitable for life. Note: this experiment requires that learners make observations an hour or the next day after they set up the materials.

2012-12-26

36

The Development of Models for Carbon Dioxide Reduction Technologies for Spacecraft Air Revitalization  

NASA Technical Reports Server (NTRS)

Through the respiration process, humans consume oxygen (O2) while producing carbon dioxide (CO2) and water (H2O) as byproducts. For long term space exploration, CO2 concentration in the atmosphere must be managed to prevent hypercapnia. Moreover, CO2 can be used as a source of oxygen through chemical reduction serving to minimize the amount of oxygen required at launch. Reduction can be achieved through a number of techniques. NASA is currently exploring the Sabatier reaction, the Bosch reaction, and co- electrolysis of CO2 and H2O for this process. Proof-of-concept experiments and prototype units for all three processes have proven capable of returning useful commodities for space exploration. All three techniques have demonstrated the capacity to reduce CO2 in the laboratory, yet there is interest in understanding how all three techniques would perform at a system level within a spacecraft. Consequently, there is an impetus to develop predictive models for these processes that can be readily rescaled and integrated into larger system models. Such analysis tools provide the ability to evaluate each technique on a comparable basis with respect to processing rates. This manuscript describes the current models for the carbon dioxide reduction processes under parallel developmental efforts. Comparison to experimental data is provided were available for verification purposes.

Swickrath, Michael J.; Anderson, Molly

2012-01-01

37

The Development of Models for Carbon Dioxide Reduction Technologies for Spacecraft Air Revitalization  

NASA Technical Reports Server (NTRS)

Through the respiration process, humans consume oxygen (O2) while producing carbon dioxide (CO2) and water (H2O) as byproducts. For long term space exploration, CO2 concentration in the atmosphere must be managed to prevent hypercapnia. Moreover, CO2 can be used as a source of oxygen through chemical reduction serving to minimize the amount of oxygen required at launch. Reduction can be achieved through a number of techniques. The National Aeronautics and Space Administration (NASA) is currently exploring the Sabatier reaction, the Bosch reaction, and co-electrolysis of CO2 and H2O for this process. Proof-of-concept experiments and prototype units for all three processes have proven capable of returning useful commodities for space exploration. While all three techniques have demonstrated the capacity to reduce CO2 in the laboratory, there is interest in understanding how all three techniques would perform at a system-level within a spacecraft. Consequently, there is an impetus to develop predictive models for these processes that can be readily re-scaled and integrated into larger system models. Such analysis tools provide the ability to evaluate each technique on a comparable basis with respect to processing rates. This manuscript describes the current models for the carbon dioxide reduction processes under parallel developmental e orts. Comparison to experimental data is provided were available for veri cation purposes.

Swickrath, Michael J.; Anderson, Molly

2011-01-01

38

Carbon Dioxide Exercise  

NSDL National Science Digital Library

In this activity, students work in groups, plotting carbon dioxide concentrations over time on overheads and estimating the rate of change over five years. Stacked together, the overheads for the whole class show an increase on carbon dioxide over five years and annual variation driven by photosynthesis. This exercise enables students to practice basic quantitative skills and understand how important sampling intervals can be when studying changes over time. A goal is to see how small sample size may give incomplete picture of data.

Richardson, Randy; Collection, Serc -.

39

Air-sea exchange of carbon dioxide in ocean margins: A province-based synthesis  

Microsoft Academic Search

In determining global sea-to-air CO2 flux from measurements or models, the ocean margin has not been resolved from the land or the open ocean. Recent studies have indicated that shelves can be either a large sink or a source for atmospheric CO2. This CO2 sink\\/source term may substantially alter our current view of the global carbon budget for land and

Wei-Jun Cai; Minhan Dai; Yongchen Wang

2006-01-01

40

Out of thin air: sensory detection of oxygen and carbon dioxide.  

PubMed

Oxygen (O?) and carbon dioxide (CO?) levels vary in different environments and locally fluctuate during respiration and photosynthesis. Recent studies in diverse animals have identified sensory neurons that detect these external variations and direct a variety of behaviors. Detection allows animals to stay within a preferred environment as well as identify potential food or dangers. The complexity of sensation is reflected in the fact that neurons compartmentalize detection into increases, decreases, and short-range and long-range cues. Animals also adjust their responses to these prevalent signals in the context of other cues, allowing for flexible behaviors. In general, the molecular mechanisms for detection suggest that sensory neurons adopted ancient strategies for cellular detection and coupled them to brain activity and behavior. This review highlights the multiple strategies that animals use to extract information about their environment from variations in O? and CO?. PMID:21262460

Scott, Kristin

2011-01-27

41

Easily regenerable solid adsorbents based on polyamines for carbon dioxide capture from the air.  

PubMed

Adsorbents prepared easily by impregnation of fumed silica with polyethylenimine (PEI) are promising candidates for the capture of CO2 directly from the air. These inexpensive adsorbents have high CO2 adsorption capacity at ambient temperature and can be regenerated in repeated cycles under mild conditions. Despite the very low CO2 concentration, they are able to scrub efficiently all CO2 out of the air in the initial hours of the experiments. The influence of parameters such as PEI loading, adsorption and desorption temperature, particle size, and PEI molecular weight on the adsorption behavior were investigated. The mild regeneration temperatures required could allow the use of waste heat available in many industrial processes as well as solar heat. CO2 adsorption from the air has a number of applications. Removal of CO2 from a closed environment, such as a submarine or space vehicles, is essential for life support. The supply of CO2-free air is also critical for alkaline fuel cells and batteries. Direct air capture of CO2 could also help mitigate the rising concerns about atmospheric CO2 concentration and associated climatic changes, while, at the same time, provide the first step for an anthropogenic carbon cycle. PMID:24644023

Goeppert, Alain; Zhang, Hang; Czaun, Miklos; May, Robert B; Prakash, G K Surya; Olah, George A; Narayanan, S R

2014-05-01

42

Carbon Dioxide Laser Guidelines  

PubMed Central

The carbon dioxide (CO2) laser is a versatile tool that has applications in ablative lasing and caters to the needs of routine dermatological practice as well as the aesthetic, cosmetic and rejuvenation segments. This article details the basics of the laser physics as applicable to the CO2 laser and offers guidelines for use in many of the above indications. PMID:20808594

Krupa Shankar, DS; Chakravarthi, M; Shilpakar, Rachana

2009-01-01

43

Bench Remarks: Carbon Dioxide.  

ERIC Educational Resources Information Center

Discusses the properties of carbon dioxide in its solid "dry ice" stage. Suggests several demonstrations and experiments that use dry ice to illustrate Avogadro's Law, Boyle's Law, Kinetic-Molecular Theory, and the effects of dry ice in basic solution, in limewater, and in acetone. (TW)

Bent, Henry A.

1987-01-01

44

Carbon Dioxide Increases  

NSDL National Science Digital Library

In this problem set, learners will analyze the Keeling Curve showing carbon dioxide concentration in the atmosphere since 1985 to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

45

Atmospheric Carbon Dioxide  

NSDL National Science Digital Library

This figure, the famous Keeling Curve, shows the history of atmospheric carbon dioxide concentrations as directly measured at Mauna Loa, Hawaii. This curve is an essential piece of evidence that shows the increased greenhouse gases that cause recent increases in global temperatures.

Robert A. Rohde

46

Air plasma gasification of RDF as a prospective method for reduction of carbon dioxide emission  

NASA Astrophysics Data System (ADS)

Waste disposal dumps are one of sources of carbonic gas penetration in the atmosphere. The waste is treated into RDF (refuse-derived fuel) and used in boilers for electric power or heat generation for decrease in carbonic gas emissions in the atmosphere. In industry power stations on the basis of the combined cycle have the highest efficiency of burning. The paper deals with the application of an air-plasma gasifier using the down draft scheme of RDF transformation into synthesis gas, which afterwards can be used in the combined cycle. Results of calculations of the process characteristics for various RDF compositions are presented. The advantage of the plasma method in comparison with autothermal one is shown. Experimental data are shown.

Bratsev, A. N.; Kumkova, I. I.; Kuznetsov, V. A.; Popov, V. E.; Shtengel', S. V.; Ufimtsev, A. A.

2011-03-01

47

Electrochemically regenerable carbon dioxide absorber  

NASA Technical Reports Server (NTRS)

Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

1979-01-01

48

Chemical Extraction of Carbon Dioxide From Air: A Strategy to Avoid Climate Change and Sustain Fossil Energy?  

NASA Astrophysics Data System (ADS)

Fossil energy use has benefited humankind but also threatens our environment. It has increased atmospheric carbon dioxide (CO2) levels from 280 ppm to 370 ppm, over the past century. This rise has been linked to with observed ocean acidification and global warming. Projections indicate that atmospheric CO2 could reach 540 to 970 ppm in 2100, with significant effects on our earth system. Given that fossil fuels are plentiful, cost-effective, and energy rich their use will be limited by our ability to mitigate their environmental impact. Carbon management provides potential solutions to this. Current approaches to manage carbon focus on capturing CO2 from large point sources such as power plants. They are limited because they fail to address emissions from transportation and the myriad of dispersed sources that amount to about half of all emissions. To solve this problem we have proposed and are developing direct CO2 extraction from air as a means to capture emissions from all sources [1-3]. It preserves our fuel distribution and transportation systems, and in principle could allow us to restore CO2 to pre-industrial levels. Our concept utilizes atmospheric circulation to capture CO2 directly from the dilute stream in air (370 ppm) by binding it to an adsorbent. Subsequent heating releases the bound CO2 as a pure stream suitable for permanent sequestration. For example, this cycle is favorable for Ca(OH)2 which reacts rapidly with CO2 to form CaCO3. The heat to recover CO2 from CaCO3 is 190 kJ/mole of C, less than half the heat of combustion of 500 kJ/ mole of C for coal. The scale of CO2 air-extraction plants to offset global emissions is large but could be manageable, and favorable relative to renewable sources. We report experiments on CO2 uptake by alkaline solutions as a function of pH, contact time, and mixing. Both active and passive mixing conditions are explored. Gram scale quantities of CO2 has been extracted from air by Ca(OH)2 and the product CaCO3 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.

Dubey, M. K.; Ziock, H.; Rueff, G.; Colman, J.; Smith, W. S.

2002-12-01

49

Mediterranean fruit flies: sterility and sexual competitiveness in the laboratory after treatment with gamma irradiation in air, carbon dioxide, helium, nitrogen, or partial vacuum  

Microsoft Academic Search

The level of sterility of males of Ceratitis capitata (Wiedemann) was similar when a given dose of gamma irradiation was applied to pupae in atmospheres of nitrogen, carbon dioxide or helium or in a partial vacuum. A dose of 10 krad in air was sufficient to produce 99.5 percent sterility in males; a dose of 16 krad was required to

K. Ohinata; M. Ashraf; E. J. Harris

1977-01-01

50

PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SUPERCRITICAL CARBON DIOXIDE-TREATED AND AIR-CLASSIFIED OAT BRAN CONCENTRATE MICROWAVE-IRRADIATED IN WATER OR ETHANOL AT VARYING TEMPERATURES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oat bran concentrate (OBC) was defatted with supercritical carbon dioxide (SCD), then microwave-irradiated at 50, 100 or 150 deg C for 10 min in water, 50% or 100% ethanol, and extract pH, soluble solids, phenolic content and antioxidant activity were analyzed. OBC was air-classified into five frac...

51

CARBON DIOXIDE FIXATION.  

SciTech Connect

Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

FUJITA,E.

2000-01-12

52

Modeling Carbon Dioxide Levels  

NSDL National Science Digital Library

In this activity students will explore levels of Carbon Dioxide ( C02) in the atmosphere over time. There is concern that levels of C02 are rising; and finding a good mathematical model for CO2 levels is an important part of determining if this is attributable to human technology. Students draw a scatter plot, choose two points to create a linear model for the data, then use the model to make predictions.

2009-01-01

53

High resolution measurements of methane and carbon dioxide in surface waters over a natural seep reveal dynamics of dissolved phase air-sea flux.  

PubMed

Marine hydrocarbon seeps are sources of methane and carbon dioxide to the ocean, and potentially to the atmosphere, though the magnitude of the fluxes and dynamics of these systems are poorly defined. To better constrain these variables in natural environments, we conducted the first high-resolution measurements of sea surface methane and carbon dioxide concentrations in the massive natural seep field near Coal Oil Point (COP), California. The corresponding high resolution fluxes were calculated, and the total dissolved phase air-sea fluxes over the surveyed plume area (?363 km(2)) were 6.66 × 10(4) to 6.71 × 10(4) mol day(-1) with respect to CH4 and -6.01 × 10(5) to -5.99 × 10(5) mol day(-1) with respect to CO2. The mean and standard deviation of the dissolved phase air-sea fluxes of methane and carbon dioxide from the contour gridding analysis were estimated to be 0.18 ± 0.19 and -1.65 ± 1.23 mmol m(-2) day(-1), respectively. This methane flux is consistent with previous, lower-resolution estimates and was used, in part, to conservatively estimate the total area of the dissolved methane plume at 8400 km(2). The influx of carbon dioxide to the surface water refutes the hypothesis that COP seep methane appreciably influences carbon dioxide dynamics. Seeing that the COP seep field is one of the biggest natural seeps, a logical conclusion could be drawn that microbial oxidation of methane from natural seeps is of insufficient magnitude to change the resulting plume area from a sink of atmospheric carbon dioxide to a source. PMID:25083936

Du, Mengran; Yvon-Lewis, Shari; Garcia-Tigreros, Fenix; Valentine, David L; Mendes, Stephanie D; Kessler, John D

2014-09-01

54

Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide  

SciTech Connect

Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction.

Schilling, J.B.

1997-09-01

55

Carbon dioxide sequestration by mineral carbonation  

Microsoft Academic Search

The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals

W. J. J. Huijgen; R. N. J. Comans

2007-01-01

56

Carbon Dioxide Reduction Through Urban Forestry  

E-print Network

Carbon Dioxide Reduction Through Urban Forestry: Guidelines for Professional and Volunteer Tree; Simpson, James R. 1999. Carbon dioxide reduction through urban forestry of Agriculture; 237 p. Carbon dioxide reduction through urban forestry--Guidelines for professional and volunteer

Standiford, Richard B.

57

Carbon dioxide and climate  

SciTech Connect

Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

Not Available

1990-10-01

58

Coral reefs and carbon dioxide  

SciTech Connect

This commentary argues the conclusion from a previous article, which investigates diurnal changes in carbon dioxide partial pressure and community metabolism on coral reefs, that coral `reefs might serve as a sink, not a source, for atmospheric carbon dioxide.` Commentaries from two groups are given along with the response by the original authors, Kayanne et al. 27 refs.

Buddemeier, R.W. [Kansas Geological Survey, Lawrence, KS (United States)

1996-03-01

59

SOIL AIR CARBON DIOXIDE CONCENTRATIONS IN A NEW ENGLAND SPRUCE-FIR FORESTS  

EPA Science Inventory

Research and modeling efforts to evaluate soil-soil solution chemical interactions must take into account solution equilibria with soil air CO2. Measurements of soil air CO2 and soil temperature were made in the major horizons of a forest soil in eastern Maine through the 1985 gr...

60

Nondestructive natural gas hydrate recovery driven by air and carbon dioxide  

PubMed Central

Current technologies for production of natural gas hydrates (NGH), which include thermal stimulation, depressurization and inhibitor injection, have raised concerns over unintended consequences. The possibility of catastrophic slope failure and marine ecosystem damage remain serious challenges to safe NGH production. As a potential approach, this paper presents air-driven NGH recovery from permeable marine sediments induced by simultaneous mechanisms for methane liberation (NGH decomposition) and CH4-air or CH4-CO2/air replacement. Air is diffused into and penetrates NGH and, on its surface, forms a boundary between the gas and solid phases. Then spontaneous melting proceeds until the chemical potentials become equal in both phases as NGH depletion continues and self-regulated CH4-air replacement occurs over an arbitrary point. We observed the existence of critical methane concentration forming the boundary between decomposition and replacement mechanisms in the NGH reservoirs. Furthermore, when CO2 was added, we observed a very strong, stable, self-regulating process of exchange (CH4 replaced by CO2/air; hereafter CH4-CO2/air) occurring in the NGH. The proposed process will work well for most global gas hydrate reservoirs, regardless of the injection conditions or geothermal gradient. PMID:25311102

Kang, Hyery; Koh, Dong-Yeun; Lee, Huen

2014-01-01

61

Nondestructive natural gas hydrate recovery driven by air and carbon dioxide  

NASA Astrophysics Data System (ADS)

Current technologies for production of natural gas hydrates (NGH), which include thermal stimulation, depressurization and inhibitor injection, have raised concerns over unintended consequences. The possibility of catastrophic slope failure and marine ecosystem damage remain serious challenges to safe NGH production. As a potential approach, this paper presents air-driven NGH recovery from permeable marine sediments induced by simultaneous mechanisms for methane liberation (NGH decomposition) and CH4-air or CH4-CO2/air replacement. Air is diffused into and penetrates NGH and, on its surface, forms a boundary between the gas and solid phases. Then spontaneous melting proceeds until the chemical potentials become equal in both phases as NGH depletion continues and self-regulated CH4-air replacement occurs over an arbitrary point. We observed the existence of critical methane concentration forming the boundary between decomposition and replacement mechanisms in the NGH reservoirs. Furthermore, when CO2 was added, we observed a very strong, stable, self-regulating process of exchange (CH4 replaced by CO2/air; hereafter CH4-CO2/air) occurring in the NGH. The proposed process will work well for most global gas hydrate reservoirs, regardless of the injection conditions or geothermal gradient.

Kang, Hyery; Koh, Dong-Yeun; Lee, Huen

2014-10-01

62

Nondestructive natural gas hydrate recovery driven by air and carbon dioxide.  

PubMed

Current technologies for production of natural gas hydrates (NGH), which include thermal stimulation, depressurization and inhibitor injection, have raised concerns over unintended consequences. The possibility of catastrophic slope failure and marine ecosystem damage remain serious challenges to safe NGH production. As a potential approach, this paper presents air-driven NGH recovery from permeable marine sediments induced by simultaneous mechanisms for methane liberation (NGH decomposition) and CH?-air or CH?-CO?/air replacement. Air is diffused into and penetrates NGH and, on its surface, forms a boundary between the gas and solid phases. Then spontaneous melting proceeds until the chemical potentials become equal in both phases as NGH depletion continues and self-regulated CH4-air replacement occurs over an arbitrary point. We observed the existence of critical methane concentration forming the boundary between decomposition and replacement mechanisms in the NGH reservoirs. Furthermore, when CO? was added, we observed a very strong, stable, self-regulating process of exchange (CH? replaced by CO?/air; hereafter CH?-CO?/air) occurring in the NGH. The proposed process will work well for most global gas hydrate reservoirs, regardless of the injection conditions or geothermal gradient. PMID:25311102

Kang, Hyery; Koh, Dong-Yeun; Lee, Huen

2014-01-01

63

Chemical Extraction of Carbon Dioxide From Air: A Strategy to Avoid Climate Change and Sustain Fossil Energy?  

Microsoft Academic Search

Fossil energy use has benefited humankind but also threatens our environment. It has increased atmospheric carbon dioxide (CO2) levels from 280 ppm to 370 ppm, over the past century. This rise has been linked to with observed ocean acidification and global warming. Projections indicate that atmospheric CO2 could reach 540 to 970 ppm in 2100, with significant effects on our

M. K. Dubey; H. Ziock; G. Rueff; J. Colman; W. S. Smith

2002-01-01

64

Carbon Dioxide and Ionic Liquid Refrigerants: Compact, Efficient Air Conditioning with Ionic Liquid-Based Refrigerants  

SciTech Connect

BEETIT Project: Notre Dame is developing an air-conditioning system with a new ionic liquid and CO2 as the working fluid. Synthetic refrigerants used in air conditioning and refrigeration systems are potent GHGs and can trap 1,000 times more heat in the atmosphere than CO2 alone—making CO2 an attractive alternative for synthetic refrigerants in cooling systems. However, operating cooling systems with pure CO2 requires prohibitively high pressures and expensive hardware. Notre Dame is creating a new fluid made of CO2 and ionic liquid that enables the use of CO2 at low pressures and requires minimal changes to existing hardware and production lines. This new fluid also produces no harmful emissions and can improve the efficiency of air conditioning systems— enabling new use of CO2 as a refrigerant in cooling systems.

None

2010-10-01

65

Geologic Sequestration of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Geologic sequestration of carbon dioxide has emerged as one of the most promising options for making deep cuts in carbon dioxide emissions. Geologic sequestration involves the two-step process of first capturing carbon dioxide by separating it from stack emissions, followed by injection and long term storage in deep geologic formations. Sedimentary basins, including depleted oil and gas reservoirs, deep unminable coal seams, and brine-filled formations, provide the most attractive storage reservoirs. Over the past few years significant advances have been made in this technology, including development of simulation models and monitoring systems, implementation of commercial scale demonstration projects, and investigation of natural and industrial analogues for geologic storage of carbon dioxide. While much has been accomplished in a short time, there are many questions that must be answered before this technology can be employed on the scale needed to make significant reductions in carbon dioxide emissions. Questions such as how long must the carbon dioxide remain underground, to what extent will geochemical reactions completely immobilize the carbon dioxide, what can be done in the event that a storage site begins to leak at an unacceptable rate, what is the appropriate risk assessment, regulatory and legal framework, and will the public view this option favorably? This paper will present recent advances in the scientific and technological underpinnings of geologic sequestration and identify areas where additional information is needed.

Benson, S. M.

2003-04-01

66

Penetration Characteristics of Air, Carbon Dioxide and Helium Transverse Sonic Jets in Mach 5 Cross Flow  

PubMed Central

An experimental investigation of sonic air, CO2 and Helium transverse jets in Mach 5 cross flow was carried out over a flat plate. The jet to freestream momentum flux ratio, J, was kept the same for all gases. The unsteady flow topology was examined using high speed schlieren visualisation and PIV. Schlieren visualisation provided information regarding oscillating jet shear layer structures and bow shock, Mach disc and barrel shocks. Two-component PIV measurements at the centreline, provided information regarding jet penetration trajectories. Barrel shocks and Mach disc forming the jet boundary were visualised/quantified also jet penetration boundaries were determined. Even though J is kept the same for all gases, the penetration patterns were found to be remarkably different both at the nearfield and the farfield. Air and CO2 jet resulted similar nearfield and farfield penetration pattern whereas Helium jet spread minimal in the nearfield. PMID:25494348

Erdem, Erinc; Kontis, Konstantinos; Saravanan, Selvaraj

2014-01-01

67

Photosynthesis and growth responses of mustard (Brassica juncea L. cv Pusa Bold) plants to free air carbon dioxide enrichment (FACE).  

PubMed

Increased atmospheric [CO2] is likely to affect photosynthesis, plant growth, and yield potential of plants. Mustard (Brassica juncea L.) is an important oil seed crop that is widely grown in India. Therefore, the impact of elevated [CO2] (585 ?mol mol(-1)) on pigment and protein content, chlorophyll a fluorescence, photosynthetic electron transport reactions, CO2 assimilation, biomass production, and seed yield potential was measured in B. juncea cv Pusa Bold, grown inside free air carbon dioxide enrichment (FACE) rings installed on the campus of Jawaharlal Nehru University, New Delhi, India. Plants were grown for three consecutive winter seasons (2010-2013), in ambient (385 ?mol mol(-1)) or elevated [CO2], in field conditions. Elevated [CO2] had no significant effect on the minimal chlorophyll fluorescence (F 0), while the quantum efficiency of Photosystem II, measured as variable fluorescence (F v?=?F m-F 0) to maximum fluoresence (F m), increased by 3 %. Electron transport rate, photosystem I, photosystem II, and whole chain electron transport rates increased by 8 % in elevated [CO2]. However, the net photosynthesis rate increased by ?50 % in three growing seasons under elevated [CO2] condition. The stomatal conductance and transpiration rate decreased resulting in higher photosynthetic water use efficiency. The photosynthesizing surface, i.e., leaf area index substantially increased leading to higher biomass and seed yield under elevated [CO2] condition. Acclimatory downregulation of photosynthesis and plant productivity was not observed in three consecutive growing years suggesting that in the absence of nutrient limitation, B. juncea is highly responsive to elevated CO2 whose yield potential shall increase in changing climatic conditions. PMID:25471475

Ruhil, Kamal; Sheeba; Ahmad, Altaf; Iqbal, Muhammad; Tripathy, Baishnab C

2014-12-01

68

Reducing carbon dioxide to products  

DOEpatents

A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

2014-09-30

69

NASA Satellite Sees Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will analyze a map of atmospheric carbon dioxide derived from satellite data. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

70

Carbon Dioxide and Ocean Acidification  

NSDL National Science Digital Library

Demonstrates the affect of increased dissolved carbon dioxide on water pH using a cheap, non-toxic acid/base indicator. Students bubble breath through a straw into red cabbage juice and note the color change.

Chris Lewis

71

Pressurized Fuel\\/Air Operated Solid Oxide Fuel Cell Combined Carbon-Dioxide-Capturing High-Performance Power Generation System  

Microsoft Academic Search

The authors recently proposed a solid oxide fuel cell (SOFC) and closed-cycle MHD combined carbon-dioxide-capturing high-performance power generation system using pure oxygen as the oxidant. This combined system can make the best use of the merit of pure oxygen combustion, while its demerit of efficiency deterioration by large required power for oxygen generation still remains. In the present study, the

Yoshitaka Inui; Taichi Ishida; Tomohiro Matsumae

2003-01-01

72

Recuperative supercritical carbon dioxide cycle  

DOEpatents

A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

2014-11-18

73

Estimating uncertainty of the WMO mole fraction scale for carbon dioxide in air  

NASA Astrophysics Data System (ADS)

The current WMO CO2 Mole Fraction Scale consists of a set of 15 CO2-in-air primary standard calibration gases ranging in CO2 mole fraction from 250 to 520 ?mol mol-1. Since the WMO CO2 Expert Group transferred responsibility for maintaining the WMO Scale from the Scripps Institution of Oceanography (SIO) to the Climate Monitoring and Diagnostics Laboratory (CMDL) in 1995, the 15 WMO primary standards have been calibrated, first at SIO and then at regular intervals, between 1 and 2 years, by the CMDL manometric system. The uncertainty of the 15 primary standards was estimated to be 0.069 ?mol mol-1 (one-sigma) in the absolute sense. Manometric calibrations results indicate that there is no evidence of overall drift of the Primaries from 1996 to 2004. In order to lengthen the useful life of the Primary standards, CMDL has always transferred the scale via NDIR analyzers to the secondary standards. The uncertainties arising from the analyzer random error and the propagation error due to the uncertainty of the reference gas mole fraction are discussed. Precision of NDIR transfer calibrations was about 0.014 ?mol mol-1 from 1979 to present. Propagation of the uncertainty was calculated theoretically. In the case of interpolation the propagation error was estimated to be between 0.06 and 0.07 ?mol mol-1 when the Primaries were used as the reference gases via NDIR transfer calibrations. The CMDL secondary standard calibrations are transferred via NDIR analyzers to the working standards, which are used routinely for measuring atmospheric CO2 mole fraction in the WMO Global Atmosphere Watch monitoring program. The uncertainty of the working standards was estimated to be 0.071 ?mol mol-1 in the one-sigma absolute scale. Consistency among the working standards is determined by the random errors of downward transfer calibrations at each level and is about 0.02 ?mol mol-1. For comparison with an independent absolute scale, the five gravimetric standards from the National Institute for the Environmental Studies (NIES) in Tsukuba, Japan, ranging in CO2 mole fraction from 350 to 390 ?mol mol-1 have been calibrated relative to the CMDL secondary standards. The average and standard deviation of the differences between the NIES gravimetric and CMDL analyzed CO2 mole fraction are 0.004 ± 0.03 ?mol mol-1.

Zhao, Cong Long; Tans, Pieter P.

2006-04-01

74

Creation and Propagation of the WMO Mole Fraction Scale for Carbon Dioxide in Air  

NASA Astrophysics Data System (ADS)

The atmospheric burden of CO2 has been monitored at the Mauna Loa observatory on Hawaii for half a century, and since then the observing system has been expanded to many sites worldwide. At present, non-dispersive infrared (NDIR) analyzers offer the most robust and precise method of CO2 quantification. However, this technique requires very accurately calibrated standard reference gases. The current WMO (World Meteorological Organization) CO2 Mole Fraction Scale consists of a set of fifteen CO2-in-air primary standard calibration gases ranging in CO2 mole fraction from 250 to 520 micromol/mol. Since the WMO CO2 Expert Group transferred responsibility for maintaining the WMO Scale from the Scripps Institute of Oceanography (SIO) to the Earth System Research Laboratory (ESRL) in 1995, the fifteen WMO primary standards have been calibrated, first at SIO and then at regular intervals, between one and two years, by the ESRL manometric system. The uncertainty of the 15 primary standards was estimated to be 0.069 micromol/mol in the absolute sense. Manometric calibrations results indicate that there is no evidence of overall drift of the Primaries from 1996 to 2008. In order to lengthen the useful life of the Primary standards, ESRL has always transferred the scale via NDIR analyzers to the secondary standards. The uncertainties arising from the analyzer random error and the propagation error due to the uncertainty of the reference gas mole fraction are discussed. Precision of NDIR transfer calibrations was about 0.013 micromol/mol from 1979 to present. Propagation of the uncertainty was calculated theoretically. In the case of interpolation the propagation error was estimated to be between 0.06 and 0.07 micromol/mol when the Primaries were used as the reference gases via NDIR transfer calibrations. The ESRL secondary standard calibrations are transferred via NDIR analyzers to the working standards, which are used routinely for measuring atmospheric CO2 mole fraction in the WMO Global Atmosphere Watch monitoring program. The uncertainty of the working standards was estimated to be 0.071 micromol/mol in the one-sigma absolute scale. For comparison with an independent absolute scale, the five gravimetric standards from the National Institute for the Environmental Studies (NIES) in Tsukuba of Japan ranging in CO2 mole fraction from 350 to 390 micromol/mol have been calibrated relative to the ESRL secondary standards. The average and standard deviation of the differences between the NIES gravimetric and ESRL analyzed CO2 mole fraction are 0.004±0.03 micromol/mol.

Zhao, C.; Tans, P.

2009-04-01

75

[An autopsy case of carbon dioxide intoxication].  

PubMed

A 44-year-old male, engaged in the transportation of dry ice, was found dead on the floor of the freezer of his refrigerator car which was parked in front of the place where he was scheduled to make a delivery. Autopsy was performed to investigate the cause of death. Apart from the signs of acute death, no other significant findings were obtained, either macro or microscopically; carbon dioxide poisoning was thus strongly suspected. We created a simulation experiment by using the refrigerator car to reproduce the events of the accident. The oxygen concentration in the freezer was 21.0% as indicated by oxygen sensors, but decreased to 17.1-17.4% when the engine was stopped. This decrease in oxygen concentration supposedly results from the production of carbon dioxide by the vaporization of dry ice. Carbon dioxide concentration in the air could be calculated from the change in the oxygen concentration in the closed space of the freezer. The concentration was assessed at 17.1-18.6%. An oxygen concentration of 17.1-17.4% does not of itself cause serious hypoxia, but a carbon dioxide concentration of 17.1-18.6% probably causes serious intoxication, because this value is beyond that of intoxication levels published in references. Therefore, we concluded that the cause of death in this case was carbon dioxide intoxication. PMID:9545760

Yamazaki, M; Islam, M N; Ogura, Y; Honda, K; Tsuchihashi, H; Nishioka, H

1997-12-01

76

Magnesite disposal of carbon dioxide  

SciTech Connect

In this paper we report our progress on developing a method for carbon dioxide disposal whose purpose it is to maintain coal energy competitive even is environmental and political pressures will require a drastic reduction in carbon dioxide emissions. In contrast to most other methods, our approach is not aiming at a partial solution of the problem, or at buying time for phasing out fossil energy. Instead, its purpose is to obtain a complete and economic solution of the problem, and thus maintain access to the vast fossil energy reservoir. A successful development of this technology would guarantee energy availability for many centuries even if world economic growth the most optimistic estimates that have been put forward. Our approach differs from all others in that we are developing an industrial process which chemically binds the carbon dioxide in an exothermic reaction into a mineral carbonate that is thermodynamically stable and environmentally benign.

Lackner, K.S.; Butt, D.P.; Wendt, C.H.

1997-08-01

77

Carbon Dioxide Information Analysis Center (CDIAC)  

NSDL National Science Digital Library

Based at Oak Ridge National Laboratories in Tennessee, this Website is the US Department of Energy's "primary global-change data and information analysis center" and is a central source for many Carbon Dioxide-related resources. Among those resources are several we have reviewed, for example, the Catalog of Databases and Reports (reviewed in the June 24, 1998 Scout Report for Science & Engineering) and Carbon Dioxide Emission Estimates (reviewed in the March 4, 1998 Scout Report for Science & Engineering). The CDIAC site offers a wealth of information, including "records of the concentrations of carbon dioxide and other radiatively active gases in the atmosphere; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; emissions of carbon dioxide to the atmosphere; long-term climate trends; the effects of elevated carbon dioxide on vegetation; and the vulnerability of coastal areas to rising sea level." To get a feel for the research summaries and data available at the CDIAC site, see the Products section (describes the research projects associated with CDIAC as well as links to those data sets); the New section (offers a hyperlinked list of new data products); the Top 10 section (offers a hyperlinked list of Frequently Requested Global Change Products); or any of the specific project sections: FACE (Free Air CO2 Enrichment), NARSTO (a non-binding, tri-national, public/private alliance), OCEANS (Survey of CO2 in the Oceans), or AmeriFlux (long-term CO2 flux measurements of the Americas). This is an outstanding resource for those seeking global data (or research summaries) on the status of carbon dioxide in several components of the earth's ecosystems.

78

Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures  

Microsoft Academic Search

The influence of irradiance, CO[sub 2] concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of Alstroemeria Jacqueline' was studied. At ambient CO[sub 2], leaf net photosynthesis was maximum at irradiances above 600 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] photosynthetically active radiation (PAR), while whole-plant NCER required 1,200 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] PAR to be saturated.

E. D. Leonardos; M. J. Tsujita; B. Grodzinski

1994-01-01

79

Carbon Dioxide - Our Common "Enemy"  

NASA Technical Reports Server (NTRS)

Health effects of brief and prolonged exposure to carbon dioxide continue to be a concern for those of us who manage this pollutant in closed volumes, such as in spacecraft and submarines. In both examples, considerable resources are required to scrub the atmosphere to levels that are considered totally safe for maintenance of crew health and performance. Defining safe levels is not a simple task because of many confounding factors, including: lack of a robust database on human exposures, suspected significant variations in individual susceptibility, variations in the endpoints used to assess potentially adverse effects, the added effects of stress, and the fluid shifts associated with micro-gravity (astronauts only). In 2007 the National Research Council proposed revised Continuous Exposure Guidelines (CEGLs) and Emergency Exposure Guidelines (EEGLs) to the U.S. Navy. Similarly, in 2008 the NASA Toxicology Group, in cooperation with another subcommittee of the National Research Council, revised Spacecraft Maximum Allowable Concentrations (SMACs). In addition, a 1000-day exposure limit was set for long-duration spaceflights to celestial bodies. Herein we examine the rationale for the levels proposed to the U.S. Navy and compare this rationale with the one used by NASA to set its limits. We include a critical review of previous studies on the effects of exposure to carbon dioxide and attempt to dissect out the challenges associated with setting fully-defensible limits. We also describe recent experiences with management of carbon dioxide aboard the International Space Station with 13 persons aboard. This includes the tandem operations of the Russian Vozduk and the U.S. Carbon Dioxide Removal System. A third removal system is present while the station is docked to the Shuttle spacecraft, so our experience includes the lithium hydroxide system aboard Shuttle for the removal of carbon dioxide. We discuss strategies for highly-efficient, regenerable removal of carbon dioxide that could meet the 1000-day SMAC of 0.5%, which would apply to long-duration voyages to Mars.

James, John T.; Macatangay, Ariel

2009-01-01

80

Carbon dioxide fluxes across the air-water interface and its impact on carbon availability in aquatic systems  

SciTech Connect

Diffusion of CO{sub 2} across the air-water interface was analyzed with a model that simulates both transport and reaction of CO{sub 2} in a stagnant boundary layer. The atmospheric C influx was determined in relation to several environmental variables: pH, total dissolved inorganic C, temperature, and the thickness of the stagnant boundary layer in relation to ambient windspeed. We used the model to calculate the atmospheric CO{sub 2} influx into experimental ditches for a period of 6 to 8 months, starting in early spring. Three of the six ditches were dominated by aquatic macrophytes and three by benthic algae. Each series received three levels of external N and P input. A comparison with net C assimilation during the same period, as estimated from continuous oxygen measurements, showed that, especially in the ditches dominated by submersed macrophytes, a sizable fraction of the C requirements during this period could have been obtained from atmospheric CO{sub 2}. In the ditches dominated by benthic algae, this fraction was considerably less, but nonetheless substantial, and was related to the level of N and P loading. Increased primary production due to enhanced external N and P loading increased the atmospheric C input due to the resultant higher pH values. The trophic state with respect to N and P and the availability of C are therefore interrelated. 25 refs., 8 figs., 5 tabs.

Portielje, R.; Lijklema, L. [Agricultural Univ., Wageningen (Netherlands)

1995-06-01

81

Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures  

SciTech Connect

The influence of irradiance, CO[sub 2] concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of Alstroemeria Jacqueline' was studied. At ambient CO[sub 2], leaf net photosynthesis was maximum at irradiances above 600 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] photosynthetically active radiation (PAR), while whole-plant NCER required 1,200 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] PAR to be saturated. Leaf and whole-plant NCERs were doubled under CO[sub 2] enrichment of 1,500 to 2,000 [mu]l CO[sub 2]/liter. Leaf and whole-plant NCERs declined as temperature increased from 20 to 35 C. Whereas the optimum temperature range for leaf net photosynthesis was 17 to 23 C, whole-plant NCER, even at high light and high CO[sub 2], declined above 12 C. Dark respiration of leaves and whole plants increased with a Q[sub 10] of [approx] 2 at 15 to 35 C. In an analysis of day effects, irradiance, CO[sub 2] concentration, and temperature contributed 58%, 23%, and 14%, respectively, to the total variation in NCER explained by a second-order polynomial model (R[sup 2] = 0.85). Interactions among the factors accounted for 4% of the variation in day C assimilation. The potential whole-plant growth rates during varying greenhouse day and night temperature regimes were predicted for short- and long-day scenarios. The data are discussed with the view of designing experiments to test the importance of C gain in supporting flowering and high yield during routine harvest of Alstroemeria plants under commercial greenhouse conditions.

Leonardos, E.D.; Tsujita, M.J.; Grodzinski, B. (Univ. of Guelph, Ontario (Canada). Dept. of Horticultural Science)

1994-11-01

82

Process for sequestering carbon dioxide and sulfur dioxide  

DOEpatents

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Maroto-Valer, M. Mercedes (State College, PA); Zhang, Yinzhi (State College, PA); Kuchta, Matthew E. (State College, PA); Andresen, John M. (State College, PA); Fauth, Dan J. (Pittsburgh, PA)

2009-10-20

83

Carbon dioxide transport over complex terrain  

USGS Publications Warehouse

The nocturnal transport of carbon dioxide over complex terrain was investigated. The high carbon dioxide under very stable conditions flows to local low-ground. The regional drainage flow dominates the carbon dioxide transport at the 6 m above the ground and carbon dioxide was transported to the regional low ground. The results show that the local drainage flow was sensitive to turbulent mixing associated with local wind shear.

Sun, J.; Burns, S.P.; Delany, A.C.; Oncley, S.P.; Turnipseed, A.; Stephens, B.; Guenther, A.; Anderson, D.E.; Monson, R.

2004-01-01

84

Carbon Dioxide - Sources and Sinks  

NSDL National Science Digital Library

In this lab activity, students use a chemical indicator (bromothymol blue) to detect the presence of carbon dioxide in animal and plant respiration and in the burning of fossil fuels and its absence in the products of plant photosynthesis. After completing the five parts of this activity, students compare the colors of the chemical indicator in each part and interpret the results in terms of the qualitative importance of carbon sinks and sources.

Universe, Windows T.

85

Photolytical Generation of Carbon Dioxide  

Microsoft Academic Search

Carbon dioxide has been found by Cassini VIMS throughout the Saturnian system in locations such as Iapetus' equator where the temperature is too high for it to remain as free ice for more than a few hundred years. We suggest that the 4.26 micron absorption feature found on Iapetus and Hyperion (that has been attributed to complexed CO2) is the

E. E. Palmer; R. H. Brown

2008-01-01

86

A correlation of optimal heat rejection pressures in transcritical carbon dioxide cycles  

E-print Network

A correlation of optimal heat rejection pressures in transcritical carbon dioxide cycles S.M. Liaoa) of transcritical carbon dioxide air-conditioning cycles. The analysis shows that the COP of the transcritical carbon dioxide cycle varies nonmonotonically with the heat rejection pressure; a maximum COP occurs

Zhao, Tianshou

87

Application of a high-efficiency cabin air filter for simultaneous mitigation of ultrafine particle and carbon dioxide exposures inside passenger vehicles.  

PubMed

Modern passenger vehicles are commonly equipped with cabin air filters but their filtration efficiency for ultrafine particle (UFP) is rather low. Although setting the vehicle ventilation system to recirculation (RC) mode can reduce in-cabin UFPs by ? 90%, passenger-exhaled carbon dioxide (CO2) can quickly accumulate inside the cabin. Using outdoor air (OA) mode instead can provide sufficient air exchange to prevent CO2 buildup, but in-cabin UFP concentrations would increase. To overcome this dilemma, we developed a simultaneous mitigation method for UFP and CO2 using high-efficiency cabin air (HECA) filtration in OA mode. Concentrations of UFP and other air pollutants were simultaneously monitored in and out of 12 different vehicles under 3 driving conditions: stationary, on local roadways, and on freeways. Under each experimental condition, data were collected with no filter, in-use original equipment manufacturer (OEM) filter, and two types of HECA filters. The HECA filters offered an average in-cabin UFP reduction of 93%, much higher than the OEM filters (? 50% on average). Throughout the measurements, the in-cabin CO2 concentration remained in the range of 620-930 ppm, significantly lower than the typical level of 2500-4000 ppm observed in the RC mode. PMID:24471775

Lee, Eon S; Zhu, Yifang

2014-02-18

88

In situ measurements of carbon dioxide in the winter Arctic vortex and at midlatitudes: An indicator of the age of stratospheric air  

SciTech Connect

The authors report measurements of the vertical distribution of the carbon dioxide mixing ratio in the lower and middle stratosphere. They were performed during a series of balloon flights over midlatitudes (44{degree}N) during different seasons and over high latitudes (68{degree}N) during winter in the time period from 1982 until 1990. CO{sub 2} was gas chromatographically determined in air samples collected by means of cryogenic whole-air samplers. The annual increase of the CO{sub 2} content of the mid-stratospheric air is comparable to the temporal CO{sub 2} trend in the troposphere. However, the stratospheric concentrations are lagging the tropospheric ones by a mean delay time of 5.6 {plus minus} 1.1 years. This delay time may be interpreted as the age of stratospheric air masses. It is determined by the efficiency of the transport processes that mix tropospheric air into the stratosphere. The CO{sub 2} observations during the last decade suggest that these processes have varied systematically with a time period of 3 to 5 years. A rather low age of 2.3 {plus minus} 0.3 years was derived from the most recent observations over midlatitudes in summer 1989 as well as in the Arctic region during the CHEOPS III Campaign in winter 1989/90.

Schmidt, U.; Khedim, A. (Forschungszentrum Juelich (West Germany))

1991-04-01

89

Passive colorimetric dosimeter tubes for ammonia, carbon monoxide, carbon dioxide, hydrogen sulfide, nitrogen dioxide, and sulfur dioxide  

SciTech Connect

Colorimetric, stain length, personal dosimeters operating by gas diffusion have been developed to determine worker exposure for up to an 8-h period for several inorganic airborne contaminants in the range of their threshold limit values. Length of stain, colorimetric dosimeters have been made for the detection of ammonia (NH/sub 3/), carbon monoxide (CO), carbon dioxide (CO/sub 2/), hydrogen sulfide (H/sub 2/S), nitrogen dioxide (NO/sub 2/), and sulfur dioxide (SO/sub 2/) in air. For each gas detection system, the sampler depends on the transfer of the gas by diffusion into a glass tube containing a colorimetric length of stain indicator. The stain length developed in a given period of time is compared to a calibration chart to determine, on the spot, the average gas concentration to which the dosimeter has been exposed. These dosimeters are known by the trade name Vapor Gard.

McKee, E.S.; Pritts, I.M.

1981-08-01

90

Passive colorimetric dosimeter tubes for ammonia, carbon monoxide, carbon dioxide, hydrogen sulfide, nitrogen dioxide and sulfur dioxide  

SciTech Connect

Colorimetric, stain length, personal dosimeters operating by gas diffusion have been developed to determine worker exposure for up to an eight-hour period for several inorganic airborne contaminants in the range of their Threshold Limit Values. Length of stain, colorimetric dosimeters have been made for the detection of ammonia (NH/sub 3/), carbon monoxide (CO), carbon dioxide (CO/sub 2/), hydrogen sulfide (H/sub 2/S), nitrogen dioxide (NO/sub 2/), and sulfur dioxide (SO/sub 2/) in air. For each gas detection system, the sampler depends on the transfer of the gas by diffusion into a glass tube containing a colorimetric length of stain indicator. The stain length developed in a given period of time is compared to a calibration chart to determine, on the spot, the average gas concentration to which the dosimeter has been exposed. These dosimeters are known by the trade name Vapor Gard.

McConnaughey, P.W.; McKee, E.S.; Pritts, I.M.

1985-07-01

91

Tethered catalysts for the hydration of carbon dioxide  

SciTech Connect

A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

2014-11-04

92

Carbon Dioxide Removal via Passive Thermal Approaches  

NASA Technical Reports Server (NTRS)

A paper describes a regenerable approach to separate carbon dioxide from other cabin gases by means of cooling until the carbon dioxide forms carbon dioxide ice on the walls of the physical device. Currently, NASA space vehicles remove carbon dioxide by reaction with lithium hydroxide (LiOH) or by adsorption to an amine, a zeolite, or other sorbent. Use of lithium hydroxide, though reliable and well-understood, requires significant mass for all but the shortest missions in the form of lithium hydroxide pellets, because the reaction of carbon dioxide with lithium hydroxide is essentially irreversible. This approach is regenerable, uses less power than other historical approaches, and it is almost entirely passive, so it is more economical to operate and potentially maintenance- free for long-duration missions. In carbon dioxide removal mode, this approach passes a bone-dry stream of crew cabin atmospheric gas through a metal channel in thermal contact with a radiator. The radiator is pointed to reject thermal loads only to space. Within the channel, the working stream is cooled to the sublimation temperature of carbon dioxide at the prevailing cabin pressure, leading to formation of carbon dioxide ice on the channel walls. After a prescribed time or accumulation of carbon dioxide ice, for regeneration of the device, the channel is closed off from the crew cabin and the carbon dioxide ice is sublimed and either vented to the environment or accumulated for recovery of oxygen in a fully regenerative life support system.

Lawson, Michael; Hanford, Anthony; Conger, Bruce; Anderson, Molly

2011-01-01

93

VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE FROM  

E-print Network

) were used to describe the properties of the pure substances. The vapor pressures of water and carbonVAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE the vapor-liquid equilibrium of water (between 323 and 573 K), carbon dioxide (between 230 and 290 K

94

Carbon dioxide review 1982  

SciTech Connect

The buildup of CO/sub 2/ is a reality, monitored with increasing precision since 1957 and inferred for much earlier dates. A statistical section gives the monitored values to 1980, as well as a review of a long series of measurements made at Mauna Loa by the pioneers of such monitoring, Charles D. Keeling, Robert B. Bacastow, and Timothy P. Whorf. The book discusses internal transport processes in the ocean, of ocean-atmosphere interaction, of the magnitude of forest and soil carbon wastage, of the future course of fossil-fuel consumption. Yet something else emerges, too: if the CO/sub 2/ buildup continues; if the big general circulation models are right about its impact on climate, and if we have not miscalculated the potential role of the oceans, then we face a climatic change in the next century and a half like nothing the post-glacial world, and hence civilized humanity, has seen.

Clark, W.C. (ed.)

1982-01-01

95

Solubility of Carbon Dioxide in Water.  

ERIC Educational Resources Information Center

Describes an activity measuring the amount of dissolved carbon dioxide in carbonated water at different temperatures. The amount of carbon dioxide is measured by the amount of dilute ammonia solution needed to produce a pH indicator color change. (PR)

Bush, Pat; And Others

1992-01-01

96

Carbon Dioxide Capture from Coal-Fired  

E-print Network

Carbon Dioxide Capture from Coal-Fired Power Plants: A Real Options Analysis May 2005 MIT LFEE 2005 are valued using the "real options" valuation methodology in an uncertain carbon dioxide (CO2) price support for the work was provided by the Carbon Sequestration Initiative. The authors acknowledge Linda Ye

97

Carbon Cycle: Exchanging Carbon Dioxide between the Atmosphere and Ocean  

NSDL National Science Digital Library

This lab investigates the exchange of carbon dioxide between the atmosphere and the ocean's surface. It is based on the fact that carbon dioxide dissolves in the ocean and provides the source of that plants and plankton living in the ocean rely on for photosynthesis. Students will discover that the amount of carbon dioxide the ocean can contain depends on the temperature of the water and its salinity (whether it is sea water or fresh water) and that cold water can hold more carbon dioxide in solution than warm water. They will observe that when carbon dioxide dissolves in water, it forms carbonic acid which makes the water acidic, and they will test for the acidity caused by the presence of dissolved carbon dioxide using Universal Indicator, which turns yellow when the solution is acidic. This activity tests whether sea water or fresh water absorbs more carbon dioxide.

98

The use of seawater as a carbon dioxide scrubbing medium for underwater life support  

SciTech Connect

Experimental evidence suggests that seawater could be used to scrub carbon dioxide form cabin air in underwater habitats. Seawater has the capacity to absorb carbon dioxide in quantities directly dependent on a number of variables, the most significant of which is the partial pressure of the carbon dioxide in the gas. The absorption capacities of freshwater and seawater are determined in this study in relation to the variables of carbon dioxide partial pressure, water temperature and pH for use in simple engineering design calculations. A conceptual carbon dioxide scrubber is proposed which involves the direct absorption of carbon dioxide in small concentrations in diffused air by a pressurized seawater tower. This conceptual design can potentially offer a low-energy seawater carbon dioxide scrubber to be externally or internally mounted on an underwater habitat.

Nuckols, M.L. [Naval Academy, Annapolis, MD (United States). Dept. of Naval Architecture, Ocean and Marine Engineering

1996-09-01

99

Development and Validation of a Novel Gas Analyzer for Simultaneous Measurements of Methane, Carbon Dioxide and Water Vapor in Ambient Air at 20 Hz  

NASA Astrophysics Data System (ADS)

Methane has increased significantly with human population levels. Pre-1750 ice core data indicates that pre- industrialization levels were about 700 ppbv, while current levels are over 1750 ppbv. In current budget estimates of atmospheric methane, major contributors include both natural (wetlands) and anthropogenic sources (energy, landfills, ruminants, biomass burning, rice agriculture). The strengths of these sources vary spatially and temporally. Estimates of emissions from wetlands are also uncertain due to the extreme variability of these ecosystems. Because methane lifetime is relatively long (8.4 years), atmospheric variations in concentration are small and accuracy in measurement is important for understanding spatial and temporal variability. Atmospheric concentrations of carbon dioxide and methane rose sharply in 2007. Global CO2 climbed by 0.6 percent, or 19 billion tons, in 2007. Methane increased by 27 million tons after nearly a decade with little or no increase. Atmospheric CO2 levels currently stand at 385 ppmv, or about 38 percent higher than pre- industrial levels and the rise in CO2 concentrations has been accelerating since the 1980s when annual increases were around 1.5 ppm per year. Last year the increase was 2.4 ppm. We report on the development, application and independent performance characterization of a novel gas analyzer based on cavity-enhanced laser absorption spectroscopy. The Analyzer provides simultaneous measurements of methane, carbon dioxide and water vapor in ambient air in the field for applications that require high data rates (eddy correlation flux), wide dynamic range (e.g., chamber flux and other applications with concentrations that are ten times typical ambient levels or higher) and highest accuracy (atmospheric monitoring stations). The Analyzer provides continuous measurements at data rates up to 20 Hz and with replicate precision of 1 ppbv for methane (1 second measurement time), 0.2 ppmv for carbon dioxide (1 second measurement time) and 100 ppmv for water vapor (1 second measurement time). The stability of the instrument allows for reliable averaging over longer periods for applications that require even higher accuracy and precision.

Gupta, M.; Owano, T.; Fellers, R.; Dong, F.; Baer, D.

2008-12-01

100

Estimated Carbon Dioxide Emissions in 2008: United States  

SciTech Connect

Flow charts depicting carbon dioxide emissions in the United States have been constructed from publicly available data and estimates of state-level energy use patterns. Approximately 5,800 million metric tons of carbon dioxide were emitted throughout the United States for use in power production, residential, commercial, industrial, and transportation applications in 2008. Carbon dioxide is emitted from the use of three major energy resources: natural gas, coal, and petroleum. The flow patterns are represented in a compact 'visual atlas' of 52 state-level (all 50 states, the District of Columbia, and one national) carbon dioxide flow charts representing a comprehensive systems view of national CO{sub 2} emissions. Lawrence Livermore National Lab (LLNL) has published flow charts (also referred to as 'Sankey Diagrams') of important national commodities since the early 1970s. The most widely recognized of these charts is the U.S. energy flow chart (http://flowcharts.llnl.gov). LLNL has also published charts depicting carbon (or carbon dioxide potential) flow and water flow at the national level as well as energy, carbon, and water flows at the international, state, municipal, and organizational (i.e. United States Air Force) level. Flow charts are valuable as single-page references that contain quantitative data about resource, commodity, and byproduct flows in a graphical form that also convey structural information about the system that manages those flows. Data on carbon dioxide emissions from the energy sector are reported on a national level. Because carbon dioxide emissions are not reported for individual states, the carbon dioxide emissions are estimated using published energy use information. Data on energy use is compiled by the U.S. Department of Energy's Energy Information Administration (U.S. EIA) in the State Energy Data System (SEDS). SEDS is updated annually and reports data from 2 years prior to the year of the update. SEDS contains data on primary resource consumption, electricity generation, and energy consumption within each economic sector. Flow charts of state-level energy usage and explanations of the calculations and assumptions utilized can be found at: http://flowcharts.llnl.gov. This information is translated into carbon dioxide emissions using ratios of carbon dioxide emissions to energy use calculated from national carbon dioxide emissions and national energy use quantities for each particular sector. These statistics are reported annually in the U.S. EIA's Annual Energy Review. Data for 2008 (US. EIA, 2010) was updated in August of 2010. This is the first presentation of a comprehensive state-level package of flow charts depicting carbon dioxide emissions for the United States.

Smith, C A; Simon, A J; Belles, R D

2011-04-01

101

The Carbon Dioxide Greenhouse: Is It Effective?  

NSDL National Science Digital Library

This activity allows students to compare the thermal properties of carbon dioxide with those of air, and can be extended to compare water vapor as well. Students discover that the gas which absorbs the most heat (infrared radiation) is the most effective greenhouse gas because in the atmosphere it would absorb more infrared coming from the surface of the Earth. This activity could be used as either a demonstration or a laboratory activity depending on the availability of equipment. Either a data logger is used to record the changing temperature of air and of carbon dioxide in plastic bottles as they are heated using electric lamps, and then allowed to cool, or if a data logger is not available, then thermometers can be used instead and monitored by students. The site contains teacher notes and instructions with a list of materials and a photograph showing the setup. It also has an introduction for the students and questions for them to answer along with a glossary.

102

46 CFR 131.817 - Carbon dioxide warning signs.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide warning signs. 131.817 ...and Emergency Equipment § 131.817 Carbon dioxide warning signs. Each entrance to a space storing carbon dioxide cylinders, a space...

2014-10-01

103

46 CFR 193.15-20 - Carbon dioxide storage.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide storage. 193.15-20...VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-20 Carbon dioxide storage. (a)...

2014-10-01

104

46 CFR 108.431 - Carbon dioxide systems: General.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide systems: General. 108.431...EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.431 Carbon dioxide systems: General. (a)...

2014-10-01

105

46 CFR 169.565 - Fixed carbon dioxide system.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Fixed carbon dioxide system. 169.565 Section 169...Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a) The number of pounds of carbon dioxide required for each space...

2014-10-01

106

46 CFR 196.37-8 - Carbon dioxide warning signs.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide warning signs. 196.37-8...Emergency Equipment, etc. § 196.37-8 Carbon dioxide warning signs. Each entrance to a space storing carbon dioxide cylinders, a space...

2014-10-01

107

46 CFR 108.626 - Carbon dioxide warning signs.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide warning signs. 108.626 ...Markings and Instructions § 108.626 Carbon dioxide warning signs. Each entrance to a space storing carbon dioxide cylinders, a space...

2014-10-01

108

46 CFR 78.47-11 - Carbon dioxide warning signs.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide warning signs. 78.47-11...Emergency Equipment, Etc. § 78.47-11 Carbon dioxide warning signs. Each entrance to a space storing carbon dioxide cylinders, a space...

2014-10-01

109

46 CFR 97.37-11 - Carbon dioxide warning signs.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide warning signs. 97.37-11...Emergency Equipment, Etc. § 97.37-11 Carbon dioxide warning signs. Each entrance to a space storing carbon dioxide cylinders, a space...

2014-10-01

110

49 CFR 179.102-1 - Carbon dioxide, refrigerated liquid.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide, refrigerated liquid. 179...114 and 120) § 179.102-1 Carbon dioxide, refrigerated liquid. (a) Tank cars used to transport carbon dioxide, refrigerated liquid...

2014-10-01

111

Silanediol-catalyzed carbon dioxide fixation.  

PubMed

Carbon dioxide is an abundant and renewable C1 source. However, mild transformations with carbon dioxide at atmospheric pressure are difficult to accomplish. Silanediols have been discovered to operate as effective hydrogen-bond donor organocatalysts for the atom-efficient conversion of epoxides to cyclic carbonates under environmentally friendly conditions. The reaction system is tolerant of a variety of epoxides and the desired cyclic carbonates are isolated in excellent yields. PMID:25328125

Hardman-Baldwin, Andrea M; Mattson, Anita E

2014-12-01

112

Carbon Dioxide for pH Control  

SciTech Connect

Cardox, the major supplier of carbon dioxide, has developed a diffuser to introduce carbon dioxide into a water volume as small bubbles to minimize reagent loss to the atmosphere. This unit is integral to several configurations suggested for treatment to control alkalinity in water streams.

Wagonner, R.C.

2001-08-16

113

Interglacials, Milankovitch Cycles, and Carbon Dioxide  

E-print Network

The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions.

Gerald E. Marsh

2010-02-11

114

CARBON DIOXIDE STORAGE IN PENNSYLVANIA PASTURES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Global warming, caused primarily by the burning of fossil fuels and the resulting increase in atmospheric greenhouse gasses such as carbon dioxide, is increasingly being recognized as a concern for the wellbeing of the planet. Agricultural practices that increase carbon dioxide storage in soil organ...

115

Encapsulated liquid sorbents for carbon dioxide capture.  

PubMed

Drawbacks of current carbon dioxide capture methods include corrosivity, evaporative losses and fouling. Separating the capture solvent from infrastructure and effluent gases via microencapsulation provides possible solutions to these issues. Here we report carbon capture materials that may enable low-cost and energy-efficient capture of carbon dioxide from flue gas. Polymer microcapsules composed of liquid carbonate cores and highly permeable silicone shells are produced by microfluidic assembly. This motif couples the capacity and selectivity of liquid sorbents with high surface area to facilitate rapid and controlled carbon dioxide uptake and release over repeated cycles. While mass transport across the capsule shell is slightly lower relative to neat liquid sorbents, the surface area enhancement gained via encapsulation provides an order-of-magnitude increase in carbon dioxide absorption rates for a given sorbent mass. The microcapsules are stable under typical industrial operating conditions and may be used in supported packing and fluidized beds for large-scale carbon capture. PMID:25652243

Vericella, John J; Baker, Sarah E; Stolaroff, Joshuah K; Duoss, Eric B; Hardin, James O; Lewicki, James; Glogowski, Elizabeth; Floyd, William C; Valdez, Carlos A; Smith, William L; Satcher, Joe H; Bourcier, William L; Spadaccini, Christopher M; Lewis, Jennifer A; Aines, Roger D

2015-01-01

116

Carbon dioxide sequestration by mineral carbonation  

SciTech Connect

Concerns about global warming caused by the increasing concentration of carbon dioxide and other greenhouse gases in the earth’s atmosphere have resulted in the need for research to reduce or eliminate emissions of these gases. Carbonation of magnesium and calcium silicate minerals is one possible method to achieve this reduction. It is possible to carry out these reactions either in situ (storage underground and subsequent reaction with the host rock to trap CO2 as carbonate minerals) or ex situ (above ground in a more traditional chemical processing plant). Research at the Department of Energy’s Albany Research Center has explored both of these routes. This paper will explore parameters that affect the direct carbonation of magnesium silicate minerals serpentine (Mg3Si2O5(OH)4) and olivine (Mg2SiO4) to produce magnesite (MgCO3), as well as the calcium silicate mineral, wollastonite (CaSiO3), to form calcite (CaCO3). The Columbia River Basalt Group is a multi-layered basaltic lava plateau that has favorable mineralogy and structure for storage of CO2. Up to 25% combined concentration of Ca, Fe2+, and Mg cations could react to form carbonates and thus sequester large quantities of CO2. Core samples from the Columbia River Basalt Group were reacted in an autoclave for up to 2000 hours at temperatures and pressures to simulate in situ conditions. Changes in core porosity, secondary minerals, and solution chemistry were measured.

Gerdemann, Stephen J.; Dahlin David C.; O'Connor William K.; Penner Larry R.

2003-11-01

117

Energy Prices, Taxes and Carbon Dioxide Emissions  

Microsoft Academic Search

Taxes levied on the carbon content of fuels (carbon taxes) are being considered in many OECD countries as a possible policy instrument to reduce carbon dioxide emissions. This paper first reviews the policy response in Member countries to the threat of global warming. It then discusses the link between carbon emission intensities and current energy prices, touching also on the

Peter Hoeller; Markku Wallin

1991-01-01

118

Mercury accumulation in grass and forb species as a function of atmospheric carbon dioxide concentrations and mercury exposures in air and soil.  

PubMed

The goal of this study was to investigate the potential for atmospheric Hg degrees uptake by grassland species as a function of different air and soil Hg exposures, and to specifically test how increasing atmospheric CO(2) concentrations may influence foliar Hg concentrations. Four common tallgrass prairie species were germinated and grown for 7 months in environmentally controlled chambers using two different atmospheric elemental mercury (Hg major; 3.7+/-2.0 and 10.2+/-3.5 ng m(-3)), soil Hg (<0.01 and 0.15+/-0.08 micro g g(-1)), and atmospheric carbon dioxide (CO(2)) (390+/-18, 598+/-22 micro mol mol(-1)) exposures. Species used included two C4 grasses and two C3 forbs. Elevated CO(2) concentrations led to lower foliar Hg concentrations in plants exposed to low (i.e., ambient) air Hg degrees concentrations, but no CO(2) effect was apparent at higher air Hg degrees exposure. The observed CO(2) effect suggests that leaf Hg uptake might be controlled by leaf physiological processes such as stomatal conductance which is typically reduced under elevated CO(2). Foliar tissue exposed to elevated air Hg degrees concentrations had higher concentrations than those exposed to low air Hg degrees , but only when also exposed to elevated CO(2). The relationships for foliar Hg concentrations at different atmospheric CO(2) and Hg degrees exposures indicate that these species may have a limited capacity for Hg storage; at ambient CO(2) concentrations all Hg absorption sites in leaves may have been saturated while at elevated CO(2) when stomatal conductance was reduced saturation may have been reached only at higher concentrations of atmospheric Hg degrees . Foliar Hg concentrations were not correlated to soil Hg exposures, except for one of the four species (Rudbeckia hirta). Higher soil Hg concentrations resulted in high root Hg concentrations and considerably increased the percentage of total plant Hg allocated to roots. The large shifts in Hg allocation patterns-notably under soil conditions only slightly above natural background levels-indicate a potentially strong role of plants in belowground Hg transformation and cycling processes. PMID:16631233

Millhollen, A G; Obrist, D; Gustin, M S

2006-10-01

119

Carbon dioxide capture process with regenerable sorbents  

DOEpatents

A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate. Spent sorbent containing the bicarbonate or carbonate is moved to a second reactor where it is heated or treated with a reducing agent such as, natural gas, methane, carbon monoxide hydrogen, or a synthesis gas comprising of a combination of carbon monoxide and hydrogen. The heat or reducing agent releases carbon dioxide gas and regenerates the active material for use as the sorbent material in the first reactor. New sorbent may be added to the regenerated sorbent prior to subsequent passes in the carbon dioxide removal reactor.

Pennline, Henry W. (Bethel Park, PA); Hoffman, James S. (Library, PA)

2002-05-14

120

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2013 CFR

...apparatus. The concentration of carbon dioxide in inspired gas in...section, the concentration of carbon dioxide in inspired gas at...inhalation portion of the breathing cycle shall not exceed the following...allowable average concentration of carbon dioxide in inspired air...

2013-10-01

121

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2014 CFR

...apparatus. The concentration of carbon dioxide in inspired gas in...section, the concentration of carbon dioxide in inspired gas at...inhalation portion of the breathing cycle shall not exceed the following...allowable average concentration of carbon dioxide in inspired air...

2014-10-01

122

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2010 CFR

...apparatus. The concentration of carbon dioxide in inspired gas in...section, the concentration of carbon dioxide in inspired gas at...inhalation portion of the breathing cycle shall not exceed the following...allowable average concentration of carbon dioxide in inspired air...

2010-10-01

123

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2012 CFR

...apparatus. The concentration of carbon dioxide in inspired gas in...section, the concentration of carbon dioxide in inspired gas at...inhalation portion of the breathing cycle shall not exceed the following...allowable average concentration of carbon dioxide in inspired air...

2012-10-01

124

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2011 CFR

...apparatus. The concentration of carbon dioxide in inspired gas in...section, the concentration of carbon dioxide in inspired gas at...inhalation portion of the breathing cycle shall not exceed the following...allowable average concentration of carbon dioxide in inspired air...

2011-10-01

125

Investigations of the spatial and temporal resolution of retrievals of atmospheric carbon dioxide from the Atmospheric InfraRed Sounder (AIRS)  

Microsoft Academic Search

As the dominant anthropogenic greenhouse gas, carbon dioxide (CO 2), represents an important component of climate change (IPCC 2007). Owing to burning of fossil fuels and deforestation, atmospheric CO2 concentrations have increased over 110 parts-per-million by volume (ppmv) from 270 ppmv to 380 ppmv since the dawn of the Industrial Revolution. Understanding of the spatial distribution of the sources and

Eric Sean Maddy

2007-01-01

126

The role of carbon dioxide in ammonia emission from manure  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ammonia emission from manure is a significant loss of fixed N from agricultural systems, and contributes to air pollution and ecosystem degradation. Despite the development of numerous mathematical models for predicting ammonia emission, the interactions between carbon dioxide emission, manure pH, a...

127

Air quality at Santiago, Chile: a box modeling approach—I. Carbon monoxide, nitrogen oxides and sulfur dioxide  

NASA Astrophysics Data System (ADS)

Ambient monitored data at Santiago, Chile, are analyzed using box models with the goal of assessing contributions of different economic activities to air pollution levels. The period analyzed is 1990-2000, characterized by the introduction of air pollution emissions standards, shift to unleaded gasoline and compressed natural gas, and steady growth of the private and public fleet and the associated fuel consumption growth. The box models explicitly include the seasonal behavior of meteorological variables; the results show that dispersion conditions in fall and winter seasons are 20-30% of the summertime values. This result explains the poor air quality in those seasons and shows that significant emissions reductions are required in order to improve air quality in wintertime. Emissions of CO, NO x and SO 2 are estimated from data on fuel consumption in the city; the estimated parameters are thus fleet-average or industry-average emission factors. In terms of contributions to ambient concentrations, older cars and diesel vehicles are the major contributors to CO and NO x impacts, with more than 60% and 50%, respectively. Ambient concentrations of SO 2 are largely dominated by stationary sources, although long range contributions are not negligible. By contrast, CO and NO x pollution is dominated by local sources within the city boundaries. The box models can be used for forecasting purposes, and they can predict annual average concentrations within 20% of the observed values. The methodology requires data on ambient air quality measurements and fuel consumption statistics, and produces quantitative results, which can be combined with economic models to analyze environmental regulation and public policies.

Jorquera, Héctor

128

New Trends In Carbon Dioxide Laser Microsurgery  

NASA Astrophysics Data System (ADS)

The carbon dioxide laser has been used for cutting and cauterizing tissue in a variety of surgical procedures by means of a dry-field air/tissue interface approach. Recently, a new wet-field CO2 laser technique has been developed and is being used successfully in humans to seal intraocular fibrovascular fronds and retinal tears at the time of vitrectomy, to close rubeotic vessels in the iris, and to excise fibrovascular fronds and epiretinal membranes in cases of severe diabetic retinopathy. Specialized wet-field CO2 photosurgical probes for use in gynecologic microsurgery have been developed and are being studied experimentally. Other potential applications include otolaryngologic micro-surgery, neurosurgery, and gastrointestinal and urologic wet-field surgery.

Smith, M. R.; Miller, James B.

1981-05-01

129

Photolytical Generation of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Carbon dioxide has been found by Cassini VIMS throughout the Saturnian system in locations such as Iapetus' equator where the temperature is too high for it to remain as free ice for more than a few hundred years. We suggest that the 4.26 micron absorption feature found on Iapetus and Hyperion (that has been attributed to complexed CO2) is the result of either UV photolysis or ion bombardment driving chemistry between the carbon rich layer and the water ice regolith. We conducted experiments to simulate the generation of CO2 by UV radiation under conditions similar to those on the surface of Iapetus. A simulated icy regolith was created in an argon atmosphere using flash-frozen, degassed water crushed into sub-millimeter sized particles. Isotopically labeled amorphous carbon (13C), which was ground into a fine dust, was mixed into the regolith allowing for extensive grain contact. This sample was placed in a vacuum chamber and cooled to temperatures as low at 60K. The sample was irradiated with UV light, and the products were measured using both a mass spectrometer to identify free molecules and an IR spectrometer for molecules that remained trapped on and in the simulated regolith. We report on the production and reaction rates of CO2 and CO, as well as the generation of free hydrogen and oxygen as detected by a SRS-100 mass spectrometer. We also identify residual products that either freeze on the surface or become entrained by or adsorbed onto the ice grains. We attempt to match the CO2 absorption feature found on Iapetus with that seen in our simulation, perhaps identifying a possible source of CO2 in the Saturnian system. Finally, we estimate the time required for these reactions to occur on Iapetus to see if UV photolysis would be effective.

Palmer, E. E.; Brown, R. H.

2008-12-01

130

Carbon dioxide conversion over carbon-based nanocatalysts.  

PubMed

The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity. PMID:23901504

Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

2013-07-01

131

Growth and yield response of field-grown tropical rice to increasing carbon dioxide and air temperature  

SciTech Connect

Although the response of rice (Oryza sativa L.) to increasing atmospheric CO{sub 2} concentration and air temperature has been examined at the greenhouse or growth chamber level, no field studies have been conducted under the tropical, irrigated conditions where the bulk of the world`s rice is grown. At the International Rice Research Institute, rice (cv. IR 72) was grown from germination until maturity for the 1994 wet and 1995 dry seasons at three different CO{sub 2} concentrations (ambient, ambient + 200, and ambient + 300 {mu}L L{sup {minus}1}) resulted in a significant increase in total plant biomass (+31%, +40%) and crop yield (+15%, + 27%) compared with the ambient control. The increase in crop yield was associated with an increase in the number of panicles per square meter and a greater percentage of filled spikelets. Simultaneous increases in CO{sub 2} and air temperature did not alter the biomass at maturity (relative to elevated CO{sub 2} alone), but plant development was accelerated at the higher growth temperature regardless of CO{sub 2} concentration. Grain yield, however, became insensitive to CO{sub 2} concentration at the higher growth temperature. Increasing both CO{sub 2} and air temperature also reduced grain quality (e.g., protein content). The combination of CO{sub 2} and temperature effects suggests that, in warmer regions (i.e., >34{degrees}C) where rice is grown, quantitative and qualitative changes in rice supply are possible if both CO{sub 2} and air temperature continue to increase. 24 refs., 6 figs., 4 tabs.

Ziska, L.H. [USDA-ARS, Beltsville, MD (United States); Namuco, O.; Moya, T.; Quilang, J. [International Rice Research Inst., Manila (Philippines)

1997-01-01

132

Extinguishment of methane diffusion flames by carbon dioxide in coflow air and oxygen-enriched microgravity environments  

Microsoft Academic Search

Microgravity experiments and computations have been conducted to elucidate stabilization and extinguishment mechanisms of methane diffusion flames, in the cup-burner configuration, with CO2 added gradually to a coflowing air or oxygen-enriched stream. The minimum extinguishing concentration of CO2 under low oxidizer velocities (<20 cm\\/s) was measured in microgravity achieved by parabolic flights of the NASA Reduced Gravity Aircraft. Transient computations

Fumiaki Takahashi; Gregory T. Linteris; Viswanath R. Katta

2008-01-01

133

LIFETIME OF EXCESS ATMOSPHERIC CARBON DIOXIDE  

EPA Science Inventory

We explore the effects of a changing terrestrial biosphere on the atmospheric residende time of carbon dioxide using three simple ocean carbon cycling models and a model of global terrestrial carbon cycling. e find differences in model behavior associated with the assumption of a...

134

40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.  

Code of Federal Regulations, 2013 CFR

40 ? Protection of Environment ? 19 ? 2013-07-01 ? 2013-07-01 ? false ? Carbon monoxide and carbon dioxide analyzer specifications. ? 86.316-79 ? Section 86.316-79 ? Protection of Environment ? ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ? AIR PROGRAMS (CONTINUED) ? CONTROL OF EMISSIONS FROM...

2013-07-01

135

Carbon Dioxide Emission Factors for Coal  

EIA Publications

The Energy Information Administration (EIA) has developed factors for estimating the amount of carbon dioxide emitted, accounting for differences among coals, to reflect the changing "mix" of coal in U.S. coal consumption.

1994-01-01

136

Carbon Dioxide Fluxes in European Russia  

NASA Astrophysics Data System (ADS)

Measurements of carbon balance of boreal ecosystems in the southern taiga of European Russia have been conducted using eddy covariance technique starting from 1998 to the present. The method allows to continuously collect net ecosystem exchange (NEE) fluxes of water and heat between forest and atmosphere with high time resolution. Simultaneous measurements of atmospheric meteorological parameters are carried out. The studies have been conducted in the Tver Region, Russia (Central Forest Biosphere Nature Reserve, 56N, 33E) using a 29 m high tower in low-productive wet spruce forest (P. Sphagnum forest, WSF), a 44 m high tower in high- productive complex spruce forest (CSF) and under the surface of ombrotrophic bog. Eddy flux measurements during limited time intervals are supplemented by measurements of soil, leaves and trunks respiration. Observations of decomposition speed of organic material and the rating NPP are conducted as well. In general, the measurements period has captured a wide range of changes of climatic conditions. Years with extreme dry and damp vegetative seasons and years with close to average climatic conditions for this region fall into the period of observations. The results of our measurements show that unmanaged uneven-aged spruce forests can be both source and sink of carbon to the atmosphere depending on the type of forest and weather conditions. Soil respiration as a result of decomposition of the abundant dead surface- and underground biomass determines the sign and absolute mean of the carbon balance. The overall annual balance of carbon of the studied forest ecosystems differs from zero. The cumulative total of the NEE fluxes for the period of April to October depends first of all on spring temperature and precipitation with temperature being within the range of 5-10C and on the duration of this period. For the period of active vegetation, when air temperature is higher than 10C - the NEE flux depends on humidity. We found significant seasonal and interannual variability of carbon dioxide fluxes for the ombrotrophic bog. The sign and the mean of carbon dioxide fluxes between the surface of the bog and the atmosphere depend on humidity conditions during the green season. When the water balance is negative the ombotrophic bog becomes a source of carbon for the atmosphere.

Kurbatova, J.; Varlagin, A.; Vygodskaya, N.

2007-12-01

137

Coupling of nitrate, carbon and heat in warm waters of the western equatorial Pacific: Consequences for estimating new production and air-sea exchange of carbon dioxide  

NASA Astrophysics Data System (ADS)

Recent studies indicate that the western equatorial Pacific Warm Pool may play an important role in interannual and decadal climate variation, global new production, and global atmosphere CO2 concentration. In this study, I compared the rates of new production and air-sea exchange of CO 2 in the western equatorial Pacific Warm Pool during normal conditions (December 1995/January 1996 and January 1997), during a moderate El Niño event (November/December 1994), and during the strongest El Niño event (December 1997/January 1998) in recent history. As an aid for interpreting and understanding of these processes I used both direct measurements and a box model. Direct measurements of the rate of nitrate uptake (new production) along the equator (from 145°E to 165°W) show that interannual variations in new production in the western and central equatorial Pacific correlate well with the change of the nutricline depth during the eastward expansion of the Warm Pool depending strongly upon the severity of the El Niño event. The analysis of nitrate, carbon, and heat balances in the western equatorial Pacific indicates that-in non-El Niño conditions-vertical turbulent diffusion is primarily responsible for both the loss of heat and the supply of nitrate and inorganic carbon to the euphotic zone. Based on this conclusion on the importance of vertical processes, I developed a box model that allows estimation of the rates of new production and air-sea CO2 exchange in the Warm Pool from the net surface heat flux, elemental ratios, and the C:N ratio of the organic matter sinking from the euphotic zone. The model predictions agree qualitatively with the direct measurements. The model may provide a means for estimating the rates of new production and air-sea CO2 exchange over the large areas of equatorial Pacific using the remotely- sensed data. The results of this study may also be useful in further understanding of the role of the western equatorial Pacific in biogeochemical cycles and climate variations, and for assessment of this part of the ocean for future fisheries demands.

Turk, Daniela

138

Bench-to-bedside review: Carbon dioxide  

Microsoft Academic Search

Carbon dioxide is a waste product of aerobic cellular respiration in all aerobic life forms. PaCO2 represents the balance between the carbon dioxide produced and that eliminated. Hypocapnia remains a common - and generally\\u000a underappreciated - component of many disease states, including early asthma, high-altitude pulmonary edema, and acute lung\\u000a injury. Induction of hypocapnia remains a common, if controversial, practice

Gerard Curley; John G Laffey; Brian P Kavanagh

2010-01-01

139

Atmospheric carbon dioxide record from flask measurements at Lampedusa Island  

NSDL National Science Digital Library

Air samples from Lampedusa Island, located south of Sicily in the Mediterranean sea, were collected weekly from May 1992 through December 2000 and analyzed for carbon dioxide content. "On the basis of annual averages calculated from monthly averages, CO2 levels at Lampedusa Island have risen from 360.80 in 1993 to 371.27 in 2000. The data show an average trend of +1.5 ppmv/y." The data from the study, newly available this month from the Carbon Dioxide Information Analysis Center (CDIAC), include a plot of mean carbon dioxide concentration (ppmv) against time and a text table of the annual mean values. Methods, notes, and references are also provided.

Chamard, Paolo.; Ciattaglia, Luigi.; Di Sarra, Alcide.; Monteleone, Francesco.

2001-01-01

140

A carbon dioxide air-gap microelectrode based on a neutral hydrogen ion exchanger pH microelectrode.  

PubMed

A relatively simple potentiometric pCO2 gas-sensing microelectrode is described. It is based on an ion-exchanger pH electrode, has a 2- to 5-microns tip, and has an air gap which is formed by means of hydrophobic treatments. The microelectrode exhibits a linear response in the range 10(-4)-10(-2) M with a Nernstian slope of 59 to 62 mV/decade at 25 degrees C. Ninety-five percent of the steady-state response time is about 20-30 s at the flow system when the concentration of sodium bicarbonate in buffer solution (pH 4.5) suddenly shifts from 0.2 to 2 mM and the lifetime is longer than 1 week. PMID:2113365

Ma, Y L

1990-04-01

141

A correlation of optimal heat rejection pressures in transcritical carbon dioxide cycles  

Microsoft Academic Search

In this work, a cycle simulation model has been developed to optimize the coefficient of performance (COP) of transcritical carbon dioxide air-conditioning cycles. The analysis shows that the COP of the transcritical carbon dioxide cycle varies nonmonotonically with the heat rejection pressure; a maximum COP occurs at an optimal heat rejection pressure. It is further revealed that the values of

S. M. Liao; T. S. Zhao; A. Jakobsen

2000-01-01

142

Mineralization strategies for carbon dioxide sequestration  

SciTech Connect

Progress is reported in three primary research areas--each concerned with sequestering carbon dioxide into mineral matrices. Direct mineral carbonation was pioneered at Albany Research Center. The method treats the reactant, olivine or serpentine in aqueous media with carbon dioxide at high temperature and pressure to form stable mineral carbonates. Recent results are introduced for pretreatment by high-intensity grinding to improve carbonation efficiency. To prove feasibility of the carbonation process, a new reactor was designed and operated to progress from batch tests to continuous operation. The new reactor is a prototype high-temperature, high-pressure flow loop reactor that will furnish information on flow, energy consumption, and wear and corrosion resulting from slurry flow and the carbonation reaction. A promising alternative mineralization approach is also described. New data are presented for long-term exposure of carbon dioxide to Colombia River Basalt to determine the extent of conversion of carbon dioxide to permanent mineral carbonates. Batch autoclave tests were conducted using drill-core samples of basalt and reacted under conditions that simulate in situ injection into basalt-containing geological formations.

Penner, Larry R.; O'Connor, William K.; Gerdemann, Stephen J.; Dahlin, David C.

2003-01-01

143

Carbon dioxide concentrations in the environment of sleeping infants.  

PubMed

In 22 infants continuous measurements were made of the concentration of carbon dioxide (CO2) in inspired air during sleep. Evidence was found of CO2 enrichment of inspired air in certain environmental conditions. The levels achieved were not sufficiently high to acutely endanger an infant. Carbon dioxide concentrations as high as 2-3% were observed in the prone position when the infant's head was under a blanket and when the lower face was obscured by bedding. Sleeping prone on a sheepskin also resulted in an increased concentration of CO2 but to a lesser extent than being under a blanket. In awake infants the presence of a pacifier also promoted an excess of CO2 in the inspired air, both in the prone and supine positions. The physiological and clinical implications of these findings, in relation to the Sudden Infant Death Syndrome (SIDS), are unknown and warrant investigation. PMID:8148189

Malcolm, G; Cohen, G; Henderson-Smart, D

1994-02-01

144

A Centrifuge-Based Technique for Dry Extraction of Air for Ice Core Studies of Carbon Dioxide.  

NASA Astrophysics Data System (ADS)

High resolution CO2 data from the Law Dome ice core document an abrupt ~10 ppm drop in CO2 at about 1600 AD (MacFarling Meure et al., Geophys. Res Lett., v. 33, L14810), which has been attributed to changes in human activities. CO2 measurements in ice cores are difficult, however, making verification of this feature an important task. We are undertaking a high-resolution study of CO2 between 1400 and 1800 AD in the WAIS Divide (Antarctica) ice core with a new dry extraction technique. The need for a dry extraction technique as opposed to a melt-refreeze technique in studies of CO2 from ice cores arises because of the well-documented artifacts in CO2 imposed by the presence of liquid water. Three dry-extraction methods have been employed by previous workers to measure CO2: needle-crushing method, ball-bearings method, and cheese-grater method (B. Stauffer, in: Encyclopedia of Quaternary Science, p. 1181, Elsevier 2007). Each has limitations, and we propose a simpler dry extraction technique, based on a large-capacity refrigerated centrifuge (the "centrifuge technique"), which eliminates the need to employ cryogenic temperatures to collect extracted gas and is more compatible with high sample throughput. The technique is now being tested on ~25-gram WAIS Divide samples in conjunction with CO2 measurements with a gas chromatograph. The technique employs a Beckman J- 6B centrifuge, in which evacuated stainless steel flask is placed: the flask has a weight inside positioned directly over a tall-standing piece of ice whose cross-section is small compared to that of the flask. Upon acceleration to 3000 rpm the weight moves down and presses the ice sample into a thin tablet covering flask's bottom, yielding the air extraction efficiency of ~80%. Preliminary tests suggest that precision and accuracy can be achieved at the level of ~1 ppm once the system is fine-tuned.

Grachev, A. M.; Brook, E. J.

2008-12-01

145

Atmospheric Lifetime of Fossil Fuel Carbon Dioxide  

E-print Network

Atmospheric Lifetime of Fossil Fuel Carbon Dioxide David Archer,1 Michael Eby,2 Victor Brovkin,3 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere literature on the atmospheric lifetime of fossil fuel CO2 and its impact on climate, and we present initial

Scherer, Norbert F.

146

Comparison of Global Model Results from the Carbon-Land Model Intercomparison Project (C-LAMP) with Free-Air Carbon Dioxide Enrichment (FACE) Manipulation Experiments  

SciTech Connect

Free-Air CO{sub 2} Enrichment (FACE) manipulation experiments have been carried out at a handful of sites to gauge the response of the biosphere to significant increases in atmospheric [CO{sub 2}]. Early synthesis results from four temperate forest sites suggest that the response of net primary productivity (NPP) is conserved across a broad range of productivity with a stimulation at the median of 23 {+-} 2% when the surrounding air [CO{sub 2}] was raised to 550{approx}ppm. As a part of the Carbon-Land Model Intercomparison Project (C-LAMP), a community-based model-data comparison activity, the authors have performed a global FACE modeling experiment using two terrestrial biogeochemistry modules, CLM3-CASA and CLM3-CN, coupled to the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM). The two models were forced with an improved NCEP/NCAR reanalysis data set and reconstructed atmospheric [CO{sub 2}] and N deposition data through 1997. At the beginning of 1997 in the transient simulations, global atmospheric [CO{sub 2}] was abruptly raised to 550{approx}ppm, the target value used at the FACE sites. In the control runs, [CO{sub 2}] continued to rise following observations until 2004, after which it was held constant out to year 2100. In both simulations, the last 25 years of reanalysis forcing and a constant N deposition were applied after year 2004. Across all forest biomes, the NPP responses from both models are weaker than those reported for the four FACE sites. Moreover, model responses vary widely geographically with a decreasing trend of NPP increases from 40{sup o}N to 70{sup o}N. For CLM3-CASA, the largest responses occur in arid regions of western North America and central Asia, suggesting that responses are most strongly influenced by increased water use efficiency for this model. CLM3-CN exhibits consistently weaker responses than CLM3-CASA' with the strongest responses in central Asia, but significantly constrained by N limitation. C-LAMP is a sub-project of the Computational Climate Science End Station led by Dr. Warren Washington, using computing resources at the U.S. Department of Energy's National Center for Computational Sciences (NCCS).

Hoffman, Forrest M [ORNL; Randerson, Jim [University of California, Irvine; Fung, Inez [University of California, Berkeley; Thornton, Peter E [ORNL; Covey, Curtis [Lawrence Livermore National Laboratory (LLNL); Bonan, Gordon [National Center for Atmospheric Research (NCAR); Running, Steven [University of Montana, Missoula; Norby, Richard J [ORNL

2008-01-01

147

Where in the World is Carbon Dioxide?  

NSDL National Science Digital Library

This three part activity has students set up experiments to help them better understand the atmospheric portion of the carbon cycle. From this activity, they will be able to explain the concept of sources and sinks as they relate to carbon dioxide, the use of indicator solution bromothymol blue (BTB) to reveal the presence of carbon dioxide, and the qualitative differences between animal and fossil fuel sources of global carbon dioxide. The student guide has an overall description of all three parts of the activity, lists of materials, the procedure and observations and questions. The instructor guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.

148

Electrocatalytic Reduction of Carbon Dioxide to Methane  

NASA Technical Reports Server (NTRS)

A room-temperature electrocatalytic process that effects the overall chemical reaction CO2 + 2H2O yields CH4 + 2O2 has been investigated as a means of removing carbon dioxide from air and restoring oxygen to the air. The process was originally intended for use in a spacecraft life-support system, in which the methane would be vented to outer space. The process may also have potential utility in terrestrial applications in which either or both of the methane and oxygen produced might be utilized or vented to the atmosphere. A typical cell used to implement the process includes a polymer solid-electrolyte membrane, onto which are deposited cathode and anode films. The cathode film is catalytic for electrolytic reduction of CO2 at low overpotential. The anode film is typically made of platinum. When CO2 is circulated past the cathode, water is circulated past the anode, and a suitable potential is applied, the anode half-cell reaction is 4H2O yields 2O2 + 8H(+) + 8e(-). The H(+) ions travel through the membrane to the cathode, where they participate in the half-cell reaction CO2 + 8H(+) + 8e(-) yields CH4 + 2H2O.

Sammells, Anthony F.; Spiegel, Ella F.

2008-01-01

149

Method for Extracting and Sequestering Carbon Dioxide  

SciTech Connect

A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO2 from a gaseous environment.

Rau, Gregory H.; Caldeira, Kenneth G.

2005-05-10

150

Apparatus for extracting and sequestering carbon dioxide  

DOEpatents

An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Rau, Gregory H. (Castro Valley, CA); Caldeira, Kenneth G. (Livermore, CA)

2010-02-02

151

Method for extracting and sequestering carbon dioxide  

DOEpatents

A method and apparatus to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said method and apparatus hydrates CO.sub.2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Rau, Gregory H. (Castro Valley, CA); Caldeira, Kenneth G. (Livermore, CA)

2005-05-10

152

Designed amyloid fibers as materials for selective carbon dioxide capture  

PubMed Central

New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via carbamate formation. Thermodynamic and kinetic capture-and-release tests show the carbamate formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 °C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture. PMID:24367077

Li, Dan; Furukawa, Hiroyasu; Deng, Hexiang; Liu, Cong; Yaghi, Omar M.; Eisenberg, David S.

2014-01-01

153

SEQUESTERING CARBON DIOXIDE IN COALBEDS  

SciTech Connect

The authors' long-term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure, and adsorbent types. The originally-stated, major objectives of the current project are to: (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen, and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coals being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane, and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. As this project developed, an important additional objective was added to the above original list. Namely, we were encouraged to interact with industry and/or governmental agencies to utilize our expertise to advance the state of the art in coalbed adsorption science and technology. As a result of this additional objective, we participated with the Department of Energy and industry in the measurement and analysis of adsorption behavior as part of two distinct investigations. These include (a) Advanced Resources International (ARI) DOE Project DE-FC26-00NT40924, ''Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on Wet Tiffany Coal'', and (b) the DOE-NETL Project, ''Round Robin: CO{sub 2} Adsorption on Selected Coals''. These activities, contributing directly to the DOE projects listed above, also provided direct synergism with the original goals of our work. Specific accomplishments of this project are summarized below in three broad categories: experimentation, model development, and coal characterization.

K.A.M. Gasem; R.L. Robinson, Jr.; J.E. Fitzgerald; Z. Pan; M. Sudibandriyo

2003-04-30

154

SEQUESTERING CARBON DIOXIDE IN COALBEDS  

SciTech Connect

The authors' long-term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure and adsorbent types. The originally-stated, major objectives of the current project are to (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen, and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coals being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. As this project has developed, an important additional objective has been added to the above original list. Namely, we have been encouraged to interact with industry and/or governmental agencies to utilize our expertise to advance the state of the art in coalbed adsorption science and technology. As a result of this additional objective, we have participated with the Department of Energy and industry in the measurement and analysis of adsorption behavior as part of two distinct investigations. These include (a) Advanced Resources International (ARI) DOE Project DE-FC26-00NT40924, ''Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on Wet Tiffany Coal'', and (b) the DOE-NETL Project, ''Round Robin: CO{sub 2} Adsorption on Selected Coals''. These activities, contributing directly to the DOE projects listed above, have also provided direct synergism with the original goals of our work. Specific accomplishments of this project during the current reporting period are summarized in three broad categories outlining experimentation, model development, and coal characterization.

K.A.M. Gasem; R.L. Robinson, Jr.; L.R. Radovic

2003-03-10

155

Global deforestation: contribution to atmospheric carbon dioxide  

Microsoft Academic Search

A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1960 and 1980 was between 135 X 10¹⁵ and 228 X 10¹⁵ grams. Between 1.8 X 10¹⁵ and 4.7 X 10¹⁵ grams of carbon were released in 1980, of which nearly

G. M. Woodwell; J. E. Hobbie; R. A. Houghton; J. M. Melillo; B. Moore; B. J. Peterson; G. R. Shaver

1983-01-01

156

Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.  

PubMed

Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P < or = 0.10) for sap flux- and (for birch) 13C-derived leaf conductance. Canopy conductance was significantly increased by elevated CO2 but not significantly affected by elevated O3. Investigation of a short-term gap in CO2 enrichment demonstrated a +10% effect of transient exposure of elevated CO2-grown trees to ambient CO2 on g(c). All treatment effects were similar in pure aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in pure aspen and mixed aspen-birch forests. Our results, together with the findings from other long-term FACE experiments with trees, suggest that model assumptions of large reductions in stomatal conductance under rising atmospheric CO2 are very uncertain for forests. PMID:19773339

Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

2009-11-01

157

Polymers for metal extractions in carbon dioxide  

DOEpatents

A composition useful for the extraction of metals and metalloids comprises (a) carbon dioxide fluid (preferably liquid or supercritical carbon dioxide); and (b) a polymer in the carbon dioxide, the polymer having bound thereto a ligand that binds the metal or metalloid; with the ligand bound to the polymer at a plurality of locations along the chain length thereof (i.e., a plurality of ligands are bound at a plurality of locations along the chain length of the polymer). The polymer is preferably a copolymer, and the polymer is preferably a fluoropolymer such as a fluoroacrylate polymer. The extraction method comprises the steps of contacting a first composition containing a metal or metalloid to be extracted with a second composition, the second composition being as described above; and then extracting the metal or metalloid from the first composition into the second composition.

DeSimone, Joseph M. (7315 Crescent Ridge Dr., Chapel Hill, NC 27516); Tumas, William (1130 Big Rock Loop, Los Alamos, NM 87544); Powell, Kimberly R. (103 Timber Hollow Ct. Apartment 323, Chapel Hill, NC 27514); McCleskey, T. Mark (1930 Camino Mora, Los Alamos, NM 87544); Romack, Timothy J. (5810 Forest Ridge Dr., Durham, NC 27713); McClain, James B. (8530 Sommersweet La., Raleigh, NC 27612); Birnbaum, Eva R. (1930 Camino Mora, Los Alamos, NM 87544)

2001-01-01

158

Do Plants Really Use Carbon Dioxide?  

NSDL National Science Digital Library

This experiment demonstrates that plants use carbon dioxide during photosynthesis. Four Teaching Tanks (commercially available, narrow tanks) are filled with water and bromthymol blue indicator, and Elodea plants are added to two of the tanks. Blowing through a straw into each tank dissolves carbon dioxide into the water and turns the indicator yellow. The tanks are sealed with clay, and a pair of tanks—one tank with Elodea and one without—is put in sunlight, while the other pair is put in darkness. After an hour, the tank with Elodea in sunlight will have returned to blue color. Learners can infer that the carbon dioxide in that tank has been used by the Elodea, since the water in "control" tanks remains yellow. Though designed as a demonstration, this activity could be adapted to allow varying degrees of learner hands-on involvement, and higher grade learners could potentially do all the steps without a demonstrator.

American Educational Products

1992-01-01

159

Regenerable immobilized aminosilane sorbents for carbon dioxide capture applications  

SciTech Connect

A method for the separation of carbon dioxide from ambient air and flue gases is provided wherein a phase separating moiety with a second moiety are simultaneously coupled and bonded onto an inert substrate to create a mixture which is subsequently contacted with flue gases or ambient air. The phase-separating moiety is an amine whereas the second moiety is an aminosilane, or a Group 4 propoxide such as titanium (IV) propoxide (tetrapropyl orthotitanate, C.sub.12H.sub.28O.sub.4Ti). The second moiety makes the phase-separating moiety insoluble in the pores of the inert substrate. The new sorbents have a high carbon dioxide loading capacity and considerable stability over hundreds of cycles. The synthesis method is readily scalable for commercial and industrial production.

Gay, McMahan; Choi, Sunho; Jones, Christopher W

2014-09-16

160

Global deforestation: contribution to atmospheric carbon dioxide  

SciTech Connect

A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1960 and 1980 was between 135 X 10/sup 15/ and 228 X 10/sup 15/ grams. Between 1.8 X 10/sup 15/ and 4.7 X 10/sup 15/ grams of carbon were released in 1980, of which nearly 80 percent was due to deforestation, principally in the tropics. The annual release of carbon from the biota and soils exceeded the release from fossil fuels until about 1960. Because the biotic release has been and remains much larger than is commonly assumed, the airborne fraction, usually considered to be about 50 percent of the releases from fossil fuels, was probably between 22 and 43 percent of the total carbon released in 1980. The increase in carbon dioxide in the atmosphere is thought by some to be increasing the storage of carbon in the earth's remaining forests sufficiently to offset the release from deforestation. The interpretation of the evidence presented here suggests no such effect; deforestation appears to be the dominant biotic effect on atmospheric carbon dioxide. If deforestation increases in proportion to population, the biotic release of carbon will reach 9 X 10/sup 15/ grams per year before forests are exhausted early in the next century. The possibilities for limiting the accumulation of carbon dioxide in the atmosphere through reduction in use of fossil fuels and through management of forests may be greater than is commonly assumed.

Woodwell, G.M.; Hobbie, J.E.; Houghton, R.A.; Melillo, J.M.; Moore, B.; Peterson, B.J.; Shaver, G.R.

1983-12-09

161

International Space Station Carbon Dioxide Removal Assembly Testing  

NASA Technical Reports Server (NTRS)

Performance testing of the International Space Station Carbon Dioxide Removal Assembly flight hardware in the United States Laboratory during 1999 is described. The CDRA exceeded carbon dioxide performance specifications and operated flawlessly. Data from this test is presented.

Knox, James C.

2000-01-01

162

Organic syntheses employing supercritical carbon dioxide as a reaction solvent  

NASA Technical Reports Server (NTRS)

Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

1991-01-01

163

Carbon dioxide dynamics in an artificial ecosystem  

NASA Astrophysics Data System (ADS)

An experimental artificial ecosystem was established as a tool to understand the behavior of closed ecosystem and to develop the technology for a future bioregenerative life support system for lunar or planetary exploration. Total effective volume of the system is 0.7 m3 . It consists of a higher plant chamber, an animal chamber and a photo-bioreactor which cultivated lettuce (Lactuca sativa L.), silkworm (Bombyx Mori L.) and microalgae (Chlorella), respectively. For uniform and sustained observations, lettuce and silkworms was cultivated using sequential cultivation method, and microalgae using continuous culture. Four researchers took turns breathing the system air through a tube for brief periods every few hours. A mathematic model, simulating the carbon dioxide dynamics was developed. The main biological parameters concerning photosynthesis of lettuce and microalgae, respiration of silkworms and human were validated by the experimental data. The model described the respiratory relationship between autotrophic and heterotrophic compartments. A control strategy was proposed as a tool for the atmosphere management of the artificial ecosystem.

Hu, Enzhu; Hu, Dawei; Tong, Ling; Li, Ming; Fu, Yuming; He, Wenting; Liu, Hong

164

Euthanasia of neonatal mice with carbon dioxide  

USGS Publications Warehouse

Exposure to carbon dioxide (CO2) is the most prevalent method used to euthanize rodents in biomedical research. The purpose of this study was to determine the time of CO2 exposure required to euthanize neonatal mice (0 to 10 days old). Multiple groups of mice were exposed to 100% CO 2 for time periods between 5 and 60 min. Mice were placed in room air for 10 or 20 min after CO2 exposure, to allow for the chance of recovery. If mice recovered at one time point, a longer exposure was examined. Inbred and outbred mice were compared. Results of the study indicated that time to death varied with the age of the animals and could be as long as 50 min on the day of birth and differed between inbred and outbred mice. Institutions euthanizing neonatal mice with CO2 may wish to adjust their CO 2 exposure time periods according the age of the mice and their genetic background. Copyright 2005 by the American Association for Laboratory Animal Science.

Pritchett, K.; Corrow, D.; Stockwell, J.; Smith, A.

2005-01-01

165

Effects of carbon dioxide on laryngeal receptors  

SciTech Connect

Carbon dioxide (CO{sub 2}) either stimulates or inhibits laryngeal receptors in the cat. The aim of this study was to correlate the CO{sub 2} response of laryngeal receptors with their response to other known stimuli (i.e. pressure, movement, cold, water and smoke). Single unit action potentials were recorded from fibers in the superior laryngeal nerve of 5 anesthetized, spontaneously breathing dogs together with CO{sub 2} concentration, esophageal and subglottic pressure. Constant streams of warm, humidified air or 10% CO{sub 2} in O{sub 2} were passed through the functionally isolated upper airway for 60 s. Eight of 13 randomly firing or silent receptors were stimulated by CO{sub 2} (from 0.4{plus minus}0.1 to 1.8{plus minus}0.4 imp.s). These non-respiratory-modulated receptors were more strongly stimulated by solutions lacking Cl{sup {minus}} and/or cigarette smoke. Six of 21 respiratory modulated receptors (responding to pressure and/or laryngeal motion) were either inhibited or stimulated by CO{sub 2}. Our results show that no laryngeal receptor responds only to CO{sub 2}. Silent or randomly active receptors were stimulated most often by CO{sub 2} consistent with the reflex effect of CO{sub 2} in the larynx.

Anderson, J.W.; Sant'Ambrogio, F.B.; Orani, G.P.; Sant'Ambrogio, G.; Mathew, O.P. (Univ. of Texas, Galveston (United States))

1990-02-26

166

U.S. Energy-Related Carbon Dioxide Emissions  

EIA Publications

U.S. Energy Information Administration releases its online analysis of 2012 energy-related carbon dioxide emissions today. It indicates U.S. carbon dioxide emissions from the consumption of fossil fuels were 5,290 million metric tons carbon dioxide in 2012, a decrease of almost 4% from the 2011 level. Energy-related carbon dioxide emissions have declined in five of the last seven years and are the lowest they have been since 1994.

2014-01-01

167

Discussion of Refrigeration Cycle Using Carbon Dioxide as Refrigerant  

NASA Astrophysics Data System (ADS)

Nowadays, the problem of the environment goes worse, it urges people to research and study new energy-saving and environment-friendly refrigerants, such as carbon dioxide, at present, people do research on carbon dioxide at home and abroad. This paper introduces the property of carbon dioxide as a refrigerant, sums up and analyses carbon dioxide refrigeration cycles, and points out the development and research direction in the future.

Ji, Amin; Sun, Miming; Li, Jie; Yin, Gang; Cheng, Keyong; Zhen, Bing; Sun, Ying

168

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Carbon dioxide analyzer calibration...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...Procedures § 86.124-78 Carbon dioxide analyzer calibration...monthly thereafter the NDIR carbon dioxide analyzer shall be...

2013-07-01

169

40 CFR 86.1324-84 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Carbon dioxide analyzer calibration...Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines...Procedures § 86.1324-84 Carbon dioxide analyzer calibration...monthly thereafter, the NDIR carbon dioxide analyzer shall be...

2010-07-01

170

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Carbon dioxide analyzer calibration...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...Procedures § 86.124-78 Carbon dioxide analyzer calibration...monthly thereafter the NDIR carbon dioxide analyzer shall be...

2010-07-01

171

40 CFR 86.1324-84 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Carbon dioxide analyzer calibration...Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines...Procedures § 86.1324-84 Carbon dioxide analyzer calibration...monthly thereafter, the NDIR carbon dioxide analyzer shall be...

2013-07-01

172

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Carbon dioxide analyzer calibration...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...Procedures § 86.124-78 Carbon dioxide analyzer calibration...monthly thereafter the NDIR carbon dioxide analyzer shall be...

2012-07-01

173

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Carbon dioxide analyzer calibration...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...Procedures § 86.124-78 Carbon dioxide analyzer calibration...monthly thereafter the NDIR carbon dioxide analyzer shall be...

2014-07-01

174

40 CFR 86.1324-84 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Carbon dioxide analyzer calibration...Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines...Procedures § 86.1324-84 Carbon dioxide analyzer calibration...monthly thereafter, the NDIR carbon dioxide analyzer shall be...

2011-07-01

175

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Carbon dioxide analyzer calibration...Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles...Procedures § 86.124-78 Carbon dioxide analyzer calibration...monthly thereafter the NDIR carbon dioxide analyzer shall be...

2011-07-01

176

40 CFR 86.1324-84 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Carbon dioxide analyzer calibration...Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines...Procedures § 86.1324-84 Carbon dioxide analyzer calibration...monthly thereafter, the NDIR carbon dioxide analyzer shall be...

2012-07-01

177

Chukwuemeka I. Okoye Carbon Dioxide Solubility and Absorption Rate in  

E-print Network

Copyright by Chukwuemeka I. Okoye 2005 #12;Carbon Dioxide Solubility and Absorption Rate _______________________ Nicholas A. Peppas #12;Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O for. #12;iii Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O

Rochelle, Gary T.

178

Designed amyloid fibers as materials for selective carbon dioxide capture  

E-print Network

Designed amyloid fibers as materials for selective carbon dioxide capture Dan Lia,b,c,1 , Hiroyasu demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide

179

A Simple Model for Atmospheric Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will create and use a differential equation of rate-of-change of atmospheric carbon dioxide. They will refer to the "Keeling Curve" graph and information on the sources and sinks of carbon on Earth to create the equation and apply it to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

2012-08-03

180

RISING CARBON DIOXIDE AND WEED ECOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Documented and projected changes in the concentration of atmospheric carbon dioxide [CO2] and other gases suggest potential changes in climate stability which could negatively impact human systems. One such system would involve negative impacts on agricultural crops and associated weeds. Climatic o...

181

Carbon dioxide enhances fragility of ice crystals  

NASA Astrophysics Data System (ADS)

Ice caps and glaciers cover 7% of the Earth, greater than the land area of Europe and North America combined, and play an important role in global climate. The small-scale failure mechanisms of ice fracture, however, remain largely elusive. In particular, little understanding exists about how the presence and concentration of carbon dioxide molecules, a significant component in the atmosphere, affects the propensity of ice to fracture. Here we use atomic simulations with the first-principles based ReaxFF force field capable of describing the details of chemical reactions at the tip of a crack, applied to investigate the effects of the presence of carbon dioxide molecules on ice fracture. Our result shows that increasing concentrations of carbon dioxide molecules significantly decrease the fracture toughness of the ice crystal, making it more fragile. Using enhanced molecular sampling with metadynamics we reconstruct the free energy landscape in varied chemical microenvironments and find that carbon dioxide molecules affect the bonds between water molecules at the crack tip and decrease their strength by altering the dissociation energy of hydrogen bonds. In the context of glacier dynamics our findings may provide a novel viewpoint that could aid in understanding the breakdown and melting of glaciers, suggesting that the chemical composition of the atmosphere can be critical to mediate the large-scale motion of large volumes of ice.

Qin, Zhao; Buehler, Markus J.

2012-11-01

182

21 CFR 582.1240 - Carbon dioxide.  

Code of Federal Regulations, 2010 CFR

21 ? Food and Drugs ? 6 ? 2010-04-01 ? 2010-04-01 ? false ? Carbon dioxide. ? 582.1240 ? Section 582.1240 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2010-04-01

183

21 CFR 582.1240 - Carbon dioxide.  

Code of Federal Regulations, 2012 CFR

21 ? Food and Drugs ? 6 ? 2012-04-01 ? 2012-04-01 ? false ? Carbon dioxide. ? 582.1240 ? Section 582.1240 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2012-04-01

184

21 CFR 582.1240 - Carbon dioxide.  

Code of Federal Regulations, 2011 CFR

21 ? Food and Drugs ? 6 ? 2011-04-01 ? 2011-04-01 ? false ? Carbon dioxide. ? 582.1240 ? Section 582.1240 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2011-04-01

185

21 CFR 582.1240 - Carbon dioxide.  

Code of Federal Regulations, 2014 CFR

21 ? Food and Drugs ? 6 ? 2014-04-01 ? 2014-04-01 ? false ? Carbon dioxide. ? 582.1240 ? Section 582.1240 ? Food and Drugs ? FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ? ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ? SUBSTANCES GENERALLY RECOGNIZED AS SAFE...

2014-04-01

186

Ocean Acidification: The Other Carbon Dioxide Problem  

NSDL National Science Digital Library

This NOAA video discusses how the ocean absorbs the increased amount of carbon dioxide released into the atmosphere, thereby changing the pH and buffering action of the ocean. These changes in pH are impacting calcifying organisms, such as corals and shellfish, and related food chains and ecosystems.

Noaa; Administration, National O.

187

Carbon Dioxide Corrosion: Modelling and Experimental Work  

E-print Network

Carbon Dioxide Corrosion: Modelling and Experimental Work Applied to Natural Gas Pipelines Philip in the corrosion related research institutions at IFE and the Ohio University or any other scientific research;#12;Introduction - v - Summary CO2 corrosion is a general problem in the industry and it is expensive. The focus

188

CDIAC: Carbon Dioxide Information Analysis Center  

NSDL National Science Digital Library

This site is the homepage of the Carbon Dioxide Information Analysis Center (CDIAC) which includes the World Data Center for Atmospheric Trace Gases. CDIAC is the primary global-change data and information analysis center of the U.S. Department of Energy (DOE). CDIAC responds to data and information requests from users from all over the world who are concerned with the greenhouse effect and global climate change. CDIAC's data holdings include records of the concentrations of carbon dioxide and other radiatively active gases in the atmosphere; the role of the terrestrial biosphere and the oceans in the biogeochemical cycles of greenhouse gases; emissions of carbon dioxide to the atmosphere; long-term climate trends; the effects of elevated carbon dioxide on vegetation; and the vulnerability of coastal areas to rising sea level. In operation since 1982, CDIAC: obtains, evaluates, and archives data, compiles and distributes digital numeric data packages and computer model packages, provides data management support to global-change related scientific projects, distributes related reports, produces the newsletter, CDIAC Communications, and in general acts as the information focus for the U.S. DOE Global Change Research Program. CDIAC is supported by DOE's Environmental Sciences Division of the Office of Biological and Environmental Research. CDIAC represents DOE in the multi-agency Global Change Data and Information System.

189

Atmospheric carbon dioxide record from Mauna Loa  

NSDL National Science Digital Library

The Scripps Institute of Oceanography has released these data consisting of monthly carbon dioxide concentrations at Mauna Loa 1958-1999. Measurements were made using a nondispersive infrared gas analyzer with a water vapor freeze trap. The data are available as graphs or tables. The text includes a brief overview of the methods and a reference list.

190

The Transport Properties of Carbon Dioxide  

Microsoft Academic Search

The paper contains new, representative equations for the viscosity and thermal conductivity of carbon dioxide. The equations are based in part upon a body of experimental data that have been critically assessed for internal consistency and for agreement with theory whenever possible. In the case of the low-density thermal conductivity at high temperatures, all available data are shown to be

V. Vesovic; W. A. Wakeham; G. A. Olchowy; J. V. Sengers; J. T. R. Watson; J. Millat

1990-01-01

191

Recent Events: a Perspective on Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will compare the carbon dioxide produced as a result of two 2010 events: the eruption of the Eyjafjalla Volcano and the burning of oil on the ocean surface to address the Gulf of Mexico oil spill. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

192

Inhalation of Carbon Dioxide at High Altitudes  

Microsoft Academic Search

THE suggestion put forward in NATURE of March 23 (p. 457) by Prof. Yandell Henderson and others to the effect that carbon dioxide might be of use in high altitude climbing reminds me of some trials carried out about ten years ago. Messrs. Siebe German and Co., Ltd., had similar ideas, and they lent me a rebreathing mask to try

P. J. H. Unna

1935-01-01

193

Carbon Dioxide Production at Home  

NSDL National Science Digital Library

In this problem set, learners will consider the "Carbon Footprint" of a family of four in a given context, as well as the US and global averages, and compare that with their own to answer a series of questions. They will use an online Carbon Footprint calculator to determine their own per-capita carbon production. Answer key is provided. This problem is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

2012-08-03

194

Dissolved inorganic carbon dynamics and air-sea carbon dioxide fluxes during coccolithophore blooms in the northwest European continental margin (northern Bay of Biscay)  

Microsoft Academic Search

We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the coccolithophore Emiliania huxleyi occurred, as indicated by patches of high reflectance on remote sensing images, phytoplankton pigment signatures, and microscopic examinations. Total alkalinity showed

Kim Suykens; Bruno Delille; Lei Chou; C. De Bodt; Jérôme Harlay; Alberto V. Borges

2010-01-01

195

Dynamic solubility measurements of caffeine in carbon dioxide and in carbon dioxide saturated with water  

NASA Astrophysics Data System (ADS)

The solubility of caffeine in dry carbon dioxide has been measured between 310 and 430 K up to 70 MPa. The solubility of caffeine in carbon dioxide saturated with water has been measured between 303 and 363 K up to 30 MPa. The results can be reproduced by simple equations. These equations allow a calculation of the solubilities at higher and lower pressures. Using these equations, cross virial coefficients have been calculated for both systems.

Lentz, Harro; Gehrig, Manfred; Schulmeyer, Josef

1986-05-01

196

In-cabin Exposure Levels of Carbon Monoxide, Carbon Dioxide and Airborne Particulate Matter in Air-Conditioned Buses of Hong Kong  

Microsoft Academic Search

Bus cabin air quality has not been incessantly monitored in Hong Kong. This study investigates the in-cabin exposure levels of CO, CO2 and PM10 for running buses in Hong Kong that are equipped with Euro II, III and IV engines. A representative urban—suburban bus route was chosen and there were no significantly different in-cabin CO levels reported among engine types

L. T. Wong; K. W. Mui; C. T. Cheung; W. Y. Chan; Y. H. Lee; C. L. Cheung

2011-01-01

197

Coral, Carbon Dioxide and Calcification  

NSDL National Science Digital Library

In this group activity, learners act out key stages of the "ocean carbon cycle" (also known as the "carbonate buffer system") through motions, rearranging blocks and team tasks. Learners will also hypothesize the potential effects on the ocean and coral when variables are changed (e.g. the addition of massive amounts of CO2 and increased water temperature). At least 8 learners are needed to participate in the simulation. This detailed lesson plan includes an introduction, background information related to corals and the ocean carbon cycle, and adaptation suggestions for younger learners.

Stephanie L. Anderson

2012-07-17

198

Personal Carbon Dioxide Impact (title provided or enhanced by cataloger)  

NSDL National Science Digital Library

The amount of carbon dioxide in the atmosphere has been increasing for many decades now, mostly due to the burning of fossil fuels by mankind. In this exercise, students will track their daily activities, and and estimate how much carbon dioxide they are responsible for emitting with the use of an online Personal Greenhouse Gas Calculator developed by the U.S. Environmental Protection Agency (EPA). The calculator sums the carbon dioxide produced by driving, electricity use, and waste disposal, and provides an estimate of annual carbon dioxide emissions. It also allows users to see how changes in lifestyle could reduce carbon dioxide emissions. Links to websites with additional information are also provided.

Pratte, John

199

High Levels of Carbon Dioxide Threaten Oyster Survival  

NSDL National Science Digital Library

It has been widely reported that the build up of carbon dioxide (CO2) in the air, which is caused by human behavior, will likely lead to climate change and have major implications for life on earth. But less focus has been given to global warmingÃÂs evil twin, ocean acidification, which occurs when CO2 lowers the pH of water bodies, thus making them more acidic. This lesser known phenomenon may have catastrophic effects on all sea life. Inna Sokolova, associate professor of biology at the University of North Carolina at Charlotte, studies the affect of high carbon dioxide on oyster survival, growth and shell hardness. The results of her research suggest that creatures once thought to be fairly adaptable to changes in the environment, may be in serious trouble.

APS Communications Office (American Physiological Society Communications Office)

2010-08-04

200

Modeling Carbon Dioxide, pH and Un-Ionized Ammonia Relationships in Serial Reuse Systems  

USGS Publications Warehouse

In serial reuse systems, excretion of metabolic carbon dioxide has a significant impact on ambient pH, carbon dioxide, and un-ionized ammonia concentrations. This impact depends strongly on alkalinity, water flow rate, feeding rate, and loss of carbon dioxide to the atmosphere. A reduction in pH from metabolic carbon dioxide can significantly reduce the un-ionized ammonia concentration and increase the carbon dioxide concentrations compared to those parameters computed from influent pH. The ability to accurately predict pH in serial reuse systems is critical to their design and effective operation. A trial and error solution to the alkalinity–pH system was used to estimate important water quality parameters in serial reuse systems. Transfer of oxygen and carbon dioxide across the air–water interface, at overflow weirs, and impacts of substrate-attached algae and suspended bacteria were modeled. Gas transfer at the weirs was much greater than transfer across the air–water boundary. This simulation model can rapidly estimate influent and effluent concentrations of dissolved oxygen, carbon dioxide, and un-ionized ammonia as a function of water temperature, elevation, water flow, and weir type. The accuracy of the estimates strongly depends on assumed pollutional loading rates and gas transfer at the weirs. The current simulation model is based on mean daily loading rates; the impacts of daily variation loading rates are discussed. Copies of the source code and executable program are available free of charge.

Watten, Barnaby J.; Rust, Michael; Colt, John

2009-01-01

201

Modeling carbon dioxide, pH, and un-ionized ammonia relationships in serial reuse systems  

USGS Publications Warehouse

In serial reuse systems, excretion of metabolic carbon dioxide has a significant impact on ambient pH, carbon dioxide, and un-ionized ammonia concentrations. This impact depends strongly on alkalinity, water flow rate, feeding rate, and loss of carbon dioxide to the atmosphere. A reduction in pH from metabolic carbon dioxide can significantly reduce the un-ionized ammonia concentration and increase the carbon dioxide concentrations compared to those parameters computed from influent pH. The ability to accurately predict pH in serial reuse systems is critical to their design and effective operation. A trial and error solution to the alkalinity-pH system was used to estimate important water quality parameters in serial reuse systems. Transfer of oxygen and carbon dioxide across the air-water interface, at overflow weirs, and impacts of substrate-attached algae and suspended bacteria were modeled. Gas transfer at the weirs was much greater than transfer across the air-water boundary. This simulation model can rapidly estimate influent and effluent concentrations of dissolved oxygen, carbon dioxide, and un-ionized ammonia as a function of water temperature, elevation, water flow, and weir type. The accuracy of the estimates strongly depends on assumed pollutional loading rates and gas transfer at the weirs. The current simulation model is based on mean daily loading rates; the impacts of daily variation loading rates are discussed. Copies of the source code and executable program are available free of charge.

Colt, J.; Watten, B.; Rust, M.

2009-01-01

202

The Headache of Carbon Dioxide Exposures  

NASA Technical Reports Server (NTRS)

Carbon dioxide (CO2), a natural product of human metabolism, accumulates quickly in sealed environments when humans are present, and can induce headaches, among other symptoms. Major resources are expended to control CO2 levels to concentrations that are tolerable to the crews of spacecraft and submersible craft. It is not practical to control CO2 levels to those found in the ambient environment on earth. As NASA looks ahead to long-duration missions conducted far from earth, difficult issues arise related to the management and effects of human exposure to CO2. One is the problem of pockets of CO2 in the habitat caused by excess generation of the gas in one location without a mechanism to purge the area with fresh air. This results in the crew rebreathing CO2 from their exhaled breath, exposing them to a much higher concentration of CO2 than whole-module measurements would suggest. Another issue is the potential increased sensitivity to CO2 in microgravity. For example, based on anecdotal information, it appears that space crews may be more susceptible than submarine crews to some of the subtle, yet adverse effects of CO2 exposure. Another issue, not unique to spaceflight, is the possibility of inter-individual differences in the susceptibility of crewmembers to CO2 exposure. Again, anecdotal reports from the International Space Station (ISS) crews suggest that certain individuals may experience a greater susceptibility. The implications associated with these issues are extremely important as NASA sets CO2 exposure limits that protect the crew from this compound s subtle adverse effects, without causing an unwarranted expenditure of resources to scrub CO2 from the habitat atmosphere.

James, John T.

2007-01-01

203

Transport of Carbon Dioxide and Radioactive Waste  

Microsoft Academic Search

\\u000a A comparative assessment of carbon dioxide (CO2) and radioactive waste transport systems associated with electricity generation was undertaken on the basis of 15 criteria\\u000a grouped under three areas, namely the transport chain, policy aspects and state of the technology. For CO2, we considered exclusively the transport that would take place under a future large-scale capture and storage infrastructure.\\u000a Our study

Darío R. Gómez; Michael Tyacke

204

Solubility of triacylglycerols in supercritical carbon dioxide  

Microsoft Academic Search

The solubility of refined corn and sunflower seed oils, babassu (Attalea funifera) and ucuuba (Virola sebifera) fats in supercritical carbon dioxide (SC-CO2) were measured in a temperature range from 40 to 80°C and pressure between 200 and 350bar. Under working conditions, the values of solubility showed retrograde behavior. Experimental SC-CO2 solubility data were collected from the literature for the following

B. M. C. Soares; F. M. C. Gamarra; L. C. Paviani; L. A. G. Gonçalves; F. A. Cabral

2007-01-01

205

Electrochemical carbon dioxide concentrator: Math model  

NASA Technical Reports Server (NTRS)

A steady state computer simulation model of an Electrochemical Depolarized Carbon Dioxide Concentrator (EDC) has been developed. The mathematical model combines EDC heat and mass balance equations with empirical correlations derived from experimental data to describe EDC performance as a function of the operating parameters involved. The model is capable of accurately predicting performance over EDC operating ranges. Model simulation results agree with the experimental data obtained over the prediction range.

Marshall, R. D.; Schubert, F. H.; Carlson, J. N.

1973-01-01

206

Carbon dioxide in Arctic and subarctic regions  

SciTech Connect

A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

Gosink, T. A.; Kelley, J. J.

1981-03-01

207

Carbon dioxide reduction by the Bosch process  

NASA Technical Reports Server (NTRS)

Prototype units for carrying out the reduction of carbon dioxide to elementary carbon have been built and operated successfully. In some cases, however, startup difficulties have been reported. Moreover, the recycle reactor product has been reported to contain only small amounts of water and undesirably high yields of methane. This paper presents the results of the first phase of an experimental study that was carried out to define the mechanisms occurring in the reduction process. Conclusions are drawn and possible modifications to the present recycle process are suggested.

Manning, M. P.; Reid, R. C.

1975-01-01

208

Carbon Dioxide Aquariums Greenhouse Gas Lesson  

NSDL National Science Digital Library

This classroom activity looks at carbon dioxide and its role in climate change. Students will perform an in-class experiment using aquariums. CO2 gas will be added to one aquarium, and measurements are taken of both aquariums over a one or two week period. This lesson includes step by step instructions on carrying out the experiment. The unit is a good introduction to the concepts of the carbon cycle, heat transfer, energy flow in ecosystems, the human impact on ecosystems and climate, non-renewable energy, resource consumption and pollution. This document may be downloaded in PDF file format. A class worksheet is included with the document.

Orzali, Joe

2009-01-01

209

Carbon dioxide sensitivity of zeolitic imidazolate frameworks.  

PubMed

Zeolitic imidazolate frameworks of zinc, cobalt, and cadmium, including the framework ZIF-8 commercially sold as Basolite Z1200, exhibit surprising sensitivity to carbon dioxide under mild conditions. The frameworks chemically react with CO2 in the presence of moisture or liquid water to form carbonates. This effect, which has been previously not reported in metal-organic framework chemistry, provides an explanation for conflicting reports on ZIF-8 stability to water and is of outstanding significance for evaluating the potential applications of metal-organic frameworks, especially for CO2 sequestration. PMID:24889776

Mottillo, Cristina; Friš?i?, Tomislav

2014-07-14

210

Carbon dioxide clouds in an early dense Martian atmosphere  

NASA Astrophysics Data System (ADS)

We use a time-dependent, microphysical cloud model to study the formation of carbon dioxide clouds in the Martian atmosphere. Laboratory studies by Glandorf et al. [2002] show that high critical supersaturations are required for CO2 cloud particle nucleation and that surface kinetic growth is not limited. These conditions, which are similar to those for cirrus clouds on Earth, lead to the formation of carbon dioxide ice particles with radii greater than 500 ?m and concentrations less than 0.1 cm-3 for typical atmospheric conditions. Within the current Martian atmosphere, CO2 cloud formation is possible at the poles during winter and possibly at high altitudes in the tropics. In both cases, temperature perturbations of several degrees below the CO2 saturation temperature are required to nucleate new cloud particles, suggesting that dynamical processes are the most common initiators of carbon dioxide clouds rather than diabatic cooling. The microphysical cloud model, coupled to a two-stream radiative transfer model, is used to reexamine the impact of CO2 clouds on the surface temperature within a dense CO2 atmosphere. The formation of carbon dioxide clouds leads to a warmer surface than what would be expected for clear sky conditions, but it also warms the atmosphere. The amount of surface warming is sensitive to the presence of dust and water vapor in the atmosphere, both of which act to dampen cloud effects. The radiative warming of the atmosphere associated with cloud formation, as well as latent heating, work to dissipate the clouds when present. In these simulations, clouds never last for periods much longer than several days, limiting their overall effectiveness for warming the surface. The time average cloud optical depth is approximately unity leading to a 5-10 K surface warming, depending on the surface pressure. The surface temperature does not rise above the freezing point of liquid water even for pressures as high as 5 bars, at a solar luminosity of 75% the current value. Our model shows that warming of the surface-atmosphere system by carbon dioxide clouds is self-limiting, since by heating the air the clouds cause themselves to dissipate. However, further analysis of the climatic effects of carbon dioxide clouds considering their global distribution and properties is warranted.

Colaprete, Anthony; Toon, Owen B.

2003-04-01

211

Carbon dioxide clouds in an early dense Martian atmosphere  

NASA Astrophysics Data System (ADS)

We use a time dependent, microphysical cloud model to study the formation of carbon dioxide clouds in the Martian atmosphere. Laboratory studies by Glandorf et al. (2002) show that high critical supersaturations are required for cloud particle nucleation and that surface kinetic growth is not limited. These conditions, which are similar to those for cirrus clouds on Earth, lead to the formation of carbon dioxide ice particles with radii greater than 500 ?m and concentrations less than 0.1 cm-3 for typical atmospheric conditions. Within the current Martian atmosphere, CO2 cloud formation is possible at the poles during winter and possibly at high altitudes in the tropics. In both cases, temperature perturbations of several degrees below the CO2 saturation temperature are required to nucleate new cloud particles suggesting that dynamical processes are the most common initiators of carbon dioxide clouds rather than diabatic cooling. The microphysical cloud model, coupled to a two-stream radiative transfer model, is used to reexamine the impact of CO2 clouds on the surface temperature within a dense CO2 atmosphere. The formation of carbon dioxide clouds leads to a warmer surface than what would be expected for clear sky conditions, but it also warms the atmosphere. The amount of surface warming is sensitive to the presence of dust and water vapor in the atmosphere, both of which act to dampen cloud effects. The radiative warming of the atmosphere associated with cloud formation, as well as latent heating, work to dissipate the clouds when present. In these simulations, clouds never last for periods much longer than several days, limiting their overall effectiveness for warming the surface. The time average cloud optical depth is approximately unity leading to a 5 - 10 K surface warming, depending on the surface pressure. The surface temperature does not rise above the freezing point of liquid water even for pressures as high as 5 bars, at a solar luminosity of 75% the current value. Our model shows that warming of the surface-atmosphere system by carbon dioxide clouds is self-limiting, since by heating the air the clouds cause themselves to dissipate. However, further analysis of the climatic effects of carbon dioxide clouds considering their global distribution and properties is warranted.

Colaprete, A.; Toon, O. B.

2002-12-01

212

Direct carbon dioxide emissions from civil aircraft  

NASA Astrophysics Data System (ADS)

Global airlines consume over 5 million barrels of oil per day, and the resulting carbon dioxide (CO2) emitted by aircraft engines is of concern. This article provides a contemporary review of the literature associated with the measures available to the civil aviation industry for mitigating CO2 emissions from aircraft. The measures are addressed under two categories - policy and legal-related measures, and technological and operational measures. Results of the review are used to develop several insights into the challenges faced. The analysis shows that forecasts for strong growth in air-traffic will result in civil aviation becoming an increasingly significant contributor to anthropogenic CO2 emissions. Some mitigation-measures can be left to market-forces as the key-driver for implementation because they directly reduce airlines' fuel consumption, and their impact on reducing fuel-costs will be welcomed by the industry. Other mitigation-measures cannot be left to market-forces. Speed of implementation and stringency of these measures will not be satisfactorily resolved unattended, and the current global regulatory-framework does not provide the necessary strength of stewardship. A global regulator with ‘teeth' needs to be established, but investing such a body with the appropriate level of authority requires securing an international agreement which history would suggest is going to be very difficult. If all mitigation-measures are successfully implemented, it is still likely that traffic growth-rates will continue to out-pace emissions reduction-rates. Therefore, to achieve an overall reduction in CO2 emissions, behaviour change will be necessary to reduce demand for air-travel. However, reducing demand will be strongly resisted by all stakeholders in the industry; and the ticket price-increases necessary to induce the required reduction in traffic growth-rates place a monetary-value on CO2 emissions of approximately 7-100 times greater than other common valuations. It is clear that, whilst aviation must remain one piece of the transport-jigsaw, environmentally a global regulator with ‘teeth' is urgently required.

Grote, Matt; Williams, Ian; Preston, John

2014-10-01

213

Elevated atmospheric carbon dioxide increases soil carbon  

SciTech Connect

In a study funded by the U.S. Department of Energy's Office of Science, researchers from Argonne and Oak Ridge National Laboratories and Kansas State and Texas A&M Universities evaluated the collective results of earlier studies by using a statistical procedure called meta-analysis. They found that on average elevated CO2 increased soil carbon by 5.6 percent over a two to nine year period. They also measured comparable increases in soil carbon for Tennessee deciduous forest and Kansas grassland after five to eight years of experimental exposure to elevated CO2.

Norby, Richard J [ORNL; Jastrow, Julie D [ORNL; Miller, Michael R [ORNL; Matamala, Roser [Argonne National Laboratory (ANL); Boutton, Thomas W [Texas A& M University; Rice, Charles W [ORNL; Owensby, Clenton E [Kansas State University

2005-01-01

214

Atmospheric Carbon Dioxide and Carbon Reservoir Changes  

Microsoft Academic Search

The net release of CO2 from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 × 109 tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th

Minze Stuiver

1978-01-01

215

Carbon dioxide disposal in carbonate minerals  

Microsoft Academic Search

We introduce a safe and permanent method of CO2 disposal based on combining CO2 chemically with abundant raw materials to form stable carbonate minerals. Substantial heat is liberated in the overall chemical reaction so that cost will be determined by the simplicity and speed of the reaction rather than the cost of energy. Preliminary investigations have been conducted on two

Klaus S. Lackner; Christopher H. Wendt; Darryl P. Butt; Edward L. Joyce; David H. Sharp

1995-01-01

216

Elevated atmospheric carbon dioxide increases soil carbon  

Microsoft Academic Search

In a study funded by the U.S. Department of Energy's Office of Science, researchers from Argonne and Oak Ridge National Laboratories and Kansas State and Texas A&M Universities evaluated the collective results of earlier studies by using a statistical procedure called meta-analysis. They found that on average elevated CO2 increased soil carbon by 5.6 percent over a two to nine

Richard J Norby; Michael R Miller; Roser Matamala; THOMAS W. BOUTTON; CHARLES W. RICE; CLENTON E. OWENSBY

2005-01-01

217

Changes in Strawberry Anthocyanins and Other Polyphenols in Response to Carbon Dioxide Treatments  

Microsoft Academic Search

Carbon dioxide-enriched atmospheres are used to reduce the incidence and severity of decay and to extend the postharvest life of strawberries. The influence of CO2 on the postharvest quality parameters of strawberries, particularly the stability of anthocyanins and other phenolic compounds, was investigated. Freshly harvested strawberries were placed in jars ventilated continuously with air or air enriched with 10%, 20%,

Maria I. Gil; Deirdre M. Holcroft; Adel A. Kader

1997-01-01

218

Automated carbon dioxide cleaning system  

NASA Technical Reports Server (NTRS)

Solidified CO2 pellets are an effective blast media for the cleaning of a variety of materials. CO2 is obtained from the waste gas streams generated from other manufacturing processes and therefore does not contribute to the greenhouse effect, depletion of the ozone layer, or the environmental burden of hazardous waste disposal. The system is capable of removing as much as 90 percent of the contamination from a surface in one pass or to a high cleanliness level after multiple passes. Although the system is packaged and designed for manual hand held cleaning processes, the nozzle can easily be attached to the end effector of a robot for automated cleaning of predefined and known geometries. Specific tailoring of cleaning parameters are required to optimize the process for each individual geometry. Using optimum cleaning parameters the CO2 systems were shown to be capable of cleaning to molecular levels below 0.7 mg/sq ft. The systems were effective for removing a variety of contaminants such as lubricating oils, cutting oils, grease, alcohol residue, biological films, and silicone. The system was effective on steel, aluminum, and carbon phenolic substrates.

Hoppe, David T.

1991-01-01

219

Carbon dioxide: A substitute for phosgene  

SciTech Connect

One of the many goals of the green chemistry movement is to eliminate the use of phosgene (COCl{sub 2}), an extremely hazardous compound used in many syntheses, including the production of carbamates, organic carbonates, and polymers. One of the most interesting options for eliminating this compound is to replace it with CO{sub 2}. In addition to carbon dioxide`s abundance and benign nature, it has the benefits of recycling carbon and of reducing the amount of CO{sub 2} released into the atmosphere when its use is linked with other processes that emit CO{sub 2}. Several synthetic strategies that do not use phosgene are under development. The authors briefly review the most interesting ones and then expand on the use of CO{sub 2} as a potential building block for organic carbamates, carbonates, and isocyanates. One of these routes, polycarbonate synthesis, is already in industrial-scale operation: PAC Polymers Inc. currently produces CO{sub 2}-epoxide copolymers. The synthesis of carbamates and substituted ureas has been developed, and this process awaits industrial exploitation.

Aresta, M.; Quaranta, E. [Univ. of Bari (Italy)

1997-03-01

220

Methane-carbon dioxide-nitrogen mixtures as a fuel  

SciTech Connect

The presence of diluents such as carbon dioxide or nitrogen with methane is often encountered to varying proportions in numerous natural, industrial and bio-gases. The paper discusses how such a presence modifies significantly the thermo-dynamic, kinetic and combustion characteristics of methane in air. Experimental results are presented showing how the performance of engines of the spark ignition type are adversely affected by increasing the presence of diluents with the methane. The bases for these trends are discussed and some guidelines towards alleviating these adverse effects are made.

Karim, G.A.; Wierzba, I. [Univ. of Calgary, Alberta (Canada). Dept. of Mechanical Engineering

1996-10-01

221

Carbon Dioxide Transport through Membranes*  

PubMed Central

Several membrane channels, like aquaporin-1 (AQP1) and the RhAG protein of the rhesus complex, were hypothesized to be of physiological relevance for CO2 transport. However, the underlying assumption that the lipid matrix imposes a significant barrier to CO2 diffusion was never confirmed experimentally. Here we have monitored transmembrane CO2 flux (JCO2) by imposing a CO2 concentration gradient across planar lipid bilayers and detecting the resulting small pH shift in the immediate membrane vicinity. An analytical model, which accounts for the presence of both carbonic anhydrase and buffer molecules, was fitted to the experimental pH profiles using inverse problems techniques. At pH 7.4, the model revealed that JCO2 was entirely rate-limited by near-membrane unstirred layers (USL), which act as diffusional barriers in series with the membrane. Membrane tightening by sphingomyelin and cholesterol did not alter JCO2 confirming that membrane resistance was comparatively small. In contrast, a pH-induced shift of the CO2 hydration-dehydration equilibrium resulted in a relative membrane contribution of about 15% to the total resistance (pH 9.6). Under these conditions, a membrane CO2 permeability (3.2 ± 1.6 cm/s) was estimated. It indicates that cellular CO2 uptake (pH 7.4) is always USL-limited, because the USL size always exceeds 1 ?m. Consequently, facilitation of CO2 transport by AQP1, RhAG, or any other protein is highly unlikely. The conclusion was confirmed by the observation that CO2 permeability of epithelial cell monolayers was always the same whether AQP1 was overexpressed in both the apical and basolateral membranes or not. PMID:18617525

Missner, Andreas; Kügler, Philipp; Saparov, Sapar M.; Sommer, Klaus; Mathai, John C.; Zeidel, Mark L.; Pohl, Peter

2008-01-01

222

Robust carbon dioxide reduction on molybdenum disulphide edges.  

PubMed

Electrochemical reduction of carbon dioxide has been recognized as an efficient way to convert carbon dioxide to energy-rich products. Noble metals (for example, gold and silver) have been demonstrated to reduce carbon dioxide at moderate rates and low overpotentials. Nevertheless, the development of inexpensive systems with an efficient carbon dioxide reduction capability remains a challenge. Here we identify molybdenum disulphide as a promising cost-effective substitute for noble metal catalysts. We uncover that molybdenum disulphide shows superior carbon dioxide reduction performance compared with the noble metals with a high current density and low overpotential (54?mV) in an ionic liquid. Scanning transmission electron microscopy analysis and first principle modelling reveal that the molybdenum-terminated edges of molybdenum disulphide are mainly responsible for its catalytic performance due to their metallic character and a high d-electron density. This is further experimentally supported by the carbon dioxide reduction performance of vertically aligned molybdenum disulphide. PMID:25073814

Asadi, Mohammad; Kumar, Bijandra; Behranginia, Amirhossein; Rosen, Brian A; Baskin, Artem; Repnin, Nikita; Pisasale, Davide; Phillips, Patrick; Zhu, Wei; Haasch, Richard; Klie, Robert F; Král, Petr; Abiade, Jeremiah; Salehi-Khojin, Amin

2014-01-01

223

Effects of carbon dioxide on Penicillium chrysogenum: an autoradiographic study  

SciTech Connect

Previous research has shown that dissolved carbon dioxide causes significant changes in submerged penicillin fermentations, such as stunted, swollen hyphae, increased branching, lower growth rates, and lower penicillin productivity. Influent carbon dioxide levels of 5 and 10% were shown through the use of autoradiography to cause an increase in chitin synthesis in submerged cultures of Penicillium chrysogenum. At an influent 5% carbon dioxide level, chitin synthesis is ca. 100% greater in the subapical region of P. chrysogenum hyphae than that of the control, in which there was no influent carbon dioxide. Influent carbon dioxide of 10% caused an increase of 200% in chitin synthesis. It is believed that the cell wall must be plasticized before branching can occur and that high amounts of dissolved carbon dioxide cause the cell to lose control of the plasticizing effect, thus the severe morphological changes occur.

Edwards, A.G.; Ho, C.S.

1988-06-20

224

Robust carbon dioxide reduction on molybdenum disulphide edges  

NASA Astrophysics Data System (ADS)

Electrochemical reduction of carbon dioxide has been recognized as an efficient way to convert carbon dioxide to energy-rich products. Noble metals (for example, gold and silver) have been demonstrated to reduce carbon dioxide at moderate rates and low overpotentials. Nevertheless, the development of inexpensive systems with an efficient carbon dioxide reduction capability remains a challenge. Here we identify molybdenum disulphide as a promising cost-effective substitute for noble metal catalysts. We uncover that molybdenum disulphide shows superior carbon dioxide reduction performance compared with the noble metals with a high current density and low overpotential (54?mV) in an ionic liquid. Scanning transmission electron microscopy analysis and first principle modelling reveal that the molybdenum-terminated edges of molybdenum disulphide are mainly responsible for its catalytic performance due to their metallic character and a high d-electron density. This is further experimentally supported by the carbon dioxide reduction performance of vertically aligned molybdenum disulphide.

Asadi, Mohammad; Kumar, Bijandra; Behranginia, Amirhossein; Rosen, Brian A.; Baskin, Artem; Repnin, Nikita; Pisasale, Davide; Phillips, Patrick; Zhu, Wei; Haasch, Richard; Klie, Robert F.; Král, Petr; Abiade, Jeremiah; Salehi-Khojin, Amin

2014-07-01

225

Enriching blast furnace gas by removing carbon dioxide.  

PubMed

Blast furnace gas (BF gas) produced in the iron making process is an essential energy resource for a steel making work. As compared with coke oven gas, the caloric value of BF gas is too low to be used alone as fuel in hot stove because of its high concentrations of carbon dioxide and nitrogen. If the carbon dioxide in BF gas could be captured efficiently, it would meet the increasing need of high caloric BF gas, and develop methods to reusing and/or recycling the separated carbon dioxide further. Focused on this, investigations were done with simple evaluation on possible methods of removing carbon dioxide from BF gas and basic experiments on carbon dioxide capture by chemical absorption. The experimental results showed that in 100 minutes, the maximum absorbed doses of carbon dioxide reached 20 g/100 g with ionic liquid as absorbent. PMID:25078829

Zhang, Chongmin; Sun, Zhimin; Chen, Shuwen; Wang, Baohai

2013-12-01

226

Carbon Dioxide and the Greenhouse Effect: A Problem Evaluation Activity.  

ERIC Educational Resources Information Center

Describes exercises to examine the global carbon cycle. Students are asked to predict consequences of increased carbon dioxide emissions into the atmosphere and to suggest ways to mitigate problems associated with these higher levels of atmospheric carbon dioxide. A comparison modeling exercise examines some of the variables related to the success…

Brewer, Carol A.; Beiswenger, Jane M.

1993-01-01

227

Carbon Dioxide Addition to Microbial Fuel Cell Cathodes Maintains  

E-print Network

Carbon Dioxide Addition to Microbial Fuel Cell Cathodes Maintains Sustainable Catholyte p losses and, therefore, power losses. Here, we report that adding carbon dioxide (CO2) gas to the cathodeH imbalances in contrast to the CO2/carbonate buffered catholyte system by Torres,Lee,andRittmann[Environ. Sci

Angenent, Lars T.

228

FRONTIERS ARTICLE On the hydration and hydrolysis of carbon dioxide  

E-print Network

FRONTIERS ARTICLE On the hydration and hydrolysis of carbon dioxide Alice H. England a,b , Andrew M August 2011 a b s t r a c t The dissolution of carbon dioxide in water and the ensuing hydrolysis, and hydration strength. Ã? 2011 Elsevier B.V. All rights reserved. 1. Introduction The hydrolysis of carbon

Cohen, Ronald C.

229

Research Spotlight: Rain modifies ocean-atmosphere carbon dioxide exchange  

NASA Astrophysics Data System (ADS)

Exchanges of carbon dioxide (CO2) between the atmosphere and the oceans play an important role in the global carbon cycle and in determining how much CO2 is stored in the atmosphere and how much is stored in the ocean. A new study shows that rain can be an important, though often overlooked, factor in this exchange. Rain can contribute to the air-sea carbon exchange in several ways. Rain dilutes the CO2 in the surface layer of the ocean, increases the speed at which gas is transferred between the atmosphere and ocean, and deposits carbon from the atmosphere into the ocean. To determine the effects of rain on the air-sea carbon flux in the western equatorial Pacific, Turk et al. analyzed rain measurements from a buoy at 0°, 156°E during 2002 as well as a dilution model based on observational ocean studies and output from an ocean carbon cycle model. (Geophysical Research Letters, doi:10.1029/2010GL045520, 2010)

Tretkoff, Ernie

2011-01-01

230

Caffeine solubility in supercritical carbon dioxide\\/co-solvent mixtures  

Microsoft Academic Search

In order to assess the effect of co-solvents on the solubility of caffeine in supercritical carbon dioxide, experimental solubility of caffeine in supercritical ethanol–carbon dioxide and isopropanol–carbon dioxide mixed solvents was obtained using a high-pressure semi-continuous flow apparatus. Caffeine solubilities in 5% ethanol\\/95% CO2, 10% ethanol\\/90% CO2 and 5% isopropanol\\/95% CO2 mixed solvents were determined at 323.2 and 343.2K and

Uiram Kopcak; Rahoma Sadeg Mohamed

2005-01-01

231

Carbon dioxide exchange and early old-field succession  

Microsoft Academic Search

Old-field succession is a widespread process active in shaping landscapes in the eastern United States, contributing significantly to the terrestrial sink of atmospheric carbon dioxide, particularly at midlatitudes. However, few studies document ecosystem-scale carbon dioxide exchange during the early years of old-field succession, particularly during the temporal transition from cultivation to abandonment. Rates of carbon dioxide exchange were measured for

Ryan E. Emanuel; John D. Albertson; Howard E. Epstein; Christopher A. Williams

2006-01-01

232

Supercritical carbon dioxide: a solvent like no other  

PubMed Central

Summary Supercritical carbon dioxide (scCO2) could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs). Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity. PMID:25246947

Peach, Jocelyn

2014-01-01

233

Upgrading carbon dioxide by incorporation into heterocycles.  

PubMed

Carbon dioxide is commonly regarded as the primary greenhouse gas, but from a synthetic standpoint can be utilized as an alternative and sustainable C1 synthon in organic synthesis rather than a waste. This results in the production of organic carbonates, carboxylic acids, and derivatives. Recently, CO2 has emerged as an appealing tool for heterocycle synthesis under mild conditions without using stoichiometric amounts of organometallic reducing reagents. This Minireview summarizes recent advances on methodologies for CO2 incorporation into N-, O-, and C-nucleophiles to provide various heterocycles, including cyclic carbamates, benzoxazine-2-one, 4-hydroxyquinolin-2-one, quinazoline-2,4(1?H,3?H)-diones, benzimidazolones, ?-alkylidene cyclic carbonate. PMID:25209543

Yu, Bing; He, Liang-Nian

2015-01-01

234

Carbon dioxide absorbent and method of using the same  

SciTech Connect

In accordance with one aspect, the present invention provides a composition which contains the amino-siloxane structures I, or III, as described herein. The composition is useful for the capture of carbon dioxide from process streams. In addition, the present invention provides methods of preparing the amino-siloxane composition. Another aspect of the present invention provides methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention, as species which react with carbon dioxide to form an adduct with carbon dioxide.

Perry, Robert James; O'Brien, Michael Joseph

2014-06-10

235

PHOTOCHEMICAL REACTIONS AMONG FORMALDEHYDE, CHLORINE, AND NITROGEN DIOXIDE IN AIR  

EPA Science Inventory

Photochemical reactions among chlorine, nitrogen dioxide, and formaldehyde were studied, using parts-per-million concentrations in 1 atm of air. The reactant mixtures were irradiated by ultraviolet fluorescent lamps and simultaneously analyzed by the Fourier transform infrared te...

236

Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures  

PubMed Central

Changes in host plant quality, including foliar amino acid concentrations, resulting from global climate change and attack from multiple herbivores, have the potential to modify the pest status of insect herbivores. This study investigated how mechanically simulated root herbivory of lucerne (Medicago sativa) before and after aphid infestation affected the pea aphid (Acyrthosiphon pisum) under elevated temperature (eT) and carbon dioxide concentrations (eCO2). eT increased plant height and biomass, and eCO2 decreased root C:N. Foliar amino acid concentrations and aphid numbers increased in response to eCO2, but only at ambient temperatures, demonstrating the ability of eT to negate the effects of eCO2. Root damage reduced aboveground biomass, height, and root %N, and increased root %C and C:N, most probably via decreased biological nitrogen fixation. Total foliar amino acid concentrations and aphid colonization success were higher in plants with roots cut early (before aphid arrival) than those with roots cut late (after aphid arrival); however, this effect was counteracted by eT. These results demonstrate the importance of amino acid concentrations for aphids and identify individual amino acids as being potential factors underpinning aphid responses to eT, eCO2, and root damage in lucerne. Incorporating trophic complexity and multiple climatic factors into plant–herbivore studies enables greater insight into how plants and insects will interact in the future, with implications for sustainable pest control and future crop security. PMID:25403916

Ryalls, James M. W.; Moore, Ben D.; Riegler, Markus; Gherlenda, Andrew N.; Johnson, Scott N.

2015-01-01

237

Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures.  

PubMed

Changes in host plant quality, including foliar amino acid concentrations, resulting from global climate change and attack from multiple herbivores, have the potential to modify the pest status of insect herbivores. This study investigated how mechanically simulated root herbivory of lucerne (Medicago sativa) before and after aphid infestation affected the pea aphid (Acyrthosiphon pisum) under elevated temperature (eT) and carbon dioxide concentrations (eCO2). eT increased plant height and biomass, and eCO2 decreased root C:N. Foliar amino acid concentrations and aphid numbers increased in response to eCO2, but only at ambient temperatures, demonstrating the ability of eT to negate the effects of eCO2. Root damage reduced aboveground biomass, height, and root %N, and increased root %C and C:N, most probably via decreased biological nitrogen fixation. Total foliar amino acid concentrations and aphid colonization success were higher in plants with roots cut early (before aphid arrival) than those with roots cut late (after aphid arrival); however, this effect was counteracted by eT. These results demonstrate the importance of amino acid concentrations for aphids and identify individual amino acids as being potential factors underpinning aphid responses to eT, eCO2, and root damage in lucerne. Incorporating trophic complexity and multiple climatic factors into plant-herbivore studies enables greater insight into how plants and insects will interact in the future, with implications for sustainable pest control and future crop security. PMID:25403916

Ryalls, James M W; Moore, Ben D; Riegler, Markus; Gherlenda, Andrew N; Johnson, Scott N

2015-02-01

238

Displacement of crude oil by carbon dioxide  

E-print Network

that passed through the core. Seeson and Ortloff conducted a laboratory study in which they investigated the oil recovery from displacing some high and low viscosity crudes from linear sandstone models. A 400 cp Ada crude oil was displaced from linear... Topedo sandstone and a 6 cp Loudon crude oil was displaced from linear models of Weiler sand- stone at 70 F and at about 1000 psi by water propelled carbon dioxide slugs. They found that the displacement technique was more efficient than waterflooding...

Omole, Olusegun

2012-06-07

239

Sigmoid perforation by compressed carbon dioxide.  

PubMed

Self-induced injuries of the bowel have various accidental mechanisms. This is a report of a 35-year-old patient with disruption of the recto-sigmoid junction caused by carbon dioxide (CO2) originating from a bottle of sparkling wine, which was introduced transanally for sexual stimulation. The patient underwent resection of the recto-sigmoid junction and primary anastomosis. The postoperative course was uneventful except for wound infection. The patient was discharged 12 days later. The physical backgrounds, the pathological pathways for perforation and diagnostic modalities including diagnostic pitfalls are critically discussed. PMID:15932178

Ikapischke, Matthias; Tepel, Juergen; Pai, Muhdra; Schulz, Tim

2005-03-01

240

Searching for clues to ancient carbon dioxide  

SciTech Connect

Something on Earth just won't stop fiddling with the thermostat. In the past 500 million years, the planet has shivered through ice ages lasting millions of years and sweltered through episodes of global warmth. Climatologists, eager to know what keeps jiggling the planet's temperature setting, have focused their suspicions on carbon dioxide, the same heat-trapping gas expected to drive up temperatures in coming decades. Catching this suspect in the act has been difficult, however; the atmospheres of millions of years ago are gone with the wind.

Appenzeller, T.

1993-02-12

241

Electrochemical carbon dioxide concentrator subsystem development  

NASA Technical Reports Server (NTRS)

The fabrication of a one-person Electrochemical Depolarized Carbon Dioxide Concentrator subsystem incorporating advanced electrochemical, mechanical, and control and monitor instrumentation concepts is discussed. This subsystem included an advanced liquid cooled unitized core composite cell module and integrated electromechanical components. Over 1800 hours with the subsystem with removal efficiencies between 90%. and 100%; endurance tests with a Fluid Control Assembly which integrates 11 gas handling components of the subsystem; and endurance testing of a coolant control assembly which integrates a coolant pump, diverter valve and a liquid accumulator were completed.

Heppner, D. B.; Dahlausen, M. J.; Schubert, F. H.

1983-01-01

242

Capture of carbon dioxide by hybrid sorption  

DOEpatents

A composition, process and system for capturing carbon dioxide from a combustion gas stream. The composition has a particulate porous support medium that has a high volume of pores, an alkaline component distributed within the pores and on the surface of the support medium, and water adsorbed on the alkaline component, wherein the proportion of water in the composition is between about 5% and about 35% by weight of the composition. The process and system contemplates contacting the sorbent and the flowing gas stream together at a temperature and for a time such that some water remains adsorbed in the alkaline component when the contact of the sorbent with the flowing gas ceases.

Srinivasachar, Srivats

2014-09-23

243

A Vortex Contactor for Carbon Dioxide Separations  

SciTech Connect

Many analysts identify carbon dioxide (CO2) capture and separation as a major roadblock in efforts to cost effectively mitigate greenhouse gas emissions via sequestration. An assessment 4 conducted by the International Energy Agency (IEA) Greenhouse Gas Research and Development Programme cited separation costs from $35 to $264 per tonne of CO2 avoided for a conventional coal fired power plant utilizing existing capture technologies. Because these costs equate to a greater than 40% increase in current power generation rates, it appears obvious that a significant improvement in CO2 separation technology is required if a negative impact on the world economy is to be avoided.

Raterman, Kevin Thomas; Mc Kellar, Michael George; Turner, Terry Donald; Podgorney, Anna Kristine; Stacey, Douglas Edwin; Stokes, B.; Vranicar, J.

2001-05-01

244

The kinetics of binding carbon dioxide in magnesium carbonate  

SciTech Connect

Humans currently consume about 6 Gigatons of carbon annually as fossil fuel. In some sense, the coal industry has a unique advantage over many other anthropogenic and natural emitters of CO{sub 2} in that it owns large point sources of CO{sub 2} from which this gas could be isolated and disposed of. If the increased energy demands of a growing world population are to be satisfied from coal, the implementation of sequestration technologies will likely be unavoidable. The authors` method of sequestration involves binding carbon dioxide as magnesium carbonate, a thermodynamically stable solid, for safe and permanent disposal, with minimal environmental impact. The technology is based on extracting magnesium hydroxide from common ultramafic rock for thermal carbonation and subsequent disposition. The economics of the method appear to be promising, however, many details of the proposed process have yet to be optimized. Realization of a cost effective method requires development of optimal technologies for efficient extraction and thermal carbonation.

Butt, D.P.; Lackner, K.S.; Wendt, C.H.; Vaidya, R.; Pile, D.L.; Park, Y.; Holesinger, T.; Harradine, D.M. [Los Alamos National Lab., NM (United States); Nomura, Koji [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.]|[Chichibu Onada Cement Co., Tokyo (Japan)

1998-08-01

245

The lifetime of excess atmospheric carbon dioxide  

SciTech Connect

Since the beginning of the industrial revolution human activity has significantly altered biogeochemical cycling on a global scale. The uncertainties of future climate change rests partly on issues of physical-climate system dynamics and their representation in general circulation models. However understanding the carbon cycle is a key to comprehending the changing terrestrial biosphere and to developing a reasonable range of future concentrations of greenhouse gases. The authors look at correction of model uncertainties in the examination of the lifetime of carbon dioxide. The two difficulties analysed are as follows: (1) most model-derived estimates of the relaxation of the concentration of CO2 reveal a function which is not always well approximated by weighted sums of exponentials; (2) the function c(t) is quite sensitive to assumptions about the terrestrial biosphere and the relaxation experiment. 51 refs., 15 figs., 7 tabs.

Moore, B. III; Braswell, B.H. (Univ. of New Hampshire, Durham, NH (United States))

1994-03-01

246

21 CFR 868.1150 - Indwelling blood carbon dioxide partial pressure (PCO2) analyzer.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Indwelling blood carbon dioxide partial pressure (PCO2...Diagnostic Devices § 868.1150 Indwelling blood carbon dioxide partial pressure (PCO2... (a) Identification. An indwelling blood carbon dioxide partial pressure...

2010-04-01

247

46 CFR 167.45-45 - Carbon dioxide fire extinguishing system requirements.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide fire extinguishing system requirements...Prevention Requirements § 167.45-45 Carbon dioxide fire extinguishing system requirements. (a) When a carbon dioxide (CO2 ) smothering...

2014-10-01

248

46 CFR 97.37-9 - Carbon dioxide and clean agent alarms.  

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Carbon dioxide and clean agent alarms. 97.37-9...Emergency Equipment, Etc. § 97.37-9 Carbon dioxide and clean agent alarms. Each carbon dioxide or clean agent fire extinguishing...

2014-10-01

249

46 CFR 196.37-9 - Carbon dioxide and clean agent alarms.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Carbon dioxide and clean agent alarms. 196...Equipment, etc. § 196.37-9 Carbon dioxide and clean agent alarms. Each extinguishing system using carbon dioxide or clean agent complying...

2014-10-01

250

49 CFR 195.4 - Compatibility necessary for transportation of hazardous liquids or carbon dioxide.  

Code of Federal Regulations, 2014 CFR

...transportation of hazardous liquids or carbon dioxide. 195.4 Section 195.4...transportation of hazardous liquids or carbon dioxide. No person may transport any hazardous liquid or carbon dioxide unless the hazardous liquid...

2014-10-01

251

46 CFR 78.47-9 - Carbon dioxide and clean agent alarms.  

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Carbon dioxide and clean agent alarms. 78.47-9...Emergency Equipment, Etc. § 78.47-9 Carbon dioxide and clean agent alarms. Each carbon dioxide or clean agent fire extinguishing...

2014-10-01

252

46 CFR 78.47-9 - Carbon dioxide and clean agent alarms.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Carbon dioxide and clean agent alarms. 78.47-9...Emergency Equipment, Etc. § 78.47-9 Carbon dioxide and clean agent alarms. Each carbon dioxide or clean agent fire extinguishing...

2012-10-01

253

46 CFR 131.815 - Carbon dioxide and clean agent alarms.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Carbon dioxide and clean agent alarms. 131.815...Equipment and Emergency Equipment § 131.815 Carbon dioxide and clean agent alarms. Each carbon dioxide or clean agent fire extinguishing...

2013-10-01

254

Chemical Reactions in Supercritical Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Utilizing supercritical fluids as environmentally benign solvents for chemical synthesis is one of the new approaches in the "greening" of chemistry. Carbon dioxide is the most widely used gas for supercritical fluid studies because of its moderate critical constants, nontoxic nature, and availability in pure form. One unique property of supercritical carbon dioxide (sc-CO2) is its high solubility for fluorinated compounds. Thus sc-CO2 can be used to replace Freons that are conventionally used as solvents for synthesis of perfluoro-polymers. Another property of sc-CO2 is its miscibility with gases such as H2. Heterogeneous reactions involving these gases may become homogeneous reactions in sc-CO2. Reactions in sc-CO2 may offer several advantages including controlling phase behavior and products, increasing speed of reactions, and obtaining specific reaction channels. This paper describes the following nine types of chemical reactions reported in the literature utilizing sc-CO2 as a solvent to illustrate the unique properties of the supercritical fluid reaction systems: (i) hydrogenation and hydroformylation, (ii) synthesis of organometallic compounds, (iii) metal chelation and extraction, (iv) preparation of inorganic nanoparticles, (v) stereo-selectivity of lipase-catalyzed reactions, (vi) asymmetric catalytic hydrogenation, (vii) polymerization, (viii) Diels-Alder reaction, and (ix) free radical reactions.

Wai, Chien M.; Hunt, Fred; Ji, Min; Chen, Xiaoyuan

1998-12-01

255

Hydrodynamic Controls on Carbon Dioxide Efflux from Inland Waters  

NASA Astrophysics Data System (ADS)

Intensive research has been undertaken on carbon dioxide efflux from lakes, estuaries and oceans, but much less attention has been given to rivers and streams, especially lower order streams. River systems are often over-saturated with carbon dioxide and so tend to act as sources of carbon dioxide to the atmosphere. It has been thought that rivers act as pipes carrying this terrestrial carbon to the oceans. However, recent studies have shown that a significant amount of the carbon is reprocessed within the system in a series of transformations and losses. Fluvial evasion of carbon dioxide is now recognised to be a significant component of carbon cycles, however the factors controlling carbon dioxide efflux and its magnitude remain poorly understood and quantified. This research aims to quantify, and better understand the controls on, freshwater carbon dioxide evasion. Data are presented here from field measurements that commenced in Sept 2013 in two contrasting Scottish rivers: the River Kelvin which has a large (335 km.sq) part-urban catchment with predominantly non-peat soils and Drumtee Water, a small (9.6 km.sq) rural catchment of peat soils and agricultural land. Using a floating chamber with the headspace connected to an infrared gas analyser to measure changes in carbon dioxide concentration, efflux rates from 0.22 - 47.4 ?mol CO2/m.sq/sec were measured, these close to the middle of the range of previously reported values. At one site on the River Kelvin in May 2013 an influx of -0.61 - -3.53 ?mol CO2/m.sq/sec was recorded. Whereas previous research finds carbon dioxide efflux to increase with decreasing river size and a more organic-rich soil catchment, here the controls on carbon dioxide evasion are similar across the contrasting catchments. Carbon dioxide evasion shows seasonality, with maximum fluxes in the summer months being up to twice as high as the winter maxima. Linear regression demonstrates that evasion increases with increased flow velocity, water surface disturbance indicated by Froude number, and turbulent mixing indicated by Reynolds number. Similar relationships with season, flow velocity and turbulence have been reported previously, but there is little known about the mechanisms involved. When comparing spot carbon dioxide efflux measurements to river stage time series data, carbon dioxide efflux is more sensitive to an increase in stage at more turbulent measurement points. Further investigation of the mechanisms will be obtained by measurement of DIC concentration and isotopic composition to assess the controls of carbon source versus degassing, and the analysis of the interactions between hydraulic and seasonal controls and carbon dioxide fluxes extended.

Long, H. E.; Waldron, S.; Hoey, T.; Newton, J.; Quemin, S.

2013-12-01

256

Sources and sinks of carbon dioxide in the Arctic regions  

SciTech Connect

The data base required to adequately ascertain seasonal source and sink strengths in the arctic regions is difficult to obtain. However, there are now a reasonable quantity of data for this polar region to estimate sources and sinks within the Arctic which may contribute significantly to the annual tropospheric CO/sub 2/ concentration fluctuation. The sea-ice-air and the sea-air interfaces account for most of the contribution to the sources and sinks for carbon dioxide. Although the arctic and subarctic region is small in extent, it certainly is not impervious and ice sealed. Our estimate, based on historical data and current research, indicates that the Arctic, which is about 4% of the earth's surface, is an annual net sink for approx. 10/sup 15/ g CO/sub 2/ accounting for an equivalent of approx. 3% of the annual anthropogenic contribution of CO/sub 2/ to the troposphere.

Gosink, T. A.; Kelley, J. J.

1982-01-01

257

Mechanistical studies on the formation of carbon dioxide in extraterrestrial carbon monoxide ice analog samples  

E-print Network

Mechanistical studies on the formation of carbon dioxide in extraterrestrial carbon monoxide ice with extraterrestrial, carbon monoxide bearing ices. The chemical modifications were monitored on line and in situ via of carbon monoxide and on the formation of carbon dioxide in extraterrestrial ice analog samples. 1

Kaiser, Ralf I.

258

Carbon dioxide emission during forest fires ignited by lightning  

E-print Network

In this paper we developed the model for the carbon dioxide emission from forest fire. The master equation for the spreading of the carbon dioxide to atmosphere is the hyperbolic diffusion equation. In the paper we study forest fire ignited by lightning. In that case the fores fire has the well defined front which propagates with finite velocity.

Pelc, Magdalena

2009-01-01

259

Carbon Dioxide, Global Warming, and Michael Crichton's "State of Fear"  

E-print Network

Carbon Dioxide, Global Warming, and Michael Crichton's "State of Fear" Bert W. Rust Mathematical- tioned the connection between global warming and increasing atmospheric carbon dioxide by pointing out of these plots to global warming have spilled over to the real world, inviting both praise [4, 17] and scorn [15

Rust, Bert W.

260

Carbon Dioxide and Global Warming: A Failed Experiment  

ERIC Educational Resources Information Center

Global warming is a current environmental issue that has been linked to an increase in anthropogenic carbon dioxide in the atmosphere. To raise awareness of the problem, various simple experiments have been proposed to demonstrate the effect of carbon dioxide on the planet's temperature. This article describes a similar experiment, which…

Ribeiro, Carla

2014-01-01

261

49 CFR 173.217 - Carbon dioxide, solid (dry ice).  

Code of Federal Regulations, 2013 CFR

(a) Carbon dioxide, solid (dry ice), when offered for transportation or transported by aircraft or water, must be packed in packagings designed and constructed to permit the release of carbon dioxide gas to prevent a buildup of pressure that could rupture the...

2013-10-01

262

21 CFR 868.5300 - Carbon dioxide absorbent.  

Code of Federal Regulations, 2013 CFR

A carbon dioxide absorbent is a device intended for medical purposes that consists of an absorbent material (e.g., soda lime) that is intended to remove carbon dioxide from the gases in the breathing circuit. (b) Classification. Class I (general...

2013-04-01

263

21 CFR 868.5310 - Carbon dioxide absorber.  

Code of Federal Regulations, 2013 CFR

A carbon dioxide absorber is a device that is intended for medical purposes and that is used in a breathing circuit as a container for carbon dioxide absorbent. It may include a canister and water drain. (b) Classification. Class I (general...

2013-04-01

264

Climate Science in a Nutshell: Where Carbon Dioxide Come From?  

NSDL National Science Digital Library

This short video discusses where carbon dioxide, the gas that is mainly responsible for warming up our planet and changing the climate, comes from. It discusses how the rise in atmospheric carbon dioxide comes directly from the burning of fossil fuels and indirectly from the human need for energy.

Planet Nutshell

265

Promising flame retardant textile in supercritical carbon dioxide  

Technology Transfer Automated Retrieval System (TEKTRAN)

Since carbon dioxide is non-toxic, non-flammable and cost-effective, supercritical carbon dioxide (scCO2) is widely used in textile dyeing applications. Due to its environmentally benign character, scCO2 is considered in green chemistry as a substitute for organic solvents in chemical reactions. O...

266

Blended polymer materials extractable with supercritical carbon dioxide  

Microsoft Academic Search

Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a

Mei Cai

1999-01-01

267

Urban Evapotranspiration and Carbon Dioxide Flux in Miami - Dade, Florida  

Microsoft Academic Search

Atmospheric Carbon Dioxide (CO2) concentrations are leading indicators of secular climate change. With increasing awareness of the consequences of climate change, methods for monitoring this change are becoming more important daily. Of particular interest is the carbon dioxide exchange between natural and urban landscapes and the correlation of atmospheric CO2 concentrations. Monitoring Evapotranspiration (ET) is important for assessments of water

T. Bernier; W. Hopper

2010-01-01

268

Irreversible climate change due to carbon dioxide emissions  

Microsoft Academic Search

The severity of damaging human-induced climate change depends not only on the magnitude of the change but also on the potential for irreversibility. This paper shows that the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative

Susan Solomon; Gian-Kasper Plattner; Reto Knutti; Pierre Friedlingstein

2009-01-01

269

Carbon dioxide sequestration by ex-situ mineral carbonation  

SciTech Connect

The process developed for carbon dioxide sequestration utilizes a slurry of water mixed with olivine- forsterite end member (Mg{sub 2}SiO{sub 4}), which is reacted with supercritical CO{sub 2} to produce magnesite (MgCO{sub 3}). Carbon dioxide is dissolved in water to form carbonic acid, which likely dissociates to H{sup +} and HCO{sub 3}{sup -}. The H{sup +} hydrolyzes the silicate mineral, freeing the cation (Mg{sup 2+}), which reacts with the HCO{sub 3}{sup -} to form the solid carbonate. Results of the baseline tests, conducted on ground products of the natural mineral, have demonstrated that the kinetics of the reaction are slow at ambient temperature (22 degrees C) and subcritical CO{sub 2} pressures (below 7.4 MPa). However, at elevated temperature and pressure, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant conversion to the carbonate occurs. Extent of reaction is roughly 90% within 24 h, at 185 degrees C and partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 11.6 MPa. Current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, and/or solution modification. Subsequent tests are intended to examine these options, as well as other mineral groups.

O'Connor, W.K.; Dahlin, D.C.; Turner, P.C.; and Walters, R.P.

2000-01-01

270

Carbon dioxide stripping in aquaculture. part 1: terminology and reporting  

USGS Publications Warehouse

The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ? H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (<2000 ?eq/kg), the difference between the true and apparent removal is small and can be ignored for many applications. Analytical and reporting standards are recommended to improve our understanding of carbon dioxide removal.

Colt, John; Watten, Barnaby; Pfeiffer, Tim

2012-01-01

271

ORNL/CDIAC-143 CARBON DIOXIDE, HYDROGRAPHIC, AND CHEMICAL DATA OBTAINED DURING THE  

E-print Network

Kozyr Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Oak Ridge, Tennessee, U Prepared by the Carbon Dioxide Information Analysis Center OAK RIDGE NATIONAL LABORATORY Oak Ridge

272

Does free-air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different seasons? A chlorophyll fluorescence study of mature loblolly pine  

SciTech Connect

Previous studies of the effects of growth at elevated CO{sup 2} on energy partitioning in the photosynthetic apparatus have produced conflicting results. The hypothesis was developed and tested that elevated CO{sub 2} increases photochemical energy use when there is a high demand for assimilates and decreases usage when demand is low. Modulated chlorophyll a fluorescence and leaf gas exchange were measured on needles at the tope of a mature, 12-m loblolly pine (Pinus taeda L.l) forest. Trees were exposed to ambient CO{sub 2} or ambient plus 20 Pa CO{sub 2} using free-air CO{sub 2} enrichment. During April and August, periods of shoot growth, light-saturated photo-synthesis and linear electron transport were increased by elevated CO{sub 2}. In November, when growth had ceased but temperatures were still moderate, CO{sub 2} treatment had no significant effect on linear electron transport. In February, when low temperatures were likely to inhibit translocation, CO{sub 2} treatment caused a significant decrease in linear electron transport. This coincided with a slower recovery of the maximum photosystem II efficiency on transfer of needles to the shade, indicating that growth in elevated CO{sub 2} induced a more persistent photoinhibition. Both the summer increase and the winter decrease in linear electron transport in elevated CO{sub 2} resulted from a change in photochemical quenching, not in the efficiency of energy transfer within the photosystem II antenna. There was no evidence of any effect of CO{sub 2} on photochemical energy sinks other than carbon metabolism. Their results suggest that elevated CO{sub 2} may increase the effects of winter stress on evergreen foliage.

Hymus, G.J.; Ellsworth, D.S.; Baker, N.R.; Long, S.P.

1999-08-01

273

Detectability and significance of the 12h barometric tide in the radon-222 signal, dripwater flow rate, carbon dioxide concentration and air temperature of an underground laboratory.  

NASA Astrophysics Data System (ADS)

Radon concentration has been measured since 1995 in the Roselend dead-end tunnel, in the French Alps, together with other geophysical and geochemical parameters. Bursts of radon concentration, reaching 65,600 Bq m-3 and up to several weeks duration, are observed over a background level of ca. 800 Bq m-3. These bursts appear to be related to the bedrock deformation or to the hydrogeological processes associated with the yearly cycle of water level in the nearby artificial Roselend Lake. In order to work out a generation mechanism, for these bursts, we developed tools to characterize the transport properties in the host rocks. Here, we concentrate on the 12h (S2) barometric tide. We first show, using real radon time series integrating synthetic signals, that a modified spectrogram method is more efficient than simple FFT to evidence weak periodic signals in such a context. Then, we apply this method to the radon concentration in the tunnel atmosphere measured by two different sensors: the AlphaGUARDTM sensor based on volumetric detection in an ionizing chamber, and the BarasolTM sensor, based on surface detection. Using the time series recorded by the AlphaGUARDTM, the S2 line, difficult to see with a simple FFT method, emerges clearly with our spectrogram method. This S2 line is not seen using the BarasolTM time series, illustrating the superior sensitivity of the AlphaGUARDTM for this particular purpose. Using a regular spectrogram analysis, we further show that the amplitude of the S2 line in the AlphaGUARDTM data depends on time, and appears particularly strong during the radon bursts. The presence of the S2 line reveals a high sensitivity of radon exhalation flux from the tunnel wall to changes of atmospheric pressure, and thus supports the advective transport mechanism for the radon bursts. A small but clear S2 component is also evidenced using our spectrogram method in a dripwater flow rate time series, representing a flow averaged over a 6 m2 area of the tunnel ceiling, while it is not observed in the flow rate of a more localized dripping. This suggests that some water drippings can also be affected by atmospheric pressure variations. The temporal structures of the S2 component in the flow rate and in the radon concentration, however, are not similar, indicating that water dripping from the ceiling cannot be the dominant source mechanism for the radon bursts. No S2 component is observed in the time series of carbon dioxide, but an interesting pattern is revealed by the S2 component of a temperature profile in the atmosphere. This study illustrates how a refined analysis to extract the S2 component in various geophysical time series can provide interesting clues on the complex processes affecting transport of fluids in unsaturated fractured media under multiple influences.

Richon, P.; Perrier, F.; Pili, E.; Boudon, G.; Villemant, B.; Sabroux, J.

2007-12-01

274

Global carbon dioxide emissions from inland waters.  

PubMed

Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity. We obtain global CO2 evasion rates of 1.8(+0.25)(-0.25)? petagrams of carbon (Pg?C) per year from streams and rivers and 0.32(+0.52)(-0.26)? Pg?C?yr(-1) from lakes and reservoirs, where the upper and lower limits are respectively the 5th and 95th confidence interval percentiles. The resulting global evasion rate of 2.1?Pg?C?yr(-1) is higher than previous estimates owing to a larger stream and river evasion rate. Our analysis predicts global hotspots in stream and river evasion, with about 70 per cent of the flux occurring over just 20 per cent of the land surface. The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally. PMID:24256802

Raymond, Peter A; Hartmann, Jens; Lauerwald, Ronny; Sobek, Sebastian; McDonald, Cory; Hoover, Mark; Butman, David; Striegl, Robert; Mayorga, Emilio; Humborg, Christoph; Kortelainen, Pirkko; Dürr, Hans; Meybeck, Michel; Ciais, Philippe; Guth, Peter

2013-11-21

275

Demographic change and carbon dioxide emissions.  

PubMed

Relations between demographic change and emissions of the major greenhouse gas carbon dioxide (CO(2)) have been studied from different perspectives, but most projections of future emissions only partly take demographic influences into account. We review two types of evidence for how CO(2) emissions from the use of fossil fuels are affected by demographic factors such as population growth or decline, ageing, urbanisation, and changes in household size. First, empirical analyses of historical trends tend to show that CO(2) emissions from energy use respond almost proportionately to changes in population size and that ageing and urbanisation have less than proportional but statistically significant effects. Second, scenario analyses show that alternative population growth paths could have substantial effects on global emissions of CO(2) several decades from now, and that ageing and urbanisation can have important effects in particular world regions. These results imply that policies that slow population growth would probably also have climate-related benefits. PMID:22784534

O'Neill, Brian C; Liddle, Brant; Jiang, Leiwen; Smith, Kirk R; Pachauri, Shonali; Dalton, Michael; Fuchs, Regina

2012-07-14

276

Cooling Heat Transfer of Supercritical Carbon Dioxide  

NASA Astrophysics Data System (ADS)

The characteristics of carbon dioxide cooled under supercritical condition were investigated theoretically and experimentally. Based on the results of numerical calculation and experimental measurements described in the 1st report, a new correlation was proposed to predict the heat transfer coefficient, and the Filonenko's equation was found adequate to predict the pressure drop inside as mall seized tube. Those correlations were compared with measurement results and the deviations were found lower than ±20%. Furthermore, a compressor cycle was assembled to investigate the effect of lubricant oil on heat transfer and pressure drop. The oil content in CO2 was set to be about 0.5% during the measurements. This amount of lubricant oil was found affected the heat transfer coefficient significantly, with largest degradation of heat transfer coefficient at the pseudocritical point to nearly 50%. The effect of lubricant oil at small concentration on the pressure drop was found negligible.

Dang, Chaobin; Hihara, Eiji

277

Layered solid sorbents for carbon dioxide capture  

DOEpatents

A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

2014-11-18

278

Pulsed-discharge carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

The purpose is to attempt a general introduction to pulsed carbon dioxide lasers of the kind used or proposed for laser radar applications. Laser physics is an excellent example of a cross-disciplinary topic, and the molecular spectroscopy, energy transfer, and plasma kinetics of the devices are explored. The concept of stimulated emission and population inversions is introduced, leading on to the molecular spectroscopy of the CO2 molecule. This is followed by a consideration of electron-impact pumping, and the pertinent energy transfer and relaxation processes which go on. Since the devices are plasma pumped, it is necessary to introduce a complex subject, but this is restricted to appropriate physics of glow discharges. Examples of representative devices are shown. The implications of the foregoing to plasma chemistry and gas life are discussed.

Willetts, David V.

1990-01-01

279

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

This report describes research conducted between October 1, 2004 and December 31, 2004 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Two supported sorbents were tested in a bench scale fluidized bed reactor system. The sorbents were prepared by impregnation of sodium carbonate on to an inert support at a commercial catalyst manufacturing facility. One sorbent, tested through five cycles of carbon dioxide sorption in an atmosphere of 3% water vapor and 0.8 to 3% carbon dioxide showed consistent reactivity with sodium carbonate utilization of 7 to 14%. A second, similarly prepared material, showed comparable reactivity in one cycle of testing. Batches of 5 other materials were prepared in laboratory scale quantities (primarily by spray drying). These materials generally have significantly greater surface areas than calcined sodium bicarbonate. Small scale testing showed no significant adsorption of mercury on representative carbon dioxide sorbent materials under expected flue gas conditions.

David A. Green; Brian S. Turk; Jeffrey W. Portzer; Thomas Nelson; Raghubir P. Gupta

2005-01-01

280

Does carbon dioxide pool or stream in the subsurface?  

E-print Network

Pools of carbon dioxide are found in natural geological accumulations and in engineered storage in saline aquifers. It has been thought that once this CO2 dissolves in the formation water, making it denser, convection streams would transport it efficiently to depth, but this may not be so. Here, we assess the impact of natural chemical reactions between the dissolved CO2 and the rock formation on the convection streams in the subsurface. We show that, while in carbonate rocks the streaming of dissolved carbon dioxide persists, the chemical interactions in silicate-rich rocks may curb this transport drastically and even inhibit it altogether. New laboratory experiments confirm the curtailing of convection by reaction. Wide and narrow streams of dense carbon-rich water are shut-off gradually as reaction strength increases until all transport of the pooled carbon dioxide occurs by slow molecular diffusion. These results show that the complex fluid dynamic and kinetic interactions between pooled carbon dioxide an...

Cardoso, Silvana S S

2014-01-01

281

Coiled tubing drilling with supercritical carbon dioxide  

DOEpatents

A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO.sub.2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO.sub.2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC--CO.sub.2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC--CO.sub.2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC--CO.sub.2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC--CO.sub.2 much more effective than water jet erosion. SC--CO.sub.2 jets can be used to assist mechanical drilling, for erosion drilling, or for scale removal. A choke manifold at the well head or mud cap drilling equipment can be used to control the pressure within the borehole, to ensure that the temperature and pressure conditions necessary for CO.sub.2 to exist as either a supercritical fluid or a dense gas occur at the drill site. Spent CO.sub.2 can be vented to the atmosphere, collected for reuse, or directed into the formation to aid in the recovery of petroleum.

Kolle , Jack J. (Seattle, WA)

2002-01-01

282

Ozone, Air Quality, and Asthma (For Parents)  

MedlinePLUS

... gases such as carbon monoxide, sulfur dioxide, and nitrogen dioxide. High levels of these gases can also ... level ozone particle pollution carbon monoxide sulfur dioxide nitrogen dioxide Using a color-coded system, the Air ...

283

Carbon dioxide exchange and growth of a pine plantation  

SciTech Connect

The exchange of materials between the atmosphere and terrestrial ecosystem is important to an understanding of the cycling of essential elements, the deposition of mateials from the atmosphere and the entrance of pollutants into the forest ecosystems. This paper reports the results of measurements of carbon dioxide exchange in a vigorously growing pine plantation. Measurement data were incorporated into a model used to estimate annual carbon dioxide exchange and measured annual biomass accumulation in the same plantation were used to determine a carbon dioxide to biomass conversion efficiency. Carbon dioxide exchange was 10.5 metric tons per hectare and biomass accumulation was 4.5 metric tons per hectare. The conversion efficiency of cabon dioxide to biomass is about 25% less than the theoretical chemical conversion efficiency. 27 refs., 8 figs.

Murphy, Jr, C E

1981-01-01

284

The Potential of Clear Sky Carbon Dioxide Satellite Retrievals  

NASA Astrophysics Data System (ADS)

It has been shown that neglecting scattering and absorption by aerosols and thin clouds can lead to significant errors in retrievals of the column-averaged dry-air mole fraction of carbon dioxide (XCO2) from space-based measurements of near-infrared reflected sunlight. These clear sky retrievals, which assume no aerosol effects, are desirable because of their high computational efficiency relative to common full physics retrievals. Further, clear sky retrievals may be able to make higher quality measurements relative to the full physics approach because they may introduce fewer potential biases under certain circumstances. These biases can appear when we try to retrieve clouds and aerosols in the full physics methods when there are none actually present. Recent work has shown that intelligent pre-screening can remove soundings with large light-path modifications over ocean surfaces. In this work, we test the hypothesis that intelligent pre-screening of soundings may be successfully used over land surfaces as well as oceans, which would allow clear sky retrievals to be applicable over all surfaces. We also test the hypothesis that major light path modification effects associated with aerosols can be identified based on spectral tests at 0.76, 1.6, and 2 microns. This presentation summarizes our study of both simulated data and satellite observations from the GOSAT instrument in order to assess the effectiveness of using a clear sky retrieval algorithm coupled with intelligent pre-screening to accurately measure carbon dioxide from space-borne instruments.

Nelson, R.; O'Dell, C.

2013-12-01

285

Herbivore responses to plants grown in enriched carbon dioxide atmospheres  

SciTech Connect

Our initial study of sagebrush and grasshopper responses to elevated and historical carbon dioxide atmospheres is complete and has been accepted for publication. The study on Biomass Allocation Patterns of Defoliated Sagebrush Grown Under Two Levels of Carbon Dioxide has completed and the manuscript has been submitted for publication. We have completed the study of plant growth under two nutrient and carbon dioxide regimes and grasshopper feeding responses. The study of a specialist feeding caterpillar, the cabbage butterfly, and a mustard hostplant has recently been completed. We were able to identify the principal allelochemicals of the mustard plants, butenyl and pentenyl isothiocyanates, by combined gas chromatography and mass spectrometry. Measurement of these chemicals has been a critical component of this study since these compounds contain nitrogen and sulphur and act as a feeding stimulant to the caterpillar. This insect responds to elevated carbon dioxide by consuming more leaves and we can now say that this is not due to a change in the feeding stimulants. Reduced leaf protein content is a critical factor for even specialist feeding insect herbivores under elevated carbon dioxide conditions. The study on Grasshopper Population Responses to Enriched Carbon Dioxide Concentration is currently in progress at the Duke University Phytotron. We have changed hostplant species in order to complement the investigations of carbon dioxide effects on tallgrass prairie. Specifically, we are using big bluestem, Andropogon geradii, as the host plant to feed to the grasshoppers. This experiment will be completed in July 1990.

Lincoln, D.E.

1990-05-01

286

An advanced carbon reactor subsystem for carbon dioxide reduction  

NASA Technical Reports Server (NTRS)

An evaluation is presented of the development status of an advanced carbon-reactor subsystem (ACRS) for the production of water and dense, solid carbon from CO2 and hydrogen, as required in physiochemical air revitalization systems for long-duration manned space missions. The ACRS consists of a Sabatier Methanation Reactor (SMR) that reduces CO2 with hydrogen to form methane and water, a gas-liquid separator to remove product water from the methane, and a Carbon Formation Reactor (CFR) to pyrolize methane to carbon and hydrogen; the carbon is recycled to the SMR, while the produce carbon is periodically removed from the CFR. A preprototype ACRS under development for the NASA Space Station is described.

Noyes, Gary P.; Cusick, Robert J.

1986-01-01

287

The Effect of Atmospheric Carbon Dioxide Elevation on Plant Growth in Freshwater Ecosystems  

Microsoft Academic Search

We developed a dynamic model to investigate the effect of atmospheric carbon dioxide (CO 2) increase on plant growth in freshwater ecosystems. Steady-state simulations were performed to analyze the response of phytoplankton and submerged macrophytes to atmospheric CO 2 elevation from 350 to 700 ppm. We studied various conditions that may affect this response, such as alkalinity, the air–water exchange

Peter Schippers; Jan E. Vermaat; Jeroen de Klein; Wolf M. Mooij

2004-01-01

288

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

This report describes research conducted between April 1, 2005 and June 30, 2005 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas from coal combustion and synthesis gas from coal gasification. Supported sodium carbonate sorbents removed up to 76% of the carbon dioxide from simulated flue gas in a downflow cocurrent flow reactor system, with an approximate 15 second gas-solid contact time. This reaction proceeds at temperatures as low as 25 C. Lithium silicate sorbents remove carbon dioxide from high temperature simulated flue gas and simulated synthesis gas. Both sorbent types can be thermally regenerated and reused. The lithium silicate sorbent was tested in a thermogravimetric analyzer and in a 1-in quartz reactor at atmospheric pressure; tests were also conducted at elevated pressure in a 2-in diameter high temperature high pressure reactor system. The lithium sorbent reacts rapidly with carbon dioxide in flue gas at 350-500 C to absorb about 10% of the sorbent weight, then continues to react at a lower rate. The sorbent can be essentially completely regenerated at temperatures above 600 C and reused. In atmospheric pressure tests with synthesis gas of 10% initial carbon dioxide content, the sorbent removed over 90% of the carbon dioxide. An economic analysis of a downflow absorption process for removal of carbon dioxide from flue gas with a supported sodium carbonate sorbent suggests that a 90% efficient carbon dioxide capture system installed at a 500 MW{sub e} generating plant would have an incremental capital cost of $35 million ($91/kWe, assuming 20 percent for contingencies) and an operating cost of $0.0046/kWh. Assuming capital costs of $1,000/kW for a 500 MWe plant the capital cost of the down flow absorption process represents a less than 10% increase, thus meeting DOE goals as set forth in its Carbon Sequestration Technology Roadmap and Program Plan.

David A. Green; Thomas Nelson; Brian S. Turk; Paul Box; Weijiong Li; Raghubir P. Gupta

2005-07-01

289

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

This report describes research conducted between January 1, 2005 and March 31, 2005 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Engineered sorbents composed of sodium carbonate on a ceramic support were tested in a laboratory fluidized bed reactor system and found to be capable of essentially complete removal of carbon dioxide at 60 C in a short residence time. Upon breakthrough the sorbents can be thermally regenerated to recover essentially all of the absorbed carbon dioxide. An optimized supported sorbent tested in a pilot-scale entrained bed absorber retained its reactivity in multicycle tests and experienced no attrition. Removal of >90% of carbon dioxide in simulated flue gas was achieved in an entrained bed reactor.

David A. Green; Thomas Nelson; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta

2005-04-01

290

Carbon dioxide warming of the early Earth  

NASA Technical Reports Server (NTRS)

Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestrial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure.

Arrhenius, G.

1997-01-01

291

Carbon dioxide warming of the early Earth.  

PubMed

Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestrial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure. PMID:11541253

Arrhenius, G

1997-02-01

292

Forest management techniques for carbon dioxide storage  

SciTech Connect

In the global ecosystem concerning carbon dioxide content in the atmosphere, the forest ecosystem plays an important role. In effect, the ratio of forest biomass to total terrestrial biomass is about 90%, and the ratio of carbon stored in the forest biomass to that in the atmosphere is two thirds. When soils and detritus of forests are added, there is more C stored in forests than in the atmosphere, about 1.3 times or more. Thus, forests can be regarded as the great holder of C on earth. If the area of forest land on the earth is constantly maintained and forests are in the climax stage, the uptake of C and the release of C by and from the forests will balance. In this case, forests are neither sinks nor sources of CO{sub 2} although they store a large amount of C. However, when forests are deforested, they become a source of C; through human activities, forests have become a source of C. According to a report by the IPCC, 1.6{+-}1.2 PgC is annually added to the atmosphere by deforestation. According to the FAO (1992), the area of land deforested annually in the tropics from 1981 to 1990 was 16.9 x 10{sup 6} ha. This value is nearly half the area of Japanese land. The most important thing for the CO{sub 2} environment concerning forests is therefore how to reduce deforestation and to successfully implement a forestation or reforestation.

Fujimori, Takao [Forestry and Forest Products Research Inst., Tsukuba, Ibaraki (Japan)

1993-12-31

293

Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures  

DOEpatents

A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

Aines, Roger D.; Bourcier, William L.

2014-08-19

294

Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures  

DOEpatents

A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

Aines, Roger D. (Livermore, CA); Bourcier, William L. (Livermore, CA)

2010-11-09

295

Carbon dioxide euthanasia in rats: oxygen supplementation minimizes signs of agitation and asphyxia  

Microsoft Academic Search

Summary This paper records the effects of carbon dioxide when used for euthanasia, on behaviour, electrical brain activity and heart rate in rats. Four different methods were used. Animals were placed in a box (a) that was completely filled with carbon dioxide; (b) into which carbon dioxide was streamed at a high flow rate; leiinto which carbon dioxide was streamed

A. M. L. Coenen; W. H. I. M. Drinkenburgl; R. Hoenderken; E. L. J. M. van Luijtelaar

1995-01-01

296

Separation of Carbon Monoxide and Carbon Dioxide for Mars ISRU  

NASA Technical Reports Server (NTRS)

The atmosphere of Mars has many resources that can be processed to produce things such as oxygen, fuel, buffer gas, and water for support of human exploration missions. Successful manipulation of these resources is crucial for safe, cost-effective, and self-sufficient long-term human exploration of Mars. In our research, we are developing enabling technologies that require fundamental knowledge of adsorptive gas storage and separation processes. In particular, we are designing and constructing an innovative, low mass, low power separation device to recover carbon dioxide and carbon monoxide for Mars ISRU (in-situ resource utilization). The technology has broad implications for gas storage and separations for gas-solid systems that are ideally suited for reduced gravitational environments. This paper describes our separation process design and experimental procedures and reports results for the separation of CO2 and CO by a four-step adsorption cycle.

Walton, Krista S.; LeVan, M. Douglas

2004-01-01

297

Thermal Infrared Radiation and Carbon Dioxide in the Atmosphere  

E-print Network

Thermal Infrared Radiation and Carbon Dioxide in the Atmosphere Bill Satzer 3M Company #12;Outline · Radiation spectra ­ incoming and outgoing · Physical setting ­ characteristics of the atmosphere · CO2 dioxide Water vapor #12;Atmospheric composition (parts per million by volume) · Nitrogen (N2) 780

Olver, Peter

298

Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures  

DOEpatents

A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

Aines, Roger D.; Bourcier, William L.; Viani, Brian

2013-01-29

299

Atmospheric response to deep-sea injections of fossil-fuel carbon dioxide  

Microsoft Academic Search

The possibility of controlling atmospheric carbon dioxide accumulation and attendant climatic effects from fossil-fuel burning by diverting a fraction of the combustion product and injecting it into the deep-ocean, as proposed by Marchetti, is analyzed using an atmosphere\\/mixed layer\\/diffusive deep-ocean model for the carbon cycle. The model includes the nonlinear buffering of CO2 at the air\\/sea interface, and considers the

Martin I. Hoffert; Yeong-Cherng Wey; Andrew J. Callegari; Wallace S. Broecker

1979-01-01

300

System-Level Analysis Modeling of Impacts of Operation Schemes of Geologic Carbon Dioxide Storage on Deep Groundwater and Carbon Dioxide Leakage Risk  

NASA Astrophysics Data System (ADS)

The objectives of this study are to predict quantitatively groundwater and carbon dioxide flow in deep saline sandstone aquifers under various carbon dioxide injection schemes (injection rate, injection period) and to analyze integratively impacts of such carbon dioxide injection schemes on deep groundwater (brine) and carbon dioxide leakage risk through abandoned wells or faults. In order to achieve the first objective, a series of process-level prediction modeling of groundwater and carbon dioxide flow in a deep saline sandstone aquifer under several carbon dioxide injection schemes was performed using a multiphase thermo-hydrological numerical model TOUGH2 (Pruess et al., 1999). The prediction modeling results show that the extent of carbon dioxide plume is significantly affected by such carbon dioxide injection schemes. In order to achieve the second objective, a series of system-level analysis modeling of deep groundwater and carbon dioxide leakage risk through an abandoned well or a fault under several carbon dioxide injection schemes was then performed using a brine and carbon dioxide leakage risk analysis model CO2-LEAK (Kim, 2012). The analysis modeling results show that the rates and amounts of deep groundwater and carbon dioxide leakage through an abandoned well or a fault increase as the carbon dioxide injection rate increases. However, the rates and amounts of deep groundwater and carbon dioxide leakage through an abandoned well or a fault decrease as the carbon dioxide injection period increases. These system-level analysis modeling results for deep groundwater and carbon dioxide leakage risk can be utilized as baseline data for establishing guidelines to mitigate anticipated environmental adverse effects on shallower groundwater systems (aquifers) when deep groundwater and carbon dioxide leakage occur. This work was supported by the Geo-Advanced Innovative Action (GAIA) Program funded by the Korea Environmental Industry and Technology Institute (KEITI), Ministry of Environment, Republic of Korea.

Park, S.; Lee, S.; Park, J.; Kim, J.; Kihm, J.

2013-12-01

301

Synthesis of Amides and Lactams in Supercritical Carbon Dioxide  

E-print Network

Supercritical carbon dioxide can be employed as an environmentally friendly alternative to conventional organic solvents for the synthesis of a variety of carboxylic amides. The addition of amines to ketenes generated in ...

Mak, Xiao Yin

302

World energy consumption and carbon dioxide emissions : 1950-2050  

E-print Network

Emissions of carbon dioxide form combustion of fossil fuels, which may contribute to long-term climate change, are projected through 2050 using reduced form models estimated with national-level panel data for the period ...

Schmalensee, Richard

1995-01-01

303

The oxygen and carbon dioxide balance in the earth's atmosphere  

NASA Technical Reports Server (NTRS)

The oxygen-carbon dioxide cycle is described in detail, and steps which are sensitive to perturbation or instability are identified. About half of the carbon dioxide consumption each year in photosynthesis occurs in the oceans. Phytoplankton, which are the primary producers, have been shown to assimilate insecticides and herbicides. The impact of such materials on phytoplankton photosynthesis, both direct and as the indirect result of detrimental effects higher up in the food chain, cannot be assessed. Net oxygen production is very small in comparison with the total production and occurs almost exclusively in a few ocean areas with anoxic bottom conditions and in peat-forming marshes which are sensitive to anthropogenic disturbances. The carbon dioxide content of the atmosphere is increasing at a relatively rapid rate as the result of fossil fuel combustion. Increases in photosynthesis as the result of the hothouse effect may in turn reduce the carbon dioxide content of the atmosphere, leading to global cooling.

Johnson, F. S.

1975-01-01

304

Atmospheric concentrations of carbon dioxide, methane and nitrous oxide  

NSDL National Science Digital Library

This is a figure from the 2007 IPCC Assessment Report 4 on atmospheric concentrations of carbon dioxide, methane and nitrous oxide over the last 10,000 years (large panels) and since 1750 (inset panels).

IPCC (Intergovernmental Panel of Climate Change)

305

Partitioning Carbon Dioxide and Water Vapor Fluxes Using Correlation Analysis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Partitioning of eddy covariance flux measurements is routinely done to quantify the contributions of separate processes to the overall fluxes. Measurements of carbon dioxide fluxes represent the difference between gross ecosystem photosynthesis and total respiration, while measurements of water vapo...

306

Control strategies for supercritical carbon dioxide power conversion systems  

E-print Network

The supercritical carbon dioxide (S-C02) recompression cycle is a promising advanced power conversion cycle which couples well to numerous advanced nuclear reactor designs. This thesis investigates the dynamic simulation ...

Carstens, Nathan, 1978-

2007-01-01

307

Separation of carbon dioxide from flue emissions using Endex principles  

E-print Network

In an Endex reactor endothermic and exothermic reactions are directly thermally coupled and kinetically matched to achieve intrinsic thermal stability, efficient conversion, autothermal operation, and minimal heat losses. Applied to the problem of in-line carbon dioxide separation from flue gas, Endex principles hold out the promise of effecting a carbon dioxide capture technology of unprecedented economic viability. In this work we describe an Endex Calcium Looping reactor, in which heat released by chemisorption of carbon dioxide onto calcium oxide is used directly to drive the reverse reaction, yielding a pure stream of carbon dioxide for compression and geosequestration. In this initial study we model the proposed reactor as a continuous-flow dynamical system in the well-stirred limit, compute the steady states and analyse their stability properties over the operating parameter space, flag potential design and operational challenges, and suggest an optimum regime for effective operation.

Ball, R

2009-01-01

308

Effect of Electronarcosis on Oxygen Consumption and Carbon Dioxide Output  

Microsoft Academic Search

IN assessing changes of vital function during electronarcosis, we measured oxygen consumption and carbon dioxide output in an experiment in rabbits. The measured values were considered an important index for the evaluation of metabolic changes during electronarcosis.

Jaroslav Strmiska; Antonín Vacek

1960-01-01

309

9 CFR 313.5 - Chemical; carbon dioxide.  

Code of Federal Regulations, 2014 CFR

...by the elimination of sharp projections or exposed wheels or gears. There shall be no unnecessary holes, spaces or openings...gas supplied to anesthesia chambers may be from controlled reduction of solid carbon dioxide or from a controlled liquid...

2014-01-01

310

DEVELOPMENT AND INTEGRATION OF NEW PROCESSES CONSUMING CARBON DIOXIDE IN  

E-print Network

............................................................... 3 B. Greenhouse Effect and Climate Change............................................. 4 1. Estimation of Greenhouse Gas Emissions....................................... 6 2. Greenhouse Gas Emissions........................................................ 8 C. Carbon Dioxide ­ A Greenhouse Gas................................................ 9 1. Sources

Pike, Ralph W.

311

Electrochemically-mediated amine regeneration for carbon dioxide separations  

E-print Network

This thesis describes a new strategy for carbon dioxide (CO?) separations based on amine sorbents, which are electrochemically-mediated to facilitate the desorption and regeneration steps of the separation cycle. The ...

Stern, Michael C. (Michael Craig)

2014-01-01

312

International Space Station Carbon Dioxide Removal Assembly (ISS CDRA) Concepts and Advancements  

NASA Technical Reports Server (NTRS)

An important aspect of air revitalization for life support in spacecraft is the removal of carbon dioxide from cabin air. Several types of carbon dioxide removal systems are in use in spacecraft life support. These systems rely on various removal techniques that employ different architectures and media for scrubbing CO2, such as permeable membranes, liquid amine, adsorbents, and absorbents. Sorbent systems have been used since the first manned missions. The current state of key technology is the existing International Space Station (ISS) Carbon Dioxide Removal Assembly (CDRA), a system that selectively removes carbon dioxide from the cabin atmosphere. The CDRA system was launched aboard UF-2 in February 2001 and resides in the U.S. Destiny Laboratory module. During the past four years, the CDRA system has operated with varying degrees of success. There have been several approaches to troubleshooting the CDRA system aimed at developing work-around solutions that would minimize the impact on astronaut time required to implement interim solutions. The paper discusses some of the short-term fixes applied to promote hardware life and restore functionality, as well as long-term plans and solutions for improving operability and reliability. The CDRA is a critical piece of life support equipment in the air revitalization system of the ISS, and is demonstrated technology that may ultimately prove well-suited for use in lunar or Mars base, and Mars transit life support applications.

ElSherif, Dina; Knox, James C.

2005-01-01

313

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2012 CFR

...ambient air quality standard for sulfur oxides (sulfur dioxide). 50.5 Section...ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The...shall be rounded up). (b) Sulfur oxides shall be measured in the ambient...

2012-07-01

314

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2013 CFR

...ambient air quality standard for sulfur oxides (sulfur dioxide). 50.5 Section...ambient air quality standard for sulfur oxides (sulfur dioxide). (a) The...shall be rounded up). (b) Sulfur oxides shall be measured in the ambient...

2013-07-01

315

Submarine seep of carbon dioxide in Norton Sound, Alaska  

USGS Publications Warehouse

Earlier workers have described a submarine gas seep in Norton Sound having an unusual mixture of petroleum-like, low-molecular-weight hydrocarbons. Actually, only about 0.04 percent of the seeping gas is hydrocarbons and 98 percent is carbon dioxide. The isotopic compositions of carbon dioxide (??13CPDB = -2.7 per mil) and methane (??13CPDB = -36 per mil, where PDB is the Peedee belemnite standard) indicate that geothermal processes are active here. Copyright ?? 1979 AAAS.

Kvenvolden, K.A.; Weliky, K.; Nelson, H.; Des Marais, D.J.

1979-01-01

316

Extraction of lemongrass essential oil with dense carbon dioxide  

Microsoft Academic Search

Lemongrass (Cymbopogon citratus) essential oil was extracted with dense carbon dioxide at 23–50°C and 85–120 bar. The composition of samples collected during the first and the last hours of the extraction experiments was analyzed by gas chromatography–mass spectrometry, and coextraction of cuticular waxes was observed. Liquid carbon dioxide extracts had a larger quantity of coextracted waxes than the supercritical extracts.

Luiz Henrique Castelan Carlson; Ricardo Antonio Francisco Machado; Cinthia Bittencourt Spricigo; Lia Krücken Pereira; Ariovaldo Bolzan

2001-01-01

317

Carbon dioxide in the ocean surface: The homogeneous buffer factor  

USGS Publications Warehouse

The amount of carbon dioxide that can be dissolved in surface seawater depends at least partially on the homogeneous buffer factor, which is a mathematical function of the chemical equilibrium conditions among the various dissolved inorganic species. Because these equilibria are well known, the homogeneous buffer factor is well known. Natural spatial variations depend very systematically on sea surface temperatures, and do not contribute significantly to uncertainties in the present or future carbon dioxide budget. Copyright ?? 1979 AAAS.

Sundquist, E.T.; Plummer, L.N.; Wigley, T.M.L.

1979-01-01

318

Methanolysis of seed oils in flowing supercritical carbon dioxide  

Microsoft Academic Search

The direct methanolysis of triglycerides in flowing supercritical carbon dioxide by an immobilized lipase is described. The\\u000a reaction system consists of two syringe pumps for substrate addition and another two syringe pumps for delivering CO2 at 24.1 MPa. Corn oil is pumped into the carbon dioxide stream at a rate of 4 ?L\\/min, and methanol is pumped at 5 ?L\\/min

Michael A. Jackson; Jerry W. King

1996-01-01

319

ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS DIETHANOLAMINE SOLUTIONS  

Microsoft Academic Search

The rates of absorption of pure carbon dioxide into aqueous diethanolamine solutions were measured at 25C in a liquid-jet column and a wetted-wall column. Experimental results were analyzed with the chemical absorption theory based on the penetration model. Physical solubility of carbon dioxide in aqueous diethanolamine solutions was determined from the absorption rates measured in a near pseudo first-order reaction

H. HIKITA; S. ASAI; H. ISHIKAWA; K. UKU

1980-01-01

320

Beneficial Use of Carbon Dioxide in Precast Concrete Production  

SciTech Connect

The feasibility of using carbon dioxide as feedstock in precast concrete production is studied. Carbon dioxide reacts with calcium compounds in concrete, producing solid calcium carbonates in binding matrix. Two typical precast products are examined for their capacity to store carbon dioxide during the production. They are concrete blocks and fiber?cement panels. The two products are currently mass produced and cured by steam. Carbon dioxide can be used to replace steam in curing process to accelerate early strength, improve the long?term durability and reduce energy and emission. For a reaction within a 24?hour process window, the theoretical maximum possible carbon uptake in concrete is found to be 29% based on cement mass in the product. To reach the maximum uptake, a special process is developed to promote the reaction efficiency to 60?80% in 4?hour carbon dioxide curing and improve the resistance to freeze?thaw cycling and sulfate ion attack. The process is also optimized to meet the project target of $10/tCO{sub 2} in carbon utilization. By the use of self?concentrating absorption technology, high purity CO{sub 2} can be produced at a price below $40/t. With low cost CO{sub 2} capture and utilization technologies, it is feasible to establish a network for carbon capture and utilization at the vicinity of carbon sources. If all block produces and panel producers in United States could adopt carbon dioxide process in their production in place of steam, carbon utilization in these two markets alone could consume more than 2 Mt CO{sub 2}/year. This capture and utilization process can be extended to more precast products and will continue for years to come.

Shao, Yixin

2014-03-31

321

Miniaturized Amperometric Solid Electrolyte Carbon Dioxide Sensors  

NASA Technical Reports Server (NTRS)

A miniaturized electrochemical carbon dioxide (CO2) sensor using Na3Z r2Si2PO12 (NASICON) as a solid electrolyte has been fabricated and de monstrated. Microfabrication techniques were used for sensor fabricat ion to yield a sensing area around 1.0 mm x 1.1 mm. The NASICON solid electrolyte and the Na2CO3/BaCO3 (1:1.7 molar ratio) auxiliary elect rolyte were deposited by sputtering in between and on top of the inte rdigitated finger-shaped platinum electrodes. This structure maximize s the length of the three-phase boundary (electrode, solid electrolyt e, and auxiliary electrolyte), which is critical for gas sensing. The robust CO2 sensor operated up to 600 C in an amperometric mode and a ttempts were made to optimize sensor operating parameters. Concentrat ions of CO2 between 0.02% and 4% were detected and the overall sensor performance was evaluated. Linear response of sensor current output to ln[CO2 concentration] ranging from 0.02% to 1% was achieved.

Hunter, G. W.; Xu, J. C.; Liu, C. C.; Hammond, J. W.; Ward, B.; Lukco, D.; Lampard, P.; Artale, M.; Androjna, D.

2006-01-01

322

Development of Carbon Dioxide Hermitic Compressor  

NASA Astrophysics Data System (ADS)

Because of global environmental problems, the existing refrigerants are to be replaced with natural refrigerants. CO2 is one of the natural refrigerants and environmentally safe, inflammable and non-toxic refrigerant. Therefore high efficiency compressor that can operate with natural refrigerants, especially CO2, needs to be developed. We developed a prototype CO2 hermetic compressor, which is able to use in carbon dioxide refrigerating systems for practical use. The compressor has two rolling pistons, and it leads to low vibrations, low noise. In additions, two-stage compression with two cylinders is adopted, because pressure difference is too large to compress in one stage. And inner pressure of the shell case is intermediate pressure to minimize gas leakage between compressing rooms and inner space of shell case. Intermediate pressure design enabled to make the compressor smaller in size and lighter in weight. As a result, the compressor achieved high efficiency and high reliability by these technology. We plan to study heat pump water heater, cup vending machine and various applications with CO2 compressor.

Imai, Satoshi; Oda, Atsushi; Ebara, Toshiyuki

323

Zenker's Diverticulum: Carbon Dioxide Laser Endoscopic Surgery  

PubMed Central

Nowadays endoscopic diverticulotomy is the surgical approach of the first choice in treatment of Zenker's diverticulum. We report our experience with this procedure and try to sum up recent recommendations for management of surgery and postoperative care. Data of 34 patients with Zenker's diverticulum, treated by endoscopic carbon dioxide laser diverticulotomy at the Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University, University Hospital Motol, Prague, Czech Republic, were prospectively stored and followed in relatively short period from May 2009 to December 2013. The average length of diverticulum was 32?mm. The average duration of surgery was 32?min. The patients were fed via feeding tube for 6.1 days and antibiotics were administered for 7 days. Mean hospitalization time was 7.4 days. We observed one transient recurrent laryngeal nerve paralysis and no other serious complications. Recurrence rate was 3%. We recommend complete transection of the diverticular septum in one procedure, systemic antibiotic treatment and exclusion of transoral intake for minimally 5 days, and contrast oesophagogram before resumption of oral intake to exclude fistula. Open diverticulectomy should be reserved for cases with inadequate endoscopic exposure and for revision surgery for multiple recurrences from endoscopic diverticulotomies. PMID:24729975

Plzák, Jan; Zábrodský, Michal; Lukeš, Petr

2014-01-01

324

Suppressing bullfrog larvae with carbon dioxide  

USGS Publications Warehouse

Current management strategies for the control and suppression of the American Bullfrog (Lithobates catesbeianus = Rana catesbeiana Shaw) and other invasive amphibians have had minimal effect on their abundance and distribution. This study evaluates the effects of carbon dioxide (CO2) on pre- and prometamorphic Bullfrog larvae. Bullfrogs are a model organism for evaluating potential suppression agents because they are a successful invader worldwide. From experimental trials we estimated that the 24-h 50% and 99% lethal concentration (LC50 and LC99) values for Bullfrog larvae were 371 and 549 mg CO2/L, respectively. Overall, larvae that succumbed to experimental conditions had a lower body condition index than those that survived. We also documented sublethal changes in blood chemistry during prolonged exposure to elevated CO2. Specifically, blood pH decreased by more than 0.5 pH units after 9 h of exposure and both blood partial pressure of CO2 (pCO2) and blood glucose increased. These findings suggest that CO2 treatments can be lethal to Bullfrog larvae under controlled laboratory conditions. We believe this work represents the necessary foundation for further consideration of CO2 as a potential suppression agent for one of the most harmful invaders to freshwater ecosystems.

Gross, Jackson A.; Ray, Andrew; Sepulveda, Adam J.; Watten, Barnaby J.; Densmore, Christine L.; Layhee, Megan J.; Mark Abbey-Lambert; Mark Abbey-Lambert

2014-01-01

325

Carbon dioxide balneotherapy and cardiovascular disease  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO2 baths in various cardiovascular diseases. The three main effects of CO2 hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO2 baths in other cardiovascular substrates is discussed.

Pagourelias, Efstathios D.; Zorou, Paraskevi G.; Tsaligopoulos, Miltiadis; Athyros, Vasilis G.; Karagiannis, Asterios; Efthimiadis, Georgios K.

2011-09-01

326

PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SUPERCRITICAL CARBON DIOXIDE TREATED AND AIR-CLASSIFIED OAT BRAN CONCENTRATE MICROWAVE-IRRADIATED IN SOLVENTS AT VARYING TEMPERATURES  

Technology Transfer Automated Retrieval System (TEKTRAN)

In addition to health-beneficial beta-glucans, oats contain phenolic compounds (PC) and other antioxidant activity (AA). We investigated processing technologies to produce oat ingredients with concentrated levels of PC and AA. Oat bran concentrate (OBC) had lipids removed by supercritical carbon d...

327

Study of the interactions of molten sodium nitrate-potassium nitrate 50 mol % mixture with water vapor and carbon dioxide in air. Final report, June 2, 1980-June 30, 1981  

SciTech Connect

The interactions of aerial components such as water, carbon dioxide, and oxygen with the binary 50 mol % mixture of sodium nitrate and potassium nitrate have been studied in the temperature range 300 to 600/sup 0/C using electrochemical methods. In addition, the behavior of nitrite ions in this melt was investigated electrochemically. By judicious choice of techniques, in situ electroanalysis was possible and the necessary relevant data to accomplish this is presented, as well as insight into the corresponding electrochemical mechanisms associated with the electroactive species. The influence of each atmospheric component was examined separately. At temperatures above 300/sup 0/C, nitrite ions are found to accumulate due to thermal decomposition of the nitrate. Water is highly soluble in the salt mixture, but no hydrolytic reactions were observed. Two methods of in situ analysis for water are described. Pure carbon dioxide is found to attack the melt at all temperatures above 250/sup 0/C producing carbonate. (LEW)

White, S.H.; Twardoch, U.M.

1981-09-01

328

The role of renewable bioenergy in carbon dioxide sequestration  

SciTech Connect

The use of renewable resources represents a sound approach to producing clean energy and reducing the dependence on diminishing reserves of fossil fuels. Unfortunately, the widespread interest in renewable energy in the 1970s, spurred by escalating fossil fuel prices, subsided with the collapse of energy prices in the mid 1980s. Today, it is largely to reverse alarming environmental trends, particularly the buildup of atmospheric carbon dioxide, rather than to reduce the cost of energy, that renewable energy resources are being pursued. This discussion focuses on a specific class of renewable energy resources - biomass. Unlike most other classes of renewable energy touted for controlling atmospheric carbon dioxide concentrations, e.g., hydro, direct solar, wind, geothermal, and ocean thermal, which produce usable forms of energy while generating little or no carbon dioxide emissions, bioenergy almost always involves combustion and therefore generates carbon dioxide; however, if used on a sustained basis, bio-energy would not contribute to the build-up of atmospheric carbon dioxide because the amount released in combustion would be balanced by that taken up via photosynthesis. It is in that context, i.e., sustained production of biomass as a modern energy carrier, rather than reforestation for carbon sequestration, that biomass is being discussed here, since biomass can play a much greater role in controlling global warming by displacing fossil fuels than by being used strictly for carbon sequestration (partly because energy crop production can reduce fossil carbon dioxide emissions indefinitely, whereas under the reforestation strategy, carbon dioxide abatement ceases at forest maturity).

Kinoshita, C.M. [Hawaii Natural Energy Inst., Honolulu, HI (United States)

1993-12-31

329

A 400 million year carbon isotope record of pedogenic carbonate: Implications for paleoatmospheric carbon dioxide  

Microsoft Academic Search

A 400 record of atmospheric carbon dioxide levels has been estimated by applying a COâ paleobarometer to a database of 758 analyses of paleosol (fossil soil) carbonates. This database is a compilation of new data and previously published values from the literature. Many new analyses of Mesozoic paleosols are reported, an era poorly represented in the literature. Results indicate that

D. D. Ekart; T. E. Cerling; I. P. Montanez; N. J. Tabor

1999-01-01

330

Carbon Dioxide-Water Emulsions for Enhanced Oil Recovery and Permanent Sequestration of Carbon Dioxide  

SciTech Connect

This project involves the use of an innovative new invention ? Particle Stabilized Emulsions (PSEs) of Carbon Dioxide-in-Water and Water-in-Carbon Dioxide for Enhanced Oil Recovery (EOR) and Permanent Sequestration of Carbon Dioxide. The EOR emulsion would be injected into a semi-depleted oil reservoir such as Dover 33 in Otsego County, Michigan. It is expected that the emulsion would dislocate the stranded heavy crude oil from the rock granule surfaces, reduce its viscosity, and increase its mobility. The advancing emulsion front should provide viscosity control which drives the reduced-viscosity oil toward the production wells. The make-up of the emulsion would be subsequently changed so it interacts with the surrounding rock minerals in order to enhance mineralization, thereby providing permanent sequestration of the injected CO{sub 2}. In Phase 1 of the project, the following tasks were accomplished: 1. Perform laboratory scale (mL/min) refinements on existing procedures for producing liquid carbon dioxide-in-water (C/W) and water-in-liquid carbon dioxide (W/C) emulsion stabilized by hydrophilic and hydrophobic fine particles, respectively, using a Kenics-type static mixer. 2. Design and cost evaluate scaled up (gal/min) C/W and W/C emulsification systems to be deployed in Phase 2 at the Otsego County semi-depleted oil field. 3. Design the modifications necessary to the present CO{sub 2} flooding system at Otsego County for emulsion injection. 4. Design monitoring and verification systems to be deployed in Phase 2 for measuring potential leakage of CO{sub 2} after emulsion injection. 5. Design production protocol to assess enhanced oil recovery with emulsion injection compared to present recovery with neat CO{sub 2} flooding. 6. Obtain Federal and State permits for emulsion injection. Initial research focused on creating particle stabilized emulsions with the smallest possible globule size so that the emulsion can penetrate even low-permeability crude oilcontaining formations or saline aquifers. The term ?globule? refers to the water or liquid carbon dioxide droplets sheathed with ultrafine particles dispersed in the continuous external medium, liquid CO{sub 2} or H{sub 2}O, respectively. The key to obtaining very small globules is the shear force acting on the two intermixing fluids, and the use of ultrafine stabilizing particles or nanoparticles. We found that using Kenics-type static mixers with a shear rate in the range of 2700 to 9800 s{sup -1} and nanoparticles between 100-300 nm produced globule sizes in the 10 to 20 ?m range. Particle stabilized emulsions with that kind of globule size should easily penetrate oil-bearing formations or saline aquifers where the pore and throat size can be on the order of 50 ?m or larger. Subsequent research focused on creating particle stabilized emulsions that are deemed particularly suitable for Permanent Sequestration of Carbon Dioxide. Based on a survey of the literature an emulsion consisting of 70% by volume of water, 30% by volume of liquid or supercritical carbon dioxide, and 2% by weight of finely pulverized limestone (CaCO{sub 3}) was selected as the most promising agent for permanent sequestration of CO{sub 2}. In order to assure penetration of the emulsion into tight formations of sandstone or other silicate rocks and carbonate or dolomite rock, it is necessary to use an emulsion consisting of the smallest possible globule size. In previous reports we described a high shear static mixer that can create such small globules. In addition to the high shear mixer, it is also necessary that the emulsion stabilizing particles be in the submicron size, preferably in the range of 0.1 to 0.2 ?m (100 to 200 nm) size. We found a commercial source of such pulverized limestone particles, in addition we purchased under this DOE Project a particle grinding apparatus that can provide particles in the desired size range. Additional work focused on attempts to generate particle stabilized emulsions with a flow through, static mixer based apparatus under a variety

Ryan, David; Golomb, Dan; Shi, Guang; Shih, Cherry; Lewczuk, Rob; Miksch, Joshua; Manmode, Rahul; Mulagapati, Srihariraju; Malepati, Chetankurmar

2011-09-30

331

Carbon Dioxide Reduction Technology Trade Study  

NASA Technical Reports Server (NTRS)

For long-term human missions, a closed-loop atmosphere revitalization system (ARS) is essential to minimize consumables. A carbon dioxide (CO2) reduction technology is used to reclaim oxygen (O2) from metabolic CO2 and is vital to reduce the delivery mass of metabolic O2. A key step in closing the loop for ARS will include a proper CO2 reduction subsystem that is reliable and with low equivalent system mass (ESM). Sabatier and Bosch CO2 reduction are two traditional CO2 reduction subsystems (CRS). Although a Sabatier CRS has been delivered to International Space Station (ISS) and is an important step toward closing the ISS ARS loop, it recovers only 50% of the available O2 in CO2. A Bosch CRS is able to reclaim all O2 in CO2. However, due to continuous carbon deposition on the catalyst surface, the penalties of replacing spent catalysts and reactors and crew time in a Bosch CRS are significant. Recently, technologies have been developed for recovering hydrogen (H2) from Sabatier-product methane (CH4). These include methane pyrolysis using a microwave plasma, catalytic thermal pyrolysis of CH4 and thermal pyrolysis of CH4. Further, development in Sabatier reactor designs based on microchannel and microlith technology could open up opportunities in reducing system mass and enhancing system control. Improvements in Bosch CRS conversion have also been reported. In addition, co-electrolysis of steam and CO2 is a new technology that integrates oxygen generation and CO2 reduction functions in a single system. A co-electrolysis unit followed by either a Sabatier or a carbon formation reactor based on Bosch chemistry could improve the overall competitiveness of an integrated O2 generation and CO2 reduction subsystem. This study evaluates all these CO2 reduction technologies, conducts water mass balances for required external supply of water for 1-, 5- and 10-yr missions, evaluates mass, volume, power, cooling and resupply requirements of various technologies. A system analysis and comparison among the technologies was made based on ESM, technology readiness level and reliability. Those technologies with potential were recommended for development.

Jeng, Frank F.; Anderson, Molly S.; Abney, Morgan B.

2011-01-01

332

Soil carbon dioxide partial pressure and dissolved inorganic carbonate chemistry under elevated carbon dioxide and ozone.  

PubMed

Global emissions of atmospheric CO(2) and tropospheric O(3) are rising and expected to impact large areas of the Earth's forests. While CO(2) stimulates net primary production, O(3) reduces photosynthesis, altering plant C allocation and reducing ecosystem C storage. The effects of multiple air pollutants can alter belowground C allocation, leading to changes in the partial pressure of CO(2) (pCO(2)) in the soil , chemistry of dissolved inorganic carbonate (DIC) and the rate of mineral weathering. As this system represents a linkage between the long- and short-term C cycles and sequestration of atmospheric CO(2), changes in atmospheric chemistry that affect net primary production may alter the fate of C in these ecosystems. To date, little is known about the combined effects of elevated CO(2) and O(3) on the inorganic C cycle in forest systems. Free air CO(2) and O(3) enrichment (FACE) technology was used at the Aspen FACE project in Rhinelander, Wisconsin to understand how elevated atmospheric CO(2) and O(3) interact to alter pCO(2) and DIC concentrations in the soil. Ambient and elevated CO(2) levels were 360+/-16 and 542+/-81 microl l(-1), respectively; ambient and elevated O(3) levels were 33+/-14 and 49+/-24 nl l(-1), respectively. Measured concentrations of soil CO(2) and calculated concentrations of DIC increased over the growing season by 14 and 22%, respectively, under elevated atmospheric CO(2) and were unaffected by elevated tropospheric O(3). The increased concentration of DIC altered inorganic carbonate chemistry by increasing system total alkalinity by 210%, likely due to enhanced chemical weathering. The study also demonstrated the close coupling between the seasonal delta(13)C of soil pCO(2) and DIC, as a mixing model showed that new atmospheric CO(2) accounted for approximately 90% of the C leaving the system as DIC. This study illustrates the potential of using stable isotopic techniques and FACE technology to examine long- and short-term ecosystem C sequestration. PMID:15378342

Karberg, N J; Pregitzer, K S; King, J S; Friend, A L; Wood, J R

2005-01-01

333

A selective and efficient electrocatalyst for carbon dioxide reduction  

NASA Astrophysics Data System (ADS)

Converting carbon dioxide to useful chemicals in a selective and efficient manner remains a major challenge in renewable and sustainable energy research. Silver is an interesting electrocatalyst owing to its capability of converting carbon dioxide to carbon monoxide selectively at room temperature; however, the traditional polycrystalline silver electrocatalyst requires a large overpotential. Here we report a nanoporous silver electrocatalyst that is able to electrochemically reduce carbon dioxide to carbon monoxide with approximately 92% selectivity at a rate (that is, current) over 3,000 times higher than its polycrystalline counterpart under moderate overpotentials of <0.50?V. The high activity is a result of a large electrochemical surface area (approximately 150 times larger) and intrinsically high activity (approximately 20 times higher) compared with polycrystalline silver. The intrinsically higher activity may be due to the greater stabilization of CO2?- intermediates on the highly curved surface, resulting in smaller overpotentials needed to overcome the thermodynamic barrier.

Lu, Qi; Rosen, Jonathan; Zhou, Yang; Hutchings, Gregory S.; Kimmel, Yannick C.; Chen, Jingguang G.; Jiao, Feng

2014-01-01

334

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

This report describes research conducted between April 1, 2004 and June 30, 2004 on the preparation and use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Support materials and supported sorbents were prepared by spray drying. Sorbents consisting of 20 to 50% sodium carbonate on a ceramic support were prepared by spray drying in batches of approximately 300 grams. The supported sorbents exhibited greater carbon dioxide capture rates than unsupported calcined sodium bicarbonate in laboratory tests. Preliminary process design and cost estimation for a retrofit application suggested that costs of a dry regenerable sodium carbonate-based process could be lower than those of a monoethanolamine absorption system. In both cases, the greatest part of the process costs come from power plant output reductions due to parasitic consumption of steam for recovery of carbon dioxide from the capture medium.

David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

2004-07-01

335

Electrical mobilities of multiply charged ionic-liquid nanodrops in air and carbon dioxide over a wide temperature range: influence of ion-induced dipole interactions.  

PubMed

The electrical mobilities of hundreds of mass-selected, multiply charged nanodrops (2-6 nm in diameter) of the ionic liquid EMI-BF4 have been measured in air and CO2 at temperatures, T, ranging from 20 to 100 °C, extending previous studies, based on EMI-N(CN)2 nanodrops in air at 20 °C, to other temperatures and drift gases. The known compressibility of EMI-BF4 removes prior slight ambiguities in the mass-based determination of nanodrop diameters. We confirm the previous finding that the collision cross-sections ? of these nanodrops, inferred from their electrical mobilities, are related to their diameters d via a relation of the form ? ? ??/4(d + d(g))(2) (1 + ??*) (1 + f(Kn))(-1), where ?* is the ratio between the polarization and thermal energies of the ion-gas molecule system at contact, f(Kn) is a continuum-correction that vanishes in the free-molecule limit, and the coefficients dg, ?, and ? are inferred experimentally as functions of temperature and drift gas. This expression for ?(d,z) enables determining true (geometric) cross-sections of globular ions from their measured electrical mobilities in molecular gases. We also corroborate prior reports that the drag-enhancement factor ?, which remains nearly constant with temperature and drift-gas, exceeds slightly the value ?m? 1.36 established by Millikan's oil drop measurements. Unexpectedly, the coefficient ? shows a significant temperature dependence, suggesting that the ion-gas molecule scattering process is affected by T. The effective gas-molecule collision diameter dg is seen to decrease with T, and takes a value in excess of 0.45 nm in CO2 at 20 °C, considerably larger than in room-temperature air. PMID:25141918

Fernández-García, Juan; de la Mora, Juan Fernández

2014-10-14

336

Interaction of Surface Modified Carbon Nanotubes with Supercritical Carbon Dioxide  

NASA Astrophysics Data System (ADS)

The properties of carbon nanotube (CNT)-polymer nanocomposites are far below than those calculated, mainly due to poor dispersion or interface quality. This is particularly difficult for single walled carbon nanotubes (SWNTs) as they tend to form bundles or ropes that are difficult to exfoliate. Supercritical fluid (SCF) assisted processing is one of the methods that can be used to exfoliate/disperse CNTs along with modifiying the interface of the CNTs. Molecular dynamics simulations were performed to understand how the surface modifiers behave near SWNT surface with and without the presence of SCF molecules. It is also important to understand the diffusivity of SCF molecules between SWNT bundles and the effect of surface modifiers on diffusion. Octane and n-perflourooctane molecules were used as surface modifiers with varying tethering density and carbon dioxide (CO2) was chosen as the SCF. Results showed that the system with highest number of n-perfluorooctanes presented the highest degree of success in separating the SWNTs in the presence of CO2.

Baysal, Nihat; Unsal, Banu; Ozisik, Rahmi

2006-03-01

337

Master/Diploma project Degradation of carbon dioxide by micro organisms  

E-print Network

microorganisms can use carbon dioxide as carbon source for their life cycle. Whereas plants are the main sourceMaster/Diploma project Degradation of carbon dioxide by micro organisms The accumulation of carbon of the carbon dioxide release is an important objective in the near future. Various strategies are discussed

Rostock, Universität

338

Influence of terrestrial inputs on continental shelf carbon dioxide  

NASA Astrophysics Data System (ADS)

The US South Atlantic Bight (SAB) is a low-latitude shallow continental shelf bordered landward by abundant salt marshes and rivers. Based on previously published data on sea surface partial pressure of carbon dioxide (pCO2) and new dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) data, a model analysis is presented to identify and quantify the contributions of various terrestrial carbon inputs on SAB sea surface pCO2. After removal of pCO2 variations due to annual temperature variability and air-sea gas exchange from the in situ pCO2, the temperature- and gas-exchange-corrected pCO2 (TG-corrected pCO2) is derived. Contributions from rivers, salt marshes, and the continental shelf to the TG-corrected pCO2 are then calculated. Our findings demonstrate that although additions of CO2 from within shelf waters (i.e., ?pCO2(shelf)) were the greatest of the three components and underwent the largest seasonal changes, ?pCO2(shelf) showed smaller onshore-offshore gradients than rivers and marshes. In contrast, CO2 contributions from river (?pCO2(river)) and salt marsh (?pCO2(marsh)) components were greatest closest to the coast and decreased with distance offshore. In addition, the magnitude of ?pCO2(marsh) was about three-fold greater than ?pCO2(river). Our findings also revealed that decomposition of terrestrial organic carbon was an important factor regulating the seasonal pattern of pCO2 on the inner shelf. Despite large uncertainties, this study demonstrates the importance of terrestrial inputs, in particular those from coastal wetlands, on coastal ocean CO2 distributions.

Jiang, L.-Q.; Cai, W.-J.; Wang, Y.; Bauer, J. E.

2013-02-01

339

Carbon dioxide and methane in karst systems Supervisors: Prof Dave Mattey, Dr Dave Lowry and Dr. Rebecca Fisher  

E-print Network

in environmental monitoring techniques in cave systems, stable isotope analysis of CO2 and CH4 in soil and cave air carbon isotopic evidence for oxidation of atmospheric methane in a dynamically ventilated caveCarbon dioxide and methane in karst systems Supervisors: Prof Dave Mattey, Dr Dave Lowry and Dr

Royal Holloway, University of London

340

Ionic Liquid Membranes for Carbon Dioxide Separation  

SciTech Connect

Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while with the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on amine interactions. The hypothesis is that the performance at the elevated temperatures could be improved by allowing a facilitated transport mechanism to become dominant. Several amine-based ionic liquids were tested on the cross-linked nylon support. It was found that using the amine-based ionic liquid did improve selectivity and permeability at higher temperature. The hypothesis was confirmed, and it was determined that the type of amine used also played a role in facilitated transport. Given the appropriate aminated ionic liquid with the cross-linked nylon support, it is possible to have a membrane capable of separating CO2 at IGCC conditions. With this being the case, the research has expanded to include separation of other constituents besides CO2 (CO, H2S, etc.) and if they play a role in membrane poisoning or degradation. This communication will discuss the operation of the recently fabricated ionic liquid membranes and the impact of gaseous components other than CO2 on their performance and stability.

Myers, C.R.; Ilconich, J.B.; Luebke, D.R.; Pennline, H.W.

2008-07-12

341

14 April 2001 tmospheric carbon dioxide  

E-print Network

emissions is through increased carbon sequestration into forests. In a large-scale assessment, Birdsey- ing carbon sequestration in southern forests. Carbon sequestration via southern pine forests may policy commitments. Keywords: carbon sequestration; southern pine forests ABSTRACT MEETING GLOBAL POLICY

Teskey, Robert O.

342

Urban Evapotranspiration and Carbon Dioxide Flux in Miami - Dade, Florida  

NASA Astrophysics Data System (ADS)

Atmospheric Carbon Dioxide (CO2) concentrations are leading indicators of secular climate change. With increasing awareness of the consequences of climate change, methods for monitoring this change are becoming more important daily. Of particular interest is the carbon dioxide exchange between natural and urban landscapes and the correlation of atmospheric CO2 concentrations. Monitoring Evapotranspiration (ET) is important for assessments of water availability for growing populations. ET is surprisingly understudied in the hydrologic cycle considering ET removes as much as 80 to over 100% of precipitation back into the atmosphere as water vapor. Lack of understanding in spatial and temporal ET estimates can limit the credibility of hydrologic water budgets designed to promote sustainable water use and resolve water-use conflicts. Eddy covariance (EC) methods are commonly used to estimate ET and CO2 fluxes. The EC platform consist of a (CSAT) 3-D Sonic Anemometer and a Li-Cor Open Path CO2/ H2O Analyzer. Measurements collected at 10 Hz create a very large data sets. A EC flux tower located in the Snapper Creek Well Field as part of a study to estimate ET for the Miami Dade County Water and Sewer project. Data has been collected from December 17, 2009 to August 30, 2010. QA/QC is performed with the EdiRe data processing software according to Ameri-flux protocols. ET estimates along with other data--latent-heat flux, sensible-heat flux, rainfall, air temperature, wind speed and direction, solar irradiance, net radiation, soil-heat flux and relative humidity--can be used to aid in the development of water management policies and regulations. Currently, many financial institutions have adopted an understanding about baseline environmental monitoring. The “Equator Principle” is an example of a voluntary standard for managing social and environmental risk in project financing and has changed the way in which projects are financed.

Bernier, T.; Hopper, W.

2010-12-01

343

The carbon dioxide challenge facing aviation  

NASA Astrophysics Data System (ADS)

This paper investigates the challenge that U.S. aviation would face in meeting future Greenhouse Gas (GHG) reduction goals to mitigate global climate change via technological options. This investigation is done within a framework that considers aviation GHG emissions as a function of aviation growth, aircraft efficiency, operational efficiency, and life cycle GHG emissions of aviation fuels. The concept of life cycle GHG intensity (LGI) with units of grams carbon dioxide equivalent per payload distance traveled is used for this purpose as it can be decomposed into components that quantify improvements in aircraft design, operations, and alternative fuels. For example, the life cycle GHG intensity of U.S. aviation in 2005 was 1.37 g CO2e/kg km. If U.S. aviation is to meet the IATA 2050 goal of a 50% reduction in CO2 relative to a 2005 baseline while allowing for a 3.2% annual growth rate in payload-distance traveled, it will need to decrease to 0.22 g CO2e/kg km in 2050, an 84% reduction. The analysis framework that is developed in this manuscript was used to compare the improvements in life cycle GHG intensity that could accompany the use of advanced aircraft designs, operational improvements, and alternative fuels to those required on a fleet-wide basis to meet the future GHG reduction goals under varied aviation growth scenarios. The results indicate that the narrow body segment of the fleet could indeed meet ambitious goals of reducing GHG emissions by 50%, relative to 2005 levels, with a 3.2% annual growth rate; however, it would require relatively rapid adoption of innovative aircraft designs and the widespread use of alternative fuels with relatively low life cycle GHG emissions.

Hileman, James I.; De la Rosa Blanco, Elena; Bonnefoy, Philippe A.; Carter, Nicholas A.

2013-11-01

344

Carbon dioxide exchange in a peatland ecosystem  

NASA Astrophysics Data System (ADS)

Micrometeorological measurements of carbon dioxide exchange were made in an open peatland in north central Minnesota during two growing seasons (1991 and 1992). The vegetation at the site was dominated by Sphagnum papillosum, Scheuchzeria palustris, and Chamaedaphne calyculata. The objective of the study was to examine the diurnal and seasonal variations in canopy photosynthesis (P) and develop information on the net ecosystem CO2 exchange. The two seasons provided contrasting microclimatic conditions: as compared with 1991, the 1992 season was significantly wetter and cooler. Canopy photosynthesis was sensitive to changes in light, temperature, and moisture stress (as indicated by water table depth and atmospheric vapor pressure deficit). Under moderate conditions (temperature 18-28°C, vapor pressure deficit 0.7-1.5 kPa, and water table near the surface) during the peak growth period, midday (averaged between 1000-1400 hours) P values ranged from 0.15 to 0.24 mg m-2 s-1. Under high-temperature (30°-34°C) and moisture stress (water table 0.16-0.23 m below the surface and vapor pressure deficit 2.2-3.0 kPa) conditions, midday P was reduced to about 0.03-0.06 mg m-2 s-1. There was a high degree of consistency in the values of P under similar conditions in the two seasons. Seasonally integrated values of the daily net ecosystem CO2 exchange indicated that the study site was a source of atmospheric CO2, releasing about 71 g C m-2 over a 145-day period (May-October) in 1991. Over a similar period in 1992, however, this ecosystem was a sink for atmospheric CO2 with a net accumulation of about 32 g C m-2. These results are consistent with previous investigations on CO2 exchange in other northern wetland sites during wet and dry periods.

Shurpali, N. J.; Verma, S. B.; Kim, J.; Arkebauer, T. J.

1995-07-01

345

Carbon Dioxide Carbonates in the Earth;s Mantle: Implications to the Deep Carbon Cycle  

SciTech Connect

An increase in the ionic character in C-O bonds at high pressures and temperatures is shown by the chemical/phase transformation diagram of CO{sub 2}. The presence of carbonate carbon dioxide (i-CO{sub 2}) near the Earth's core-mantle boundary condition provides insights into both the deep carbon cycle and the transport of atmospheric CO{sub 2} to anhydrous silicates in the mantle and iron core.

Yoo, Choong-Shik; Sengupta, Amartya; Kim, Minseob (Princeton); (WSU)

2012-05-22

346

Persistent local order heterogeneity in the supercritical carbon dioxide  

E-print Network

The supercritical state is currently viewed as uniform and homogeneous on the pressure-temperature phase diagram in terms of physical properties. Here, we study structural properties of the supercritical carbon dioxide, and discover the existence of persistent medium-range order correlations which make supercritical carbon dioxide non-uniform and heterogeneous on an intermediate length scale, a result not hitherto anticipated. We report on the carbon dioxide heterogeneity shell structure where, in the first shell, both carbon and oxygen atoms experience gas-like type inter- actions with short range order correlations, while within the second shell oxygen atoms essentially exhibit liquid-like type of interactions with medium range order correlations due to localisation of transverse-like phonon packets. We show that the local order heterogeneity remains in the three phase-like equilibrium within very wide temperature range. Importantly, we highlight a catalytic role of atoms inside the nearest neighbor heterogeneity shell in providing a mechanism for diffusion in the supercritical carbon dioxide on an intermediate length scale. Finally, we discuss important implications for answering the intriguing question whether Venus may have had carbon dioxide oceans and urge for an experimental detection of this persistent local order heterogeneity.

Dima Bolmatov; D. Zav'yalov; M. Gao; M. Zhernenkov

2014-06-06

347

Mar., 1955 GASIFICATIONOF CARBONRODSWITH CARBONDIOXIDE 241 GASIFICATION OF CARBON RODS WITH CARBON DIOXIDE1*2  

E-print Network

Mar., 1955 GASIFICATIONOF CARBONRODSWITH CARBONDIOXIDE 241 GASIFICATION OF CARBON RODS WITH CARBON commercial carbons and their gasification rates with carbon dioxide at a series of temperatures between 900. No general correlation between these properties and the carbon gasification rates was found. Introduction

348

Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide  

DOEpatents

A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

Rathke, J.W.; Klingler, R.J.

1993-03-30

349

Capturing carbon dioxide as a polymer from natural gas  

NASA Astrophysics Data System (ADS)

Natural gas is considered the cleanest and recently the most abundant fossil fuel source, yet when it is extracted from wells, it often contains 10-20?mol% carbon dioxide (20-40?wt%), which is generally vented to the atmosphere. Efforts are underway to contain this carbon dioxide at the well-head using inexpensive and non-corrosive methods. Here we report nucleophilic porous carbons are synthesized from simple and inexpensive carbon-sulphur and carbon-nitrogen precursors. Infrared, Raman and 13C nuclear magnetic resonance signatures substantiate carbon dioxide fixation by polymerization in the carbon channels to form poly(CO2) under much lower pressures than previously required. This growing chemisorbed sulphur- or nitrogen-atom-initiated poly(CO2) chain further displaces physisorbed hydrocarbon, providing a continuous carbon dioxide selectivity. Once returned to ambient conditions, the poly(CO2) spontaneously depolymerizes, leading to a sorbent that can be easily regenerated without the thermal energy input that is required for traditional sorbents.

Hwang, Chih-Chau; Tour, Josiah J.; Kittrell, Carter; Espinal, Laura; Alemany, Lawrence B.; Tour, James M.

2014-06-01

350

Capturing carbon dioxide as a polymer from natural gas.  

PubMed

Natural gas is considered the cleanest and recently the most abundant fossil fuel source, yet when it is extracted from wells, it often contains 10-20 mol% carbon dioxide (20-40 wt%), which is generally vented to the atmosphere. Efforts are underway to contain this carbon dioxide at the well-head using inexpensive and non-corrosive methods. Here we report nucleophilic porous carbons are synthesized from simple and inexpensive carbon-sulphur and carbon-nitrogen precursors. Infrared, Raman and (13)C nuclear magnetic resonance signatures substantiate carbon dioxide fixation by polymerization in the carbon channels to form poly(CO2) under much lower pressures than previously required. This growing chemisorbed sulphur- or nitrogen-atom-initiated poly(CO2) chain further displaces physisorbed hydrocarbon, providing a continuous carbon dioxide selectivity. Once returned to ambient conditions, the poly(CO2) spontaneously depolymerizes, leading to a sorbent that can be easily regenerated without the thermal energy input that is required for traditional sorbents. PMID:24892923

Hwang, Chih-Chau; Tour, Josiah J; Kittrell, Carter; Espinal, Laura; Alemany, Lawrence B; Tour, James M

2014-01-01

351

Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis  

E-print Network

Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis by electrostatic forces, despite the ultralow dielectric constant of 1.5. Zeta potentials of micrometer- sized a dozen droplets with lengths of 50 m. The ability to form electrostatically stabilized colloids in carbon

352

Distribution of and changes in industrial carbon dioxide production  

Microsoft Academic Search

The burning of fossils fuels is believed to be the major source responsible for an observed increase in the concentration of carbon dioxide in the atmosphere now measured at many locations around the world. This paper revises earlier published data on the annual amounts of carbon released to the atmosphere during the period 1950--1978 and updates the record through 1980.

Ralph M. Rotty

1983-01-01

353

II. Greenhouse gas markets, carbon dioxide credits and biofuels17  

E-print Network

15 II. Greenhouse gas markets, carbon dioxide credits and biofuels17 The previous chapter analysed biofuels production. GHG policies18 that create a carbon price either through an emissions trading system or directly by taxing GHG emissions also generate increased demand for biofuels. They do so by raising

354

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

The objective of this project is to develop a simple and inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests suggested that higher temperature calcination of trona leds to reduced carbonation activity in subsequent cycles, but that calcination in dry carbon dioxide did not result in decreased activity relative to calcination in helium. Following higher temperature calcination, sodium bicarbonate (SBC) No.3 has greater activity than either coarse or fine grades of trona. Fixed bed testing of calcined SBC No.3 at 70 C confirmed that high rates of carbon dioxide absorption are possible and that the resulting product is a mixture of Wegscheider's salt and sodium carbonate. In fluidized bed testing of supported potassium carbonate, very rapid carbonation rates were observed. Activity of the support material complicated the data analysis. A milled, spherical grade of SBC appeared to be similar in attrition and abrasion characteristics to an unmilled, less regularly shaped SBC. The calcination behavior, at 107 C, for the milled and unmilled materials was also similar.

David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P.Gupta; William J. McMichael; Ya Liang; Douglas P. Harrison

2002-10-01

355

Carbon Dioxide Effects Research and Assessment Program. Carbon Dioxide Research Progress Report, fiscal year 1979  

SciTech Connect

Research on the global carbon cycle and the effects of increased carbon dioxide on the global climate system is reported. Environmental and societal effects related to CO/sub 2/ and environmental control technology for CO/sub 2/ are also discussed. Lists of research projects and reports and publications of the Carbon Dioxide and Climate Research Program are included. An expanded CO/sub 2/ monitoring network is providing increased coverage for interpretation of patterns of sources and sinks seasonal variability, and documentation of the global growth of CO/sub 2/. Modeling studies emphasized that knowledge of the transport and mixing of surface ocean waters is important in understanding deep oceanic circulation. Initial studies in the equatorial Pacific are helping quantify estimates of the amount of outgassing CO/sub 2/ from tropical waters. During fiscal year 1979, there was a substantial increase in appreciation of the role of the ocean in controlling not only atmospheric CO/sub 2/ concentrations but also the climatic response to changes in concentration. Model simulations of the effect of doubled CO/sub 2/ concentration carried out with fixed ocean temperatures a situation that is possible during perhaps the next 20 years, showed relatively small summer heating over land areas. On the other hand, simulations in which the oceanic temperatures could come into instantaneous equilibrium with atmospheric conditions continued to show global temperature increases of 3 +- 1.5/sup 0/C, accentuated at high latitudes. To improve understanding of possible regional climate changes, there were increased efforts to reconstruct regional climatic patterns prevailing during past warm periods that might serve as analogs of future climatic conditions. Particular attention was directed to the climates of the United States and other countries bordering the North Atlantic Ocean during the warm period 5000 to 7000 years ago.

Dahlman, R.C.; Gross, T.; Machta, L.; Elliott, W.; MacCracken, M.

1980-04-01

356

Persistent local order heterogeneity in the supercritical carbon dioxide  

E-print Network

The supercritical state is currently viewed as uniform and homogeneous on the pressure-temperature phase diagram in terms of physical properties. Here, we study structural properties of the supercritical carbon dioxide, and discover the existence of persistent medium-range order correlations which make supercritical carbon dioxide non-uniform and heterogeneous on an intermediate length scale, a result not hitherto anticipated. We report on the carbon dioxide heterogeneity shell structure where, in the first shell, both carbon and oxygen atoms experience gas-like type inter- actions with short range order correlations, while within the second shell oxygen atoms essentially exhibit liquid-like type of interactions with medium range order correlations due to localisation of transverse-like phonon packets. We show that the local order heterogeneity remains in the three phase-like equilibrium within very wide temperature range. Importantly, we highlight a catalytic role of atoms inside the nearest neighbor heterog...

Bolmatov, Dima; Gao, M; Zhernenkov, M

2014-01-01

357

Carbon dioxide effects on crop energy balance: Testing ecosys with a free-air CO{sub 2} enrichment (FACE) experiment  

SciTech Connect

Elevated CO{sub 2} concentrations (C{sub e}) have been observed to decrease short-term plant water use under controlled conditions by increasing stomatal resistance. The extent to which this decrease occurs over a growing season in the field is uncertain, however, because stomatal resistance is only one of many mechanisms that control water use. In this study, we tested the ecosystem simulation model ecosys, which reproduces an hourly energy balance through soil-vegetation systems under defined atmospheric boundary conditions, using energy exchange data measured as part of the Free-Air CO{sub 2} Enrichment (FACE) experiment at C{sub e}=550 vs. 370 {mu}mol mol{sup -1}. The model reproduced reductions in measured upward latent heat fluxes that varied from -10 to +40 W m{sup -2}, depending on atmospheric conditions. In the model, the primary effect of elevated C{sub e} on latent heat fluxes was through canopy stomatal conductance. This effect was largely offset by secondary effects through canopy temperature that enabled the model to reproduce measured changes in sensible heat fluxes. The total effect simulated by ecosys of C{sub e}=550 vs. 370 {mu}mol mol{sup -1} on evapotranspiration during the entire FACE experiment was a reduction of 7%. This reduction compares with one of 11% estimated from accumulated daily measurements of latent heat flux. In the model, the different effects of C{sub e} on plant water use depend on atmosphere and soil boundary conditions, and are highly dynamic. Consequently the simulated C{sub e}-water use relationship is likely to be site-specific. The use of models such as ecosys allows site-specific boundary conditions to be considered in the study of C{sub e} effects on plant growth and water use. 51 refs., 7 figs., 2 tabs.

Grant, R.F. [Univ. of Alberta, Edmonton (Canada); Kimball, B.A.; Pinter, P.J. [Water Conservation Lab., Phoenix, AZ (United States)

1995-05-01

358

Carbon dioxide consumption during soil development  

Microsoft Academic Search

Carbon is sequestered in soils by accumulation of recalcitrant organic matter and by bicarbonate weathering of silicate minerals. Carbon fixation by ecosystems helps drive weathering processes in soils and that in turn diverts carbon from annual photosynthesis-soil respiration cycling into the long-term geological carbon cycle. To quantify rates of carbon transfer during soil development in moist temperate grassland and desert

Oliver A. Chadwick; Eugene F. Kelly; Dorothy M. Merritts; Ronald G. Amundson

1994-01-01

359

Modeling the diffusion effects through the iron carbonate layer in the carbon dioxide corrosion of carbon steel  

SciTech Connect

A mechanistic model was developed for predicting carbon dioxide corrosion rates of carbon steel pipes in multiphase flow conditions. The model incorporates the chemistry, thermodynamics of carbon dioxide dissolution, multiphase mass transfer, electrochemical kinetics on the metal surface and the presence of a corrosion product film. The predicted corrosion rates show good agreement with the experimental results.

Rajappa, S.; Zhang, R.; Gopal, M. [Ohio Univ., Athens, OH (United States)

1998-12-31

360

Predator-induced reduction of freshwater carbon dioxide emissions  

NASA Astrophysics Data System (ADS)

Predators can influence the exchange of carbon dioxide between ecosystems and the atmosphere by altering ecosystem processes such as decomposition and primary production, according to food web theory. Empirical knowledge of such an effect in freshwater systems is limited, but it has been suggested that predators in odd-numbered food chains suppress freshwater carbon dioxide emissions, and predators in even-numbered food chains enhance emissions. Here, we report experiments in three-tier food chains in experimental ponds, streams and bromeliads in Canada and Costa Rica in the presence or absence of fish (Gasterosteus aculeatus) and invertebrate (Hesperoperla pacifica and Mecistogaster modesta) predators. We monitored carbon dioxide fluxes along with prey and primary producer biomass. We found substantially reduced carbon dioxide emissions in the presence of predators in all systems, despite differences in predator type, hydrology, climatic region, ecological zone and level of in situ primary production. We also observed lower amounts of prey biomass and higher amounts of algal and detrital biomass in the presence of predators. We conclude that predators have the potential to markedly influence carbon dioxide dynamics in freshwater systems.

Atwood, Trisha B.; Hammill, Edd; Greig, Hamish S.; Kratina, Pavel; Shurin, Jonathan B.; Srivastava, Diane S.; Richardson, John S.

2013-03-01

361

Membrane processes for gas separations: Part I. Removal of carbon dioxide and hydrogen sulfide from low-quality natural gas. Part II. Enrichment of krypton in air  

NASA Astrophysics Data System (ADS)

I. The objective of this study was to determine the process design characteristics and economics of membrane separation processes for reducing the concentrations of H2S and CO2 in low-quality natural gas containing substantial amounts of the two acid gases to pipeline specifications ( ? 2 mole-% CO2 and ? 4 ppm H2S). The new processes considered the simultaneous use of two different types of polymer membranes for the above application, namely, one with higher CO2/CH4 selectivity and the other with higher H2S/CH4 selectivity. The performance and economics of membrane process configurations comprising one, two, and three permeation stages, with and without recycle streams, were examined and optimized via extensive computer simulations. Most computations assumed as a "base-case", the processing of a medium-size natural gas stream of 35 MMSCFD at 800 psia. The natural gas was taken to contain ? 10 mole-% H2S and ? 40 mole-% CO2. The most economical process configuration was two permeation stages in series, with H2S-selective membranes in the first stage and CO2-selective membranes in the second stage. The most economical process configurations for upgrading natural gas containing either only substantial amounts of H2S or of CO2 were also determined. The sensitivity of the process economics to feed flow rate, feed pressure, membrane module cost, and wellhead cost of natural gas was studied. A comparison of the processing cost of membrane processes with that of conventional gas absorption processes utilizing diethanolamine as solvent was also investigated. II. A membrane process for enrichment of Kr in air was studied experimentally as a technique of improving the accuracy of Kr analysis. "Asymmetric" silicone rubber membranes were found to be most suitable for this application. The study was investigated with a feed gas mixture containing 0.99 mole-% Kr, 20.70 mole-% O2, and 78.30 mole-% N2. The Kr concentration could be increased from 0.99 to 2.23 mole-% in a single membrane stage and further raised to 3.73 mole-% in two stages in cascade. Computer simulations of "cross-flow" model yielded results in general agreement with experimental data.

Hao, Jibin

1998-12-01

362

New passive colorimetric air monitoring badge system for ammonia, sulfur dioxide, and nitrogen dioxide  

SciTech Connect

A new passive colorimetric air monitoring badge system was developed to determine the time-weighted average (TWA) concentration of specific inorganic vapor contaminants in air. The system consists of a small passive badge which either can be worn by employees for personal monitoring or used as an area monitor and a portable colorimetric readout instrument which determines the exposure dose in ppM-hours. To date, systems have been developed for ammonia, sulfur dioxide, and nitrogen dioxide, and they will meet or exceed both NIOSH and OSHA accuracy requirements. The overall performance of these systems, based on laboratory tests designed to show overall accuracy, linearity, and environmental effects, is described. Field test results are also presented.

Kring, E.V.; Lautenberger, W.J.; Baker, W.B.; Douglas, J.J.; Hoffman, R.A.

1981-05-01

363

SCORR - supercritical carbon dioxide resist removal.  

SciTech Connect

SCORR, short for supercritical carbon dioxide resist removal, is a new technology that could continue to enable the technological development of photolithography processes in industry. SCORR is based upon the physical properties of supercritical fluids (SCFs). These special properties enable SCFs to remove coatings, residues, and particles froin high-aspect-ratio structures in integrated circuits (ICs). SCORR also eliminates rinsing and drying steps presently used in IC manufacture, thereby eliminating the generation of millions of gallons of water per fab per day. Fabricating integrated circuits relies heavily on photolithography to define the shape and pattern of individual components. Once a single stage of a silicon wafer's topography has been completed, the hardened resist must be removed. Conventional processes generates more waste than any single step in the IC manufacturing process, and the production of a complete IC can involve many photolithography iterations. The cost associated with the treatment and disposal of this waste, as well as employee health and safety considerations, are driving a search for a1 ternative, environmentally benign, cost-effective solutions. In addition, photoresist stripping is confronting finer architectures and higher aspect ratios, as well as new low-k materials that are highly sensitive to post-etch residue. Low-k dielectrics and low-resistivity conductors such as copper are necessary for meeting industry's need for faster and smaller chips. Further, each low-k choice requires different plasma-etching processes, or chemistries, to etch structures into the low-k material; therefore, the nature of the residues can be different. No one product can meet all copper/low-k applications, and existing chemistries are not tunable - or even desirable - for the new processes. We have developed a new process - known as SCORR - that removes photoresist and post-ash, -etch, and -CMP (particulate) residue from semiconductor wafers. As IC feature sizes become smaller, the need for ensuring particle removal will increase. With feature sizes of less than 0.18{micro}m, it will become imperative that all particles greater than about 0.1 micron be removed from the semiconductor wafer. Existing cleaning technologies (such as liquid or high-pressure jet scrubbing) cannot remove particles on the order of 0.1 micron because of surface boundary layer constraints. Because of the low viscosities of supercritical fluids (SCFs), these constraints are virtually eliminated.

Jacobson, G. B. (Gunilla B.); Williams, L. L. (Laurie L.); Hollis, W. K. (William K.); Barton, Jerome C.; Taylor, C. M. (Craig M.)

2002-01-01

364

Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.  

PubMed

Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role. PMID:22859266

Tsuji, Yasushi; Fujihara, Tetsuaki

2012-10-14

365

Water and Carbon Dioxide Adsorption at Olivine Surfaces  

SciTech Connect

Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbon dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.

Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

2013-11-14

366

Carbon Dioxide Sequestration with Flue Gas Desulfurization (FGD) Gypsum  

Microsoft Academic Search

Carbonation of industrial alkaline residues can be used as a CO2 sequestration technology to reduce carbon dioxide emissions. In this study, alkaline Ca-rich flue gas desulfurization (FGD) gypsum samples were carbonated to a varying extent. These materials are cheap, available near large point sources of CO2 (power plant), and tend to react relatively rapidly with CO2 due to their chemical

Hongqi Wang; Ningning Sun; Rona J. Donahoe

2009-01-01

367

Carbonic Acid as a Reserve of Carbon Dioxide on Icy Moons: The Formation of Carbon Dioxide (CO2) in a Polar Environment  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ?3 band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO2 band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H2O)-carbon dioxide (CO2) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ?3 band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

2014-06-01

368

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates, through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests conducted at LSU indicated that exposure of sorbent to water vapor prior to contact with carbonation gas does not significantly increase the reaction rate. Calcined fine mesh trona has a greater initial carbonation rate than calcined sodium bicarbonate, but appears to be more susceptible to loss of reactivity under severe calcination conditions. The Davison attrition indices for Grade 5 sodium bicarbonate, commercial grade sodium carbonate and extra fine granular potassium carbonate were, as tested, outside of the range suitable for entrained bed reactor testing. Fluidized bed testing at RTI indicated that in the initial stages of reaction potassium carbonate removed 35% of the carbon dioxide in simulated flue gas, and is reactive at higher temperatures than sodium carbonate. Removals declined to 6% when 54% of the capacity of the sorbent was exhausted. Carbonation data from electrobalance testing was correlated using a shrinking core reaction model. The activation energy of the reaction of sodium carbonate with carbon dioxide and water vapor was determined from nonisothermal thermogravimetry.

David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

2002-04-01

369

Helium enrichment during convective carbon dioxide dissolution  

NASA Astrophysics Data System (ADS)

Motivated by observed variations of the CO2/He ratios in natural carbon dioxide (CO2) reservoirs, such as the Bravo Dome field in northeastern New Mexico, we have performed laboratory experiments equilibrating gas mixtures containing Helium (He) and CO2 with water, at close to ambient conditions in a closed system. The experimental design allows for continuous measurement of headspace pressure as well as timed interval measurements of the CO2/He ratios and the ?13C value of CO2 in the headspace. Results from three dissolution experiments are reported: 1) pure Helium system, 2) 98% CO2 + 2% Nitrogen system, and 3) 97% CO2 and 3% Helium. Final equilibrated experimental results are compared to theoretical results obtained using Henry's Law relationships. The evolution of the amount of dissolved CO2 computed from gas pressure and gas compositions are in good agreement with Henry's Law relationships. For example, the CO2 + N2 system was initially pressurized with pure CO2 to 1323 mbar and after six days it equilibrated to a measured headspace pressure of 596 mbar. This compares very well with a calculated equilibrium headspace pressure of 592 mbar for this system. The CO2 + He system was pressurized to 1398 mbar CO2 and after six days equilibrated to a measured headspace pressure of 397 mbar. This measured pressure is slightly higher than the predicted equilibrated headspace pressure of 341 mbar, indicating a possible leak in the system during this particular experiment. In both experiments the initial pH of the water was 9.3 and the final equilibrated pH was 5.4. The ?13C value of equilibrated headspace CO2 was within 0.25‰ of its starting ?13C value, demonstrating insignificant carbon isotope fractionation at low pH. Measured Helium/ CO2 ratios throughout the CO2+Helium experiment preserve a non-linear trend of increasing He/ CO2 ratios through time that correlate very well with the measured pressure drop from CO2 dissolution. This indicates that gas composition, in particular the He/ CO2-ratio, can be used to infer the amount of dissolved CO2 in the field where pressure evolution is not available. Our experiments show that the rate of dissolution is determined by convective mass transfer in the brine. Convective transport is driven by the increase of water density with increasing CO2 saturation. However, unlike previous experiments with analog systems we do not observe a constant dissolution rate. This is due to the continued drop in gas pressure that continuously reduces the equilibrium aqueous CO2 concentration and with it the driving force for convection. This feed back may significantly reduce the magnitude of solubility trapping that can be expected during geological CO2 storage.

Larson, T.; Hesse, M. A.

2013-12-01

370

Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents  

SciTech Connect

This report describes research conducted between July 1, 2006 and September 30, 2006 on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from coal combustion flue gas. Modifications to the integrated absorber/ sorbent regenerator/ sorbent cooler system were made to improve sorbent flow consistency and measurement reliability. Operation of the screw conveyor regenerator to achieve a sorbent temperature of at least 120 C at the regenerator outlet is necessary for satisfactory carbon dioxide capture efficiencies in succeeding absorption cycles. Carbon dioxide capture economics in new power plants can be improved by incorporating increased capacity boilers, efficient flue gas desulfurization systems and provisions for withdrawal of sorbent regeneration steam in the design.

David A. Green; Thomas O. Nelson; Brian S. Turk; Paul D. Box Raghubir P. Gupta

2006-09-30

371

CARBON DIOXIDE SEPARATION BY PHASE ENHANCED GAS-LIQUID ABSORPTION  

SciTech Connect

A new process called phase enhanced gas-liquid absorption has been developed in its early stage. It was found that adding another phase into the absorption system of gas/aqueous phase could enhance the absorption rate. A system with three phases was studied. In the system, gas phase was carbon dioxide. Two liquid phases were used. One was organic phase. Another was aqueous phase. By addition of organic phase into the absorption system of CO{sub 2}-aqueous phase, the absorption rate of CO{sub 2} was increased significantly. CO{sub 2} finally accumulated into aqueous phase. The experimental results proved that (1) Absorption rate of carbon dioxide was enhanced by adding organic phase into gas aqueous phase system; (2) Organic phase played the role of transportation of gas solute (CO{sub 2}). Carbon dioxide finally accumulated into aqueous phase.

Liang Hu

2004-09-30

372

CARBON DIOXIDE SEPARATION BY PHASE ENHANCED GAS-LIQUID ABSORPTION  

SciTech Connect

A new process called phase enhanced gas-liquid absorption has been developed in its early stage. It was found that adding another phase into the absorption system of gas/aqueous phase could enhance the absorption rate. A system with three phases was studied. In the system, gas phase was carbon dioxide. Two liquid phases were used. One was organic phase. Another was aqueous phase. By addition of organic phase into the absorption system of CO{sub 2}-aqueous phase, the absorption rate of CO{sub 2} was increased significantly. CO{sub 2} finally accumulated into aqueous phase. The experimental results proved that (1) Absorption rate of carbon dioxide was enhanced by adding organic phase into gas aqueous phase system; (2) Organic phase played the role of transportation of gas solute (CO{sub 2}). Carbon dioxide finally accumulated into aqueous phase.

Liang Hu; Adeyinka A. Adeyiga

2004-05-01

373

[Thoracoscopic thymectomy with carbon dioxide insufflation in the mediastinum].  

PubMed

The case is presented of a 71 year-old male, diagnosed with a thymoma. A thoracoscopic thymectomy was performed using the carbon dioxide insufflation technique in the mediastinum. During the procedure, while performing one-lung ventilation, the patient's respiration worsened. The contralateral lung had collapsed, as carbon dioxide was travelling from the mediastinum to the thorax through the opened pleura. Two-lung ventilation was decided upon, which clearly improved oxygenation in the arterial gases and airway pressures. Both pH and pCO2 stabilized. The surgical approach and the carbon dioxide technique were continued because 2-lung ventilation did not affect the surgical procedure. This technique has many serious complications and it should always be performed using 2-lung ventilation. PMID:24952826

Ferrero-Coloma, C; Navarro-Martinez, J; Bolufer, S; Rivera-Cogollos, M J; Alonso-García, F J; Tarí-Bas, M I

2015-02-01

374

BOREAS TGB-12 Isotropic Carbon Dioxide Data over the NSA  

NASA Technical Reports Server (NTRS)

The BOREAS TGB-12 team made measurements of soil carbon inventories, carbon concentration in soil gases, and rates of soil respiration at several sites to estimate the rates of carbon accumulation and turnover in each of the major vegetation types. This data set contains information on the carbon isotopic content of carbon dioxide sampled from soils in the NSA-OBS, NSA-YJP, and NSA-OJP sites. Data were collected from 14-Nov-1993 to 10-Oct-1996. The data are stored in tabular ASCII files.

Trumbore, Susan; Hall, Forrest G. (Editor); Sundquist, Eric; Winston, Greg; Conrad, Sara K. (Editor)

2000-01-01

375

Double-blind acute clonazepam vs. placebo in carbon dioxide-induced panic attacks.  

PubMed

The inhalation of 35% carbon dioxide has consistently been shown to provoke panic attacks in panic disorder patients. We aim to determine if an acute dose of clonazepam (2 mg) attenuates the panic attacks induced by an inhalation of 35% carbon dioxide in panic disorder. Twenty-two panic disorder patients who had been drug-free for 1 week participated in a carbon dioxide challenge test 1 h after a dose of either 2 mg of clonazepam or placebo with a randomized double-blind method. Also in a double-blind design during the tests the patients inhaled either atmospheric compressed air ('placebo control') or the carbon dioxide mixture. All patients participated in both tests which were done with a 20-min interval. Immediately before and after the inhalation, the anxiety levels and the symptoms of panic were always assessed. In the clonazepam group (n=11) two patients (18.2%) had a mild panic attack and in the placebo group (n=11) nine patients (81.8%) had a moderate to severe panic attack in the CO(2) challenge test. No patient had panic attacks during inhalation of atmospheric compressed air although anticipatory anxiety levels tended to be higher than in the CO(2) tests. After the CO(2) test anxiety levels were significantly greater in the CO(2) group (three-way ANOVA with Geisser-Greenhouse adjustments, F(31.92,1.86)=17.15, d.f.=7, P=0.013). Although a small sample was studied, the findings suggest the efficacy of an acute dose of clonazepam in attenuating panic attacks induced by carbon dioxide inhalation. PMID:10808043

Nardi, A E; Valença, A M; Nascimento, I; Mezzasalma, M A; Zin, W A

2000-05-15

376

49 CFR 195.8 - Transportation of hazardous liquid or carbon dioxide in pipelines constructed with other than...  

Code of Federal Regulations, 2014 CFR

... Transportation of hazardous liquid or carbon dioxide in pipelines constructed with... Transportation of hazardous liquid or carbon dioxide in pipelines constructed with...person may transport any hazardous liquid or carbon dioxide through a pipe that is...

2014-10-01

377

Regulation of Carbonic Anhydrase Expression by Zinc, Cobalt, and Carbon Dioxide in the Marine Diatom  

E-print Network

Regulation of Carbonic Anhydrase Expression by Zinc, Cobalt, and Carbon Dioxide in the Marine of carbonic anhydrase (CA) in the marine diatom Thalassiosira weissflogii. We have examined the roles components: a mechanism for directly or indirectly taking up HCO3 and at least one carbonic anhydrase (CA

Morel, François M. M.

378

Entrapment of Carbon Dioxide in the Active Site of Carbonic Anhydrase II*  

E-print Network

Entrapment of Carbon Dioxide in the Active Site of Carbonic Anhydrase II* Received for publication step of CO2 hydration catalyzed by the zinc- metalloenzyme human carbonic anhydrase II, the binding substrates and revealing hydrophobic pockets in proteins. Since their discovery (2), the carbonic anhydrases

Gruner, Sol M.

379

Fate of fossil fuel carbon dioxide and the global carbon budget  

Microsoft Academic Search

The fate of fossil fuel carbon dioxide released into the atmosphere depends on the exchange rates of carbon between the atmosphere and three major carbon reservoirs, namely, the oceans, shallow-water sediments, and the terrestrial biosphere. Various assumptions and models used to estimate the global carbon budget for the last 20 years are reviewed and evaluated. Several versions of recent atmosphere-ocean

W. S. Broecker; T. Takahashi; H. J. Simpson; T.-H. Peng

1979-01-01

380

Carbon dioxide and methane emissions from the Yukon River system  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) and methane (CH4) emissions are important, but poorly quantified, components of riverine carbon (C) budgets. This is largely because the data needed for gas flux calculations are sparse and are spatially and temporally variable. Additionally, the importance of C gas emissions relative to lateral C exports is not well known because gaseous and aqueous fluxes are not commonly measured on the same rivers. We couple measurements of aqueous CO2 and CH4 partial pressures (pCO2, pCH4) and flux across the water-air interface with gas transfer models to calculate subbasin distributions of gas flux density. We then combine those flux densities with remote and direct observations of stream and river water surface area and ice duration, to calculate C gas emissions from flowing waters throughout the Yukon River basin. CO2 emissions were 7.68 Tg C yr-1 (95% CI: 5.84 -10.46), averaging 750 g C m-2 yr-1 normalized to water surface area, and 9.0 g C m-2 yr-1 normalized to river basin area. River CH4 emissions totaled 55 Gg C yr-1 or 0.7% of the total mass of C emitted as CO2 plus CH4 and ˜6.4% of their combined radiative forcing. When combined with lateral inorganic plus organic C exports to below head of tide, C gas emissions comprised 50% of total C exported by the Yukon River and its tributaries. River CO2 and CH4 derive from multiple sources, including groundwater, surface water runoff, carbonate equilibrium reactions, and benthic and water column microbial processing of organic C. The exact role of each of these processes is not yet quantified in the overall river C budget.

Striegl, Robert G.; Dornblaser, M. M.; McDonald, C. P.; Rover, J. R.; Stets, E. G.

2012-12-01

381

Quantum cascade laser based spectrometer for in situ stable carbon dioxide isotope measurements  

Microsoft Academic Search

Simultaneous concentration measurements of the three main stable carbon dioxide isotopologues (16O12C16O, 16O13C16O and 18O12C16O) in ambient air are demonstrated. The instrument employs a quasi-room temperature, pulsed quantum cascade laser emitting at 4.3?m. Both the laser and the IR detector are thermoelectrically cooled, which greatly facilitates cryogenic-free, continuous operation. The Allan plot of the time series of the retrieved spectroscopic

B. Tuzson; M. J. Zeeman; M. S. Zahniser; L. Emmenegger

2008-01-01

382

CORA – a dedicated device for carbon dioxide monitoring in cave environments  

Microsoft Academic Search

High resolution time-series of cave CO2 fluctuations are increasingly demanded to quantify calcite precipitation processes. CORA, an energy-efficient NDIR-device, has been specifically developed for the long-term monitoring of carbon dioxide in remote cave environments. To allow comparison between different cave sites, changes in air pressure and temperature are compensated for using dedicated probes. Laboratory experiments demonstrate that CORA’s precision is

Marc Luetscher; Felix Ziegler

2012-01-01

383

COCAP - A compact carbon dioxide analyser for airborne platforms  

NASA Astrophysics Data System (ADS)

Airborne platforms are a valuable tool for atmospheric trace gas measurements due to their capability of movement in three dimensions, covering spatial scales from metres to thousands of kilometres. Although crewed research aircraft are flexible in payload and range, their use is limited by high initial and operating costs. Small unmanned aerial vehicles (UAV) have the potential for substantial cost reduction, but require lightweight, miniaturized and energy-efficient scientific equipment. We are developing a COmpact Carbon dioxide analyser for Airborne Platforms (COCAP). It contains a non-dispersive infrared CO2sensor with a nominal full scale of 3000 ?mol/mol. Sampled air is dried with magnesium perchlorate before it enters the sensor. This enables measurement of the dry air mole fraction of CO2, as recommended by the World Meteorological Organization. During post-processing, the CO2 measurement is corrected for temperature and pressure variations in the gas line. Allan variance analysis shows that we achieve a precision of better than 0.4 ?mol/mol for 10 s averaging time. We plan to monitor the analyser's stability during flight by measuring reference air from a miniature gas tank in regular intervals. Besides CO2, COCAP measures relative humidity, temperature and pressure of ambient air. An on-board GPS receiver delivers accurate timestamps and allows georeferencing. Data is both stored on a microSD card and simultaneously transferred over a wireless serial interface to a ground station for real-time review. The target weight for COCAP is less than 1 kg. We deploy COCAP on a commercially available fixed-wing UAV (Bormatec Explorer) with a wingspan of 2.2 metres. The UAV has high payload capacity (2.5 kg) as well as sufficient space in the fuselage (80x80x600 mm3). It is built from a shock-resistant foam material, which allows quick repair of minor damages in the field. In case of severe damage spare parts are readily available. Calculations suggest that the UAV can reach a maximum altitude of 2000 metres. COCAP will aid in interpreting ground-based trace gas measurements by profiling the lower troposphere. In addition, transport modelling around measurement sites can be improved by assimilating the profiles-derived mixed layer height. Furthermore, COCAP is a promising tool for the identification of CO2 point sources, e.g. leaking carbon storage sites.

Kunz, Martin; Lavri?, Jošt V.; Jeschag, Wieland; Bryzgalov, Maksym; Hök, Bertil; Heimann, Martin

2014-05-01

384

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2010 CFR

...National secondary ambient air quality standard for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.5 National secondary ambient air quality standard for sulfur oxides (sulfur...

2010-07-01

385

40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...National secondary ambient air quality standard for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.5 National secondary ambient air quality standard for sulfur oxides (sulfur...

2011-07-01

386

40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).  

Code of Federal Regulations, 2011 CFR

...National primary ambient air quality standards for sulfur oxides (sulfur dioxide...PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS § 50.17 National primary ambient air quality standards for sulfur oxides (sulfur...

2011-07-01

387

Classroom Demonstration: Combustion of Diamond to Carbon Dioxide Followed by Reduction to Graphite  

ERIC Educational Resources Information Center

An educational demonstration shows the combustion of carbon to carbon dioxide and then the reduction of carbon dioxide to carbon. A melee diamond is the source of the carbon and the reaction is carried out in a closed flask. The demonstration helps students to realize that diamonds are made of carbon and that atoms do not change or vanish in…

Miyauchi, Takuya; Kamata, Masahiro

2012-01-01

388

Predicted shift in the C-13/C-12 ratio of atmospheric carbon dioxide  

NASA Astrophysics Data System (ADS)

Knowledge of recent global changes in the rare isotopic species (C-13)O2 in atmospheric carbon dioxide does not now distinguish whether the land biosphere is a source or sink for fossil fuel carbon dioxide. The question is critically dependent on isotopic fractionation between the atmosphere and ocean water; if the isotopic fractionation factor for CO2 uptake at the air-ocean boundary, alpha(am), is approximately 0.986, as is the case for strongly alkaline solutions, the (C-13)O2 content of atmospheric CO2 is insensitive to changes in the biosphere; if alpha(am) is approximately unity, as now seems likely for ocean water, very accurate measurements, over the next decade or longer, will permit an estimation to be made of the net global loss or gain of biospheric carbon.

Keeling, C. D.; Bacastow, R. B.; Tans, P. P.

1980-07-01

389

Carbon Dioxide Capture from Coal-Fired Power Plants: A Real Options Analysis Ram Chandra Sekar  

E-print Network

Carbon Dioxide Capture from Coal-Fired Power Plants: A Real Options Analysis by Ram Chandra Sekar;2 #12;3 Carbon Dioxide Capture in Coal-Fired Power Plants: A Real Options Analysis by Ram Chandra Sekar

390

Carbon dioxide sequestration by aqueous mineral carbonation of magnesium silicate minerals  

SciTech Connect

The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has caused concerns about global warming. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of carbon dioxide. Increased efficiency of these power plants will have a large impact on carbon dioxide emissions, but additional measures will be needed to slow or stop the projected increase in the concentration of atmospheric carbon dioxide. By accelerating the naturally occurring carbonation of magnesium silicate minerals it is possible to sequester carbon dioxide in the geologically stable mineral magnesite (MgCO3). The carbonation of two classes of magnesium silicate minerals, olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4), was investigated in an aqueous process. The slow natural geologic process that converts both of these minerals to magnesite can be accelerated by increasing the surface area, increasing the activity of carbon dioxide in the solution, introducing imperfections into the crystal lattice by high-energy attrition grinding, and in the case of serpentine, by thermally activating the mineral by removing the chemically bound water. The effect of temperature is complex because it affects both the solubility of carbon dioxide and the rate of mineral dissolution in opposing fashions. Thus an optimum temperature for carbonation of olivine is approximately 185 degrees C and 155 degrees C for serpentine. This paper will elucidate the interaction of these variables and use kinetic studies to propose a process for the sequestration of the carbon dioxide.

Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K.; Penner, Larry R.

2003-01-01

391

Seasonal and interannual variability of oceanic carbon dioxide species at the U.S. JGOFS Bermuda Atlantic Time-series Study (BATS) site  

Microsoft Academic Search

The seasonal and interannual dynamics of the oceanic carbon cycle and the strength of air-sea exchange of carbon dioxide are poorly known in the North Atlantic subtropical gyre. Between October 1988 and December 1993, a time series of oceanic measurements of total carbon dioxide (TCO2), alkalinity (TA) and calculated pCO2 was obtained at the Bermuda Atlantic Time-series Study (BATS) site

Nicholas R. Bates; Anthony F. Michaels; Anthony H. Knap

1996-01-01

392

Reduction of soil carbon formation by tropospheric ozone under increased carbon dioxide levels.  

PubMed

In the Northern Hemisphere, ozone levels in the troposphere have increased by 35 per cent over the past century, with detrimental impacts on forest and agricultural productivity, even when forest productivity has been stimulated by increased carbon dioxide levels. In addition to reducing productivity, increased tropospheric ozone levels could alter terrestrial carbon cycling by lowering the quantity and quality of carbon inputs to soils. However, the influence of elevated ozone levels on soil carbon formation and decomposition are unknown. Here we examine the effects of elevated ozone levels on the formation rates of total and decay-resistant acid-insoluble soil carbon under conditions of elevated carbon dioxide levels in experimental aspen (Populus tremuloides) stands and mixed aspen-birch (Betula papyrifera) stands. With ambient concentrations of ozone and carbon dioxide both raised by 50 per cent, we find that the formation rates of total and acid-insoluble soil carbon are reduced by 50 per cent relative to the amounts entering the soil when the forests were exposed to increased carbon dioxide alone. Our results suggest that, in a world with elevated atmospheric carbon dioxide concentrations, global-scale reductions in plant productivity due to elevated ozone levels will also lower soil carbon formation rates significantly. PMID:14562100

Loya, Wendy M; Pregitzer, Kurt S; Karberg, Noah J; King, John S; Giardina, Christian P

2003-10-16

393

INFLUENCE OF ELEVATED OZONE AND CARBON DIOXIDE ON INSECT DENSITIES.  

SciTech Connect

The combustion of fossil fuels is profoundly altering the chemical composition of the atmosphere. Beginning with the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has increased from approximately 280 to 370 {micro}l l{sup -1} in 2004, and it is expected to exceed 550 {micro}l l{sup -1} by 2050. Tropospheric ozone has risen even more rapidly than CO{sub 2} and average summer concentrations in the Northern Hemisphere are expected to continue to increase by 0.5-2.5% per year over the next 30 years. Although elevated CO{sub 2} stimulates photosynthesis and productivity of terrestrial ecosystems, ozone (O{sub 3}) is deleterious. In addition to directly affecting the physiology and productivity of crops, increased concentrations of tropospheric CO{sub 2} and O{sub 3} are predicted to lower the nutritional quality of leaves, which has the potential to increase herbivory as insects eat more to meet their nutritional demands. We tested the hypothesis that changes in tropospheric chemistry affect the relationship between plants and insect herbivores by changing leaf quality. The susceptibility to herbivory of soybean grown in elevated CO{sub 2} or O{sub 3} was examined using free air gas concentration enrichment (SoyFACE). FACE technology has the advantage that plants are cultivated under realistic field conditions with no unwanted alteration of microclimate or artificial constraints on the insect community.

DELUCIA, E.; DERMODY, O.; O'NEILL, B.; ALDEA, M.; HAMILTON, J.; ZANGERL, A.; ROGER, A.; BERENBAUM, M.

2005-01-05

394

Effect of dissolved carbon dioxide on penicillin fermentations: mycelial growth and penicillin production. [Penicillium chrysogenum  

SciTech Connect

The effect of dissolved carbon dioxide on the specific growth rate and the penicillin production rate of Penicillium chrysogenum was examined experimentally. The dissolved carbon dioxide was found to inhibit the specific growth rate and the penicillin production rate when the aerated submerged penicillin fermentation was exposed to influent gases of 12.6 and 20% carbon dioxide, respectively. Upon exposure to influent gases of 3 and 5% carbon dioxide, no pronounced metabolic inhibition was noted.

Ho, C.S.; Smith, M.D.

1986-01-01

395

REDUCING THE UNCERTAINTY OF NORTH AMERICAN CARBON FLUX ESTIMATES USING AN EXTENDED ATMOSPHERIC CARBON DIOXIDE MEASUREMENT NETWORK.  

E-print Network

??We evaluate North American carbon fluxes using a monthly global Bayesian synthesis inversion that includes well-calibrated carbon dioxide concentrations measured at continental flux towers. We… (more)

Butler, Martha

2010-01-01

396

Numerically Simulating Carbonate Mineralization of Basalt with Injection of Carbon Dioxide into Deep Saline Formations  

SciTech Connect

The principal mechanisms for the geologic sequestration of carbon dioxide in deep saline formations include geological structural trapping, hydrological entrapment of nonwetting fluids, aqueous phase dissolution and ionization, and geochemical sorption and mineralization. In sedimentary saline formations the dominant mechanisms are structural and dissolution trapping, with moderate to weak contributions from hydrological and geochemical trapping; where, hydrological trapping occurs during the imbibition of aqueous solution into pore spaces occupied by gaseous carbon dioxide, and geochemical trapping is controlled by generally slow reaction kinetics. In addition to being globally abundant and vast, deep basaltic lava formations offer mineralization kinetics that make geochemical trapping a dominate mechanism for trapping carbon dioxide in these formations. For several decades the United States Department of Energy has been investigating Columbia River basalt in the Pacific Northwest as part of its environmental programs and options for natural gas storage. Recently this nonpotable and extensively characterized basalt formation is being reconsidered as a potential reservoir for geologic sequestration of carbon dioxide. The reservoir has an estimated storage capacity of 100 giga tonnes of carbon dioxide and comprises layered basalt flows with sublayering that generally alternates between low permeability massive and high permeability breccia. Chemical analysis of the formation shows 10 wt% Fe, primarily in the +2 valence. The mineralization reaction that makes basalt formations attractive for carbon dioxide sequestration is that of calcium, magnesium, and iron silicates reacting with dissolved carbon dioxide, producing carbonate minerals and amorphous quartz. Preliminary estimates of the kinetics of the silicate-to-carbonate reactions have been determined experimentally and this research is continuing to determine effects of temperature, pressure, rock composition and mineral assemblages on the reaction rates. This study numerically investigates the injection, migration and sequestration of supercritical carbon dioxide in deep Columbia River basalt formations using the multifluid subsurface flow and reactive transport simulator STOMP-CO2 with its ECKEChem module. Simulations are executed on high resolution multiple stochastic realizations of the layered basalt systems and demonstrate the migration behavior through layered basalt formations and the mineralization of dissolved carbon dioxide. Reported results include images of the migration behavior, distribution of carbonate formation, quantities of injected and sequestered carbon dioxide, and percentages of the carbon dioxide sequestered by different mechanisms over time.

White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Bacon, Diana H.

2006-07-08

397

Continual production of glycerol from carbon dioxide by Dunaliella tertiolecta.  

PubMed

Microalgae have high photosynthetic efficiencies and produce many valuable compounds from carbon dioxide. The Dunaliella genus accumulates glycerol, yet no commercial process currently exists for glycerol production from this microalga. Here it was found that in addition to intracellular accumulation, Dunaliella tertiolecta also releases glycerol into the external medium continuously, forming a large and stable carbon pool. The process is not affected by nutrient starvation or onset of cell death. Carbon dioxide was fixed at a constant rate, the bulk of it being channelled to extracellular glycerol (82%), resulting in enhanced photosynthetic carbon assimilation of 5 times that used for biomass production. The final extracellular glycerol concentration was 34 times the maximum concentration of intracellular glycerol; the latter declined further during cell death. Findings from this work will assist in the development of a bioconversion process to produce glycerol using D. tertiolecta without the need for cell harvest or disruption. PMID:23567730

Chow, Yvonne Y S; Goh, Serena J M; Su, Ziheng; Ng, Daphne H P; Lim, Chan Yuen; Lim, Natalie Y N; Lin, Huixin; Fang, Lei; Lee, Yuan Kun

2013-05-01

398

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

Electrobalance studies of calcination and carbonation of sodium bicarbonate materials were conducted at Louisiana State University. Calcination in an inert atmosphere was rapid and complete at 120 C. Carbonation was temperature dependent, and both the initial rate and the extent of reaction were found to decrease as temperature was increased between 60 and 80 C. A fluidization test apparatus was constructed at RTI and two sodium bicarbonate materials were fluidized in dry nitrogen at 22 C. The bed was completely fluidized at between 9 and 11 in. of water pressure drop. Kinetic rate expression derivations and thermodynamic calculations were conducted at RTI. Based on literature data, a simple reaction rate expression, which is zero order in carbon dioxide and water, was found to provide the best fit against reciprocal temperature. Simulations based on process thermodynamics suggested that approximately 26 percent of the carbon dioxide in flue gas could be recovered using waste heat available at 240 C.

David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

2001-05-01

399

Heterogeneous saline formations for carbon dioxide disposal: Impact of varying heterogeneity on containment and trapping  

Microsoft Academic Search

Natural gas fields often contain carbon dioxide in their reservoir fluids. Exploitation of these resources requires the removal of carbon dioxide from produced fluids to meet quality standards for sale into a domestic market or for the processing of the gas into LNG. To limit the atmospheric emissions of carbon dioxide, a major greenhouse gas, it has been proposed that

Matthew Flett; Randal Gurton; Geoff Weir

2007-01-01

400

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander  

E-print Network

Exergy analysis of transcritical carbon dioxide refrigeration cycle with an expander Jun Lan Yang is performed for the transcritical carbon dioxide refrigeration cycles with a throttling valve compression cycle is applicable for carbon dioxide for water heating and comfort cooling and heating [4

Bahrami, Majid

401

46 CFR 35.40-7 - Carbon dioxide alarm-T/ALL.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Carbon dioxide alarm-T/ALL. 35.40-7 Section 35.40-7 Shipping...OPERATIONS Posting and Marking Requirements-TB/ALL. § 35.40-7 Carbon dioxide alarm—T/ALL. Adjacent to all carbon dioxide fire...

2010-10-01

402

Carbon Dioxide Footprint of the Northwest Power System Comments submitted by Grant County Public Utility District  

E-print Network

Carbon Dioxide Footprint of the Northwest Power System Comments submitted by Grant County Public paper: Carbon Dioxide Footprint of the Northwest Power System, dated September 13, 2007. The Grant done a very thorough job of assessing the current and future carbon dioxide footprints of the Northwest

403

Carbon dioxide fluxes over bermudagrass, native prairie, and sorghum  

Microsoft Academic Search

The Bowen ratio\\/energy balance (BREB) method was used to measure 30min water vapor and carbon dioxide (CO2) fluxes over three fields dominated by different C4 grasses (bermudagrass, tallgrass native prairie, and sorghum) at the Blackland Research Center, Temple, TX. Fluxes were related to biotic and abiotic phenomena. Carbon accumulation rates calculated from BREB measurements were compared with those determined from

W. A Dugas; M. L Heuer; H. S Mayeux

1999-01-01

404

Carbon Dioxide Capture from Flue Gas Using Dry Regenerable Sorbents  

Microsoft Academic Search

Regenerable sorbents based on sodium carbonate (NaCO) can be used to separate carbon dioxide (CO) from coal-fired power plant flue gas. Upon thermal regeneration and condensation of water vapor, CO is released in a concentrated form that is suitable for reuse or sequestration. During the research project described in this report, the technical feasibility and economic viability of a thermal-swing

Thomas Nelson; David Green; Paul Box; Raghubir Gupta; Gennar Henningsen

2007-01-01

405

Carbon Dioxide Capture from Flue Gas Using Dry, Regenerable Sorbents  

SciTech Connect

This report describes research conducted between January 1, 2006, and March 31, 2006, on the use of dry regenerable sorbents for removal of carbon dioxide (CO{sub 2}) from coal combustion flue gas. An integrated system composed of a downflow co-current contact absorber and two hollow screw conveyors (regenerator and cooler) was assembled, instrumented, debugged, and calibrated. A new batch of supported sorbent containing 15% sodium carbonate was prepared and subjected to surface area and compact bulk density determination.

David A. Green; Thomas O. Nelson; Brian S. Turk; Paul D. Box; Raghubir P. Gupta

2006-03-31

406

Insensitivity of global warming potentials to carbon dioxide emission scenarios  

Microsoft Academic Search

GLOBAL warming potentials for radiatively active trace gases (such as methane and chlorofluorocarbons) have generally been expressed1-2 relative to the time-integrated climate forcing per unit emission of carbon dioxide. Previous attempts to estimate the integrated climate forcing per unit CO2 emitted have focused on perturbations to steady-state conditions in carbon-cycle models. But for non-steady-state conditions, the integrated climate forcing from

Ken Caldeira; James F. Kasting

1993-01-01

407

Photodissociation of carbon dioxide in the Mars upper atmosphere  

NASA Technical Reports Server (NTRS)

Calculation of the intensity of two of the emissions produced during the dissociative excitation of carbon dioxide in the upper atmosphere of Mars by solar ultraviolet radiation. The calculation tangential column emission rates of the atomic oxygen 2972-A line and the carbon monoxide Cameron bands produced by the photodissociative mechanism are found to be factors of 3 and 10, respectively, smaller than the emission rates observed by Mariner ultraviolet spectrometers.

Barth, C. A.

1974-01-01

408

Potential carbon dioxide fixation by industrially important microalgae  

Microsoft Academic Search

The present study aimed at investigating the carbon metabolism in terms of carbon dioxide fixation and its destination in microalgae cultivations. To this purpose, analysis of growth parameters, media of cultivation, biomass composition and productivity and nutrients balance were performed. Four microalgae suitable for mass cultivation were evaluated: Dunaliella tertiolecta SAD-13.86, Chlorella vulgaris LEB-104, Spirulina platensis LEB-52 and Botryococcus braunii

Eduardo Bittencourt Sydney; Wilerson Sturm; Julio Cesar de Carvalho; Vanete Thomaz-Soccol; Christian Larroche; Ashok Pandey; Carlos Ricardo Soccol

2010-01-01

409

Chinese Carbon Dioxide Satellite (TanSat) Status and Plans  

NASA Astrophysics Data System (ADS)

The Chinese carbon dioxide observation satellite (TanSat) project is the national high technology research and development program. It is funded by the ministry of science and technology of the people's republic of China and the Chinese Academy of Sciences. The TanSat will be launched in 2015, which is going to monitor the carbon dioxide in Sun-Synchronous orbit. The object of TanSat is to monitor XCO2 from space with precision of 1~4ppm. Two instruments will be onboard the TanSat, the main instrument is a high resolution grating spectrometer that measure reflected sunlight with the 0.76 ?m O2 A-band and two CO2 bands at 1.61 and 2.06 ?m, an airborne prototype of main instrument will be built and tested in the aircraft experiment. The second instrument is the Cloud and Aerosol Polarization Imager (CAPI), which is a wide field of view moderate resolution imaging spectrometer, it include 0.38, 0.67, 0.87, 1.375 and 1.64?m channels, with two polarization channels in 0.67?m and 1.64?m. A full physical optimal estimation method has being developed to retrieve the column-averaged CO2 dry air mole fraction (XCO2), and the data from CAPI will be used to correct cloud and aerosol interference. Currrently, the GOSAT data have been applied in the XCO2 retrieval system and reasonable results have been obtained. Global and regional surface CO2 flux will be derived from XCO2 observations with inverse modeling. Ground based validation stations are being established around China to observe CO2, Aerosol and Cloud. The CO2 observation consist of 3 Bruker IFS125 and 3 Optical Spectrum Analyzer over Beijing, Shenzhen, Shangdong, Inner Mongol, and Hainan Island, etc. Four phases of TanSat development is scheduled: design phase from Jan. 2011 to Aug. 2012, initial prototypes phase from Sept. 2012 to Sept. 2013, final prototypes phase from Oct. 2013 to Oct. 2014, launching and on-board testing phase from Nov. 2014 to June 2015.

Liu, Y.; Duan, M.; cai, Z.; Yang, D.; Lu, D.; Yin, Z.; Zheng, Y.; Yan, C.; Yang, Z.

2012-12-01

410

Geology of Bravo Dome carbon dioxide gas field, New Mexico  

Microsoft Academic Search

The Bravo Dome carbon dioxide gas field is located in Union and Harding Counties of northeast New Mexico. The Bravo Dome field covers approximately 800,000 acres, but areal boundaries of the field have not been fully defined. Production in 1989 was 113 bcf of gas from 272 wells. Cumulative production at the end of 1989 was 626 bcf. Estimated recoverable

1991-01-01

411

Extended-length fiber optic carbon dioxide monitoring  

NASA Astrophysics Data System (ADS)

This paper discusses the design and performance of fiber optic distributed intrinsic sensors for dissolved carbon dioxide, based on the use optical fibers fabricated so that their entire lengths are chemically sensitive. These fibers use a polymer-clad, silica-core structure where the cladding undergoes a large, reversible, change in optical absorbance in the presence of CO2. The local "cladding loss" induced by this change is thus a direct indication of the carbon dioxide concentration in any section of the fiber. To create these fibers, have developed a carbon dioxide-permeable polymer material that adheres well to glass, is physically robust, has a refractive index lower than fused silica, and acts as excellent hosts for a unique colorimetric indicator system that respond to CO2. We have used this proprietary material to produce carbon-dioxide sensitive fibers up to 50 meters long, using commercial optical fiber fabrication techniques. The sensors have shown a measurement range of dissolved CO2 of 0 to 1,450 mg/l (0 to 100% CO2 saturation), limit of detection of 0.3 mg/l and precision of 1.0 mg/l in the 0 to 50 mg/l dissolved CO2 range, when a 5 meter-long sensor fiber segment is used. Maximum fiber length, minimum detectable concentration, and spatial resolution can be adjusted by adjusting indicator concentration and fiber design.

Delgado-Alonso, Jesus; Lieberman, Robert A.

2013-05-01

412

Molecular simulations of carbon dioxide and water: cation solvation.  

PubMed

Proposed carbon dioxide sequestration scenarios in sedimentary reservoirs require investigation into the interactions between supercritical carbon dioxide, brines, and the mineral phases found in the basin and overlying caprock. Molecular simulations can help to understand the partitioning of metal cations between aqueous solutions and supercritical carbon dioxide where limited experimental data exist. In this effort, we used classical molecular dynamics simulations to compare the solvation of alkali and alkaline-earth metal cations in water and liquid CO(2) at 300 K by combining a flexible simple point charge model for water and an accurate flexible force field for CO(2). Solvation energies for these cations are larger in water than in carbon dioxide, suggesting that they will partition preferentially into water. In both aqueous and CO(2) solutions, the solvation energies decrease with cation size and increase with cation charge. However, changes in solvation energy with ionic radii are smaller in CO(2) than in water suggesting that the partitioning of cations into CO(2) will increase with ion size. Simulations of the interface between aqueous solution and supercritical CO(2) support this suggestion in that some large cations (e.g., Cs(+) and K(+)) partition into the CO(2) phase, often with a partial solvation sphere of water molecules. PMID:22779448

Criscenti, Louise J; Cygan, Randall T

2013-01-01

413

Counter-current carbon dioxide extraction of soy skim  

Technology Transfer Automated Retrieval System (TEKTRAN)

The use of carbon dioxide in a counter-current fractionation column was investigated as a means to remove residual fat from soy skim after enzyme-assisted aqueous extraction of soybeans. The stainless steel column was 1.2 meters long with an internal diameter of 1.75 cm and filled protruded stainles...

414

The Subsurface Fluid Mechanics of Geologic Carbon Dioxide Storage  

E-print Network

The Subsurface Fluid Mechanics of Geologic Carbon Dioxide Storage by Michael Lawrence Szulczewski S the fluid mechanics of CO2 storage, with the goal of informing two practical questions. The first question by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heidi M. Nepf Chair, Departmental Committee for Graduate Students #12;2 #12;The Subsurface Fluid

415

Carbon Dioxide Production and Sodium Transport by the Toad Bladder  

Microsoft Academic Search

IN order to investigate further the relationship of cellular metabolism to active ion transport, we have correlated carbon dioxide production with sodium transport by the urinary bladder of the toad, Bufo marinus, in vitro. The toad bladder was mounted so as to separate the two halves of a glass chamber, and each side was bathed with a phosphate Ringer's solution

Roy H. Maffly; Cecil H. Coggins

1965-01-01

416

Climate change and carbon dioxide storage Herbert E. Huppert  

E-print Network

1 Climate change and carbon dioxide storage Herbert E. Huppert Institute of Theoretical, spread material in a roughly symmetric fashion. Particulate matter, or planetesmials, came on Earth having been found in Australia. Of course the Earth has changed dramatically over these four

Huppert, Herbert

417

Carbon dioxide rapid superpulsed laser treatment of erythroplasia of Queyrat.  

PubMed

A single case of erythroplasia of Queyrat successfully treated by rapid superpulsed carbon dioxide laser emission is presented. The results of this single case and previous studies are compared with thos obtained by different modalities used in the past. PMID:6773202

Rosemberg, S K; Fuller, T A

1980-08-01

418

The Concentration of Atmospheric Carbon Dioxide in Hawaii  

Microsoft Academic Search

The concentration of atmospheric carbon dioxide at and near Mauna Loa Ob- servatory, Hawaii, is reported for the first six years (1958-1963) of a long-term program to document the effects of the combustion of coal and petroleum on the distribution of COs gas in the atmosphere and in the world's oceans. The majority of the measurements reported here were obtained

Jack C. Pales; Charles D. Keeling

1965-01-01

419

Global Warming: Carbon Dioxide and the Greenhouse Effect  

NSDL National Science Digital Library

This video segment demonstrates carbon dioxide's role in the greenhouse effect and explains how increasing concentrations of C02 in the atmosphere may be contributing to global warming. Video includes an unusual demonstration of C02's heat-absorbing properties, using infrared film, a researcher's face, and a stream of C02 between them.

FRONTLINE/NOVA

420

Carbon dioxide supersaturation in the surface waters of lakes  

Microsoft Academic Search

Data on the partial pressure of carbon dioxide (COâ) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within {+-}20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure

J. J. Cole; N. F. Caraco; G. W. Kling; T. K. Kratz

1994-01-01

421

Using the 5E Learning Cycle Sequence with Carbon Dioxide  

ERIC Educational Resources Information Center

The authors used the 5E learning cycle (engage, explore, explain, extend, and evaluate) and a pulmonary carbon dioxide mystery to introduce eighth grade students to the study of chemistry. The activity engages students in measurement, data collection, data analysis, media and internet research, research design, and report writing as they search…

Schlenker, Richard M.; Blanke, Regina; Mecca, Peter

2007-01-01

422

40 CFR 86.1524 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2012 CFR

...Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New...Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1524 Carbon dioxide analyzer...

2012-07-01

423

40 CFR 86.1524 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2010 CFR

...Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New...Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1524 Carbon dioxide analyzer...

2010-07-01

424

40 CFR 86.1524 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2013 CFR

...Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New...Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1524 Carbon dioxide analyzer...

2013-07-01

425

40 CFR 86.1524 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2011 CFR

...Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New...Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1524 Carbon dioxide analyzer...

2011-07-01

426

40 CFR 86.1524 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2014 CFR

...Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New...Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1524 Carbon dioxide analyzer...

2014-07-01

427

Carbon dioxide flash-freezing applied to ice cream production  

E-print Network

(cont.) Carbon dioxide is recompressed from 1.97 x 106 Pa (285 psi) to 3.96 x 106 Pa (575 psi). The process is scaled by increasing the number of nozzles to accommodate the desired flow rate. Only 165 nozzles are required ...

Peters, Teresa Baker, 1981-

2006-01-01

428

27 CFR 24.319 - Carbon dioxide record.  

Code of Federal Regulations, 2013 CFR

A proprietor who uses carbon dioxide in still wine shall maintain a record of the laboratory tests conducted to establish compliance with the limitations prescribed in § 24.245. (Sec. 201, Pub. L. 85-859, 72 Stat. 1381, as amended (26 U.S.C....

2013-04-01

429

46 CFR 196.37-9 - Carbon dioxide alarm.  

Code of Federal Regulations, 2010 CFR

46 ? Shipping ? 7 ? 2010-10-01 ? 2010-10-01 ? false ? Carbon dioxide alarm. ? 196.37-9 ? Section 196.37-9 ? Shipping ? COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ? OCEANOGRAPHIC RESEARCH VESSELS ? OPERATIONS ? Markings for Fire and Emergency Equipment, etc. ? § 196.37-9 ?...

2010-10-01

430

46 CFR 196.37-9 - Carbon dioxide alarm.  

Code of Federal Regulations, 2011 CFR

46 ? Shipping ? 7 ? 2011-10-01 ? 2011-10-01 ? false ? Carbon dioxide alarm. ? 196.37-9 ? Section 196.37-9 ? Shipping ? COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ? OCEANOGRAPHIC RESEARCH VESSELS ? OPERATIONS ? Markings for Fire and Emergency Equipment, etc. ? § 196.37-9 ?...

2011-10-01

431

40 CFR 86.224-94 - Carbon dioxide analyzer calibration.  

Code of Federal Regulations, 2012 CFR

Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.224-94 Carbon dioxide analyzer calibration. The provisions of §...

2012-07-01

432

Modeling Seasonality in Carbon Dioxide Emissions From Fossil Fuel Consumption  

Microsoft Academic Search

Using United States data, a method is developed to estimate the monthly consumption of solid, liquid and gaseous fossil fuels using monthly sales data to estimate the relative monthly proportions of the total annual national fossil fuel use. These proportions are then used to estimate the total monthly carbon dioxide emissions for each state. From these data, the goal is

P. Kishore; K. Igarashi; H. Oikawa; M. Uotome; J. S. Gregg; R. J. Andres

2004-01-01

433

Corrosion of various engineering alloys in supercritical carbon dioxide  

E-print Network

The corrosion resistance of ten engineering alloys were tested in a supercritical carbon dioxide (S-CO 2) environment for up to 3000 hours at 610°C and 20MPa. The purpose of this work was to evaluate each alloy as a potential ...

Gibbs, Jonathan Paul

2010-01-01

434

Treatment of chronic lip fissures with carbon dioxide laser  

Microsoft Academic Search

Resurfacing of cutaneous tissue with carbon dioxide laser increases the amount and quality of collagen and elastin subepithelially. We used this technique to ablate 12 chronic lip fissures in one woman and 10 men. Five patients’ fissures had persisted for durations ranging from several months to seven years; the other six had fissures that split between one and five times

James Combes; Timothy K. Mellor

2009-01-01

435

Elevated Carbon Dioxide and Ozone Concentrations Alter Soybean Antioxidant Metabolism  

Technology Transfer Automated Retrieval System (TEKTRAN)

One important mechanism by which plants sense and respond to their environment is through redox control. Oxidative damage at the cellular level can feed forward to decrease leaf photosynthesis and therefore canopy and ecosystem productivity. How rising atmospheric carbon dioxide (CO2) and tropospher...

436

How Can We Use Carbon Dioxide as a Solvent?  

ERIC Educational Resources Information Center

This article describes the work being undertaken to make more use of supercritical carbon dioxide as a green solvent. It discusses how the use of surfactants can address the limitations of supercritical CO[subscript 2] in dissolving solutes that are polar and of higher molecular weight. The design of appropriate hydrocarbon CO[subscript 2]-philic…

Mohamed, Azmi; Eastoe, Julian

2011-01-01

437

Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment  

ERIC Educational Resources Information Center

Background: We tested the hypothesis that classroom carbon dioxide (CO[subscript 2]) concentration is inversely related to child school attendance and educational attainment. Methods: Concentrations of CO[subscript 2] were measured over a 3-5?day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of…

Gaihre, Santosh; Semple, Sean; Miller, Janice; Fielding, Shona; Turner, Steve

2014-01-01

438

Environmental Challenges: Radon and Carbon Dioxide in School Buildings.  

ERIC Educational Resources Information Center

Many school buildings with high radon levels also exhibit high carbon dioxide levels that starve the minds of students for oxygen. Administrators must realize that the world's best educator cannot teach minds made dysfunctional by their environment. This article describes Environmental Protection Agency testing results and offers radon monitoring…

Krueger, James

1991-01-01

439

Biodiversity and biological impact of ocean disposal of carbon dioxide  

SciTech Connect

Five major characteristics of deep-sea organisms that are relevant to the carbon dioxide ocean sequestration are pointed out. They are (1) low biological activities, (2) long life span, (3) high sensitivity to the environmental disturbance, (4) high species diversity, and (5) low density. These characteristics suggest the deep-sea species are sensitive to the environmental disturbance, and once they are damaged, they may easily become extinct or it might take a long time to recover. To get public acceptance for ocean sequestration of carbon dioxide, the authors need a reliable assessment of its affects on the deep-sea ecosystem based on an accurate model. For a better modeling, data regarding the long-term (chronic) effect of slightly increased concentration of carbon dioxide on the deep-sea organisms are prerequisite. Precise data regarding such biological characteristics can be obtained only from in-situ experiments. To develop a system for ecophysiological in-situ experiments of deep-sea organisms is thus as important as solving the technological problems related to the ocean sequestration of carbon dioxide.

Shirayama, Yoshihisa [Univ. of Tokyo (Japan)] [Univ. of Tokyo (Japan)

1998-07-01

440

2008 Nature Publishing Group Atmospheric carbon dioxide linked  

E-print Network

.29 The relationship between atmospheric carbon dioxide (CO2) and climate in the Quaternary period has been extensively . The range of geological evidence for cool periods during the high CO2 Mesozoic `greenhouse world'2,3 of high and theoretical modelling6,7 . These records indicate that atmospheric CO2 rose from 420 p.p.m.v. in the Triassic

Cai, Long

441

Carbon dioxide fixation by microalgae cultivated in open bioreactors  

Microsoft Academic Search

The biofixation of carbon dioxide (CO2) by microalgae has been proven to be an efficient and economical method, mainly due to the photosynthetic ability of these microorganisms to use this gas as a source of nutrients for their development. The aim of this work was to study the growth of Spirulina LEB18 and Chlorella kessleri microalgae, exposed to controlled and

Ana Priscila Centeno da Rosa; Lisiane Fernandes Carvalho; Luzia Goldbeck; Jorge Alberto Vieira Costa

2011-01-01

442

SELECTIVE OXIDATION IN SUPERCRITICAL CARBON DIOXIDE USING CLEAN OXIDANTS  

EPA Science Inventory

We have systematically investigated heterogeneous catalytic oxidation of different substrates in supercritical carbon dioxide (SC-CO2). Three types of catagysts: a metal complex, 0.5% platinum g-alumina and 0.5% palladium g-alumina were used at a pressure of 200 bar, temperatures...

443

Household carbon dioxide production in relation to the greenhouse effect  

Microsoft Academic Search

A survey of 655 households from eastern suburbs of Melbourne was undertaken to determine householders[prime] attitudes to, and understanding of, the greenhouse effect. Carbon dioxide emissions resulting from car, electricity and gas use were computed and household actions which could reduce CO[sub 2] emissions were addressed. Preliminary analysis of the results indicates that householders in this area are aware of,

D. Stokes; A. Lindsay; J. Marinopoulos; A. Treloar; G. Wescott

1994-01-01

444

Raising the Level of Carbon Dioxide in Your Blood  

NSDL National Science Digital Library

In this activity (on page 146 of the PDF), learners will explore the effects of increased carbon dioxide in the bloodstream. This activity can be enhanced by sharing the "Astronaut's Sleep" Podcast with learners (see related resource link). This resource guide includes background information and sample evaluation questions. Note: learners with respiratory ailments should not participate as subjects.

Marlene Y. MacLeish

2013-05-15

445

Using carbon dioxide as a tracer to measure ventilation in a school  

SciTech Connect

The health implications of biological, chemical and physical contamination of schools has provided an impetus for determining the level of exposures in school buildings. The overall objective of this study was to measure and evaluate the indoor air quality at the middle school with an emphasis on characterizing baseline conditions. The focus of this paper is the relationship between occupancy and measured concentrations of carbon dioxide, and an evaluation of the use of carbon dioxide as a tracer for ventilation in the school. A middle school (grades 6 to 8) in a residential section of Springfield, IL area was selected for this baseline indoor air quality survey. The school was characterized as having no health complaints, good maintenance schedules, did not contain carpeting within the classrooms or hallways, did not have any significant remodeling and had agreed to allow the sampling to take place during school hours. Monitoring closely following the guidelines recommended in the Preliminary Draft: Conceptual Standardized EPA Protocol For Characterizing Indoor Air Quality in School Buildings. Four indoor locations including the Cafeteria, a Science Classroom, an Art Classroom, and the Lobby outside of the main office, and one outdoor location were sampled for various environmental comfort and pollutant parameters for one week in February, 1997. Continuous measurements of carbon dioxide were logged at all locations for five days. A measurement survey of mechanical and natural ventilation rates was completed three times per day on each of the three particle sampling days. Information on ventilation system operation and detailed logs of activity were also collected at each indoor monitoring location throughout the study. A consistent relationship between hourly occupancy and corresponding carbon dioxide concentrations was seen.

Scheff, P.A.; Paulius, V.K.; Huang, S.W.; Conroy, L.M.

1999-07-01

446

Introduction of Chinese Carbon Dioxide Satellite (TanSat) Mission  

NASA Astrophysics Data System (ADS)

It is well known that the increase in atmospheric CO2 and CH4 (long-lived greenhouse gases; GHG) due to anthropogenic activity is the dominant process driving global climate change. Space-based measurements of GHGs with high precision, resolution, and global coverage are urgently needed to characterize the geographic distribution of their sources and sinks and quantify their roles in the atmospheric CO2 budget. As a large developing country, China has the highest level of GHG emissions. The Chinese government is seeking sustainable development and hence is trying to reduce GHG emissions. The ministry of science and technology of the people’s republic of China had started the Chinese carbon dioxide observation satellite (TanSat) mission 3 years ago, currently the science requirement review and preliminary design review phases had been finished. The prototype of 3 channel high resolution grating spectrometer for CO2 measurement has been manufactured and tested, and the Cloud and Aerosol Polarization Imager (CAPI) is manufactured on schedule. To support TanSat mission, a full physical optimal estimation method has being developed to retrieve the column-averaged CO2 dry air mole fraction (XCO2), and the GOSAT data have been applied in the XCO2 retrieval system and reasonable results have been achieved. Global and regional CO2 flux will be derived from XCO2 observations with inverse modeling- Chinese Carbon Cycle Data Assimilation System (Tan-Tracker). Ground based measurement stations have being established around China to validate satellite observation. They consist of 3 Bruker IFS125, 3 Optical Spectrum Analyzer (OSA) and other instruments over different parts of China. TanSat is scheduled to be launched at the end of 2015.

Liu, Yi

447

Tracing Changes in Ecosystem Function under Elevated Carbon Dioxide Conditions  

NSDL National Science Digital Library

This peer-reviewed article from BioScience journal is on the effects of elevated carbon dioxide on the ecosystem. Responses of ecosystems to elevated levels of atmospheric carbon dioxide (CO2) remain a critical uncertainty in global change research. Two key unknown factors are the fate of carbon newly incorporated by photosynthesis into various pools within the ecosystem and the extent to which elevated CO2 is transferred to and sequestered in pools with long turnover times. The CO2 used for enrichment in many experiments incorporates a dual isotopic tracer, in the sense that ratios of both the stable carbon-13 (13C) and the radioactive carbon-14 (14C) isotopes with respect to carbon-12 are different from the corresponding ratios in atmospheric CO2. Here we review techniques for using 13C and 14C abundances to follow the fate of newly fixed carbon and to further our understanding of the turnover times of ecosystem carbon pools. We also discuss the application of nitrogen, oxygen, and hydrogen isotope analyses for tracing changes in the linkages between carbon, nitrogen, and water cycles under conditions of elevated CO2.

DIANE E. PATAKI, DAVID S. ELLSWORTH, R. DAVE EVANS, MIQUEL GONZALEZ-MELER, JOHN KING, STEVEN W. LEAVITT, GUANGHUI LIN, ROSER MATAMALA, ELISE PENDALL, ROLF SIEGWOLF, CHRIS VAN KESSEL, and JAMES R. EHLERINGER (;)

2003-09-01

448

Carbon Dioxide: The Heat is On  

NSDL National Science Digital Library

In this activity, students will observe the effect of the gases resulting from a burned fossil fuel on the heat absorption of air and determine the ability of phytoplankton to remove greenhouse gases from the atmosphere. This activity is part of a set of three activities exploring the effects of phytoplankton on water and air.

Dawson, Besse

449

The redox combustion of carbon monoxide for recovering pure carbon dioxide by using molten (Na+,K+)2(CO32-,SO42-) mixtures.  

PubMed

Large-scale combustion systems, such as thermal power plants, emit large amounts of carbon dioxide, which can increase global warming. A molten salt redox combustion system was proposed to recover pure carbon dioxide exhausted from the combustion of fossil fuels. This system is composed of two successive processes by using reactions occurring in a molten salt. The molten salt is the mixture of the molten alkali metal sulfates and carbonates. The sulfate ions oxidize the fuels in first processes, being changed to reductive species such as sulfide ions. In this process, carbon dioxide and water are exclusively exhausted. The reductive species of sulfur compounds are oxidized to regenerate the sulfate ions by air in the second process. In this study, these above two processes were tried by using molten [(Na(+))(0.5),(K(+))(0.5)](2)[(CO(3)(2-))(0.9),(SO(4)(2-))(0.1)] alternatively. The oxidation of carbon monoxide as fuel by sulfate ions and the regeneration of sulfate ions by air were investigated in the temperature range of 700-950 degrees C, respectively. These reactions were exothermic. The rate of the regeneration of the sulfate ions was extremely high. During the oxidation of carbon monoxide, the reaction was first order in carbon monoxide with an activation energy of 101 kJ mol(-1). The optimum condition to recover pure carbon dioxide on practical operation was discussed. PMID:16337672

Shimano, Satoshi; Asakura, Shukuji

2006-06-01

450

Supercritical carbon dioxide cycle control analysis.  

SciTech Connect

This report documents work carried out during FY 2008 on further investigation of control strategies for supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle energy converters. The main focus of the present work has been on investigation of the S-CO{sub 2} cycle control and behavior under conditions not covered by previous work. An important scenario which has not been previously calculated involves cycle operation for a Sodium-Cooled Fast Reactor (SFR) following a reactor scram event and the transition to the primary coolant natural circulation and decay heat removal. The Argonne National Laboratory (ANL) Plant Dynamics Code has been applied to investigate the dynamic behavior of the 96 MWe (250 MWt) Advanced Burner Test Reactor (ABTR) S-CO{sub 2} Brayton cycle following scram. The timescale for the primary sodium flowrate to coast down and the transition to natural circulation to occur was calculated with the SAS4A/SASSYS-1 computer code and found to be about 400 seconds. It is assumed that after this time, decay heat is removed by the normal ABTR shutdown heat removal system incorporating a dedicated shutdown heat removal S-CO{sub 2} pump and cooler. The ANL Plant Dynamics Code configured for the Small Secure Transportable Autonomous Reactor (SSTAR) Lead-Cooled Fast Reactor (LFR) was utilized to model the S-CO{sub 2} Brayton cycle with a decaying liquid metal coolant flow to the Pb-to-CO{sub 2} heat exchangers and temperatures reflecting the decaying core power and heat removal by the cycle. The results obtained in this manner are approximate but indicative of the cycle transient performance. The ANL Plant Dynamics Code calculations show that the S-CO{sub 2} cycle can operate for about 400 seconds following the reactor scram driven by the thermal energy stored in the reactor structures and coolant such that heat removal from the reactor exceeds the decay heat generation. Based on the results, requirements for the shutdown heat removal system may be defined. In particular, the peak heat removal capacity of the shutdown heat removal loop may be specified to be 1.1 % of the nominal reactor power. An investigation of the oscillating cycle behavior calculated by the ANL Plant Dynamics Code under specific conditions has been carried out. It has been found that the calculation of unstable operation of the cycle during power reduction to 0 % may be attributed to the modeling of main compressor operation. The most probable reason for such instabilities is the limit of applicability of the currently used one-dimensional compressor performance subroutines which are based on empirical loss coefficients. A development of more detailed compressor design and performance models is required and is recommended for future work in order to better investigate and possibly eliminate the calculated instabilities. Also, as part of such model development, more reliable surge criteria should be developed for compressor operation close to the critical point. It is expected that more detailed compressor models will be developed as a part of validation of the Plant Dynamics Code through model comparison with the experiment data generated in the small S-CO{sub 2} loops being constructed at Barber-Nichols Inc. and Sandia National Laboratories (SNL). Although such a comparison activity had been planned to be initiated in FY 2008, data from the SNL compression loop currently in operation at Barber Nichols Inc. has not yet become available by the due date of this report. To enable the transient S-CO{sub 2} cycle investigations to be carried out, the ANL Plant Dynamics Code for the S-CO{sub 2} Brayton cycle was further developed and improved. The improvements include further optimization and tuning of the control mechanisms as well as an adaptation of the code for reactor systems other than the Lead-Cooled Fast Reactor (LFR). Since the focus of the ANL work on S-CO{sub 2} cycle development for the majority of the current year has been on the applicability of the cycle to SFRs, work has started on modification of the ANL Plant Dynamics Code to allow

Moisseytsev, A.; Sienicki, J. J. (Nuclear Engineering Division)

2011-04-11

451

Tropical deforestation and atmospheric carbon dioxide  

Microsoft Academic Search

Recent estimates of the net release of carbon to the atmosphere from deforestation in the tropics have ranged between 0.4 and 2.5 × 1015 g yr-1. Two things have happened to require a revision of these estimates. First, refinements of the methods used to estimate the stocks of carbon in the vegetation of tropical forests have produced new estimates that

R. A. Houghton

1991-01-01

452

Application of carbon nanotube in wireless sensor network to monitor carbon dioxide  

Microsoft Academic Search

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Over the years, new discoveries have led to new applications, often taking advantage of their unique electrical properties, extraordinary strength and efficiency in heat conduction. Since industrialisation, human activities have resulted in steadily increasing concentrations of the greenhouse gases. Excess amount of carbon dioxide (CO2) in living environment is

Othman Sidek; S. A. Quadri; Shahid Kabir; Muhammad Hassan Bin Afzal

2012-01-01

453

Potential climate change effects on rice: Carbon dioxide and temperature  

SciTech Connect

The projected doubling of current levels of atmospheric CO{sub 2} concentration [CO{sub 2}] during the next century, along with increases in other radiatively active gases, has led to predictions of increases in global air temperature and shifts in precipitation patterns. Since 1987, several [CO{sub 2}] and temperature experiments have been conducted on rice (Oryza sativa L., cv. IR-30) in outdoor, naturally-sunlit, environmentally-controlled, plant growth chambers. The objectives of this chapter are to summarize some of the major findings of these experiments. In these experiments, season-long [CO{sub 2}] treatments ranged from 160 to 900 {micro}mol CO{sub 2} mol{sup {minus}1} air, while temperature treatments ranged from 25/18/21 to 40/33/37 C (daytime dry bulb air temperature/nighttime dry bulb air temperature/constant paddy water temperature). Total growth duration was shortened by 10 to 12 d as [CO{sub 2}] increased across a [CO{sub 2}] range from 160 to 500 {micro}mol mol{sup {minus}1}, due mainly to a shortened vegetative phase of development and a reduction in the number of mainstem leaves formed prior to panicle initiation. Photosynthesis, growth, and final grain yield increased with [CO{sub 2}] from 160 to 500 {micro}mol mol{sup {minus}1}, but were very similar from 500 to 900 {micro}mol mol{sup {minus}1}. Carbon dioxide enrichment from 330 to 660 {micro}mol mol{sup {minus}1} increased grain yield mainly by increasing the number of panicles per plant, and increasing temperature treatment above 28/21/25 C resulted in decreased grain yield, due largely to a decline in the number of filled grain per panicle. Evapotranspiration decreased and water-use efficiency increased with increasing [CO{sub 2}] treatment, while the reverse trends were found with increasing temperature treatment. 60 refs., 7 figs., 2 tabs.

Baker, J.T.; Boote, K.J. [Univ. of Florida, Gainesville, FL (United States); Allen, L.H. Jr. [USDA-ARS, Gainesville, FL (United States); [Univ. of Florida, Gainesville, FL (United States)

1995-12-31

454

A 400 million year carbon isotope record of pedogenic carbonate: Implications for paleoatmospheric carbon dioxide  

SciTech Connect

A 400 record of atmospheric carbon dioxide levels has been estimated by applying a CO{sub 2} paleobarometer to a database of 758 analyses of paleosol (fossil soil) carbonates. This database is a compilation of new data and previously published values from the literature. Many new analyses of Mesozoic paleosols are reported, an era poorly represented in the literature. Results indicate that large fluctuations in atmospheric carbon dioxide levels have occurred over the study interval, ranging from the current level up to ten times the current level. Declining pCO{sub 2} levels through the middle Paleozoic culminate in low levels in the Early Permian. An abrupt increase in pCO{sub 2} in the Early Permian is followed by a decrease prior to the Permo-Triassic boundary. Carbon dioxide levels increase through the Triassic to approx. 3,000 ppmV, a level maintained through the Jurassic period. Levels lowered through the Cretaceous, dropping to less than 1,000 ppmV prior to the Cretaceous-Tertiary boundary. Relatively low levels persisted throughout the Cenozoic, with some evidence of higher levels in the Eocene and Oligocene.

Ekart, D.D.; Cerling, T.E.; Montanez, I.P.; Tabor, N.J.

1999-12-01

455

Chalcogen-bonded complexes of some carbon dioxide analogues  

NASA Astrophysics Data System (ADS)

Ab initio calculations have been carried out on the sulphur-bonded van der Waals complexes formed between the carbon dioxide analogues carbonyl sulphide, carbon disulphide and thiocarbonyl selenide, and the common electron donors ammonia, water, phosphine and hydrogen sulphide. The structures of these twelve complexes are all similar, and involve an approximately linear XCS⋯Y fragment (X = O, S, Se; Y = N, O, P, S). These structures contrast with those of the oxygen-bound complexes of carbon dioxide, carbonyl sulphide and carbonyl selenide reported earlier which, with the exception of the hydrogen sulphide species, are characterized by four-membered rings with varying orientations involving the C, O, H and Y atoms. The molecular structures, interaction energies and vibrational spectra have been studied, and the variations in these properties have been correlated with the complex structures and with the molecular quadrupole moments of the acid monomers.

Ramasami, Ponnadurai; Ford, Thomas A.

2014-08-01

456

Geochemical consequences of increased atmospheric carbon dioxide on coral reefs  

USGS Publications Warehouse

A coral reef represents the net accumulation of calcium carbonate (CaCO3) produced by corals and other calcifying organisms. If calcification declines, then reef-building capacity also declines. Coral reef calcification depends on the saturation state of the carbonate mineral aragonite of surface waters. By the middle of the next century, an increased concentration of carbon dioxide will decrease the aragonite saturation state in the tropics by 30 percent and biogenic aragonite precipitation by 14 to 30 percent. Coral reefs are particularly threatened, because reef-building organisms secrete metastable forms of CaCO3, but the biogeochemical consequences on other calcifying marine ecosystems may be equally severe.

Kleypas, J.A.; Buddemeier, R.W.; Archer, D.; Gattuso, J.-P.; Langdon, C.; Opdyke, B.N.

1999-01-01

457

Modification of pure oxygen absorption equipment for concurrent stripping of carbon dioxide  

USGS Publications Warehouse

The high solubility of carbon dioxide precludes significant desorption within commercial oxygen absorption equipment. This operating characteristic of the equipment limits its application in recirculating water culture systems despite its ability to significantly increase allowable fish loading rates (kg/(L min)). Carbon dioxide (DC) is typically removed by air stripping. This process requires a significant energy input for forced air movement, air heating in cold climates and water pumping. We developed a modification for a spray tower that provides for carbon dioxide desorption as well as oxygen absorption. Elimination of the air-stripping step reduces pumping costs while allowing dissolved nitrogen to drop below saturation concentrations. This latter response provides for an improvement in oxygen absorption efficiency within the spray tower. DC desorption is achieved by directing head-space gases from the spray tower (O2, N2, CO2) through a sealed packed tower scrubber receiving a 2 N NaOH solution. Carbon dioxide is selectively removed from the gas stream, by chemical reaction, forming the product Na 2CO3. Scrubber off-gas, lean with regard to carbon dioxide but still rich with oxygen, is redirected through the spray tower for further stripping of DC and absorption of oxygen. Make-up NaOH is metered into the scrubbing solution sump on an as needed basis as directed by a feedback control loop programmed to maintain a scrubbing solution pH of 11.4-11.8. The spent NaOH solution is collected, then regenerated for reuse, in a batch process that requires relatively inexpensive hydrated lime (Ca(OH)2). A by-product of the regeneration step is an alkaline filter cake, which may have use in bio-solids stabilization. Given the enhanced gas transfer rates possible with chemical reaction, the required NaOH solution flow rate through the scrubber represents a fraction of the spray tower water flow rate. Further, isolation of the water being treated from the atmosphere (1), allows for an improvement in oxygen absorption efficiency by maintaining DN well below local saturation concentrations (2), minimizes building energy requirements related to heating and ventilation and (3), reduces the potential for pathogen transmittance. We report on the performance of a test scrubber evaluated over a range of NaOH solution temperatures, pH, packing irrigation rates, and gas stream compositions. We also describe our experience with the process in a pilot scale recirculating water (trout) production system.

Watten, B.J.; Sibrell, P.L.; Montgomery, G.A.; Tsukuda, S.M.

2004-01-01

458

Overview of International Space Station Carbon Dioxide Removal Assembly On-Orbit Operations and Performance  

NASA Technical Reports Server (NTRS)

Controlling Carbon Dioxide (CO2) partial pressure in the habitable vehicle environment is a critical part of operations on the International Space Station (ISS). On the United States segment of ISS, CO2 levels are primarily controlled by the Carbon Dioxide Removal Assembly (CDRA). There are two CDRAs on ISS; one in the United States Laboratory module, and one in the Node3 module. CDRA has been through several significant operational issues, performance issues and subsequent re-design of various components, primarily involving the Desiccant Adsorbent Bed (DAB) assembly and Air Selector Valves (ASV). This paper will focus on significant operational and performance issues experienced by the CDRA team from 2008-2012.

Matty, Christopher M.

2013-01-01

459

PMEL CO2: Carbon Dioxide Program  

NSDL National Science Digital Library

In order to advance a shared scientific understanding of the ocean's carbon cycle and how it continues to change over time, the National Oceanic and Atmospheric Administration (NOAA) continues to investigate the evolving state of the ocean carbon chemistry with high quality measurements on ships and autonomous platforms. This website provides information on their public outreach efforts, along with news features on how these changes may affect everything from marine animal populations to tourism operations. On the homepage, visitors should check out the "Map & Data Viewer", which allows them to look at the collected carbon data via a 3D projection. The site also contains a "Data Portal" which allows interested parties to examine the data that has been collected thus far, along with historical data sets. The site is rounded out by sections that cover their ongoing research projects and their current observations on these changes.

460

Potential carbon dioxide fixation by industrially important microalgae.  

PubMed

The present study aimed at investigating the carbon metabolism in terms of carbon dioxide fixation and its destination in microalgae cultivations. To this purpose, analysis of growth parameters, media of cultivation, biomass composition and productivity and nutrients balance were performed. Four microalgae suitable for mass cultivation were evaluated: Dunaliella tertiolecta SAD-13.86, Chlorella vulgaris LEB-104, Spirulina platensis LEB-52 and Botryococcus braunii SAG-30.81. Global rates of carbon dioxide and oxygen were determinated by a system developed in our laboratory. B. braunii presented the highest CO(2) fixation rate, followed by S. platensis,D. tertiolecta and C. vulgaris (496.98, 318.61, 272.4 and 251.64 mg L(-1)day(-1), respectively). Carbon dioxide fixated was mainly used for microalgal biomass production. Nitrogen, phosphorus (calcium for D. tertiolecta), potassium and magnesium consumption rates (mg gX(-1)) were evaluated for the four microalgae. Biomass composition presented a predominance of proteins but also a high amount of lipids, especially in D. tertiolecta and B. braunii. PMID:20350804

Sydney, Eduardo Bittencourt; Sturm, Wilerson; de Carvalho, Julio Cesar; Thomaz-Soccol, Vanete; Larroche, Christian; Pandey, Ashok; Soccol, Carlos Ricardo

2010-08-01

461

Evaluation of NOAA Carbon Tracker Global Carbon Dioxide Products  

NASA Astrophysics Data System (ADS)

Inter-comparison between National Oceanic and Atmospheric Administration Carbon Tracker (NOAACT) CO2 with satellite observations were carried out in this study. The satellite observations used here are mid troposphere CO2 based on Atmosphere Infrared Sounder (AIRS) on board NASA's Aqua and lower troposphere CO2 based on Greenhouse-gas Observing Satellite (GOSAT) of Japanese Aerospace Exploration Agency (JAXA). There exists good agreement between the seasonal cycles as estimated by NOAACT and Satellite observations. The mid troposphere CO2 exhibits distinct annual cycle in the northern hemisphere with positive detrended value during January-June and negative values during July-December. In the southern hemisphere, the annual cycle is less prominent and opposite phase with respect to the northern hemisphere. The lower tropospheric CO2 in both the hemispheres exhibits mixed signature of annual and semi-annual cycle. The amplitudes of the variability are significantly larger in the northern hemisphere than the southern hemisphere. The inter-annual variability of annual growth rates from the NOAACT is comparable with satellite observations however NOAACT could not resolved the spatial patterns of long-term growth rate as observed in the satellite observations.

Nayak, R. K.; Deepthi, E. N.; Dadhwal, V. K.; Rao, K. H.; Dutt, C. B. S.

2014-11-01

462

CARBON DIOXIDE AND OUR OCEAN LEGACY  

E-print Network

. Ocean acidification, as the phenomenon is called, over time will create major negative impacts on corals. Ocean acidification and climate change are both effects of excessive carbon dumping into the atmosphere in 2003, and these numbers are growing every year.3 Ocean acidification is a straightforward consequence

463

Development of Light Weight High Strength Carbon Dioxide Monitor for Sub Orbital Space Craft  

NASA Astrophysics Data System (ADS)

Introduction No commercially material is currently available that can satisfy the performance requirements for Suborbital Sampling of Carbon Dioxide in air .Satellite interrogation is not feasible because of the low altitude, and the altitude is too high for satisfactory performance from balloons. A hybrid material in a light weight canister may be the solution to satisfying the above requirements. An example fiber with carbon dioxide capture agent is wound in an equilateral triangle pattern 3 mm in diameter, and heat bonded to a carbon fiber panel. A layer of polypropylene-methyl cellulose 1 mm thick underlies the carbon fiber. The interior contains a metallized organic polymer heat bonded to this surface. Methodology All component materials were purchased through 3M and Sigma Aldrich Chemical Company. The carbon prepreg pa