Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

NASA Astrophysics Data System (ADS)

Burger, Magdalena; Berger, Sina; Spangenberg, Ines; Blodau, Christian

2016-06-01

Ponds smaller than 10 000 m2 likely account for about one-third of the global lake perimeter. The release of methane (CH4) and carbon dioxide (CO2) from these ponds is often high and significant on the landscape scale. We measured CO2 and CH4 fluxes in a temperate peatland in southern Ontario, Canada, in summer 2014 along a transect from the open water of a small pond (847 m2) towards the surrounding floating mat (5993 m2) and in a peatland reference area. We used a high-frequency closed chamber technique and distinguished between diffusive and ebullitive CH4 fluxes. CH4 fluxes and CH4 bubble frequency increased from a median of 0.14 (0.00 to 0.43) mmol m-2 h-1 and 4 events m-2 h-1 on the open water to a median of 0.80 (0.20 to 14.97) mmol m-2 h-1 and 168 events m-2 h-1 on the floating mat. The mat was a summer hot spot of CH4 emissions. Fluxes were 1 order of magnitude higher than at an adjacent peatland site. During daytime the pond was a net source of CO2 equivalents to the atmosphere amounting to 0.13 (-0.02 to 1.06) g CO2 equivalents m-2 h-1, whereas the adjacent peatland site acted as a sink of -0.78 (-1.54 to 0.29) g CO2 equivalents m-2 h-1. The photosynthetic CO2 uptake on the floating mat did not counterbalance the high CH4 emissions, which turned the floating mat into a strong net source of 0.21 (-0.11 to 2.12) g CO2 equivalents m-2 h-1. This study highlights the large small-scale variability of CH4 fluxes and CH4 bubble frequency at the peatland-pond interface and the importance of the often large ecotone areas surrounding small ponds as a source of greenhouse gases to the atmosphere.

Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

NASA Astrophysics Data System (ADS)

Blodau, Christian; Burger, Magdalena; Berger, Sina; Spangenberg, Ines

2016-04-01

Ponds smaller than 10000 m2 likely account for about one third of the global lake perimeter. The release of methane (CH4) and carbon dioxide (CO2) from these ponds is often high and significant on the landscape scale. We measured CO2 and CH4 fluxes in a temperate peatland in southern Ontario, Canada, in summer 2014 along a transect from the open water of a small pond (847 m2) towards the surrounding floating mat (5993 m2) and in a peatland reference area. We used a high-frequency closed chamber technique and distinguished between diffusive and ebullitive CH4 fluxes. CH4 fluxes and CH4 bubble frequency increased from a median of 0.14 (0.00 to 0.43) mmol m-2 h-1 and 4 events m-2 h-1 on the open water to a median of 0.80 (0.20 to 14.97) mmol m-2 h-1 and 168 events m-2 h-1 on the floating mat. The mat was a summer hot spot of CH4 emissions. Fluxes were one order of magnitude higher than at an adjacent peatland site. During daytime the pond was a net source of CO2 equivalents to the atmosphere amounting to 0.13 (-0.02 to 1.06) g CO2 equivalents m-2 h-1, whereas the adjacent peatland site acted as a sink of -0.78 (-1.54 to 0.29) g CO2 equivalents m-2 h-1. The photosynthetic CO2 uptake on the floating mat did not counterbalance the high CH4 emissions, which turned the floating mat into a strong net source of 0.21 (-0.11 to 2.12) g CO2 equivalents m-2 h-1. This study highlights the large small-scale variability of CH4 fluxes and CH4 bubble frequency at the peatland-pond interface and the importance of the often large ecotone areas surrounding small ponds as a source of greenhouse gases to the atmosphere.

CAFE Standards (released in AEO2010)

EIA Publications

2010-01-01

Pursuant to the Presidents announcement of a National Fuel Efficiency Policy, the National Highway Traffic Safety Administration (NHTSA) and the EPA have promulgated nationally coordinated standards for tailpipe Carbon Dioxide (CO2)-equivalent emissions and fuel economy for light-duty vehicles (LDVs), which includes both passenger cars and light-duty trucks. In the joint rulemaking, the Environmental Protection Agency is enacting CO2-equivalent emissions standards under the Clean Air Act (CAA), and NHTSA is enacting companion Corporate Average Fuel Economy standards under the Energy Policy and Conservation Act, as amended by the Energy Independence and Security Act of 2007.

Application of gas diffusion biocathode in microbial electrosynthesis from carbon dioxide.

PubMed

Bajracharya, Suman; Vanbroekhoven, Karolien; Buisman, Cees J N; Pant, Deepak; Strik, David P B T B

2016-11-01

Microbial catalysis of carbon dioxide (CO 2 ) reduction to multi-carbon compounds at the cathode is a highly attractive application of microbial electrosynthesis (MES). The microbes reduce CO 2 by either taking the electrons or reducing the equivalents produced at the cathode. While using gaseous CO 2 as the carbon source, the biological reduction process depends on the dissolution and mass transfer of CO 2 in the electrolyte. In order to deal with this issue, a gas diffusion electrode (GDE) was investigated by feeding CO 2 through the GDE into the MES reactor for its reduction at the biocathode. A combination of the catalyst layer (porous activated carbon and Teflon binder) and the hydrophobic gas diffusion layer (GDL) creates a three-phase interface at the electrode. So, CO 2 and reducing equivalents will be available to the biocatalyst on the cathode surface. An enriched inoculum consisting of acetogenic bacteria, prepared from an anaerobic sludge, was used as a biocatalyst. The cathode potential was maintained at -1.1 V vs Ag/AgCl to facilitate direct and/or hydrogen-mediated CO 2 reduction. Bioelectrochemical CO 2 reduction mainly produced acetate but also extended the products to ethanol and butyrate. Average acetate production rates of 32 and 61 mg/L/day, respectively, with 20 and 80 % CO 2 gas mixture feed were achieved with 10 cm 2 of GDE. The maximum acetate production rate remained 238 mg/L/day for 20 % CO 2 gas mixture. In conclusion, a gas diffusion biocathode supported bioelectrochemical CO 2 reduction with enhanced mass transfer rate at continuous supply of gaseous CO 2 . Graphical abstract ᅟ.

Line strength measurements and relative isotopic ratio 13C/12C measurements in carbon dioxide using cavity ring down spectroscopy

NASA Astrophysics Data System (ADS)

Kiseleva, M.; Mandon, J.; Persijn, S.; Harren, F. J. M.

2018-01-01

Accurate intensity measurements were performed for several lines of the two main isotopologues of carbon dioxide, using cavity ring down spectroscopy. Absorption spectra of the R52e line at 6112.8902 cm-1 (30014←00001 band) of 12CO2 and the P6e line at 6114.8580 cm-1 (30013←00001 band) of 13CO2 were recorded at pressures between 15 and 50 mbar at 298 K. Line shape analysis shows that Galatry profile, taking into account Dicke narrowing of spectral lines, better describes the measured spectra at all pressures than the Voigt profile. The values of Dicke narrowing parameter for both lines were found to be significantly smaller than those predicted based on the mass diffusion constant. The values of the line strength for R52e line of 12CO2 and P6e line of 13CO2 were determined with an uncertainty of 0.5%. These values were found to be in good agreement with the corresponding data available in literature, in particular with the most recent ab initio calculations. The results of relative isotopic ratio 13CO2/12CO2 measurements are also presented in pure carbon dioxide samples and in 400 μmol/mol carbon dioxide in air samples, using cavity ring down spectroscopy.

Multimodel predictive system for carbon dioxide solubility in saline formation waters.

PubMed

Wang, Zan; Small, Mitchell J; Karamalidis, Athanasios K

2013-02-05

The prediction of carbon dioxide solubility in brine at conditions relevant to carbon sequestration (i.e., high temperature, pressure, and salt concentration (T-P-X)) is crucial when this technology is applied. Eleven mathematical models for predicting CO(2) solubility in brine are compared and considered for inclusion in a multimodel predictive system. Model goodness of fit is evaluated over the temperature range 304-433 K, pressure range 74-500 bar, and salt concentration range 0-7 m (NaCl equivalent), using 173 published CO(2) solubility measurements, particularly selected for those conditions. The performance of each model is assessed using various statistical methods, including the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). Different models emerge as best fits for different subranges of the input conditions. A classification tree is generated using machine learning methods to predict the best-performing model under different T-P-X subranges, allowing development of a multimodel predictive system (MMoPS) that selects and applies the model expected to yield the most accurate CO(2) solubility prediction. Statistical analysis of the MMoPS predictions, including a stratified 5-fold cross validation, shows that MMoPS outperforms each individual model and increases the overall accuracy of CO(2) solubility prediction across the range of T-P-X conditions likely to be encountered in carbon sequestration applications.

Emission reductions from woody biomass waste for energy as an alternative to open burning.

PubMed

Springsteen, Bruce; Christofk, Tom; Eubanks, Steve; Mason, Tad; Clavin, Chris; Storey, Brett

2011-01-01

Woody biomass waste is generated throughout California from forest management, hazardous fuel reduction, and agricultural operations. Open pile burning in the vicinity of generation is frequently the only economic disposal option. A framework is developed to quantify air emissions reductions for projects that alternatively utilize biomass waste as fuel for energy production. A demonstration project was conducted involving the grinding and 97-km one-way transport of 6096 bone-dry metric tons (BDT) of mixed conifer forest slash in the Sierra Nevada foothills for use as fuel in a biomass power cogeneration facility. Compared with the traditional open pile burning method of disposal for the forest harvest slash, utilization of the slash for fuel reduced particulate matter (PM) emissions by 98% (6 kg PM/BDT biomass), nitrogen oxides (NOx) by 54% (1.6 kg NOx/BDT), nonmethane volatile organics (NMOCs) by 99% (4.7 kg NMOCs/BDT), carbon monoxide (CO) by 97% (58 kg CO/BDT), and carbon dioxide equivalents (CO2e) by 17% (0.38 t CO2e/BDT). Emission contributions from biomass processing and transport operations are negligible. CO2e benefits are dependent on the emission characteristics of the displaced marginal electricity supply. Monetization of emissions reductions will assist with fuel sourcing activities and the conduct of biomass energy projects.

Carbon dioxide UV laser-induced fluorescence in high-pressure flames

NASA Astrophysics Data System (ADS)

Bessler, W. G.; Schulz, C.; Lee, T.; Jeffries, J. B.; Hanson, R. K.

2003-07-01

Laser-induced fluorescence (LIF) of carbon dioxide is investigated with excitation between 215 and 255 nm with spectrally resolved detection in 5-40 bar premixed CH 4/O 2/Ar and CH 4/air flat-flames at fuel/air ratios between 0.8 and 1.9. The LIF signal consists of a broad (200-450 nm) continuum with a faint superimposed structure, and this signal is absent in similar H 2/O 2/Ar flames. There is strong evidence this signal arises from CO 2, as the signal variations with excitation wavelength, equivalence ratio and flame temperature all correlate with CO 2 absorption cross-sections. The signal is linear with pressure and laser fluence within the investigated ranges.

New insights into the cellular mechanisms of plant growth at elevated atmospheric carbon dioxide.

PubMed

Gamage, Dananjali; Thompson, Michael; Sutherland, Mark; Hirotsu, Naoki; Makino, Amane; Seneweera, Saman

2018-04-02

Rising atmospheric carbon dioxide concentration ([CO 2 ]) significantly influences plant growth, development and biomass. Increased photosynthesis rate, together with lower stomatal conductance, have been identified as the key factors that stimulate plant growth at elevated [CO 2 ] (e[CO 2 ]). However, variations in photosynthesis and stomatal conductance alone cannot fully explain the dynamic changes in plant growth. Stimulation of photosynthesis at e[CO 2 ] is always associated with post-photosynthetic secondary metabolic processes that include carbon and nitrogen metabolism, cell cycle functions and hormonal regulation. Most studies have focused on photosynthesis and stomatal conductance in response to e[CO 2 ], despite the emerging evidence of e[CO 2 ]'s role in moderating secondary metabolism in plants. In this review, we briefly discuss the effects of e[CO 2 ] on photosynthesis and stomatal conductance and then focus on the changes in other cellular mechanisms and growth processes at e[CO 2 ] in relation to plant growth and development. Finally, knowledge gaps in understanding plant growth responses to e[CO 2 ] have been identified with the aim of improving crop productivity under a CO 2 rich atmosphere. This article is protected by copyright. All rights reserved.

Physiological dead space and arterial carbon dioxide contributions to exercise ventilatory inefficiency in patients with reduced or preserved ejection fraction heart failure.

PubMed

Van Iterson, Erik H; Johnson, Bruce D; Borlaug, Barry A; Olson, Thomas P

2017-12-01

Patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction demonstrate an increased ventilatory equivalent for carbon dioxide (V̇ E /V̇CO 2 ) slope. The physiological correlates of the V̇ E /V̇CO 2 slope remain unclear in the two HF phenotypes. We hypothesized that changes in the physiological dead space to tidal volume ratio (V D /V T ) and arterial CO 2 tension (PaCO 2 ) differentially contribute to the V̇ E /V̇CO 2 slope in HFrEF vs. HFpEF. Adults with HFrEF (n = 32) and HFpEF (n = 27) [mean ± standard deviation (SD) left ventricular ejection fraction: 22 ± 7% and 61 ± 9%, respectively; mean ± SD body mass index: 28 ± 4 kg/m 2 and 33 ± 6 kg/m 2 , respectively; P < 0.01] performed cardiopulmonary exercise testing with breath-by-breath ventilation and gas exchange measurements. PaCO 2 was measured via radial arterial catheterization. We calculated the V̇ E /V̇CO 2 slope via linear regression, and V D /V T  = 1 - [(863 × V̇CO 2 )/(V̇ E  × PaCO 2 )]. Resting V D /V T (0.48 ± 0.08 vs. 0.41 ± 0.11; P = 0.04), but not PaCO 2 (38 ± 5 mmHg vs. 40 ± 3 mmHg; P = 0.21) differed between HFrEF and HFpEF. Peak exercise V D /V T (0.39 ± 0.08 vs. 0.32 ± 0.12; P = 0.02) and PaCO 2 (33 ± 6 mmHg vs. 38 ± 4 mmHg; P < 0.01) differed between HFrEF and HFpEF. The V̇ E /V̇CO 2 slope was higher in HFrEF compared with HFpEF (44 ± 11 vs. 35 ± 8; P < 0.01). Variance associated with the V̇ E /V̇CO 2 slope in HFrEF and HFpEF was explained by peak exercise V D /V T (R 2  = 0.30 and R 2  = 0.50, respectively) and PaCO 2 (R 2  = 0.64 and R 2  = 0.28, respectively), but the relative contributions of each differed (all P < 0.01). Relationships between the V̇ E /V̇CO 2 slope and both V D /V T and PaCO 2 are robust, but differ between HFpEF and HFrEF. Increasing V̇ E /V̇CO 2 slope appears to be strongly explained by mechanisms influential in regulating PaCO 2 in HFrEF, which contrasts with the strong role of increased V D /V T in HFpEF. © 2017 The Authors. European Journal of Heart Failure © 2017 European Society of Cardiology.

21 CFR 868.2480 - Cutaneous carbon dioxide (PcCO2) monitor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cutaneous carbon dioxide (PcCO2) monitor. 868.2480 Section 868.2480 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... (PcCO2) and Oxygen (PcO2) Monitors; Guidance for Industry and FDA.” See § 868.1(e) for the...

Surface Condensation of CO2 onto Kaolinite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaef, Herbert T.; Glezakou, Vassiliki Alexandra; Owen, Antionette T.

2014-02-11

The fundamental adsorption behavior of gaseous and supercritical carbon dioxide (CO2) onto poorly crystalline kaolinite (KGa-2) at conditions relevant to geologic sequestration has been investigated using a quartz crystal microbalance (QCM) and density functional theory (DFT) methods. The QCM data indicated linear adsorption of CO2 (0-0.3 mmol CO2/g KGa-2) onto the kaolinite surface up through the gaseous state (0.186 g/cm3). However in the supercritical region, CO2 adsorption increases dramatically, reaching a peak (0.9-1.0 mmol CO2/g KGa-2) near 0.43 g/cm3, before declining rapidly to surface adsorption values equivalent or below gaseous CO2. This adsorption profile was not observed with He ormore » N2. Comparative density functional studies of CO2 interactions with kaolinite surface models rule out CO2 intercalation and confirm that surface adsorption is favored up to approximately 0.35 g/cm3 of CO2, showing distorted T-shaped CO2-CO2 clustering, typical of supercritical CO2 aggregation over the surface as the density increases. Beyond this point, the adsorption energy gain for any additional CO2 becomes less than the CO2 interaction energy (~0.2 eV) in the supercritical medium resulting in overall desorption of CO2 from the kaolinite surface.« less

Environment and Materials Stewardship | NREL

Science.gov Websites

dioxide equivalent of natural gas in heating facilities and experiments; 105metric tons of carbon dioxide equivalent in fleet and equipment; 15 metric tons of carbon dioxide equivalent in fluorinated gases and refrigerants; and 10 metric tons of carbon dioxide equivalent in dry ice use in laboratories. Scope 2 accounts

Carbon footprint hotspots of prefabricated sandwich panels for hostel construction in Perlis

NASA Astrophysics Data System (ADS)

Razali, Norashikin; Ayob, Afizah; Chandra, Muhammad Erwan Shah; Zaki, Mohd Faiz Mohammad; Ahmad, Abdul Ghapar

2017-10-01

Sustainable design and construction have gained increasing research interest, and reduction of carbon from building construction has become the main focus of environmental strategies in Malaysia. This study uses life cycle assessment and life cycle inventory analysis frameworks to estimate the amount of carbon footprint expressed in carbon dioxide equivalent tons (CO2e) produced by manufacturing prefabricated Industrialized Building System sandwich panels and its installation for a five-story hostel in Perlis, Malaysia. Results show that the carbon footprint hotspots were centered on boiler machine operation and cement with 4.52 and 369.04 tons CO2e, respectively. This finding is due to the extensive energy used for steam heating and high engine rating for the boiler. However, for cement, the carbon footprint hotspots are caused by the large quantity of cement applied in shotcrete mixture and its high extraction and production CO2 emission values. The overall onsite materials generated 96.36% of the total carbon footprint. These carbon footprint hotspot results constitute a necessary base for the Malaysian government in accomplishing an adequate dimensioning of carbon emissions in the building sector.

Life-Cycle Assessment Harmonization and Soil Science Ranking Results on Food-Waste Management Methods.

PubMed

Morris, Jeffrey; Brown, Sally; Cotton, Matthew; Matthews, H Scott

2017-05-16

This study reviewed 147 life cycle studies, with 28 found suitable for harmonizing food waste management methods' climate and energy impacts. A total of 80 scientific soil productivity studies were assessed to rank management method soil benefits. Harmonized climate impacts per kilogram of food waste range from -0.20 kg of carbon dioxide equivalents (CO 2 e) for anaerobic digestion (AD) to 0.38 kg of CO 2 e for landfill gas-to-energy (LFGTE). Aerobic composting (AC) emits -0.10 kg of CO 2 e. In-sink grinding (ISG) via a food-waste disposer and flushing for management with other sewage at a wastewater treatment plant emits 0.10 kg of CO 2 e. Harmonization reduced climate emissions versus nonharmonized averages. Harmonized energy impacts range from -0.32 MJ for ISG to 1.14 MJ for AC. AD at 0.27 MJ and LFGTE at 0.40 MJ fall in between. Rankings based on soil studies show AC first for carbon storage and water conservation, with AD second. AD first for fertilizer replacement, with AC second, and AC and AD tied for first for plant yield increase. ISG ranks third and LFGTE fourth on all four soil-quality and productivity indicators. Suggestions for further research include developing soil benefits measurement methods and resolving inconsistencies in the results between life-cycle assessments and soil science studies.

Chapter 1: Introduction and Summary

USDA-ARS?s Scientific Manuscript database

In 2013, total U.S. greenhouse gas emissions measured 6,673 million metric tons of carbon dioxide equivalents (MMT CO2 eq.), rising 5.9 percent from 1990 estimates. Global concentrations of the three most important long-lived greenhouse gases (GHG) in the atmosphere have increased measurably since t...

Reframing the climate change challenge in light of post-2000 emission trends.

PubMed

Anderson, Kevin; Bows, Alice

2008-11-13

The 2007 Bali conference heard repeated calls for reductions in global greenhouse gas emissions of 50 per cent by 2050 to avoid exceeding the 2 degrees C threshold. While such endpoint targets dominate the policy agenda, they do not, in isolation, have a scientific basis and are likely to lead to dangerously misguided policies. To be scientifically credible, policy must be informed by an understanding of cumulative emissions and associated emission pathways. This analysis considers the implications of the 2 degrees C threshold and a range of post-peak emission reduction rates for global emission pathways and cumulative emission budgets. The paper examines whether empirical estimates of greenhouse gas emissions between 2000 and 2008, a period typically modelled within scenario studies, combined with short-term extrapolations of current emissions trends, significantly constrains the 2000-2100 emission pathways. The paper concludes that it is increasingly unlikely any global agreement will deliver the radical reversal in emission trends required for stabilization at 450 ppmv carbon dioxide equivalent (CO2e). Similarly, the current framing of climate change cannot be reconciled with the rates of mitigation necessary to stabilize at 550 ppmv CO2e and even an optimistic interpretation suggests stabilization much below 650 ppmv CO2e is improbable.

Carbon footprint assessment of Western Australian Groundwater Recycling Scheme

NASA Astrophysics Data System (ADS)

Simms, Andrew; Hamilton, Stacey; Biswas, Wahidul K.

2017-04-01

This research has determined the carbon footprint or the carbon dioxide equivalent (CO2 eq) of potable water production from a groundwater recycling scheme, consisting of the Beenyup wastewater treatment plant, the Beenyup groundwater replenishment trial plant and the Wanneroo groundwater treatment plant in Western Australia, using a life cycle assessment approach. It was found that the scheme produces 1300 tonnes of CO2 eq per gigalitre (GL) of water produced, which is 933 tonnes of CO2 eq higher than the desalination plant at Binningup in Western Australia powered by 100% renewable energy generated electricity. A Monte Carlo Simulation uncertainty analysis calculated a Coefficient of Variation value of 5.4%, thus confirming the accuracy of the simulation. Electricity input accounts for 83% of the carbon dioxide equivalent produced during the production of potable water. The chosen mitigation strategy was to consider the use of renewable energy to generate electricity for carbon intensive groundwater replenishment trial plant. Depending on the local situation, a maximum of 93% and a minimum of 21% greenhouse gas saving from electricity use can be attained at groundwater replenishment trial plant by replacing grid electricity with renewable electricity. In addition, the consideration of vibrational separation (V-Sep) that helps reduce wastes generation and chemical use resulted in a 4.03 tonne of CO2 eq saving per GL of water produced by the plant.

Carbon footprint assessment of Western Australian Groundwater Recycling Scheme.

PubMed

Simms, Andrew; Hamilton, Stacey; Biswas, Wahidul K

2017-04-01

This research has determined the carbon footprint or the carbon dioxide equivalent (CO 2 eq) of potable water production from a groundwater recycling scheme, consisting of the Beenyup wastewater treatment plant, the Beenyup groundwater replenishment trial plant and the Wanneroo groundwater treatment plant in Western Australia, using a life cycle assessment approach. It was found that the scheme produces 1300 tonnes of CO 2 eq per gigalitre (GL) of water produced, which is 933 tonnes of CO 2 eq higher than the desalination plant at Binningup in Western Australia powered by 100% renewable energy generated electricity. A Monte Carlo Simulation uncertainty analysis calculated a Coefficient of Variation value of 5.4%, thus confirming the accuracy of the simulation. Electricity input accounts for 83% of the carbon dioxide equivalent produced during the production of potable water. The chosen mitigation strategy was to consider the use of renewable energy to generate electricity for carbon intensive groundwater replenishment trial plant. Depending on the local situation, a maximum of 93% and a minimum of 21% greenhouse gas saving from electricity use can be attained at groundwater replenishment trial plant by replacing grid electricity with renewable electricity. In addition, the consideration of vibrational separation (V-Sep) that helps reduce wastes generation and chemical use resulted in a 4.03 tonne of CO 2 eq saving per GL of water produced by the plant.

Diurnal variation of CO2, CH4, and N2O emission fluxes continuously monitored in-situ in three environmental habitats in a subtropical estuarine wetland.

PubMed

Yang, Wen-Bin; Yuan, Chung-Shin; Tong, Chuan; Yang, Pin; Yang, Lei; Huang, Bang-Qin

2017-06-15

Wetlands play a crucial role in modulating atmospheric concentrations of greenhouse gases (GHGs) such as carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O). The key factors controlling GHG emission from subtropical estuarine wetlands were investigated in this study, which continuously monitored the uptake/emission of GHGs (CO 2 , CH 4 , and N 2 O) by/from a subtropical estuarine wetland located in the Minjiang estuary in the coastal region of southeastern China. A self-designed floating chamber was used to collect air samples on-site at three environmental habitats (Phragmites australis marsh, mudflats, and river water). The CO 2 , CH 4 , and N 2 O concentrations were then measured using an automated nondispersive infrared analyzer. The magnitudes of the CO 2 and N 2 O emission fluxes at the three habitats were ordered as river water>P. australis>mudflats. P. australis emitted GHGs through photosynthesis and respiration processes. Emissions of CH 4 from P. australis and the mudflats were revealed to be slightly higher than those from the river water. The total GHG emission fluxes at the three environmental habitats were quite similar (4.68-4.78gm -2 h -1 ). However, when the total carbon dioxide equivalent fluxes (CO 2 -e) were considered, the river water was discovered to emit the most CO 2 -e compared with P. australis and the mudflats. Based on its potential to increase global warming, N 2 O was the main contributor to the total GHG emission, with that emitted from the river water being the most considerable. Tidal water carried onto the marsh had its own GHG content and thus has acted as a source or sink of GHGs. However, water quality had a large effect on GHG emissions from the river water whereas the tidal water height did not. Both high salinity and large amounts of sulfates in the wetlands explicitly inhibited the activity of CH 4 -producing bacteria, particularly at nighttime. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamics and Fragmentation of Hydrogen Bonded and van der Waal Clusters upon 26.5 eV Soft X-ray Laser Ionization

NASA Astrophysics Data System (ADS)

Dong, Feng; Heinbuch, Scott; Bernstein, Elliot; Rocca, Jorge

2006-05-01

A desk-top soft x-ray laser is applied to the study of water, methanol, ammonia, sulfur dioxide, carbon dioxide, mixed sulfur dioxide-water, and mixed carbon dioxide-water clusters through single photon ionization time of flight mass spectroscopy. Almost all of the energy above the vertical ionization energy is removed by the ejected electron. Protonated water, methanol, and ammonia clusters dominate the mass spectra for the first three systems. The temperatures of the neutral water and methanol clusters can be estimated. In the case of pure SO2 and CO2, the mass spectra are dominated by (SO2)n^+ and (CO2)n^+ cluster series. When a high or low concentration of SO2/CO2 is mixed with water, we observe (SO2/CO2)nH2O^+ or SO2/CO2(H2O)nH^+ in the mass spectra, respectively. The unimolecular dissociation rate constants for reactions involving loss of one neutral molecule are calculated for the protonated water, methanol, and ammonia clusters as well as for SO2 and CO2 clusters. We find that the 26.5 eV soft x-ray laser is a nearly ideal tool for the study of hydrogen bonded and van der Waals cluster systems and we are currently exploring its usefulness for other more strongly bound systems.

Biofuels from E. Coli: Engineering E. coli as an Electrofuels Chassis for Isooctane Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-07-16

Electrofuels Project: Ginkgo Bioworks is bypassing photosynthesis and engineering E. coli to directly use carbon dioxide (CO2) to produce biofuels. E. coli doesn’t naturally metabolize CO2, but Ginkgo Bioworks is manipulating and incorporating the genes responsible for CO2 metabolism into the microorganism. By genetically modifying E. coli, Ginkgo Bioworks will enhance its rate of CO2 consumption and liquid fuel production. Ginkgo Bioworks is delivering CO2 to E. coli as formic acid, a simple industrial chemical that provides energy and CO2 to the bacterial system.

Can Earthworm "mix up" Soil Carbon Budgets in Temperate Forests Under Elevated Carbon Dioxide?

NASA Astrophysics Data System (ADS)

Sánchez-de León, Y.; González-Meler, M.; Sturchio, N. C.; Wise, D. H.; Norby, R. J.

2008-12-01

The effects of global change on earthworms and their associated feedbacks on soil and ecosystem processes have been largely overlooked. We studied how the responses of a temperate deciduous forest to elevated carbon dioxide atmospheric concentrations (e[CO2]) influence earthworms and the soil processes affected by them. Our objectives were to: i) identify soil layers of active soil mixing under e[CO2] and current carbon dioxide atmospheric concentrations (c[CO2]) using fallout cesium (137Cs), ii) study how e[CO2] affects earthworm populations, iii) understand the relationship between soil mixing and earthworms at our study site, and iv) identify the implications of earthworm-mediated soil mixing for the carbon budget of a temperate forest. To study soil mixing, we measured vertical 137Cs activity in soil cores (0-24 cm depth) collected in replicated e[CO2] and c[CO2] sweetgum (Liquidambar styraciflua) plots (n = 2) in a Free Air CO2 Enrichment (FACE) ecosystem experiment at Oak Ridge National Laboratory. We measured earthworm density and fresh weight in the plots in areas adjacent to where soil cores were taken. Preliminary results on the vertical distribution of 137Cs in the c[CO2] treatments showed that higher 137Cs activity was located from 8-16 cm depth and no 137Cs activity was measured below 20 cm. In contrast, in the e[CO2] treatment, peak 137Cs activity was slightly deeper (10-18 cm), and 137Cs activity was still measured below 22 cm. Mean earthworm density was higher in e[CO2] than c[CO2] treatments (168 m-2 and 87 m-2, respectively; p = 0.046); earthworm fresh weights, however, did not differ significantly between treatments (32 g m-2 and 18 g m-2, respectively; p = 0.182). The 137Cs vertical distribution suggest that soil mixing occurs deeper in e[CO2] than in c[CO2] treatments, which is consistent with higher earthworm densities in e[CO2] than in c[CO2] treatments. Mixing deeper low carbon content soil with shallower high carbon soil may result in a dilution of net carbon inputs in forest soils exposed to e[CO2]. Vertical dilution of new carbon may explain why carbon accrual is detected only near the surface at this FACE site. By identifying the depths of active soil mixing and possible soil mixing mechanisms (e.g. earthworms), accounting of new organic carbon accrual could be more reliably determined for forest soils in response to e[CO2] conditions.

Design of protonation constant measurement apparatus for carbon dioxide capturing solvents

NASA Astrophysics Data System (ADS)

Ma'mun, S.; Amelia, E.; Rahmat, V.; Alwani, D. R.; Kurniawan, D.

2016-11-01

Global warming phenomenon has led to world climate change caused by high concentrations of greenhouse gases (GHG), e.g. carbon dioxide (CO2), in the atmosphere. Carbon dioxide is produced in large amount from coal-fired power plants, iron and steel production, cement production, chemical and petrochemical manufacturing, natural gas purification, and transportation. Carbon dioxide emissions seem to rise from year to year; some efforts to reduce the emissions are, therefore, required. Amine-based absorption could be deployed for post-combustion capture. Some parameters, e.g. mass transfer coefficients and chemical equilibrium constants, are required for a vapor-liquid equilibrium modeling. Protonation constant (pKa), as one of those parameters, could then be measured experimentally. Therefore, an experimental setup to measure pKa of CO2 capturing solvents was designed and validated by measuring the pKa of acetic acid at 30 to 70 °C by a potentiometric titration method. The set up was also used to measure the pKa of MEA at 27 °C. Based on the validation results and due to low vapor pressure of CO2 capturing solvents in general, e.g. alkanolamines, the setup could therefore be used for measuring pKa of the CO2 capturing solvents at temperatures up to 70 °C.

Vehicle emissions of short-lived and long-lived climate forcers: trends and tradeoffs.

PubMed

Edwards, Morgan R; Klemun, Magdalena M; Kim, Hyung Chul; Wallington, Timothy J; Winkler, Sandra L; Tamor, Michael A; Trancik, Jessika E

2017-08-24

Evaluating technology options to mitigate the climate impacts of road transportation can be challenging, particularly when they involve a tradeoff between long-lived emissions (e.g., carbon dioxide) and short-lived emissions (e.g., methane or black carbon). Here we present trends in short- and long-lived emissions for light- and heavy-duty transport globally and in the U.S., EU, and China over the period 2000-2030, and we discuss past and future changes to vehicle technologies to reduce these emissions. We model the tradeoffs between short- and long-lived emission reductions across a range of technology options, life cycle emission intensities, and equivalency metrics. While short-lived vehicle emissions have decreased globally over the past two decades, significant reductions in CO 2 will be required by mid-century to meet climate change mitigation targets. This is true regardless of the time horizon used to compare long- and short-lived emissions. The short-lived emission intensities of some low-CO 2 technologies are higher than others, and thus their suitability for meeting climate targets depends sensitively on the evaluation time horizon. Other technologies offer low intensities of both short-lived emissions and CO 2 .

Electronic structure and reactivity of cobalt oxide dimers and their hexacarbonyl complexes: a density functional study.

PubMed

Uzunova, Ellie L; Mikosch, Hans

2012-03-29

The dimers of cobalt oxide (CoO)(2) with cyclic and open bent structure are studied with the B1LYP density functional; the ordering of states is validated by the CCSD(T) method. The D(2h)-symmetry rhombic dioxide Co(2)O(2) with antiferromagnetically ordered electrons on cobalt centers is the global minimum. The cyclic peroxide Co(2)(O(2)) with side-on-bonded dioxygen in (7)B(2) ground state is separated from the global minimum by an energy gap of 3.15 eV. The dioxide is highly reactive as indicated by the high value of proton affinity and chemical reactivity indices. The four-member ring structures are more stable than those with three-member ring or chain configuration. The thermodynamic stability toward dissociation to CoO increases upon carbonylation, whereas proton affinity and reactivity with release of molecular oxygen also increase. The global minimum of Co(2)O(2)(CO)(6) corresponds to a triplet state (3)A" with oxygen atoms shifted above the molecular plane of the rhombic dioxide Co(2)O(2). The SOMO-LUMO gap in the ground-state carbonylated dioxide is wider, compared to the same gap in the bare dicobalt dioxide. The peroxo-isomer Co(2)(O(2))(CO)(6) retains the planar Co(2)(O(2)) ring and is only stable in a high-spin state (7)A". The carbonylated clusters have increased reactivity in both redox and nucleophilic reactions, as a result of the increased electron density in the Co(2)O(2)-ring area.

Submaximal Exercise Pulmonary Gas Exchange in Left Heart Disease Patients With Different Forms of Pulmonary Hypertension.

PubMed

Taylor, Bryan J; Smetana, Michael R; Frantz, Robert P; Johnson, Bruce D

2015-08-01

We determined whether pulmonary gas exchange indices during submaximal exercise are different in heart failure (HF) patients with combined post- and pre-capillary pulmonary hypertension (PPC-PH) versus HF patients with isolated post-capillary PH (IPC-PH) or no PH. Pulmonary hemodynamics and pulmonary gas exchange were assessed during rest and submaximal exercise in 39 HF patients undergoing right heart catheterization. After hemodynamic evaluation, patients were classified as having no PH (n = 11), IPC-PH (n = 12), or PPC-PH (n = 16). At an equivalent oxygen consumption, end-tidal CO2 (PETCO2) and arterial oxygen saturation (SaO2) were greater in no-PH and IPC-PH versus PPC-PH patients (36.1 ± 3.2 vs. 31.7 ± 4.5 vs. 26.2 ± 4.7 mm Hg and 97 ± 2 vs. 96 ± 3 vs. 91 ± 1%, respectively). Conversely, dead-space ventilation (VD/VT) and the ventilatory equivalent for carbon dioxide (V˙(E)/V˙CO2 ratio) were lower in no-PH and IPC-PH versus PPC-PH patients (0.37 ± 0.05 vs. 0.38 ± 0.04 vs. 0.47 ± 0.03 and 38 ± 5 vs. 42 ± 8 vs. 51 ± 8, respectively). The exercise-induced change in V(D)/V(T), V˙(E)/V˙CO2 ratio, and PETCO2 correlated significantly with the change in mean pulmonary arterial pressure, diastolic pressure difference, and transpulmonary pressure gradient in PPC-PH patients only. Noninvasive pulmonary gas exchange indices during submaximal exercise are different in HF patients with combined post- and pre-capillary PH compared with patients with isolated post-capillary PH or no PH. Copyright © 2015 Elsevier Inc. All rights reserved.

A rational procedure for estimation of greenhouse-gas emissions from municipal wastewater treatment plants.

PubMed

Monteith, Hugh D; Sahely, Halla R; MacLean, Heather L; Bagley, David M

2005-01-01

Municipal wastewater treatment may lead to the emission of greenhouse gases. The current Intergovenmental Panel on Climate Change (Geneva, Switzerland) approach attributes only methane emissions to wastewater treatment, but this approach may overestimate greenhouse gas emissions from the highly aerobic processes primarily used in North America. To better estimate greenhouse gas emissions, a procedure is developed that can be used either with plant-specific data or more general regional data. The procedure was evaluated using full-scale data from 16 Canadian wastewater treatment facilities and then applied to all 10 Canadian provinces. The principal greenhouse gas emitted from municipal wastewater treatment plants was estimated to be carbon dioxide (CO2), with very little methane expected. The emission rates ranged from 0.005 kg CO2-equivalent/m3 treated for primary treatment facilities to 0.26 kg CO2-equivalent/m3 for conventional activated sludge, with anaerobic sludge digestion to over 0.8 kg CO2-equivalent/m3 for extended aeration with aerobic digestion. Increasing the effectiveness of biogas generation and use will decrease the greenhouse gas emissions that may be assigned to the wastewater treatment plant.

Silk industry and carbon footprint mitigation

NASA Astrophysics Data System (ADS)

Giacomin, A. M.; Garcia, J. B., Jr.; Zonatti, W. F.; Silva-Santos, M. C.; Laktim, M. C.; Baruque-Ramos, J.

2017-10-01

Currently there is a concern with issues related to sustainability and more conscious consumption habits. The carbon footprint measures the total amount of greenhouse gas (GHG) emissions produced directly and indirectly by human activities and is usually expressed in tonnes of carbon dioxide (CO2) equivalents. The present study takes into account data collected in scientific literature regarding the carbon footprint, garments produced with silk fiber and the role of mulberry as a CO2 mitigation tool. There is an indication of a positive correlation between silk garments and carbon footprint mitigation when computed the cultivation of mulberry trees in this calculation. A field of them mitigates CO2 equivalents in a proportion of 735 times the weight of the produced silk fiber by the mulberry cultivated area. At the same time, additional researches are needed in order to identify and evaluate methods to advertise this positive correlation in order to contribute to a more sustainable fashion industry.

Carbon sequestration via reaction with basaltic rocks: geochemical modeling and experimental results

USGS Publications Warehouse

Rosenbauer, Robert J.; Thomas, Burt; Bischoff, James L.; Palandri, James

2012-01-01

Basaltic rocks are potential repositories for sequestering carbon dioxide (CO2) because of their capacity for trapping CO2 in carbonate minerals. We carried out a series of thermodynamic equilibrium models and high pressure experiments, reacting basalt with CO2-charged fluids over a range of conditions from 50 to 200 °C at 300 bar. Results indicate basalt has a high reactivity to CO2 acidified brine. Carbon dioxide is taken up from solution at all temperatures from 50 to 200 °C, 300 bar, but the maximum extent and rate of reaction occurs at 100 °C, 300 bar. Reaction path simulations utilizing the geochemical modeling program CHILLER predicted an equilibrium carbonate alteration assemblage of calcite, magnesite, and siderite, but the only secondary carbonate identified in the experiments was a ferroan magnesite. The amount of uptake at 100 °C, 300 bar ranged from 8% by weight for a typical tholeite to 26% for a picrite. The actual amount of CO2 uptake and extent of rock alteration coincides directly with the magnesium content of the rock suggesting that overall reaction extent is controlled by bulk basalt Mg content. In terms of sequestering CO2, an average basaltic MgO content of 8% is equivalent to 2.6 × 108 metric ton CO2/km3 basalt.

Will Transition of Staple Food Strategy in China Really Mitigate Global Climate Change?

NASA Astrophysics Data System (ADS)

Liu, B.; Zhao, D.

2017-12-01

With the increase in agricultural demand, reducing greenhouse gas (GHG) emissions is a vital challenge in mitigating climate change. Potato staple food strategy in China introduced by Ministry of Agriculture in 2015 is to gradually adjust staple food structure, which provides an opportunity to meet with the challenge. Apart from staple food structure, difference on energy, material input, geography, and crop management are essential to determine agriculture's contribution to climate change. In this study, we conduct a life cycle analysis of four staple foods in China, namely rice, wheat, maize, and potato, to develop crop-specific estimates of GHG emissions and GHG intensity by using `Production intensity' (carbon dioxide equivalent emissions per kilocalorie produced), to help us understand potential synergies and frictions between food producing and climate mitigation. Data used in this study is on city / province levels if city level is unavailable in 2015. First, we evaluate GHG reductions due to transition of staple food structure in China. Staple food GHG emissions in China are 546.90 Tg CO2e yr-1 in 2015, with 47.6%, 21.9%, 27.3% and 3.2% from rice, wheat, maize and potato. Mean production intensity of staple food is 0.45 Mg CO2e M kcal-1 in 2015. Maize leads the intensity with 0.77 Mg CO2e M kcal-1, followed by rice (0.49 Mg CO2e M kcal-1), wheat (0.28 Mg CO2e M kcal-1) and potato (0.24 Mg CO2e M kcal-1). After staple food structure adjustment, 25 Tg CO2e yr-1 (4.2%) reduction will be accomplished in 2020 without any crop management improvement. Further reduction (33.3% - 40.4%) could be achieved with crop management improvement. In addition, because of staple food structure switching, native rice production will decline, which might lead to more export from countries with higher production intensity. Estimated emission leakage from rice import is 30.10 Tg CO2e yr-1, exceeds emission reduction in native China. Therefore, potato staple food strategy could meet the demand for food in China, but it increases risk of global climate change.

Interactive effects of seasonal drought and elevated atmospheric carbon dioxide concentration on prokaryotic rhizosphere communities.

PubMed

Drigo, Barbara; Nielsen, Uffe N; Jeffries, Thomas C; Curlevski, Nathalie J A; Singh, Brajesh K; Duursma, Remko A; Anderson, Ian C

2017-08-01

Global change models indicate that rainfall patterns are likely to shift towards more extreme events concurrent with increasing atmospheric carbon dioxide concentration ([CO 2 ]). Both changes in [CO 2 ] and rainfall regime are known to impact above- and belowground communities, but the interactive effects of these global change drivers have not been well explored, particularly belowground. In this experimental study, we examined the effects of elevated [CO 2 ] (ambient + 240 ppm; [eCO 2 ]) and changes in rainfall patterns (seasonal drought) on soil microbial communities associated with forest ecosystems. Our results show that bacterial and archaeal communities are highly resistant to seasonal drought under ambient [CO 2 ]. However, substantial taxa specific responses to seasonal drought were observed at [eCO 2 ], suggesting that [eCO 2 ] compromise the resistance of microbial communities to extreme events. Within the microbial community we were able to identify three types of taxa specific responses to drought: tolerance, resilience and sensitivity that contributed to this pattern. All taxa were tolerant to seasonal drought at [aCO 2 ], whereas resilience and sensitivity to seasonal drought were much greater in [eCO 2 ]. These results provide strong evidence that [eCO 2 ] moderates soil microbial community responses to drought in forests, with potential implications for their long-term persistence and ecosystem functioning. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Commercial Non-Dispersive Infrared Spectroscopy Sensors for Sub-Ambient Carbon Dioxide Detection

NASA Technical Reports Server (NTRS)

Swickrath, Michael J.; Anderson, Molly S.; McMillin, Summer; Broerman, Craig

2013-01-01

Carbon dioxide produced through respiration can accumulate rapidly within closed spaces. If not managed, a crew's respiratory rate increases, headaches and hyperventilation occur, vision and hearing are affected, and cognitive abilities decrease. Consequently, development continues on a number of CO2 removal technologies for human spacecraft and spacesuits. Terrestrially, technology development requires precise performance characterization to qualify promising air revitalization equipment. On-orbit, instrumentation is required to identify and eliminate unsafe conditions. This necessitates accurate in situ CO2 detection. Recursive compensation algorithms were developed for sub-ambient detection of CO2 with commercial off-the-shelf (COTS) non-dispersive infrared (NDIR) sensors. In addition, the source of the exponential loss in accuracy is developed theoretically. The basis of the loss can be explained through thermal, Doppler, and Lorentz broadening effects that arise as a result of the temperature, pressure, and composition of the gas mixture under analysis. The objective was to develop a mathematical routine to compensate COTS CO2 sensors relying on NDIR over pressures, temperatures, and compositions far from calibration conditions. The routine relies on a power-law relationship for the pressure dependency of the sensors along with an equivalent pressure to account for the composition dependency. A Newton-Raphson iterative technique solves for actual carbon dioxide concentration based on the reported concentration. Moreover, first principles routines were established to predict mixed-gas spectra based on sensor specifications (e.g., optical path length). The first principles model can be used to parametrically optimize sensors or sensor arrays across a wide variety of pressures/temperatures/ compositions. In this work, heuristic scaling arguments were utilized to develop reasonable compensation techniques. Experimental results confirmed this approach and provided evidence that composition broadening significantly alters spectra when pressure is reduced. Consequently, a recursive compensation technique was developed with the Newton-Raphson method, which was subsequently verified through experimentation.

Long-term impacts of manure amendments on carbon and greenhouse gas dynamics of rangelands.

PubMed

Owen, Justine J; Parton, William J; Silver, Whendee L

2015-12-01

Livestock manure is applied to rangelands as an organic fertilizer to stimulate forage production, but the long-term impacts of this practice on soil carbon (C) and greenhouse gas (GHG) dynamics are poorly known. We collected soil samples from manured and nonmanured fields on commercial dairies and found that manure amendments increased soil C stocks by 19.0 ± 7.3 Mg C ha(-1) and N stocks by 1.94 ± 0.63 Mg N ha(-1) compared to nonmanured fields (0-20 cm depth). Long-term historical (1700-present) and future (present-2100) impacts of management on soil C and N dynamics, net primary productivity (NPP), and GHG emissions were modeled with DayCent. Modeled total soil C and N stocks increased with the onset of dairying. Nitrous oxide (N2 O) emissions also increased by ~2 kg N2 O-N ha(-1)  yr(-1) . These emissions were proportional to total N additions and offset 75-100% of soil C sequestration. All fields were small net methane (CH4 ) sinks, averaging -4.7 ± 1.2 kg CH4 -C ha(-1)  yr(-1) . Overall, manured fields were net GHG sinks between 1954 and 2011 (-0.74 ± 0.73 Mg CO2 e ha(-1)  yr(-1) , CO2 e are carbon dioxide equivalents), whereas nonmanured fields varied around zero. Future soil C pools stabilized 40-60 years faster in manured fields than nonmanured fields, at which point manured fields were significantly larger sources than nonmanured fields (1.45 ± 0.52 Mg CO2 e ha(-1)  yr(-1) and 0.51 ± 0.60 Mg CO2 e ha(-1)  yr(-1) , respectively). Modeling also revealed a large background loss of soil C from the passive soil pool associated with the shift from perennial to annual grasses, equivalent to 29.4 ± 1.47 Tg CO2 e in California between 1820 and 2011. Manure applications increased NPP and soil C storage, but plant community changes and GHG emissions decreased, and eventually eliminated, the net climate benefit of this practice. © 2015 John Wiley & Sons Ltd.

Estimation of CO2-Equivalent Emission under the Copper Fire Refining Process

NASA Astrophysics Data System (ADS)

Chesnokov, Yu N.; Lisienko, V. G.; Holod, S. I.; Anufriev, V. P.; Lapteva, A. V.

2017-06-01

Non-ferrous metallurgy is one of the most energy-consuming and carbon-emissive sectors of industry. This is due to the fact that the volume of greenhouse gas (GHG) emissions is stipulated by energy consumption. Uralelectromed is a city-forming enterprise of the Verkhnyaya Pyshma. The situation is similar other cities of the old industrial regions of the Russian Federation (Krasnouralsk, Verkhnaya Salda, Karabash, etc.) Verkhnyaya Pyshma has many characteristics of “a clever city”. It can be compared to Hamburg where blister copper is being produced at the center of the city at a copper smelting plant Aurubis. Following the example of such ecologically clean country as Germany and in order to assess how modern energy-efficient low-carbon technologies can provide a favorable habitat, and an acceptable level of carbon footprint, the authors estimated the level of greenhouse gas, i.e., carbon dioxide emission produced by the Uralelectromed. The emission of greenhouse gas -carbon dioxide in the process of fire refining of blister copper has been calculated. The anode melting process consists of several stages where the most important ones are melting of charge, oxidation, and copper melt reduction. Calculations are based on taking into account the mass of burnt carbon of natural gas and the thermal dissociation of fuel oil. It implies that a complete combustion of carbon takes place. The specific value of carbon dioxide emission of the copper refining process is averaged 181 kg CO2 per 1 ton of anode copper.

Atmospheric carbon dioxide changes photochemical activity, soluble sugars and volatile levels in broccoli (Brassica oleracea var. italica).

PubMed

Krumbein, Angelika; Kläring, Hans-Peter; Schonhof, Ilona; Schreiner, Monika

2010-03-24

Atmospheric carbon dioxide (CO(2)) concentration is an environmental factor currently undergoing dramatic changes. The objective of the present study was to determine the effect of doubling the ambient CO(2) concentration on plant photochemistry as measured by photochemical quenching coefficient (qP), soluble sugars and volatiles in broccoli. Elevated CO(2) concentration increased qP values in leaves by up to 100% and 89% in heads, while glucose and sucrose in leaves increased by about 60%. Furthermore, in broccoli heads elevated CO(2) concentration induced approximately a 2-fold increase in concentrations of three fatty acid-derived C(7) aldehydes ((E)-2-heptenal, (E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal), two fatty acid-derived C(5) alcohols (1-penten-3-ol, (Z)-2-pentenol), and two amino acid-derived nitriles (phenyl propanenitrile, 3-methyl butanenitrile). In contrast, concentrations of the sulfur-containing compound 2-ethylthiophene and C(6) alcohol (E)-2-hexenol decreased. Finally, elevated CO(2) concentration increased soluble sugar concentrations due to enhanced photochemical activity in leaves and heads, which may account for the increased synthesis of volatiles.

Green-house gas mitigation capacity of a small scale rural biogas plant calculations for Bangladesh through a general life cycle assessment.

PubMed

Rahman, Khondokar M; Melville, Lynsey; Fulford, David; Huq, Sm Imamul

2017-10-01

Calculations towards determining the greenhouse gas mitigation capacity of a small-scale biogas plant (3.2 m 3 plant) using cow dung in Bangladesh are presented. A general life cycle assessment was used, evaluating key parameters (biogas, methane, construction materials and feedstock demands) to determine the net environmental impact. The global warming potential saving through the use of biogas as a cooking fuel is reduced from 0.40 kg CO 2 equivalent to 0.064 kg CO 2 equivalent per kilogram of dung. Biomethane used for cooking can contribute towards mitigation of global warming. Prior to utilisation of the global warming potential of methane (from 3.2 m 3 biogas plant), the global warming potential is 13 t of carbon dioxide equivalent. This reduced to 2 t as a result of complete combustion of methane. The global warming potential saving of a bioenergy plant across a 20-year life cycle is 217 t of carbon dioxide equivalent, which is 11 t per year. The global warming potential of the resultant digestate is zero and from construction materials is less than 1% of total global warming potential. When the biogas is used as a fuel for cooking, the global warming potential will reduce by 83% compare with the traditional wood biomass cooking system. The total 80 MJ of energy that can be produced from a 3.2 m 3 anaerobic digestion plant would replace 1.9 t of fuel wood or 632 kg of kerosene currently used annually in Bangladesh. The digestate can also be used as a nutrient rich fertiliser substituting more costly inorganic fertilisers, with no global warming potential impact.

Techno-economic analysis of supercritical carbon dioxide power blocks

NASA Astrophysics Data System (ADS)

Meybodi, Mehdi Aghaei; Beath, Andrew; Gwynn-Jones, Stephen; Veeraragavan, Anand; Gurgenci, Hal; Hooman, Kamel

2017-06-01

Developing highly efficient power blocks holds the key to enhancing the cost competitiveness of Concentration Solar Thermal (CST) technologies. Supercritical CO2 (sCO2) Brayton cycles have proved promising in providing equivalent or higher cycle efficiency than supercritical or superheated steam cycles at temperatures and scales relevant for Australian CST applications. In this study, a techno-economic methodology is developed using a stochastic approach to determine the ranges for the cost and performance of different components of central receiver power plants utilizing sCO2 power blocks that are necessary to meet the Australian Solar Thermal Initiative (ASTRI) final LCOE target of 12 c/kWh.

Distribution, origin and prediction of carbon dioxide in petroleum reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thrasher, J.; Fleet, A.J.

1995-08-01

High concentrations of carbon dioxide (CO{sub 2}) in petroleum reservoirs can significantly reduce the value of the discovery, by diluting any hydrocarbons, and by increasing production costs because of the increased likelihood of corrosion and scale formation. Huge volumes of CO{sub 2} have been found, for example in the Indonesian Natuna d-Alpha structure (estimated 240 tcf gas, of which around 70% is CO{sub 2}). This study reviews the possible sources of CO{sub 2} in the petroleum system, and the geological and geochemical data from some CO{sub 2} {open_quotes}polluted{close_quotes} reservoirs, to improve future predictions of the exploration risk of finding significantmore » CO{sub 2}. A number of case studies show that the most common geological circumstances for the occurrence of high concentrations of CO{sub 2} include: carbonates associated with post-trap igneous activity (e.g. Ibleo Platform, Sicily); reservoir close to hot basement (e.g. Cooper-Eromanga Basin, Australia) and deep faults close to traps (e.g. Gulf of Thailand). Less common circumstances for high proportions of CO{sub 2} in gas include: post-trap igneous activity and coals (e.g. Taranaki, New Zealand) and reservoirs associated with pre-oil window coaly kerogen (e.g. Malay Trough), although the volumes of CO{sub 2} generated from kerogen are usually low relative to volumes of hydrocarbons generated from kerogen.« less

A spatially resolved fuel-based inventory of Utah and Colorado oil and natural gas emissions

NASA Astrophysics Data System (ADS)

Gorchov Negron, A.; McDonald, B. C.; De Gouw, J. A.; Frost, G. J.

2015-12-01

A fuel-based approach is presented for estimating emissions from US oil and natural gas production that utilizes state-level fuel surveys of oil and gas engine activity, well-level production data, and emission factors for oil and gas equipment. Emissions of carbon dioxide (CO2) and nitrogen oxides (NOx) are mapped on a 4 km x 4 km horizontal grid for 2013-14 in Utah and Colorado. Emission sources include combustion from exploration (e.g., drilling), production (e.g., heaters, dehydrators, and compressor engines), and natural gas processing plants, which comprise a large fraction of the local combustion activity in oil and gas basins. Fuel-based emission factors of NOx are from the U.S. Environmental Protection Agency, and applied to spatially-resolved maps of CO2 emissions. Preliminary NOx emissions from this study are estimated for the Uintah Basin, Utah, to be ~5300 metric tons of NO2-equivalent in 2013. Our result compares well with an observations-based top-down emissions estimate of NOx derived from a previous study, ~4200 metric tons of NO2-equivalent. By contrast, the 2011 National Emissions Inventory estimates oil and gas emissions of NOx to be ~3 times higher than our study in the Uintah Basin. We intend to expand our fuel-based approach to map combustion-related emissions in other U.S. oil and natural gas basins and compare with additional observational datasets.

A Comparison of Supercritical Carbon Dioxide Power Cycle Configurations with an Emphasis on CSP Applications (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neises, T.; Turchi, C.

2013-09-01

Recent research suggests that an emerging power cycle technology using supercritical carbon dioxide (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus supercritical or superheated steam cycles at temperatures relevant for CSP applications. Preliminary design-point modeling suggests that s-CO2 cycle configurations can be devised that have similar overall efficiency but different temperature and/or pressure characteristics. This paper employs a more detailed heat exchanger model than previous work to compare the recompression and partial cooling cycles, two cycles with high design-point efficiencies, and illustrates the potential advantages of the latter. Integration of themore » cycles into CSP systems is studied, with a focus on sensible heat thermal storage and direct s-CO2 receivers. Results show the partial cooling cycle may offer a larger temperature difference across the primary heat exchanger, thereby potentially reducing heat exchanger cost and improving CSP receiver efficiency.« less

Carbon dioxide in Arctic and subarctic regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1981-03-01

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, themore » 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.« less

Nonthermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with gas-liquid porous metal contractor

USDA-ARS?s Scientific Manuscript database

This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO2) system, with a gas-liquid CO2 contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO2 system at CO2 con...

Comparison of physically- and economically-based CO2-equivalences for methane

NASA Astrophysics Data System (ADS)

Boucher, O.

2012-01-01

There is a controversy on the role methane (and other short-lived species) should play in climate mitigation policies and no consensus on what an optimal methane CO2-equivalence should be. We revisit this question by discussing the relative merits of physically-based (i.e. Global Warming Potential or GWP and Global Temperature change Potential or GTP) and socio-economically-based climate metrics. To this effect we use a simplified Global Damage Potential (GDP) that was introduced by earlier authors and investigate the uncertainties in the methane CO2-equivalence that arise from physical and socio-economic factors. The median value of the methane GDP comes out very close to the widely used methane 100-year GWP because of various compensating effects. However there is a large spread in possible methane CO2-equivalences (1-99% interval: 10.0-42.5; 5-95% interval: 12.5-38.0) that is essentially due to the choice in some socio-economic parameters (i.e. the damage cost function and the discount rate). The methane 100-year GTP falls outside these ranges. It is legitimate to increase the methane CO2-equivalence in the future as global warming unfolds. While changes in biogeochemical cycles and radiative efficiencies cause some small changes to physically-based metrics, a systematic increase in the methane CO2-equivalence can only be achieved by some ad-hoc shortening of the time horizon. In contrast using a convex damage cost function provides a natural increase in the methane CO2-equivalence for the socio-economically-based metrics. We also show that a methane CO2-equivalence based on a pulse emission is sufficient to inform multi-year climate policies and emissions reductions as long as there is some degree of visibility on CO2 prices and CO2-equivalences.

Regenerable sorbent technique for capturing CO.sub.2 using immobilized amine sorbents

DOEpatents

Pennline, Henry W; Hoffman, James S; Gray, McMahan L; Fauth, Daniel J; Resnik, Kevin P

2013-08-06

The disclosure provides a CO.sub.2 absorption method using an amine-based solid sorbent for the removal of carbon dioxide from a gas stream. The method disclosed mitigates the impact of water loading on regeneration by utilizing a conditioner following the steam regeneration process, providing for a water loading on the amine-based solid sorbent following CO.sub.2 absorption substantially equivalent to the moisture loading of the regeneration process. This assists in optimizing the CO.sub.2 removal capacity of the amine-based solid sorbent for a given absorption and regeneration reactor size. Management of the water loading in this manner allows regeneration reactor operation with significant mitigation of energy losses incurred by the necessary desorption of adsorbed water.

Greenhouse gas emissions and the Australian diet--comparing dietary recommendations with average intakes.

PubMed

Hendrie, Gilly A; Ridoutt, Brad G; Wiedmann, Thomas O; Noakes, Manny

2014-01-08

Nutrition guidelines now consider the environmental impact of food choices as well as maintaining health. In Australia there is insufficient data quantifying the environmental impact of diets, limiting our ability to make evidence-based recommendations. This paper used an environmentally extended input-output model of the economy to estimate greenhouse gas emissions (GHGe) for different food sectors. These data were augmented with food intake estimates from the 1995 Australian National Nutrition Survey. The GHGe of the average Australian diet was 14.5 kg carbon dioxide equivalents (CO2e) per person per day. The recommended dietary patterns in the Australian Dietary Guidelines are nutrient rich and have the lowest GHGe (~25% lower than the average diet). Food groups that made the greatest contribution to diet-related GHGe were red meat (8.0 kg CO2e per person per day) and energy-dense, nutrient poor "non-core" foods (3.9 kg CO2e). Non-core foods accounted for 27% of the diet-related emissions. A reduction in non-core foods and consuming the recommended serves of core foods are strategies which may achieve benefits for population health and the environment. These data will enable comparisons between changes in dietary intake and GHGe over time, and provide a reference point for diets which meet population nutrient requirements and have the lowest GHGe.

Greenhouse Gas Emissions and the Australian Diet—Comparing Dietary Recommendations with Average Intakes

PubMed Central

Hendrie, Gilly A.; Ridoutt, Brad G.; Wiedmann, Thomas O.; Noakes, Manny

2014-01-01

Nutrition guidelines now consider the environmental impact of food choices as well as maintaining health. In Australia there is insufficient data quantifying the environmental impact of diets, limiting our ability to make evidence-based recommendations. This paper used an environmentally extended input-output model of the economy to estimate greenhouse gas emissions (GHGe) for different food sectors. These data were augmented with food intake estimates from the 1995 Australian National Nutrition Survey. The GHGe of the average Australian diet was 14.5 kg carbon dioxide equivalents (CO2e) per person per day. The recommended dietary patterns in the Australian Dietary Guidelines are nutrient rich and have the lowest GHGe (~25% lower than the average diet). Food groups that made the greatest contribution to diet-related GHGe were red meat (8.0 kg CO2e per person per day) and energy-dense, nutrient poor “non-core” foods (3.9 kg CO2e). Non-core foods accounted for 27% of the diet-related emissions. A reduction in non-core foods and consuming the recommended serves of core foods are strategies which may achieve benefits for population health and the environment. These data will enable comparisons between changes in dietary intake and GHGe over time, and provide a reference point for diets which meet population nutrient requirements and have the lowest GHGe. PMID:24406846

An Evaluation of the Feasibility of Combining Carbon Dioxide Flooding Technologies with Microbial Enhanced Oil Recovery Technologies in Order To Sequester Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Todd French; Lew Brown; Rafael Hernandez

2009-08-19

The need for more energy as our population grows results in an increase in the amount of CO2 introduced into the atmosphere. The effect of this introduction is currently debated intensely as to the severity of the effect of this. The bjective of this investigation was to determine if the production of more energy (i.e. petroleum) and the sequestration of CO2 could be coupled into one process. Carbon dioxide flooding is a well-established technique that introduces Compressed CO2 into a subsurface oil-bearing formation to aide in liquefying harder to extract petroleum and enhancing its mobility towards the production wells.

Supercritical carbon dioxide process for pasteurization of fruit juices

USDA-ARS?s Scientific Manuscript database

Supercritical carbon dioxide (SCCO2) nonthermal processing inactivates microorganisms in juices using non-toxic and non-reactive CO2. However, data is lacking on the inactivation of E. coli K12 and L. plantarum in apple cider using pilot plant scale SCCO2 equipment. For this study, pasteurized pres...

Optimized Unlike-Pair Interactions for Water-Carbon Dioxide Mixtures described by the SPC/E and EPM2 Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlcek, Lukas; Chialvo, Ariel A; Cole, David

The unlike- pair interaction parameters for the SPC/E- EPM2 models have been optimized to reproduce the mutual solubility of water and carbon dioxide at the conditions of liquid- supercritical fluid phase equilibria. An efficient global optimization of the parameters is achieved through an implementation of the coupling parameter approach, adapted to phase equilibria calculations in the Gibbs ensemble, that explicitly corrects for the over- polarization of the SPC/E water molecule in the non- polar CO2 environments. The resulting H2O- CO2 force field reproduces accurately the available experimental solubilities at the two fluid phases in equilibria as well as the correspondingmore » species tracer diffusion coefficients.« less

Reduction of forest floor respiration by fertilization on both carbon dioxide-enriched and reference 17-year-old loblolly pine stands

Treesearch

John R. Butnor; Kurt H. Johnsen; Ram Oren; Gabriel G. Katul

2003-01-01

Elevated atmospheric carbon dioxide (CO2e) increases soil respiration rates in forest, grassland, agricultural and wetland systems as a result of increased growth, root biomass and enhanced biological activity of soil microorganisms. Less is known about how forest floor fluxes respond to the combined effects of elevated CO...

Greenhouse gas emissions from alternative futures of deforestation and agricultural management in the southern Amazon.

PubMed

Galford, Gillian L; Melillo, Jerry M; Kicklighter, David W; Cronin, Timothy W; Cerri, Carlos E P; Mustard, John F; Cerri, Carlos C

2010-11-16

The Brazilian Amazon is one of the most rapidly developing agricultural areas in the world and represents a potentially large future source of greenhouse gases from land clearing and subsequent agricultural management. In an integrated approach, we estimate the greenhouse gas dynamics of natural ecosystems and agricultural ecosystems after clearing in the context of a future climate. We examine scenarios of deforestation and postclearing land use to estimate the future (2006-2050) impacts on carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) emissions from the agricultural frontier state of Mato Grosso, using a process-based biogeochemistry model, the Terrestrial Ecosystems Model (TEM). We estimate a net emission of greenhouse gases from Mato Grosso, ranging from 2.8 to 15.9 Pg CO(2)-equivalents (CO(2)-e) from 2006 to 2050. Deforestation is the largest source of greenhouse gas emissions over this period, but land uses following clearing account for a substantial portion (24-49%) of the net greenhouse gas budget. Due to land-cover and land-use change, there is a small foregone carbon sequestration of 0.2-0.4 Pg CO(2)-e by natural forests and cerrado between 2006 and 2050. Both deforestation and future land-use management play important roles in the net greenhouse gas emissions of this frontier, suggesting that both should be considered in emissions policies. We find that avoided deforestation remains the best strategy for minimizing future greenhouse gas emissions from Mato Grosso.

Carbon dioxide and water vapor production at rest and during exercise. A report on data collection for the Crew and Thermal Systems Division

NASA Technical Reports Server (NTRS)

Lee, Stuart M. C.; Siconolfi, Steven F.

1994-01-01

The current environmental control device in the shuttle uses lithium hydroxide (LiOH) filter canisters to remove carbon dioxide (CO2) from the cabin air, requiring several bulky filter canisters that can only be used once and must be changed frequently. To alleviate a stowage problem and decrease launch weight, the Crew and Thermal Systems Division (CTSD) at the NASA Johnson Space Center has been researching a system to be used on future shuttle missions. This system uses two beds of solid amine material to absorb CO2 and water, later desorbing them to space vacuum. In this way the air scrubbing medium is regenerable and reusable. To identify the efficacy of this regenerable CO2 removal system (RCRS), CTSD began investigations in the shuttle mockup. The purpose of this investigation was to support the CTSD program by determining mean levels of carbon dioxide and water vapor production in normal, healthy males and females age-matched with the astronaut corps. Subjects' responses were measured at rest and during exercise at intensity levels equivalent to normal shuttle operation activities. The results were used to assess the adjustments made to RCRS and are reported as a reference for future investigations in shuttle environmental control.

Existing agricultural ecosystem in China leads to environmental pollution: an econometric approach.

PubMed

Hongdou, Lei; Shiping, Li; Hao, Li

2018-06-17

Sustainable agriculture ensures food security and prevents starvation. However, the need to meet the increasing food demands of the growing population has led to poor and unsustainable agricultural practices, which promote environmental degradation. Given the contributions of agricultural ecosystems to environmental pollution, we investigated the impact of the agricultural ecosystem on environmental pollution in China using time series data from 1960 to 2014. We employed several methods for econometric analysis including the unit root test, Johansen test of cointegration, Granger causality test, and vector error correction model. Evidence based on the long-run elasticity indicates that a 1% increase in the emissions of carbon dioxide (CO 2 ) equivalent to nitrous oxide from synthetic fertilizers will increase the emissions of CO 2 by 1.52% in the long run. Similarly, a 1% increase in the area of harvested rice paddy, cereal production, biomass of burned crop residues, and agricultural GDP will increase the carbon dioxide emissions by 0.85, 0.63, 0.37, and 0.22%, respectively. The estimated results indicate that there are long-term equilibrium relationships among the selected variables considered for the agricultural ecosystem and carbon dioxide emissions. In particular, we identified bidirectional causal associations between CO 2 emissions, biomass of burned crop residues, and cereal production. Graphical abstract ᅟ.

Mapping rice ecosystem dynamics and greenhouse gas emissions using multiscale imagery and biogeochemical models

NASA Astrophysics Data System (ADS)

Salas, W.; Torbick, N.

2017-12-01

Rice greenhouse gas (GHG) emissions in production hot spots have been mapped using multiscale satellite imagery and a processed-based biogeochemical model. The multiscale Synthetic Aperture Radar (SAR) and optical imagery were co-processed and fed into a machine leanring framework to map paddy attributes that are tuned using field observations and surveys. Geospatial maps of rice extent, crop calendar, hydroperiod, and cropping intensity were then used to parameterize the DeNitrification-DeComposition (DNDC) model to estimate emissions. Results, in the Red River Detla for example, show total methane emissions at 345.4 million kgCH4-C equivalent to 11.5 million tonnes CO2e (carbon dioxide equivalent). We further assessed the role of Alternative Wetting and Drying and the impact on GHG and yield across production hot spots with uncertainty estimates. The approach described in this research provides a framework for using SAR to derive maps of rice and landscape characteristics to drive process models like DNDC. These types of tools and approaches will support the next generation of Monitoring, Reporting, and Verification (MRV) to combat climate change and support ecosystem service markets.

The photodetachment cross-section and threshold energy of negative ions in carbon dioxide

NASA Technical Reports Server (NTRS)

Helmy, E. M.; Woo, S. B.

1974-01-01

Threshold energy and sunlight photodetachment measurements on negative carbon dioxide ions, using a 2.5 kw light pressure xenon lamp, show that: (1) Electron affinity of CO3(+) is larger than 2.7 e.V. and that an isomeric form of CO3(+) is likely an error; (2) The photodetachment cross section of CO3(-) will roughly be like a step function across the range of 4250 to 2500A, having its threshold energy at 4250A; (3) Sunlight photodetachment rate for CO3(-) is probably much smaller than elsewhere reported; and (4) The probability of having photodetached electrons re-attach to form negative ions is less than 1%. Mass identifying drift tube tests confirm that the slower ion is CO3(-), formed through the O(-) + 2CO2 yields CO3(-) + CO2 reaction.

Elevated carbon dioxide reduces emission of herbivore-induced volatiles in Zea mays.

PubMed

Block, Anna; Vaughan, Martha M; Christensen, Shawn A; Alborn, Hans T; Tumlinson, James H

2017-09-01

Terpene volatiles produced by sweet corn (Zea mays) upon infestation with pests such as beet armyworm (Spodoptera exigua) function as part of an indirect defence mechanism by attracting parasitoid wasps; yet little is known about the impact of climate change on this form of plant defence. To investigate how a central component of climate change affects indirect defence, we measured herbivore-induced volatile emissions in plants grown under elevated carbon dioxide (CO 2 ). We found that S. exigua infested or elicitor-treated Z. mays grown at elevated CO 2 had decreased emission of its major sesquiterpene, (E)-β-caryophyllene and two homoterpenes, (3E)-4,8-dimethyl-1,3,7-nonatriene and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene. In contrast, inside the leaves, elicitor-induced (E)-β-caryophyllene hyper-accumulated at elevated CO 2 , while levels of homoterpenes were unaffected. Furthermore, gene expression analysis revealed that the induction of terpene synthase genes following treatment was lower in plants grown at elevated CO 2 . Our data indicate that elevated CO 2 leads both to a repression of volatile synthesis at the transcriptional level and to limitation of volatile release through effects of CO 2 on stomatal conductance. These findings suggest that elevated CO 2 may alter the ability of Z. mays to utilize volatile terpenes to mediate indirect defenses. © 2017 John Wiley & Sons Ltd.

Gadolinia-Doped Ceria Cathodes for Electrolysis of CO2

NASA Technical Reports Server (NTRS)

Adler, Stuart B.

2009-01-01

Gadolinia-doped ceria, or GDC, (Gd(0.4)Ce(0.6)O(2-delta), where the value of delta in this material varies, depending on the temperature and oxygen concentration in the atmosphere in which it is being used) has shown promise as a cathode material for high-temperature electrolysis of carbon dioxide in solid oxide electrolysis cells. The polarization resistance of a GDC electrode is significantly less than that of an otherwise equivalent electrode made of any of several other materials that are now in use or under consideration for use as cathodes for reduction of carbon dioxide. In addition, GDC shows no sign of deterioration under typical temperature and gas-mixture operating conditions of a high-temperature electrolyzer. Electrolysis of CO2 is of interest to NASA as a way of generating O2 from the CO2 in the Martian atmosphere. On Earth, a combination of electrolysis of CO2 and electrolysis of H2O might prove useful as a means of generating synthesis gas (syngas) from the exhaust gas of a coal- or natural-gas-fired power plant, thereby reducing the emission of CO2 into the atmosphere. The syngas a mixture of CO and H2 could be used as a raw material in the manufacture, via the Fisher-Tropsch process, of synthetic fuels, lubrication oils, and other hydrocarbon prod

Mechanisms of Inactivation of Dry Escherichia coli by High-Pressure Carbon Dioxide

PubMed Central

Chen, Yuan Yao; Temelli, Feral

2017-01-01

ABSTRACT High-pressure carbon dioxide processing is a promising technology for nonthermal food preservation. However, few studies have determined the lethality of high-pressure CO2 on dry bacterial cells, and the mechanism of inactivation remains unknown. This study explored the mechanisms of inactivation by using Escherichia coli AW1.7 and mutant strains differing in heat and acid resistance, in membrane composition based on disruption of the locus of heat resistance, and in genes coding for glutamate decarboxylases and cyclopropane fatty acid synthase. The levels of lethality of treatments with liquid, gaseous, and supercritical CO2 were compared. The cell counts of E. coli AW1.7 and mutants with a water activity (aW) of 1.0 were reduced by more than 3 log10 (CFU/ml) after supercritical CO2 treatment at 35°C for 15 min; increasing the pressure generally enhanced inactivation, except for E. coli AW1.7 ΔgadAB. E. coli AW1.7 Δcfa was more susceptible than E. coli AW1.7 after treatment at 10 and 40 MPa; other mutations did not affect survival. Dry cells of E. coli were resistant to treatments with supercritical and liquid CO2 at any temperature. Treatments with gaseous CO2 at 65°C were more bactericidal than those with supercritical CO2 or treatments at 65°C only. Remarkably, E. coli AW1.7 was more susceptible than E. coli AW1.7 Δcfa when subjected to the gaseous CO2 treatment. This study identified CO2-induced membrane fluidization and permeabilization as causes of supercritical mediated microbial inactivation, and diffusivity was a dominant factor for gaseous CO2. IMPORTANCE The safety of dry foods is of increasing concern for public health. Desiccated microorganisms, including pathogens, remain viable over long periods of storage and generally tolerate environmental insults that are lethal to the same organisms at high water activity. This study explored the use of high-pressure carbon dioxide to determine its lethality for dried Escherichia coli and to provide insight into the mechanisms of inactivation. The lethality of high-pressure CO2 and the mechanisms of CO2-mediated inactivation of dry E. coli depended on the physical state of CO2. Liquid and supercritical CO2 were ineffective in reducing the cell counts of dry E. coli isolates, and the effectiveness of gaseous CO2 was related to the diffusivity of CO2. Results provide a novel and alternative method for the food industry to enhance the safety of low aW products. PMID:28283526

Mechanisms of Inactivation of Dry Escherichia coli by High-Pressure Carbon Dioxide.

PubMed

Chen, Yuan Yao; Temelli, Feral; Gänzle, Michael G

2017-05-15

High-pressure carbon dioxide processing is a promising technology for nonthermal food preservation. However, few studies have determined the lethality of high-pressure CO 2 on dry bacterial cells, and the mechanism of inactivation remains unknown. This study explored the mechanisms of inactivation by using Escherichia coli AW1.7 and mutant strains differing in heat and acid resistance, in membrane composition based on disruption of the locus of heat resistance, and in genes coding for glutamate decarboxylases and cyclopropane fatty acid synthase. The levels of lethality of treatments with liquid, gaseous, and supercritical CO 2 were compared. The cell counts of E. coli AW1.7 and mutants with a water activity (a W ) of 1.0 were reduced by more than 3 log 10 (CFU/ml) after supercritical CO 2 treatment at 35°C for 15 min; increasing the pressure generally enhanced inactivation, except for E. coli AW1.7 Δ gadAB E. coli AW1.7 Δ cfa was more susceptible than E. coli AW1.7 after treatment at 10 and 40 MPa; other mutations did not affect survival. Dry cells of E. coli were resistant to treatments with supercritical and liquid CO 2 at any temperature. Treatments with gaseous CO 2 at 65°C were more bactericidal than those with supercritical CO 2 or treatments at 65°C only. Remarkably, E. coli AW1.7 was more susceptible than E. coli AW1.7 Δ cfa when subjected to the gaseous CO 2 treatment. This study identified CO 2 -induced membrane fluidization and permeabilization as causes of supercritical mediated microbial inactivation, and diffusivity was a dominant factor for gaseous CO 2 IMPORTANCE The safety of dry foods is of increasing concern for public health. Desiccated microorganisms, including pathogens, remain viable over long periods of storage and generally tolerate environmental insults that are lethal to the same organisms at high water activity. This study explored the use of high-pressure carbon dioxide to determine its lethality for dried Escherichia coli and to provide insight into the mechanisms of inactivation. The lethality of high-pressure CO 2 and the mechanisms of CO 2 -mediated inactivation of dry E. coli depended on the physical state of CO 2 Liquid and supercritical CO 2 were ineffective in reducing the cell counts of dry E. coli isolates, and the effectiveness of gaseous CO 2 was related to the diffusivity of CO 2 Results provide a novel and alternative method for the food industry to enhance the safety of low a W products. Copyright © 2017 American Society for Microbiology.

Production and characterization of biodiesel from carbon dioxide concentrating chemolithotrophic bacteria, Serratia sp. ISTD04.

PubMed

Bharti, Randhir K; Srivastava, Shaili; Thakur, Indu Shekhar

2014-02-01

A chemolithotrophic bacterium, Serratia sp. ISTD04, enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was evaluated for potential of carbon dioxide (CO2) sequestration and biofuel production. CO2 sequestration efficiency of the bacterium was determined by enzymatic activity of carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Further, Western blot analysis confirmed presence of RuBisCO. The bacterium produced 0.487 and 0.647mgmg(-1) per unit cell dry weight of hydrocarbons and lipids respectively. The hydrocarbons were within the range of C13-C24 making it equivalent to light oil. GC-MS analysis of lipids produced by the bacterium indicated presence of C15-C20 organic compounds that made it potential source of biodiesel after transesterification. GC-MS, FTIR and NMR spectroscopic characterization of the fatty acid methyl esters revealed the presence of 55% and 45% of unsaturated and saturated organic compounds respectively, thus making it a balanced biodiesel composition. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of physically- and economically-based CO2-equivalences for methane

NASA Astrophysics Data System (ADS)

Boucher, O.

2012-05-01

There is a controversy on the role methane (and other short-lived species) should play in climate mitigation policies, and there is no consensus on what an optimal methane CO2-equivalence should be. We revisit this question by discussing some aspects of physically-based (i.e. global- warming potential or GWP and global temperature change potential or GTP) and socio-economically-based climate metrics. To this effect we use a simplified global damage potential (GDP) that was introduced by earlier authors and investigate the uncertainties in the methane CO2-equivalence that arise from physical and socio-economic factors. The median value of the methane GDP comes out very close to the widely used methane 100-yr GWP because of various compensating effects. However, there is a large spread in possible methane CO2-equivalences from this metric (1-99% interval: 10.0-42.5; 5-95% interval: 12.5-38.0) that is essentially due to the choice in some socio-economic parameters (i.e. the damage cost function and the discount rate). The main factor differentiating the methane 100-yr GTP from the methane 100-yr GWP and the GDP is the fact that the former metric is an end-point metric, whereas the latter are cumulative metrics. There is some rationale for an increase in the methane CO2-equivalence in the future as global warming unfolds, as implied by a convex damage function in the case of the GDP metric. We also show that a methane CO2-equivalence based on a pulse emission is sufficient to inform multi-year climate policies and emissions reductions, as long as there is enough visibility on CO2 prices and CO2-equivalences for the stakeholders.

Optimization of Supercritical Carbon Dioxide Extraction of Eucommia ulmoides Seed Oil and Quality Evaluation of the Oil.

PubMed

Zhang, Zhen-Shan; Liu, Yu-Lan; Che, Li-Ming

2018-03-01

Supercritical carbon dioxide extraction (SC-CO 2 ) technology was used to extract oil from Eucommia ulmoides seed. The optimum conditions and significant parameters in SC-CO 2 were obtained using response surface methodology (RSM). The qualities of the extracted oil were evaluated by physicochemical properties, fatty acid composition, vitamin E composition. It was found that the optimum extraction parameters were at pressure of 37 MPa, temperature of 40°C, extraction time of 125 min and CO 2 flow rate of 2.6 SL/min. Pressure, temperature and time were identified as significant parameter effecting on extraction yield. The importance of evaluated parameters decreased in the order of pressure > extraction time > temperature > CO 2 flow rate. GC analysis indicated that E. ulmoides seed oil contained about 61% of linolenic acid and its fatty acid composition was similar with that of flaxseed oil and perilla oil. The content and composition of vitamin E was determined using HPLC. The E. ulmoides seed oil was rich in vitamin E (190.72 mg/100 g), the predominant vitamin E isomers were γ- tocopherol and δ- tocopherol, which accounted for 70.87% and 24.81% of the total vitamin E, respectively. The high yield and good physicochemical properties of extracted oil support the notion that SC-CO 2 technology is an effective technique for extracting oil from E. ulmoides seed.

Hyperthermic-induced hyperventilation and associated respiratory alkalosis in humans.

PubMed

Abbiss, Chris R; Nosaka, Kazunori; Laursen, Paul B

2007-05-01

The purpose of this study was to determine if increased environmental heat leads to hyperthermic-induced hypocapnia and associated alkalosis during prolonged self-paced cycling. Nine male cyclists completed three 100 km stochastic time trials in hot (34 degrees C), neutral (22 degrees C) and cold (10 degrees C) environments. Intermittent measurements of rectal and skin temperature, expired gases, blood pH, PaCO(2), PaO(2), and bicarbonate were made throughout. Rectal temperature increased significantly throughout all trials (P < 0.001) and was significantly correlated with increases in the ventilatory equivalent for carbon dioxide (Ve/ VCo2; r = 0.77; P < 0.001) and blood pH (r = 0.69; P < 0.05). Rectal temperature was also negatively correlated with a reduction in PaCO(2) (r = -0.80; P < 0.001). PaO(2) and bicarbonate concentration remained constant throughout all trials. This study has shown that prolonged self-paced cycling is associated with a hyperthermic-induced hyperventilation, causing a decrease in arterialized carbon dioxide tension and consequential respiratory alkalosis.

CO2-induced alterations in plant nitrate utilization and root exudation stimulate N2O emissions

USDA-ARS?s Scientific Manuscript database

Atmospheric carbon dioxide enrichment (eCO2) often increases soil nitrous oxide (N2O) emissions, which has been largely attributed to increased denitrification induced by CO2-enhancement of soil labile C and moisture. However, the origin of the nitrogen (N) remains unexplained. Emerging evidence sug...

Technology advancement of the electrochemical CO2 concentrating process

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Heppner, D. B.; Hallick, T. M.; Woods, R. R.

1979-01-01

Two multicell, liquid-cooled, advanced electrochemical depolarized carbon dioxide concentrator modules were fabricated. The cells utilized advanced, lightweight, plated anode current collectors, internal liquid cooling and lightweight cell frames. Both were designed to meet the carbon dioxide removal requirements of one-person, i.e., 1.0 kg/d (2.2 lb/d).

The Contribution to Arctic Climate Change from Countries in the Arctic Council

NASA Astrophysics Data System (ADS)

Schultz, T.; MacCracken, M. C.

2013-12-01

The conventional accounting frameworks for greenhouse gas (GHG) emissions used today, established under the Kyoto Protocol 25 years ago, exclude short lived climate pollutants (SLCPs), and do not include regional effects on the climate. However, advances in climate science now suggest that mitigation of SLCPs can reduce up to 50% of global warming by 2050. It has also become apparent that regions such as the Arctic have experienced a much greater degree of anthropogenic warming than the globe as a whole, and that efforts to slow this warming could benefit the larger effort to slow climate change around the globe. A draft standard for life cycle assessment (LCA), LEO-SCS-002, being developed under the American National Standards Institute process, has integrated the most recent climate science into a unified framework to account for emissions of all radiatively significant GHGs and SLCPs. This framework recognizes four distinct impacts to the oceans and climate caused by GHGs and SLCPs: Global Climate Change; Arctic Climate Change; Ocean Acidification; and Ocean Warming. The accounting for Arctic Climate Change, the subject of this poster, is based upon the Absolute Regional Temperature Potential, which considers the incremental change to the Arctic surface temperature resulting from an emission of a GHG or SLCP. Results are evaluated using units of mass of carbon dioxide equivalent (CO2e), which can be used by a broad array of stakeholders, including scientists, consumers, policy makers, and NGOs. This poster considers the contribution to Arctic Climate Change from emissions of GHGs and SLCPs from the eight member countries of the Arctic Council; the United States, Canada, Russia, Denmark, Finland, Iceland, Norway, and Sweden. Of this group of countries, the United States was the largest contributor to Arctic Climate Change in 2011, emitting 9600 MMT CO2e. This includes a gross warming of 11200 MMT CO2e (caused by GHGs, black and brown carbon, and warming effects of nitrogen oxides), which is offset by -1600 MMT CO2e in cooling (caused by organic carbon aerosols, sulfate aerosols, and cooling effects of nitrogen oxides). Russia, Canada, and all the Nordic Countries emitted 5300, 1100, and 300 MMT CO2e (net) in 2011, respectively. Emissions of carbon dioxide, methane, and carbonaceous aerosols were the largest contributors overall, though the significance of each varied by country. This work incorporates the research and methods developed by D. Shindell, G. Faluvegi, M. Jacobson, A. Hu, V. Ramanathan, and T. Bond.

Net emissions of CH4 and CO2 in Alaska: Implications for the region's greenhouse gas budget

USGS Publications Warehouse

Zhuang, Q.; Melillo, J.M.; McGuire, A.D.; Kicklighter, D.W.; Prinn, R.G.; Steudler, P.A.; Felzer, B.S.; Hu, S.

2007-01-01

We used a biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to study the net methane (CH4) fluxes between Alaskan ecosystems and the atmosphere. We estimated that the current net emissions of CH4 (emissions minus consumption) from Alaskan soils are ???3 Tg CH 4/yr. Wet tundra ecosystems are responsible for 75% of the region's net emissions, while dry tundra and upland boreal forests are responsible for 50% and 45% of total consumption over the region, respectively. In response to climate change over the 21st century, our simulations indicated that CH 4 emissions from wet soils would be enhanced more than consumption by dry soils of tundra and boreal forests. As a consequence, we projected that net CH4 emissions will almost double by the end of the century in response to high-latitude warming and associated climate changes. When we placed these CH4 emissions in the context of the projected carbon budget (carbon dioxide [CO2] and CH4) for Alaska at the end of the 21st century, we estimated that Alaska will be a net source of greenhouse gases to the atmosphere of 69 Tg CO2 equivalents/yr, that is, a balance between net methane emissions of 131 Tg CO2 equivalents/yr and carbon sequestration of 17 Tg C/yr (62 Tg CO2 equivalents/yr). ?? 2007 by the Ecological Society of America.

21 CFR 868.2480 - Cutaneous carbon dioxide (PcCO 2) monitor.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cutaneous carbon dioxide (PcCO 2) monitor. 868... dioxide (PcCO 2) monitor. (a) Identification. A cutaneous carbon dioxide (PcCO2) monitor is a noninvasive... relative changes in a hemodynamically stable patient's cutaneous carbon dioxide tension as an adjunct to...

21 CFR 868.2480 - Cutaneous carbon dioxide (PcCO 2) monitor.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cutaneous carbon dioxide (PcCO 2) monitor. 868... dioxide (PcCO 2) monitor. (a) Identification. A cutaneous carbon dioxide (PcCO2) monitor is a noninvasive... relative changes in a hemodynamically stable patient's cutaneous carbon dioxide tension as an adjunct to...

CO2-laser-assisted microsurgical anastomosis in reconstructive microsurgery

NASA Astrophysics Data System (ADS)

Kiyoshige, Yoshiro

1996-01-01

Since 1984, the author used a low output carbon dioxide laser for microsurgical anastomoses in the experimental investigation with rats. The series of experiments demonstrates the following characteristics, in comparison with conventional microsurgical anastomoses: ease in technique; less time consumption; equivalency of patency rate and bursting pressure; but only about 50% of the tensile strength of manual suture anastomosis. These findings suggested that low output carbon dioxide laser has the potential for clinical application. Then this technique has been applied in six clinical cases with digital replantations and free vascularized flap since 1988. The procedure offers increased safety and speed in reconstructive microsurgery.

Carbonic acid as a reserve of carbon dioxide on icy moons: The formation of carbon dioxide (CO{sub 2}) in a polar environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni, E-mail: brantmj@hawaii.edu

Carbon dioxide (CO{sub 2}) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ν{sub 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 CO{sub 2} 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 amore » rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H{sub 2}O)-carbon dioxide (CO{sub 2}) (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 ν{sub 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.« less

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions

PubMed Central

Omae, Iwao

2016-01-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO2 and H2, and hydrogen production from the formic acid. This formic acid can be a useful agent for H2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g., dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO2. 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N,N-dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds. PMID:28503084

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions.

PubMed

Omae, Iwao

2016-04-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO 2 and H 2 , and hydrogen production from the formic acid. This formic acid can be a useful agent for H 2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g. , dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO 2 . 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N , N -dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds.

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elgowainy, Amgad; Han, Jeongwoo; Ward, Jacob

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ~450 gCO2e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H2 FCEVs, andmore » BEVs range from 300-350 gCO2e/mi. Future vehicle efficiency gains are expected to reduce emissions to ~350 gCO2/mi for ICEVs and ~250 gCO2e/mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.« less

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elgowainy, Amgad; Han, Jeongwoo; Ward, Jacob

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025–2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ~450 gCO2e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H2 FCEVs, andmore » BEVs range from 300–350 gCO2e/mi. Future vehicle efficiency gains are expected to reduce emissions to ~350 gCO2/mi for ICEVs and ~250 gCO2e/mi for HEVs, PHEVs, FCEVs and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25–$1.00/mi depending on timeframe and vehicle-fuel technology. In all cases, vehicle cost represents the major (60–90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.« less

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment.

PubMed

Elgowainy, Amgad; Han, Jeongwoo; Ward, Jacob; Joseck, Fred; Gohlke, David; Lindauer, Alicia; Ramsden, Todd; Biddy, Mary; Alexander, Mark; Barnhart, Steven; Sutherland, Ian; Verduzco, Laura; Wallington, Timothy J

2018-02-20

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ∼450 gCO 2 e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H 2 FCEVs, and BEVs range from 300-350 gCO 2 e/mi. Future vehicle efficiency gains are expected to reduce emissions to ∼350 gCO 2 /mi for ICEVs and ∼250 gCO 2e /mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

Carbonic Acid by Ion Implantation in Water_solarCarbon Dioxide Ice Mixtures

NASA Astrophysics Data System (ADS)

Brucato, J. R.; Palumbo, M. E.; Strazzulla, G.

1997-01-01

We present the results of experiments performed by keV ion (He and H) bombardment of frozen mixtures of H 2O:CO 2and of pure CO 2ice. Using keV He ions we confirm the already reported measurement of carbonic acid (H 2CO 3) production in an ice mixture of frozen water and carbon dioxide (1:1) after irradiation by 0.7 MeV H ions (Moore, M. H., and R. K. Khanna 1991. Spectrochim. Acta47, 255-262; Moore, M. H., R. K. Khanna, and B. Donn 1991. J. Geophys. Res. E96(2), 17,541-17,545.). Contrary to a previous report (Pirronello, V., W. L. Brown, L. J. Lanzerotti, K. J. Marcantonio, and E. H. Simmons 1982. Astrophys. J.262, 636-640.), formaldehyde (H 2CO), if any, is not a major product. Implantation with hydrogen ions demonstrates that carbonic acid is formed even if the irradiated target is pure CO 2; i.e., the implanted ion is incorporated into the target and forms new bonds. Some possible astrophysical applications on Solar System objects or (pre-solar) interstellar grains are discussed.

The relationships between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

NASA Astrophysics Data System (ADS)

Jamali, H.; Livesley, S. J.; Hutley, L. B.; Fest, B.; Arndt, S. K.

2013-04-01

We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e) basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past) would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but these relationships vary greatly among termite species. Thus, there is no generic relationship that will allow for the accurate prediction of CH4 fluxes from termite mounds of all species, but given the data limitations, the above methods may still be used with caution.

Nutritional, Economic, and Environmental Costs of Milk Waste in a Classroom School Breakfast Program.

PubMed

Blondin, Stacy A; Cash, Sean B; Goldberg, Jeanne P; Griffin, Timothy S; Economos, Christina D

2017-04-01

To measure fluid milk waste in a US School Breakfast in the Classroom Program and estimate its nutritional, economic, and environmental effects. Fluid milk waste was directly measured on 60 elementary school classroom days in a medium-sized, urban district. The US Department of Agriculture nutrition database, district cost data, and carbon dioxide equivalent (CO 2 e) emissions and water footprint estimates for fluid milk were used to calculate the associated nutritional, economic, and environmental costs. Of the total milk offered to School Breakfast Program participants, 45% was wasted. A considerably smaller portion of served milk was wasted (26%). The amount of milk wasted translated into 27% of vitamin D and 41% of calcium required of School Breakfast Program meals. The economic and environmental costs amounted to an estimated $274 782 (16% of the district's total annual School Breakfast Program food expenditures), 644 893 kilograms of CO 2 e, and 192 260 155 liters of water over the school year in the district. These substantial effects of milk waste undermine the School Breakfast Program's capacity to ensure short- and long-term food security and federal food waste reduction targets. Interventions that reduce waste are urgently needed.

TES/Aura L2 Carbon Dioxide (CO2) Nadir V6 (TL2CO2N)

Atmospheric Science Data Center

2018-01-18

TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.2 x 8.5 km nadir ... Contact User Services Parameters:  Carbon Dioxide Legacy:  Retired data product , click here ...

End-Tidal Carbon Dioxide Measurement during Pediatric Polysomnography: Signal Quality, Association with Apnea Severity, and Prediction of Neurobehavioral Outcomes.

PubMed

Paruthi, Shalini; Rosen, Carol L; Wang, Rui; Weng, Jia; Marcus, Carole L; Chervin, Ronald D; Stanley, Jeffrey J; Katz, Eliot S; Amin, Raouf; Redline, Susan

2015-11-01

To identify the role of end-tidal carbon dioxide (EtCO2) monitoring during polysomnography in evaluation of children with obstructive sleep apnea syndrome (OSAS), including the correlation of EtCO2 with other measures of OSAS and prediction of changes in cognition and behavior after adenotonsillectomy. Analysis of screening and endpoint data from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study comparing early adenotonsillectomy (eAT) to watchful waiting/supportive care (WWSC) in children with OSAS. Multisite clinical referral settings. Children, ages 5.0 to 9.9 y with suspected sleep apnea. eAT or WWSC. Quality EtCO2 waveforms were present for ≥ 75% of total sleep time (TST) in 876 of 960 (91.3%) screening polysomnograms. Among the 322 children who were randomized, 55 (17%) met pediatric criteria for hypoventilation. The mean TST with EtCO2 > 50 mmHg was modestly correlated with apnea-hypopnea index (AHI) (r = 0.33; P < 0.0001) and with oxygen saturation ≤ 92% (r = 0.26; P < 0.0001). After adjusting for AHI, obesity, and other factors, EtCO2 > 50 mmHg was higher in African American children than others. The TST with EtCO2 > 50 mmHg decreased significantly more after eAT than WWSC. In adjusted analyses, baseline TST with EtCO2 > 50 mmHg did not predict postoperative changes in cognitive and behavioral measurements. Among children with suspected obstructive sleep apnea syndrome, overnight end-tidal carbon dioxide (EtCO2) levels are weakly to modestly correlated with other polysomnographic indices and therefore provide independent information on hypoventilation. EtCO2 levels improve with adenotonsillectomy but are not as responsive as AHI and do not provide independent prediction of cognitive or behavioral response to surgery. Childhood Adenotonsillectomy Study for Children with OSAS (CHAT). ClinicalTrials.gov Identifier #NCT00560859. © 2015 Associated Professional Sleep Societies, LLC.

Electrochemical capture and release of carbon dioxide

DOE PAGES

Rheinhardt, Joseph H.; Singh, Poonam; Tarakeshwar, Pilarisetty; ...

2017-01-18

Understanding the chemistry of carbon dioxide is key to affecting changes in atmospheric concentrations. One area of intense interest is CO 2 capture in chemically reversible cycles relevant to carbon capture technologies. Most CO 2 capture methods involve thermal cycles in which a nucleophilic agent captures CO 2 from impure gas streams (e.g., flue gas), followed by a thermal process in which pure CO 2 is released. Several reviews have detailed progress in these approaches. A less explored strategy uses electrochemical cycles to capture CO 2 and release it in pure form. These cycles typically rely on electrochemical generation ofmore » nucleophiles that attack CO 2 at the electrophilic carbon atom, forming a CO 2 adduct. Then, CO 2 is released in pure form via a subsequent electrochemical step. In this Perspective, we describe electrochemical cycles for CO 2 capture and release, emphasizing electrogenerated nucleophiles. As a result, we also discuss some advantages and disadvantages inherent in this general approach.« less

The Effect of Elevated CO2 and O3 on Soil Nitrogen Inputs and Losses in a Soybean Agroecosystem in Illinois

USDA-ARS?s Scientific Manuscript database

It has been found that elevated atmospheric carbon dioxide (eCO2) and tropospheric ozone (eO3) affect belowground microbial processes, including N transformations, through plant-mediated changes. Conversely, changes in soil organic carbon sequestration and plant biomass production are constrained by...

TES/Aura L2 Carbon Dioxide (CO2) Nadir V6 (TL2CO2NS)

Atmospheric Science Data Center

2018-01-22

TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 x 8.5 km nadir ... Contact ASDC User Services Parameters:  Carbon Dioxide Legacy:  Retired data product , click here ...

Investigation of CO2 release pressures in pipeline cracks

NASA Astrophysics Data System (ADS)

Gorenz, Paul; Herzog, Nicoleta; Egbers, Christoph

2013-04-01

The CCS (Carbon Capture and Storage) technology can prevent or reduce the emissions of carbon dioxide. The main idea of this technology is the segregation and collection of CO2 from facilities with a high emission of that greenhouse gas, i.e. power plants which burn fossil fuels. To segregate CO2 from the exhaust gas the power plant must be upgraded. Up to now there are three possible procedures to segregate the carbon dioxide with different advantages and disadvantages. After segregation the carbon dioxide will be transported by pipeline to a subsurface storage location. As CO2 is at normal conditions (1013,25 Pa; 20 °C) in a gaseous phase state it must be set under high pressure to enter denser phase states to make a more efficient pipeline transport possible. Normally the carbon dioxide is set into the liquid or supercritical phase state by compressor stations which compress the gas up to 15 MPa. The pressure drop makes booster stations along the pipeline necessary which keep the CO2 in a dens phase state. Depending on the compression pressure CO2 can be transported over 300km without any booster station. The goal of this work is the investigation of release pressures in pipeline cracks. The high pressurised pipeline system consists of different parts with different failure probabilities. In most cases corrosion or obsolescence is the reason for pipeline damages. In case of a crack CO2 will escape from the pipeline and disperse into the atmosphere. Due to its nature CO2 can remain unattended for a long time. There are some studies of the CO2 dispersion process, e.g. Mazzoldi et al. (2007, 2008 and 2011) and Wang et al. (2008), but with different assumptions concerning the pipeline release pressures. To give an idea of realistic release pressures investigations with the CFD tool OpenFOAM were carried out and are presented within this work. To cover such a scenario with an accidental release of carbon dioxide a pipeline section with different diameters and leakage release holes were modelled. This pipeline section is 10m long with the leakage hole in the middle. Additionally a small environment subdomain is simulated around the crack. For computation a multiphase solver was utilised. In a first step incompressible and isothermal fluids with no phase change were assumed.

Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach.

PubMed

Bhattacharyya, P; Roy, K S; Das, M; Ray, S; Balachandar, D; Karthikeyan, S; Nayak, A K; Mohapatra, T

2016-01-15

Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and abundances of C and N decomposing bacteria in lowland rice rhizosphere were found under e-CO2T, which could be explored further for their specific role in nutrient cycling, sustainable agriculture and environment management. Copyright © 2015 Elsevier B.V. All rights reserved.

Carbon dioxide laser versus erbium:YAG laser in treatment of epidermal verrucous nevus: a comparative randomized clinical study.

PubMed

Osman, Mai Abdel Raouf; Kassab, Ahmed Nazmi

2017-08-01

A verrucous epidermal nevus (VEN) is a skin disorder that has been treated using different treatment modalities with varying results. Ablative lasers such as carbon dioxide laser (CO 2 ) and erbium:yttrium-aluminum-garnet (Er:YAG) laser have been considered as the gold standard for the treatment of epidermal nevi. To evaluate and compare the efficacy, postoperative wound healing and side effects of pulsed CO 2 laser and Er:YAG laser for the treatment of verrucous epidermal nevi. Twenty patients with localized VEN were randomly divided into two groups. Group 1 was administered CO 2 laser and group 2 underwent Er:YAG laser treatment. A blinded physician evaluated the photographs and dermoscopic photomicrographs for the efficacy and possible side effects. All patients received one treatment session and were followed up over a 6-month period. Both lasers induced noticeable clinical improvement, but there were no significant differences between two lasers in treatment response, patient satisfaction, duration of erythema and side effects. The average time to re-epithelialization was 13.5 days with CO 2 and 7.9 days with Er:YAG laser (p< .0005). No scarring was observed in Er:YAG laser group and no lesional recurrence was detected in CO 2 laser group since treatment. Apart from re-epithelialization, both lasers showed equivalent outcomes with respect to treatment response, patient satisfaction, side effects and complications.

21 CFR 868.2480 - Cutaneous carbon dioxide (PcCO2) monitor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cutaneous carbon dioxide (PcCO2) monitor. 868.2480... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2480 Cutaneous carbon dioxide (PcCO2) monitor. (a) Identification. A cutaneous carbon dioxide (PcCO2) monitor is a noninvasive heated...

Greenhouse gas emissions from alternative futures of deforestation and agricultural management in the southern Amazon

PubMed Central

Galford, Gillian L.; Melillo, Jerry M.; Kicklighter, David W.; Cronin, Timothy W.; Cerri, Carlos E. P.; Mustard, John F.; Cerri, Carlos C.

2010-01-01

The Brazilian Amazon is one of the most rapidly developing agricultural areas in the world and represents a potentially large future source of greenhouse gases from land clearing and subsequent agricultural management. In an integrated approach, we estimate the greenhouse gas dynamics of natural ecosystems and agricultural ecosystems after clearing in the context of a future climate. We examine scenarios of deforestation and postclearing land use to estimate the future (2006–2050) impacts on carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions from the agricultural frontier state of Mato Grosso, using a process-based biogeochemistry model, the Terrestrial Ecosystems Model (TEM). We estimate a net emission of greenhouse gases from Mato Grosso, ranging from 2.8 to 15.9 Pg CO2-equivalents (CO2-e) from 2006 to 2050. Deforestation is the largest source of greenhouse gas emissions over this period, but land uses following clearing account for a substantial portion (24–49%) of the net greenhouse gas budget. Due to land-cover and land-use change, there is a small foregone carbon sequestration of 0.2–0.4 Pg CO2-e by natural forests and cerrado between 2006 and 2050. Both deforestation and future land-use management play important roles in the net greenhouse gas emissions of this frontier, suggesting that both should be considered in emissions policies. We find that avoided deforestation remains the best strategy for minimizing future greenhouse gas emissions from Mato Grosso. PMID:20651250

End-Tidal Carbon Dioxide Measurement during Pediatric Polysomnography: Signal Quality, Association with Apnea Severity, and Prediction of Neurobehavioral Outcomes

PubMed Central

Paruthi, Shalini; Rosen, Carol L.; Wang, Rui; Weng, Jia; Marcus, Carole L.; Chervin, Ronald D.; Stanley, Jeffrey J.; Katz, Eliot S.; Amin, Raouf; Redline, Susan

2015-01-01

Study Objectives: To identify the role of end-tidal carbon dioxide (EtCO2) monitoring during polysomnography in evaluation of children with obstructive sleep apnea syndrome (OSAS), including the correlation of EtCO2 with other measures of OSAS and prediction of changes in cognition and behavior after adenotonsillectomy. Design: Analysis of screening and endpoint data from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study comparing early adenotonsillectomy (eAT) to watchful waiting/supportive care (WWSC) in children with OSAS. Setting: Multisite clinical referral settings. Participants: Children, ages 5.0 to 9.9 y with suspected sleep apnea. Interventions: eAT or WWSC. Measurements and Results: Quality EtCO2 waveforms were present for ≥ 75% of total sleep time (TST) in 876 of 960 (91.3%) screening polysomnograms. Among the 322 children who were randomized, 55 (17%) met pediatric criteria for hypoventilation. The mean TST with EtCO2 > 50 mmHg was modestly correlated with apnea-hypopnea index (AHI) (r = 0.33; P < 0.0001) and with oxygen saturation ≤ 92% (r = 0.26; P < 0.0001). After adjusting for AHI, obesity, and other factors, EtCO2 > 50 mmHg was higher in African American children than others. The TST with EtCO2 > 50 mmHg decreased significantly more after eAT than WWSC. In adjusted analyses, baseline TST with EtCO2 > 50 mmHg did not predict postoperative changes in cognitive and behavioral measurements. Conclusions: Among children with suspected obstructive sleep apnea syndrome, overnight end-tidal carbon dioxide (EtCO2) levels are weakly to modestly correlated with other polysomnographic indices and therefore provide independent information on hypoventilation. EtCO2 levels improve with adenotonsillectomy but are not as responsive as AHI and do not provide independent prediction of cognitive or behavioral response to surgery. Clinical Trial Registration: Childhood Adenotonsillectomy Study for Children with OSAS (CHAT). ClinicalTrials.gov Identifier #NCT00560859. Citation: Paruthi S, Rosen CL, Wang R, Weng J, Marcus CL, Chervin RD, Stanley JJ, Katz ES, Amin R, Redline S. End-tidal carbon dioxide measurement during pediatric polysomnography: signal quality, association with apnea severity, and prediction of neurobehavioral outcomes. SLEEP 2015;38(11):1719–1726. PMID:26414902

Introduction

Treesearch

David L. Peterson; James M. Vose

2012-01-01

Projected changes in climate (temperature and precipitation means and extreme events), increased atmospheric carbon dioxide (CO2), and increased nitrogen deposition are likely to affect U.S. forests throughout this century. Effects will be both direct (e.g., effects of elevated CO2 on forest growth and water use) and...

ELEVATED CARBON DIOXIDE DIFFERENTIALLY ALTERS THE PHOTOPHYSIOLOGY OF THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE) AND EMILIANIA HUXLEYI (HAPTOPHYTA)(1).

PubMed

McCarthy, Avery; Rogers, Susan P; Duffy, Stephen J; Campbell, Douglas A

2012-06-01

Increasing anthropogenic carbon dioxide is causing changes to ocean chemistry, which will continue in a predictable manner. Dissolution of additional atmospheric carbon dioxide leads to increased concentrations of dissolved carbon dioxide and bicarbonate and decreased pH in ocean water. The concomitant effects on phytoplankton ecophysiology, leading potentially to changes in community structure, are now a focus of concern. Therefore, we grew the coccolithophore Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler and the diatom strains Thalassiosira pseudonana (Hust.) Hasle et Heimdal CCMP 1014 and T. pseudonana CCMP 1335 under low light in turbidostat photobioreactors bubbled with air containing 390 ppmv or 750 ppmv CO2 . Increased pCO2 led to increased growth rates in all three strains. In addition, protein levels of RUBISCO increased in the coastal strains of both species, showing a larger capacity for CO2 assimilation at 750 ppmv CO2 . With increased pCO2 , both T. pseudonana strains displayed an increased susceptibility to PSII photoinactivation and, to compensate, an augmented capacity for PSII repair. Consequently, the cost of maintaining PSII function for the diatoms increased at increased pCO2 . In E. huxleyi, PSII photoinactivation and the counter-acting repair, while both intrinsically larger than in T. pseudonana, did not change between the current and high-pCO2 treatments. The content of the photosynthetic electron transport intermediary cytochrome b6/f complex increased significantly in the diatoms under elevated pCO2 , suggesting changes in electron transport function. © 2012 Phycological Society of America.

Efficacy of supercritical carbon dioxide for nonthermal inactivation of Escherichia coli K12 in apple cider

USDA-ARS?s Scientific Manuscript database

This study evaluated the efficacy of a supercritical carbon dioxide (SCCO2) system with a gas-liquid porous metal contactor for eliminating Escherichia coli K12 in apple cider. Pasteurized, preservative-free apple cider was inoculated with E. coli K12 and processed using the SCCO2 system at CO2 conc...

Biomethane potential of the POME generated in the palm oil industry in Ghana from 2002 to 2009.

PubMed

Arthur, Richard; Glover, Kwasi

2012-05-01

The palm oil industry experienced significant improvement in its production level from 2002 to 2009 from the established companies, medium scale mills (MSM), small scale and other private holdings (SS and OPH) groups. However, the same cannot be said for treatment of the palm oil mill effluent (POME) produced. The quantity of crude palm oil (CPO) produced in Ghana from 2002 to 2009 and IPCC guidelines for National Greenhouse Gas Inventories, specifically on industrial wastewater were used in this study. During this period about 10 million cubic metres of POME was produced translating into biomethane potential of 38.5 million m(3) with equivalent of 388.29 GW h of energy. A linear growth model developed to predict the equivalent carbon dioxide (CO(2)) emissions indicates that if the biomethane is not harnessed then by 2015 the untreated POME could produce 0.58 million tCO(2)-eq and is expected to increase to 0.70 million tCO(2)-eq by 2020. Copyright © 2012 Elsevier Ltd. All rights reserved.

Sensitivity Studies for Space-Based Global Measurements of Atmospheric Carbon Dioxide

NASA Technical Reports Server (NTRS)

Mao, Jian-Ping; Kawa, S. Randolph; Bhartia, P. K. (Technical Monitor)

2001-01-01

Carbon dioxide (CO2) is well known as the primary forcing agent of global warming. Although the climate forcing due to CO2 is well known, the sources and sinks of CO2 are not well understood. Currently the lack of global atmospheric CO2 observations limits our ability to diagnose the global carbon budget (e.g., finding the so-called "missing sink") and thus limits our ability to understand past climate change and predict future climate response. Space-based techniques are being developed to make high-resolution and high-precision global column CO2 measurements. One of the proposed techniques utilizes the passive remote sensing of Earth's reflected solar radiation at the weaker vibration-rotation band of CO2 in the near infrared (approx. 1.57 micron). We use a line-by-line radiative transfer model to explore the potential of this method. Results of sensitivity studies for CO2 concentration variation and geophysical conditions (i.e., atmospheric temperature, surface reflectivity, solar zenith angle, aerosol, and cirrus cloud) will be presented. We will also present sensitivity results for an O2 A-band (approx. 0.76 micron) sensor that will be needed along with CO2 to make surface pressure and cloud height measurements.

Application of copper sulfate pentahydrate as an ammonia removal reagent for the determination of trace impurities in ammonia by gas chromatography.

PubMed

Aomura, Yoko; Kobayashi, Yoshihiko; Miyazawa, Yuzuru; Shimizu, Hideharu

2010-03-12

Rapid analysis of trace permanent gas impurities in high purity ammonia gas for the microelectronics industry is described, using a gas chromatograph equipped with a phtoionization detector. Our system incorporates a reactive precolumn in combination with the analytical column to remove the ammonia matrix peak that otherwise would complicate the measurements due to baseline fluctuations and loss of analytes. The performance of 21 precolumn candidate materials was evaluated. Copper sulfate pentahydrate (CuSO(4).5H(2)O) was shown to selectively react with ammonia at room temperature and atmospheric column pressures, without affecting the hydrogen, oxygen, nitrogen, methane or carbon monoxide peak areas. To prevent loss of trace carbon dioxide, an additional boron trioxide reactant layer was inserted above the copper sulfate pentahydrate bed in the reactive precolumn. Using the combined materials, calibration curves for carbon dioxide proved to be equivalent in both ammonia and helium matrix gases. These curves were equivalent in both matrix gases. The quantitative performance of the system was also evaluated. Peak repeatabilities, based on eight injections, were in the range of 4.1-8.2% relative standard deviation; and detection limits were 6.9 ppb for H(2), 1.8 ppb for O(2), 1.6 ppb for N(2), 6.4 ppb for CH(4), 13 ppb for CO, and 5.4 ppb for CO(2). Copyright (c) 2010 Elsevier B.V. All rights reserved.

Bioelectrochemical conversion of CO2 to chemicals: CO2 as a next generation feedstock for electricity-driven bioproduction in batch and continuous modes.

PubMed

Bajracharya, Suman; Vanbroekhoven, Karolien; Buisman, Cees J N; Strik, David P B T B; Pant, Deepak

2017-09-21

The recent concept of microbial electrosynthesis (MES) has evolved as an electricity-driven production technology for chemicals from low-value carbon dioxide (CO 2 ) using micro-organisms as biocatalysts. MES from CO 2 comprises bioelectrochemical reduction of CO 2 to multi-carbon organic compounds using the reducing equivalents produced at the electrically-polarized cathode. The use of CO 2 as a feedstock for chemicals is gaining much attention, since CO 2 is abundantly available and its use is independent of the food supply chain. MES based on CO 2 reduction produces acetate as a primary product. In order to elucidate the performance of the bioelectrochemical CO 2 reduction process using different operation modes (batch vs. continuous), an investigation was carried out using a MES system with a flow-through biocathode supplied with 20 : 80 (v/v) or 80 : 20 (v/v) CO 2  : N 2 gas. The highest acetate production rate of 149 mg L -1 d -1 was observed with a 3.1 V applied cell-voltage under batch mode. While running in continuous mode, high acetate production was achieved with a maximum rate of 100 mg L -1 d -1 . In the continuous mode, the acetate production was not sustained over long-term operation, likely due to insufficient microbial biocatalyst retention within the biocathode compartment (i.e. suspended micro-organisms were washed out of the system). Restarting batch mode operations resulted in a renewed production of acetate. This showed an apparent domination of suspended biocatalysts over the attached (biofilm forming) biocatalysts. Long term CO 2 reduction at the biocathode resulted in the accumulation of acetate, and more reduced compounds like ethanol and butyrate were also formed. Improvements in the production rate and different biomass retention strategies (e.g. selecting for biofilm forming micro-organisms) should be investigated to enable continuous biochemical production from CO 2 using MES. Certainly, other process optimizations will be required to establish MES as an innovative sustainable technology for manufacturing biochemicals from CO 2 as a next generation feedstock.

Optimizing supercritical carbon dioxide in the inactivation of bacteria in clinical solid waste by using response surface methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hossain, Md. Sohrab; Nik Ab Rahman, Nik Norulaini; Balakrishnan, Venugopal

2015-04-15

Highlights: • Supercritical carbon dioxide sterilization of clinical solid waste. • Inactivation of bacteria in clinical solid waste using supercritical carbon dioxide. • Reduction of the hazardous exposure of clinical solid waste. • Optimization of the supercritical carbon dioxide experimental conditions. - Abstract: Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO{sub 2}) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis,more » and gram-negative Escherichia coli in CSW. The effects of SC-CO{sub 2} sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO{sub 2}-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO{sub 2} exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.« less

Mathematical modeling and experimental breakthrough curves of carbon dioxide adsorption on metal organic framework CPM-5.

PubMed

Sabouni, Rana; Kazemian, Hossein; Rohani, Sohrab

2013-08-20

It is essential to capture carbon dioxide from flue gas because it is considered one of the main causes of global warming. Several materials and different methods have been reported for CO2 capturing including adsorption onto zeolites and porous membranes, as well as absorption in amine solutions. All such methods require high energy input and high cost. A new class of porous materials called Metal Organic Frameworks (MOFs) exhibited excellent performance in extracting carbon dioxide from a gas mixture. In this study, the breakthrough curves for the adsorption of carbon dioxide on CPM-5 (crystalline porous materials) were obtained experimentally and theoretically using a laboratory-scale fixed-bed column at different experimental conditions such as feed flow rate, adsorption temperature, and feed concentration. It was found that the CPM-5 has a dynamic CO2 adsorption capacity of 11.9 wt % (2.7 mmol/g) (corresponding to 8 mL/min, 298 K, and 25% v/v CO2). The tested CPM-5 showed an outstanding adsorption equilibrium capacity (e.g., 2.3 mmol/g (10.2 wt %) at 298 K) compared to other adsorbents, which can be considered as an attractive adsorbent for separation of CO2 from flue gas.

Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making.

PubMed

Rodeheffer, Christopher D; Chabal, Sarah; Clarke, John M; Fothergill, David M

2018-06-01

Submarines routinely operate with higher levels of ambient carbon dioxide (CO2) (i.e., 2000 - 5000 ppm) than what is typically considered normal (i.e., 400 - 600 ppm). Although significant cognitive impairments are rarely reported at these elevated CO2 levels, recent studies using the Strategic Management Simulation (SMS) test have found impairments in decision-making performance during acute CO2 exposure at levels as low as 1000 ppm. This is a potential concern for submarine operations, as personnel regularly make mission-critical decisions that affect the safety and efficiency of the vessel and its crew while exposed to similar levels of CO2. The objective of this study was to determine if submariner decision-making performance is impacted by acute exposure to levels of CO2 routinely present in the submarine atmosphere during sea patrols. Using a subject-blinded balanced design, 36 submarine-qualified sailors were randomly assigned to receive 1 of 3 CO2 exposure conditions (600, 2500, or 15,000 ppm). After a 45-min atmospheric acclimation period, participants completed an 80-min computer-administered SMS test as a measure of decision making. There were no significant differences for any of the nine SMS measures of decision making between the CO2 exposure conditions. In contrast to recent research demonstrating cognitive deficits on the SMS test in students and professional-grade office workers, we were unable to replicate this effect in a submariner population-even with acute CO2 exposures more than an order of magnitude greater than those used in previous studies that demonstrated such effects.Rodeheffer CD, Chabal S, Clarke JM, Fothergill DM. Acute exposure to low-to-moderate carbon dioxide levels and submariner decision making. Aerosp Med Hum Perform. 2018; 89(6):520-525.

Carbon dioxide is tightly bound in the [Co(Pyridine)(CO2)]- anionic complex

NASA Astrophysics Data System (ADS)

Graham, Jacob D.; Buytendyk, Allyson M.; Zhang, Xinxing; Kim, Seong K.; Bowen, Kit H.

2015-11-01

The [Co(Pyridine)(CO2)]- anionic complex was studied through the combination of photoelectron spectroscopy and density functional theory calculations. This complex was envisioned as a primitive model system for studying CO2 binding to negatively charged sites in metal organic frameworks. The vertical detachment energy (VDE) measured via the photoelectron spectrum is 2.7 eV. Our calculations imply a structure for [Co(Pyridine)(CO2)]- in which a central cobalt atom is bound to pyridine and CO2 moieties on either sides. This structure was validated by acceptable agreement between the calculated and measured VDE values. Based on our calculations, we found CO2 to be bound within the anionic complex by 1.4 eV.

Carbon dioxide is tightly bound in the [Co(Pyridine)(CO2)](-) anionic complex.

PubMed

Graham, Jacob D; Buytendyk, Allyson M; Zhang, Xinxing; Kim, Seong K; Bowen, Kit H

2015-11-14

The [Co(Pyridine)(CO2)](-) anionic complex was studied through the combination of photoelectron spectroscopy and density functional theory calculations. This complex was envisioned as a primitive model system for studying CO2 binding to negatively charged sites in metal organic frameworks. The vertical detachment energy (VDE) measured via the photoelectron spectrum is 2.7 eV. Our calculations imply a structure for [Co(Pyridine)(CO2)](-) in which a central cobalt atom is bound to pyridine and CO2 moieties on either sides. This structure was validated by acceptable agreement between the calculated and measured VDE values. Based on our calculations, we found CO2 to be bound within the anionic complex by 1.4 eV.

Investigation of industrial-scale carbon dioxide reduction using pulsed electron beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrov, G. M.; Apruzese, J. P.; Petrova, Tz. B.

Carbon dioxide is the most important greenhouse gas contributing to global warming. To help mitigate increasing CO{sub 2} concentrations, we investigate a method of carbon dioxide reduction using high-power electron beams, which can be used on an industrial scale. A series of experiments are conducted in which the reduction of CO{sub 2} is measured for different gas compositions and power deposition rates. An electron beam deposition model is applied to compute reduction rates of CO{sub 2} and energy cost for breaking a CO{sub 2} molecule in flue gas and pure carbon dioxide at atmospheric pressure. For flue gas consisting ofmore » 82% N{sub 2}, 6% O{sub 2}, and 12% CO{sub 2}, the calculated energy cost is 85 eV per molecule. In order to dissociate 50% of the CO{sub 2} molecules, beam energy density deposition on the order of 20 J/cm{sup 3} is required. Electron beam irradiation of 12.6 liter gas volume containing 90% CO{sub 2} and 10% CH{sub 4} at beam energy density deposition of 4.2 J/cm{sup 3}, accumulated over 43 shots in a 20 min interval, reduced the CO{sub 2} concentration to 78%. Analogous experiments with a gas mixture containing 11.5% CO{sub 2}, 11.5% CH{sub 4}, and balance of Ar, reduced the CO{sub 2} concentration to below 11% with energy deposition 0.71 J/cm{sup 3}, accumulated over 10 shots in a 5 min interval. The experimental data and the theoretical predictions of CO{sub 2} reduction using pulsed electron beams are in agreement within the experimental error. Other techniques to enhance the removal of CO{sub 2} with pulsed electron beams are also explored, yielding new possible avenues of research.« less

Integrated In Situ Sensing and Modeling to Assess Carbon Dioxide Emissions from Tropical Wet Forest Soils: The Role of Leaf Cutter Ant Atta Cepholotes

NASA Astrophysics Data System (ADS)

Harmon, T. C.; Fernandez Bou, A. S.; Dierick, D.; Oberbauer, S. F.; Schwendenmann, L.; Swanson, A. C.; Zelikova, T. J.

2016-12-01

This project focuses on the role of leaf cutter ants (LCA) Atta cepholotes in carbon cycling in neotropical wet forests. LCA are abundant in these forests and workers cut and carry vegetation fragments to their nests, where symbiotic fungi break down the plant material and produce the fungal hyphae on which the ants feed. LCA are the dominant herbivores in tropical forest ecosystems, removing 10-50% of vegetation annually. Their nests can achieve large sizes, extending several meters belowground and covering 50 square meters or more of the forest floor. We monitored soil moisture, temperature, and soil CO2 concentrations continuously in nest and control sites at La Selva Biological Station, Costa Rica. Intermittently, we also assessed soil respiration and LCA nest vent fluxes. Observed soil CO2 concentrations varied markedly with soil moisture conditions, ranging from a few thousand to over 60,000 ppm(v). Accordingly, soil CO2 surface efflux varied temporally by an order of magnitude or more (typical range 0.5 to 5 mmol CO2 m-2 s-1) for the same location as a consequence of soil moisture fluctuations. LCA nest vents equivalent CO2 efflux rates (accounting for vent diameter) can be substantially greater than soil surface values, with observed values ranging from about 1 to 50 mmol m-2 s-1 (it is worth noting that correcting for vent diameters yields equivalent CO2 efflux rates greater than 1000 mmol m-2 s-1). Similar to the soil surface efflux, vent efflux varied temporally by factors of 3 or more, suggesting a potential link between the vent productivity and nest activity, moisture content of surrounding soil, and atmospheric conditions (e.g., air temperature, wind). Using a soil model (Hydrus-1D) to account for unsaturated flow, heat transfer, CO2 production and diffusive transport, we captured moisture and temperature dynamics and the order of magnitude of observed CO2 concentration. Modelled surface fluxes also agreed well with observed soil surface CO2 efflux. These results contribute to our understanding of CO2 production and transport in tropical soils, and the role played by the LCA in the soil carbon cycle.

Development of Fly Ash-Based Sorbent to Capture CO2 from Flue Gas

NASA Astrophysics Data System (ADS)

Majchrzak-Kucęba, I.; Nowak, W.

In the present work the thermogravimetric characterization of the sorption of carbon dioxide on polymer-modifiedmesoporous materials (MCM-41) from fly ashes is described. In order to obtain MCM-41 materials from three different types fly ashes,(including CFB fly ash) hydrothermal processesusing the supernatantsof coal fly ashes and surfactantsas the structure-directing agents,have been carried out. The obtained mesoporous materials were subjected to polyethylenimine (PEI) modification by their impregnation to obtain samples with PEl contents of 30, 50 and 70%, respectively. CO2 sorption/desorption tests on loaded PEl samples were carried out in a flow of a mixture of gasses (CO2-1O%, O2-10%, N2-80%) at different temperatures: 25 and 75°C. The highest CO2 sorption value was obtained for the sample that contained the best-quality MCM-41 and was impregnatedwith PEI in the amount of 50%. This sample at a temperatureof 75°C can take CO2 in an amount equivalent to 111.7 mgCO2/g sample weight. Under the same conditions, but without PEI impregnation, this sample can take CO2 in an amount equivalent to 3.2 mgCO2/g sample weight, thus 35 times less. The research of CO2 adsorption on polymer-modified mesoporous materials from fly ashes carried out within this work has shown that these materials are characterized by high CO2 adsorption capacity under conditions typical of coal combustionboiler flue gas and have the chance of becoming an efficient adsorbent for application to post-combustion CO2 separation. For PEI impregnated samples, a different behaviour of adsorption/desorption profiles has also been observed (both sorption and desorptionprogressesvery rapidly).

Utilization of waste bittern from saltern as a source for magnesium and an absorbent for carbon dioxide capture.

PubMed

Na, Choon-Ki; Park, Hyunju; Jho, Eun Hea

2017-10-01

During solar salt production, large quantities of bittern, a liquid by-product containing high inorganic substance concentrations, are produced. The purpose of this research was to examine the utilization of waste bittern generated from salterns as a source for Mg production and as an absorbent for carbon dioxide (CO 2 ) capture. The study was conducted in a sequential two-step process. At NaOH/Mg molar ratios of 2.70-2.75 and pH 9.5-10.0, > 99% Mg precipitation from the bittern was achieved. After washing with water, 100-120 g/L of precipitate containing 94% Mg(OH) 2 was recovered from the bittern. At the optimum NH 4 OH concentration of 5%, 120 g of sodium bicarbonate precipitate per liter of bittern were recovered, which was equivalent to 63 g CO 2 captured per liter of bittern. These results can be used to support the use of bittern as a resource and reduce economic losses during solar salt production.

Low-cost photonic sensors for carbon dioxide exchange rate measurement

NASA Astrophysics Data System (ADS)

Bieda, Marcin S.; Sobotka, Piotr; Lesiak, Piotr; Woliński, Tomasz R.

2017-10-01

Carbon dioxide (CO2) measurement has an important role in atmosphere monitoring. Usually, two types of measurements are carried out. The first one is based on gas concentration measurement while the second involves gas exchange rate measurement between earth surface and atmosphere [1]. There are several methods which allow gas concentration measurement. However, most of them require expensive instrumentation or large devices (i.e. gas chambers). In order to precisely measure either CO2 concentration or CO2 exchange rate, preferably a sensors network should be used. These sensors must have small dimensions, low power consumption, and they should be cost-effective. Therefore, this creates a great demand for a robust low-power and low-cost CO2 sensor [2,3]. As a solution, we propose a photonic sensor that can measure CO2 concentration and also can be used to measure gas exchange by using the Eddy covariance method [1].

Quantifying direct carbon dioxide emissions from wastewater treatment units by nondispersive infrared sensor (NDIR) - A pilot study.

PubMed

Kosse, Pascal; Kleeberg, Tasja; Lübken, Manfred; Matschullat, Jörg; Wichern, Marc

2018-08-15

Treatment of nutrient-rich wastewater potentially results in direct release of greenhouse gases (GHGs) such as CO 2 , N 2 O or CH 4 - and thus affects Waste Water Treatment Plant's carbon footprint. Accurate CO 2 quantification is challenging due to various chemical, physical and operational conditions. A floating chamber equipped with a nondispersive infrared, single beam, dual wavelength sensor has been evaluated for a pilot approach to quantify fugitive CO 2 emissions above different wastewater treatment units. Total average CO 2 flux was 1182gCO 2 ·m -2 ·d -1 with minimum and maximum fluxes of 829gCO 2 ·m -2 ·d -1 and 1493gCO 2 ·m -2 ·d -1 , respectively. Total observed CO 2 emissions were in 7 to 17kgCO 2 ·PE -1 ·a -1 (average 12kgCO 2 ·PE -1 ·a -1 ). The nitrification tank accounted for about 94.3% of the emissions, followed by secondary clarification (ca. 4.3%) and denitrification (ca. 1.4%), based on those average annual CO 2 emissions per population equivalent (PE). Copyright © 2018 Elsevier B.V. All rights reserved.

Absorption of Carbon Dioxide in Aqueous Solutions of N-methyldiethanolamine Mixtures

NASA Astrophysics Data System (ADS)

Ma’mun, S.; Svendsen, H. F.

2018-05-01

Carbon dioxide (CO2) is one of the greenhouse gases (GHG) that has contributed to the global warming problem. Carbon dioxide is produced in large quantity from coal-fired power plants, iron and steel production, cement production, chemical and petrochemical industries, natural gas purification, and transportation. Some efforts to reduce the CO2 emissions to the atmosphere are then required. Amine-based absorption may be an option for post-combustion capture. The objective of this study is to measure the effect of promoter addition as well as MDEA concentration for the CO2 absorption into the aqueous solutions of MDEA to improve its performances, i.e. increasing the absorption rate and the absorption capacity. Absorption of CO2 in aqueous solutions of MDEA mixtures were measured at 40 °C in a bubble tank reactor. The systems tested were the mixtures of 30 wt% MDEA with 5 and 10 wt% BEA and the mixtures of 40 and 50 wt% MDEA with 6 wt% AEEA. It was found that for MDEA-BEA-H2O mixtures, the higher the promoter concentraation the higher the CO2 absorption rate, while for the MDEA-AEEA-H2O mixtures, the higher the MDEA concentration the lower the CO2 absorption rate.

Using carbon dioxide in fisheries and aquatic invasive species management

USGS Publications Warehouse

Treanor, Hilary B.; Ray, Andrew M.; Layhee, Megan J.; Watten, Barnaby J.; Gross, Jason A.; Gresswell, Robert E.; Webb, Molly A. H.

2017-01-01

To restore native fish populations, fisheries programs often depend on active removal of aquatic invasive species. Chemical removal can be an effective method of eliminating aquatic invasive species, but chemicals can induce mortality in nontarget organisms and persist in the environment. Carbon dioxide (CO2) is an emerging alternative to traditional chemical control agents because it has been demonstrated to be toxic to fish, but is naturally occurring and readily neutralized. In addition, CO2 is a commercially available gas, is highly soluble, and has high absorption efficiency. When these characteristics are paired with advances in modern, large-scale gas delivery technologies, opportunities to use CO2 in natural or artificial (e.g., canals) waters to manage fish become increasingly feasible. Our objective is to describe the history of CO2 use in fisheries and outline potential future applications of CO2 to suppress and manipulate aquatic species in field and aquaculture settings.

Space-based active optical remote sensing of carbon dioxide column using high-energy two-micron pulsed ipda lidar

NASA Astrophysics Data System (ADS)

Singh, Upendra N.; Refaat, Tamer F.; Ismail, Syed; Petros, Mulugeta; Davis, Kenneth J.; Kawa, Stephan R.; Menzies, Robert T.

2018-04-01

Modeling of a space-based high-energy 2-μm triple-pulse Integrated Path Differential Absorption (IPDA) lidar was conducted to demonstrate carbon dioxide (CO2) measurement capability and to evaluate random and systematic errors. A high pulse energy laser and an advanced MCT e-APD detector were incorporated in this model. Projected performance shows 0.5 ppm precision and 0.3 ppm bias in low-tropospheric column CO2 mixing ratio measurements from space for 10 second signal averaging over Railroad Valley (RRV) reference surface.

Comparison of a fractional microplasma radio frequency technology and carbon dioxide fractional laser for the treatment of atrophic acne scars: a randomized split-face clinical study.

PubMed

Zhang, Zhen; Fei, Ye; Chen, Xiangdong; Lu, Wenli; Chen, Jinan

2013-04-01

No studies have compared fractional microplasma radio frequency (RF) technology with the carbon dioxide fractional laser system (CO2 FS) in the treatment of atrophic acne scars in the same patient. To compare the efficacy and safety of fractional microplasma RF with CO2 FS in the treatment of atrophic acne scars. Thirty-three Asian patients received three sessions of a randomized split-face treatment of fractional microplasma RF or CO2 FS. Both modalities had a roughly equivalent effect. Échelle d'Évaluation Clinique Des Cicatrices d'Acné scores were significantly lower after fractional microplasma RF (from 51.1 ± 14.2 to 22.3 ± 8.6, 56.4% improvement) and CO2 FS (from 48.8 ± 15.1 to 19.9 ± 7.9, 59.2% improvement) treatments. There was no statistically significant difference between the two therapies. Twelve subjects (36.4%) experienced postinflammatory hyperpigmentation (PIH) after 30 of 99 treatment sessions (30.3%) on the CO2 FS side and no PIH was observed on the fractional microplasma RF sides. Both modalities have good effects on treating atrophic scars. PIH was not seen with the fractional microplasma RF, which might make it a better choice for patients with darker skin. © 2013 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Potential contributions of food consumption patterns to climate change.

PubMed

Carlsson-Kanyama, Annika; González, Alejandro D

2009-05-01

Anthropogenic warming is caused mainly by emissions of greenhouse gases (GHGs), such as carbon dioxide, methane, and nitrous oxide, with agriculture as a main contributor for the latter 2 gases. Other parts of the food system contribute carbon dioxide emissions that emanate from the use of fossil fuels in transportation, processing, retailing, storage, and preparation. Food items differ substantially when GHG emissions are calculated from farm to table. A recent study of approximately 20 items sold in Sweden showed a span of 0.4 to 30 kg CO(2) equivalents/kg edible product. For protein-rich food, such as legumes, meat, fish, cheese, and eggs, the difference is a factor of 30 with the lowest emissions per kilogram for legumes, poultry, and eggs and the highest for beef, cheese, and pork. Large emissions for ruminants are explained mainly by methane emissions from enteric fermentation. For vegetables and fruits, emissions usually are

Site Location Details, Air Pollution Monitoring Equipment Used, Aircraft Flight Path Information, and Deployment Configuration for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) Field Campaign in Colorado: Summer 2014

EPA Science Inventory

For EPA, this Summer 2014, Denver CO, DISCOVER-AQ field research activity focused on assessing Federal Reference Methods (FRMs) and Federal Equivalent Methods (FEMs) for ozone (O3) and Nitrogen Dioxide (NO2), while comparing their operational performance to each other and to smal...

Miniaturized Amperometric Solid Electrolyte Carbon Dioxide Sensors

NASA Technical Reports Server (NTRS)

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

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.

40 CFR 98.124 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... in paragraph (b)(8) of this section only if the total annual CO2-equivalent fluorinated GHG... terms of total CO2 equivalents. For fluorinated GHGs whose GWPs are not listed in Table A-1 to subpart A... control purposes and may include but are not limited to yields, pressures, temperatures, etc. (e.g., of...

40 CFR 98.124 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... in paragraph (b)(8) of this section only if the total annual CO2-equivalent fluorinated GHG... terms of total CO2 equivalents. For fluorinated GHGs whose GWPs are not listed in Table A-1 to subpart A... control purposes and may include but are not limited to yields, pressures, temperatures, etc. (e.g., of...

Arterial-to-end-tidal carbon dioxide tension difference in children with congenital heart disease.

PubMed

Choudhury, Minati; Kiran, Usha; Choudhary, Shiv Kumar; Airan, Balram

2006-04-01

This study estimated the arterial-to-end-tidal carbon dioxide tension difference (deltaPaCO2-PE'CO2) in children with congenital heart disease; evaluated whether hyperventilation can reduce this difference; and analyzed the relationship between the difference and the oxygen saturation (SaO2) and hemoglobin level. Prospective clinical study. Tertiary health care center. One hundred patients scheduled for correction of their underlying cardiac defect with either right-to-left or left-to-right intracardiac shunts were divided into 4 groups (n = 25 each): (1) N1, cyanotic with severe pulmonary artery hypertension; (2) N2, cyanotic with normal or decreased pulmonary artery pressure (PAP); (3) N3, acyanotic with normal or mild increases in PAP and severe increases in pulmonary blood flow (PBF); and (4) N4, acyanotic with normal PAP and normal or mild increase in PBF. All the patients received the same anesthetic regimen. The initial settings for tidal volume, respiratory rate, and inspiratory-to-expiratory (I:E) ratio were 10 mL/kg, 15 to 30 breath/min, and inspired time 40% of the total respiratory period with a 10% end-inspiratory pause. After the measurement of oxygen saturation, PO2, Hb, and deltaPaCO2-PE'CO2, all the children were hyperventilated (tidal volume: 14-15 mL/kg, respiratory rate: 5-6 breaths/min more than the initial rate, I:E ratio: same) to observe its effects on the deltaPaCO2-PE'CO2. The deltaPaCO2-PE'CO2, when predicted from the oxygen saturation, hemoglobin concentration, and PaO2, was found to be greater than the observed value in the first 3 groups (p < 0.001); whereas in group N4 these 2 values were comparable. It was also found that the gradient was higher when there was a decrease in SaO2 and an increase in the hemoglobin level. After hyperventilation, in groups N1 and N3, deltaPaCO2-PE'CO2 was decreased when compared with their baseline values; this reduction was not as much as predicted (p = 0.363 and 0.236, respectively). However, in groups N2 and N4 posthyperventilation, the deltaPaCO2-PE'27 CO2 was decreased significantly below their baseline measurements. These decreases were as much predicted. The deltaPaCO2-end-tidal carbon dioxide (PE'CO2) can be increased both in cyanotic and acyanotic children. Increased PAP is as important as increased PBF or right-to-left shunting in producing disorders in carbon dioxide homeostasis. Hyperventilation is of little use in reducing deltaPaCO2-PE'CO2 in children with high PAPs and pulmonary hyperperfusion.

Hybrid bioinorganic approach to solar-to-chemical conversion.

PubMed

Nichols, Eva M; Gallagher, Joseph J; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C Y; Chang, Christopher J

2015-09-15

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥ 7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion.

Sustainable biochar to mitigate global climate change

PubMed Central

Woolf, Dominic; Amonette, James E.; Street-Perrott, F. Alayne; Lehmann, Johannes; Joseph, Stephen

2010-01-01

Production of biochar (the carbon (C)-rich solid formed by pyrolysis of biomass) and its storage in soils have been suggested as a means of abating climate change by sequestering carbon, while simultaneously providing energy and increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity and sustainability of biochar at the global level. In this paper we estimate the maximum sustainable technical potential of biochar to mitigate climate change. Annual net emissions of carbon dioxide (CO2), methane and nitrous oxide could be reduced by a maximum of 1.8 Pg CO2-C equivalent (CO2-Ce) per year (12% of current anthropogenic CO2-Ce emissions; 1 Pg=1 Gt), and total net emissions over the course of a century by 130 Pg CO2-Ce, without endangering food security, habitat or soil conservation. Biochar has a larger climate-change mitigation potential than combustion of the same sustainably procured biomass for bioenergy, except when fertile soils are amended while coal is the fuel being offset. PMID:20975722

Hybrid bioinorganic approach to solar-to-chemical conversion

PubMed Central

Nichols, Eva M.; Gallagher, Joseph J.; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C. Y.; Chang, Christopher J.

2015-01-01

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion. PMID:26305947

Retinoids, 585-nm laser, and carbon dioxide laser: a numeric comparison of neocollagen formation in photoaged hairless mouse skin.

PubMed

Lee, C J; Park, J H; Ciesielski, T E; Thomson, J G; Persing, J A

2008-11-01

A variety of new methods for treating photoaging have been recently introduced. There has been increasing interest in comparing the relative efficacy of multiple methods for photoaging. However, the efficacy of a single method is difficult to assess from the data reported in the literature. Photoaged hairless mice were randomly divided into seven treatment groups: control, retinoids (tretinoin and adapalene), lasers (585 nm and CO(2)), and combination groups (585 nm + adapalene and CO(2 )+ adapalene). Biopsies were taken from the treated regions, and the results were analyzed based on the repair zone. The repair zones of the various methods for photoaging were compared. Retinoids produced a wider repair zone than the control condition. The 585-nm and CO(2) laser resurfacing produced a result equivalent to that of the control condition. A combination of these lasers with adapalene produced a wider repair zone than the lasers alone, but the combination produced a result equivalent to that of adapalene alone. Retinoids are potent stimuli for neocollagen formation. The 585-nm or CO(2) laser alone did not induce more neocollagen than the control condition. In addition, no synergistic effect was observed with the combination treatments. The repair zone of the combination treatment is mainly attributable to adapalene.

Intelligent Bioreactor Management Information System (IBM-IS) for Mitigation of Greenhouse Gas Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul Imhoff; Ramin Yazdani; Don Augenstein

Methane is an important contributor to global warming with a total climate forcing estimated to be close to 20% that of carbon dioxide (CO2) over the past two decades. The largest anthropogenic source of methane in the US is 'conventional' landfills, which account for over 30% of anthropogenic emissions. While controlling greenhouse gas emissions must necessarily focus on large CO2 sources, attention to reducing CH4 emissions from landfills can result in significant reductions in greenhouse gas emissions at low cost. For example, the use of 'controlled' or bioreactor landfilling has been estimated to reduce annual US greenhouse emissions by aboutmore » 15-30 million tons of CO2 carbon (equivalent) at costs between $3-13/ton carbon. In this project we developed or advanced new management approaches, landfill designs, and landfill operating procedures for bioreactor landfills. These advances are needed to address lingering concerns about bioreactor landfills (e.g., efficient collection of increased CH4 generation) in the waste management industry, concerns that hamper bioreactor implementation and the consequent reductions in CH4 emissions. Collectively, the advances described in this report should result in better control of bioreactor landfills and reductions in CH4 emissions. Several advances are important components of an Intelligent Bioreactor Management Information System (IBM-IS).« less

Carbon dioxide sensor

DOEpatents

Dutta, Prabir K [Worthington, OH; Lee, Inhee [Columbus, OH; Akbar, Sheikh A [Hilliard, OH

2011-11-15

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).

Evaluating the energy performance of a hybrid membrane-solvent process for flue gas carbon dioxide capture

DOE PAGES

Kusuma, Victor A.; Li, Zhiwei; Hopkinson, David; ...

2016-10-13

In this study, a particularly energy intensive step in the conventional amine absorption process to remove carbon dioxide is solvent regeneration using a steam stripping column. An attractive alternative to reduce the energy requirement is gas pressurized stripping, in which a high pressure noncondensable gas is used to strip CO 2 off the rich solvent stream. The gas pressurized stripping column product, having CO 2 at high concentration and high partial pressure, can then be regenerated readily using membrane separation. In this study, we performed an energetic analysis in the form of total equivalent work and found that, for capturingmore » CO 2 from flue gas, this hybrid stripping process consumes 49% less energy compared to the base case conventional MEA absorption/steam stripping process. We also found the amount of membrane required in this process is much less than required for direct CO 2 capture from the flue gas: approximately 100-fold less than a previously published two-stage cross-flow scheme, mostly due to the more favorable pressure ratio and CO 2 concentration. There does exist a trade-off between energy consumption and required membrane area that is most strongly affected by the gas pressurized stripper operating pressure. While initial analysis looks promising from both an energy requirement and membrane unit capital cost, the viability of this hybrid process depends on the availability of advanced, next generation gas separation membranes to perform the stripping gas regeneration.« less

Evaluating the energy performance of a hybrid membrane-solvent process for flue gas carbon dioxide capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusuma, Victor A.; Li, Zhiwei; Hopkinson, David

In this study, a particularly energy intensive step in the conventional amine absorption process to remove carbon dioxide is solvent regeneration using a steam stripping column. An attractive alternative to reduce the energy requirement is gas pressurized stripping, in which a high pressure noncondensable gas is used to strip CO 2 off the rich solvent stream. The gas pressurized stripping column product, having CO 2 at high concentration and high partial pressure, can then be regenerated readily using membrane separation. In this study, we performed an energetic analysis in the form of total equivalent work and found that, for capturingmore » CO 2 from flue gas, this hybrid stripping process consumes 49% less energy compared to the base case conventional MEA absorption/steam stripping process. We also found the amount of membrane required in this process is much less than required for direct CO 2 capture from the flue gas: approximately 100-fold less than a previously published two-stage cross-flow scheme, mostly due to the more favorable pressure ratio and CO 2 concentration. There does exist a trade-off between energy consumption and required membrane area that is most strongly affected by the gas pressurized stripper operating pressure. While initial analysis looks promising from both an energy requirement and membrane unit capital cost, the viability of this hybrid process depends on the availability of advanced, next generation gas separation membranes to perform the stripping gas regeneration.« less

Hybrid organic-inorganic connectivity of NdIII(pyrazine-N,N'-dioxide)[CoIII(CN)6]3- coordination chains for creating near-infrared emissive Nd(iii) showing field-induced slow magnetic relaxation.

PubMed

Chorazy, Szymon; Charytanowicz, Tomasz; Wang, Junhao; Ohkoshi, Shin-Ichi; Sieklucka, Barbara

2018-05-29

A near-infrared emissive and magnetically anisotropic Nd(iii) complex is formed within a hybrid organic-inorganic {[NdIII(pzdo)(H2O)4][CoIII(CN)6]}·0.5(pzdo)·4H2O (1) (pzdo = pyrazine-N,N'-dioxide) ladder chain built of coexisting Nd-pzdo-Nd and Nd-NC-Co molecular bridges. 1 reveals two NdIII-centered properties, a field-induced slow magnetic relaxation of a single-ion origin with a thermal energy barrier of ΔE/kB = 51(2) K at Hdc = 1 kOe, and a near-infrared fluorescence sensitized by organic and inorganic linkers.

A carbon isotope challenge to the snowball Earth.

PubMed

Sansjofre, P; Ader, M; Trindade, R I F; Elie, M; Lyons, J; Cartigny, P; Nogueira, A C R

2011-10-05

The snowball Earth hypothesis postulates that the planet was entirely covered by ice for millions of years in the Neoproterozoic era, in a self-enhanced glaciation caused by the high albedo of the ice-covered planet. In a hard-snowball picture, the subsequent rapid unfreezing resulted from an ultra-greenhouse event attributed to the buildup of volcanic carbon dioxide (CO(2)) during glaciation. High partial pressures of atmospheric CO(2) (pCO2; from 20,000 to 90,000 p.p.m.v.) in the aftermath of the Marinoan glaciation (∼635 Myr ago) have been inferred from both boron and triple oxygen isotopes. These pCO2 values are 50 to 225 times higher than present-day levels. Here, we re-evaluate these estimates using paired carbon isotopic data for carbonate layers that cap Neoproterozoic glacial deposits and are considered to record post-glacial sea level rise. The new data reported here for Brazilian cap carbonates, together with previous ones for time-equivalent units, provide estimates lower than 3,200 p.p.m.v.--and possibly as low as the current value of ∼400 p.p.m.v. Our new constraint, and our re-interpretation of the boron and triple oxygen isotope data, provide a completely different picture of the late Neoproterozoic environment, with low atmospheric concentrations of carbon dioxide and oxygen that are inconsistent with a hard-snowball Earth.

Greenhouse gas reduction by recovery and utilization of landfill methane and CO{sub 2} technical and market feasibility study, Boului Landfill, Bucharest, Romania. Final report, September 30, 1997--September 19, 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, W.J.; Brown, W.R.; Siwajek, L.

1998-09-01

The project is a landfill gas to energy project rated at about 4 megawatts (electric) at startup, increasing to 8 megawatts over time. The project site is Boului Landfill, near Bucharest, Romania. The project improves regional air quality, reduces emission of greenhouse gases, controls and utilizes landfill methane, and supplies electric power to the local grid. The technical and economic feasibility of pre-treating Boului landfill gas with Acrion`s new landfill gas cleanup technology prior to combustion for power production us attractive. Acrion`s gas treatment provides several benefits to the currently structured electric generation project: (1) increase energy density of landfillmore » gas from about 500 Btu/ft{sup 3} to about 750 Btu/ft{sup 3}; (2) remove contaminants from landfill gas to prolong engine life and reduce maintenance;; (3) recover carbon dioxide from landfill gas for Romanian markets; and (4) reduce emission of greenhouse gases methane and carbon dioxide. Greenhouse gas emissions reduction attributable to successful implementation of the landfill gas to electric project, with commercial liquid CO{sub 2} recovery, is estimated to be 53 million metric tons of CO{sub 2} equivalent of its 15 year life.« less

The coupling of glycolysis and the Rubisco-based pathway through the non-oxidative pentose phosphate pathway to achieve low carbon dioxide emission fermentation.

PubMed

Li, Ya-Han; Ou-Yang, Fan-Yu; Yang, Cheng-Han; Li, Si-Yu

2015-01-01

In this study, Rubisco-based engineered Escherichia coli, containing two heterologous enzymes of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoribulokinase (PrkA), has been shown to be capable of the in situ recycling of carbon dioxide (CO2) during glycolysis. Two alternative approaches have been proposed to further enhance the carbon flow from glycolysis to a Rubisco-based pathway through the non-oxidative pentose phosphate pathway (NOPPP). The first is achieved by elevating the expression of transketolase I (TktA) and the second by blocking the native oxidation-decarboxylation reaction of E. coli by deleting the zwf gene from the chromosome (designated as JB/pTA and MZB, respectively). Decreases in the CO2 yield and the CO2 evolution per unit mole of ethanol production by at least 81% and 40% are observed. It is demonstrated in this study that the production of one mole of ethanol using E. coli strain MZB, the upper limit of CO2 emission is 0.052mol. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reproducibility of the exponential rise technique of CO(2) rebreathing for measuring P(v)CO(2) and C(v)CO(2 )to non-invasively estimate cardiac output during incremental, maximal treadmill exercise.

PubMed

Cade, W Todd; Nabar, Sharmila R; Keyser, Randall E

2004-05-01

The purpose of this study was to determine the reproducibility of the indirect Fick method for the measurement of mixed venous carbon dioxide partial pressure (P(v)CO(2)) and venous carbon dioxide content (C(v)CO(2)) for estimation of cardiac output (Q(c)), using the exponential rise method of carbon dioxide rebreathing, during non-steady-state treadmill exercise. Ten healthy participants (eight female and two male) performed three incremental, maximal exercise treadmill tests to exhaustion within 1 week. Non-invasive Q(c) measurements were evaluated at rest, during each 3-min stage, and at peak exercise, across three identical treadmill tests, using the exponential rise technique for measuring mixed venous PCO(2) and CCO(2) and estimating venous-arterio carbon dioxide content difference (C(v-a)CO(2)). Measurements were divided into measured or estimated variables [heart rate (HR), oxygen consumption (VO(2)), volume of expired carbon dioxide (VCO(2)), end-tidal carbon dioxide (P(ET)CO(2)), arterial carbon dioxide partial pressure (P(a)CO(2)), venous carbon dioxide partial pressure ( P(v)CO(2)), and C(v-a)CO(2)] and cardiorespiratory variables derived from the measured variables [Q(c), stroke volume (V(s)), and arteriovenous oxygen difference ( C(a-v)O(2))]. In general, the derived cardiorespiratory variables demonstrated acceptable (R=0.61) to high (R>0.80) reproducibility, especially at higher intensities and peak exercise. Measured variables, excluding P(a)CO(2) and C(v-a)CO(2), also demonstrated acceptable (R=0.6 to 0.79) to high reliability. The current study demonstrated acceptable to high reproducibility of the exponential rise indirect Fick method in measurement of mixed venous PCO(2) and CCO(2) for estimation of Q(c) during incremental treadmill exercise testing, especially at high-intensity and peak exercise.

Varying response of the concentration and content of soybean seed mineral elements, carbohydrates, organic acids, amino acids, protein, and oil to phosphorus starvation and CO2 enrichment

USDA-ARS?s Scientific Manuscript database

A detailed investigation of the concentration (g-1 seed weight) and content (g plant-1) of seed mineral elements and metabolic profile under phosphorus (P) starvation at ambient (aCO2) and elevated carbon dioxide (eCO2) in soybean is limited. Soybean plants were grown in a controlled environment at ...

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

NASA Technical Reports Server (NTRS)

Swickrath, Michael J.; Anderson, Molly

2011-01-01

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.

Three dimensional global modeling of atmospheric CO2

NASA Technical Reports Server (NTRS)

Fung, I.; Hansen, J.; Rind, D.

1983-01-01

A model was developed to study the prospects of extracting information on carbon dioxide sources and sinks from observed CO2 variations. The approach uses a three dimensional global transport model, based on winds from a 3-D general circulation model (GCM), to advect CO2 noninteractively, i.e., as a tracer, with specified sources and sinks of CO2 at the surface. The 3-D model employed is identified and biosphere, ocean and fossil fuel sources and sinks are discussed. Some preliminary model results are presented.

Photodissociation Efficiency Spectroscopy Study of the Rydberg Excited Ion-Pair States of Carbon Dioxide

NASA Astrophysics Data System (ADS)

Feng, Qiang; Xu, Yun-Feng; Sun, Jin-Da; Tian, Shan-Xi; Shan, Xiao-Bin; Liu, Fu-Yi; Sheng, Liu-Si

2009-10-01

Photodissociation efficiency spectrum of anionic oxygen atom produced via ion-pair dissociations of carbon dioxide is recorded by means of the synchrotron radiation excitation (XUV photon energy 17.40-20.00 eV). The present spectrum is assigned as the Rydberg-like excited ion-pair states, i.e., Tanaka-Ogawa and Henning series, tilde C2Σg+ (CO+2) vibrational ground-state and excitation series. Three Rydberg series, npσu, npπu, and nfu, converging to tilde C2Σg+ (0, 0, 0), show the higher cross sections.

Comparison of Carbon Dioxide Airborne Measurement over Land and Ocean using 2-μm Double-Pulse Integrated Path Differential Absorption Lidar

NASA Astrophysics Data System (ADS)

Refaat, T. F.; Singh, U. N.; Petros, M.; Yu, J.; Remus, R.; Ismail, S.

2017-12-01

An airborne Integrated Path Differential Absorption (IPDA) lidar has been developed and validated at NASA Langley Research Center for atmospheric carbon dioxide column measurements. The instrument consists of a tunable, high-energy 2-μm double pulse laser transmitter and 0.4 m telescope receiver coupled to an InGaAs pin detection system. The instrument was validated for carbon dioxide (CO2) measurements from ground and airborne platforms, using a movable lidar trailer and the NASA B-200 aircraft. Airborne validation was conducted over the ocean by comparing the IPDA CO2 optical depth measurement to optical depth model derived using NOAA airborne CO2 air-sampling. Another airborne validation was conducted over land vegetation by comparing the IPDA measurement to a model derived using on-board in-situ measurements using an absolute, non-dispersive infrared gas analyzer (LiCor 840A). IPDA range measurements were also compared to rangefinder and Global Positioning System (GPS) records during ground and airborne validation, respectively. Range measurements from the ground indicated a 0.93 m IPDA range measurement uncertainty, which is limited by the transmitted laser pulse and detection system properties. This uncertainty increased to 2.80 and 7.40 m over ocean and land, due to fluctuations in ocean surface and ground elevations, respectively. IPDA CO2 differential optical depth measurements agree with both models. Consistent CO2 optical depth biases were well correlated with the digitizer full scale input range settings. CO2 optical depth measurements over ocean from 3.1 and 6.1 km altitudes indicated 0.95% and 0.83% uncertainty, respectively, using 10 second (100 shots) averaging. Using the same averaging 0.40% uncertainty was observed over land, from 3.4 km altitude, due to higher surface reflectivity, which increases the return signal power and enhances the signal-to-noise ratio. However, less uncertainty is observed at higher altitudes due to reduced signal shot noise, indicating that detection system noise-equivalent-power dominates the error. These results show that the IPDA technique is well suited for space-based platforms, which includes larger column content integration that enhances the measurement sensitivity.

Formation of pseudo-microgravity environment for dusty plasmas in supercritical carbon dioxide

NASA Astrophysics Data System (ADS)

Sakakibara, Noritaka; Matsubayashi, Yasuhito; Ito, Tsuyohito; Terashima, Kazuo

2018-01-01

We realized a pseudo-microgravity environment for dusty plasmas in a ground-based experiment, using the field-emitting regime of a surface dielectric barrier discharge in high-pressure carbon dioxide (CO2) including supercritical conditions. Using the high and adjustable density of high-pressure CO2, the balance between gravitational force and buoyancy was controlled. When changing the density of CO2 in the range of 0.234 g/cm3 to 0.668 g/cm3, i.e., smaller and larger than that of the particles (0.5 g/cm3), a particle arrangement in the direction of the gravitational force was formed only when the density of CO2 was in the range of ±0.17 g/cm3 with respect to that of the particles. This experimentally demonstrates that the pseudo-microgravity that emerges due to the buoyancy from the high-pressure CO2 contributes to the particle arrangement in the gravitational direction, and hence, it compensates the gravity-induced anisotropy.

Pulmonary Gas Exchange Abnormalities in Mild Chronic Obstructive Pulmonary Disease. Implications for Dyspnea and Exercise Intolerance.

PubMed

Elbehairy, Amany F; Ciavaglia, Casey E; Webb, Katherine A; Guenette, Jordan A; Jensen, Dennis; Mourad, Sahar M; Neder, J Alberto; O'Donnell, Denis E

2015-06-15

Several studies in mild chronic obstructive pulmonary disease (COPD) have shown a higher than normal ventilatory equivalent for carbon dioxide ([Formula: see text]e/[Formula: see text]co2) during exercise. Our objective was to examine pulmonary gas exchange abnormalities and the mechanisms of high [Formula: see text]e/[Formula: see text]co2 in mild COPD and its impact on dyspnea and exercise intolerance. Twenty-two subjects (11 patients with GOLD [Global Initiative for Chronic Obstructive Lung Disease] grade 1B COPD, 11 age-matched healthy control subjects) undertook physiological testing and a symptom-limited incremental cycle exercise test with arterial blood gas collection. Patients (post-bronchodilator FEV1: 94 ± 10% predicted; mean ± SD) had evidence of peripheral airway dysfunction and reduced peak oxygen uptake compared with control subjects (80 ± 18 vs. 113 ± 24% predicted; P<0.05). Arterial blood gases were within the normal range and effective alveolar ventilation was not significantly different from control subjects throughout exercise. The alveolar-arterial O2 tension gradient was elevated at rest and throughout exercise in COPD (P<0.05). [Formula: see text]e/[Formula: see text]co2, dead space to tidal volume ratio (Vd/Vt), and arterial to end-tidal CO2 difference were all higher (P<0.05) in patients with COPD than in control subjects during exercise. In patients with COPD versus control subjects, there was significant dynamic hyperinflation and greater tidal volume constraints (P<0.05). Standardized dyspnea intensity ratings were also higher (P<0.05) in patients with COPD versus control subjects in association with higher ventilatory requirements. Within all subjects, Vd/Vt correlated with the [Formula: see text]e/[Formula: see text]co2 ratio during submaximal exercise (r=0.780, P<0.001). High Vd/Vt was the most consistent gas exchange abnormality in smokers with only mild spirometric abnormalities. Compensatory increases in minute ventilation during exercise maintained alveolar ventilation and arterial blood gas homeostasis but at the expense of earlier dynamic mechanical constraints, greater dyspnea, and exercise intolerance in mild COPD.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan Qi; Saunders, Samuel E.; Bartelt-Hunt, Shannon L., E-mail: sbartelt2@unl.edu

Highlights: Black-Right-Pointing-Pointer This study evaluates methane and carbon dioxide production after land burial of cattle carcasses. Black-Right-Pointing-Pointer Disposal of animal mortalities is often overlooked in evaluating the environmental impacts of animal production. Black-Right-Pointing-Pointer we quantify annual emissions from cattle carcass disposal in the United States as 1.6 Tg CO{sub 2} equivalents. - Abstract: Approximately 2.2 million cattle carcasses require disposal annually in the United States. Land burial is a convenient disposal method that has been widely used in animal production for disposal of both daily mortalities as well as during catastrophic mortality events. To date, greenhouse gas production after mortalitymore » burial has not been quantified, and this study represents the first attempt to quantify greenhouse gas emissions from land burial of animal carcasses. In this study, anaerobic decomposition of both homogenized and unhomogenized cattle carcass material was investigated using bench-scale reactors. Maximum yields of methane and carbon dioxide were 0.33 and 0.09 m{sup 3}/kg dry material, respectively, a higher methane yield than that previously reported for municipal solid waste. Variability in methane production rates were observed over time and between reactors. Based on our laboratory data, annual methane emissions from burial of cattle mortalities in the United States could total 1.6 Tg CO{sub 2} equivalents. Although this represents less than 1% of total emissions produced by the agricultural sector in 2009, greenhouse gas emissions from animal carcass burial may be significant if disposal of swine and poultry carcasses is also considered.« less

75 FR 75059 - Mandatory Reporting of Greenhouse Gases: Injection and Geologic Sequestration of Carbon Dioxide

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-01

... monitoring will achieve detection and quantification of CO 2 in the event surface leakage occurs. The UIC... leakage detection monitoring system or technical specifications should also be described in the MRV plan... of injected CO 2 or from another cause (e.g. natural variability). The MRV plan leakage detection and...

Emission of methane and carbon dioxide and earthworm survival during composting of pharmaceutical sludge and spent mycelia.

PubMed

Majumdar, Deepanjan; Patel, Jigisha; Bhatt, Neha; Desai, Priyanka

2006-03-01

Emissions of methane (CH4) and carbon dioxide (CO2) from spent mycelia of the mold Penicilium notatum and sludge from the effluent treatment facility (ETPS) of a pharmaceutical industry were estimated twice during a two-week composting before vermicomposting. These wastes are dumped in landfills or sometimes used in agricultural fields and no reports are available on their greenhouse gas producing potentials. The solid wastes contained appreciable organic carbon and nitrogen while very high Fe, Mn and Zn were found in ETPS only. Pure wastes did not support germination of Vigna radiata L. while mixing soil with ETPS and spent mycelia at the ratios of 12:1 and 14:1 led to 80% and 50% germination, respectively. The wastes were mixed with cowdung at the ratios of 1:1, 1:3 and 3:1 for composting. Carbon dioxide emissions were always significantly higher than CH4 emissions from all the treatments due to prevalence of aerobic condition during composting. From some treatments, CH4 emissions increased with time, indicating increasing activity of anaerobic bacteria in the waste mixtures. Methane emissions ranged from 21.6 to 231.7 microg m(-2) day(-1) while CO2 emissions were greater than thousand times at 39.8-894.8 mg m(-2) day(-1). The amount of C emitted as CH4-C and CO2-C from ranged from 0.007% to 0.081% of total C composted. Cowdung emitted highest CH4 followed by spent mycelia and ETPS while ETPS emitted more CO2 than spent mycelia but lesser than cowdung. Global warming potential of emitted CH4 was found to be in the range of 10.6-27.7 mg-CO2-equivalent on a 20-year time horizon. The results suggest that pharmaceutical wastes can be an important source of CH4 and CO2 during composting or any other stockpiling under suitable moisture conditions. The waste mixtures were found not suitable for vermicomposting after two weeks composting and earthworms did not survive long in the mixtures.

Elevated carbon dioxide accelerates the spatial turnover of soil microbial communities

DOE PAGES

Deng, Ye; He, Zhili; Xiong, Jinbo; ...

2015-10-23

Although elevated CO 2 (eCO 2) significantly affects the -diversity, composition, function, interaction and dynamics of soil microbial communities at the local scale, little is known about eCO 2 impacts on the geographic distribution of micro-organisms regionally or globally. Here, we examined the -diversity of 110 soil microbial communities across six free air CO 2 enrichment (FACE) experimental sites using a high-throughput functional gene array. The -diversity of soil microbial communities was significantly (P<0.05) correlated with geographic distance under both CO 2 conditions, but declined significantly (P<0.05) faster at eCO 2 with a slope of -0.0250 than at ambient COmore » 2 (aCO 2) with a slope of -0.0231 although it varied within each individual site, indicating that the spatial turnover rate of soil microbial communities was accelerated under eCO 2 at a larger geographic scale (e.g. regionally). Both distance and soil properties significantly (P<0.05) contributed to the observed microbial -diversity. Furthermore, this study provides new hypotheses for further understanding their assembly mechanisms that may be especially important as global CO 2 continues to increase.« less

Elevated carbon dioxide accelerates the spatial turnover of soil microbial communities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Ye; He, Zhili; Xiong, Jinbo

Although elevated CO 2 (eCO 2) significantly affects the -diversity, composition, function, interaction and dynamics of soil microbial communities at the local scale, little is known about eCO 2 impacts on the geographic distribution of micro-organisms regionally or globally. Here, we examined the -diversity of 110 soil microbial communities across six free air CO 2 enrichment (FACE) experimental sites using a high-throughput functional gene array. The -diversity of soil microbial communities was significantly (P<0.05) correlated with geographic distance under both CO 2 conditions, but declined significantly (P<0.05) faster at eCO 2 with a slope of -0.0250 than at ambient COmore » 2 (aCO 2) with a slope of -0.0231 although it varied within each individual site, indicating that the spatial turnover rate of soil microbial communities was accelerated under eCO 2 at a larger geographic scale (e.g. regionally). Both distance and soil properties significantly (P<0.05) contributed to the observed microbial -diversity. Furthermore, this study provides new hypotheses for further understanding their assembly mechanisms that may be especially important as global CO 2 continues to increase.« less

Land use and management change under climate change adaptation and mitigation strategies: a U.S. case study

USGS Publications Warehouse

Mu, Jianhong E.; Wein, Anne; McCarl, Bruce

2015-01-01

We examine the effects of crop management adaptation and climate mitigation strategies on land use and land management, plus on related environmental and economic outcomes. We find that crop management adaptation (e.g. crop mix, new species) increases Greenhouse gas (GHG) emissions by 1.7 % under a more severe climate projection while a carbon price reduces total forest and agriculture GHG annual flux by 15 % and 9 %, respectively. This shows that trade-offs are likely between mitigation and adaptation. Climate change coupled with crop management adaptation has small and mostly negative effects on welfare; mitigation, which is implemented as a carbon price starting at $15 per metric ton carbon dioxide (CO2) equivalent with a 5 % annual increase rate, bolsters welfare carbon payments. When both crop management adaptation and carbon price are implemented the effects of the latter dominates.

Palm oil mill effluent treatment and utilization to ensure the sustainability of palm oil industries.

PubMed

Hasanudin, U; Sugiharto, R; Haryanto, A; Setiadi, T; Fujie, K

2015-01-01

The purpose of this study was to evaluate the current condition of palm oil mill effluent (POME) treatment and utilization and to propose alternative scenarios to improve the sustainability of palm oil industries. The research was conducted through field survey at some palm oil mills in Indonesia, in which different waste management systems were used. Laboratory experiment was also carried out using a 5 m(3) pilot-scale wet anaerobic digester. Currently, POME is treated through anaerobic digestion without or with methane capture followed by utilization of treated POME as liquid fertilizer or further treatment (aerobic process) to fulfill the wastewater quality standard. A methane capturing system was estimated to successfully produce renewable energy of about 25.4-40.7 kWh/ton of fresh fruit bunches (FFBs) and reduce greenhouse gas (GHG) emissions by about 109.41-175.35 kgCO2e/tonFFB (CO2e: carbon dioxide equivalent). Utilization of treated POME as liquid fertilizer increased FFB production by about 13%. A palm oil mill with 45 ton FFB/hour capacity has potential to generate about 0.95-1.52 MW of electricity. Coupling the POME-based biogas digester and anaerobic co-composting of empty fruit bunches (EFBs) is capable of adding another 0.93 MW. The utilization of POME and EFB not only increases the added value of POME and EFB by producing renewable energy, compost, and liquid fertilizer, but also lowers environmental burden.

Mobile source CO2 mitigation through smart growth development and vehicle fleet hybridization.

PubMed

Stone, Brian; Mednick, Adam C; Holloway, Tracey; Spak, Scott N

2009-03-15

This paper presents the results of a study on the effectiveness of smart growth development patterns and vehicle fleet hybridization in reducing mobile source emissions of carbon dioxide (CO2) across 11 major metropolitan regions of the Midwestern U.S. over a 50-year period. Through the integration of a vehicle travel activity modeling framework developed by researchers atthe Oak Ridge National Laboratory with small area population projections, we model mobile source emissions of CO2 associated with alternative land development and technology change scenarios between 2000 and 2050. Our findings suggest that under an aggressive smart growth scenario, growth in emissions expected to occur under a business as usual scenario is reduced by 34%, while the full dissemination of hybrid-electric vehicles throughout the light vehicle fleet is found to offset the expected growth in emissions by 97%. Our results further suggest that high levels of urban densification could achieve reductions in 2050 CO2 emissions equivalent to those attainable through the full dissemination of hybrid-electric vehicle technologies.

Deep peat warming increases surface methane and carbon dioxide emissions in a black spruce-dominated ombrotrophic bog.

PubMed

Gill, Allison L; Giasson, Marc-André; Yu, Rieka; Finzi, Adrien C

2017-12-01

Boreal peatlands contain approximately 500 Pg carbon (C) in the soil, emit globally significant quantities of methane (CH 4 ), and are highly sensitive to climate change. Warming associated with global climate change is likely to increase the rate of the temperature-sensitive processes that decompose stored organic carbon and release carbon dioxide (CO 2 ) and CH 4 . Variation in the temperature sensitivity of CO 2 and CH 4 production and increased peat aerobicity due to enhanced growing-season evapotranspiration may alter the nature of peatland trace gas emission. As CH 4 is a powerful greenhouse gas with 34 times the warming potential of CO 2 , it is critical to understand how factors associated with global change will influence surface CO 2 and CH 4 fluxes. Here, we leverage the Spruce and Peatland Responses Under Changing Environments (SPRUCE) climate change manipulation experiment to understand the impact of a 0-9°C gradient in deep belowground warming ("Deep Peat Heat", DPH) on peat surface CO 2 and CH 4 fluxes. We find that DPH treatments increased both CO 2 and CH 4 emission. Methane production was more sensitive to warming than CO 2 production, decreasing the C-CO 2 :C-CH 4 of the respired carbon. Methane production is dominated by hydrogenotrophic methanogenesis but deep peat warming increased the δ 13 C of CH 4 suggesting an increasing contribution of acetoclastic methanogenesis to total CH 4 production with warming. Although the total quantity of C emitted from the SPRUCE Bog as CH 4 is <2%, CH 4 represents >50% of seasonal C emissions in the highest-warming treatments when adjusted for CO 2 equivalents on a 100-year timescale. These results suggest that warming in boreal regions may increase CH 4 emissions from peatlands and result in a positive feedback to ongoing warming. © 2017 John Wiley & Sons Ltd.

A fast invariant imbedding method for multiple scattering calculations and an application to equivalent widths of CO2 lines on Venus

NASA Technical Reports Server (NTRS)

Sato, M.; Kawabata, K.; Hansen, J. E.

1977-01-01

The invariant imbedding method considered is based on an equation which describes the change in the reflected radiation when an optically thin layer is added to the top of the atmosphere. The equation is used to treat the problem of reflection from a planetary atmosphere as an initial value problem. A fast method is discussed for the solution of the invariant imbedding equation. The speed and accuracy of the new method are illustrated by comparing it with the doubling program published by Hansen and Travis (1974). Computations are performed of the equivalent widths of carbon dioxide absorption lines in solar radiation reflected by Venus for several models of the planetary atmosphere.

Design and development of a new generation of UV-visible-light-driven nanosized codoped titanium dioxide photocatalysts and biocides/sporocides, and environmental applications

NASA Astrophysics Data System (ADS)

Hamal, Dambar B.

For solar environmental remediation, a new generation of nanosized (< 10 nm) titanium dioxide photocatalysts codoped with metals and nonmetals, or metals only were prepared by the xero-gel and aero-gel methods. For silver or cobalt-based xero-gel titanium dioxide photocatalysts, photoactivities tests revealed that codoping of titanium dioxide with a metal (1% Ag or 2% Co) and nonmetals (carbon and sulfur) is necessary to achieve high-activities for acetaldehyde degradation under visible light (wavelength > 420 nm). It was concluded that high visible-light-activities for acetaldehyde degradation over codoped titanium dioxide were attributed to an interplay of anatase crystallinity, high-surface area, reduced band-gap (< 3.0 eV), uniform dispersion of doped metal ions, and suppressed recombination rate of photogenerated electronhole pairs. Moreover, the nature and amount of codoped metals play a significant role in visible-light-induced photocatalysis. Metals (Al, Ga, and In) doped/codoped titanium dioxide photocatalysts were prepared by the aero-gel method. The photocatalytic studies showed that activities of metal doped/codoped photocatalysts under UV light (wavelength < 400 nm) were found to be dependent on pollutants. Indium demonstrated beneficial effects in both textural and photocatalytic properties. Gallium and indium codoped titanium dioxide photocatalysts displayed even better performance in the CO oxidation reaction under UV light. Notably, titanium dioxide codoped with Ga, In, and Pt, exhibited unique photoactivities for the CO oxidation under both UV and visible light irradiation, indicating that this system could have promise for the water-gas shift reaction for hydrogen production. Silver-based nanostructured titanium dioxide samples were developed for killing human pathogens (Escherichia coli cells and Bacillus subtilis spores). Biocidal tests revealed that silver, carbon, and sulfur codoped titanium dioxide nanoparticles (< 10 nm) possess very strong antimicrobial actions on both E. coli (logarithmic kill > 8) and B. subtilis spores (logarithmic kill > 5) for 30 minute exposures in dark conditions compared with Degussa P25. It was believed that the carbon and sulfur codoped titanium dioxide support and Ag species acted synergistically during deactivation of both E. coli and B. subtilis spores. Thus, titanium dioxide codoped with silver, carbon, sulfur can serve as a multifunctional generic biocide and a visible-light-active photocatalyst.

Elevated atmospheric carbon dioxide concentrations promote ant tending of aphids.

PubMed

Kremer, Jenni M M; Nooten, Sabine S; Cook, James M; Ryalls, James M W; Barton, Craig V M; Johnson, Scott N

2018-04-27

Animal mutualisms, which involve beneficial interactions between individuals of different species, are common in nature. Insect-insect mutualism, for example, is widely regarded as a keystone ecological interaction. Some mutualisms are anticipated to be modified by climate change, but the focus has largely been on plant-microbe and plant-animal mutualisms rather than those between animals. Ant-aphid mutualisms, whereby ants tend aphids to harvest their honeydew excretions and, in return, provide protection for the aphids, are widespread. The mutualism is heavily influenced by the quality and quantity of honeydew produced by aphids, which is directly affected by host plant quality. As predicted increases in concentrations of atmospheric carbon dioxide (eCO 2 ) are widely reported to affect plant nutritional chemistry, this may also alter honeydew quality and hence the nature of ant-aphid mutualisms. Using glasshouse chambers and field-based open-top chambers, we determined the effect of eCO 2 on the growth and nutritional quality (foliar amino acids) of lucerne (Medicago sativa). We determined how cowpea aphid (Aphis craccivora) populations and honeydew production were impacted when feeding on such plants and how this affected the tending behaviour of ants (Iridomyrmex sp.). eCO 2 stimulated plant growth but decreased concentrations of foliar amino acids by 29% and 14% on aphid-infested plants and aphid-free plants, respectively. Despite the deterioration in host plant quality under eCO 2 , aphids maintained performance and populations were unchanged by eCO 2 . Aphids induced higher concentrations of amino acids (glutamine, asparagine, glutamic acid and aspartic acid) important for endosymbiont-mediated synthesis of essential amino acids. Aphids feeding under eCO 2 also produced over three times more honeydew than aphids feeding under ambient CO 2 , suggesting they were imbibing more phloem sap at eCO 2 . The frequency of ant tending of aphids more than doubled in response to eCO 2 . To our knowledge, this is the first study to demonstrate the effects of atmospheric change on an ant-aphid mutualism. In particular, these results highlight how impending changes to concentrations of atmospheric CO 2 may alter mutualistic behaviour between animals. These could include positive impacts, as reported here, shifts from mutualism to antagonism, partner switches and mutualism abandonment. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

Carbon Dioxide Reduction Technology Trade Study

NASA Technical Reports Server (NTRS)

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

2011-01-01

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.

TES/Aura L2 Carbon Dioxide (CO2) Nadir V7 (TL2CO2N)

Atmospheric Science Data Center

2018-01-18

... TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N) News:  TES News Join TES News List Project ... TES Order Tool Parameters:  Earth Science Atmosphere Atmospheric Chemistry/Carbon and Hydrocarbon Compounds ...

Anaerobic digestion of agricultural and other substrates--implications for greenhouse gas emissions.

PubMed

Pucker, J; Jungmeier, G; Siegl, S; Pötsch, E M

2013-06-01

The greenhouse gas (GHG) emissions, expressed in carbon dioxide equivalents (CO2-eq), of different Austrian biogas systems were analyzed and evaluated using life-cycle assessment (LCA) as part of a national project. Six commercial biogas plants were investigated and the analysis included the complete process chain: viz., the production and collection of substrates, the fermentation of the substrates in the biogas plant, the upgrading of biogas to biomethane (if applicable) and the use of the biogas or biomethane for heat and electricity or as transportation fuel. Furthermore, the LCA included the GHG emissions of construction, operation and dismantling of the major components involved in the process chain, as well as the use of by-products (e.g. fermentation residues used as fertilizers). All of the biogas systems reduced GHG emissions (in CO2-eq) compared with fossil reference systems. The potential for GHG reduction of the individual biogas systems varied between 60% and 100%. Type of feedstock and its reference use, agricultural practices, coverage of storage tanks for fermentation residues, methane leakage at the combined heat and power plant unit and the proportion of energy used as heat were identified as key factors influencing the GHG emissions of anaerobic digestion processes.

Nickel-coated Aluminum Particles: A Promising Fuel for Mars Missions

NASA Technical Reports Server (NTRS)

Shafirovich, Evgeny; Varma, Arvind

2004-01-01

Combustion of metals in carbon dioxide is a promising source of energy for propulsion on Mars. This approach is based on the ability of some metals (e.g. Mg, Al) to burn in CO2 atmosphere and suggests use of the Martian carbon dioxide as an oxidizer in jet or rocket engines. Analysis shows that CO2/metal propulsion will reduce significantly the mass of propellant transported from Earth for long-range mobility on Mars and sample return missions. Recent calculations for the near-term missions indicate that a 200-kg ballistic hopper with CO2/metal rocket engines and a CO2 acquisition unit can perform 10-15 flights on Mars with the total range of 10-15 km, i.e. fulfill the exploration program typically assigned for a rover. Magnesium is currently recognized as a candidate fuel for such engines owing to easy ignition and fast burning in CO2. Aluminum may be more advantageous if a method for reducing its ignition temperature is found. Coating it by nickel is one such method. It is known that a thin nickel layer of nickel on the surface of aluminum particles can prevent their agglomeration and simultaneously facilitate their ignition, thus increasing the efficiency of aluminized propellants.

Sensitivity Studies for Space-based Measurement of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

NASA Technical Reports Server (NTRS)

Mao, Jianping; Kawa, S. Randolph

2003-01-01

A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 microns. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the radiance signal or sensitivity to CO2 change near the surface is not significantly diminished even in the presence of aerosols and/or thin cirrus clouds in the atmosphere; (c) the modification of sunlight path length by scattering of aerosols and cirrus clouds could lead to large systematic errors in the retrieval; therefore, ancillary aerosol/cirrus cloud data are important to reduce retrieval errors; (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature; (e) the atmospheric path length, over which the CO2 absorption occurs, must be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

Methane production as key to the greenhouse gas budget of thawing permafrost on climate relevant time scales

NASA Astrophysics Data System (ADS)

Knoblauch, C.; Beer, C.; Liebner, S.; Schütt, A.; Grigoriev, M.; Pfeiffer, E. M.

2017-12-01

Permafrost in circum-arctic soils stores as much carbon as the global atmosphere. Permafrost thaw liberates organic matter, which is mineralized by microorganisms to carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) may form a positive feedback to atmospheric CO2 and CH4 concentrations and accelerate climate change. The microbial formation of CH4, which has 28 to 45 times the global warming potential (GWP) of CO2 (100 years time scale), requires anoxic conditions. Current studies indicate that permafrost thaw at the bottom of well drained (oxic) soils cause a higher formation of GHGs than in water saturated (anoxic) soils since more CO2 is formed under oxic conditions and only small amounts of CH4 are formed from permafrost organic matter under anoxic conditions. Here we show through 7-year laboratory incubations and molecular analysis of Siberian permafrost that low CH4 production from permafrost organic matter is due to the lack of active methanogens. Equal amounts of permafrost organic carbon are mineralized to CO2 and CH4 under anoxic conditions after an active methanogenic community has established. Field measurements demonstrate that recently thawed permafrost organic matter is a substantial source for CH4 if primed with surface soil. An organic carbon decomposition model, calibrated with the collected long-term incubation data, predicts a higher loss of permafrost carbon under oxic conditions but a twice as high production of CO2-C equivalents under anoxic conditions when considering a GWP of 28 for CH4. Combining these model results with observed permafrost carbon profile data, up-scaled carbon stocks and thaw depth projections suggests a global formation of 3 - 10 Pg CO2-C from thawing permafrost in oxic soils compared to 0.2 - 0.6 Pg CO2-C and 0.2- 0.8 Pg CH4-C in anoxic soils until 2100. However, based on CO2-C equivalents the GHG production in anoxic soils (2 - 9 Pg CO2-C equivalents) is similar to those in oxic soils. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils and emphasize the importance of CH4 production in thawing permafrost.

The cardiopulmonary exercise test grey zone; optimising fitness stratification by application of critical difference.

PubMed

Rose, G A; Davies, R G; Davison, G W; Adams, R A; Williams, I M; Lewis, M H; Appadurai, I R; Bailey, D M

2018-06-01

Cardiorespiratory fitness can inform patient care, although to what extent natural variation in CRF influences clinical practice remains to be established. We calculated natural variation for cardiopulmonary exercise test (CPET) metrics, which may have implications for fitness stratification. In a two-armed experiment, critical difference comprising analytical imprecision and biological variation was calculated for cardiorespiratory fitness and thus defined the magnitude of change required to claim a clinically meaningful change. This metric was retrospectively applied to 213 patients scheduled for colorectal surgery. These patients underwent CPET and the potential for misclassification of fitness was calculated. We created a model with boundaries inclusive of natural variation [critical difference applied to oxygen uptake at anaerobic threshold (V˙O 2 -AT): 11 ml O 2  kg -1  min -1 , peak oxygen uptake (V˙O 2 peak): 16 ml O 2  kg -1  min -1 , and ventilatory equivalent for carbon dioxide at AT (V̇ E /V̇CO 2 -AT): 36]. The critical difference for V˙O 2 -AT, V˙O 2 peak, and V˙ E /V˙CO 2 -AT was 19%, 13%, and 10%, respectively, resulting in false negative and false positive rates of up to 28% and 32% for unfit patients. Our model identified boundaries for unfit and fit patients: AT <9.2 and ≥13.6 ml O 2  kg -1  min -1 , V˙O 2 peak <14.2 and ≥18.3 ml kg -1  min -1 , V˙ E /V˙CO 2 -AT ≥40.1 and <32.7, between which an area of indeterminate-fitness was established. With natural variation considered, up to 60% of patients presented with indeterminate-fitness. These findings support a reappraisal of current clinical interpretation of cardiorespiratory fitness highlighting the potential for incorrect fitness stratification when natural variation is not accounted for. Copyright © 2018 British Journal of Anaesthesia. All rights reserved.

Ocean Acidification: Hands-On Experiments to Explore the Causes and Consequences

ERIC Educational Resources Information Center

Bruno, Barbara C.; Tice, Kimberly A.; Puniwai, Noelani; Achilles, Kate

2011-01-01

Ocean acidification is one of the most serious environmental issues facing the planet (e.g., Doney 2006; Guinotte and Fabry 2009). It is caused by excess carbon dioxide (CO[subscript 2]) in the atmosphere. Human activities such as burning fossil fuels put CO[subscript 2] and other heat-trapping gases into the atmosphere, which causes the Earth's…

Optimization of an Atmospheric Carbon Source for Extremophile Cyanobacteria

NASA Astrophysics Data System (ADS)

Beaubien, Courtney

This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.

Distinct responses of soil microbial communities to elevated CO2 and O3 in a soybean agro-ecosystem

PubMed Central

He, Zhili; Xiong, Jinbo; Kent, Angela D; Deng, Ye; Xue, Kai; Wang, Gejiao; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong

2014-01-01

The concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have been rising due to human activities. However, little is known about how such increases influence soil microbial communities. We hypothesized that elevated CO2 (eCO2) and elevated O3 (eO3) would significantly affect the functional composition, structure and metabolic potential of soil microbial communities, and that various functional groups would respond to such atmospheric changes differentially. To test these hypotheses, we analyzed 96 soil samples from a soybean free-air CO2 enrichment (SoyFACE) experimental site using a comprehensive functional gene microarray (GeoChip 3.0). The results showed the overall functional composition and structure of soil microbial communities shifted under eCO2, eO3 or eCO2+eO3. Key functional genes involved in carbon fixation and degradation, nitrogen fixation, denitrification and methane metabolism were stimulated under eCO2, whereas those involved in N fixation, denitrification and N mineralization were suppressed under eO3, resulting in the fact that the abundance of some eO3-supressed genes was promoted to ambient, or eCO2-induced levels by the interaction of eCO2+eO3. Such effects appeared distinct for each treatment and significantly correlated with soil properties and soybean yield. Overall, our analysis suggests possible mechanisms of microbial responses to global atmospheric change factors through the stimulation of C and N cycling by eCO2, the inhibition of N functional processes by eO3 and the interaction by eCO2 and eO3. This study provides new insights into our understanding of microbial functional processes in response to global atmospheric change in soybean agro-ecosystems. PMID:24108327

Optimization of supercritical carbon dioxide extraction of Piper Betel Linn leaves oil and total phenolic content

NASA Astrophysics Data System (ADS)

Aziz, A. H. A.; Yunus, M. A. C.; Arsad, N. H.; Lee, N. Y.; Idham, Z.; Razak, A. Q. A.

2016-11-01

Supercritical Carbon Dioxide (SC-CO2) Extraction was applied to extract piper betel linn leaves. The piper betel leaves oil was used antioxidant, anti-diabetic, anticancer and antistroke. The aim of this study was to optimize the conditions of pressure, temperature and flowrate for oil yield and total phenolic content. The operational conditions of SC-CO2 studied were pressure (10, 20, 30 MPa), temperature (40, 60, 80 °C) and flowrate carbon dioxide (4, 6, 8 mL/min). The constant parameters were average particle size and extraction regime, 355pm and 3.5 hours respectively. First order polynomial expression was used to express the extracted oil while second order polynomial expression was used to express the total phenolic content and the both results were satisfactory. The best conditions to maximize the total extraction oil yields and total phenolic content were 30 MPa, 80 °C and 4.42 mL/min leading to 7.32% of oil and 29.72 MPa, 67.53 °C and 7.98 mL/min leading to 845.085 mg GAE/g sample. In terms of optimum condition with high extraction yield and high total phenolic content in the extracts, the best operating conditions were 30 MPa, 78 °C and 8 mL/min with 7.05% yield and 791.709 mg gallic acid equivalent (GAE)/g sample. The most dominant condition for extraction of oil yield and phenolic content were pressure and CO2 flowrate. The results show a good fit to the proposed model and the optimal conditions obtained were within the experimental range with the value of R2 was 96.13% for percentage yield and 98.52% for total phenolic content.

Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.

PubMed

Fukuoka, Yoshiyuki; Iihoshi, Masaaki; Nazunin, Juhelee Tuba; Abe, Daijiro; Fukuba, Yoshiyuki

2017-01-01

Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency), breath-by-breath ventilation (V̇E) and gas exchange (CO2 output (V̇CO2) and O2 uptake (V̇O2)) responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min). The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW) was significantly greater than that during sinusoidal cycling (SC), and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward) and muscle afferent feedback.

Environmental Consequences of Invasive Species: Greenhouse Gas Emissions of Insecticide Use and the Role of Biological Control in Reducing Emissions

PubMed Central

Heimpel, George E.; Yang, Yi; Hill, Jason D.; Ragsdale, David W.

2013-01-01

Greenhouse gas emissions associated with pesticide applications against invasive species constitute an environmental cost of species invasions that has remained largely unrecognized. Here we calculate greenhouse gas emissions associated with the invasion of an agricultural pest from Asia to North America. The soybean aphid, Aphis glycines, was first discovered in North America in 2000, and has led to a substantial increase in insecticide use in soybeans. We estimate that the manufacture, transport, and application of insecticides against soybean aphid results in approximately 10.6 kg of carbon dioxide (CO2) equivalent greenhouse gasses being emitted per hectare of soybeans treated. Given the acreage sprayed, this has led to annual emissions of between 6 and 40 million kg of CO2 equivalent greenhouse gasses in the United States since the invasion of soybean aphid, depending on pest population size. Emissions would be higher were it not for the development of a threshold aphid density below which farmers are advised not to spray. Without a threshold, farmers tend to spray preemptively and the threshold allows farmers to take advantage of naturally occurring biological control of the soybean aphid, which can be substantial. We find that adoption of the soybean aphid economic threshold can lead to emission reductions of approximately 300 million kg of CO2 equivalent greenhouse gases per year in the United States. Previous studies have documented that biological control agents such as lady beetles are capable of suppressing aphid densities below this threshold in over half of the soybean acreage in the U.S. Given the acreages involved this suggests that biological control results in annual emission reductions of over 200 million kg of CO2 equivalents. These analyses show how interactions between invasive species and organisms that suppress them can interact to affect greenhouse gas emissions. PMID:23977273

Environmental consequences of invasive species: greenhouse gas emissions of insecticide use and the role of biological control in reducing emissions.

PubMed

Heimpel, George E; Yang, Yi; Hill, Jason D; Ragsdale, David W

2013-01-01

Greenhouse gas emissions associated with pesticide applications against invasive species constitute an environmental cost of species invasions that has remained largely unrecognized. Here we calculate greenhouse gas emissions associated with the invasion of an agricultural pest from Asia to North America. The soybean aphid, Aphis glycines, was first discovered in North America in 2000, and has led to a substantial increase in insecticide use in soybeans. We estimate that the manufacture, transport, and application of insecticides against soybean aphid results in approximately 10.6 kg of carbon dioxide (CO2) equivalent greenhouse gasses being emitted per hectare of soybeans treated. Given the acreage sprayed, this has led to annual emissions of between 6 and 40 million kg of CO2 equivalent greenhouse gasses in the United States since the invasion of soybean aphid, depending on pest population size. Emissions would be higher were it not for the development of a threshold aphid density below which farmers are advised not to spray. Without a threshold, farmers tend to spray preemptively and the threshold allows farmers to take advantage of naturally occurring biological control of the soybean aphid, which can be substantial. We find that adoption of the soybean aphid economic threshold can lead to emission reductions of approximately 300 million kg of CO2 equivalent greenhouse gases per year in the United States. Previous studies have documented that biological control agents such as lady beetles are capable of suppressing aphid densities below this threshold in over half of the soybean acreage in the U.S. Given the acreages involved this suggests that biological control results in annual emission reductions of over 200 million kg of CO2 equivalents. These analyses show how interactions between invasive species and organisms that suppress them can interact to affect greenhouse gas emissions.

Efficient Hydrogen-Dependent Carbon Dioxide Reduction by Escherichia coli.

PubMed

Roger, Magali; Brown, Fraser; Gabrielli, William; Sargent, Frank

2018-01-08

Hydrogen-dependent reduction of carbon dioxide to formic acid offers a promising route to greenhouse gas sequestration, carbon abatement technologies, hydrogen transport and storage, and the sustainable generation of renewable chemical feedstocks [1]. The most common approach to performing direct hydrogenation of CO 2 to formate is to use chemical catalysts in homogeneous or heterogeneous reactions [2]. An alternative approach is to use the ability of living organisms to perform this reaction biologically. However, although CO 2 fixation pathways are widely distributed in nature, only a few enzymes have been described that have the ability to perform the direct hydrogenation of CO 2 [3-5]. The formate hydrogenlyase (FHL) enzyme from Escherichia coli normally oxidizes formic acid to carbon dioxide and couples that reaction directly to the reduction of protons to molecular hydrogen [6]. In this work, the reverse reaction of FHL is unlocked. It is established that FHL can operate as a highly efficient hydrogen-dependent carbon dioxide reductase when gaseous CO 2 and H 2 are placed under pressure (up to 10 bar). Using intact whole cells, the pressurized system was observed to rapidly convert 100% of gaseous CO 2 to formic acid, and >500 mM formate was observed to accumulate in solution. Harnessing the reverse reaction has the potential to allow the versatile E. coli system to be employed as an exciting new carbon capture technology or as a cell factory dedicated to formic acid production, which is a commodity in itself as well as a feedstock for the synthesis of other valued chemicals. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Photosynthesis and carbon allocation are both important predictors of genotype productivity responses to elevated CO2 in Eucalyptus camaldulensis.

PubMed

Aspinwall, Michael J; Blackman, Chris J; de Dios, Víctor Resco; Busch, Florian A; Rymer, Paul D; Loik, Michael E; Drake, John E; Pfautsch, Sebastian; Smith, Renee A; Tjoelker, Mark G; Tissue, David T

2018-05-08

Intraspecific variation in biomass production responses to elevated atmospheric carbon dioxide (eCO2) could influence tree species' ecological and evolutionary responses to climate change. However, the physiological mechanisms underlying genotypic variation in responsiveness to eCO2 remain poorly understood. In this study, we grew 17 Eucalyptus camaldulensis Dehnh. subsp. camaldulensis genotypes (representing provenances from four different climates) under ambient atmospheric CO2 and eCO2. We tested whether genotype leaf-scale photosynthetic and whole-tree carbon (C) allocation responses to eCO2 were predictive of genotype biomass production responses to eCO2. Averaged across genotypes, growth at eCO2 increased in situ leaf net photosynthesis (Anet) (29%) and leaf starch concentrations (37%). Growth at eCO2 reduced the maximum carboxylation capacity of Rubisco (-4%) and leaf nitrogen per unit area (Narea, -6%), but Narea calculated on a total non-structural carbohydrate-free basis was similar between treatments. Growth at eCO2 also increased biomass production and altered C allocation by reducing leaf area ratio (-11%) and stem mass fraction (SMF, -9%), and increasing leaf mass area (18%) and leaf mass fraction (5%). Overall, we found few significant CO2 × provenance or CO2 × genotype (within provenance) interactions. However, genotypes that showed the largest increases in total dry mass at eCO2 had larger increases in root mass fraction (with larger decreases in SMF) and photosynthetic nitrogen-use efficiency (PNUE) with CO2 enrichment. These results indicate that genetic differences in PNUE and carbon sink utilization (in roots) are both important predictors of tree productivity responsiveness to eCO2.

Emissions of carbon monoxide and carbon dioxide from uncompressed and pelletized biomass fuel burning in typical household stoves in China

NASA Astrophysics Data System (ADS)

Wei, Wen; Zhang, Wei; Hu, Dan; Ou, Langbo; Tong, Yindong; Shen, Guofeng; Shen, Huizhong; Wang, Xuejun

2012-09-01

Carbon dioxide (CO2) and carbon monoxide (CO) impact climate change and human health. The uncertainties in emissions inventories of CO2 and CO are primarily due to the large variation in measured emissions factors (EFs), especially to the lack of EFs from developing countries. China's goals of reducing CO2 emissions require a maximum utilization of biomass fuels. Pelletized biomass fuels are well suited for the residential biomass market, providing possibilities of more automated and optimized systems with higher modified combustion efficiency (MCE) and less products from incomplete combustion. However, EFs of CO2 and CO from pellet biomass fuels are seldom reported, and a comparison to conventional uncompressed biomass fuels has never been conducted. Therefore, the objectives of this study were to experimentally determine the CO2 and CO EFs from uncompressed biomass (i.e., firewood and crop residues) and biomass pellets (i.e., pine wood pellet and corn straw pellet) under real residential applications and to compare the influences of fuel properties and combustion conditions on CO2 and CO emissions from the two types of biomass fuels. For the uncompressed biomass examples, the CO2 and CO EFs were 1649.4 ± 35.2 g kg-1 and 47.8 ± 8.9 g kg-1, respectively, for firewood and 1503.2 ± 148.5 g kg-1 and 52.0 ± 14.2 g kg-1, respectively, for crop residues. For the pellet biomass fuel examples, the CO2 and CO EFs were 1708.0 ± 3.8 g kg-1 and 4.4 ± 2.4 g kg-1, respectively, for pellet pine and 1552.1 ± 16.3 g kg-1 and 17.9 ± 10.2 g kg-1, respectively, for pellet corn. In rural China areas during 2007, firewood and crop residue burning produced 721.7 and 23.4 million tons of CO2 and CO, respectively.

Recent enlightening strategies for co2 capture: a review

NASA Astrophysics Data System (ADS)

Yuan, Peng; Qiu, Ziyang; Liu, Jia

2017-05-01

The global climate change has seriously affected the survival and prosperity of mankind, where greenhouse effect owing to atmospheric carbon dioxide (CO2) enrichment is a great cause. Accordingly, a series of down-to-earth measures need to be implemented urgently to control the output of CO2. As CO2 capture appears as a core issue in developing low-carbon economy, this review provides a comprehensive introduction of recent CO2 capture technologies used in power plants or other industries. Strategies for CO2 capture, e.g. pre-combustion, post-combustion and oxyfuel combustion, are covered in this article. Another enlightening technology for CO2 capture based on fluidized beds is intensively discussed.

On the development of a methodology for extensive in-situ and continuous atmospheric CO2 monitoring

NASA Astrophysics Data System (ADS)

Wang, K.; Chang, S.; Jhang, T.

2010-12-01

Carbon dioxide is recognized as the dominating greenhouse gas contributing to anthropogenic global warming. Stringent controls on carbon dioxide emissions are viewed as necessary steps in controlling atmospheric carbon dioxide concentrations. From the view point of policy making, regulation of carbon dioxide emissions and its monitoring are keys to the success of stringent controls on carbon dioxide emissions. Especially, extensive atmospheric CO2 monitoring is a crucial step to ensure that CO2 emission control strategies are closely followed. In this work we develop a methodology that enables reliable and accurate in-situ and continuous atmospheric CO2 monitoring for policy making. The methodology comprises the use of gas filter correlation (GFC) instrument for in-situ CO2 monitoring, the use of CO2 working standards accompanying the continuous measurements, and the use of NOAA WMO CO2 standard gases for calibrating the working standards. The use of GFC instruments enables 1-second data sampling frequency with the interference of water vapor removed from added dryer. The CO2 measurements are conducted in the following timed and cycled manner: zero CO2 measurement, two standard CO2 gases measurements, and ambient air measurements. The standard CO2 gases are calibrated again NOAA WMO CO2 standards. The methodology is used in indoor CO2 measurements in a commercial office (about 120 people working inside), ambient CO2 measurements, and installed in a fleet of in-service commercial cargo ships for monitoring CO2 over global marine boundary layer. These measurements demonstrate our method is reliable, accurate, and traceable to NOAA WMO CO2 standards. The portability of the instrument and the working standards make the method readily applied for large-scale and extensive CO2 measurements.

21 CFR 868.2480 - Cutaneous carbon dioxide (PcCO2) monitor.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cutaneous carbon dioxide (PcCO2) monitor. 868.2480 Section 868.2480 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2480 Cutaneous carbon dioxide (PcCO2) monitor. (a) Identification. A...

Corrosion Behavior of FBR Structural Materials in High Temperature Supercritical Carbon Dioxide

NASA Astrophysics Data System (ADS)

Furukawa, Tomohiro; Inagaki, Yoshiyuki; Aritomi, Masanori

A key problem in the application of a supercritical carbon dioxide (CO2) turbine cycle to a fast breeder reactor (FBR) is the corrosion of structural material by supercritical CO2 at high temperature. In this study, corrosion test of high-chromium martensitic steel (12Cr-steel) and FBR grade type 316 stainless steel (316FR), which are candidate materials for FBRs, were performed at 400-600°C in supercritical CO2 pressurized at 20MPa. Corrosion due to the high temperature oxidation in exposed surface was measured up to approximately 2000h in both steels. In the case of 12Cr-steel, the weight gain showed parabolic growth with exposure time at each temperature. The oxidation coefficient could be estimated by the Arrhenius function. The specimens were covered by two successive oxide layers, an Fe-Cr-O layer (inside) and an Fe-O layer (outside). A partial thin oxide diffusion layer appeared between the base metal and the Fe-Cr-O layer. The corrosion behavior was equivalent to that in supercritical CO2 at 10MPa, and no effects of CO2 pressure on oxidation were observed in this study. In the case of 316FR specimens, the weight gain was significantly lower than that of 12Cr-steel. Dependency of neither temperature nor exposed time on oxidation was not observed, and the value of all tested specimens was within 2g/m2. Nodule shape oxides which consisted of two structures, Fe-Cr-O and Fe-O were observed on the surface of the 316FR specimen. Carburizing, known as a factor in the occurrence of breakaway corrosion and/or the degradation of ductility, was observed on the surface of both steels.

Benefits of Leapfrogging to Superefficiency and Low Global Warming Potential Refrigerants in Room Air Conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Nihar; Wei, Max; Letschert, Virginie

2015-10-01

Hydrofluorocarbons (HFCs) emitted from uses such as refrigerants and thermal insulating foam, are now the fastest growing greenhouse gases (GHGs), with global warming potentials (GWP) thousands of times higher than carbon dioxide (CO2). Because of the short lifetime of these molecules in the atmosphere, mitigating the amount of these short-lived climate pollutants (SLCPs) provides a faster path to climate change mitigation than control of CO2 alone. This has led to proposals from Africa, Europe, India, Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) to phase-down high-GWP HFCs. Simultaneously, energymore » efficiency market transformation programs such as standards, labeling and incentive programs are endeavoring to improve the energy efficiency for refrigeration and air conditioning equipment to provide life cycle cost, energy, GHG, and peak load savings. In this paper we provide an estimate of the magnitude of such GHG and peak electric load savings potential, for room air conditioning, if the refrigerant transition and energy efficiency improvement policies are implemented either separately or in parallel. We find that implementing HFC refrigerant transition and energy efficiency improvement policies in parallel for room air conditioning, roughly doubles the benefit of either policy implemented separately. We estimate that shifting the 2030 world stock of room air conditioners from the low efficiency technology using high-GWP refrigerants to higher efficiency technology and low-GWP refrigerants in parallel would save between 340-790 gigawatts (GW) of peak load globally, which is roughly equivalent to avoiding 680-1550 peak power plants of 500MW each. This would save 0.85 GT/year annually in China equivalent to over 8 Three Gorges dams and over 0.32 GT/year annually in India equivalent to roughly twice India’s 100GW solar mission target. While there is some uncertainty associated with emissions and growth projections, moving to efficient room air conditioning (~30% more efficient than current technology) in parallel with low-GWP refrigerants in room air conditioning could avoid up to ~25 billion tonnes of CO2 in 2030, ~33 billion in 2040, and ~40 billion in 2050, i.e. cumulative savings up to 98 billion tonnes of CO2 by 2050. Therefore, superefficient room ACs using low-GWP refrigerants merit serious consideration to maximize peak load reduction and GHG savings.« less

Rain events decrease boreal peatland net CO2 uptake through reduced light availability.

PubMed

Nijp, Jelmer J; Limpens, Juul; Metselaar, Klaas; Peichl, Matthias; Nilsson, Mats B; van der Zee, Sjoerd E A T M; Berendse, Frank

2015-06-01

Boreal peatlands store large amounts of carbon, reflecting their important role in the global carbon cycle. The short-term exchange and the long-term storage of atmospheric carbon dioxide (CO2 ) in these ecosystems are closely associated with the permanently wet surface conditions and are susceptible to drought. Especially, the single most important peat forming plant genus, Sphagnum, depends heavily on surface wetness for its primary production. Changes in rainfall patterns are expected to affect surface wetness, but how this transient rewetting affects net ecosystem exchange of CO2 (NEE) remains unknown. This study explores how the timing and characteristics of rain events during photosynthetic active periods, that is daytime, affect peatland NEE and whether rain event associated changes in environmental conditions modify this response (e.g. water table, radiation, vapour pressure deficit, temperature). We analysed an 11-year time series of half-hourly eddy covariance and meteorological measurements from Degerö Stormyr, a boreal peatland in northern Sweden. Our results show that daytime rain events systematically decreased the sink strength of peatlands for atmospheric CO2 . The decrease was best explained by rain associated reduction in light, rather than by rain characteristics or drought length. An average daytime growing season rain event reduced net ecosystem CO2 uptake by 0.23-0.54 gC m(-2) . On an annual basis, this reduction of net CO2 uptake corresponds to 24% of the annual net CO2 uptake (NEE) of the study site, equivalent to a 4.4% reduction of gross primary production (GPP) during the growing season. We conclude that reduced light availability associated with rain events is more important in explaining the NEE response to rain events than rain characteristics and changes in water availability. This suggests that peatland CO2 uptake is highly sensitive to changes in cloud cover formation and to altered rainfall regimes, a process hitherto largely ignored. © 2015 John Wiley & Sons Ltd.

The Martian ocean: First acid, then alkaline

NASA Technical Reports Server (NTRS)

Schaefer, M. W.

1992-01-01

In Mars' distant past, carbon dioxide and water may have been plentiful. Values of total outgassed CO2 from several to about 10 bar are consistent with present knowledge, and this amount of CO2 implies an amount of water outgassed equal to an equivalent depth of 500 to 1000 m. It is quite reasonable, therefore, to envision an early Mars in which there was a body or bodies of liquid water, perhaps in the northern plains, and a dense carbon dioxide atmosphere. Under such conditions, the pH of the water will be low, due to the dissolution of carbon dioxide in the water to form carbonic acid. This acidic water is capable of weathering the available rock quite intensely, particularly because this rock is likely to be heavily fractured (from meteorite bombardment) or even consist of fine particles (such as pyroclastic deposits). As time goes on, however, the carbon dioxide atmosphere will rapidly pass through the ocean to form carbonate deposits. As the density of the atmosphere decreases, so will the flux of carbonic acid into the ocean. Without this input of carbonic acid, the effect of the dissolved weathering products will be to increase the pH of the water. The ocean will then become alkaline. To study this process, I have developed a geochemical cycle model for the atmosphere-hydrosphere-regolith system of Mars. The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success. This method is capable of elegantly handling the interactions between the simultaneous chemical reactions needed to understand such a system.

Effect of carbon dioxide on the thermal degradation of lignocellulosic biomass.

PubMed

Kwon, Eilhann E; Jeon, Eui-Chan; Castaldi, Marco J; Jeon, Young Jae

2013-09-17

Using biomass as a renewable energy source via currently available thermochemical processes (i.e., pyrolysis and gasification) is environmentally advantageous owing to its intrinsic carbon neutrality. Developing methodologies to enhance the thermal efficiency of these proven technologies is therefore imperative. This study aimed to investigate the use of CO2 as a reaction medium to increase not only thermal efficiency but also environmental benefit. The influence of CO2 on thermochemical processes at a fundamental level was experimentally validated with the main constituents of biomass (i.e., cellulose and xylan) to avoid complexities arising from the heterogeneous matrix of biomass. For instance, gaseous products including H2, CH4, and CO were substantially enhanced in the presence of CO2 because CO2 expedited thermal cracking behavior (i.e., 200-1000%). This behavior was then universally observed in our case study with real biomass (i.e., corn stover) during pyrolysis and steam gasification. However, further study is urgently needed to optimize these experimental findings.

Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system

NASA Astrophysics Data System (ADS)

Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

2016-08-01

Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment.

Assessment of agglomeration, co-sedimentation and trophic transfer of titanium dioxide nanoparticles in a laboratory-scale predator-prey model system

PubMed Central

Gupta, Govind Sharan; Kumar, Ashutosh; Shanker, Rishi; Dhawan, Alok

2016-01-01

Nano titanium dioxide (nTiO2) is the most abundantly released engineered nanomaterial (ENM) in aquatic environments. Therefore, it is prudent to assess its fate and its effects on lower trophic-level organisms in the aquatic food chain. A predator-and-prey-based laboratory microcosm was established using Paramecium caudatum and Escherichia coli to evaluate the effects of nTiO2. The surface interaction of nTiO2 with E. coli significantly increased after the addition of Paramecium into the microcosm. This interaction favoured the hetero-agglomeration and co-sedimentation of nTiO2. The extent of nTiO2 agglomeration under experimental conditions was as follows: combined E. coli and Paramecium > Paramecium only > E. coli only > without E. coli or Paramecium. An increase in nTiO2 internalisation in Paramecium cells was also observed in the presence or absence of E. coli cells. These interactions and nTiO2 internalisation in Paramecium cells induced statistically significant (p < 0.05) effects on growth and the bacterial ingestion rate at 24 h. These findings provide new insights into the fate of nTiO2 in the presence of bacterial-ciliate interactions in the aquatic environment. PMID:27530102

Climatic role of terrestrial ecosystem under elevated CO2 : a bottom-up greenhouse gases budget.

PubMed

Liu, Shuwei; Ji, Cheng; Wang, Cong; Chen, Jie; Jin, Yaguo; Zou, Ziheng; Li, Shuqing; Niu, Shuli; Zou, Jianwen

2018-05-07

The net balance of greenhouse gas (GHG) exchanges between terrestrial ecosystems and the atmosphere under elevated atmospheric carbon dioxide (CO 2 ) remains poorly understood. Here, we synthesise 1655 measurements from 169 published studies to assess GHGs budget of terrestrial ecosystems under elevated CO 2 . We show that elevated CO 2 significantly stimulates plant C pool (NPP) by 20%, soil CO 2 fluxes by 24%, and methane (CH 4 ) fluxes by 34% from rice paddies and by 12% from natural wetlands, while it slightly decreases CH 4 uptake of upland soils by 3.8%. Elevated CO 2 causes insignificant increases in soil nitrous oxide (N 2 O) fluxes (4.6%), soil organic C (4.3%) and N (3.6%) pools. The elevated CO 2 -induced increase in GHG emissions may decline with CO 2 enrichment levels. An elevated CO 2 -induced rise in soil CH 4 and N 2 O emissions (2.76 Pg CO 2 -equivalent year -1 ) could negate soil C enrichment (2.42 Pg CO 2 year -1 ) or reduce mitigation potential of terrestrial net ecosystem production by as much as 69% (NEP, 3.99 Pg CO 2 year -1 ) under elevated CO 2 . Our analysis highlights that the capacity of terrestrial ecosystems to act as a sink to slow climate warming under elevated CO 2 might have been largely offset by its induced increases in soil GHGs source strength. © 2018 John Wiley & Sons Ltd/CNRS.

Geoengineering with Charged Droplets

NASA Astrophysics Data System (ADS)

Gokturk, H.

2011-12-01

Water molecules in a droplet are held together by intermolecular forces generated by hydrogen bonding which has a bonding energy of only about 0.2 eV. One can create a more rugged droplet by using an ion as a condensation nucleus. In that case, water molecules are held together by the interaction between the ion and the dipole moments of the water molecules surrounding the ion, in addition to any hydrogen bonding. In this research, properties of such charged droplets were investigated using first principle quantum mechanical calculations. A molecule which exhibits positive electron affinity is a good candidate to serve as the ionic condensation nucleus, because addition of an electron to such a molecule creates an energetically more stable state than the neutral molecule. A good example is the oxygen molecule (O2) where energy of O2 negative (O2-) ion is lower than that of the neutral O2 by about 0.5 eV. Examples of other molecules which have positive electron affinity include ozone (O3), nitrogen dioxide (NO2) and sulfur oxides (SOx, x=1-3). Atomic models used in the calculations consisted of a negative ion of one of the molecules mentioned above surrounded by water molecules. Calculations were performed using the DFT method with B3LYP hybrid functional and Pople type basis sets with polarization and diffuse functions. Energy of interaction between O2- ion and the water molecule was found to be ~0.7 eV. This energy is an order of magnitude greater than the thermal energy of even the highest temperatures encountered in the atmosphere. Once created, charged rugged droplets can survive in hot and dry climates where they can be utilized to create humidity and precipitation. The ion which serves as the nucleus of the droplet can attract not only water molecules but also other dipolar gases in the atmosphere. Such dipolar gases include industrial pollutants, for example nitrogen dioxide (NO2) or sulfur dioxide (SO2). Energy of interaction between O2- ion and pollutant molecules was calculated to be ~0.5 eV for NO2 and ~0.9 eV for SO2. These values are comparable to that of water, hence charged droplets have the potential to serve as scavengers of pollutants in the atmosphere. The charged droplet can also interact with quadrupolar gases depending on the charge distribution of the gas. A quadrupole of interest is carbon dioxide (CO2) where oxygens are slightly negative and carbon is slightly positive in a neutral molecule. When CO2 is in the vicinity of a negative ion, the carbon atom gets attracted to the ion, whereas oxygens are repelled from it. This interaction distorts the linear geometry of CO2, turning it into a small dipole. Energy of interaction between O2- ion and CO2 was calculated to be ~0.3 eV which is smaller than those of the above mentioned dipoles, but still significantly greater than the typical thermal energy at 25 C (~0.03 eV). One can expect the diffusion of atmospheric CO2 into the droplets to be enhanced due to the charge. Hence such droplets can help capture the CO2 in the atmosphere and sequester it simply as rain. Charged droplets can be created using electrical,optical, thermal or other means. A method which utilizes solar energy will be described in the presentation.

Bacterial Synthesis of Unusual Sulfonamide and Sulfone Antibiotics by Flavoenzyme-Mediated Sulfur Dioxide Capture.

PubMed

Baunach, Martin; Ding, Ling; Willing, Karsten; Hertweck, Christian

2015-11-02

Sulfa drugs, such as sulfonilamide and dapsone, are classical antibiotics that have been in clinical use worldwide. Despite the relatively simple architectures, practically no natural products are known to feature such aromatic sulfonamide or diarylsulfone substructures. We report the unexpected discovery of three fully unprecedented, sulfonyl-bridged alkaloid dimers (sulfadixiamycins A-C) from recombinant Streptomyces species harboring the entire xiamycin biosynthesis gene cluster. Sulfadixiamycins exhibit moderate antimycobacterial activities and potent antibiotic activities even against multidrug-resistant bacteria. Gene inactivation, complementation, and biotransformation experiments revealed that a flavin-dependent enzyme (XiaH) plays a key role in sulfadixiamycin biosynthesis. XiaH mediates a radical-based, three-component reaction involving two equivalents of xiamycin and sulfur dioxide, which is reminiscent of radical styrene/SO2 copolymerization. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Patterns in CH4 and CO2 concentrations across boreal rivers: Major drivers and implications for fluvial greenhouse emissions under climate change scenarios.

PubMed

Campeau, Audrey; Del Giorgio, Paul A

2014-04-01

It is now widely accepted that boreal rivers and streams are regionally significant sources of carbon dioxide (CO2), yet their role as methane (CH4) emitters, as well as the sensitivity of these greenhouse gas (GHG) emissions to climate change, are still largely undefined. In this study, we explore the large-scale patterns of fluvial CO2 and CH4 partial pressure (pCO2 , pCH4) and gas exchange (k) relative to a set of key, climate-sensitive river variables across 46 streams and rivers in two distinct boreal landscapes of Northern Québec. We use the resulting models to determine the direction and magnitude of C-gas emissions from these boreal fluvial networks under scenarios of climate change. River pCO2 and pCH4 were positively correlated, although the latter was two orders of magnitude more variable. We provide evidence that in-stream metabolism strongly influences the dynamics of surface water pCO2 and pCH4 , but whereas pCO2 is not influenced by temperature in the surveyed streams and rivers, pCH4 appears to be strongly temperature-dependent. The major predictors of ambient gas concentrations and exchange were water temperature, velocity, and DOC, and the resulting models indicate that total GHG emissions (C-CO2 equivalent) from the entire network may increase between by 13 to 68% under plausible scenarios of climate change over the next 50 years. These predicted increases in fluvial GHG emissions are mostly driven by a steep increase in the contribution of CH4 (from 36 to over 50% of total CO2 -equivalents). The current role of boreal fluvial networks as major landscape sources of C is thus likely to expand, mainly driven by large increases in fluvial CH4 emissions. © 2013 John Wiley & Sons Ltd.

Producing liquid fuels from biomass

NASA Astrophysics Data System (ADS)

Solantausta, Yrjo; Gust, Steven

The aim of this survey was to compare, on techno-economic criteria, alternatives of producing liquid fuels from indigenous raw materials in Finland. Another aim was to compare methods under development and prepare a proposal for steering research related to this field. Process concepts were prepared for a number of alternatives, as well as analogous balances and production and investment cost assessments for these balances. Carbon dioxide emissions of the alternatives and the price of CO2 reduction were also studied. All the alternatives for producing liquid fuels from indigenous raw materials are utmost unprofitable. There are great differences between the alternatives. While the production cost of ethanol is 6 to 9 times higher than the market value of the product, the equivalent ratio for substitute fuel oil produced from peat by pyrolysis is 3 to 4. However, it should be borne in mind that the technical uncertainties related to the alternatives are of different magnitude. Production of ethanol from barley is of commercial technology, while biomass pyrolysis is still under development. If the aim is to reach smaller carbon dioxide emissions by using liquid biofuels, the most favorable alternative is pyrolysis oil produced from wood. Fuels produced from cultivated biomass are more expensive ways of reducing CO2 emissions. Their potential of reducing CO2 emissions in Finland is insignificant. Integration of liquid fuel production to some other production line is more profitable.

Feasibility of atmospheric methane removal using methanotrophic biotrickling filters.

PubMed

Yoon, Sukhwan; Carey, Jeffrey N; Semrau, Jeremy D

2009-07-01

Methane is a potent greenhouse gas with a global warming potential ~23 times that of carbon dioxide. Here, we describe the modeling of a biotrickling filtration system composed of methane-consuming bacteria, i.e., methanotrophs, to assess the utility of these systems in removing methane from the atmosphere. Model results indicate that assuming the global average atmospheric concentration of methane, 1.7 ppmv, methane removal is ineffective using these methanotrophic biofilters as the methane concentration is too low to enable cell survival. If the concentration is increased to 500-6,000 ppmv, however, similar to that found above landfills and in concentrated animal feeding operations (factory farms), 4.98-35.7 tons of methane can be removed per biofilter per year assuming biotrickling filters of typical size (3.66 m in diameter and 11.5 m in height). Using reported ranges of capital, operational, and maintenance costs, the cost of the equivalent ton of CO(2) removal using these systems is $90-$910 ($2,070-$20,900 per ton of methane), depending on the influent concentration of methane and if heating is required. The use of methanotrophic biofilters for controlling methane emissions is technically feasible and, provided that either the costs of biofilter construction and operation are reduced or the value of CO(2) credits is increased, can also be economically attractive.

[Preliminary assessment of the potential of biochar technology in mitigating the greenhouse effect in China].

PubMed

Jiang, Zhi-Xiang; Zheng, Hao; Li, Feng-Min; Wang, Zhen-Yu

2013-06-01

The production of biochar by pyrolysis and its application to soil can sequester the CO2 which was absorbed by plants from atmosphere into soil, in addition it can also bring multiple benefits for agriculture production. On the basis of the available potential survey of the biomass residues from agriculture and forestry section, life cycle assessment was employed to quantify the potential of biochar technology in mitigation of greenhouse gases in our country. The results showed: In China, the amount of available biomass resource was 6.04 x 10(8) t every year and its net greenhouse effect potential was 5.32 x 10(8) t CO(2e) (CO(2e): CO2 equivalent), which was equivalent to 0.88 t CO(2e) for every ton biomass. The greatest of contributor to the total potential was plant carbon sequestration in soil as the form of biochar which accounts for 73.94%, followed by production of renewable energy and its percentage was 23.85%. In summary, production of biochar from agriculture and forestry biomass residues had a significant potential for our country to struggle with the pressure of greenhouse gas emission.

Comparison of buried soil sensors, surface chambers and above ground measurements of carbon dioxide fluxes

USDA-ARS?s Scientific Manuscript database

Soil carbon dioxide (CO2) flux is an important component of the terrestrial carbon cycle. Accurate measurements of soil CO2 flux aids determinations of carbon budgets. In this study, we investigated soil CO2 fluxes with time and depth and above ground CO2 fluxes in a bare field. CO2 concentrations w...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

...) The use of linearizing circuits is permitted. (c) The minimum water rejection ratio (maximum CO 2... shall be 5000:1. (e) Zero suppression. Various techniques of zero suppression may be used to increase...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

...) The use of linearizing circuits is permitted. (c) The minimum water rejection ratio (maximum CO 2... shall be 5000:1. (e) Zero suppression. Various techniques of zero suppression may be used to increase...

A new method for estimating carbon dioxide emissions from transportation at fine spatial scales

PubMed Central

Shu, Yuqin; Reams, Margaret

2016-01-01

Detailed estimates of carbon dioxide (CO2) emissions at fine spatial scales are useful to both modelers and decision makers who are faced with the problem of global warming and climate change. Globally, transport related emissions of carbon dioxide are growing. This letter presents a new method based on the volume-preserving principle in the areal interpolation literature to disaggregate transportation-related CO2 emission estimates from the county-level scale to a 1 km2 grid scale. The proposed volume-preserving interpolation (VPI) method, together with the distance-decay principle, were used to derive emission weights for each grid based on its proximity to highways, roads, railroads, waterways, and airports. The total CO2 emission value summed from the grids within a county is made to be equal to the original county-level estimate, thus enforcing the volume-preserving property. The method was applied to downscale the transportation-related CO2 emission values by county (i.e. parish) for the state of Louisiana into 1 km2 grids. The results reveal a more realistic spatial pattern of CO2 emission from transportation, which can be used to identify the emission ‘hot spots’. Of the four highest transportation-related CO2 emission hotspots in Louisiana, high-emission grids literally covered the entire East Baton Rouge Parish and Orleans Parish, whereas CO2 emission in Jefferson Parish (New Orleans suburb) and Caddo Parish (city of Shreveport) were more unevenly distributed. We argue that the new method is sound in principle, flexible in practice, and the resultant estimates are more accurate than previous gridding approaches. PMID:26997973

Carbon dioxide separation with a two-dimensional polymer membrane.

PubMed

Schrier, Joshua

2012-07-25

Carbon dioxide gas separation is important for many environmental and energy applications. Molecular dynamics simulations are used to characterize a two-dimensional hydrocarbon polymer, PG-ES1, that uses a combination of surface adsorption and narrow pores to separate carbon dioxide from nitrogen, oxygen, and methane gases. The CO2 permeance is 3 × 10(5) gas permeation units (GPU). The CO2/N2 selectivity is 60, and the CO2/CH4 selectivity exceeds 500. The combination of high CO2 permeance and selectivity surpasses all known materials, enabling low-cost postcombustion CO2 capture, utilization of landfill gas, and horticulture applications.

The influence of graded degrees of chronic hypercapnia on the acute carbon dioxide titration curve

PubMed Central

Goldstein, Marc B.; Gennari, F. John; Schwartz, William B.

1971-01-01

Studies were carried out to determine the influence of the chronic level of arterial carbon dioxide tension upon the buffering response to acute changes in arterial carbon dioxide tension. After chronic adaptation to six levels of arterial CO2 tension, ranging between 35 and 110 mm Hg, unanesthetized dogs underwent acute whole body CO2 titrations. In each instance a linear relationship was observed between the plasma hydrogen ion concentration and the arterial carbon dioxide tension. Because of this linear relationship, it has been convenient to compare the acute buffering responses among dogs in terms of the slope, dH+/dPaco2. With increasing chronic hypercapnia there was a decrease in this slope, i.e. an improvement in buffer capacity, which is expressed by the equation dH+/dPaco2=-0.005 (Paco2)chronic + 0.95. In effect, the ability to defend pH during acute titration virtually doubled as chronic Paco2 increased from 35 to 110 mm Hg. The change in slope, dH+/dPaco2, was the consequence of the following two factors: the rise in plasma bicarbonate concentration which occurs with chronic hypercapnia of increasing severity, and the greater change in bicarbonate concentration which occurred during the acute CO2 titration in the animals with more severe chronic hypercapnia. These findings demonstrate the importance of the acid-base status before acute titration in determining the character of the carbon dioxide titration curve. They also suggest that a quantitative definition of the interplay between acute and chronic hypercapnia in man should assist in the rational analysis of acid-base disorders in chronic pulmonary insufficiency. PMID:5543876

Methane and nitrous oxide emissions from livestock agriculture in 16 local administrative districts of Korea.

PubMed

Ji, Eun Sook; Park, Kyu-Hyun

2012-12-01

This study was conducted to evaluate methane (CH4) and nitrous oxide (N2O) emissions from livestock agriculture in 16 local administrative districts of Korea from 1990 to 2030. National Inventory Report used 3 yr averaged livestock population but this study used 1 yr livestock population to find yearly emission fluctuations. Extrapolation of the livestock population from 1990 to 2009 was used to forecast future livestock population from 2010 to 2030. Past (yr 1990 to 2009) and forecasted (yr 2010 to 2030) averaged enteric CH4 emissions and CH4 and N2O emissions from manure treatment were estimated. In the section of enteric fermentation, forecasted average CH4 emissions from 16 local administrative districts were estimated to increase by 4%-114% compared to that of the past except for Daejeon (-63%), Seoul (-36%) and Gyeonggi (-7%). As for manure treatment, forecasted average CH4 emissions from the 16 local administrative districts were estimated to increase by 3%-124% compared to past average except for Daejeon (-77%), Busan (-60%), Gwangju (-48%) and Seoul (-8%). For manure treatment, forecasted average N2O emissions from the 16 local administrative districts were estimated to increase by 10%-153% compared to past average CH4 emissions except for Daejeon (-60%), Seoul (-4.0%), and Gwangju (-0.2%). With the carbon dioxide equivalent emissions (CO2-Eq), forecasted average CO2-Eq from the 16 local administrative districts were estimated to increase by 31%-120% compared to past average CH4 emissions except Daejeon (-65%), Seoul (-24%), Busan (-18%), Gwangju (-8%) and Gyeonggi (-1%). The decreased CO2-Eq from 5 local administrative districts was only 34 kt, which was insignificantly small compared to increase of 2,809 kt from other 11 local administrative districts. Annual growth rates of enteric CH4 emissions, CH4 and N2O emissions from manure management in Korea from 1990 to 2009 were 1.7%, 2.6%, and 3.2%, respectively. The annual growth rate of total CO2-Eq was 2.2%. Efforts by the local administrative offices to improve the accuracy of activity data are essential to improve GHG inventories. Direct measurements of GHG emissions from enteric fermentation and manure treatment systems will further enhance the accuracy of the GHG data. (Key Words: Greenhouse Gas, Methane, Nitrous Oxide, Carbon Dioxide Equivalent Emission, Climate Change).

Application of end-tidal carbon dioxide monitoring via distal gas samples in ventilated neonates.

PubMed

Jin, Ziying; Yang, Maoying; Lin, Ru; Huang, Wenfang; Wang, Jiangmei; Hu, Zhiyong; Shu, Qiang

2017-08-01

Previous research has suggested correlations between the end-tidal partial pressure of carbon dioxide (P ET CO 2 ) and the partial pressure of arterial carbon dioxide (PaCO 2 ) in mechanically ventilated patients, but both the relationship between P ET CO 2 and PaCO 2 and whether P ET CO 2 accurately reflects PaCO 2 in neonates and infants are still controversial. This study evaluated remote sampling of P ET CO 2 via an epidural catheter within an endotracheal tube to determine the procedure's clinical safety and efficacy in the perioperative management of neonates. Abdominal surgery was performed under general anesthesia in 86 full-term newborns (age 1-30 days, weight 2.55-4.0 kg, American Society of Anesthesiologists class I or II). The infants were divided into 2 groups (n = 43 each), and carbon dioxide (CO 2 ) gas samples were collected either from the conventional position (the proximal end) or a modified position (the distal end) of the epidural catheter. The P ET CO 2 measured with the new method was significantly higher than that measured with the traditional method, and the difference between P ET CO 2 and PaCO 2 was also reduced. The accuracy of P ET CO 2 measured increased from 78.7% to 91.5% when the modified sampling method was used. The moderate correlation between P ET CO 2 and PaCO 2 by traditional measurement was 0.596, which significantly increased to 0.960 in the modified sampling group. Thus, the P ET CO 2 value was closer to that of PaCO 2 . P ET CO 2 detected via modified carbon dioxide monitoring had a better accuracy and correlation with PaCO 2 in neonates. Copyright © 2017. Published by Elsevier B.V.

Can Producing Oil Store Carbon? Greenhouse Gas Footprint of CO2EOR, Offshore North Sea.

PubMed

Stewart, R Jamie; Haszeldine, R Stuart

2015-05-05

Carbon dioxide enhanced oil recovery (CO2EOR) is a proven and available technology used to produce incremental oil from depleted fields while permanently storing large tonnages of injected CO2. Although this technology has been used successfully onshore in North America and Europe, there are currently no CO2EOR projects in the United Kingdom. Here, we examine whether offshore CO2EOR can store more CO2 than onshore projects traditionally have and whether CO2 storage can offset additional emissions produced through offshore operations and incremental oil production. Using a high-level Life Cycle system approach, we find that the largest contribution to offshore emissions is from flaring or venting of reproduced CH4 and CO2. These can already be greatly reduced by regulation. If CO2 injection is continued after oil production has been optimized, then offshore CO2EOR has the potential to be carbon negative--even when emissions from refining, transport, and combustion of produced crude oil are included. The carbon intensity of oil produced can be just 0.056-0.062 tCO2e/bbl if flaring/venting is reduced by regulation. This compares against conventional Saudi oil 0.040 tCO2e/bbl or mined shale oil >0.300 tCO2e/bbl.

Evaluation and characterization of the methane-carbon dioxide decomposition reaction

NASA Technical Reports Server (NTRS)

Davenport, R. J.; Schubert, F. H.; Shumar, J. W.; Steenson, T. S.

1975-01-01

A program was conducted to evaluate and characterize the carbon dioxide-methane (CO2-CH4) decomposition reaction, i.e., CO2 + CH4 = 2C + 2H2O. The primary objective was to determine the feasibility of applying this reaction at low temperatures as a technique for recovering the oxygen (O2) remaining in the CO2 which exits mixed with CH4 from a Sabatier CO2 reduction subsystem (as part of an air revitalization system of a manned spacecraft). A test unit was designed, fabricated, and assembled for characterizing the performance of various catalysts for the reaction and ultraviolet activation of the CH4 and CO2. The reactor included in the test unit was designed to have sufficient capacity to evaluate catalyst charges of up to 76 g (0.17 lb). The test stand contained the necessary instrumentation and controls to obtain the data required to characterize the performance of the catalysts and sensitizers tested: flow control and measurement, temperature control and measurement, product and inlet gas analysis, and pressure measurement. A product assurance program was performed implementing the concepts of quality control and safety into the program effort.

Assessing the impact on chronic disease of incorporating the societal cost of greenhouse gases into the price of food: an econometric and comparative risk assessment modelling study

PubMed Central

Briggs, Adam D M; Kehlbacher, Ariane; Tiffin, Richard; Garnett, Tara; Rayner, Mike; Scarborough, Peter

2013-01-01

Objectives To model the impact on chronic disease of a tax on UK food and drink that internalises the wider costs to society of greenhouse gas (GHG) emissions and to estimate the potential revenue. Design An econometric and comparative risk assessment modelling study. Setting The UK. Participants The UK adult population. Interventions Two tax scenarios are modelled: (A) a tax of £2.72/tonne carbon dioxide equivalents (tCO2e)/100 g product applied to all food and drink groups with above average GHG emissions. (B) As with scenario (A) but food groups with emissions below average are subsidised to create a tax neutral scenario. Outcome measures Primary outcomes are change in UK population mortality from chronic diseases following the implementation of each taxation strategy, the change in the UK GHG emissions and the predicted revenue. Secondary outcomes are the changes to the micronutrient composition of the UK diet. Results Scenario (A) results in 7770 (95% credible intervals 7150 to 8390) deaths averted and a reduction in GHG emissions of 18 683 (14 665to 22 889) ktCO2e/year. Estimated annual revenue is £2.02 (£1.98 to £2.06) billion. Scenario (B) results in 2685 (1966 to 3402) extra deaths and a reduction in GHG emissions of 15 228 (11 245to 19 492) ktCO2e/year. Conclusions Incorporating the societal cost of GHG into the price of foods could save 7770 lives in the UK each year, reduce food-related GHG emissions and generate substantial tax revenue. The revenue neutral scenario (B) demonstrates that sustainability and health goals are not always aligned. Future work should focus on investigating the health impact by population subgroup and on designing fiscal strategies to promote both sustainable and healthy diets. PMID:24154517

Methods and apparatus for measuring small leaks from carbon dioxide sequestration facilities

DOEpatents

Nelson, Jr., David D.; Herndon, Scott C.

2018-01-02

In one embodiment, a CO.sub.2 leak detection instrument detects leaks from a site (e.g., a CO.sub.2 sequestration facility) using rapid concentration measurements of CO.sub.2, O.sub.2 and optionally water concentration that are achieved, for example, using laser spectroscopy (e.g. direct absorption laser spectroscopy). Water vapor in the sample gas may not be removed, or only partially removed. The sample gas may be collected using a multiplexed inlet assembly from a plurality of locations. CO.sub.2 and O.sub.2 concentrations may be corrected based on the water concentration. A resulting dataset of the CO.sub.2 and O.sub.2 concentrations is analyzed over time intervals to detect any changes in CO.sub.2 concentration that are not anti-correlated with O.sub.2 concentration, and to identify a potential CO.sub.2 leak in response thereto. The analysis may include determining eddy covariance flux measurements of sub-surface potential carbon.

Chapter 2: Climate, disturbance, and vulnerability to vegetation change in the Northwest Forest Plan Area

Treesearch

Matthew J. Reilly; Thomas A.  Spies; Ramona Butz Littell; John B. . Kim

2018-01-01

Climate change is expected to alter the composition, structure, and function of forested ecosystems in the United States (Vose et al. 2012). Increases in atmospheric concentrations of greenhouse gases (e.g., carbon dioxide [CO2]) and temperature, as well as altered precipitation and disturbance regimes (e.g., fire, insects, pathogens, and windstorms), are expected to...

CO2 Compressor Requirements for Integration of Space Station Carbon Dioxide Removal and Carbon Dioxide Reduction Assemblies

NASA Technical Reports Server (NTRS)

Jeng, Frank F.; Lewis, John F.; Graf, John; LaFuse, Sharon; Nicholson, Leonard S. (Technical Monitor)

1999-01-01

This paper describes the analysis on integration requirements, CO2 compressor in particular, for integration of Carbon Dioxide Removal Assembly (CDRA) and CO2 Reduction Assembly (CRA) as a part of the Node 3 project previously conducted at JSC/NASA. A system analysis on the volume and operation pressure range of the CO2 accumulator was conducted. The hardware and operational configurations of the CO2 compressor were developed. The performance and interface requirements of the compressor were specified. An existing Four-Bed Molecular Sieve CO2 removal computer model was modified into a CDRA model and used in analyzing the requirements of the CDRA CO2 compressor. This CDRA model was also used in analyzing CDRA operation parameters that dictate CO2 pump sizing. Strategy for the pump activation was also analyzed.

W.A. Parish Post Combustion CO 2 Capture and Sequestration Project Final Public Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armpriester, Anthony

The Petra Nova Project is a commercial scale post-combustion carbon dioxide capture project that is being developed by a joint venture between NRG Energy (NRG) and JX Nippon Oil and Gas Exploration (JX). The project is designed to separate and capture carbon dioxide from an existing coal-fired unit's flue gas slipstream at NRG's W.A. Parish Generation Station located southwest of Houston, Texas. The captured carbon dioxide will be transported by pipeline and injected into the West Ranch oil field to boost oil production. The project, which is partially funded by financial assistance from the U.S. Department of Energy will usemore » Mitsubishi Heavy Industries of America, Inc.'s Kansai Mitsubishi Carbon Dioxide Recovery (KM-CDR(R)) advanced amine-based carbon dioxide absorption technology to treat and capture at least 90% of the carbon dioxide from a 240 megawatt equivalent flue gas slipstream off of Unit 8 at W.A. Parish. The project will capture approximately 5,000 tons of carbon dioxide per day or 1.5 million tons per year that Unit 8 would otherwise emit, representing the largest commercial scale deployment of post-combustion carbon dioxide capture at a coal power plant to date. The joint venture issued full notice to proceed in July 2014 and when complete, the project is expected to be the world's largest post-combustion carbon dioxide capture facility on an existing coal plant. The detailed engineering is sufficiently complete to prepare and issue the Final Public Design Report.« less

Migration of carbon dioxide included micro-nano bubble water in porous media and its monitoring

NASA Astrophysics Data System (ADS)

Takemura, T.; Hamamoto, S.; Suzuki, K.; Koichi, O.

2017-12-01

The distributed CO2 storage is the small scale storage and its located near the emission areas. In the distributed CO2 storage, the CO2 is neutralized by sediment and underground water in the subsurface region (300-500m depth). Carbon dioxide (CO2) included micro-nano bubbles is one approach in neutralizing CO2 and sediments by increasing CO2 volume per unit volume of water and accelerating the chemical reaction. In order to design underground treatment for CO2 gas in the subsurface, it is required to elucidate the behavior of CO2 included micro-nano bubbles in the water. In this study, we carried out laboratory experiment using the soil tank, and measure the amount of leakage of CO2 gas at the surface. In addition, the process of migration of carbon dioxide included micro-nano bubble was monitored by the nondestructive method, wave velocity and resistivity.

Emotional Avoidance and Panicogenic Responding to a Biological Challenge Procedure

ERIC Educational Resources Information Center

Karekla, Maria; Forsyth, John P.; Kelly, Megan M.

2004-01-01

Healthy undergraduates high (n = 27) and low (n = 27) in experiential avoidance underwent twelve 20 s inhalations of 20% carbon dioxide-enriched air, while physiological (e.g., skin conductance, heart rate, EMG, and end-tidal CO[subscript 2]) and subjective (e.g., subjective units of distress, evaluative ratings, number and severity of panic…

Virus infection mediates the effects of elevated CO2 on plants and vectors.

PubMed

Trębicki, Piotr; Vandegeer, Rebecca K; Bosque-Pérez, Nilsa A; Powell, Kevin S; Dader, Beatriz; Freeman, Angela J; Yen, Alan L; Fitzgerald, Glenn J; Luck, Jo E

2016-03-04

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

Virus infection mediates the effects of elevated CO2 on plants and vectors

PubMed Central

Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-01-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production. PMID:26941044

Virus infection mediates the effects of elevated CO2 on plants and vectors

NASA Astrophysics Data System (ADS)

Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-03-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

Briefing on geological sequestration

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media – primarily saline formations, depleted or nearly depleted oil and gas...

Sensitivity Studies for Space-based Measurements of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

NASA Technical Reports Server (NTRS)

Mao, Jianping; Kawa, S. Randolph

2003-01-01

A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 micron. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the effects of other interfering constituents, such as water vapor, aerosols and cirrus clouds, on the radiance are significant but the overall effects of the modification of light path length on total back-to-space radiance sensitivity to CO2 change are minor for general cases, which means that generally the total column CO2 can be derived in high precision from the ratio of the on-line center to off-line radiances; (c) together with CO2 gas absorption aerosol/cirrus cloud layer has differential scattering which may result in the modification of on-line to off-line radiance ratio which could lead a large bias in the total column CO2 retrieval. Approaches to correct such bias need further investigation. (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature, which is achievable from new atmospheric sounders in the near future; (e) the atmospheric path length, over which the CO2 absorption occurs, should be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

The effects of inhalation anaesthetics on common clinical pathology parameters in laboratory rats.

PubMed

Deckardt, K; Weber, I; Kaspers, U; Hellwig, J; Tennekes, H; van Ravenzwaay, B

2007-09-01

Effects of common anaesthetics such as ether, methoxyflurane, isoflurane, carbon dioxide (at 100%, 80% or 60% admixed with O(2)) on toxicity and clinical pathology parameters in rats were investigated. Ether, methoxyflurane and 100% CO(2) induced toxicity in some animals. Erythrocyte, haemoglobin and haematocrit were reduced in females by 100% CO(2), methoxyflurane and isoflurane. Glucose was increased by 60% CO(2), 80% CO(2), ether, isoflurane and methoxyflurane in males. Chloride was reduced by isoflurane and all CO(2) concentrations in females. Serum proteins were reduced by isoflurane and methoxyflurane. Sodium, inorganic phosphate, calcium and magnesium were reduced by methoxyflurane and isoflurane, but increased by all CO(2) concentrations. Potassium was reduced by ether, methoxyflurane or isoflurane. Triiodothyronine and thyroxine were reduced by all anaesthetics. Prolactin was reduced by methoxyflurane, but raised by ether and isoflurane. Erythrocyte cholinesterase (E-ChE) activity is markedly reduced (20-40%) after anaesthesia with all CO(2) concentrations in both sexes. E-ChE was unaffected by ether, methoxyflurane, or isoflurane. Serum and brain cholinesterase activities were not affected. E-ChE inhibition correlated with decreased blood pH, suggesting that this was caused by acidosis. This is of practical relevance in the risk assessment of cholinesterase inhibitors. Clinical pathology data were affected by all anaesthetics. CO(2)/O(2) (80%/20%) and isoflurane are the most suitable anaesthetics. If E-ChE activity is to be determined, isoflurane is the anaesthetic of choice.

A Review of Major Non-Power-Related Carbon Dioxide Stream Compositions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Last, George V.; Schmick, Mary T.

A critical component in the assessment of long-term risk from geologic sequestration of carbon dioxide (CO2) is the ability to predict mineralogical and geochemical changes within storage reservoirs as a result of rock-brine-CO2 reactions. Impurities and/or other constituents in CO2 source streams selected for sequestration can affect both the chemical and physical (e.g., density, viscosity, interfacial tension) properties of CO2 in the deep subsurface. The nature and concentrations of these impurities are a function of both the industrial source(s) of CO2, as well as the carbon capture technology used to extract the CO2 and produce a concentrated stream for subsurfacemore » injection and geologic sequestration. This article reviews the relative concentrations of CO2 and other constituents in exhaust gases from major non-energy-related industrial sources of CO2. Assuming that carbon capture technology would remove most of the incondensable gases N2, O2, and Ar, leaving SO2 and NOx as the main impurities, the authors then summarize the relative proportions of the remaining impurities assumed to be present in CO2 source streams that could be targeted for geologic sequestration. The summary is presented relative to five potential sources of CO2: 1) Flue Gas with Flue Gas Desulfurization, 2) Combustion Stack from Coke Production, 3) Portland Cement Kilns, 4) Natural Gas Combustion, and 5) Lime Production.« less

Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

NASA Astrophysics Data System (ADS)

Nakaten, Natalie; Islam, Rafiqul; Kempka, Thomas

2014-05-01

The application of underground coal gasification (UCG) with proven carbon mitigation techniques may provide a carbon neutral approach to tackle electricity and fertilizer supply shortages in Bangladesh. UCG facilitates the utilization of deep-seated coal seams, not economically exploitable by conventional coal mining. The high-calorific synthesis gas produced by UCG can be used for e.g. electricity generation or as chemical raw material for hydrogen, methanol and fertilizer production. Kempka et al. (2010) carried out an integrated assessment of UCG operation, demonstrating that about 19 % of the CO2 produced during UCG may be mitigated by CO2 utilization in fertilizer production. In the present study, we investigated an extension of the UCG system by introducing excess CO2 storage in the gas deposit of the Bahkrabad gas field (40 km east of Dhaka, Bangladesh). This gas field still holds natural gas resources of 12.8 million tons of LNG equivalent, but is close to abandonment due to a low reservoir pressure. Consequently, applying enhanced gas recovery (EGR) by injection of excess carbon dioxide from the coupled UCG-urea process may mitigate carbon emissions and support natural gas production from the Bahkrabad gas field. To carry out an integrated techno-economic assessment of the coupled system, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014) to consider the urea and EGR processes. Reservoir simulations addressing EGR in the Bakhrabad gas field by utilization of excess carbon dioxide from the UCG process were carried out to account for the induced pressure increase in the reservoir, and thus additional gas recovery potentials. The Jamalganj coal field in Northwest Bangladesh provides favorable geological and infrastructural conditions for a UCG operation at coal seam depths of 640 m to 1,158 m. Excess CO2 can be transported via existing pipeline networks to the Bahkrabad gas field (about 300 km distance from the coal deposit) to be injected in the scope of the scheduled EGR operation. Our techno-economic modeling results considering EGR reservoir simulations demonstrate that an economic and carbon neutral operation of UCG combined with fertilizer production and CCS is feasible. The suggested approach may provide a bridging technology to tackle fertilizer and power supply shortages in Bangladesh, and in addition support further production from depleting natural gas deposits. References Kempka, T., Plötz, M.L., Hamann, J., Deowan, S.A., Azzam, R. (2010) Carbon dioxide utilisation for carbamide production by application of the coupled UCG-urea process. Energy Procedia 4: 2200-2205. Nakaten, N., Schlüter, R., Azzam, R., Kempka, T. (2014) Development of a techno-economic model for dynamic calculation of COE, energy demand and CO2 emissions of an integrated UCG-CCS process. Energy (in print). Doi 10.1016/j.energy.2014.01.014

Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements

NASA Astrophysics Data System (ADS)

Paris, J.-D.; Stohl, A.; Nédélec, P.; Arshinov, M. Yu.; Panchenko, M. V.; Shmargunov, V. P.; Law, K. S.; Belan, B. D.; Ciais, P.

2009-09-01

We present airborne measurements of carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), equivalent black carbon (EBC) and ultra fine particles over North-Eastern Siberia in July 2008 performed during the YAK-AEROSIB/POLARCAT experiment. During a "golden day" (11 July 2008) a number of biomass burning plumes were encountered with CO concentration enhancements of up to 500 ppb relative to a background of 90 ppb. Number concentrations of aerosols in the size range 3.5-200 nm peaked at 4000 cm-3 and the EBC content reached 1.4 μg m-3. These high concentrations were caused by forest fires in the vicinity of the landing airport in Yakutsk where during the descent measurements in fresh smoke could be made. We estimate a combustion efficiency of 90±3% based on CO and CO2 measurements. The emission factor of CO emitted was 59.6±15.2 g CO per kilogram of dry matter burned, suggesting an increase in the average northern hemispheric CO concentration of 3.0-7.2 ppb per million hectares of Siberian forest burned. For BC, we estimate an emission factor of 0.52±0.07 g BC kg-1, comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5-200 nm) was 26 cm-3 (ppb CO)-1, consistent with other airborne studies. The transport of identified biomass burning plumes was investigated using the FLEXPART Lagrangian model. Based on sampling of wildfire plumes from the same source but with different atmospheric ages derived from FLEXPART, we estimate that the e-folding lifetimes of EBC and ultra fine particles (between 3.5 and 200 nm in size) against removal and growth processes are 5.1 and 5.5 days, respectively, supporting lifetimes estimates used in various modelling studies.

Expansion of mesenchymal stem cells under atmospheric carbon dioxide.

PubMed

Brodsky, Arthur Nathan; Zhang, Jing; Visconti, Richard P; Harcum, Sarah W

2013-01-01

Stem cells are needed for an increasing number of scientific applications, including both fundamental research and clinical disease treatment. To meet this rising demand, improved expansion methods to generate high quantities of high quality stem cells must be developed. Unfortunately, the bicarbonate buffering system - which relies upon an elevated CO2 environment - typically used to maintain pH in stem cell cultures introduces several unnecessary limitations in bioreactor systems. In addition to artificially high dissolved CO2 levels negatively affecting cell growth, but more importantly, the need to sparge CO2 into the system complicates the ability to control culture parameters. This control is especially important for stem cells, whose behavior and phenotype is highly sensitive to changes in culture conditions such as dissolved oxygen and pH. As a first step, this study developed a buffer to support expansion of mesenchymal stem cells (MSC) under an atmospheric CO2 environment in static cultures. MSC expanded under atmospheric CO2 with this buffer achieved equivalent growth rates without adaptation compared to those grown in standard conditions and also maintained a stem cell phenotype, self-renewal properties, and the ability to differentiate into multiple lineages after expansion. © 2013 American Institute of Chemical Engineers.

CO.sub.2 separation from low-temperature flue gases

DOEpatents

Dilmore, Robert; Allen, Douglas; Soong, Yee; Hedges, Sheila

2010-11-30

Two methods are provide for the separation of carbon dioxide from the flue gases. The first method utilizes a phase-separating moiety dissolved in an aqueous solution of a basic moiety to capture carbon dioxide. The second method utilizes a phase-separating moiety as a suspended solid in an aqueous solution of a basic moiety to capture carbon dioxide. The first method takes advantage of the surface-independent nature of the CO.sub.2 absorption reactions in a homogeneous aqueous system. The second method also provides permanent sequestration of the carbon dioxide. Both methods incorporate the kinetic rate enhancements of amine-based scrubbing while eliminating the need to heat the entire amine solution (80% water) in order to regenerate and release CO.sub.2. Both methods also take advantage of the low-regeneration temperatures of CO.sub.2-bearing mineral systems such as Na.sub.2CO.sub.3/NaHCO.sub.3 and K.sub.2CO.sub.3/KHCO.sub.3.

Sensitivity of the equilibrium surface temperature of a GCM to systematic changes in atmospheric carbon dioxide

NASA Technical Reports Server (NTRS)

Oglesby, Robert J.; Saltzman, Barry

1990-01-01

The equilibrium response of surface temperature to atmospheric CO2 concentration, for six values between 100 and 1000 ppm, is calculated from a series of GCM experiments. This response is nonlinear, showing greater sensitivity for lower values of CO2 than for the higher values. It is suggested that changes in CO2 concentration of a given magnitude (e.g., 100 ppm) played a larger role in the Pleistocene ice-age-type temperature variations than in causing global temperature changes due to anthropogenic increases.

Elevated Carbon Dioxide Concentration Reduces Alarm Signaling in Aphids.

PubMed

Boullis, Antoine; Fassotte, Bérénice; Sarles, Landry; Lognay, Georges; Heuskin, Stéphanie; Vanderplanck, Maryse; Bartram, Stefan; Haubruge, Eric; Francis, Frédéric; Verheggen, François J

2017-02-01

Insects often rely on olfaction to communicate with conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations might impact pheromonal communication in insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid, Acyrthosiphon pisum, under ambient and elevated CO 2 concentrations over several generations. We found that an increase in CO 2 concentration reduced the production (i.e., individual content) and emission (released under predation events) of Eβf. While no difference in Eβf neuronal perception was observed, we found that an increase in CO 2 strongly reduced the escape behavior expressed by an aphid colony following exposure to natural doses of alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases impact chemical communication in the pea aphid, and could potentially have a cascade effect on interactions with higher trophic levels.

Interactions between CO2 enhancement and N addition on net primary productivity and water-use efficiency in a mesocosm with multiple subtropical tree species.

PubMed

Yan, Junhua; Zhang, Deqiang; Liu, Juxiu; Zhou, Guoyi

2014-07-01

Carbon dioxide (CO2 ) enhancement (eCO2 ) and N addition (aN) have been shown to increase net primary production (NPP) and to affect water-use efficiency (WUE) for many temperate ecosystems, but few studies have been made on subtropical tree species. This study compared the responses of NPP and WUE from a mesocosm composing five subtropical tree species to eCO2 (700 ppm), aN (10 g N m(-2) yr(-1) ) and eCO2 × aN using open-top chambers. Our results showed that mean annual ecosystem NPP did not changed significantly under eCO2 , increased by 56% under aN and 64% under eCO2 × aN. Ecosystem WUE increased by 14%, 55%, and 61% under eCO2 , aN and eCO2 × aN, respectively. We found that the observed responses of ecosystem WUE were largely driven by the responses of ecosystem NPP. Statistical analysis showed that there was no significant interactions between eCO2 and aN on ecosystem NPP (P = 0.731) or WUE (P = 0.442). Our results showed that increasing N deposition was likely to have much stronger effects on ecosystem NPP and WUE than increasing CO2 concentration for the subtropical forests. However, different tree species responded quite differently. aN significantly increased annual NPP of the fast-growing species (Schima superba). Nitrogen-fixing species (Ormosia pinnata) grew significantly faster only under eCO2 × aN. eCO2 had no effects on annual NPP of those two species but significantly increased annual NPP of other two species (Castanopsis hystrix and Acmena acuminatissima). Differential responses of the NPP among different tree species to eCO2 and aN will likely have significant implications on the species composition of subtropical forests under future global change. © 2013 John Wiley & Sons Ltd.

Elevated carbon dioxide and warming impact silicon and phenolic-based defences differently in native and exotic grasses.

PubMed

Johnson, Scott N; Hartley, Susan E

2017-11-03

Global climate change may increase invasions of exotic plant species by directly promoting the success of invasive/exotic species or by reducing the competitive abilities of native species. Changes in plant chemistry, leading to altered susceptibility to stress, could mediate these effects. Grasses are hyper-accumulators of silicon, which play a crucial function in the alleviation of diverse biotic and abiotic stresses. It is unknown how predicted increases in atmospheric carbon dioxide (CO 2 ) and air temperature affect silicon accumulation in grasses, especially in relation to primary and secondary metabolites. We tested how elevated CO 2 (eCO 2 ) (+240 ppm) and temperature (eT) (+4°C) affected chemical composition (silicon, phenolics, carbon and nitrogen) and plant growth in eight grass species, either native or exotic to Australia. eCO 2 increased phenolic concentrations by 11%, but caused silicon accumulation to decline by 12%. Moreover, declines in silicon occurred mainly in native species (-19%), but remained largely unchanged in exotic species. Conversely, eT increased silicon accumulation in native species (+19%) but decreased silicon accumulation in exotic species (-10%). Silicon and phenolic concentrations were negatively correlated with each other, potentially reflecting a defensive trade-off. Moreover, both defences were negatively correlated with plant mass, compatible with a growth-defence trade-off. Grasses responded in a species-specific manner, suggesting that the relative susceptibility of different species may differ under future climates compared to current species rankings of resource quality. For example, the native Microlaena stipoides was less well defended under eCO 2 in terms of both phenolics and silicon, and thus could suffer greater vulnerability to herbivores. To our knowledge, this is the first demonstration of the impacts of eCO 2 and eT on silicon accumulation in grasses. We speculate that the greater plasticity in silicon uptake shown by Australian native grasses may be partly a consequence of evolving in a low nutrient and seasonally arid environment. © 2017 John Wiley & Sons Ltd.

Electrochemical Reduction of Carbon Dioxide to Methanol by Direct Injection of Electrons into Immobilized Enzymes on a Modified Electrode.

PubMed

Schlager, Stefanie; Dumitru, Liviu Mihai; Haberbauer, Marianne; Fuchsbauer, Anita; Neugebauer, Helmut; Hiemetsberger, Daniela; Wagner, Annika; Portenkirchner, Engelbert; Sariciftci, Niyazi Serdar

2016-03-21

We present results for direct bio-electrocatalytic reduction of CO2 to C1 products using electrodes with immobilized enzymes. Enzymatic reduction reactions are well known from biological systems where CO2 is selectively reduced to formate, formaldehyde, or methanol at room temperature and ambient pressure. In the past, the use of such enzymatic reductions for CO2 was limited due to the necessity of a sacrificial co-enzyme, such as nicotinamide adenine dinucleotide (NADH), to supply electrons and the hydrogen equivalent. The method reported here in this paper operates without the co-enzyme NADH by directly injecting electrons from electrodes into immobilized enzymes. We demonstrate the immobilization of formate, formaldehyde, and alcohol dehydrogenases on one-and-the-same electrode for direct CO2 reduction. Carbon felt is used as working electrode material. An alginate-silicate hybrid gel matrix is used for the immobilization of the enzymes on the electrode. Generation of methanol is observed for the six-electron reduction with Faradaic efficiencies of around 10%. This method of immobilization of enzymes on electrodes offers the opportunity for electrochemical application of enzymatic electrodes to many reactions in which a substitution of the expensive sacrificial co-enzyme NADH is desired. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Promising flame retardant textile in supercritical carbon dioxide

USDA-ARS?s Scientific Manuscript database

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...

Revisiting the social cost of carbon.

PubMed

Nordhaus, William D

2017-02-14

The social cost of carbon (SCC) is a central concept for understanding and implementing climate change policies. This term represents the economic cost caused by an additional ton of carbon dioxide emissions or its equivalent. The present study presents updated estimates based on a revised DICE model (Dynamic Integrated model of Climate and the Economy). The study estimates that the SCC is $31 per ton of CO 2 in 2010 US$ for the current period (2015). For the central case, the real SCC grows at 3% per year over the period to 2050. The paper also compares the estimates with those from other sources.

Revisiting the social cost of carbon

NASA Astrophysics Data System (ADS)

Nordhaus, William D.

2017-02-01

The social cost of carbon (SCC) is a central concept for understanding and implementing climate change policies. This term represents the economic cost caused by an additional ton of carbon dioxide emissions or its equivalent. The present study presents updated estimates based on a revised DICE model (Dynamic Integrated model of Climate and the Economy). The study estimates that the SCC is 31 per ton of CO2 in 2010 US for the current period (2015). For the central case, the real SCC grows at 3% per year over the period to 2050. The paper also compares the estimates with those from other sources.

Computer simulation of energy use, greenhouse gas emissions, and process economics of the fluid milk process.

PubMed

Tomasula, P M; Yee, W C F; McAloon, A J; Nutter, D W; Bonnaillie, L M

2013-05-01

Energy-savings measures have been implemented in fluid milk plants to lower energy costs and the energy-related carbon dioxide (CO2) emissions. Although these measures have resulted in reductions in steam, electricity, compressed air, and refrigeration use of up to 30%, a benchmarking framework is necessary to examine the implementation of process-specific measures that would lower energy use, costs, and CO2 emissions even further. In this study, using information provided by the dairy industry and equipment vendors, a customizable model of the fluid milk process was developed for use in process design software to benchmark the electrical and fuel energy consumption and CO2 emissions of current processes. It may also be used to test the feasibility of new processing concepts to lower energy and CO2 emissions with calculation of new capital and operating costs. The accuracy of the model in predicting total energy usage of the entire fluid milk process and the pasteurization step was validated using available literature and industry energy data. Computer simulation of small (40.0 million L/yr), medium (113.6 million L/yr), and large (227.1 million L/yr) processing plants predicted the carbon footprint of milk, defined as grams of CO2 equivalents (CO2e) per kilogram of packaged milk, to within 5% of the value of 96 g of CO 2e/kg of packaged milk obtained in an industry-conducted life cycle assessment and also showed, in agreement with the same study, that plant size had no effect on the carbon footprint of milk but that larger plants were more cost effective in producing milk. Analysis of the pasteurization step showed that increasing the percentage regeneration of the pasteurizer from 90 to 96% would lower its thermal energy use by almost 60% and that implementation of partial homogenization would lower electrical energy use and CO2e emissions of homogenization by 82 and 5.4%, respectively. It was also demonstrated that implementation of steps to lower non-process-related electrical energy in the plant would be more effective in lowering energy use and CO2e emissions than fuel-related energy reductions. The model also predicts process-related water usage, but this portion of the model was not validated due to a lack of data. The simulator model can serve as a benchmarking framework for current plant operations and a tool to test cost-effective process upgrades or evaluate new technologies that improve the energy efficiency and lower the carbon footprint of milk processing plants. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Spin Uncoupling in Chemisorbed OCCO and CO 2: Two High-Energy Intermediates in Catalytic CO 2 Reduction

DOE PAGES

Hedstrom, Svante; dos Santos, Egon Campos; Liu, Chang; ...

2018-05-08

Here, the production of useful compounds via the electrochemical carbon dioxide reduction reaction (CO2RR) is a matter of intense research. Although the thermodynamics and kinetic barriers of CO2RR are reported in previous computational studies, the electronic structure details are often overlooked. We study two important CO2RR intermediates: ethylenedione (OCCO) and CO 2 covalently bound to cluster and slab models of the Cu(100) surface. Both molecules exhibit a near-unity negative charge as chemisorbed, but otherwise they behave quite differently, as explained by a spin-uncoupling perspective. OCCO adopts a high-spin, quartetlike geometry, allowing two covalent bonds to the surface with an averagemore » gross interaction energy of –1.82 eV/bond. The energy cost for electronically exciting OCCO– to the quartet state is 1.5 eV which is readily repaid via the formation of its two surface bonds. CO 2, conversely, retains a low-spin, doubletlike structure upon chemisorption, and its single unpaired electron forms a single covalent surface bond of –2.07 eV. The 5.0 eV excitation energy to the CO 2 – quartet state is prohibitively costly and cannot be compensated for by an additional surface bond.« less

Change in end-tidal carbon dioxide outperforms other surrogates for change in cardiac output during fluid challenge.

PubMed

Lakhal, K; Nay, M A; Kamel, T; Lortat-Jacob, B; Ehrmann, S; Rozec, B; Boulain, T

2017-03-01

During fluid challenge, volume expansion (VE)-induced increase in cardiac output (Δ VE CO) is seldom measured. In patients with shock undergoing strictly controlled mechanical ventilation and receiving VE, we assessed minimally invasive surrogates for Δ VE CO (by transthoracic echocardiography): fluid-induced increases in end-tidal carbon dioxide (Δ VE E'CO2 ); pulse (Δ VE PP), systolic (Δ VE SBP), and mean systemic blood pressure (Δ VE MBP); and femoral artery Doppler flow (Δ VE FemFlow). In the absence of arrhythmia, fluid-induced decrease in heart rate (Δ VE HR) and in pulse pressure respiratory variation (Δ VE PPV) were also evaluated. Areas under the receiver operating characteristic curves (AUC ROC s) reflect the ability to identify a response to VE (Δ VE CO ≥15%). In 86 patients, Δ VE E'CO2 had an AUC ROC =0.82 [interquartile range 0.73-0.90], significantly higher than the AUC ROC for Δ VE PP, Δ VE SBP, Δ VE MBP, and Δ VE FemFlow (AUC ROC =0.61-0.65, all P  <0.05). A value of Δ VE E'CO2  >1 mm Hg (>0.13 kPa) had good positive (5.0 [2.6-9.8]) and fair negative (0.29 [0.2-0.5]) likelihood ratios. The 16 patients with arrhythmia had similar relationships between Δ VE E'CO2 and Δ VE CO to patients with regular rhythm ( r 2 =0.23 in both subgroups). In 60 patients with no arrhythmia, Δ VE E'CO2 (AUC ROC =0.84 [0.72-0.92]) outperformed Δ VE HR (AUC ROC =0.52 [0.39-0.66], P <0.05) and tended to outperform Δ VE PPV (AUC ROC =0.73 [0.60-0.84], P =0.21). In the 45 patients with no arrhythmia and receiving ventilation with tidal volume <8 ml kg -1 , Δ VE E'CO2 performed better than Δ VE PPV, with AUC ROC =0.86 [0.72-0.95] vs 0.66 [0.49-0.80], P =0.02. Δ VE E'CO2 outperformed Δ VE PP, Δ VE SBP, Δ VE MBP, Δ VE FemFlow, and Δ VE HR and, during protective ventilation, arrhythmia, or both, it also outperformed Δ VE PPV. A value of Δ VE E'CO2 >1 mm Hg (>0.13 kPa) indicated a likely response to VE. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Briefing on geological sequestration (Tulsa)

EPA Science Inventory

Geological sequestration (GS) is generally recognized as the injection and long-term (e.g., hundreds to thousands of years) trapping of gaseous, liquid or supercritical carbon dioxide (CO2) in subsurface media – primarily saline formations, depleted or nearly depleted oil and gas...

Disintegration of Carbon Dioxide Molecules in a Microwave Plasma Torch.

PubMed

Kwak, Hyoung S; Uhm, Han S; Hong, Yong C; Choi, Eun H

2015-12-17

A pure carbon dioxide torch is generated by making use of 2.45 GHz microwave. Carbon dioxide gas becomes the working gas and produces a stable carbon dioxide torch. The torch volume is almost linearly proportional to the microwave power. Temperature of the torch flame is measured by making use of optical spectroscopy and thermocouple. Two distinctive regions are exhibited, a bright, whitish region of high-temperature zone and a bluish, dimmer region of relatively low-temperature zone. Study of carbon dioxide disintegration and gas temperature effects on the molecular fraction characteristics in the carbon dioxide plasma of a microwave plasma torch under atmospheric pressure is carried out. An analytical investigation of carbon dioxide disintegration indicates that substantial fraction of carbon dioxide molecules disintegrate and form other compounds in the torch. For example, the normalized particle densities at center of plasma are given by nCO2/nN = 6.12 × 10(-3), nCO/nN = 0.13, nC/nN = 0.24, nO/nN = 0.61, nC2/nN = 8.32 × 10(-7), nO2/nN = 5.39 × 10(-5), where nCO2, nCO, nC, nO, nC2, and nO2 are carbon dioxide, carbon monoxide, carbon and oxygen atom, carbon and oxygen molecule densities, respectively. nN is the neutral particle density. Emission profiles of the oxygen and carbon atom radicals and the carbon monoxide molecules confirm the theoretical predictions of carbon dioxide disintegration in the torch.

Comparison of CO2 Photoreduction Systems: A Review

EPA Science Inventory

Carbon dioxide (CO2) emissions are a major contributor to the climate change equation. To alleviate concerns of global warming, strategies to mitigate increase of CO2 levels in the atmosphere have to be developed. The most desirable approach is to convert the carbon dioxide to us...

Rare isotope studies involving catalytic oxidation of CO over platinum-tin oxide

NASA Technical Reports Server (NTRS)

Upchurch, Billy T.; Wood, George M., Jr.; Hess, Robert V.; Hoyt, Ronald F.

1987-01-01

Results of studies utilizing normal and rare oxygen isotopes in the catalytic oxidation of carbon monoxide over a platinum-tin oxide catalyst substrate are presented. Chemisorption of labeled carbon monoxide on the catalyst followed by thermal desorption yielded a carbon dioxide product with an oxygen-18 composition consistent with the formation of a carbonate-like intermediate in the chemisorption process. The efficacy of a method developed for the oxygen-18 labeling of the platinum-tin oxide catalyst surface for use in closed cycle pulsed care isotope carbon dioxide lasers is demonstrated for the equivalent of 10 to the 6th power pulses at 10 pulses per second.

Natural sources of greenhouse gases: carbon dioxide emissions from volcanoes

USGS Publications Warehouse

Gerlach, Terrence

1990-01-01

Volcanic degassing of carbon dioxide plays an important role in keeping the atmosphere-ocean portion of the carbon geochemical cycle in balance. The atmosphere-ocean carbon deficit requires replenishment of 6??1012 mol CO2/yr, and places an upper limit on the output of carbon dioxide from volcanoes. The CO2 output of the global mid-oceanic ridge system is ca. 0.7??1012 mol/yr, thus supplying only a fraction of the amount needed to balance the carbon deficit. The carbon dioxide flux from subaerial volcanoes is poorly known, but it appears to be at least as large as the mid-oceanic ridge flux. Much (perhaps most) of the CO2 emitted from volcanoes is degassed noneruptively. This mode of degassing may lead to impacts on the environment and biosphere that are fundamentally different in character from those envisioned in published scenarios, which are based on the assumption that CO2 degassing occurs predominantly by eruptive processes. Although the flux of carbon dioxide from volcanoes is poorly constrained at present, it is clearly two orders of magnitude lower than the anthropogenic output of CO2.

Optimizing fluence and debridement effects on cutaneous resurfacing carbon dioxide laser surgery.

PubMed

Weisberg, N K; Kuo, T; Torkian, B; Reinisch, L; Ellis, D L

1998-10-01

To develop methods to compare carbon dioxide (CO2) resurfacing lasers, fluence, and debridement effects on tissue shrinkage and histological thermal denaturation. In vitro human or in vivo porcine skin samples received up to 5 passes with scanner or short-pulsed CO2 resurfacing lasers. Fluences ranging from 2.19 to 17.58 J/cm2 (scanner) and 1.11 to 5.56 J/cm2 (short pulsed) were used to determine each laser's threshold energy for clinical effect. Variable amounts of debridement were also studied. Tissue shrinkage was evaluated by using digital photography to measure linear distance change of the treated tissue. Tissue histological studies were evaluated using quantitative computer image analysis. Fluence-independent in vitro tissue shrinkage was seen with the scanned and short-pulsed lasers above threshold fluence levels of 5.9 and 2.5 J/cm2, respectively. Histologically, fluence-independent thermal depths of damage of 77 microns (scanner) and 25 microns (pulsed) were observed. Aggressive debridement of the tissue increased the shrinkage per pass of the laser, and decreased the fluence required for the threshold effect. In vivo experiments confirmed the in vitro results, although the in vivo threshold fluence level was slightly higher and the shrinkage obtained was slightly lower per pass. Our methods allow comparison of different resurfacing lasers' acute effects. We found equivalent laser tissue effects using lower fluences than those currently accepted clinically. This suggests that the morbidity associated with CO2 laser resurfacing may be minimized by lowering levels of tissue input energy and controlling for tissue debridement.

Quenching of highly vibrationally excited pyrimidine by collisions with CO2

NASA Astrophysics Data System (ADS)

Johnson, Jeremy A.; Duffin, Andrew M.; Hom, Brian J.; Jackson, Karl E.; Sevy, Eric T.

2008-02-01

Relaxation of highly vibrationally excited pyrimidine (C4N2H4) by collisions with carbon dioxide has been investigated using diode laser transient absorption spectroscopy. Vibrationally hot pyrimidine (E'=40635cm-1) was prepared by 248-nm excimer laser excitation, followed by rapid radiationless relaxation to the ground electronic state. The nascent rotational population distribution (J=58-80) of the 0000 ground state of CO2 resulting from collisions with hot pyrimidine was probed at short times following the excimer laser pulse. Doppler spectroscopy was used to measure the CO2 recoil velocity distribution for J =58-80 of the 0000 state. Rate constants and probabilities for collisions populating these CO2 rotational states were determined. The measured energy transfer probabilities, indexed by final bath state, were resorted as a function of ΔE to create the energy transfer distribution function, P(E,E'), from E'-E˜1300-7000cm-1. P(E,E') is fitted to a single exponential and a biexponential function to determine the average energy transferred in a single collision between pyrimidine and CO2 and parameters that can be compared to previously studied systems using this technique, pyrazine/CO2, C6F6/CO2, and methylpyrazine/CO2. P(E,E') parameters for these four systems are also compared to various molecular properties of the donor molecules. Finally, P(E,E') is analyzed in the context of two models, one which suggests that the shape of P(E,E') is primarily determined by the low-frequency out-of-plane donor vibrational modes and one which suggests that the shape of P(E,E') can be determined by how the donor molecule final density of states changes with ΔE.

Nickel-Coated Aluminum Particles: A Promising Fuel for Mars Missions

NASA Technical Reports Server (NTRS)

Shafirovich, Evgeny; Varma, Arvind

2004-01-01

Combustion of metals in carbon dioxide is a promising source of energy for propulsion on Mars. This approach is based on the ability of some metals (e.g. Mg, Al) to burn in CO2 atmosphere and suggests use of the Martian carbon dioxide as an oxidizer in jet or rocket engines. Analysis shows that CO2/metal propulsion will reduce significantly the mass of propellant transported from Earth for long-range mobility on Mars and sample return missions. Recent calculations for the near-term missions indicate that a 200-kg ballistic hopper with CO2/metal rocket engines and a CO2 acquisition unit can perform 10-15 flights on Mars with the total range of 10-15 km, i.e. fulfill the exploration program typically assigned for a rover. Magnesium is currently recognized as a candidate fuel for such engines owing to easy ignition and fast burning in CO2. Aluminum may be more advantageous if a method for reducing its ignition temperature is found. Coating it by nickel is one such method. It is known that a thin nickel layer of nickel on the surface of aluminum particles can prevent their agglomeration and simultaneously facilitate their ignition, thus increasing the efficiency of aluminized propellants. Combustion of single Ni-coated Al particles in different gas environments (O2, CO2, air) was studied using electrodynamic levitation and laser ignition. It was shown that the combustion mechanisms depend on the ambient atmosphere. Combustion in CO2 is characterized by the smaller size and lower brightness of flame than in O2, and by phenomena such as micro-flashes and fragment ejection. The size and brightness of flame gradually decrease as the particle burns.

Supercritical carbon dioxide fractionation of whey protein isolate for new food-grade ingredients

USDA-ARS?s Scientific Manuscript database

A new, environmentally benign whey protein fractionation process was developed using supercritical CO2 (SCO2) as an acid aggregating agent to separate a-lactalbumin (a-LA) aggregates from soluble beta-lactoglobulin (beta-LG) protein in concentrated whey protein isolate (WPI) solutions. The process e...

Heteroatom-doped nanoporous carbon derived from MOF-5 for CO2 capture

NASA Astrophysics Data System (ADS)

Ma, Xiancheng; Li, Liqing; Chen, Ruofei; Wang, Chunhao; Li, Hailong; Wang, Shaobin

2018-03-01

Four nanoporous carbons (MUCT) were prepared from metal-organic framework (MOF-5) template and additional carbon source (i.e. urea) by carbonization at different temperatures (600-900 °C). The results showed that specific surface area of four samples was obtained in the range from 1030 to 2307 m2 g-1. By changing the carbonization temperature it can finely tune the pore volume of the MUCT, which having a uniform pore size of around 4.0 nm. With an increasing carbonization temperature, the micropore surface area of MUCT samples varied slightly, but mesopore surface area increased obviously, which had little influence on carbon dioxide (CO2) adsorption capacity. The as-obtained sample MUC900 exhibited the superior CO2 capture capacity of 3.7 mmol g-1 at 0 °C (1 atm). First principle calculations were conducted on carbon models with various functional groups to distinguish heterogeneity and understand carbon surface chemistry for CO2 adsorption. The interaction between CO2 and N-containing functional groups is mainly weak Lewis acid-base interaction. On the other hand, the pyrrole and amine groups show exceptional hydrogen-bonding interaction. The hydroxyls promote the interaction between carbon dioxide and functional groups through hydrogen-bonding interactions and electrostatic potentials, thereby increasing CO2 capture of MUCT.

Anaesthesia for laparoscopic nephrectomy: Does end-tidal carbon dioxide measurement correlate with arterial carbon dioxide measurement?

PubMed

Jayan, Nithin; Jacob, Jaya Susan; Mathew, Mohan

2018-04-01

Not many studies have explored the correlation between arterial carbon dioxide tension (PaCO 2 ) and end-tidal carbon dioxide tension (ETCO 2 ) in surgeries requiring pneumoperitoneum of more than 1 hour duration with the patient in non-supine position. The aim of our study was to evaluate the correlation of ETCO 2 with PaCO 2 in patients undergoing laparoscopic nephrectomy under general anaesthesia. A descriptive study was performed in thirty patients undergoing laparoscopic nephrectomy from September 2014 to August 2015. The haemodynamic parameters, minute ventilation, PaCO 2 and ETCO 2 measured at three predetermined points during the procedure were analysed. Correlation was checked using Pearson's Correlation Coefficient Test. P <0.05 was considered statistically significant. Statistical analysis of the values showed a positive correlation between ETCO 2 and PaCO 2 ( P < 0.05). Following carbon dioxide insufflation, both ETCO 2 and PaCO 2 increased by 5.4 and 6.63 mmHg, respectively, at the end of the 1 st hour. The PaCO 2 -ETCO 2 gradient was found to increase during the 1 st hour following insufflation (4.07 ± 2.05 mmHg); it returned to the pre-insufflation values in another hour (2.93 ± 1.43 mmHg). Continuous ETCO 2 monitoring is a reliable indicator of the trend in arterial CO 2 fluctuations in the American Society of Anesthesiologists Grades 1 and 2 patients undergoing laparoscopic nephrectomy under general anaesthesia.

Effect of chemical sanitizer combined with modified atmosphere packaging on inhibiting Escherichia coli O157:H7 in commercial spinach.

PubMed

Lee, Sun-Young; Baek, Seung-Youb

2008-06-01

Escherichia coli O157:H7 contaminated spinach has recently caused several outbreaks of human illness in the USA and Canada. However, to date, there has been no study demonstrating an effective way to eliminate E. coli O157:H7 in spinach. Therefore, this study was conducted to investigate the effect of chemical sanitizers alone or in combination with packaging methods such as vacuum and modified atmosphere packaging (MAP) on inactivating E. coli O157:H7 in spinach during storage time. Spinach inoculated with E. coli O157:H7 was packaged in four different methods (air, vacuum, N(2) gas, and CO(2) gas packaging) following treatment with water, 100 ppm chlorine dioxide, or 100 ppm sodium hypochlorite for 5 min at room temperature and stored at 7+/-2 degrees C. Treatment with water did not significantly reduce levels of E. coli O157:H7 in spinach. However, treatment with chlorine dioxide and sodium hypochlorite significantly decreased levels of E. coli O157:H7 by 2.6 and 1.1 log(10)CFU/g, respectively. Levels of E. coli O157:H7 in samples packaged in air following treatments grew during storage time, whereas levels were maintained in samples packaged in other packaging methods (vacuum, N(2) gas, and CO(2) gas packaging). Therefore there were significant differences (about 3-4 log) of E. coli O157:H7 populations between samples packed in air and other packaging methods following treatment with chemical sanitizers after 7 days storage. These results suggest that the combination of treatment with chlorine dioxide and packaging methods such as vacuum and MAP may be useful for improving the microbial safety of spinach against E. coli O157:H7 during storage.

A life cycle assessment of options for producing synthetic fuel via pyrolysis.

PubMed

Vienescu, D N; Wang, J; Le Gresley, A; Nixon, J D

2018-02-01

The aim of this study was to investigate the sustainability of producing synthetic fuels from biomass using thermochemical processing and different upgrading pathways. Life cycle assessment (LCA) models consisting of biomass collection, transportation, pre-treatment, pyrolysis and upgrading stages were developed. To reveal the environmental impacts associated with greater post-processing to achieve higher quality fuels, six different bio-oil upgrading scenarios were analysed and included esterification, ketonisation, hydrotreating and hydrocracking. Furthermore, to take into account the possible ranges in LCA inventory data, expected, optimistic and pessimistic values for producing and upgrading pyrolysis oils were evaluated. We found that the expected carbon dioxide equivalent emissions could be as high as 6000 gCO 2e /kg of upgraded fuel, which is greater than the emissions arising from the use of diesel fuel. Other environmental impacts occurring from the fuel production process are outlined, such as resource depletion, acidification and eutrophication. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elevated CO2 impacts bell pepper growth with consequences to Myzus persicae life history, feeding behaviour and virus transmission ability.

PubMed

Dáder, Beatriz; Fereres, Alberto; Moreno, Aránzazu; Trębicki, Piotr

2016-01-08

Increasing atmospheric carbon dioxide (CO2) impacts plant growth and metabolism. Indirectly, the performance and feeding of insects is affected by plant nutritional quality and resistance traits. Life history and feeding behaviour of Myzus persicae were studied on pepper plants under ambient (aCO2, 400 ppm) or elevated CO2 (eCO2, 650 ppm), as well as the direct impact on plant growth and leaf chemistry. Plant parameters were significantly altered by eCO2 with a negative impact on aphid's life history. Their pre-reproductive period was 11% longer and fecundity decreased by 37%. Peppers fixed significantly less nitrogen, which explains the poor aphid performance. Plants were taller and had higher biomass and canopy temperature. There was decreased aphid salivation into sieve elements, but no differences in phloem ingestion, indicating that the diminished fitness could be due to poorer tissue quality and unfavourable C:N balance, and that eCO2 was not a factor impeding feeding. Aphid ability to transmit Cucumber mosaic virus (CMV) was studied by exposing source and receptor plants to ambient (427 ppm) or elevated (612 ppm) CO2 before or after virus inoculation. A two-fold decrease on transmission was observed when receptor plants were exposed to eCO2 before aphid inoculation when compared to aCO2.

Elevated CO2 impacts bell pepper growth with consequences to Myzus persicae life history, feeding behaviour and virus transmission ability

NASA Astrophysics Data System (ADS)

Dáder, Beatriz; Fereres, Alberto; Moreno, Aránzazu; Trębicki, Piotr

2016-01-01

Increasing atmospheric carbon dioxide (CO2) impacts plant growth and metabolism. Indirectly, the performance and feeding of insects is affected by plant nutritional quality and resistance traits. Life history and feeding behaviour of Myzus persicae were studied on pepper plants under ambient (aCO2, 400 ppm) or elevated CO2 (eCO2, 650 ppm), as well as the direct impact on plant growth and leaf chemistry. Plant parameters were significantly altered by eCO2 with a negative impact on aphid’s life history. Their pre-reproductive period was 11% longer and fecundity decreased by 37%. Peppers fixed significantly less nitrogen, which explains the poor aphid performance. Plants were taller and had higher biomass and canopy temperature. There was decreased aphid salivation into sieve elements, but no differences in phloem ingestion, indicating that the diminished fitness could be due to poorer tissue quality and unfavourable C:N balance, and that eCO2 was not a factor impeding feeding. Aphid ability to transmit Cucumber mosaic virus (CMV) was studied by exposing source and receptor plants to ambient (427 ppm) or elevated (612 ppm) CO2 before or after virus inoculation. A two-fold decrease on transmission was observed when receptor plants were exposed to eCO2 before aphid inoculation when compared to aCO2.

Energy use and climate change improvements of Li/S batteries based on life cycle assessment

NASA Astrophysics Data System (ADS)

Arvidsson, Rickard; Janssen, Matty; Svanström, Magdalena; Johansson, Patrik; Sandén, Björn A.

2018-04-01

We present a life cycle assessment (LCA) study of a lithium/sulfur (Li/S) cell regarding its energy use (in electricity equivalents, kWhel) and climate change (in kg carbon dioxide equivalents, CO2 eq) with the aim of identifying improvement potentials. Possible improvements are illustrated by departing from a base case of Li/S battery design, electricity from coal power, and heat from natural gas. In the base case, energy use is calculated at 580 kWhel kWh-1 and climate change impact at 230 kg CO2 eq kWh-1 of storage capacity. The main contribution to energy use comes from the LiTFSI electrolyte salt production and the main contribution to climate change is electricity use during the cell production stage. By (i) reducing cell production electricity requirement, (ii) sourcing electricity and heat from renewable sources, (iii) improving the specific energy of the Li/S cell, and (iv) switching to carbon black for the cathode, energy use and climate change impact can be reduced by 54 and 93%, respectively. For climate change, our best-case result of 17 kg CO2 eq kWh-1 is of similar magnitude as the best-case literature results for lithium-ion batteries (LIBs). The lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude.

Carbon Dioxide Emissions Due to Forest Fires in Bukit Batu Area, Bengkalis Regency, Indonesia

NASA Astrophysics Data System (ADS)

Anita, Sofia; Ariful Amri, T.; Abu Hanifah, T.; Furnando, Edo; Lukas, Amos

2017-05-01

High concentration of carbon dioxide in the atmosphere is the major cause of global warming. This study focuses on estimation of carbon emissions from forest fires in Indonesia, especially Bukit Batu area, Bengkalis Regency. Peatlands in this area are widely used as an agricultural cultivation and plantations. The aim of this study is to measure the concentration of CO2 emitted based on the relationship of physical and chemical properties of peat soil. Measurements carried out on these peatlands with different vegetation covered, i.e. bush land, palm plantations and secondary forests. Methods used in this research were Infrared Gas Analyzer and Gas Chromatography. The average of CO2 emissions obtained of bush land, palm plantations, and secondary forest were 497.4 ppm; 523. 2 ppm; and 457.2 ppm, respectively.

Joint DoD/DoE Shale Oil Project. Volume 3. Testing of Refined Shale Oil Fuels.

DTIC Science & Technology

1983-12-01

inches displacement NO Nitric oxide CLR Cooperative Lubrication Research NOX Oxides of nitrogen CO Carbon monoxide CO2 Carbon dioxide cSt Centistokes... composition and properties, and evaluation of toxicity. This report summarizes the results of these test and evalua- tion studies. The Paraho/Sohio effort...TABLE 11-1. DOE ALTERNATIVE FUELS PROGRAM DIESEL ENGINE TESTS WITH SHALE FUELS ............................... 11-11 TABLE 11-2. COMPOSITION OF

Feasibility of Applying Clean Development Mechanism and GHGs Emission Reductions in the Gold Mining Industry: A Case of Thailand

NASA Astrophysics Data System (ADS)

Kittipongvises, Suthirat

2015-12-01

There is presently overwhelming scientific consensus that global climate change is indeed occurring, and that human activities are the primary driver. An increasingly resource and carbon constrained world will continue to pose formidable challenges to major industries, including mining. Understanding the implications of climate change mitigation for the mining industry, however, remains limited. This paper presents the results of a feasibility study on the implementation of a clean development mechanism and greenhouse gases (GHGs) emission reductions in the gold mining industry. It draws upon and extends the analysis of a case study conducted on gold mining operations in Thailand. The results from the case study indicated that total GHGs emissions by company A were approximately 36,886 tons carbon dioxide equivalents (tCO2e) per annual gold production capacity that meet the eligibility criteria for small-scaled clean development mechanism (CDM) projects. The electrostatic separation process was found to release the lowest amount of GHGs, whereas comminution (i.e. crushing and grinding) generated the highest GHGs emissions. By scope, the emission from purchased electricity (scope 2) is the most significant source. Opportunities for CDM projects implementation in the gold mining sector can be found in employing energy efficiency measures. Through innovation, some technical efficiency and technological development in gold processing (i.e. high pressure grinding rolls (HPGR), vertical roller mills (VRM), gravity pre-concentration and microwave heating technologies) that have the potential to reduce energy use and also lower carbon footprint of the gold mining were further discussed. The evidence reviews found that HPGR and VRM abatement technologies have shown energy and climate benefits as electricity savings and CO2 reduction of about 8-25.93 kWh/ton ore processed and 1.8-26.66 kgCO2/ton ore processed, respectively. Implications for further research and practice were finally raised.

Polymers prepared from plant oils in liquid carbon dioxide

USDA-ARS?s Scientific Manuscript database

Recently, attention has been focused on the preparation of polymers in environmentally friendly media. Supercritical carbon dioxide (scCO2) is a promising candidate. The low toxicity of CO2 and lack of toxic solvent residues in the final products make CO2 an attractive medium for the synthesis of ...

40 CFR Table A-1 to Subpart A of... - Summary of Applicable Requirements for Reference and Equivalent Methods for Air Monitoring of...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Methods for Air Monitoring of Criteria Pollutants Pollutant Ref. or equivalent Manual or automated Applicable part 50 appendix Applicable subparts of part 53 A B C D E F SO2 Reference Manual A Equivalent Manual ✓ ✓ Automated ✓ ✓ ✓ CO Reference Automated C ✓ ✓ Equivalent Manual ✓ ✓ Automated ✓ ✓ ✓ O3...

Molecular properties of metal difluorides and their interactions with CO2 and H2O molecules: a DFT investigation.

PubMed

Arokiyanathan, Agnes Lincy; Lakshmipathi, Senthilkumar

2017-11-18

A computational study of metal difluorides (MF 2 ; M = Ca to Zn) and their interactions with carbon dioxide and water molecules was performed. The structural parameter values obtained and the results of AIM analysis and energy decomposition analysis indicated that the Ca-F bond is weaker and less ionic than the bonds in the transition metal difluorides. A deformation density plot revealed the stablizing influence of the Jahn-Teller effect in nonlinear MF 2 molecules (e.g., where M= Sc, Ti, Cr). An anaysis of the metal K-edge peaks of the difluorides showed that shifts in the edge energy were due to the combined effects of the ionicity, effective nuclear charge, and the spin state of the metal. The interactions of CO 2 with ScF 2 (Scc3 geometry) and TiF 2 (Tic2 geometry) caused CO 2 to shift from its usual linear geometry to a bent geometry (η 2 (C=O) binding mode), while it retained its linear geometry (η 1 (O) binding mode) when it interacted with the other metal difluorides. Energy decomposition analysis showed that, among the various geometries considered, the Scc3 and Tic2 geometries possessed the highest interaction energies and orbital interaction energies. Heavier transition metal difluorides showed stronger affinities for H 2 O, whereas the lighter transition metal (Sc and Ti) difluorides preferred CO 2 . Overall, the results of this study suggest that fluorides of lighter transition metals with partially filled d orbitals (e.g., Sc and Ti) could be used for CO 2 capture under moist conditions. Graphical abstract Interaction of metal difluorides with carbon dioxide and water.

Noninvasive measurement of mean alveolar carbon dioxide tension and Bohr's dead space during tidal breathing.

PubMed

Koulouris, N G; Latsi, P; Dimitroulis, J; Jordanoglou, B; Gaga, M; Jordanoglou, J

2001-06-01

The lack of methodology for measuring the alveolar carbon dioxide tension (PA,CO2) has forced investigators to make several assumptions, such as that PA,CO2 is equal to end-tidal (PET,CO2) and arterial CO2 tension (Pa,CO2). The present study measured the mean PA,CO2 and Bohr's dead space ratio (Bohr's dead space/tidal volume (VD,Bohr/VT)) during tidal breathing. The method used is a new, simple and noninvasive technique, based on the analysis of the expired CO2 volume per breath (VCO2) versus the exhaled VT. This curve was analysed in 21 normal, healthy subjects and 35 chronic obstructive pulmonary disease (COPD) patients breathing tidally through a mouthpiece apparatus in the sitting position. It is shown that: 1) PA,CO2 is similar to Pa,CO2 in normal subjects, whilst it is significantly lower than Pa,CO2 in COPD patients; 2) PA,CO2 is significantly higher than PET,CO2 in all subjects, especially in COPD patients; 3) VD,Bohr/VT is increased in COPD patients as compared to normal subjects; and 4) VD,Bohr/VT is lower than the "physiological" dead space ratio (VD,phys/VT) in COPD patients. It is concluded that the expired carbon dioxide versus tidal volume curve is a useful tool for research and clinical work, because it permits the noninvasive and accurate measurement of Bohr's dead space and mean alveolar carbon dioxide tension accurately during spontaneous breathing.

Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowley, R.L.; Adams, M.E.; Marshall, T.L.

1997-03-01

Natural gas processors use amine treating processes to remove the acid gases H{sub 2}S and CO{sub 2} from gas streams. Absorption rates of gaseous CO{sub 2} into aqueous N-methyldiethanolamine (MDEA) solutions were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. The absorption rate was found to be insensitive to the diffusion coefficient of CO{sub 2} in solution but very sensitive to the diffusion rate of bicarbonate and protonated MDEA ions. Evidence also suggested that chemical reaction equilibrium is rapid relative to diffusion. A numerical model was developed on the basis of these observations. The modelmore » was used to regress diffusion coefficients of bicarbonate and protonated amine, which must be equivalent by electroneutrality arguments, from measured absorption rates. Complete modeling of the absorption process also required data for the diffusion coefficient of MDEA in water. These were measured using a Taylor dispersion apparatus. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate and protonated MDEA were obtained at 298.2 K and 318.2 K in solutions containing 20, 35, and 50 mass % MDEA in water.« less

Decomposition of carbon dioxide by recombining hydrogen plasma with ultralow electron temperature

NASA Astrophysics Data System (ADS)

Yamazaki, Masahiro; Nishiyama, Shusuke; Sasaki, Koichi

2018-06-01

We examined the rate coefficient for the decomposition of CO2 in low-pressure recombining hydrogen plasmas with electron temperatures between 0.15 and 0.45 eV, where the electron-impact dissociation was negligible. By using this ultralow-temperature plasma, we clearly observed decomposition processes via vibrational excited states. The rate coefficient of the overall reaction, CO2 + e → products, was 1.5 × 10‑17 m3/s in the ultralow-temperature plasma, which was 10 times larger than the decomposition rate coefficient of 2 × 10‑18 m3/s in an ionizing plasma with an electron temperature of 4 eV.

Urban increments of gaseous and aerosol pollutants and their sources using mobile aerosol mass spectrometry measurements

NASA Astrophysics Data System (ADS)

Elser, Miriam; Bozzetti, Carlo; El-Haddad, Imad; Maasikmets, Marek; Teinemaa, Erik; Richter, Rene; Wolf, Robert; Slowik, Jay G.; Baltensperger, Urs; Prévôt, André S. H.

2016-06-01

Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially resolved detailed characterization of PM2.5 (particulate matter with aerodynamic equivalent diameter daero ≤ 2.5 µm) in two major Estonian cities, Tallinn and Tartu. The measurements were performed in March 2014 using a mobile platform. In both cities, the non-refractory (NR)-PM2.5 was characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were also measured. The chemical composition of PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning), and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during nighttime, explaining on average half of the OA mass, while during daytime mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from northern Germany, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and the assessment of the extent to which pollutants concentrations exceeded regional background levels (urban increments). HOA, eBC, CO2, and CO showed stronger enhancements on busy roads during the morning and evening traffic rush hours; BBOA had its maximum enhancement in the residential areas during the evening hours and RIOA was enhanced in both the city center (emissions from restaurants) and in the residential areas (emissions from residential cooking). In contrast, secondary components (OOA, sulfate (SO4), nitrate (NO3), ammonium (NH4), and chloride (Cl)) had very homogeneous distributions in time and space. We were able to determine a total PM2.5 urban increment in Tartu of 6.0 µg m-3 over a regional background concentration of 4.0 µg m-3 (i.e., a factor of 2.5 increase). Traffic exhaust emissions were identified as the most important source of this increase, with eBC and HOA explaining on average 53.3 and 20.5 % of the total increment, respectively.

Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements

NASA Astrophysics Data System (ADS)

Paris, J.-D.; Stohl, A.; Nédélec, P.; Arshinov, M. Yu.; Panchenko, M. V.; Shmargunov, V. P.; Law, K. S.; Belan, B. D.; Ciais, P.

2009-12-01

We present airborne measurements of carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), equivalent black carbon (EBC) and ultra fine particles over North-Eastern Siberia in July 2008 performed during the YAK-AEROSIB/POLARCAT experiment. During a "golden day" (11 July 2008) a number of biomass burning plumes were encountered with CO mixing ratio enhancements of up to 500 ppb relative to a background of 90 ppb. Number concentrations of aerosols in the size range 3.5-200 nm peaked at 4000 cm-3 and the EBC content reached 1.4 μg m-3. These high concentrations were caused by forest fires in the vicinity of the landing airport in Yakutsk where measurements in fresh smoke could be made during the descent. We estimate a combustion efficiency of 90 ± 3% based on CO and CO2 measurements and a CO emission factor of 65.5 ± 10.8 g CO per kilogram of dry matter burned. This suggests a potential increase in the average northern hemispheric CO mixing ratio of 3.0-7.2 ppb per million hectares of Siberian forest burned. For BC, we estimate an emission factor of 0.52 ± 0.07 g BC kg-1, comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5-200 nm) was 26 cm-3 (ppb CO)-1, consistent with other airborne studies. The transport of identified biomass burning plumes was investigated using the FLEXPART Lagrangian model. Based on sampling of wildfire plumes from the same source but with different atmospheric ages derived from FLEXPART, we estimate that the e-folding lifetimes of EBC and ultra fine particles (between 3.5 and 200 nm in size) against removal and growth processes are 5.1 and 5.5 days respectively, supporting lifetime estimates used in various modelling studies.

Caracterisation experimentale et numerique de la flamme de carburants synthetiques gazeux

NASA Astrophysics Data System (ADS)

Ouimette, Pascale

The goal of this research is to characterize experimentally and numerically laminar flames of syngas fuels made of hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2). More specifically, the secondary objectives are: 1) to understand the effects of CO2 concentration and H2/CO ratio on NOx emissions, flame temperature, visible flame height, and flame appearance; 2) to analyze the influence of H2/CO ratio on the lame structure, and; 3) to compare and validate different H2/CO kinetic mechanisms used in a CFD (computational fluid dynamics) model over different H2/CO ratios. Thus, the present thesis is divided in three chapters, each one corresponding to a secondary objective. For the first part, experimentations enabled to conclude that adding CO2 diminishes flame temperature and EINOx for all equivalence ratios while increasing the H2/CO ratio has no influence on flame temperature but increases EINOx for equivalence ratios lower than 2. Concerning flame appearance, a low CO2 concentration in the fuel or a high H2/CO ratio gives the flame an orange color, which is explained by a high level of CO in the combustion by-products. The observed constant flame temperature with the addition of CO, which has a higher adiabatic flame temperature, is mainly due to the increased heat loss through radiation by CO2. Because NOx emissions of H2/CO/CO 2 flames are mainly a function of flame temperature, which is a function of the H2/CO ratio, the rest of the thesis concentrates on measuring and predicting species in the flame as a good prediction of species and heat release will enable to predict NOx emissions. Thus, for the second part, different H2/CO fuels are tested and major species are measured by Raman spectroscopy. Concerning major species, the maximal measured H 2O concentration decreases with addition of CO to the fuel, while the central CO2 concentration increases, as expected. However, at 20% of the visible flame height and for all fuels tested herein, the measured CO2 concentration is lower than its stoechiometric value while the measured H2O already reached its stoechiometric concentration. The slow chemical reactions necessary to produce CO2 compared to the ones forming H2O could explain this difference. For the third part, a numerical model is created for a partially premixed flame of 50% H 2 / 50% CO. This model compares different combustion mechanisms and shows that a reduced kinetic mechanism reduces simulation times while conserving the results quality of more complex kinetic schemes. This numerical model, which includes radiation heat losses, is also validated for a large range of fuels going from 100% H2 to 5% H2 / 95% CO. The most important recommendation of this work is to include a NOx mechanism to the numerical model in order to eventually determine an optimal fuel. It would also be necessary to validate the model over a wide range for different parameters such as equivalence ratio, initial temperature and initial pressure.

Basis for the ICRP’s updated biokinetic model for carbon inhaled as CO 2

DOE PAGES

Leggett, Richard W.

2017-03-02

Here, the International Commission on Radiological Protection (ICRP) is updating its biokinetic and dosimetric models for occupational intake of radionuclides (OIR) in a series of reports called the OIR series. This paper describes the basis for the ICRP's updated biokinetic model for inhalation of radiocarbon as carbon dioxide (CO 2) gas. The updated model is based on biokinetic data for carbon isotopes inhaled as carbon dioxide or injected or ingested as bicarbonatemore » $$({{{\\rm{HCO}}}_{3}}^{-}).$$ The data from these studies are expected to apply equally to internally deposited (or internally produced) carbon dioxide and bicarbonate based on comparison of excretion rates for the two administered forms and the fact that carbon dioxide and bicarbonate are largely carried in a common form (CO 2–H$${{{\\rm{CO}}}_{3}}^{-})$$ in blood. Compared with dose estimates based on current ICRP biokinetic models for inhaled carbon dioxide or ingested carbon, the updated model will result in a somewhat higher dose estimate for 14C inhaled as CO 2 and a much lower dose estimate for 14C ingested as bicarbonate.« less

Basis for the ICRP’s updated biokinetic model for carbon inhaled as CO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leggett, Richard W.

Here, the International Commission on Radiological Protection (ICRP) is updating its biokinetic and dosimetric models for occupational intake of radionuclides (OIR) in a series of reports called the OIR series. This paper describes the basis for the ICRP's updated biokinetic model for inhalation of radiocarbon as carbon dioxide (CO 2) gas. The updated model is based on biokinetic data for carbon isotopes inhaled as carbon dioxide or injected or ingested as bicarbonatemore » $$({{{\\rm{HCO}}}_{3}}^{-}).$$ The data from these studies are expected to apply equally to internally deposited (or internally produced) carbon dioxide and bicarbonate based on comparison of excretion rates for the two administered forms and the fact that carbon dioxide and bicarbonate are largely carried in a common form (CO 2–H$${{{\\rm{CO}}}_{3}}^{-})$$ in blood. Compared with dose estimates based on current ICRP biokinetic models for inhaled carbon dioxide or ingested carbon, the updated model will result in a somewhat higher dose estimate for 14C inhaled as CO 2 and a much lower dose estimate for 14C ingested as bicarbonate.« less

Effect of work intensity on time delay in mediation of ventilation by arterial carbon dioxide during recovery from impulse exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C S; Shirakawa, K; Yunoki, T; Yano, T

2014-01-01

Time delay in the mediation of ventilation (V(.)E) by arterial CO(2) pressure (PaCO(2)) was studied during recovery from short impulse-like exercises with different work loads of recovery. Subjects performed two tests including 10-s impulse like exercise with work load of 200 watts and 15-min recovery with 25 watts in test one and 50 watts in test two. V(.)E, end tidal CO(2) pressure (PETCO(2)) and heart rate (HR) were measured continuously during rest, warming up, exercise and recovery. PaCO(2) was estimated from PETCO(2) and tidal volume (V(T)). Results showed that predicted arterial CO(2) pressure (PaCO(2 pre)) increased during recovery in both tests. In both tests, V(.)E increased and peaked at the end of exercise. V(.)E decreased in the first few seconds of recovery but started to increase again. The highest correlation coefficient between PaCO(2 pre) and V(.)E was obtained in the time delay of 7 s (r=0.854) in test one and in time delays of 6 s (r=0.451) and 31 s (r=0.567) in test two. HR was significantly higher in test two than in test one. These results indicate that PaCO(2 pre) drives V(.)E with a time delay and that higher work intensity induces a shorter time delay.

Direct and reversible hydrogenation of CO2 to formate by a bacterial carbon dioxide reductase.

PubMed

Schuchmann, K; Müller, V

2013-12-13

Storage and transportation of hydrogen is a major obstacle for its use as a fuel. An increasingly considered alternative for the direct handling of hydrogen is to use carbon dioxide (CO2) as an intermediate storage material. However, CO2 is thermodynamically stable, and developed chemical catalysts often require high temperatures, pressures, and/or additives for high catalytic rates. Here, we present the discovery of a bacterial hydrogen-dependent carbon dioxide reductase from Acetobacterium woodii directly catalyzing the hydrogenation of CO2. We also demonstrate a whole-cell system able to produce formate as the sole end product from dihydrogen (H2) and CO2 as well as syngas. This discovery opens biotechnological alternatives for efficient CO2 hydrogenation either by using the isolated enzyme or by employing whole-cell catalysis.

The effect of heterogeneity identifying the leakage of carbon dioxide in a shallow aquifer: an experimental study

NASA Astrophysics Data System (ADS)

Ha, S. W.; Lee, S. H.; Jeon, W. T.; Joo, Y. J.; Lee, K. K.

2014-12-01

Carbon dioxide (CO2) leakage into the shallow aquifer is one of the main concerns at a CO2 sequestration site. Various hydrogeochemical parameters have been suggested to determine the leakage (i.e., pH, EC, Alkalinity, Ca and δ13C). For the practical point of view, direct and continuous measurement of the dissolved CO2 concentration at the proper location can be the most useful strategy for the CO2 leakage detection in a shallow aquifer. In order to enhance possibility of identifying leaked CO2, monitoring location should be determined with regard to the shallow aquifer heterogeneity. In this study, a series of experiments were conducted to investigate the effects of heterogeneity on the dissolved CO2 concentrations. A 2-D sand tank of homogeneous medium sands including a single heterogeneity layer was designed. Two NDIR CO2 sensors, modified for continuous measuring in aquatic system, were installed above and below the single heterogeneous layer (clay, fine and medium sand lenses). Also, temperature and water contents were measured continuously at a same position. Bromocresol purple which is one of the acid-base indicator was used to visualize CO2 migration. During the gas phase CO2 injection at the bottom of the sand tank, dissolved CO2 in the water is continuously measured. In the results, significant differences of concentrations were observed due to the presence of heterogeneity layer, even the locations were close. These results suggested that monitoring location should be determined considering vertical heterogeneity of shallow aquifer at a CO2 leakage site.

Carbon dioxide-water clathrate as a reservoir of CO2 on Mars

NASA Technical Reports Server (NTRS)

Dobrovolskis, A.; Ingersell, A. P.

1975-01-01

It has been suggested that the residual polar caps of Mars contain a resorvoir of permanently frozen carbon dioxide which is controlling the atmospheric pressure. However, observational data and models of the polar heat balance suggest that the temperatures of the Martian poles are too high for solid CO2 to survive permanently. On the other hand, the icelike compound carbon dioxide-water clathrate could function as a CO2 reservoir instead of solid CO2, because it is stable at higher temperatures. This paper shows that the permanent polar caps may contain several millibars of CO2 in the form of clathrate, and discusses the implications of this permanent clathrate reservoir for the present and past atmospheric pressure on Mars.

Environmental Co-Benefit Opportunities of Solar Energy

NASA Astrophysics Data System (ADS)

Hernandez, R. R.; Armstrong, A.; Burney, J. A.; Easter, S. B.; Hoffacker, M. K.; Moore, K. A.

2015-12-01

Solar energy reduces greenhouse gas emissions by an order of magnitude when substituted for fossil fuels. Nonetheless, the strategic deployment of solar energy—from single, rooftop modules to utility-scale solar energy power plants—can confer additional environmental co-benefits beyond its immediate use as a low carbon energy source. In this study, we identify a diverse portfolio of environmental co-benefit opportunities of solar energy technologies resulting from synergistic innovations in land, food, energy, and water systems. For each opportunity, we provide a demonstrative, quantitative framework for environmental co-benefit valuation—including, equations, models, or case studies for estimating carbon dioxide equivalent (CO2-eq) and cost savings ($US) averted by environmental co-benefit opportunities of solar energy—and imminent research questions to improve certainty of valuations. As land-energy-food-water nexus issues are increasingly exigent in 21st century, we show that environmental co-benefit opportunities of solar energy are feasible in numerous environments and at a wide range of spatial scales thereby able to contribute to local and regional environmental goals and for the mitigation of climate change.

Biodiesel production in a semiarid environment: a life cycle assessment approach.

PubMed

Biswas, Wahidul K; Barton, Louise; Carter, Daniel

2011-04-01

While the use of biodiesel appears to be a promising alternative to petroleum fuel, the replacement of fossil fuel by biofuel may not bring about the intended climate cooling because of the increased soil N2O emissions due to N-fertilizer applications. Using a life cycle assessment approach, we assessed the influence of soil nitrous oxide (N2O) emissions on the life cycle global warming potential of the production and combustion of biodiesel from canola oil produced in a semiarid climate. Utilizing locally measured soil N2O emissions, rather than the Intergovernmental Panel on Climate Change (IPCC) default values, decreased greenhouse gas (GHG) emissions from the production and combustion of 1 GJ biodiesel from 63 to 37 carbon dioxide equivalents (CO2-e)/GJ. GHG were 1.1 to 2.1 times lower than those from petroleum or petroleum-based diesel depending on which soil N2O emission factors were included in the analysis. The advantages of utilizing biodiesel rapidly declined when blended with petroleum diesel. Mitigation strategies that decrease emissions from the production and application of N fertilizers may further decrease the life cycle GHG emissions in the production and combustion of biodiesel.

A Novel Method for Determining the Gas Transfer Velocity of Carbon Dioxide in Streams

NASA Astrophysics Data System (ADS)

McDowell, M. J.; Johnson, M. S.

2016-12-01

Characterization of the global carbon cycle relies on the accurate quantification of carbon fluxes into and out of natural and human-dominated ecosystems. Among these fluxes, carbon dioxide (CO2) evasion from surface water has received increasing attention in recent years. However, limitations of current methods, including determination of the gas transfer velocity (k), compromise our ability to evaluate the significance of CO2 fluxes between freshwater systems and the atmosphere. We developed an automated method to determine gas transfer velocities of CO2 (kCO2), and tested it under a range of flow conditions for a first-order stream of a headwater catchment in southwestern British Columbia, Canada. Our method uses continuous in situ measurements of CO2 concentrations using two non-dispersive infrared (NDIR) sensors enclosed in water impermeable, gas permeable membranes (Johnson et al., 2010) downstream from a gas diffuser. CO2 was injected into the stream at regular intervals via a compressed gas tank connected to the diffuser. CO2 injections were controlled by a datalogger at fixed time intervals and in response to storm-induced changes in streamflow. Following the injection, differences in CO2 concentrations at known distances downstream from the diffuser relative to pre-injection baseline levels allowed us to calculate kCO2. Here we present relationships between kCO2 and hydro-geomorphologic (flow velocity, streambed slope, stream width, stream depth), atmospheric (wind speed and direction), and water quality (stream temperature, pH, electrical conductivity) variables. This method has advantages of being automatable and field-deployable, and it does not require supplemental gas chromatography, as is the case for propane injections typically used to determine k. The dataset presented suggests the potential role of this method to further elucidate the role that CO2 fluxes from headwater streams play in the global carbon cycle. Johnson, M. S., Billett, M. F., Dinsmore, K. J., Wallin, M., Dyson, K. E., & Jassal, R. S. (2010). Direct and continuous measurement of dissolved carbon dioxide in freshwater aquatic systems—method and applications. Ecohydrology, 3(1), 68-78. http://doi.org/10.1002/eco.95

SN1 reactions in supercritical carbon dioxide in the presence of alcohols: the role of preferential solvation.

PubMed

Delgado-Abad, Thais; Martínez-Ferrer, Jaime; Acerete, Rafael; Asensio, Gregorio; Mello, Rossella; González-Núñez, María Elena

2016-07-06

Ethanol () inhibits SN1 reactions of alkyl halides in supercritical carbon dioxide (scCO2) and gives no ethers as products. The unexpected behaviour of alcohols in the reaction of alkyl halides with 1,3-dimethoxybenzene () in scCO2 under different conditions is rationalised in terms of Brønsted and Lewis acid-base equilibria of reagents, intermediates, additives and products in a singular solvent characterised by: (i) the strong quadrupole and Lewis acid character of carbon dioxide, which hinders SN2 paths by strongly solvating basic solutes; (ii) the weak Lewis base character of carbon dioxide, which prevents it from behaving as a proton sink; (iii) the compressible nature of scCO2, which enhances the impact of preferential solvation on carbon dioxide availability for the solvent-demanding rate determining step.

Greenhouse Gas Dynamics in a Salt-Wedge Estuary Revealed by High Resolution Cavity Ring-Down Spectroscopy Observations.

PubMed

Tait, Douglas R; Maher, Damien T; Wong, WeiWen; Santos, Isaac R; Sadat-Noori, Mahmood; Holloway, Ceylena; Cook, Perran L M

2017-12-05

Estuaries are an important source of greenhouse gases to the atmosphere, but uncertainties remain in the flux rates and production pathways of greenhouse gases in these dynamic systems. This study performs simultaneous high resolution measurements of the three major greenhouse gases (carbon dioxide, methane, and nitrous oxide) as well as carbon stable isotope ratios of carbon dioxide and methane, above and below the pycnocline along a salt wedge estuary (Yarra River estuary, Australia). We identified distinct zones of elevated greenhouse gas concentrations. At the tip of salt wedge, average CO 2 and N 2 O concentrations were approximately five and three times higher than in the saline mouth of the estuary. In anaerobic bottom waters, the natural tracer radon ( 222 Rn) revealed that porewater exchange was the likely source of the highest methane concentrations (up to 1302 nM). Isotopic analysis of CH 4 showed a dominance of acetoclastic production in fresh surface waters and hydrogenotrophic production occurring in the saline bottom waters. The atmospheric flux of methane (in CO 2 equivalent units) was a major (35-53%) contributor of atmospheric radiative forcing from the estuary, while N 2 O contributed <2%. We hypothesize that the release of bottom water gases when stratification episodically breaks down will release large pulses of greenhouse gases to the atmosphere.

Disintegration of Carbon Dioxide Molecules in a Microwave Plasma Torch

PubMed Central

Kwak, Hyoung S.; Uhm, Han S.; Hong, Yong C.; Choi, Eun H.

2015-01-01

A pure carbon dioxide torch is generated by making use of 2.45 GHz microwave. Carbon dioxide gas becomes the working gas and produces a stable carbon dioxide torch. The torch volume is almost linearly proportional to the microwave power. Temperature of the torch flame is measured by making use of optical spectroscopy and thermocouple. Two distinctive regions are exhibited, a bright, whitish region of high-temperature zone and a bluish, dimmer region of relatively low-temperature zone. Study of carbon dioxide disintegration and gas temperature effects on the molecular fraction characteristics in the carbon dioxide plasma of a microwave plasma torch under atmospheric pressure is carried out. An analytical investigation of carbon dioxide disintegration indicates that substantial fraction of carbon dioxide molecules disintegrate and form other compounds in the torch. For example, the normalized particle densities at center of plasma are given by nCO2/nN = 6.12 × 10−3, nCO/nN = 0.13, nC/nN = 0.24, nO/nN = 0.61, nC2/nN = 8.32 × 10−7, nO2/nN = 5.39 × 10−5, where nCO2, nCO, nC, nO, nC2, and nO2 are carbon dioxide, carbon monoxide, carbon and oxygen atom, carbon and oxygen molecule densities, respectively. nN is the neutral particle density. Emission profiles of the oxygen and carbon atom radicals and the carbon monoxide molecules confirm the theoretical predictions of carbon dioxide disintegration in the torch. PMID:26674957

Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition

PubMed Central

Loladze, Irakli

2014-01-01

Mineral malnutrition stemming from undiversified plant-based diets is a top global challenge. In C3 plants (e.g., rice, wheat), elevated concentrations of atmospheric carbon dioxide (eCO2) reduce protein and nitrogen concentrations, and can increase the total non-structural carbohydrates (TNC; mainly starch, sugars). However, contradictory findings have obscured the effect of eCO2 on the ionome—the mineral and trace-element composition—of plants. Consequently, CO2-induced shifts in plant quality have been ignored in the estimation of the impact of global change on humans. This study shows that eCO2 reduces the overall mineral concentrations (−8%, 95% confidence interval: −9.1 to −6.9, p<0.00001) and increases TNC:minerals > carbon:minerals in C3 plants. The meta-analysis of 7761 observations, including 2264 observations at state of the art FACE centers, covers 130 species/cultivars. The attained statistical power reveals that the shift is systemic and global. Its potential to exacerbate the prevalence of ‘hidden hunger’ and obesity is discussed. DOI: http://dx.doi.org/10.7554/eLife.02245.001 PMID:24867639

Investigations on the Use of Multi-Species Flask Measurements for Sector-Specific Fossil Fuel CO2 Attribution to Aid Policymakers

NASA Astrophysics Data System (ADS)

Nathan, B.; Lauvaux, T.; Turnbull, J. C.; Sweeney, C.; Karion, A.; Richardson, S.; Miles, N.; Gurney, K. R.; Patarasuk, R.

2016-12-01

Part of the Indianapolis Flux (INFLUX) Experiment has, since 2010, involved recording atmospheric trace gas measurements using NOAA flask packages. The goal of these measurements is to better inform policymakers about the behaviors of greenhouse gas emissions in the Indianapolis urban environment. Radiocarbon dioxide (14CO2) measurements recorded from the flasks allow for delineation of the fossil-fuel carbon dioxide (CO2ff) signal from the total carbon dioxide (CO2) measurement. To give policymakers even more detailed information, we investigate whether the co-measured trace gases could be used as tracers for economic source sectors of CO2ff as predefined by the bottom-up data product Hestia. This is extensively tested using an Observation System Simulation Experiment (OSSE) combining both a top-down approach for all species—influence functions from the tower flask measurements—, and attempting to assign sources via spatial overlaps with the available bottom-up inventory CO2ff source sector definitions. A self-organizing map is implemented for the mathematical attribution of signals to sources, because it can compensate for nonlinear signals (i.e. tracer emissions that do not scale linearly with CO2ff emissions). It is determined that proper attribution is at least not feasible with such a complete lack of bottom-up spatial information about all non-CO2ff potential tracers. This unfeasibility is shown not to be resolved by a test of expanding the dataset with many more theoretical measurements than are realistically available. Here we alter the approach to include the missing prior information: bottom-up estimates of the emission fluxes for a suite of species. We develop these bottom-up emission fluxes from existing whole-city emission fluxes, species-specific source sector partitioning, and the spatial patterns from Hestia CO2ff source sectors. We validate the general approach using the whole-city species: CO2ff ratios derived from all tower flask measurements. Finally, using these tools, multi-species, sector-specific inversions are investigated in the Bayesian framework.

Mofettes - Investigation of Natural CO2 Springs - Insights and Methods applied

NASA Astrophysics Data System (ADS)

Lübben, A.; Leven, C.

2014-12-01

The quantification of carbon dioxide concentrations and fluxes leaking from the subsurface into the atmosphere is highly relevant in several research fields such as climate change, CCS, volcanic activity, or earthquake monitoring. Many of the areas with elevated carbon dioxide degassing pose the problem that under the given situation a systematic investigation of the relevant processes is only possible to a limited extent (e.g. in terms of spatial extent, accessibility, hazardous conditions). The upper Neckar valley in Southwest Germany is a region of enhanced natural subsurface CO2 concentrations and mass fluxes of Tertiary volcanic origin. At the beginning of the twentieth century several companies started industrial mining of CO2. The decreasing productivity of the CO2 springs led to the complete shutdown of the industry in 1995 and the existing boreholes were sealed. However, there are evidences that the reservoir, located in the deposits of the Lower Triassic, started to refill during the last 20 years. The CO2 springs replenished and a variety of different phenomena (e.g. mofettes and perished flora and fauna) indicate the active process of large scale CO2 exhalation. This easy-to-access site serves as a perfect example for a natural analog to a leaky CCS site, including abandoned boreholes and a suitable porous rock reservoir in the subsurface. During extensive field campaigns we applied several monitoring techniques like measurements of soil gas concentrations, mass fluxes, electrical resistivity, as well as soil and atmospheric parameters. The aim was to investigate and quantify mass fluxes and the effect of variations in e.g. temperature, soil moisture on the mass flux intensity. Furthermore, we investigated the effect of the vicinity to a mofette on soil parameters like electrical conductivity and soil CO2 concentrations. In times of a changing climate due to greenhouse gases, regions featuring natural CO2 springs demand to be intensively investigated. Our results serve as a contribution to the development of site-specific monitoring networks at CCS sites, as well as a step forward to unravel the share of natural CO2 springs in the global carbon cycle.

Greenhouse gas emissions in the state of Morelos, Mexico: a first approximation for establishing mitigation strategies.

PubMed

Quiroz-Castañeda, Rosa Estela; Sánchez-Salinas, Enrique; Castrejón-Godínez, María Luisa; Ortiz-Hernández, Ma Laura

2013-11-01

In this study, the authors report the first greenhouse gas emission inventory of Morelos, a state in central Mexico, in which the emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) have been identified using the Intergovernmental Panel on Climate Change (IPCC) methodology. Greenhouse gas (GHG) emissions were estimated as CO2 equivalents (CO2 eq) for the years 2005, 2007, and 2009, with 2005 being treated as the base year. The percentage contributions from each category to the CO2 eq emissions in the base year were as follows: 38% from energy, 30% from industrial processes, 23% from waste, 5% from agriculture, and 4% from land use/land use change and forestry (LULUCF). As observed in other state inventories in Mexico, road transportation is the main source of CO2 emissions, wastewater handling and solid waste disposal are the main sources of CH4 emissions, and agricultural soils are the source of the most significant N2O emissions. The information reported in this inventory identifies the main emission sources. Based on these results, the government can propose public policies specifically designed for the state of Morelos to establish GHG mitigation strategies in the near future.

CARBON DIOXIDE SEPARATION BY PHASE ENHANCED GAS-LIQUID ABSORPTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang Hu

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 ofmore » 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.« less

Effects of supercritical carbon dioxide on immobile bound polymer chains on solid substrates

NASA Astrophysics Data System (ADS)

Sen, Mani; Asada, Mitsunori; Jiang, Naisheng; Endoh, Maya K.; Akgun, Bulent; Satija, Sushil; Koga, Tadanori

2013-03-01

Adsorbed polymer layers formed on flat solid substrates have recently been the subject of extensive studies because it is postulated to control the dynamics of technologically relevant polymer thin films, for example, in lithography. Such adsorbed layers have been reported to hinder the mobility of polymer chains in thin films even at a large length scale. Consequently, this bound layer remains immobile regardless of processing techniques (i.e. thermal annealing, solvent dissolution, etc). Here, we investigate the use of supercritical carbon dioxide (scCO2) as a novel plasticizer for bound polystyrene layers formed on silicon substrates. In-situ swelling and interdiffusion experiments using neutron reflectivity were performed. As a result, we found the anomalous plasticization effects of scCO2 on the bound polymer layers near the critical point where the anomalous adsorption of CO2 molecules in polymer thin films has been reported previously. Acknowledgement: We acknowledge the financial support from NSF Grant No. CMMI-084626.

Sellers works at the CO2 Absorber Panel Door in the MDDK during STS-132

NASA Image and Video Library

2010-05-15

S132-E-007167 (15 May 2010) --- NASA astronaut Piers Sellers, STS-132 mission specialist, works at the Carbon Dioxide absorber panel door on the middeck of the Earth-orbiting space shuttle Atlantis during Flight Day 2 activities. Photo credit: NASA or National Aeronautics and Space Administration

Laboratory evaluation of surface amendments for controlling greenhouse gas emissions from beef cattle feedlots.

USDA-ARS?s Scientific Manuscript database

Pen surface amendments for mitigating emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from beef cattle feedlots, were evaluated under controlled laboratory conditions. Amendments were organic residues (i.e., sorghum straw, prairie grass, wo...

Fossil-Fuel C02 Emissions Database and Exploration System

NASA Astrophysics Data System (ADS)

Krassovski, M.; Boden, T.

2012-04-01

Fossil-Fuel C02 Emissions Database and Exploration System Misha Krassovski and Tom Boden Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL) quantifies the release of carbon from fossil-fuel use and cement production each year at global, regional, and national spatial scales. These estimates are vital to climate change research given the strong evidence suggesting fossil-fuel emissions are responsible for unprecedented levels of carbon dioxide (CO2) in the atmosphere. The CDIAC fossil-fuel emissions time series are based largely on annual energy statistics published for all nations by the United Nations (UN). Publications containing historical energy statistics make it possible to estimate fossil-fuel CO2 emissions back to 1751 before the Industrial Revolution. From these core fossil-fuel CO2 emission time series, CDIAC has developed a number of additional data products to satisfy modeling needs and to address other questions aimed at improving our understanding of the global carbon cycle budget. For example, CDIAC also produces a time series of gridded fossil-fuel CO2 emission estimates and isotopic (e.g., C13) emissions estimates. The gridded data are generated using the methodology described in Andres et al. (2011) and provide monthly and annual estimates for 1751-2008 at 1° latitude by 1° longitude resolution. These gridded emission estimates are being used in the latest IPCC Scientific Assessment (AR4). Isotopic estimates are possible thanks to detailed information for individual nations regarding the carbon content of select fuels (e.g., the carbon signature of natural gas from Russia). CDIAC has recently developed a relational database to house these baseline emissions estimates and associated derived products and a web-based interface to help users worldwide query these data holdings. Users can identify, explore and download desired CDIAC fossil-fuel CO2 emissions data. This presentation introduces the architecture and design of the new relational database and web interface, summarizes the present state and functionality of the Fossil-Fuel CO2 Emissions Database and Exploration System, and highlights future plans for expansion of the relational database and interface.

Climate change mitigation through livestock system transitions.

PubMed

Havlík, Petr; Valin, Hugo; Herrero, Mario; Obersteiner, Michael; Schmid, Erwin; Rufino, Mariana C; Mosnier, Aline; Thornton, Philip K; Böttcher, Hannes; Conant, Richard T; Frank, Stefan; Fritz, Steffen; Fuss, Sabine; Kraxner, Florian; Notenbaert, An

2014-03-11

Livestock are responsible for 12% of anthropogenic greenhouse gas emissions. Sustainable intensification of livestock production systems might become a key climate mitigation technology. However, livestock production systems vary substantially, making the implementation of climate mitigation policies a formidable challenge. Here, we provide results from an economic model using a detailed and high-resolution representation of livestock production systems. We project that by 2030 autonomous transitions toward more efficient systems would decrease emissions by 736 million metric tons of carbon dioxide equivalent per year (MtCO2e⋅y(-1)), mainly through avoided emissions from the conversion of 162 Mha of natural land. A moderate mitigation policy targeting emissions from both the agricultural and land-use change sectors with a carbon price of US$10 per tCO2e could lead to an abatement of 3,223 MtCO2e⋅y(-1). Livestock system transitions would contribute 21% of the total abatement, intra- and interregional relocation of livestock production another 40%, and all other mechanisms would add 39%. A comparable abatement of 3,068 MtCO2e⋅y(-1) could be achieved also with a policy targeting only emissions from land-use change. Stringent climate policies might lead to reductions in food availability of up to 200 kcal per capita per day globally. We find that mitigation policies targeting emissions from land-use change are 5 to 10 times more efficient--measured in "total abatement calorie cost"--than policies targeting emissions from livestock only. Thus, fostering transitions toward more productive livestock production systems in combination with climate policies targeting the land-use change appears to be the most efficient lever to deliver desirable climate and food availability outcomes.

Climate change mitigation through livestock system transitions

PubMed Central

Havlík, Petr; Valin, Hugo; Herrero, Mario; Obersteiner, Michael; Schmid, Erwin; Rufino, Mariana C.; Mosnier, Aline; Thornton, Philip K.; Böttcher, Hannes; Conant, Richard T.; Frank, Stefan; Fritz, Steffen; Fuss, Sabine; Kraxner, Florian; Notenbaert, An

2014-01-01

Livestock are responsible for 12% of anthropogenic greenhouse gas emissions. Sustainable intensification of livestock production systems might become a key climate mitigation technology. However, livestock production systems vary substantially, making the implementation of climate mitigation policies a formidable challenge. Here, we provide results from an economic model using a detailed and high-resolution representation of livestock production systems. We project that by 2030 autonomous transitions toward more efficient systems would decrease emissions by 736 million metric tons of carbon dioxide equivalent per year (MtCO2e⋅y−1), mainly through avoided emissions from the conversion of 162 Mha of natural land. A moderate mitigation policy targeting emissions from both the agricultural and land-use change sectors with a carbon price of US$10 per tCO2e could lead to an abatement of 3,223 MtCO2e⋅y−1. Livestock system transitions would contribute 21% of the total abatement, intra- and interregional relocation of livestock production another 40%, and all other mechanisms would add 39%. A comparable abatement of 3,068 MtCO2e⋅y−1 could be achieved also with a policy targeting only emissions from land-use change. Stringent climate policies might lead to reductions in food availability of up to 200 kcal per capita per day globally. We find that mitigation policies targeting emissions from land-use change are 5 to 10 times more efficient—measured in “total abatement calorie cost”—than policies targeting emissions from livestock only. Thus, fostering transitions toward more productive livestock production systems in combination with climate policies targeting the land-use change appears to be the most efficient lever to deliver desirable climate and food availability outcomes. PMID:24567375

Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

NASA Astrophysics Data System (ADS)

Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

2015-12-01

Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

NASA Astrophysics Data System (ADS)

Tang, Nicholas W.; Apte, Joshua S.; Martien, Philip T.; Kirchstetter, Thomas W.

2015-08-01

Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate ;head-end; power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

Proposed Trace Gas Measurements Over the Western United States for TROPOMI Validation

NASA Technical Reports Server (NTRS)

Parworth, Caroline L.; Marrero, Josette E.; Yates, Emma L.; Ryoo, Ju-Mee; Iraci, Laura T.

2018-01-01

The Alpha Jet Atmospheric eXperiment (AJAX), located in the Bay Area of California, is a joint effort between NASA Ames Research Center and H211, LCC. AJAX makes in-situ airborne measurements of trace gases 2-4 times per month, resulting in over 216 flights since 2011. Current measurements include ozone (O3), carbon dioxide (CO2), methane (CH4), water (H2O), formaldehyde (HCHO), and meteorological measurements (i.e., ambient pressure, temperature, and 3D winds). Currently, the AJAX team is working to incorporate nitrogen dioxide (NO2) measurements with a Cavity Attenuated Phase Shift Spectrometer (CAPS). Successful science flights coincident with satellite overpasses have been performed since 2011 by the Alpha Jet, with more than 40 flights under the Greenhouse Observing SATellite (GOSAT) and several flights under the Orbiting Carbon Observatory-2 (OCO-2). Results from these flights, which have covered a range of different surfaces and seasonal conditions, will be presented. In-situ vertical profiles of O3, CO2, CH4, H2O, HCHO, and NO2 from the surface to 28,000 feet made by AJAX will also be valuable for satellite validation of data products obtained from the TROPOspheric Montoring Instrument (TROPOMI). TROPOMI is on board the Copernicus Sentinel-5 precursor (S5p) satellite, with level 2 products including O3, CO, CH4, HCHO, NO2, and aerosols.

Supercritical carbon dioxide for textile applications and recent developments

NASA Astrophysics Data System (ADS)

Eren, H. A.; Avinc, O.; Eren, S.

2017-10-01

In textile industry, supercritical carbon dioxide (scCO2), possessing liquid-like densities, mostly find an application on textile dyeing processes such as providing hydrophobic dyes an advantage on dissolving. Their gas-like low viscosities and diffusion properties can result in shorter dyeing periods in comparison with the conventional water dyeing process. Supercritical carbon dioxide dyeing is an anhydrous dyeing and this process comprises the usage of less energy and chemicals when compared to conventional water dyeing processes leading to a potential of up to 50% lower operation costs. The advantages of supercritical carbon dioxide dyeing method especially on synthetic fiber fabrics hearten leading textile companies to alter their dyeing method to this privileged waterless dyeing technology. Supercritical carbon dioxide (scCO2) waterless dyeing is widely known and applied green method for sustainable and eco-friendly textile industry. However, not only the dyeing but also scouring, desizing and different finishing applications take the advantage of supercritical carbon dioxide (scCO2). In this review, not only the principle, advantages and disadvantages of dyeing in supercritical carbon dioxide but also recent developments of scCO2 usage in different textile processing steps such as scouring, desizing and finishing are explained and commercial developments are stated and summed up.

Fertilizer application timing influences greenhouse gas fluxes over a growing season.

PubMed

Phillips, Rebecca L; Tanaka, Donald L; Archer, David W; Hanson, Jon D

2009-01-01

Microbial production and consumption of greenhouse gases (GHG) is influenced by temperature and nutrients, especially during the first few weeks after agricultural fertilization. The effect of fertilization on GHG fluxes should occur during and shortly after application, yet data indicating how application timing affects both GHG fluxes and crop yields during a growing season are lacking. We designed a replicated (n = 5) field experiment to test for the short-term effect of fertilizer application timing on fluxes of methane (CH(4)), carbon dioxide (CO(2)), and nitrous oxide (N(2)O) over a growing season in the northern Great Plains. Each 0.30-ha plot was planted to maize (Zea mays L.) and treated similarly with the exception of fertilizer timing: five plots were fertilized with urea in early spring (1 April) and five plots were fertilized with urea in late spring (13 May). We hypothesized time-integrated fluxes over a growing season would be greater for the late-spring treatment, resulting in a greater net GHG flux, as compared to the early-spring treatment. Data collected on 59 dates and integrated over a 5-mo time course indicated CO(2) fluxes were greater (P < 0.0001) and CH(4) fluxes were lower (P < 0.05) for soils fertilized in late spring. Net GHG flux was also significantly affected by treatment, with 0.84 +/- 0.11 kg CO(2) equivalents m(-2) for early spring and 1.04 +/- 0.13 kg CO(2) equivalents m(-2) for late spring. Nitrous oxide fluxes, however, were similar for both treatments. Results indicate fertilizer application timing influences net GHG emissions in dryland cropping systems.

The Efficacy and Potential of Renewable Energy from Carbon Dioxide that is Sequestered in Sedimentary Basin Geothermal Resources

NASA Astrophysics Data System (ADS)

Bielicki, J. M.; Adams, B. M.; Choi, H.; Saar, M. O.; Taff, S. J.; Jamiyansuren, B.; Buscheck, T. A.; Ogland-Hand, J.

2015-12-01

Mitigating climate change requires increasing the amount of electricity that is generated from renewable energy technologies and while simultaneously reducing the amount of carbon dioxide (CO2) that is emitted to the atmosphere from present energy and industrial facilities. We investigated the efficacy of generating electricity using renewable geothermal heat that is extracted by CO2 that is sequestered in sedimentary basins. To determine the efficacy of CO2-Geothermal power production in the United States, we conducted a geospatial resource assessment of the combination of subsurface CO2 storage capacity and heat flow in sedimentary basins and developed an integrated systems model that combines reservoir modeling with power plant modeling and economic costs. The geospatial resource assessment estimates the potential resource base for CO2-Geothermal power plants, and the integrated systems model estimates the physical (e.g., net power) and economic (e.g., levelized cost of electricity, capital cost) performance of an individual CO2-Geothermal power plant for a range of reservoir characteristics (permeability, depth, geothermal temperature gradient). Using coupled inverted five-spot injection patterns that are common in CO2-enhanced oil recovery operations, we determined the well pattern size that best leveraged physical and economic economies of scale for the integrated system. Our results indicate that CO2-Geothermal plants can be cost-effectively deployed in a much larger region of the United States than typical approaches to geothermal electricity production. These cost-effective CO2-Geothermal electricity facilities can also be capacity-competitive with many existing baseload and renewable energy technologies over a range of reservoir parameters. For example, our results suggest that, given the right combination of reservoir parameters, LCOEs can be as low as $25/MWh and capacities can be as high as a few hundred MW.

Climate adaptation as mitigation: the case of agricultural investments

NASA Astrophysics Data System (ADS)

Lobell, David B.; Baldos, Uris Lantz C.; Hertel, Thomas W.

2013-03-01

Successful adaptation of agriculture to ongoing climate changes would help to maintain productivity growth and thereby reduce pressure to bring new lands into agriculture. In this paper we investigate the potential co-benefits of adaptation in terms of the avoided emissions from land use change. A model of global agricultural trade and land use, called SIMPLE, is utilized to link adaptation investments, yield growth rates, land conversion rates, and land use emissions. A scenario of global adaptation to offset negative yield impacts of temperature and precipitation changes to 2050, which requires a cumulative 225 billion USD of additional investment, results in 61 Mha less conversion of cropland and 15 Gt carbon dioxide equivalent (CO2e) fewer emissions by 2050. Thus our estimates imply an annual mitigation co-benefit of 0.35 GtCO2e yr-1 while spending 15 per tonne CO2e of avoided emissions. Uncertainty analysis is used to estimate a 5-95% confidence interval around these numbers of 0.25-0.43 Gt and 11-22 per tonne CO2e. A scenario of adaptation focused only on Sub-Saharan Africa and Latin America, while less costly in aggregate, results in much smaller mitigation potentials and higher per tonne costs. These results indicate that although investing in the least developed areas may be most desirable for the main objectives of adaptation, it has little net effect on mitigation because production gains are offset by greater rates of land clearing in the benefited regions, which are relatively low yielding and land abundant. Adaptation investments in high yielding, land scarce regions such as Asia and North America are more effective for mitigation. To identify data needs, we conduct a sensitivity analysis using the Morris method (Morris 1991 Technometrics 33 161-74). The three most critical parameters for improving estimates of mitigation potential are (in descending order) the emissions factors for converting land to agriculture, the price elasticity of land supply with respect to land rents, and the elasticity of substitution between land and non-land inputs. For assessing the mitigation costs, the elasticity of productivity with respect to investments in research and development is also very important. Overall, this study finds that broad-based efforts to adapt agriculture to climate change have mitigation co-benefits that, even when forced to shoulder the entire expense of adaptation, are inexpensive relative to many activities whose main purpose is mitigation. These results therefore challenge the current approach of most climate financing portfolios, which support adaptation from funds completely separate from—and often much smaller than—mitigation ones.

Liquid carbon dioxide absorbents, methods of using the same, and related system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perry, Robert James; Soloveichik, Grigorii Lev; Rubinsztajn, Malgorzata Iwona

A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO 2 or have a high-affinity for CO 2, and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO 2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

Liquid carbon dioxide absorbents, methods of using the same, and related systems

DOEpatents

O'Brien, Michael Joseph; Perry, Robert James; Lam, Tunchiao Hubert; Soloveichik, Grigorii Lev; Kniajanski, Sergei; Lewis, Larry Neil; Rubinsztajn, Malgorzata Iwona; Hancu, Dan

2016-09-13

A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO.sub.2 or have a high-affinity for CO.sub.2; and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO.sub.2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

The phylogenetic composition and structure of soil microbial communities shifts in response to elevated carbon dioxide.

PubMed

He, Zhili; Piceno, Yvette; Deng, Ye; Xu, Meiying; Lu, Zhenmei; Desantis, Todd; Andersen, Gary; Hobbie, Sarah E; Reich, Peter B; Zhou, Jizhong

2012-02-01

One of the major factors associated with global change is the ever-increasing concentration of atmospheric CO(2). Although the stimulating effects of elevated CO(2) (eCO(2)) on plant growth and primary productivity have been established, its impacts on the diversity and function of soil microbial communities are poorly understood. In this study, phylogenetic microarrays (PhyloChip) were used to comprehensively survey the richness, composition and structure of soil microbial communities in a grassland experiment subjected to two CO(2) conditions (ambient, 368 p.p.m., versus elevated, 560 p.p.m.) for 10 years. The richness based on the detected number of operational taxonomic units (OTUs) significantly decreased under eCO(2). PhyloChip detected 2269 OTUs derived from 45 phyla (including two from Archaea), 55 classes, 99 orders, 164 families and 190 subfamilies. Also, the signal intensity of five phyla (Crenarchaeota, Chloroflexi, OP10, OP9/JS1, Verrucomicrobia) significantly decreased at eCO(2), and such significant effects of eCO(2) on microbial composition were also observed at the class or lower taxonomic levels for most abundant phyla, such as Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Acidobacteria, suggesting a shift in microbial community composition at eCO(2). Additionally, statistical analyses showed that the overall taxonomic structure of soil microbial communities was altered at eCO(2). Mantel tests indicated that such changes in species richness, composition and structure of soil microbial communities were closely correlated with soil and plant properties. This study provides insights into our understanding of shifts in the richness, composition and structure of soil microbial communities under eCO(2) and environmental factors shaping the microbial community structure.

Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium.

PubMed

Salimi, Kouroush; Yilmaz, Mehmet; Rzayev, Zakir M O; Piskin, Erhan

2014-12-19

This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global CO2 emissions from cement production

NASA Astrophysics Data System (ADS)

Andrew, Robbie M.

2018-01-01

The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 Gt CO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831455.

The social inefficiency of regulating indirect land use change due to biofuels

PubMed Central

Khanna, Madhu; Wang, Weiwei; Hudiburg, Tara W.; DeLucia, Evan H.

2017-01-01

Efforts to reduce the indirect land use change (ILUC) -related carbon emissions caused by biofuels has led to inclusion of an ILUC factor as a part of the carbon intensity of biofuels in a Low Carbon Fuel Standard. While previous research has provided varying estimates of this ILUC factor, there has been no research examining the economic effects and additional carbon savings from including this factor in implementing a Low Carbon Fuel Standard. Here we show that inclusion of an ILUC factor in a national Low Carbon Fuel Standard led to additional abatement of cumulative emissions over 2007–2027 by 1.3 to 2.6% (0.6–1.1 billion mega-grams carbon-dioxide-equivalent (Mg CO2e−1) compared to those without an ILUC factor, depending on the ILUC factors utilized. The welfare cost to the US of this additional abatement ranged from $61 to $187 Mg CO2e−1 and was substantially greater than the social cost of carbon of $50 Mg CO2e−1. PMID:28649991

Laying hen responses to acute heat stress and carbon dioxide supplementation: I. Blood gas changes and plasma lactate accumulation.

PubMed

Koelkebeck, K W; Odom, T W

1994-04-01

Exposure to heat stress lowered partial pressure of arterial blood carbon dioxide (paCO2), arterial blood bicarbonate ion (HCO3-), but increased arterial blood pH (pHa) and plasma lactate (LA). Increasing ambient carbon dioxide (CO2) to 1.5% increased paCO2 from hypocapnic levels to normocapnic levels, raised HCO3-, lowered pHa and plasma LA to pre-heat stress levels. Following CO2 treatment, respiratory alkalosis conditions returned. It was evident in this study that increasing ambient chamber CO2 to 1.5% was effective in ameliorating acid-base disturbances and reducing elevated levels of plasma LA which normally develops when laying hens are subjected to an acute heat stress exposure.

Using dissolved carbon dioxide to alter the behavior of invasive round goby

USGS Publications Warehouse

Cupp, Aaron R.; Tix, John; Smerud, Justin R.; Erickson, Richard A.; Fredricks, Kim; Amberg, Jon J.; Suski, Cory D.; Wakeman, Robert

2017-01-01

Fisheries managers need effective methods to limit the spread of invasive round goby Neogobius melanostomus in North America. Elevating carbon dioxide (CO2) in water at pinch points of rivers (e.g., inside locks) is one approach showing potential to deter the passage of invasive fishes, such as bigheaded carps Hypophthalmichthys spp., but the effectiveness of this method to alter round goby behavior has not been determined. The goal for this study was to determine CO2 concentrations that alter round goby behavior across a range of water temperatures. Free-swimming avoidance (voluntary response) and loss of equilibrium (involuntary response) were quantified by exposing round goby to increasing CO2 concentrations at 5, 15, and 25 °C using a shuttle box choice arena and static tank. Water chemistry was measured concurrent with behavioral endpoints and showed that round goby avoided a threshold of 99–169 mg/L CO2(79,000–178,000 µatm) and lost equilibrium at 197–280 mg/L CO2 (163,000–303,000 µatm). Approximately 50% lower CO2 concentrations were found to modify behavior at 5 °C relative to 25 °C, suggesting greater effectiveness at lower water temperatures. We conclude that CO2 modified round goby behavior and concentrations determined in this study are intended to guide field testing of CO2 as an invasive fish deterrent.

Using semi-analytic solutions to approximate the area of potential impact for carbon dioxide injection

EPA Science Inventory

This study examines using the threshold critical pressure increase and the extent of the carbon dioxide (CO2) plume to delineate the area of potential impact (AoPI) for geologic CO2 storage projects. The combined area covering both the CO2 plume and the region where the pressure ...

Response of sugarcane to carbon dioxide enrichment and elevated air temperature

USDA-ARS?s Scientific Manuscript database

Four sugarcane cultivars (CP 72-2086, CP 73-1547, CP 88-1508, and CP 80-1827) were grown in elongated temperature-gradient greenhouses (TGG) at ambient or elevated carbon dioxide (CO2) of 360 or 720 µmol CO2 mol-1 air (ppm, mole fraction basis), respectively. Elevated CO2 was maintained by injection...

[Correlation between end-tidal carbon dioxide and partial pressure of arterial carbon dioxide in ventilated newborns].

PubMed

Feng, Jin-Xing; Liu, Xiao-Hong; Huang, Hui-Jun; Yu, Zhen-Zhu; Yang, Hui; He, Liu-Fang

2014-05-01

To study the correlation between end-tidal carbon dioxide (PetCO2) and partial pressure of arterial carbon dioxide (PaCO2) in ventilated newborns. Thirty-one ventilated newborn underwent mainstream PetCO2 monitoring; meanwhile, arterial blood gas analysis was performed. The correlation and consistency between PetCO2 and PaCO2 were assessed. A total of 85 end-tidal and arterial CO2 pairs were obtained from 31 ventilated newborns. The mean PetCO2 (41±10 mm Hg) was significantly lower than the corresponding mean PaCO2 (46±11 mm Hg) (P<0.01). There was a significant positive correlation between PetCO2 and PaCO2 (r=0.92, P<0.01). The overall PetCO2 bias was 5.1±4.3 mm Hg (95% limits of consistency, -3.3 to 13.6 mmHg), and 5% (4/85) of the points were beyond the 95%CI. When the oxygenation index (OI) was less than 300 mm Hg (n=48), there was a significant positive correlation between PetCO2 and PaCO2 (r=0.85, P<0.01); the PetCO2 bias was 5.9±4.3 mm Hg (95% limits of consistency, -2.6 to 14.5 mm Hg), and 4.2% (2/48) of the points were beyond the 95%CI. When the OI was more than 300 mm Hg (n=37), there was also a significant positive correlation between PetCO2 and PaCO2 (r=0.91, P<0.01); the PetCO2 bias was 4.1±4.1 mm Hg (95% limits of consistency, -3.9 to 12.1 mm Hg), and 5% (2/37) of the points were beyond the 95%CI. There is a good correlation and consistency between PetCO2 and PaCO2 in ventilated newborns.

Short-Term Effects of Carbon Dioxide on Carnation Callus Cell Respiration 1

PubMed Central

Palet, Artur; Ribas-Carbó, Miquel; Argilés, Josep M.; Azcón-Bieto, Joaquim

1991-01-01

The addition of potassium bicarbonate to the electrode cuvette immediately stimulated the rate of dark O2 uptake of photomixotrophic and heterotrophic carnation (Dianthus caryophyllus L.) callus, of Elodea canadensis (Michx) leaves, and of other plant tissues. This phenomenon occurred at pH values lower than 7.2 to 7.8, and the stimulation depended on the concentration of gaseous CO2 in the solution. These stimulatory responses lasted several minutes and then decreased, but additional bicarbonate or gaseous CO2 again stimulated respiration, suggesting a reversible effect. Carbonic anhydrase in the solution increased the stimulatory effect of potassium bicarbonate. The CO2/bicarbonate dependent stimulation of respiration did not occur in animal tissues such as rat diaphragm and isolated hepatocytes, and was inhibited by salicylhydroxamic acid in carnation callus cells and E. canadensis leaves. This suggested that the alternative oxidase was engaged during the stimulation in plant tissues. The cytochrome pathway was severely inhibited by CO2/bicarbonate either in the absence or in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone. The activity of cytochrome c oxidase of callus tissue homogenates was also inhibited by CO2/bicarbonate. The results suggested that high carbon dioxide levels (mainly free CO2) partially inhibited the cytochrome pathway (apparently at the oxidase level), and this block in electron transport elicited a large transient engagement of the alternative oxidase when present uninhibited. PMID:16668209

The role of carbon dioxide in chemoselective hydrogenation of halonitroaromatics over supported noble metal catalysts in supercritical carbon dioxide.

PubMed

Ichikawa, Shinichiro; Tada, Mizuki; Iwasawa, Yasuhiro; Ikariya, Takao

2005-02-21

Chemoselective hydrogenation of halogenated nitrobenzenes over Pt/C catalysts proceeds effectively in supercritical carbon dioxide (scCO2) to produce halogenated anilines with excellent selectivity; the rate of the hydrogenation of nitro groups is markedly enhanced in scCO2 compared to the neat reaction, and the dehalogenation reaction is significantly suppressed.

NASA launches carbon dioxide research satellite

NASA Astrophysics Data System (ADS)

Wendel, JoAnna

2014-07-01

Last week NASA launched a new satellite to study atmospheric carbon dioxide (CO2). Once in orbit, the Orbiting Carbon Observatory-2 (OCO-2) satellite, launched from Vandenberg Air Force Base in California, will take more than 100,000 individual measurements of atmospheric CO2 per day.

Life Cycle Assessment of Biogas Production in Small-scale Household Digesters in Vietnam

PubMed Central

Vu, T. K. V.; Vu, D. Q.; Jensen, L. S.; Sommer, S. G.; Bruun, S.

2015-01-01

Small-scale household digesters have been promoted across Asia as a sustainable way of handling manure. The major advantages are that they produce biogas and reduce odor. However their disadvantages include the low recycling of nutrients, because digestate is dilute and therefore difficult to transport, and the loss of biogas as a result of cracks and the intentional release of excess biogas. In this study, life cycle assessment (LCA) methodology was used to assess the environmental impacts associated with biogas digesters in Vietnam. Handling 1,000 kg of liquid manure and 100 kg of solid manure in a system with a biogas digester reduced the impact potential from 4.4 kg carbon dioxide (CO2) equivalents to 3.2 kg CO2 equivalents compared with traditional manure management. However, this advantage could easily be compromised if digester construction is considered in the LCA or in situations where there is an excess of biogas which is intentionally released. A sensitivity analysis showed that biogas digesters could be a means of reducing global warming if methane emissions can be kept low. In terms of eutrophication, farms with biogas digesters had 3 to 4 times greater impacts. In order to make biogas digesters sustainable, methods for recycling digestates are urgently required. PMID:25715690

Reproductive allocation in plants as affected by elevated carbon dioxide and other environmental changes: a synthesis using meta-analysis and graphical vector analysis.

PubMed

Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M

2015-04-01

Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future.

Carbon dioxide intercalation in Na-fluorohectorite clay at near-ambient conditions

NASA Astrophysics Data System (ADS)

Fossum, Jon Otto; Hemmen, Henrik; Rolseth, Erlend G.; Fonseca, Davi; Lindbo Hansen, Elisabeth; Plivelic, Tomas

2012-02-01

A molecular dynamics study by Cygan et al.[1] shows the possibility of intercalation and retention of CO2 in smectite clays at 37 ^oC and 200 bar, which suggests that clay minerals may prove suitable for carbon capture and carbon dioxide sequestration. In this work we show from x-ray diffraction measurements that gaseous CO2 intercalates into the interlayer space of the synthetic smectite clay Na-fluorohectorite. The mean interlayer distance of the clay when CO2 is intercalated is 12.5 å at -20 C and 15 bar. The magnitude of the expansion of the interlayer upon intercalation is indistinguishable from that of the dehydrated-monohydrated intercalation of H2O, but this possibility is ruled out by careful repeating the measurements exposing the clay to nitrogen gas. The dynamics of the CO2 intercalation process displays a higher intercalation rate at increased pressure, and the rate is several orders of magnitude slower than that of water or vapor at ambient pressure and temperature.[4pt] [1] Cygan, R. T.; Romanov, V. N.; Myshakin, E. M. Natural materials for carbon capture; Techincal report SAND2010-7217; Sandia National Laboratories: Albuquerque, New Mexico, November, 2010.

Paleobotany and Global Change: Important Lessons for Species to Biomes from Vegetation Responses to Past Global Change.

PubMed

McElwain, Jennifer C

2018-04-29

Human carbon use during the next century will lead to atmospheric carbon dioxide concentrations (pCO 2 ) that have been unprecedented for the past 50-100+ million years according to fossil plant-based CO 2 estimates. The paleobotanical record of plants offers key insights into vegetation responses to past global change, including suitable analogs for Earth's climatic future. Past global warming events have resulted in transient poleward migration at rates that are equivalent to the lowest climate velocities required for current taxa to keep pace with climate change. Paleobiome reconstructions suggest that the current tundra biome is the biome most threatened by global warming. The common occurrence of paleoforests at high polar latitudes when pCO 2 was above 500 ppm suggests that the advance of woody shrub and tree taxa into tundra environments may be inevitable. Fossil pollen studies demonstrate the resilience of wet tropical forests to global change up to 700 ppm CO 2 , contrary to modeled predictions of the future. The paleobotanical record also demonstrates a high capacity for functional trait evolution as an additional strategy to migration and maintenance of a species' climate envelope in response to global change.

Supercritical carbon dioxide: a solvent like no other

PubMed Central

Peach, Jocelyn

2014-01-01

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

Methane production as key to the greenhouse gas budget of thawing permafrost

NASA Astrophysics Data System (ADS)

Knoblauch, Christian; Beer, Christian; Liebner, Susanne; Grigoriev, Mikhail N.; Pfeiffer, Eva-Maria

2018-04-01

Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change1,2. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils3-6 and a stronger permafrost carbon-climate feedback from drained (oxic) soils1,7. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2-Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account8. A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 ± 58 g CO2-C kgC-1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 ± 138 g CO2-Ce kgC-1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.

Climate co-benefits of energy recovery from landfill gas in developing Asian cities: a case study in Bangkok.

PubMed

Menikpura, S N M; Sang-Arun, Janya; Bengtsson, Magnus

2013-10-01

Landfilling is the most common and cost-effective waste disposal method, and it is widely applied throughout the world. In developing countries in Asia there is currently a trend towards constructing sanitary landfills with gas recovery systems, not only as a solution to the waste problem and the associated local environmental pollution, but also to generate revenues through carbon markets and from the sale of electricity. This article presents a quantitative assessment of climate co-benefits from landfill gas (LFG) to energy projects, based on the case of Bangkok Metropolitan Administration, Thailand. Life cycle assessment was used for estimating net greenhouse gas (GHG) emissions, considering the whole lifespan of the landfill. The assessment found that the total GHG mitigation of the Bangkok project would be 471,763 tonnes (t) of carbon dioxide (CO(2))-equivalents (eq) over its 10-year LFG recovery period.This amount is equivalent to only 12% of the methane (CH(4)) generated over the whole lifespan of the landfill. An alternative scenario was devised to analyse possible improvement options for GHG mitigation through LFG-to-energy recovery projects. This scenario assumes that LFG recovery would commence in the second year of landfill operation and gas extraction continues throughout the 20-year peak production period. In this scenario, GHG mitigation potential amounted to 1,639,450 tCO(2)-eq during the 20-year project period, which is equivalent to 43% of the CH(4) generated throughout the life cycle. The results indicate that with careful planning, there is a high potential for improving the efficiency of existing LFG recovery projects which would enhance climate co-benefits, as well as economic benefits. However, the study also shows that even improved gas recovery systems have fairly low recovery rates and, in consequence, that emissions of GHG from such landfills sites are still considerable.

Evaluation of the potentialities to reduce greenhouse gases (GHG) emissions resulting from various treatments of municipal solid wastes (MSW) in moist tropical climates: application to Yaounde.

PubMed

Ngnikam, Emmanuel; Tanawa, Emile; Rousseaux, Patrick; Riedacker, Arthur; Gourdon, Rémy

2002-12-01

The authors here analyse the emission of greenhouse gases (GHG) resulting from the various treatment of municipal solid waste found in the town of Yaounde. Four management systems have been taken as the basis for analyses. System 1 is the traditional collection and landfill disposal, while in system 2 the hiogas produced in the landfill is recuperated to produce electricity. In systems 3 and 4, in addition to the collection, we have introduced a centralised composting or biogas plant before the landfilling disposal of refuse. A Life Cycle Inventory (LCI) of the four systems was made; this enable us to quantify the flux of matter and of energy, consumed or produced by the systems. Following this, only the greenhouse effect was taken into account to evaluate the ecological consequences of the MSW management systems. The method used to evaluate this impact takes into consideration on the one hand, GHG emissions or avoided emission following the substitution of fuel with methane recovered from landfills or produced in the digesters, and on the other hand, sequestrated carbon in the soil following the regular deposit of compost. Landfilling without recuperation of methane is the most emitting solution for greenhouse gas: it leads to the emission of 1.7 ton of carbon dioxide equivalent (tCO2E) per ton of household waste. Composting and methanisation allow one to have a comparable level of emission reduction, either respectively 1.8 and 2 tCO2E/t of MSW. In order to reduce the emission of GHG in the waste management systems, it is advisable to avoid first of all the emissions of methane coming from the landfills. System 2 seems to be a solution that would reduce the emissions of GHG at low cost (2.2 to 4 $/tCO2E). System 2 is calculated as the most effective at the environmental and economic level in the context of Yaounde. Therefore traditional collection, landfill disposal and biogas recuperation to produce electricity is preferable in moist tropical climates.

Sonochemical reduction of carbon dioxide.

PubMed

Harada, H

1998-06-01

Sonolysis of carbon dioxide dissolved in water was performed from a standpoint of reducing this material in atmosphere. During one hour of sonication, the amount of CO2 decreased to about half at 5 degrees C under CO2-Ar atmosphere. The decreasing rate for CO2 followed the order Ar > He > H2 > N2 and it was down with increasing temperature in the range of 5-45 degrees C. The most favorable concentration for reducing CO2 was 0.03 (mole fraction of CO2 in gas phase). This concentration in gas phase means an equal mixture of CO2 and Ar in water, because CO2 is more soluble than Ar. Since carbon dioxide dissolved in water would be partly ionized, the roles of ions on the sonolysis were also examined. Gaseous reaction products were CO, H2 and a small amount of O2. Carbon monoxide and hydrogen might be obtained from CO2 and H2O by sonolysis, respectively. Both gases are fuel and react each other to C1 compounds such as methanol, and so on. Therefore, irradiation of ultrasonic waves should be an important technique for reducing CO2.

Revisiting the social cost of carbon

PubMed Central

Nordhaus, William D.

2017-01-01

The social cost of carbon (SCC) is a central concept for understanding and implementing climate change policies. This term represents the economic cost caused by an additional ton of carbon dioxide emissions or its equivalent. The present study presents updated estimates based on a revised DICE model (Dynamic Integrated model of Climate and the Economy). The study estimates that the SCC is $31 per ton of CO2 in 2010 US$ for the current period (2015). For the central case, the real SCC grows at 3% per year over the period to 2050. The paper also compares the estimates with those from other sources. PMID:28143934

The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance

PubMed Central

Connell, Sean D.; Kroeker, Kristy J.; Fabricius, Katharina E.; Kline, David I.; Russell, Bayden D.

2013-01-01

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO2) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO2] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO2 experiments and data from ‘natural’ volcanic CO2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO2 conditions both in temperate and tropical conditions. The benefits of CO2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects. PMID:23980244

Coupled oxygen-carbon dioxide modelling to partition potential external contribution to stream carbon dioxide concentrations.

NASA Astrophysics Data System (ADS)

Butman, D. E.; Holtgrieve, G. W.

2017-12-01

Recent modelling studies in large catchments have estimated that in excess of 74% of the dissolved carbon dioxide found in first and second order streams originate from allochthonous sources. Stable isotopes of carbon-13 in carbon dioxide have been used to identify ground water seeps in stream systems, where decreases in δ13CO2 occur along gaining stream reaches, suggesting that carbon dioxide in ground water is more depleted than what is found in surface water due to fractionation of CO2 during emissions across the air water interface. Although isotopes represent a chemical tracer in stream systems for potential groundwater contribution, the temporal resolution of discrete samples make partitioning allochthonous versus autochthonous sources of CO2 difficult on hydrologically relevant time scales. Here we show results of field deployments of high frequent dissolved CO2, O2, PAR, Temperature and pH from the Thornton Creek Watershed, the largest urban watershed in Seattle, WA. We present an exploration into using high resolution time series of dissolved oxygen and carbon dioxide in a dual gas approach to separate the contribution of in stream respiration from external sources. We extend upon previous efforts to model stream metabolism across diel cycles by incorporating simultaneous direct measurements of dissolved oxygen, PCO2, and pH within an inverse modeling framework and Bayesian parameter estimation. With an initial assumption of a stoichiometric ratio of 1:1 for O2 and CO2 for autochthonous driven metabolism, we investigate positive or negative departures from this ratio as an indicator of external CO2 to the stream (terrestrial or atmospheric) and factors contributing to this flux.

Temporal and spatial patterns of internal and external stem CO2 fluxes in a sub-Mediterranean oak.

PubMed

Salomón, Roberto L; Valbuena-Carabaña, María; Gil, Luis; McGuire, Mary Anne; Teskey, Robert O; Aubrey, Doug P; González-Doncel, Inés; Rodríguez-Calcerrada, Jesús

2016-11-01

To accurately estimate stem respiration (R S ), measurements of both carbon dioxide (CO 2 ) efflux to the atmosphere (E A ) and internal CO 2 flux through xylem (F T ) are needed because xylem sap transports respired CO 2 upward. However, reports of seasonal dynamics of F T and E A are scarce and no studies exist in Mediterranean species under drought stress conditions. Internal and external CO 2 fluxes at three stem heights, together with radial stem growth, temperature, sap flow and shoot water potential, were measured in Quercus pyrenaica Willd. in four measurement campaigns during one growing season. Substantial daytime depressions in temperature-normalized E A were observed throughout the experiment, including prior to budburst, indicating that diel hysteresis between stem temperature and E A cannot be uniquely ascribed to diversion of CO 2 in the transpiration stream. Low internal [CO 2 ] (<0.5%) resulted in low contributions of F T to R S throughout the growing season, and R S was mainly explained by E A (>90%). Internal [CO 2 ] was found to vary vertically along the stems. Seasonality in resistance to radial CO 2 diffusion was related to shoot water potential. The low internal [CO 2 ] and F T observed in our study may result from the downregulation of xylem respiration in response to a legacy of coppicing as well as high radial diffusion of CO 2 through cambium, phloem and bark tissues, which was related to low water content of stems. Long-term studies analyzing temporal and spatial variation in internal and external CO 2 fluxes and their interactions are needed to mechanistically understand and model respiration of woody tissues. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Origin of the Strong Interaction between Polar Molecules and Copper(II) Paddle-Wheels in Metal Organic Frameworks

DOE PAGES

Ongari, Daniele; Tiana, Davide; Stoneburner, Samuel J.; ...

2017-06-27

The copper paddle-wheel is the building unit of many metal organic frameworks. Because of the ability of the copper cations to attract polar molecules, copper paddle-wheels are promising for carbon dioxide adsorption and separation. They have therefore been studied extensively, both experimentally and computationally. In this work we investigate the copper–CO 2 interaction in HKUST-1 and in two different cluster models of HKUST-1: monocopper Cu(formate) 2 and dicopper Cu 2(formate) 4. We show that density functional theory methods severely underestimate the interaction energy between copper paddle-wheels and CO 2, even including corrections for the dispersion forces. In contrast, a multireferencemore » wave function followed by perturbation theory to second order using the CASPT2 method correctly describes this interaction. The restricted open-shell Møller–Plesset 2 method (ROS-MP2, equivalent to (2,2) CASPT2) was also found to be adequate in describing the system and used to develop a novel force field. Our parametrization is able to predict the experimental CO 2 adsorption isotherms in HKUST-1, and it is shown to be transferable to other copper paddle-wheel systems.« less

Origin of the Strong Interaction between Polar Molecules and Copper(II) Paddle-Wheels in Metal Organic Frameworks.

PubMed

Ongari, Daniele; Tiana, Davide; Stoneburner, Samuel J; Gagliardi, Laura; Smit, Berend

2017-07-20

The copper paddle-wheel is the building unit of many metal organic frameworks. Because of the ability of the copper cations to attract polar molecules, copper paddle-wheels are promising for carbon dioxide adsorption and separation. They have therefore been studied extensively, both experimentally and computationally. In this work we investigate the copper-CO 2 interaction in HKUST-1 and in two different cluster models of HKUST-1: monocopper Cu(formate) 2 and dicopper Cu 2 (formate) 4 . We show that density functional theory methods severely underestimate the interaction energy between copper paddle-wheels and CO 2 , even including corrections for the dispersion forces. In contrast, a multireference wave function followed by perturbation theory to second order using the CASPT2 method correctly describes this interaction. The restricted open-shell Møller-Plesset 2 method (ROS-MP2, equivalent to (2,2) CASPT2) was also found to be adequate in describing the system and used to develop a novel force field. Our parametrization is able to predict the experimental CO 2 adsorption isotherms in HKUST-1, and it is shown to be transferable to other copper paddle-wheel systems.

Origin of the Strong Interaction between Polar Molecules and Copper(II) Paddle-Wheels in Metal Organic Frameworks

PubMed Central

2017-01-01

The copper paddle-wheel is the building unit of many metal organic frameworks. Because of the ability of the copper cations to attract polar molecules, copper paddle-wheels are promising for carbon dioxide adsorption and separation. They have therefore been studied extensively, both experimentally and computationally. In this work we investigate the copper–CO2 interaction in HKUST-1 and in two different cluster models of HKUST-1: monocopper Cu(formate)2 and dicopper Cu2(formate)4. We show that density functional theory methods severely underestimate the interaction energy between copper paddle-wheels and CO2, even including corrections for the dispersion forces. In contrast, a multireference wave function followed by perturbation theory to second order using the CASPT2 method correctly describes this interaction. The restricted open-shell Møller–Plesset 2 method (ROS-MP2, equivalent to (2,2) CASPT2) was also found to be adequate in describing the system and used to develop a novel force field. Our parametrization is able to predict the experimental CO2 adsorption isotherms in HKUST-1, and it is shown to be transferable to other copper paddle-wheel systems. PMID:28751926

Origin of the Strong Interaction between Polar Molecules and Copper(II) Paddle-Wheels in Metal Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ongari, Daniele; Tiana, Davide; Stoneburner, Samuel J.

The copper paddle-wheel is the building unit of many metal organic frameworks. Because of the ability of the copper cations to attract polar molecules, copper paddle-wheels are promising for carbon dioxide adsorption and separation. They have therefore been studied extensively, both experimentally and computationally. In this work we investigate the copper–CO 2 interaction in HKUST-1 and in two different cluster models of HKUST-1: monocopper Cu(formate) 2 and dicopper Cu 2(formate) 4. We show that density functional theory methods severely underestimate the interaction energy between copper paddle-wheels and CO 2, even including corrections for the dispersion forces. In contrast, a multireferencemore » wave function followed by perturbation theory to second order using the CASPT2 method correctly describes this interaction. The restricted open-shell Møller–Plesset 2 method (ROS-MP2, equivalent to (2,2) CASPT2) was also found to be adequate in describing the system and used to develop a novel force field. Our parametrization is able to predict the experimental CO 2 adsorption isotherms in HKUST-1, and it is shown to be transferable to other copper paddle-wheel systems.« less

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section... Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered for... marked on two sides “WARNING CO2 SOLID (DRY ICE).” (2) Other packagings containing solid carbon dioxide...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section... Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered for... marked on two sides “WARNING CO2 SOLID (DRY ICE).” (2) Other packagings containing solid carbon dioxide...

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section... Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered for... marked on two sides “WARNING CO2 SOLID (DRY ICE).” (2) Other packagings containing solid carbon dioxide...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section... Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered for... marked on two sides “WARNING CO2 SOLID (DRY ICE).” (2) Other packagings containing solid carbon dioxide...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section... Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered for... marked on two sides “WARNING CO2 SOLID (DRY ICE).” (2) Other packagings containing solid carbon dioxide...

Laboratory measurements of the 3.7-20 cm wavelength opacity of sulfur dioxide and carbon dioxide under simulated conditions for the deep atmosphere of Venus

NASA Astrophysics Data System (ADS)

Steffes, Paul G.; Shahan, Patrick; Christopher Barisich, G.; Bellotti, Amadeo

2015-01-01

In the past two decades, multiple observations of Venus have been made at X-Band (3.6 cm) using the Jansky Very Large Array (VLA), and maps have been created of the 3.6 cm emission from Venus (see, e.g., Devaraj, K. [2011]. The Centimeter- and Millimeter-Wavelength Ammonia Absorption Spectra under Jovian Conditions. PhD Thesis, Georgia Institute of Technology, Atlanta, GA). Since the emission morphology is related both to surface features and to deep atmospheric absorption from CO2 and SO2 (see, e.g., Butler, B.J., Steffes, P.G., Suleiman, S.H., Kolodner, M.A., Jenkins, J.M. [2001]. Icarus 154, 226-238), knowledge of the microwave absorption properties of sulfur dioxide in a carbon dioxide atmosphere under conditions for the deep atmosphere of Venus is required for proper interpretation. Except for a single measurement campaign conducted at a single wavelength (3.2 cm) over 40 years ago (Ho, W., Kaufman, I.A., Thaddeus, P. [1966]. J. Geophys. Res. 71, 5091-5108), no measurements of the centimeter-wavelength properties of any Venus atmospheric constituent have been conducted under conditions characteristic of the deep atmosphere (pressures from 10 to 92 bars and temperatures from 400 to 700 K). New measurements of the microwave properties of SO2 and CO2 at wavelengths from 3.7 to 20 cm have been conducted under simulated conditions for the deep atmosphere of Venus, using a new high-pressure system. Results from this measurement campaign conducted at temperatures from 430 K to 560 K and at pressures up to 92 bars are presented. Results indicate that the model for the centimeter-wavelength opacity from pure CO2 (Ho, W., Kaufman, I.A., Thaddeus, P. [1966]. J. Geophys. Res. 71, 5091-5108), is valid over the entire centimeter-wavelength range under simulated conditions for the deep atmosphere of Venus. Additionally, the laboratory results indicate that both of the models for the centimeter-wavelength opacity of SO2 in a CO2 atmosphere from Suleiman et al. (Suleiman, S.H., Kolodner, M.A., Steffes, P.G. [1996]. J. Geophys. Res. 101, 4623-4635) and from Fahd and Steffes (Fahd, A.K., Steffes, P.G. [1992]. Icarus 97, 200-210) can reliably be used under conditions of the deep atmosphere of Venus.

Nonthermal processing of orange juice using a pilot-plant scale supercritical carbon dioxide system with a gas-liquid metal contactor

USDA-ARS?s Scientific Manuscript database

To evaluate the effect of pilot-plant scale, non-thermal supercritical carbon dioxide (SCCO2) processing on the safety and the quality of orange juice (OJ), SCCO2 processed juice was compared with untreated fresh juice and equivalently thermal processed juice in terms of lethality. SCCO2 processing ...

A synthesis of the effects of atmospheric carbon dioxide enrichment on plant hydraulics: implications for whole-plant water use efficiency and resistance to drought.

PubMed

Domec, Jean-Christophe; Smith, Duncan D; McCulloh, Kate A

2017-06-01

Here, we summarize studies on the effects of elevated [CO 2 ] (CO 2 e ) on the structure and function of plant hydraulic architecture and explore the implications of those changes using a model. Changes in conduit diameter and hydraulic conductance due to CO 2 e vary among species. Ring-porous species tend towards an increase in conduit size and consequently conductivity. The effect in diffuse-porous species is much more limited. In conifers, the results are mixed, some species show minor changes in xylem structure, while other studies found increases in tracheid density and diameter. Non-woody plants generally exhibited the reverse pattern with narrower conduits and lower hydraulic conductivity under CO 2 e . Further, changes in drought-resistance traits suggest that non-woody plants were the most affected by CO 2 e , which may permit them to better resist drought-induced embolism under future conditions. Due to their complexity, acclimation in hydraulic traits in response to CO 2 e is difficult to interpret when relying solely on measurements. When we examined how the observed tissues-specific trends might alter plant function, our modelling results suggest that these hydraulic changes would lead to reduced conductance and more frequent drought stress in trees that develop under CO 2 e with a more pronounced effect in isohydric than in anisohydric species. © 2016 John Wiley & Sons Ltd.

Carbon dioxide diffusion across stomata and mesophyll and photo-biochemical processes as affected by growth CO2 and phosphorus nutrition in cotton

USDA-ARS?s Scientific Manuscript database

Nutrients such as phosphorus availability may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO2), which is projected to double by the end of 21st century. Elevated CO2 may overcome the diffusional limitation to photosynthesis posed by stomata and mesop...

Carbon Dioxide and Nitrogen Infused Compressed Air Foam for Depopulation of Caged Laying Hens

PubMed Central

Gurung, Shailesh; White, Dima; Archer, Gregory; Styles, Darrel; Zhao, Dan; Farnell, Yuhua; Byrd, James; Farnell, Morgan

2018-01-01

Simple Summary Compressed air, detergent, and water make up compressed air foam. Our laboratory has previously reported that compressed air foam may be an effective method for mass depopulation of caged layer hens. Gases, such as carbon dioxide and nitrogen, have also been used for poultry euthanasia and depopulation. The objective of this study was to produce compressed air foam infused with carbon dioxide or nitrogen to compare its efficacy against foam with air and gas inhalation methods (carbon dioxide or nitrogen) for depopulation of caged laying hens. The study showed that a carbon dioxide-air mixture or 100% nitrogen can replace air to make compressed air foam. However, the foam with carbon dioxide had poor foam quality compared to the foam with air or nitrogen. The physiological stress response of hens subjected to foam treatments with and without gas infusion did not differ significantly. Hens exposed to foam with nitrogen died earlier as compared to methods such as foam with air and carbon dioxide. The authors conclude that infusion of nitrogen into compressed air foam results in better foam quality and shortened time to death as compared to the addition of carbon dioxide. Abstract Depopulation of infected poultry flocks is a key strategy to control and contain reportable diseases. Water-based foam, carbon dioxide inhalation, and ventilation shutdown are depopulation methods available to the poultry industry. Unfortunately, these methods have limited usage in caged layer hen operations. Personnel safety and welfare of birds are equally important factors to consider during emergency depopulation procedures. We have previously reported that compressed air foam (CAF) is an alternative method for depopulation of caged layer hens. We hypothesized that infusion of gases, such as carbon dioxide (CO2) and nitrogen (N2), into the CAF would reduce physiological stress and shorten time to cessation of movement. The study had six treatments, namely a negative control, CO2 inhalation, N2 inhalation, CAF with air (CAF Air), CAF with 50% CO2 (CAF CO2), and CAF with 100% N2 (CAF N2). Four spent hens were randomly assigned to one of these treatments on each of the eight replication days. A total of 192 spent hens were used in this study. Serum corticosterone and serotonin levels were measured and compared between treatments. Time to cessation of movement of spent hens was determined using accelerometers. The addition of CO2 in CAF significantly reduced the foam quality while the addition of N2 did not. The corticosterone and serotonin levels of spent hens subjected to foam (CAF, CAF CO2, CAF N2) and gas inhalation (CO2, N2) treatments did not differ significantly. The time to cessation of movement of spent hens in the CAF N2 treatment was significantly shorter than CAF and CAF CO2 treatments but longer than the gas inhalation treatments. These data suggest that the addition of N2 is advantageous in terms of shortening time to death and improved foam quality as compared to the CAF CO2 treatment. PMID:29301340

Electrocatalytic process for carbon dioxide conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masel, Richard I.; Salehi-Khojin, Amin; Kutz, Robert

An electrocatalytic process for carbon dioxide conversion includes combining a Catalytically Active Element and a Helper Polymer in the presence of carbon dioxide, allowing a reaction to proceed to produce a reaction product, and applying electrical energy to said reaction to achieve electrochemical conversion of said carbon dioxide reactant to said reaction product. The Catalytically Active Element can be a metal in the form of supported or unsupported particles or flakes with an average size between 0.6 nm and 100 nm. The reaction products comprise at least one of CO, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH,more » C.sub.2H.sub.6, (COOH).sub.2, (COO.sup.-).sub.2, and CF.sub.3COOH.« less

Recuperative supercritical carbon dioxide cycle

DOEpatents

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

2014-11-18

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.

Validation of double-pulse 1572 nm integrated path differential absorption lidar measurement of carbon dioxide

NASA Astrophysics Data System (ADS)

Du, Juan; Liu, Jiqiao; Bi, Decang; Ma, Xiuhua; Hou, Xia; Zhu, Xiaolei; Chen, Weibiao

2018-04-01

A ground-based double-pulse 1572 nm integrated path differential absorption (IPDA) lidar was developed for carbon dioxide (CO2) column concentrations measurement. The lidar measured the CO2 concentrations continuously by receiving the scattered echo signal from a building about 1300 m away. The other two instruments of TDLAS and in-situ CO2 analyzer measured the CO2 concentrations on the same time. A CO2 concentration measurement of 430 ppm with 1.637 ppm standard error was achieved.

Sterilizing Bacillus pumilus spores using supercritical carbon dioxide.

PubMed

Zhang, Jian; Burrows, Sarah; Gleason, Courtney; Matthews, Michael A; Drews, Michael J; Laberge, Martine; An, Yuehuei H

2006-09-01

Supercritical carbon dioxide (SC CO(2)) has been evaluated as a new sterilization technology. Results are presented on killing of B. pumilus spores using SC CO(2) containing trace levels of additives. Complete killing was achieved with 200 part per million (ppm) hydrogen peroxide in SC CO(2) at 60 degrees C, 27.5 MPa. Addition of water to SC CO(2) resulted in greater than three-log killing, but this is insufficient to claim sterilization. Neither ethanol nor isopropanol when added to SC CO(2) affected killing.

Application of water-insoluble polymers to orally disintegrating tablets treated by high-pressure carbon dioxide gas.

PubMed

Ito, Yoshitaka; Maeda, Atsushi; Kondo, Hiromu; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

2016-09-10

The phase transition of pharmaceutical excipients that can be induced by humidifying or heating is well-known to increase the hardness of orally disintegrating tablets (ODTs). However, these conditions are not applicable to drug substances that are chemically unstable against such stressors. Here, we describe a system which enhances the hardness of tablets containing water-insoluble polymers by using high-pressure carbon dioxide (CO2). On screening of 26 polymeric excipients, aminoalkyl methacrylate copolymer E (AMCE) markedly increased tablet hardness (+155N) when maintained in a high-pressure CO2 environment. ODTs containing 10% AMCE were prepared and treatment with 4.0MPa CO2 gas at 25°C for 10min increased the hardness to +30N, whose level corresponded to heating at 70°C for 720min. In addition, we confirmed the effects of CO2 pressure, temperature, treatment time, and AMCE content on the physical properties of ODTs. Optimal pressure of CO2 gas was considered to be approximately 3.5MPa for an AMCE formula, as excessive pressure delayed the disintegration of ODTs. Combination of high-pressure CO2 gas and AMCE is a prospective approach for increasing the tablet hardness for ODTs, and can be conducted without additional heat or moisture stress using a simple apparatus. Copyright © 2016 Elsevier B.V. All rights reserved.

Global Biogenic Emission of Carbon Dioxide from Landfills

NASA Astrophysics Data System (ADS)

Lima, R.; Nolasco, D.; Meneses, W.; Salazar, J.; Hernández, P.; Pérez, N.

2002-12-01

Human-induced increases in the atmospheric concentrations of greenhouse gas components have been underway over the past century and are expected to drive climate change in the coming decades. Carbon dioxide was responsible for an estimated 55 % of the antropogenically driven radiactive forcing of the atmosphere in the 1980s and is predicted to have even greater importance over the next century (Houghton et al., 1990). A highly resolved understanding of the sources and sinks of atmospheric CO2, and how they are affected by climate and land use, is essential in the analysis of the global carbon cycle and how it may be impacted by human activities. Landfills are biochemical reactors that produce CH4 and CO2 emissions due to anaerobic digestion of solid urban wastes. Estimated global CH4 emission from landfills is about 44 millions tons per year and account for a 7.4 % of all CH4 sources (Whiticar, 1989). Observed CO2/CH4 molar ratios from landfill gases lie within the range of 0.7-1.0; therefore, an estimated global biogenic emission of CO2 from landfills could reach levels of 11.2-16 millions tons per year. Since biogas extraction systems are installed for extracting, purifying and burning the landfill gases, most of the biogenic gas emission to the atmosphere from landfills occurs through the surface environment in a diffuse and disperse form, also known as non-controlled biogenic emission. Several studies of non-controlled biogenic gas emission from landfills showed that CO2/CH4 weight ratios of surface landfill gases, which are directly injected into the atmosphere, are about 200-300 times higher than those observed in the landfill wells, which are usually collected and burned by gas extraction systems. This difference between surface and well landfill gases is mainly due to bacterial oxidation of the CH4 to CO2 inducing higher CO2/CH4 ratios for surface landfill gases than those well landfill gases. Taking into consideration this observation, the global biogenic CO2 emission from landfills could be estimated about 8.8-13.2\\times103 million tons per year, equivalent to a 0.04-0.06 % of the fossil fuel emission of CO2.

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

PubMed Central

Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

2015-01-01

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review. PMID:26690155

Method for carbon dioxide sequestration

DOEpatents

Wang, Yifeng; Bryan, Charles R.; Dewers, Thomas; Heath, Jason E.

2015-09-22

A method for geo-sequestration of a carbon dioxide includes selection of a target water-laden geological formation with low-permeability interbeds, providing an injection well into the formation and injecting supercritical carbon dioxide (SC--CO.sub.2) into the injection well under conditions of temperature, pressure and density selected to cause the fluid to enter the formation and splinter and/or form immobilized ganglia within the formation. This process allows for the immobilization of the injected SC--CO.sub.2 for very long times. The dispersal of scCO2 into small ganglia is accomplished by alternating injection of SC--CO.sub.2 and water. The injection rate is required to be high enough to ensure the SC--CO.sub.2 at the advancing front to be broken into pieces and small enough for immobilization through viscous instability.

Performance of Charcoal Cookstoves for Haiti, Part 2: Results from the Controlled Cooking Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lask, Kathleen; Jones, Jennifer; Booker, Kayje

2011-11-30

Five charcoal cookstoves were tested using a Controlled Cooking Test (CCT) developed from cooking practices in Haiti. Cookstoves were tested for total burn time, specific fuel consumption, and emissions of carbon monoxide (CO), carbon dioxide (CO 2), and the ratio of carbon monoxide to carbon dioxide (CO/CO 2). These results are presented in this report along with LBNL testers’ observations regarding the usability of the stoves.

Six-man, self-contained carbon dioxide concentrator system

NASA Technical Reports Server (NTRS)

Powell, J. D.; Schubert, F. H.; Marshall, R. D.; Shumar, J. W.

1974-01-01

A six man, self contained electrochemical carbon dioxide concentrating subsystem was successfully designed and fabricated. It was a preprototype engineering model designed to nominally remove 6.0 kg (13.2 lb) CO2/day with an inlet air CO2 partial pressure of 400 N/sq m (3 mm Hg) and an overcapacity removal capability of 12.0 kg (26.4 lb) CO2/day. The design specifications were later expanded to allow operation at space station prototype CO2 collection subsystem operating conditions.

Experimental research on the effects of water application on greenhouse gas emissions from beef cattle feedlots

USDA-ARS?s Scientific Manuscript database

The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/ma...

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

USGS Publications Warehouse

Colt, John; Watten, Barnaby; Pfeiffer, Tim

2012-01-01

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 μeq/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.

Ongoing Development of a Series Bosch Reactor System

NASA Technical Reports Server (NTRS)

Abney, Morgan; Mansell, Matt; DuMez, Sam; Thomas, John; Cooper, Charlie; Long, David

2013-01-01

Future manned missions to deep space or planetary surfaces will undoubtedly require highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch-based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water-Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian and Lunar regolith simulant for the carbon deposition step.

Application of Signal Analysis to the Climate

PubMed Central

2014-01-01

The primary ingredient of the Anthropogenic Global Warming hypothesis, namely, the assumption that additional atmospheric carbon dioxide substantially raises the global temperature, is studied. This is done by looking at the data of temperature and CO2, both in the time domain and in the phase domain of periodic data. Bicentenary measurements are analyzed and a relaxation model is introduced in the form of an electronic equivalent circuit. The effects of this relaxation manifest themselves in delays in the time domain and correlated phase shifts in the phase domain. For extremely long relaxation time constants, the delay is maximally one-quarter period, which for the yearly-periodic signal means 3 months. This is not in line with the analyzed data, the latter showing delays of 9 (−3) months. These results indicate a reverse function of cause and effect, with temperature being the cause for atmospheric CO2 changes, rather than their effect. These two hypotheses are discussed on basis of literature, where it was also reported that CO2 variations are lagging behind temperature variations. PMID:27350978

Ongoing Development of a Series Bosch Reactor System

NASA Technical Reports Server (NTRS)

Abney, Morgan B; Mansell, J. Matthew; Stanley, Christine; Edmunson, Jennifer; DuMez, Samuel J.; Chen, Kevin

2013-01-01

Future manned missions to deep space or planetary surfaces will undoubtedly incorporate highly robust, efficient, and regenerable life support systems that require minimal consumables. To meet this requirement, NASA continues to explore a Bosch-based carbon dioxide reduction system to recover oxygen from CO2. In order to improve the equivalent system mass of Bosch systems, we seek to design and test a "Series Bosch" system in which two reactors in series are optimized for the two steps of the reaction, as well as to explore the use of in situ materials as carbon deposition catalysts. Here we report recent developments in this effort including assembly and initial testing of a Reverse Water-Gas Shift reactor (RWGSr) and initial testing of two gas separation membranes. The RWGSr was sized to reduce CO2 produced by a crew of four to carbon monoxide as the first stage in a Series Bosch system. The gas separation membranes, necessary to recycle unreacted hydrogen and CO2, were similarly sized. Additionally, we report results of preliminary experiments designed to determine the catalytic properties of Martian regolith simulant for the carbon formation step.

Nucleation of Super-Critical Carbon Dioxide in a Venturi Nozzle

NASA Astrophysics Data System (ADS)

Jarrahbashi, Dorrin; Pidaparti, Sandeep; Ranjan, Devesh

2015-11-01

The supercritical carbon dioxide (S-CO2) Brayton cycle combines the primary advantages of the ideal Brayton and Rankine cycles by utilizing CO2 above its critical pressure. In addition to single phase and small back work ratios, supercritical fluids offer other advantages, e.g. heat transfer augmentation and low specific volume. Pressure reduction at the entrance of the compressor may cause homogenous nucleation, vapor production, and collapse of bubbles due to operation near the saturation conditions. Transient behavior of the flow after nucleation may cause serious issues in operation of the cycle and affect the materials used in design. The flow of S-CO2 through a venturi nozzle near the critical point has been studied. A transient compressible 3D Navier-Stokes solver, coupled with continuity, and energy equation has been used. Developed FIT libraries based on a piecewise biquintic spline interpolation of Helmholtz energy have been integrated with OpenFOAM to model S-CO2 properties. The mass fraction of vapor created in the venturi has been calculated using homogeneous equilibrium model (HEM). The flow conditions that lead to nucleation have been investigated. The sensitivity of nucleation to the inlet pressure and temperature, flow rate, and venturi profile has been shown.

Determination of the equation parameters of carbon flow curves and estimated carbon flow and CO2 emissions from broiler production.

PubMed

Henn, J D; Bockor, L; Borille, R; Coldebella, A; Ribeiro, A M L; Kessler, A M

2015-09-01

The objective of this study was to determine the equation parameters of carbon (i.e., C) flow curves and to estimate C flow and carbon dioxide (i.e., CO2) emissions from the production of 1- to 49-day-old broilers from different genetic strains. In total, 384 1-day-old chicks were used, distributed into 4 groups: high-performance males (Cobb-M) and females (Cobb-F), and intermediate-performance males (C44-M) and females (C44-F), with 6 replicates/treatment according to a completely randomized study design. Carbon intake and retention were calculated based on diet and body C composition, and expired C was stoichiometrically estimated as digestible C intake-C retention-C in the urine. Litter C emission was estimated as initial litter C+C in the excreta-final litter C. Carbon flow curves were determined fitting data by nonlinear regression using the Gompertz function. Expired CO2 was calculated based on expired C. The applied nonlinear model presented goodness-of-fit for all responses (R2>0.99). Carbon dioxide production was highly correlated with growth rate. At 42 d age, CO2 expiration (g/bird) was 3,384.4 for Cobb-M, 2,947.9 for Cobb-F, 2,512.5 for C44-M, and 2185.1 for C44-F. Age also significantly affected CO2 production: to achieve 2.0 kg BW, CO2 expiration (g/bird) was 1,794.3 for Cobb-M, 2,016.5 for Cobb-F, 2617.7 for C44-M, and 3,092.3 for C44-F. The obtained equations present high predictability to estimate individual CO2 emissions in strains of Cobb and C44 broilers of any weight, or age, reared between 1 and 49 d age. © 2015 Poultry Science Association Inc.

Global temperature change potential of nitrogen use in agriculture: A 50-year assessment

PubMed Central

Fagodiya, R. K.; Pathak, H.; Kumar, A.; Bhatia, A.; Jain, N.

2017-01-01

Nitrogen (N) use in agriculture substantially alters global N cycle with the short- and long-term effects on global warming and climate change. It increases emission of nitrous oxide, which contributes 6.2%, while carbon dioxide and methane contribute 76% and 16%, respectively of the global warming. However, N causes cooling due to emission of NOx, which alters concentrations of tropospheric ozone and methane. NOx and NH3 also form aerosols with considerable cooling effects. We studied global temperature change potential (GTP) of N use in agriculture. The GTP due to N2O was 396.67 and 1168.32 Tg CO2e on a 20-year (GTP20) and 439.94 and 1295.78 Tg CO2e on 100-year scale (GTP100) during years 1961 and 2010, respectively. Cooling effects due to N use were 92.14 and 271.39 Tg CO2e (GTP20) and 15.21 and 44.80 Tg CO2e (GTP100) during 1961 and 2010, respectively. Net GTP20 was 369.44 and 1088.15 Tg CO2e and net GTP100 was 429.17 and 1264.06 Tg CO2e during 1961 and 2010, respectively. Thus net GTP20 is lower by 6.9% and GTP100 by 2.4% compared to the GTP considering N2O emission alone. The study shows that both warming and cooling effects should be considered to estimate the GTP of N use. PMID:28322322

Carbon Disulfide (CS2) Mechanisms in Formation of Atmospheric Carbon Dioxide (CO2) Formation from Unconventional Shale Gas Extraction and Processing Operations and Global Climate Change.

PubMed

Rich, Alisa L; Patel, Jay T

2015-01-01

Carbon disulfide (CS2) has been historically associated with the production of rayon, cellophane, and carbon tetrachloride. This study identifies multiple mechanisms by which CS2 contributes to the formation of CO2 in the atmosphere. CS2 and other associated sulfide compounds were found by this study to be present in emissions from unconventional shale gas extraction and processing (E&P) operations. The breakdown products of CS2; carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) are indirect greenhouse gases (GHGs) that contribute to CO2 levels in the atmosphere. The heat-trapping nature of CO2 has been found to increase the surface temperature, resulting in regional and global climate change. The purpose of this study is to identify five mechanisms by which CS2 and the breakdown products of CS2 contribute to atmospheric concentrations of CO2. The five mechanisms of CO2 formation are as follows: Chemical Interaction of CS2 and hydrogen sulfide (H2S) present in natural gas at high temperatures, resulting in CO2 formation;Combustion of CS2 in the presence of oxygen producing SO2 and CO2;Photolysis of CS2 leading to the formation of COS, CO, and SO2, which are indirect contributors to CO2 formation;One-step hydrolysis of CS2, producing reactive intermediates and ultimately forming H2S and CO2;Two-step hydrolysis of CS2 forming the reactive COS intermediate that reacts with an additional water molecule, ultimately forming H2S and CO2. CS2 and COS additionally are implicated in the formation of SO2 in the stratosphere and/or troposphere. SO2 is an indirect contributor to CO2 formation and is implicated in global climate change.

Development of a low cost unmanned aircraft system for atmospheric carbon dioxide leak detection

NASA Astrophysics Data System (ADS)

Mitchell, Taylor Austin

Carbon sequestration, the storage of carbon dioxide gas underground, has the potential to reduce global warming by removing a greenhouse gas from the atmosphere. These storage sites, however, must first be monitored to detect if carbon dioxide is leaking back out to the atmosphere. As an alternative to traditional large ground-based sensor networks to monitor CO2 levels for leaks, unmanned aircraft offer the potential to perform in-situ atmospheric leak detection over large areas for a fraction of the cost. This project developed a proof-of-concept sensor system to map relative carbon dioxide levels to detect potential leaks. The sensor system included a Sensair K-30 FR CO2 sensor, GPS, and altimeter connected an Arduino microcontroller which logged data to an onboard SD card. Ground tests were performed to verify and calibrate the system including wind tunnel tests to determine the optimal configuration of the system for the quickest response time (4-8 seconds based upon flowrate). Tests were then conducted over a controlled release of CO 2 in addition to over controlled rangeland fires which released carbon dioxide over a large area as would be expected from a carbon sequestration source. 3D maps of carbon dioxide were developed from the system telemetry that clearly illustrated increased CO2 levels from the fires. These tests demonstrated the system's ability to detect increased carbon dioxide concentrations in the atmosphere.

Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling

NASA Astrophysics Data System (ADS)

Schmidt, Andres; Rella, Chris W.; Göckede, Mathias; Hanson, Chad; Yang, Zhenlin; Law, Beverly E.

2014-11-01

In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring-Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO/CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (±1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values ranging from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

Elevated CO2 induces a global metabolic change in basil (Ocimum basilicum L.) and peppermint (Mentha piperita L.) and improves their biological activity.

PubMed

Al Jaouni, Soad; Saleh, Ahmed M; Wadaan, Mohammed A M; Hozzein, Wael N; Selim, Samy; AbdElgawad, Hamada

Many studies have discussed the influence of elevated carbon dioxide (eCO 2 ) on modeling and crop plants. However, much less effort has been dedicated to herbal plants. In this study, a robust monitoring for the levels of 94 primary and secondary metabolites and minerals in two medicinal herbs, basil (Ocimum basilicum L.) and peppermint (Mentha piperita L.), grwon under both ambient (aCO 2 , 360 ppm) and eCO 2 (620 ppm) was performed. We also assessed how the changes in herbal tissue chemistry affected their biological activity. Elevated CO 2 significantly increased herbal biomass, improved the rates of photosynthesis and dark respiration, and altered the tissue chemistry. Principal Component Analysis of the full data set revealed that eCO 2 induced a global change in the metabolomes of the two plants. Moreover, Hierarchical Clustering Analyses showed quantitative differences in the metabolic profiles of the two plants and in their responsiveness to eCO 2 . Out of 94 metabolites, 38 and 31 significantly increased in basil and peppermint, respectively, as affected by eCO 2 . Regardless of the plant species, the levels of non-structural carbohydrates, fumarate, glutamine, glutathione, ascorbate, phylloquinone (vitamin K1), anthocyanins and a majority of flavonoids and minerals were significantly improved by eCO 2 . However, some metabolites tended to show species specificity. Interestingly, eCO 2 caused enhancement in antioxidant, antiprotozoal, anti-bacterial and anticancer (against urinary bladder carcinoma; T24P) activities in both plants, which was consequent with improvement in the levels of antioxidant metabolites such as glutathione, ascorbate and flavonoids. Therefore, this study suggests that the metabolic changes triggered by eCO 2 in the target herbal plants improved their biological activities. Copyright © 2018 Elsevier GmbH. All rights reserved.

Determination of the effect of different atmospheric composition on the quality of cold stored irradiated apples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okamoto, T.; Harata, J.; Osanai, T.

1972-03-01

Jonathan apples were irradiated with /sup 60/Co gamma rays, in doses of 0 (control), 2.5, 5, 7.5, 10, 50, 100 krad (dose rate: 20 krad/hr), and 50krad (dose rate: 100 krad/hr), and stored at 0 deg C in three controlled atmosphere rooms (oxygen 3 to 5%, carbon dioxide below 0.5%; oxygen 21%, carbon dioxide 2 to 2.5%; oxygen 3 to 5%, carbon dioxide 2 to 2.5%) and in a common refrigerated room for 4.5 months. Irradiation of apples with doses of 10 krsd or more seemed to lower slightly their qualities and the same tendency was obseved in CA apples.more » Generally, the effects of CA storage, especially in 3 to 5% O/sub 2/ and 2 to 2.5% CO/sub 2/, on the qualities of apples, i.e., respiration, organoleptic properties, changes in weight, surface color, were stronger than the irradiation effect. However, it seems to be true that the treatment with doses of about 5 krad is not at all inferior to the other treatment. So, as the pretreatment of CA storage of apples the irradiation dose of about 5 krad may be recommended. (auth)« less

An in vitro evaluation of the antibacterial efficacy of chlorine dioxide on E. faecalis in bovine incisors.

PubMed

Eddy, Russell S; Joyce, Anthony P; Roberts, Steven; Buxton, Thomas B; Liewehr, Frederick

2005-09-01

This study investigated the ability of chlorine dioxide to eliminate Enterococcus faecalis from dentinal tubules of bovine incisors. Thirty-seven extracted bovine incisor roots were sectioned into seventy-four 5 mm disks. Standardized lumens were filled with either sterile Brain Heart Infusion Broth (contamination controls, n = 10) or BHI containing E. faecalis (1.0 x 10 cfu/ml). Disks were incubated in 5% CO2 at 37 degrees C for 72 h. To simulate endodontic instrumentation the lumens were again enlarged. Sixty disks were randomly divided into four experimental groups and filled with one of the following irrigants: 10% Clidox-S (chlorine dioxide), 13.8% BioClenz (chlorine dioxide), 5.25% Clorox, or saline. The disks were incubated for 30 min and were then frozen, pulverized, serially diluted in phosphate buffered saline, and plated on BHI plates in triplicate. Total colony forming units were counted macroscopically. Statistical analysis of the data was performed with a Kruskal-Wallis one-way ANOVA on ranks (p < 0.05, n = 60). Bacterial counts, expressed in log10 cfu/disk were as follows (">" denotes significant differences): Saline > Clidox-S = BioClenz > Clorox. All negative controls were sterile. Chlorine dioxide and NaOCL were both effective in eliminating E. faecalis from the dentinal disks within 30 min.

Alternations of Structure and Functional Activity of Below Ground Microbial Communities at Elevated Atmospheric Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Zhili; Xu, Meiying; Deng, Ye

2010-05-17

The global atmospheric concentration of CO2 has increased by more than 30percent since the industrial revolution. Although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity have been well studied, its influences on belowground microbial communities are poorly understood and controversial. In this study, we showed a significant change in the structure and functional potential of soil microbial communities at eCO2 in a grassland ecosystem, the BioCON (Biodiversity, CO2 and Nitrogen) experimental site (http://www.biocon.umn.edu/) using a comprehensive functional gene array, GeoChip 3.0, which contains about 28,0000 probes and covers approximately 57,000 gene variants from 292 functionalmore » gene families involved in carbon, nitrogen, phosphorus and sulfur cycles as well as other functional processes. GeoChip data indicated that the functional structure of microbial communities was markedly different between ambient CO2 (aCO2) and eCO2 by detrended correspondence analysis (DCA) of all 5001 detected functional gene probes although no significant differences were detected in the overall microbial diversity. A further analysis of 1503 detected functional genes involved in C, N, P, and S cycles showed that a considerable portion (39percent) of them were only detected under either aCO2 (14percent) or eCO2 (25percent), indicating that the functional characteristics of the microbial community were significantly altered by eCO2. Also, for those shared genes (61percent) detected, some significantly (p<0.05) changed their abundance at eCO2. Especially, genes involved in labile C degradation, such as amyA, egl, and ara for starch, cellulose, and hemicelluloses, respectively, C fixation (e.g., rbcL, pcc/acc), N fixation (nifH), and phosphorus utilization (ppx) were significantly increased under eCO2, while those involved in decomposing recalcitrant C, such as glx, lip, and mnp for lignin degradation remained unchanged. This study provides insights into our understanding of belowground microbial communities and their feedbacks to terrestrial ecosystems at eCO2.« less

Determination of exhaled nitric oxide distributions in a diverse sample population using tunable diode laser absorption spectroscopy

NASA Astrophysics Data System (ADS)

Namjou, K.; Roller, C. B.; Reich, T. E.; Jeffers, J. D.; McMillen, G. L.; McCann, P. J.; Camp, M. A.

2006-11-01

A liquid-nitrogen free mid-infrared tunable diode laser absorption spectroscopy (TDLAS) system equipped with a folded-optical-path astigmatic Herriott cell was used to measure levels of exhaled nitric oxide (eNO) and exhaled carbon dioxide (eCO2) in breath. Quantification of absolute eNO concentrations was performed using NO/CO2 absorption ratios measured by the TDLAS system coupled with absolute eCO2 concentrations measured with a non-dispersive infrared sensor. This technique eliminated the need for routine calibrations using standard cylinder gases. The TDLAS system was used to measure eNO in children and adults (n=799, ages 5 to 64) over a period of more than one year as part of a field study. Volunteers for the study self-reported data including age, height, weight, and health status. The resulting data were used to assess system performance and to generate eNO and eCO2 distributions, which were found to be log-normal and Gaussian, respectively. There were statistically significant differences in mean eNO levels for males and females as well as for healthy and steroid naïve asthmatic volunteers not taking corticosteroid therapies. Ambient NO levels affected measured eNO concentrations only slightly, but this effect was not statistically significant.

Removal of sulfur dioxide and formation of sulfate aerosol in Tokyo

NASA Astrophysics Data System (ADS)

Miyakawa, T.; Takegawa, N.; Kondo, Y.

2007-07-01

Ground-based in situ measurements of sulfur dioxide (SO2) and submicron sulfate aerosol (SO42-) together with carbon monoxide (CO) were conducted at an urban site in Tokyo, Japan from spring 2003 to winter 2004. The observed concentrations of SO2 were affected dominantly by anthropogenic emissions (for example, manufacturing industries) in source areas, while small fraction of the data (<30%) was affected by large point sources of SO2 (power plant and volcano). Although emission sources of CO in Tokyo are different from those of SO2, the major emission sources of CO and SO2 are colocated, indicating that CO can be used as a tracer of anthropogenic SO2 emissions in Tokyo. The ratio of SO42- to total sulfur compounds (SOx = SO2 + SO42-) and the remaining fraction of SOx, which is derived as the ratio of the linear regression slope of the SOx-CO correlation, is used as measures for the formation of SO42- and removal of SOx, respectively. Using these parameters, the average formation efficiency of SO42- (i.e., amount of SO42- produced per SO2 emitted from emission sources) are estimated to be 0.18 and 0.03 in the summer and winter periods, respectively. A simple box model was developed to estimate the lifetime of SOx. The lifetime of SOx for the summer period (26 h) is estimated to be about two times longer than that for the winter period (14 h). The seasonal variations of the remaining fraction of SOx, estimated formation efficiency of SO42-, and lifetime of SOx are likely due to those of the boundary layer height and photochemical activity (i.e., hydroxyl radical). These results provide useful insights into the formation and removal processes of sulfur compounds exported from an urban area.

Conversion of carbon dioxide to carbon monoxide by pulse dielectric barrier discharge plasma

NASA Astrophysics Data System (ADS)

Wang, Taobo; Liu, Hongxia; Xiong, Xiang; Feng, Xinxin

2017-01-01

The conversion of carbon dioxide (CO2) to carbon monoxide (CO) was investigated in a non-thermal plasma dielectric barrier discharge (DBD) reactor, and the effects of different process conditions on the CO2 conversion were investigated. The results showed that the increase of input power could optimize the conversion of CO2 to CO. The CO2 conversion and CO yield were negatively correlated with the gas flow rate, but there was an optimum gas flow rate, that made the CO selectivity best. The carrier gas (N2, Ar) was conducive to the conversion of CO2, and the effect of N2 as carrier gas was better than Ar. The conversion of CO2 to CO was enhanced by addition of the catalyst (5A molecular sieve).

Revealing the Origin of Activity in Nitrogen-Doped Nanocarbons towards Electrocatalytic Reduction of Carbon Dioxide.

PubMed

Xu, Junyuan; Kan, Yuhe; Huang, Rui; Zhang, Bingsen; Wang, Bolun; Wu, Kuang-Hsu; Lin, Yangming; Sun, Xiaoyan; Li, Qingfeng; Centi, Gabriele; Su, Dangsheng

2016-05-23

Carbon nanotubes (CNTs) are functionalized with nitrogen atoms for reduction of carbon dioxide (CO2 ). The investigation explores the origin of the catalyst's activity and the role of nitrogen chemical states therein. The catalysts show excellent performances, with about 90 % current efficiency for CO formation and stability over 60 hours. The Tafel analyses and density functional theory calculations suggest that the reduction of CO2 proceeds through an initial rate-determining transfer of one electron to CO2 , which leads to the formation of carbon dioxide radical anion (CO2 (.-) ). The initial reduction barrier is too high on pristine CNTs, resulting in a very high overpotentials at which the hydrogen evolution reaction dominates over CO2 reduction. The doped nitrogen atoms stabilize the radical anion, thereby lowering the initial reduction barrier and improving the intrinsic activity. The most efficient nitrogen chemical state for this reaction is quaternary nitrogen, followed by pyridinic and pyrrolic nitrogen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple method for isocapnic hyperventilation evaluated in a lung model.

PubMed

Hallén, K; Stenqvist, O; Ricksten, S-E; Lindgren, S

2016-05-01

Isocapnic hyperventilation (IHV) has the potential to increase the elimination rate of anaesthetic gases and has been shown to shorten time to wake-up and post-operative recovery time after inhalation anaesthesia. In this bench test, we describe a technique to achieve isocapnia during hyperventilation (HV) by adding carbon dioxide (CO2) directly to the breathing circuit of a standard anaesthesia apparatus with standard monitoring equipment. Into a mechanical lung model, carbon dioxide was added to simulate a CO2 production (V(CO2)) of 175, 200 and 225 ml/min. Dead space (V(D)) volume could be set at 44, 92 and 134 ml. From baseline ventilation (BLV), HV was achieved by doubling the minute ventilation and fresh gas flow for each level of V(CO2), and dead space. During HV, CO2 was delivered (D(CO2)) by a precision flow meter via a mixing box to the inspiratory limb of the anaesthesia circuit to achieve isocapnia. During HV, the alveolar ventilation increased by 113 ± 6%. Tidal volume increased by 20 ± 0.1% during IHV irrespective of V(D) and V(CO2) level. D(CO2) varied between 147 ± 8 and 325 ± 13 ml/min. Low V(CO2) and large V(D) demanded a greater D(CO2) administration to achieve isocapnia. The FICO2 level during IHV varied between 2.3% and 3.3%. It is possible to maintain isocapnia during HV by delivering carbon dioxide through a standard anaesthesia circuit equipped with modern monitoring capacities. From alveolar ventilation, CO2 production and dead space, the amount of carbon dioxide that is needed to achieve IHV can be estimated. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Photoexcitation and ionization in carbon dioxide - Theoretical studies in the separated-channel static-exchange approximation

NASA Technical Reports Server (NTRS)

Padial, N.; Csanak, G.; Mckoy, B. V.; Langhoff, P. W.

1981-01-01

Vertical-electronic static-exchange photoexcitation and ionization cross sections are reported which provide a first approximation to the complete dipole spectrum of CO2. Separated-channel static-exchange calculations of vertical-electronic transition energies and oscillator strengths, and Stieltjes-Chebyshev moment methods were used in the development. Detailed comparisons were made of the static-exchange excitation and ionization spectra with photoabsorption, electron-impact excitation, and quantum-defect estimates of discrete transition energies and intensities, and with partial-channel photoionization cross sections obtained from fluorescence measurements and from tunable-source and (e, 2e) photoelectron spectroscopy. Results show that the separate-channel static-exchange approximation is generally satisfactory in CO2.

Shipboard monitoring of non-CO2 greenhouse gases in Asia and Oceania using commercially cargo vessels

NASA Astrophysics Data System (ADS)

Nara, H.; Tanimoto, H.; Mukai, H.; Nojiri, Y.; Tohjima, Y.; Machida, T.; Hashimoto, S.

2011-12-01

The National Institute for Environmental Studies (NIES) has been performing a long-term program for monitoring trace gases of atmospheric importance over the Pacific Ocean since 1995. The NIES Voluntary Observing Ships (NIES-VOS) program currently makes use of commercial cargo vessels because they operate regularly over fixed routes for long periods and sail over a wide area between various ports (e.g., between Japan and the United States, between Japan and Australia/New Zealand, and between Japan and southeast Asia). This program allows systematic and continuous measurements of non-CO2 greenhouse gases, providing long-term datasets for background air over the Pacific Ocean and regionally polluted air around east Asia. We observe both long-lived greenhouse gases (e.g., carbon dioxide) and short-lived air pollutants (e.g., tropospheric ozone, carbon monoxide) on a continuous basis. Flask samples are collected for later laboratory analysis of carbon dioxide, methane, nitrous oxide, and carbon monoxide by using gas chromatographic techniques. In addition, we recently installed cavity ringdown spectrometers for high-resolution measurement of methane and carbon dioxide to capture their highly variable features in regionally polluted air around southeast Asia (e.g., Hong Kong, Thailand, Singapore, Malaysia, Indonesia and Philippine), which is now thought to be a large source due to expanding socioeconomic activities as well as biomass burnings. Contrasting the Japan-Australia/New Zealand and Japan-southeast Asia cruises revealed regional characteristics of sources and sinks of these atmospherically important species, suggesting the existence of additional sources for methane, nitrous oxides, and carbon monoxide in this tropical Asian region.

Contribution to Conversion of CO2 to fuel by electro-photo-catalytic reduction in hydro-genocarbonated aqueous solution tion

NASA Astrophysics Data System (ADS)

Nezzal, Ghania; Benammar, Souad; Hamouni, Samia; Meziane, Dalila; Naama, Sabrina; Abdessemed, Djamel

2015-04-01

Referring to the last World Conference COPENHAGEN (2010), endorsed by the United Nations,to '' RISKS OF CLIMATE CHANGES ', states had not reached an agreement to work fairly, in an international program, to limit Carbon dioxide emissions into the atmosphere, to put off it, to the next (in 2015), the right decisions, despite the recommendations of the 'IPCC'. Based on the natural reaction of photosynthesis, which converts carbon dioxide in the presence of water and sun, to '' OSA'' ', it is natural that scientists believe to implement an artificial conversion of CO2 in a renewable energy faster. Our contribution focuses on the same goals, by a different line. In this perspective, nano-materials, catalysts, pervaporation membranes, pervaporation unit, and a photo-reactor prototype, have been made. A summary of the preliminary results presented: For example, are given the concentrations of the various species present in a aqueous solution of sodium hydrogen carbonate, 0.5M, saturated with CO2, at standard temperature and pressure: (CO2) = 1M; (H2CO3) = 0,038M; (HCO3-) = 0,336M; (CO3 --) = 0,34M; pH = 7.33, an overall concentration = 1,714M, more than three times that of the initial solution. It is in such conditions that the conversion of carbon dioxide by the hydrogen produced in situ by electrolysis, in fuel, must be done in the presence of catalyst, under UV radiation. For electrodes, a nano-porous layer was formed on their surface to receive the suitable catalyst. These lats prepared, are made of porous supports (montmorillonite, aluminum and silicon oxides) into which are inserted the metal precursor, by impregnation interactive, in Iron, cobalt, nickel salt solutions, cobalt, nickel. Their performance has been identified by the reduction of para- nitrophenol, to para-aminophenol in aqueous medium in the presence of sodium borohydride. This is the catalyst 'Cobalt supported by SiO2'' that gave the best conversion, 99.5% instead of 99.7%, for a platinum catalyst. The separation of hydrocarbon products, in the considered aqueous medium, continuously, has been studied to determine optimum conditions by pervaporation. For this purpose, membranes of poly-sulfone and poly-dimethylsiloxane, were prepared and characterized in terms of flow pervaporat (J), and solute / solvent separation factor (α). Thus, the developed membranes have equivalent performance to commercial membranes. More accurate results will be the subject of this communication.

Nitrogen trifluoride global emissions estimated from updated atmospheric measurements

PubMed Central

Arnold, Tim; Harth, Christina M.; Mühle, Jens; Manning, Alistair J.; Salameh, Peter K.; Kim, Jooil; Ivy, Diane J.; Steele, L. Paul; Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Baggenstos, Daniel; Weiss, Ray F.

2013-01-01

Nitrogen trifluoride (NF3) has potential to make a growing contribution to the Earth’s radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF3 in 2011 were 1.18 ± 0.21 Gg⋅y−1, or ∼20 Tg CO2-eq⋅y−1 (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF3). The 2011 global mean tropospheric dry air mole fraction was 0.86 ± 0.04 parts per trillion, resulting from an average emissions growth rate of 0.09 Gg⋅y−2 over the prior decade. In terms of CO2 equivalents, current NF3 emissions represent between 17% and 36% of the emissions of other long-lived fluorinated compounds from electronics manufacture. We also estimate that the emissions benefit of using NF3 over hexafluoroethane (C2F6) in electronics manufacture is significant—emissions of between 53 and 220 Tg CO2-eq⋅y−1 were avoided during 2011. Despite these savings, total NF3 emissions, currently ∼10% of production, are still significantly larger than expected assuming global implementation of ideal industrial practices. As such, there is a continuing need for improvements in NF3 emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing. PMID:23341630

Analyses of the Integration of Carbon Dioxide Removal Assembly, Compressor, Accumulator and Sabatier Carbon Dioxide Reduction Assembly

NASA Technical Reports Server (NTRS)

Jeng, Frank F.; Lafuse, Sharon; Smith, Frederick D.; Lu, Sao-Dung; Knox, James C.; Campbell, Mellssa L.; Scull, Timothy D.; Green Steve

2010-01-01

A tool has been developed by the Sabatier Team for analyzing/optimizing CO2 removal assembly, CO2 compressor size, its operation logic, water generation from Sabatier, utilization of CO2 from crew metabolic output, and Hz from oxygen generation assembly. Tests had been conducted using CDRA/Simulation compressor set-up at MSFC in 2003. Analysis of test data has validated CO2 desorption rate profile, CO2 compressor performance, CO2 recovery and CO2 vacuum vent in CDRA desorption. Optimizing the compressor size and compressor operation logic for an integrated closed air revitalization system Is being conducted by the Sabatier Team.

Spray process for the recovery of CO.sub.2 from a gas stream and a related apparatus

DOEpatents

Soloveichik, Grigorii Lev; Perry, Robert James; Wood, Benjamin Rue; Genovese, Sarah Elizabeth

2014-02-11

A method for recovering carbon dioxide (CO.sub.2) from a gas stream is disclosed. The method includes the step of reacting CO.sub.2 in the gas stream with fine droplets of a liquid absorbent, so as to form a solid material in which the CO.sub.2 is bound. The solid material is then transported to a desorption site, where it is heated, to release substantially pure CO.sub.2 gas. The CO.sub.2 gas can then be collected and used or transported in any desired way. A related apparatus for recovering carbon dioxide (CO.sub.2) from a gas stream is also described herein.

Carbon dioxide (CO2) sequestration in deep saline aquifers and formations: Chapter 3

USGS Publications Warehouse

Rosenbauer, Robert J.; Thomas, Burt

2010-01-01

Carbon dioxide (CO2) capture and sequestration in geologic media is one among many emerging strategies to reduce atmospheric emissions of anthropogenic CO2. This chapter looks at the potential of deep saline aquifers – based on their capacity and close proximity to large point sources of CO2 – as repositories for the geologic sequestration of CO2. The petrochemical characteristics which impact on the suitability of saline aquifers for CO2 sequestration and the role of coupled geochemical transport models and numerical tools in evaluating site feasibility are also examined. The full-scale commercial CO2 sequestration project at Sleipner is described together with ongoing pilot and demonstration projects.

Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations: Implications to future ecosystem functioning and paleoceanographic interpretations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernhard, Joan M.; Mollo-Christensen, Elizabeth; Eisenkolb, Nadine

2009-02-01

Increases in the partial pressure of carbon dioxide (pCO2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO2 is to sequester CO2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species (Allogromia laticollaris) was conducted to beginmore » to ascertain the effect of elevated pCO2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO2 (15000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~375 ppm CO2) were executed simultaneously. Although the experimental elevated pCO2 values are far above foreseeable surface water pCO2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO2 for 12 days were transferred to atmospheric conditions for ~24 h, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric control treatment. Incubation in 200 000 ppm CO2 also resulted in reproduction by some individuals. Results suggest that certain Foraminifera are able to tolerate deep-sea CO2 sequestration and perhaps thrive as a result of elevated pCO2 that is predicted for the next few centuries, in a high-pCO2 world. Thus, allogromiid foraminiferal blooms may result from climate change. Furthermore, because allogromiids consume a variety of prey, it is likely that they will be major players in ecosystem dynamics of future coastal sedimentary environments.« less

Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations: Implications to future ecosystem functioning and paleoceanographic interpretations

NASA Astrophysics Data System (ADS)

Bernhard, Joan M.; Mollo-Christensen, Elizabeth; Eisenkolb, Nadine; Starczak, Victoria R.

2009-02-01

Increases in the partial pressure of carbon dioxide (pCO 2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric-oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO 2 is to sequester CO 2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean-atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species ( Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO 2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO 2 (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~ 375 ppm CO 2) were executed simultaneously. Although the experimental elevated pCO 2 values are far above foreseeable surface water pCO 2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO 2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO 2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO 2 for 12 days were transferred to atmospheric conditions for ~ 24 h, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric control treatment. Incubation in 200 000 ppm CO 2 also resulted in reproduction by some individuals. Results suggest that certain Foraminifera are able to tolerate deep-sea CO 2 sequestration and perhaps thrive as a result of elevated pCO 2 that is predicted for the next few centuries, in a high-pCO 2 world. Thus, allogromiid foraminiferal "blooms" may result from climate change. Furthermore, because allogromiids consume a variety of prey, it is likely that they will be major players in ecosystem dynamics of future coastal sedimentary environments.

Optimizing supercritical carbon dioxide in the inactivation of bacteria in clinical solid waste by using response surface methodology.

PubMed

Hossain, Md Sohrab; Nik Ab Rahman, Nik Norulaini; Balakrishnan, Venugopal; Alkarkhi, Abbas F M; Ahmad Rajion, Zainul; Ab Kadir, Mohd Omar

2015-04-01

Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concentrations of tocols and γ-oryzanol compounds in rice bran oil obtained by fractional extraction with supercritical carbon dioxide.

PubMed

Yoon, Sung Won; Pyo, Young-Gil; Lee, Junsoo; Lee, Jeom-Sig; Kim, Byung Hee; Kim, In-Hwan

2014-01-01

Rice bran oil (RBO) is a good source of several commercially important bioactive phytochemicals, such as tocols (i.e. tocopherols and tocotrienols) and ferulic esters of sterols (i.e. γ-oryzanol). The aims of the present study were to examine the effects of different pressure and temperature combinations on the fractional extraction of RBO using supercritical carbon dioxide (SC-CO2) and to assess the levels of tocols homologues and γ-oryzanol components in the resulting oil fractions. Fractional extraction of rice bran oil was performed using SC-CO2 at either 27.6 or 41.4 MPa and either 40 or 60°C. The effects of the four different pressure and temperature combinations on the levels of seven tocols homologues (α-, β-, γ- and δ-tocopherol and α-, γ- and δ-tocotrienol) and the four major components of γ-oryzanol in the resulting oil fractions were investigated. Superior extraction efficiency was obtained using the higher pressure of 41.4 MPa. The tocols (particularly α-tocopherol and α-tocotrienol) were recovered early in the extraction process, while the γ-oryzanol compounds were obtained in the later stages. With regard to SC-CO2 extraction, tocols are more soluble than γ-oryzanol components, α-tocopherol is the most soluble of the tocols and the four γ-oryzanol components all have similar solubilities. Valuable data on solubilities of tocols homologues in SC-CO2 were provided from present study.

Making a case for telehealth: measuring the carbon cost of health-related travel.

PubMed

Ellis, Isabelle; Cheek, Colleen; Jaffray, Linda; Skinner, Timothy

2013-01-01

Telehealth services are promoted to reduce the cost of travel for people living in rural areas. The previous Australian Government, through the national Digital Economy Strategy, invested heavily in telehealth service development, at the same time introducing a carbon pricing mechanism. In planning a range of new telehealth services to a rural community the authors sought to quantify the travel conducted by people from one rural area in Australia to access health care, and to calculate the associated carbon emissions. A population survey was conducted over a 1-week period of health-related travel events for the year 1 July 2011 to 30 June 2012 of all households on King Island, a community situated between the Australian mainland state of Victoria and the state of Tasmania. Validated emissions calculators were sourced from the Carbon Neutral website, including the vehicle and fuel use calculator and air travel carbon calculator, to calculate the total emissions associated with the fuel burned in tonnes of carbon dioxide equivalent (tCO2e). Thirty nine percent of the population (625 participants) reported a total of 511 healthcare-related travel events. Participants travelled a total of 346 573 km and generated 0.22 tCO2e per capita. Participants paid the cost of their own travel more than 70% of the time. Dependence on fossil fuels for transport in a carbon economy has a significant impact on total healthcare carbon emissions. Alternative models of care, such as telehealth, need be developed for an environmentally sustainable healthcare system for rural and remote areas.

Removing Traffic Emissions from CO2 Time Series Measured at a Tall Tower Using on-Road Measurements and WRF-Stilt Transport Modeling

NASA Astrophysics Data System (ADS)

Schmidt, A.; Rella, C.; Goeckede, M.; Hanson, C. V.; Yang, Z.; Law, B. E.

2014-12-01

In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (±1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

Elevated CO2 induces alteration in lignin accumulation in celery (Apium graveolens L.).

PubMed

Liu, Jie-Xia; Feng, Kai; Wang, Guang-Long; Xu, Zhi-Sheng; Wang, Feng; Xiong, Ai-Sheng

2018-06-01

Carbon dioxide (CO 2 ) is an important regulator of plant growth and development, and its proportion in the atmosphere continues to rise now. Lignin is one of the major secondary products in plants with vital biological functions. However, the relationship between CO 2 level and xylogenesis in celery is still unknown. In order to investigate the effects of increasing CO 2 concentration on lignin accumulation in celery, 'Jinnanshiqin' were exposed to two CO 2 applications, 400 (e 0 ) and 1000 μmol mol -1 (e 1 ), respectively. Plant morphology and lignin distribution in celery plants treated with elevated CO 2 did not change significantly. There was an upward trend on lignin content in celery leaves, and the transcript abundance of 12 genes involved in lignin metabolism has altered in response to elevated CO 2 . The effects of high level of CO 2 on different tissues were different. Our works confirmed that CO 2 may play an important role in lignin accumulation in celery leaves. The current study will offer new evidence to understand the regulation mechanism of lignin biosynthesis under elevated CO 2 and provide a reference to improve celery quality by adjusting the growth environment. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

A database and probabilistic assessment methodology for carbon dioxide enhanced oil recovery and associated carbon dioxide retention in the United States

USGS Publications Warehouse

Warwick, Peter D.; Verma, Mahendra K.; Attanasi, Emil; Olea, Ricardo A.; Blondes, Madalyn S.; Freeman, Philip; Brennan, Sean T.; Merrill, Matthew; Jahediesfanjani, Hossein; Roueche, Jacqueline; Lohr, Celeste D.

2017-01-01

The U.S. Geological Survey (USGS) has developed an assessment methodology for estimating the potential incremental technically recoverable oil resources resulting from carbon dioxide-enhanced oil recovery (CO2-EOR) in reservoirs with appropriate depth, pressure, and oil composition. The methodology also includes a procedure for estimating the CO2 that remains in the reservoir after the CO2-EOR process is complete. The methodology relies on a reservoir-level database that incorporates commercially available geologic and engineering data. The mathematical calculations of this assessment methodology were tested and produced realistic results for the Permian Basin Horseshoe Atoll, Upper Pennsylvanian-Wolfcampian Play (Texas, USA). The USGS plans to use the new methodology to conduct an assessment of technically recoverable hydrocarbons and associated CO2 sequestration resulting from CO2-EOR in the United States.

Development Status for a Combined Solid Oxide Co-Electrolyzer and Carbon Formation Reactor System for Oxygen Regeneration

NASA Technical Reports Server (NTRS)

Green, Robert D.; Matter, Paul H.; Holt, Chris; Beachy, Michael; Gaydos, James; Farmer, Serene C.; Setlock, John

2016-01-01

A critical component in spacecraft life support loop closure is the removal of carbon dioxide (CO2, produced by the crew) from the cabin atmosphere and chemical reduction of this CO2 to recover the oxygen. In 2015, we initiated development of an oxygen recovery system for life support applications consisting of a solid oxide co-electrolyzer (SOCE) and a carbon formation reactor (CFR). The SOCE electrolyzes a combined stream of carbon dioxide (CO2) and water (H2O) gas mixtures to produce synthesis gas (e.g., CO and H2 gas) and pure dry oxygen as separate products. This SOCE is being developed from a NASA GRC solid oxide fuel cell and stack design originally developed for aeronautics long-duration power applications. The CFR, being developed by pHMatter LLC, takes the CO and H2 output from the SOCE, and converts it primarily to solid carbon (C(s)) and H2O and CO2. Although the solid carbon accumulates in the CFR, the innovative design allows easy removal of the carbon product, requiring minimal crew member (CM) time and low resupply mass (1.0 kg/year/CM) for replacement of the solid carbon catalyst, a significant improvement over previous Bosch reactor approaches. In this work, we will provide a status of our Phase I efforts in the development and testing of both the SOCE and CFR prototype units, along with an initial assessment of the combined SOCE-CFR system, including a mass and power projections, along with an estimate of the oxygen recovery rate.

Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

PubMed

Moreira, Diana; Pires, José C M

2016-09-01

Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbon Dioxide Removal Troubleshooting aboard the International Space Station (ISS) during Space Shuttle (STS) Docked Operations

NASA Technical Reports Server (NTRS)

Matty, Christopher M.; Cover, John M.

2009-01-01

The International Space Station (ISS) represents a largely closed-system habitable volume which requires active control of atmospheric constituents, including removal of exhaled Carbon Dioxide (CO2). The ISS provides a unique opportunity to observe system requirements for (CO2) removal. CO2 removal is managed by the Carbon Dioxide Removal Assembly (CDRA) aboard the US segment of ISS and by Lithium Hydroxide (LiOH) aboard the Space Shuttle (STS). While the ISS and STS are docked, various methods are used to balance the CO2 levels between the two vehicles, including mechanical air handling and management of general crew locations. Over the course of ISS operation, several unexpected anomalies have occurred which have required troubleshooting, including possible compromised performance of the CDRA and LiOH systems, and possible imbalance in CO2 levels between the ISS and STS while docked. This paper will cover efforts to troubleshoot the CO2 removal systems aboard the ISS and docked STS.

Efficiency of Carbon Dioxide Fractional Laser in Skin Resurfacing.

PubMed

Petrov, Andrej

2016-06-15

The aim of the study was to confirm the efficiency and safety of the fractional CO2 laser in skin renewal and to check the possibility of having a synergistic effect in patients who besides carbon dioxide laser are treated with PRP (platelet-rich plasma) too. The first group (Examined Group 1 or EG1) included 107 patients treated with fractional CO2 laser (Lutronic eCO2) as mono-therapy. The second group (Control Group or CG) covered 100 patients treated with neither laser nor plasma in the same period but subjected to local therapy with drugs or other physio-procedures under the existing protocols for treatment of certain diseases. The third group (Examined Group 2 or EG2) treated 25 patients with combined therapy of CO2 laser and PRP in the treatment of facial rejuvenation or treatment of acne scars. Patient's satisfaction, in general, is significantly greater in both examined groups (EG1 and EG2) (p < 0.001). It was found the significant difference between control and examined group from the treatment in acne scar (Fisher exact two tailed p < 0.001). Patients satisfaction with the treatment effect in rejuvenation of the skin is significant (χ2 = 39.41; df = 4; p < 0.001). But, patients satisfaction from the treatment with HPV on the skin was significantly lower in examined group (treated with laser), p = 0.0002. Multifunctional fractional carbon dioxide laser used in treatment of patients with acne and pigmentation from acne, as well as in the treatment of scars from different backgrounds, is an effective and safe method that causes statistically significant better effect of the treatment, greater patients' satisfaction, minimal side effects and statistically better response to the therapy, according to assessments by the patient and the therapist.

Collision and radiative processes in emission of atmospheric carbon dioxide

NASA Astrophysics Data System (ADS)

Smirnov, B. M.

2018-05-01

The peculiarities of the spectroscopic properties of CO2 molecules in air due to vibration-rotation radiative transitions are analyzed. The absorption coefficient due to atmospheric carbon dioxide and other atmospheric components is constructed within the framework of the standard atmosphere model, on the basis of classical molecular spectroscopy and the regular model for the spectroscopy absorption band. The radiative flux from the atmosphere toward the Earth is represented as that of a blackbody, and the radiative temperature for emission at a given frequency is determined with accounting for the local thermodynamic equilibrium, a small gradient of the tropospheric temperature and a high optical thickness of the troposphere for infrared radiation. The absorption band model with an absorption coefficient averaged over the frequency and line-by-line model are used for evaluating the radiative flux from the atmosphere to the Earth which values are nearby for these models and are equal W m‑2 for the contemporary concentration of atmospheric CO2 molecules and W m‑2 at its doubled value. The absorption band model is not suitable to calculate the radiative flux change at doubling of carbon dioxide concentration because averaging over oscillations decreases the range where the atmospheric optical thickness is of the order of one, and just this range determines this change. The line-by-line method gives the change of the global temperature K as a result of doubling the carbon dioxide concentration. The contribution to the global temperature change due to anthropogenic injection of carbon dioxide in the atmosphere, i.e. resulted from combustion of fossil fuels, is approximately 0.02 K now.

Performance of an exhaled nitric oxide and carbon dioxide sensor using quantum cascade laser-based integrated cavity output spectroscopy.

PubMed

McCurdy, Matthew R; Bakhirkin, Yury; Wysocki, Gerard; Tittel, Frank K

2007-01-01

Exhaled nitric oxide (NO) is an important biomarker in asthma and other respiratory disorders. The optical performance of a NOCO(2) sensor employing integrated cavity output spectroscopy (ICOS) with a quantum cascade laser operating at 5.22 microm capable of real-time NO and CO(2) measurements in a single breath cycle is reported. A NO noise-equivalent concentration of 0.4 ppb within a 1-sec integration time is achieved. The off-axis ICOS sensor performance is compared to a chemiluminescent NO analyzer and a nondispersive infrared (NDIR) CO(2) absorption capnograph. Differences between the gas analyzers are assessed by the Bland-Altman method to estimate the expected variability between the gas sensors. The off-axis ICOS sensor measurements are in good agreement with the data acquired with the two commercial gas analyzers. This work demonstrates the performance characteristics and merits of mid-infrared spectroscopy for exhaled breath analysis.

Carbon dioxide stimulation of photosynthesis in Liquidambar styraciflua is not sustained during a 12-year field experiment

DOE PAGES

Warren, Jeffrey M.; Jensen, Anna M.; Medlyn, Belinda E.; ...

2014-11-17

Elevated atmospheric CO 2 (eCO 2) often increases photosynthetic CO 2 assimilation (A) in field studies of temperate tree species, although there is evidence that the increases may decline through time due to biochemical and morphological acclimation, and environmental constraints. Indeed, at the free air CO 2 enrichment (FACE) study in Oak Ridge, Tennessee, A was increased in 12-year-old sweetgum trees following two years of ~40% enhancement of CO 2. A was re-assessed a decade later to determine if initial enhancement of eCO 2 was sustained through time. Measurements were conducted at prevailing CO 2 and temperature on detached, re-hydratedmore » branches using a portable gas exchange system. Photosynthetic CO 2 response curves (A versus the CO 2 concentration in the intercellular air space (C i); or A-C i curves) were contrasted with earlier measurements using consistent leaf photosynthesis model equations. We accessed relationships between light-saturated photosynthesis (A sat), maximum electron transport rate (J max), maximum Rubisco activity (V cmax) chlorophyll content and foliar nitrogen (N) and chlorophyll content. In 1999, light-saturated photosynthesis (A sat) for eCO 2 treatments was 15.4 ± 0.8 μmol m -2 s -1, 22% higher than aCO 2 treatments (P<0.01). By 2009, A sat declined to <50% of 1999 values, and there was no longer a significant effect of eCO 2 (A sat = 6.9 or 5.7 ± 0.7 μmol m -2 s -1 for eCO 2 or aCO 2, respectively). In 1999, there was no treatment effect on area-based foliar N; however, by 2008, N content in eCO 2 foliage was 17% less than in aCO 2 foliage. Photosynthetic N use efficiency (A sat:N) was greater in eCO 2 in 1999 resulting in greater A sat despite similar N content, but the enhanced efficiency in eCO 2 trees was lost as foliar N declined to sub-optimal levels. There was no treatment difference in the declining linear relationships between J max or V cmax with declining N, or in the ratio of J max:V cmax through time. Results suggest that initial enhancement of photosynthesis to elevated CO 2 will not be sustained through time if nitrogen becomes limited.« less

Chemical trends in background air quality and the ionic composition of precipitation for the period 1980-2004 from samples collected at Valentia Observatory, Co. Kerry, Ireland.

PubMed

Bashir, Wasim; McGovern, Frank; O'Brien, Phillip; Ryan, Margaret; Burke, Liam; Paull, Brett

2008-06-01

A major Irish study, based upon more than 8000 samples collected over the measurement period of 22 years, for sulfur dioxide (SO2-S), sulfate (SO4-S) and nitrogen dioxide (NO2-N) concentrations (microg m(-3)) within air, and the ionic composition of precipitation samples based on sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), chloride (Cl-), sulfate (SO4-S), non-sea salt sulfate (nssSO4-S), ammonium (NH4-N), and nitrate (NO3-N) weighted mean concentrations (mg l(-1)), has been completed. For the air samples, the sulfur dioxide and sulfate concentrations decreased over the sampling period (1980-2004) by 75% and 45%, respectively, whereas no significant trend was observed for nitrogen dioxide. The highest concentrations for sulfur dioxide, sulfate and nitrogen dioxide were associated with wind originating from the easterly and northeasterly directions i.e. those influenced by Irish and European sources. The lowest concentrations were associated with the westerly directions i.e. for air masses originating in the North Atlantic region. This was further verified with the use of backward (back) trajectory analysis, which allowed tracing the movement of air parcels using the European Centre for Medium range Weather Forecasting (ECMWF) ERA-40 re-analysis data. High non-sea salt sulfate levels were being associated with air masses originating from Europe (easterlies) with lower levels from the Atlantic (westerlies). With the precipitation data, analysis of the non-sea salt sulfate concentrations showed a decrease by 47% since the measurements commenced.

Short-term effects of carbon dioxide on carnation callus cell respiration. [Dianthus Caryophyllus L. ; Elodea canadensis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palet, A.; Ribas-Carbo, M.; Argiles, J.M.

1991-06-01

The addition of potassium bicarbonate to the electrode cuvette immediately stimulated the rate of dark O{sub 2} uptake of photomixotrophic and heterotrophic carnation (Dianthus caryophyllus L.) callus, of Elodea canadensis (Minchx) leaves, and of other plant tissues. This phenomenon occurred at pH values lower than 7.2 to 7.8, and the stimulation depended on the concentration of gaseous CO{sub 2} in the solution. These stimulatory responses lasted several minutes and then decreased, but additional bicarbonate or gaseous CO{sub 2} again stimulated respiration, suggesting a reversible effect. Carbonic anhydrase in the solution increased the stimulatory effect of potassium bicarbonate. The CO{sub 2}/bicarbonatemore » dependent stimulation of respiration did not occur in animal tissues such as rat diaphragm and isolated hepatocytes, and was inhibited by salicylhydroxamic acid in carnation callus cells and E. canadensis leaves. This suggested that the alternative oxidase was engaged during the stimulation in plant tissues. The cytochrome pathway was severely inhibited by CO{sub 2}/bicarbonate either in the absence or in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone. The activity of cytochrome c oxidase of callus tissue homogenates was also inhibited by CO{sub 2}/bicarbonate. The results suggested that high carbon dioxide levels (mainly free CO{sub 2}) partially inhibited the cytochrome pathway (apparently at the oxidase level), and this block in electron transport elicited a large transient engagement of the alternative oxidase when present uninhibited.« less

Review of Quantitative Monitoring Methodologies for Emissions Verification and Accounting for Carbon Dioxide Capture and Storage for California’s Greenhouse Gas Cap-and-Trade and Low-Carbon Fuel Standard Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oldenburg, Curtis M.; Birkholzer, Jens T.

The Cap-and-Trade and Low Carbon Fuel Standard (LCFS) programs being administered by the California Air Resources Board (CARB) include Carbon Dioxide Capture and Storage (CCS) as a potential means to reduce greenhouse gas (GHG) emissions. However, there is currently no universal standard approach that quantifies GHG emissions reductions for CCS and that is suitable for the quantitative needs of the Cap-and-Trade and LCFS programs. CCS involves emissions related to the capture (e.g., arising from increased energy needed to separate carbon dioxide (CO 2) from a flue gas and compress it for transport), transport (e.g., by pipeline), and storage of COmore » 2 (e.g., due to leakage to the atmosphere from geologic CO 2 storage sites). In this project, we reviewed and compared monitoring, verification, and accounting (MVA) protocols for CCS from around the world by focusing on protocols specific to the geologic storage part of CCS. In addition to presenting the review of these protocols, we highlight in this report those storage-related MVA protocols that we believe are particularly appropriate for CCS in California. We find that none of the existing protocols is completely appropriate for California, but various elements of all of them could be adopted and/or augmented to develop a rigorous, defensible, and practical surface leakage MVA protocol for California. The key features of a suitable surface leakage MVA plan for California are that it: (1) informs and validates the leakage risk assessment, (2) specifies use of the most effective monitoring strategies while still being flexible enough to accommodate special or site-specific conditions, (3) quantifies stored CO 2, and (4) offers defensible estimates of uncertainty in monitored properties. California’s surface leakage MVA protocol needs to be applicable to the main CO 2 storage opportunities (in California and in other states with entities participating in California’s Cap-and-Trade or LCFS programs), specifically CO 2-enhanced oil recovery (CO 2-EOR), CO 2 injection into depleted gas reservoirs (with or without CO 2-enhanced gas recovery (CO 2-EGR)), as well as deep saline storage. Regarding the elements of an effective surface leakage MVA protocol, our recommendations for California are that: (1) both CO 2 and methane (CH 4) surface leakage should be monitored, especially for enhanced recovery scenarios, (2) emissions from all sources not directly related to injection and geologic storage (e.g., from capture, or pipeline transport) should be monitored and reported under a plan separate from the surface leakage MVA plan that is included as another component of the quantification methodology (QM), (3) the primary objective of the surface leakage MVA plan should be to quantify surface leakage of CO 2 and CH 4 and its uncertainty, with consideration of best-practices and state-of-the-art approaches to monitoring including attribution assessment, (4) effort should be made to monitor CO 2 storage and migration in the subsurface to anticipate future surface leakage monitoring needs, (5) detailed descriptions of specific monitoring technologies and approaches should be provided in the MVA plan, (6) the main purpose of the CO 2 injection project (CO 2-EOR, CO 2-EGR, or pure geologic carbon sequestration (GCS)) needs to be stated up front, (7) approaches to dealing with missing data and quantifying uncertainty need to be described, and (8) post-injection monitoring should go on for a period consistent with or longer than that prescribed by the U.S. EPA.« less

Divergent Responses of Forest Soil Microbial Communities under Elevated CO 2 in Different Depths of Upper Soil Layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Hao; He, Zhili; Wang, Aijie

Numerous studies have shown that the continuous increase of atmosphere CO 2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO 2 (eCO 2) at different soil depth profiles in forest ecosystems. In this paper, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO 2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO 2 significantly shifted the compositions, including phylogenetic and functional genemore » structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO 2 at both soil depths, although the stimulation effect of eCO 2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO 3-N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO 2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO 2 increases. The concentration of atmospheric carbon dioxide (CO 2) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO 2 (eCO 2) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO 2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial communities shifted under eCO 2 at both soil depths. Finally, more functional genes involved in carbon, nitrogen, and phosphorus cycling were stimulated under eCO 2 at the soil depth of 0 to 5 cm than at the depth of 5 to 15 cm.« less

Divergent Responses of Forest Soil Microbial Communities under Elevated CO 2 in Different Depths of Upper Soil Layers

DOE PAGES

Yu, Hao; He, Zhili; Wang, Aijie; ...

2017-10-27

Numerous studies have shown that the continuous increase of atmosphere CO 2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO 2 (eCO 2) at different soil depth profiles in forest ecosystems. In this paper, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO 2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO 2 significantly shifted the compositions, including phylogenetic and functional genemore » structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO 2 at both soil depths, although the stimulation effect of eCO 2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO 3-N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO 2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO 2 increases. The concentration of atmospheric carbon dioxide (CO 2) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO 2 (eCO 2) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO 2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial communities shifted under eCO 2 at both soil depths. Finally, more functional genes involved in carbon, nitrogen, and phosphorus cycling were stimulated under eCO 2 at the soil depth of 0 to 5 cm than at the depth of 5 to 15 cm.« less

Divergent Responses of Forest Soil Microbial Communities under Elevated CO2 in Different Depths of Upper Soil Layers.

PubMed

Yu, Hao; He, Zhili; Wang, Aijie; Xie, Jianping; Wu, Liyou; Van Nostrand, Joy D; Jin, Decai; Shao, Zhimin; Schadt, Christopher W; Zhou, Jizhong; Deng, Ye

2018-01-01

Numerous studies have shown that the continuous increase of atmosphere CO 2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO 2 (eCO 2 ) at different soil depth profiles in forest ecosystems. Here, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO 2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO 2 significantly shifted the compositions, including phylogenetic and functional gene structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO 2 at both soil depths, although the stimulation effect of eCO 2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO 3 -N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO 2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO 2 increases. IMPORTANCE The concentration of atmospheric carbon dioxide (CO 2 ) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO 2 (eCO 2 ) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO 2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial communities shifted under eCO 2 at both soil depths. More functional genes involved in carbon, nitrogen, and phosphorus cycling were stimulated under eCO 2 at the soil depth of 0 to 5 cm than at the depth of 5 to 15 cm. Copyright © 2017 American Society for Microbiology.

Monitoring gaseous exchange: implications for nursing care.

PubMed

Martin, Susan; Wilson, Michael

2002-02-01

The purpose of this study is to examine whether a relationship exists between arterial and end-tidal carbon dioxide tension (PaCO2 and PETCO2 respectively) in patients admitted to intensive care units (ICUs), and what the implications it has for nursing care. PaCO2 and PETCO2 are indicators of ventilatory adequacy which is an important aspect of respiratory function. These measures of carbon dioxide tension are obtained via invasive and non-invasive monitoring tools. Measurement of PETCO2 has only recently been introduced into ICUs and its usefulness in these environments is open to debate. A population of 30 intubated patients had 214 simultaneous measurements of PaCO2 and PETCO2 taken over a period of 10 months. The findings indicate that, despite strong significant correlations, PETCO2 cannot be used safely as a substitute for PaCO2 as the arterial/end-tidal carbon dioxide gradient is not constant, nor does capnography provide a consistently reliable indicator of PaCO2.

Simulating the potential for Carbon Dioxide (CO2) reduction by the application of environmentally friendly transportation (case study: Gatot Subroto Street, Medan City)

NASA Astrophysics Data System (ADS)

Suryati, Isra; Turmuzi Lubis, Muhammad; Mawaddah, Nurul

2018-03-01

Carbon Dioxide (CO2) is one of the greenhouse gases. One source of greenhouse gases comes from the use of fossil fuels from the transport sector. The transportation sector is one of the dominant sectors in contributing to the greenhouse effect. This study aims to calculate the amount of CO2 from transportation activities by using mobile six equations in Gatot Subroto Street, Medan City. A sampling of CO2 concentration was done using Carbon Dioxide Monitor with Non-Dispersive Infra Red (NDIR) Analyzer method. Also, a simulation of the reduction of the number of private vehicles to mass transportation such as BRT gas-fired. The results showed CO2 emissions calculations with mobile six ranged from 47.2 kg CO2 - 978.2 kg CO2. Meanwhile, measurements range from 3,004 ppm - 3,405 ppm. Implementation of the concept of environmentally friendly transportation such as BRT in Gatot Subroto Street, Medan City will be able to reduce the average emissions load CO2 by 42.75% -78.80%. Based on the calculation simulation in this study is estimated the number of BRT required approximately 71 units.

Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes

DOEpatents

Fuller, Timothy J.; Jiang, Ruichun

2017-01-24

A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

Sustainable Transportation Fuels from Natural Gas (H{sub 2}), Coal and Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huffman, Gerald

2012-12-31

This research program is focused primarily on the conversion of coal, natural gas (i.e., methane), and biomass to liquid fuels by Fischer-Tropsch synthesis (FTS), with minimum production of carbon dioxide. A complementary topic also under investigation is the development of novel processes for the production of hydrogen with very low to zero production of CO{sub 2}. This is in response to the nation's urgent need for a secure and environmentally friendly domestic source of liquid fuels. The carbon neutrality of biomass is beneficial in meeting this goal. Several additional novel approaches to limiting carbon dioxide emissions are also being explored.

Characterization of amine-functionalized electrode for aqueous carbon dioxide (CO2) direct detection

NASA Astrophysics Data System (ADS)

Sato, Hiroshi

2017-03-01

In this study, fabrication of amino groups and ferrocenes co-modified sensor electrode and electrochemical detection of carbon dioxide (CO2) in the saline solution is reported. Electrochemical detection of CO2 was carried out using cyclic voltammetry in saline solution containing sodium bicarbonate as CO2 source. Oxidation and reduction peak current intensities computed from cyclic voltammograms varied as a function of concentration of CO2 molecules. The calibration curve was obtained by plotting oxidation peak current intensities as a function of CO2 concentration. The sensor electrode prepared in this study can estimate the differences between concentrations of CO2 in normal seawater up to 10 times higher. Furthermore, the surface analysis was performed to clarify the CO2 detection mechanism.

Compatibility of Medical-Grade Polymers with Dense CO2

PubMed Central

Jiménez, A; Thompson, G L; Matthews, M A; Davis, T A; Crocker, K; Lyons, J S; Trapotsis, A

2009-01-01

This study reports the effect of exposure to liquid carbon dioxide on the mechanical properties of selected medical polymers. The tensile strengths and moduli of fourteen polymers are reported. Materials were exposed to liquid CO2, or CO2 + trace amounts of aqueous H2O2, at 6.5 MPa and ambient temperature. Carbon dioxide uptake, swelling, and distortion were observed for the more amorphous polymers while polymers with higher crystallinity showed little effect from CO2 exposure. Changes in tensile strength were not statistically significant for most plastics, and most indicated good tolerance to liquid CO2. These results are relevant to evaluating the potential of liquid CO2-based sterilization technology. PMID:19756235

Descriptors and Thermodynamic Limitations of Electrocatalytic Carbon Dioxide Reduction on Rutile Oxide Surfaces.

PubMed

Bhowmik, Arghya; Vegge, Tejs; Hansen, Heine A

2016-11-23

A detailed understanding of the electrochemical reduction of CO 2 into liquid fuels on rutile metal oxide surfaces is developed by using DFT calculations. We consider oxide overlayer structures on RuO 2 (1 1 0) surfaces as model catalysts to elucidate the trends and limitations in the CO 2 reduction reaction (CO2RR) based on thermodynamic analysis. We aim to specify the requirements for CO2RR catalysts to establish adsorbate scaling relations and use these to derive activity volcanoes. Computational results show that the OH* binding free energy is a good descriptor of the thermodynamic limitations and it defines the left leg of the activity volcano for CO2RR. HCOOH* is a key intermediate for products formed through further reduction, for example, methanediol, methanol, and methane. The surfaces that do not bind HCOOH* are selective towards formic acid (HCOOH) production, but hydrogen evolution limits their suitability. We determine the ideal binding free energy for H* and OH* to facilitate selective CO2RR over H 2 /CO evolution to be ΔG B [H]>0.5 eV and -0.5 eV<ΔG B [OH]<0.1 eV. The Re-containing overlayers considered in this work display excellent promise for selectivity, although they are active at a highly reducing potential. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

76 FR 70429 - Notice of Intent To Prepare an Environmental Impact Statement and Notice of Potential Floodplain...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... associated with delivery of feed materials and distribution of products (e.g., access roads, pipelines... Generating Station (Parish Plant) in Fort Bend County, Texas; deliver the CO 2 via a new pipeline to the... tons) of the CO 2 annually from a 250-megawatt equivalent (MWe) flue gas slip stream taken from the 617...

Biological acetate production from carbon dioxide by Acetobacterium woodii and Clostridium ljungdahlii: The effect of cell immobilization.

PubMed

Cheng, Hai-Hsuan; Syu, Jyun-Cyuan; Tien, Shih-Yuan; Whang, Liang-Ming

2018-08-01

This study investigated the acetate production from gas mixture of hydrogen (H 2 ) and carbon dioxide (CO 2 ) in the ratio of 7:3 using two acetogens: Acetobacterium woodii and Clostridium ljungdahlii. Batch result shows A. woodii performed two-phase degradation with the presence of glucose that lactate was produced from glucose and was reutilized for the production of butyrate and few acetate, while only acetate was detected when providing gas mixture. C. ljungdahlii produced butyrate and ethanol along with acetate when glucose was introduced, while only ethanol and acetate were found by feeding gas mixture. The acetate-to-ethanol (A/E) ratio can be enhanced by cell immobilization, while GAC immobilization produced only acetate and the production rate reached 0.072 mmol/d under fed-batch operation. Acetate production rate increased from 18 to 28 mmol/L/d with GAC immobilization when gas flowrate increased from 100 to 300 mL/min in anaerobic fluidized membrane bioreactor (AFMBR), and a highest A/E ratio of 30 implies the possible application of acetate recovery from H 2 and CO 2 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Emissions of Water and Carbon Dioxide from Fossil-Fuel Combustion Contribute Directly to Ocean Mass and Volume Increases

NASA Astrophysics Data System (ADS)

Skuce, A. G.

2014-12-01

The direct, non-climate, contribution of carbon dioxide and water emissions from fossil-fuel (FF) combustion to the volume and mass of the oceans has been omitted from estimates of sea-level rise (SLR) in IPCC reports. Following the method of Gornitz et al. (1997), H2O emissions are estimated using carbon emissions from the Carbon Dioxide Information Analysis Center, along with typical carbon and hydrogen contents of FF. Historic H2O emissions from 1750 to 2010 amount to 430 ±50 PgH2O, equivalent to 1.2 ±0.2 mmSLR. Sometime in this decade the volume of H2O from historic FF combustion will exceed the volume of Lake Erie (480 km3). CO2 dissolved in the ocean increases the seawater volume by 31-33 mL mol-1 CO2. From 1750 to 2010, 370 ±70 PgCO2 from FF combustion has dissolved in the oceans, causing 0.7 ±0.2 mmSLR. Combined H2O+CO2emissions from FF have therefore added 1.9 ±0.4 mm to sea levels in the Industrial Era. Combustion of FF in 2010 resulted in emissions of 32 PgCO2 and 12 ±1 PgH2O. SLR contributions for that year from FF emissions were 0.033 ±0.005 mm from H2O and 0.011±0.003 mm from dissolved CO2, a total rate of 0.044 ±0.008 mm yr-1. Emissions incorporated in socio-economic models underlying the RCP 8.5 and 2.6 scenarios are used along with concentration-driven CMIP5 Earth System Models results to estimate future sea-level rise from FF combustion. From 2010 to 2100, RCP8.5 and 2.6 models respectively produce 9 ±2 mmSLR and 5 ±1 mmSLR from FF H2O+CO2. For perspective, these amounts are larger than the modelled contributions from loss of glaciers in the Andes. The direct contribution of FF emissions to SLR is small (1-2%) relative to current rates and projected estimates under RCP scenarios up to 2100. The magnitude is similar to SLR estimates from other minor sources such as the melting of floating ice, land-use emissions and produced water from oil operations, none of which are currently included in SLR assessments. As uncertainties in observations and contributions are reduced, small contribution factors, hitherto neglected, will become relatively more important in balancing the books. ReferenceGornitz, V., C. Rosenzweig, and D. Hillel, 1997: Effects of anthropogenic intervention in the land hydrological cycle on global sea level rise. Global and Planetary Change, 14, 147-161. DOI: 10.1016/S0921-8181(96)00008-2

Carbon dioxide enhanced oil recovery performance according to the literature

USGS Publications Warehouse

Olea, Ricardo A.

2017-07-17

IntroductionThe need to increase the efficiency of oil recovery and environmental concerns are bringing to prominence the use of carbon dioxide (CO2) as a tertiary recovery agent. Assessment of the impact of flooding with CO2 all eligible reservoirs in the United States not yet undergoing enhanced oil recovery (EOR) requires making the best possible use of the experience gained in 40 years of applications. Review of the publicly available literature has located relevant CO2-EOR information for 53 units (fields, reservoirs, pilot areas) in the United States and 17 abroad.As the world simultaneously faces an increasing concentration of CO2 in the atmosphere and a higher demand for fossil fuels, the CO2-EOR process continues to gain popularity for its efficiency as a tertiary recovery agent and for the potential for having some CO2 trapped in the subsurface as an unintended consequence of the enhanced production (Advanced Resources International and Melzer Consulting, 2009). More extensive application of CO2-EOR worldwide, however, is not making it significantly easier to predict the exact outcome of the CO2 flooding in new reservoirs. The standard approach to examine and manage risks is to analyze the intended target by conducting laboratory work, running simulation models, and, finally, gaining field experience with a pilot test. This approach, though, is not always possible. For example, assessment of the potential of CO2-EOR at the national level in a vast country such as the United States requires making forecasts based on information already available.Although many studies are proprietary, the published literature has provided reviews of CO2-EOR projects. Yet, there is always interest in updating reports and analyzing the information under new perspectives. Brock and Bryan (1989) described results obtained during the earlier days of CO2-EOR from 1972 to 1987. Most of the recovery predictions, however, were based on intended injections of 30 percent the size of the reservoir’s hydrocarbon pore volume (HCPV), and the predictions in most cases badly missed the actual recoveries because of the embryonic state of tertiary recovery in general and CO2 flooding in particular at the time. Brock and Bryan (1989), for example, reported for the Weber Sandstone in the Rangely oil field in Colorado, an expected recovery of 7.5 percent of the original oil in place (OOIP) after injecting a volume of CO2 equivalent to 30 percent of the HCPV, but Clark (2012) reported that after injecting a volume of CO2 equivalent to 46 percent of the HCPV, the actual recovery was 4.8 percent of the OOIP. Decades later, the numbers by Brock and Bryan (1989) continue to be cited as part of expanded reviews, such as the one by Kuuskraa and Koperna (2006). Other comprehensive reviews including recovery factors are those of Christensen and others (2001) and Lake and Walsh (2008). The Oil and Gas Journal (O&GJ) periodically reports on active CO2-EOR operations worldwide, but those releases do not include recovery factors. The monograph by Jarrell and others (2002) remains the most technically comprehensive publication on CO2 flooding, but it does not cover recovery factors either.This chapter is a review of the literature found in a search for information about CO2-EOR. It has been prepared as part of a project by the U.S. Geological Survey (USGS) to assess the incremental oil production that would be technically feasible by CO2 flooding of all suitable oil reservoirs in the country not yet undergoing tertiary recovery.

The importance of determining carbon sequestration and greenhouse gas mitigation potential in ornamental horticulture

USDA-ARS?s Scientific Manuscript database

Over the past three decades, one issue which has received significant attention from the scientific community is climate change and the possible impacts on the global environment. Increased atmospheric carbon dioxide (CO2) concentration, along with other trace gases [i.e., methane (CH4) and nitrous ...

Strategies for Carbon Sequestration and Reducing Greenhouse Gas Emissions from Nursery Production Systems

USDA-ARS?s Scientific Manuscript database

Over the past three decades, no issue has received more attention from the scientific community than global warming and the possible impacts it may have on the global environment. Increased atmospheric carbon dioxide (CO2) concentration, along with those of other trace gases [i.e., methane (CH4), an...

A comparison of emissions from vehicles fueled with diesel or compressed natural gas.

PubMed

Hesterberg, Thomas W; Lapin, Charles A; Bunn, William B

2008-09-01

A comprehensive comparison of emissions from vehicles fueled with diesel or compressed natural gas (CNG) was developed from 25 reports on transit buses, school buses, refuse trucks, and passenger cars. Emissions for most compounds were highest for untreated exhaust emissions and lowest for treated exhaust CNG buses without after-treatment had the highest emissions of carbon monoxide, hydrocarbons, nonmethane hydrocarbons (NMHC), volatile organic compounds (VOCs; e.g., benzene, butadiene, ethylene, etc.), and carbonyl compounds (e.g., formaldehyde, acetaldehyde, acrolein). Diesel buses without after-treatment had the highest emissions of particulate matter and polycyclic aromatic hydrocarbons (PAHs). Exhaust after-treatments reduced most emissions to similar levels in diesel and CNG buses. Nitrogen oxides (NO(x)) and carbon dioxide (CO2) emissions were similar for most vehicle types, fuels, and exhaust after-treatments with some exceptions. Diesel school buses had higher CO2 emissions than the CNG bus. CNG transit buses and passenger cars equipped with three-way catalysts had lower NO(x) emissions. Diesel buses equipped with traps had higher nitrogen dioxide emissions. Fuel economy was best in the diesel buses not equipped with exhaust after-treatment.

SEM-EDS Observation of Structure Changes in Synthetic Zeolites Modified for CO2 Capture Needs

NASA Astrophysics Data System (ADS)

Wdowin, Magdalena; Panek, Rafal; Franus, Wojciech

Carbon dioxide is the main greenhouse gas and its amount still increase in the atmosphere. Air pollution and greenhouse effect caused by CO2 emission have become a major threat to the environment on a global scale. Carbon dioxide sequestration (i.e. capture and consequently geological storage) is the key strategy within the portfolio of actions to reduce CO2 emission to the atmosphere. The most costly stage is capture of CO2, therefore there is a need to search new solutions of this technology. For this purpose it was examined Na-X synthetic zeolites, that were silver and PEI (polyethyleneimine) activated. SEM-EDS investigation enable to find a changes in structure of this materials after treatment. Where, as a result of silver activation from EDS analysis it is seen that Ag occur in Na-X structure, what indicate a substitution of Ag2+ for Na+ ions in crystal lattice. Analysing wt% the EDS analysis has shown that zeolite Na-X after silver impregnation becomes Ag-X zeolite. For Na-X-PEI activated it is observed a distinct organic compound in the form of coatings on Na-X crystals causing a sealing of pores in tested zeolite. Further examination of these materials concern determination of surface properties and experiments of CO2 sorption. But SEM-EDS analysis enable to determine the extent of activation, what is very important in determination of optimal conditions for such treatment in order to obtain better sorbent of CO2.

Fabrication of water-repellent cellulose fiber coated with magnetic nanoparticles under supercritical carbon dioxide

NASA Astrophysics Data System (ADS)

Xu, Shengjie; Shen, Danping; Wu, Peiyi

2013-04-01

Hematite nanoparticle-coated magnetic composite fiber was prepared in supercritical carbon dioxide (scCO2). With the help of scCO2, cellulose did not need to be dissolved and regenerated and it could be in any form (e.g., cotton wool, filter paper, textile, etc.). The penetrating and swelling effect of scCO2, the slowing reaction rate of weak alkalis, and the template effect of cellulose fibers were discovered to be the key factors for the fabrication of ordered cellulose/Fe2O3 composite fibers. The structures of the composite fibers as well as the layers of Fe2O3 particles were characterized by means of scanning/transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman investigation. It was found that α-Fe2O3 granules which ranged from 30 to 85 nm with average diameter around 55 nm would be generated on the surface of cellulose fibers via potassium acetate, while irregular square prisms (ranged from 200 to 600 nm) which were composed of smaller nanoparticles ( 10 nm) would be fabricated via urea. And, the obtained composite was highly water repellent with superparamagnetic or ferromagnetic properties.

Enantioselective Allylation of (2E,4E)-2,4-Dimethylhexadienal: Synthesis of (5R,6S)-(+)-Pteroenone.

PubMed

Koukal, Petr; Kotora, Martin

2015-05-11

Allylation, trans- and cis-crotylation of (2E,4E)-2,4-dimethylhexadienal, a representative α,β,γ,δ-unsaturated aldehyde, was carried out under different catalytic and stoichiometric conditions. The reactions catalyzed by organocatalysts TRIP-PA and N,N'-dioxides gave the best results with respect to yields, asymmetric induction, and catalyst load in comparison to other procedures. The developed methodology was applied in the enantioselective synthesis of (5R,6S)-(+)-pteroenone, a defensive metabolite (ichthyodeterrent) of the Antarctic pteropod Clione antarctica. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Annual soil CO_{2} production in Moscow Botanical Garden (Russia).

NASA Astrophysics Data System (ADS)

Udovenko, Maria; Goncharova, Olga; Matyshak, Georgy

2017-04-01

Soil respiration is an essential component of the carbon cycle, determining 25-40 % of carbon dioxide in the atmosphere. Urban soils are subject to significant anthropogenic influences. Anthropogenic impact affects both the plants and the soil microbiota. So, soil CO2 efflux and soil profile CO2 concentration probably differ in urban and natural soils. Influence of abiotic factors on soil carbon dioxide production is explored insufficiently. The research of their impact on soil carbon dioxide production is necessary to predict soil response to anthropogenic climate change. The aim of this study was estimation of annual soil CO2 production and the impact of climatic factors on it. The research took place in Moscow State University Botanical Garden Arboretum (southern taiga). Investigations were carried out at two sites: the areas planted with Picea obovata and Carpinus betulus. The study was conducted with 1-2 weeks intervals between November 2014 and December 2015. Emission measurement were carried out by closed chamber technique, profile concentration were measured by soil air sampling tubes method. Annual carbon dioxide soil surface efflux of soil planted with Picea obovata was 1370 gCO2/(m2 * year), soil planted with Carpinus betulus - 1590 gCO2/(m2 * year). Soil CO2 concentration increased with depth in average of 3300 to 12000 ppm (at 80 cm depth). Maximum concentration values are confined to the end of vegetation period (high biological activity) and to beginning of spring (spring ice cover of soil prevents CO2 emission). Soil CO2 efflux depends on soil temperature at 10 cm depth (R = 0.89; p <0.05), in a less degree it correlate with soil surface temperature and with soil temperature at 20 cm depth (r=0.88; p<0.05). Soil moisture has a little effect on CO2 efflux in the annual cycle (r=-0.16; p<0.05). However in vegetation period efflux of carbon dioxide largely depends on soil moisture, due to the fact, that soil moisture is limiting factor for soil microbiota activity and plant respiration.

In situ spectrophotometric measurement of dissolved inorganic carbon in seawater.

PubMed

Liu, Xuewu; Byrne, Robert H; Adornato, Lori; Yates, Kimberly K; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

2013-10-01

Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

Carbon dioxide: Global warning for nephrologists

PubMed Central

Marano, Marco; D’Amato, Anna; Cantone, Alessandra

2016-01-01

The large prevalence of respiratory acid-base disorders overlapping metabolic acidosis in hemodialysis population should prompt nephrologists to deal with the partial pressure of carbon dioxide (pCO2) complying with the reduced bicarbonate concentration. What the most suitable formula to compute pCO2 is reviewed. Then, the neglected issue of CO2 content in the dialysis fluid is under the spotlight. In fact, a considerable amount of CO2 comes to patients’ bloodstream every hemodialysis treatment and “acidosis by dialysate” may occur if lungs do not properly clear away this burden of CO2. Moreover, vascular access recirculation may be easy diagnosed by detecting CO2 in the arterial line of extracorporeal circuit if CO2-enriched blood from the filter reenters arterial needle. PMID:27648406

Carbon dioxide: Global warning for nephrologists.

PubMed

Marano, Marco; D'Amato, Anna; Cantone, Alessandra

2016-09-06

The large prevalence of respiratory acid-base disorders overlapping metabolic acidosis in hemodialysis population should prompt nephrologists to deal with the partial pressure of carbon dioxide (pCO2) complying with the reduced bicarbonate concentration. What the most suitable formula to compute pCO2 is reviewed. Then, the neglected issue of CO2 content in the dialysis fluid is under the spotlight. In fact, a considerable amount of CO2 comes to patients' bloodstream every hemodialysis treatment and "acidosis by dialysate" may occur if lungs do not properly clear away this burden of CO2. Moreover, vascular access recirculation may be easy diagnosed by detecting CO2 in the arterial line of extracorporeal circuit if CO2-enriched blood from the filter reenters arterial needle.

The Application of Transcutaneous CO2 Pressure Monitoring in the Anesthesia of Obese Patients Undergoing Laparoscopic Bariatric Surgery

PubMed Central

Liu, Shijiang; Sun, Jie; Chen, Xing; Yu, Yingying; Liu, Xuan; Liu, Cunming

2014-01-01

To investigate the correlation and accuracy of transcutaneous carbon dioxide partial pressure (PTCCO2) with regard to arterial carbon dioxide partial pressure (PaCO2) in severe obese patients undergoing laparoscopic bariatric surgery. Twenty-one patients with BMI>35 kg/m2 were enrolled in our study. Their PaCO2, end-tidal carbon dioxide partial pressure (PetCO2), as well as PTCCO2 values were measured at before pneumoperitoneum and 30 min, 60 min, 120 min after pneumoperitoneum respectively. Then the differences between each pair of values (PetCO2–PaCO2) and. (PTCCO2–PaCO2) were calculated. Bland–Altman method, correlation and regression analysis, as well as exact probability method and two way contingency table were employed for the data analysis. 21 adults (aged 19–54 yr, mean 29, SD 9 yr; weight 86–160 kg, mean119.3, SD 22.1 kg; BMI 35.3–51.1 kg/m2, mean 42.1,SD 5.4 kg/m2) were finally included in this study. One patient was eliminated due to the use of vaso-excitor material phenylephrine during anesthesia induction. Eighty-four sample sets were obtained. The average PaCO2–PTCCO2 difference was 0.9±1.3 mmHg (mean±SD). And the average PaCO2–PetCO2 difference was 10.3±2.3 mmHg (mean±SD). The linear regression equation of PaCO2–PetCO2 is PetCO2 = 11.58+0.57×PaCO2 (r2 = 0.64, P<0.01), whereas the one of PaCO2–PTCCO2 is PTCCO2 = 0.60+0.97×PaCO2 (r2 = 0.89). The LOA (limits of agreement) of 95% average PaCO2–PetCO2 difference is 10.3±4.6 mmHg (mean±1.96 SD), while the LOA of 95% average PaCO2–PTCCO2 difference is 0.9±2.6 mmHg (mean±1.96 SD). In conclusion, transcutaneous carbon dioxide monitoring provides a better estimate of PaCO2 than PetCO2 in severe obese patients undergoing laparoscopic bariatric surgery. PMID:24699267

Carbon dioxide, hydrographic, and chemical data obtained in the South Pacific Ocean (WOCE Sections P16A/P17A, P17E/P19S, and P19C, R/V Knorr, October 1992--April 1993)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, S.; Goddard, J.G.; Chipman, D.W.

1998-06-01

This data documentation discusses the procedures and methods used to measure total carbon dioxide concentration (TCO{sub 2}) and partial pressure of CO{sub 2} (pCO{sub 2}) in discrete water samples collected during three expeditions of the Research Vessel (R/V) Knorr in the South Pacific Ocean. Conducted as part of the World Ocean Circulation Experiment (WOCE), the first cruise (WOCE Section P16A/P17A) began in Papeete, Tahiti, French Polynesia, on October 6, 1992, and returned to Papeete on November 25, 1992. The second cruise (WOCE Section P17E/P19S) began in Papeete on December 4, 1992, and finished in Punta Arenas, Chile, on January 22,more » 1993. The third expedition (WOCE Section P19C) started in Punta Arenas, on February 22 and finished in Panama City, Panama, on April 13, 1993. During the three expeditions, 422 hydrographic stations were occupied. Hydrographic and chemical measurements made along WOCE Sections P16A/P17A, P17E/P19S, and P19C included pressure, temperature, salinity, and oxygen [measured by conductivity, temperature, and depth (CTD) sensor], as well as discrete measurements of salinity, oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO{sub 2}, and pCO{sub 2} measured at 4 and 20 C. In addition, potential temperatures were calculated from the measured variables.« less

Intraspecific variation in juvenile tree growth under elevated CO2 alone and with O3: a meta-analysis.

PubMed

Resco de Dios, Víctor; Mereed, Tessema E; Ferrio, Juan Pedro; Tissue, David T; Voltas, Jordi

2016-06-01

Atmospheric carbon dioxide (CO2) concentrations are expected to increase throughout this century, potentially fostering tree growth. A wealth of studies have examined the variation in CO2 responses across tree species, but the extent of intraspecific variation in response to elevated CO2 (eCO2) has, so far, been examined in individual studies and syntheses of published work are currently lacking. We conducted a meta-analysis on the effects of eCO2 on tree growth (height, stem biomass and stem volume) and photosynthesis across genotypes to examine whether there is genetic variation in growth responses to eCO2 and to understand their dependence on photosynthesis. We additionally examined the interaction between the responses to eCO2 and ozone (O3), another global change agent. Most of the published studies so far have been conducted in juveniles and in Populus spp., although the patterns observed were not species dependent. All but one study reported significant genetic variation in stem biomass, and the magnitude of intraspecific variation in response to eCO2 was similar in magnitude to previous analyses on interspecific variation. Growth at eCO2 was predictable from growth at ambient CO2 (R(2) = 0.60), and relative rankings of genotype performance were preserved across CO2 levels, indicating no significant interaction between genotypic and environmental effects. The growth response to eCO2 was not correlated with the response of photosynthesis (P > 0.1), and while we observed 57.7% average increases in leaf photosynthesis, stem biomass and volume increased by 36 and 38.5%, respectively, and height only increased by 9.5%, suggesting a predominant role for carbon allocation in ultimately driving the response to eCO2 Finally, best-performing genotypes under eCO2 also responded better under eCO2 and elevated O3 Further research needs include widening the study of intraspecific variation beyond the genus Populus and examining the interaction between eCO2 and other environmental stressors. We conclude that significant potential to foster CO2-induced productivity gains through tree breeding exists, that these programs could be based upon best-performing genotypes under ambient conditions and that they would benefit from an increased understanding on the controls of allocation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Novel Real-time Carbon Dioxide Analyzer for Health and Environmental Applications

PubMed Central

Zhao, Di; Miller, Dylan; Xian, Xiaojun; Tsow, Francis

2014-01-01

To be able to detect carbon dioxide (CO2) with high accuracy and fast response time is critical for many health and environmental applications. We report on a pocket-sized CO2 sensor for real-time analysis of end-tidal CO2, and environmental CO2. The sensor shows fast and reversible response to CO2 over a wide concentration range, covering the needs of both environmental and health applications. It is also immune to the presence of various interfering gases in ambient or expired air. Furthermore, the sensor has been used for real-time breath analysis, and the results are in good agreement with those from a commercial CO2 detector. PMID:24659857

A Novel Real-time Carbon Dioxide Analyzer for Health and Environmental Applications.

PubMed

Zhao, Di; Miller, Dylan; Xian, Xiaojun; Tsow, Francis; Forzani, Erica S

2014-05-01

To be able to detect carbon dioxide (CO 2 ) with high accuracy and fast response time is critical for many health and environmental applications. We report on a pocket-sized CO 2 sensor for real-time analysis of end-tidal CO 2, and environmental CO 2 . The sensor shows fast and reversible response to CO 2 over a wide concentration range, covering the needs of both environmental and health applications. It is also immune to the presence of various interfering gases in ambient or expired air. Furthermore, the sensor has been used for real-time breath analysis, and the results are in good agreement with those from a commercial CO 2 detector.

Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone

Treesearch

Kurt Pregitzer; Wendy Loya; Mark Kubiske; Donald Zak

2006-01-01

The aspen free-air CO2 and O3 enrichment (FACTS II-FACE) study in Rhinelander, Wisconsin, USA, is designed to understand the mechanisms by which young northern deciduous forest ecosystems respond to elevated atmospheric carbon dioxide (CO2) and elevated tropospheric ozone (O3)...

Photosynthesis in tropical cover crop legumes influenced by irradiance, external carbon dioxide concentration and temperature

USDA-ARS?s Scientific Manuscript database

In plantation crops perennial tropical legumes are grown as understory plants, receive limited irradiance, and are subjected to elevated levels of CO2 and temperature. Independent short-term effects of photosynthetic photon flux density (PPFD), external carbon dioxide concentration [CO2] and temper...

Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated carbon dioxide

USDA-ARS?s Scientific Manuscript database

A major goal of climate change research is to understand whether and how terrestrial ecosystems can sequester more carbon to mitigate rising atmospheric carbon dioxide (CO2) levels. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric CO2 has been assumed to be a major mecha...

46 CFR 13.121 - Courses for tankerman endorsements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (open and closed). (vii) Rules of the Coast Guard governing operations in general and prevention of..., carbon dioxide (CO2), foam... X Halogenated hydrocarbons X Pressure-water spray system in special..., spray, fog, and flooding) X Foam (high, medium and low expansion) X Carbon dioxide (CO2) X X Halon X...

46 CFR 13.121 - Courses for tankerman endorsements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (open and closed). (vii) Rules of the Coast Guard governing operations in general and prevention of..., carbon dioxide (CO2), foam... X Halogenated hydrocarbons X Pressure-water spray system in special..., spray, fog, and flooding) X Foam (high, medium and low expansion) X Carbon dioxide (CO2) X X Halon X...

46 CFR 13.121 - Courses for tankerman endorsements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (open and closed). (vii) Rules of the Coast Guard governing operations in general and prevention of..., carbon dioxide (CO2), foam... X Halogenated hydrocarbons X Pressure-water spray system in special..., spray, fog, and flooding) X Foam (high, medium and low expansion) X Carbon dioxide (CO2) X X Halon X...

Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment

ERIC Educational Resources Information Center

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

2014-01-01

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…

Clinical Correlates of Carbon Dioxide Hypersensitivity in Children.

PubMed

Rappaport, Lance M; Sheerin, Christina; Carney, Dever M; Towbin, Kenneth E; Leibenluft, Ellen; Pine, Daniel S; Brotman, Melissa A; Roberson-Nay, Roxann; Hettema, John M

2017-12-01

Hypersensitivity to carbon dioxide (CO 2 )-enriched air may be a promising risk marker for anxiety disorders. Among adult and adolescent samples, heterogeneity in distress response to the CO 2 challenge task indexes 3 underlying classes of individuals, which distinguish between sustained and acute threat response as markers for internalizing disorders, broadly, and anxiety disorders, specifically. The present study examines latent classes in children's response to the CO 2 challenge task to clarify the association of CO 2 hypersensitivity with anxiety and internalizing symptomatology in childhood. Healthy children from a community twin sample (N = 538; age 9-13 years) rated anxious distress every 2 minutes while breathing air enriched to 7.5% CO 2 for 8 minutes. Latent growth mixture modeling evaluated potential classes of individuals with characteristic trajectories of distress during the task to clarify the association with internalizing disorder symptoms and related traits (e.g., anxiety sensitivity, irritability). Although all participants reported increased distress during the task, interindividual heterogeneity in distress indexed 3 underlying classes: a consistently low class ("low"), a consistently high class ("high"), and participants who demonstrated markedly increased acute distress ("acute"). Compared to the low class, the high class reported greater internalizing psychopathology, whereas membership in the acute class was associated with experiencing a panic-like event during the task. As in older individuals, 3 distinct trajectories emerged to capture interindividual heterogeneity in children's distress during the CO 2 challenge task. These classes were distinguished by clinical validators that reinforce the association of CO 2 hypersensitivity and internalizing disorder phenotypes in children. Copyright © 2017 American Academy of Child and Adolescent Psychiatry. All rights reserved.

In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loring, John S.; Schaef, Herbert T.; Turcu, Romulus VF

2012-04-25

The interaction of anhydrous supercritical CO2 (scCO2) with both kaolinite and ~1W (i.e. close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO2 molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO2 conditions is due to CO2 migration into the interlayer. Intercalated CO2 molecules are rotationally constrained and do notmore » appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO2 does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.« less

Photosynthetic fractionation of 13C and concentrations of dissolved CO2 in the central equatorial Pacific during the last 255,000 years

NASA Technical Reports Server (NTRS)

Jasper, J. P.; Hayes, J. M.; Mix, A. C.; Prahl, F. G.

1994-01-01

Carbon isotopically based estimates of CO2 levels have been generated from a record of the photosynthetic fractionation of 13C [is equivalent to epsilon(p)] in a central equatorial Pacific sediment core that spans the last approximately 255 ka. Contents of 13C in phytoplanktonic biomass were determined by analysis of C37 alkadienones. These compounds are exclusive products of Prymnesiophyte algae which at present grow most abundantly at depths of 70-90 m in the central equatorial Pacific. A record of the isotopic composition of dissolved CO2 was constructed from isotopic analyses of the planktonic foraminifera Neogloboquadrina dutertrei, which calcifies at 70-90 m in the same region. Values of epsilon(p), derived by comparison of the organic and inorganic delta values, were transformed to yield concentrations of dissolved CO2 [is equivalent to c(e)] based on a new, site-specific calibration of the relationship between epsilon(p) and c(e). The calibration was based on reassessment of existing epsilon(p) versus c(e) data, which support a physiologically based model in which epsilon(p) is inversely related to c(e). Values of PCO2, the partial pressure of CO2 that would be in equilibrium with the estimated concentrations of dissolved CO2, were calculated using Henry's law and the temperature determined from the alkenone-unsaturation index U(K/37). Uncertainties in these values arise mainly from uncertainties about the appropriateness (particularly over time) of the site-specific relationship between epsilon(p) and 1/c(e). These are discussed in detail and it is concluded that the observed record of epsilon(p) most probably reflects significant variations in delta pCO2, the ocean-atmosphere disequilibrium, which appears to have ranged from approximately 110 microatmospheres during glacial intervals (ocean > atmosphere) to approximately 60 microatmospheres during interglacials. Fluxes of CO2 to the atmosphere would thus have been significantly larger during glacial intervals. If this were characteristic of large areas of the equatorial Pacific, then greater glacial sinks for the equatorially evaded CO2 must have existed elsewhere. Statistical analysis of air-sea pCO2 differences and other parameters revealed significant (p<0.01) inverse correlations of delta pCO2 with sea surface temperature and with the mass accumulation rate of opal. The former suggests response to the strength of upwelling, the latter may indicate either drawdown of CO2 by siliceous phytoplankton or variation of [CO2]/[Si(OH)4] ratios in upwelling waters.

Pulsed TEA CO2 Laser Irradiation of Titanium in Nitrogen and Carbon Dioxide Gases

NASA Astrophysics Data System (ADS)

Ciganovic, J.; Matavulj, P.; Trtica, M.; Stasic, J.; Savovic, J.; Zivkovic, S.; Momcilovic, M.

2017-12-01

Surface changes created by interaction of transversely excited atmospheric carbon dioxide (TEA CO2) laser with titanium target/implant in nitrogen and carbon dioxide gas were studied. TEA CO2 laser operated at 10.6 μm, pulse length of 100 ns and fluence of ˜17 J/cm2 which was sufficient for inducing surface modifications. Induced changes depend on the gas used. In both gases the grain structure was produced (central irradiated zone) but its forms were diverse, (N2: irregular shape; CO2: hill-like forms). Hydrodynamic features at peripheral zone, like resolidified droplets, were recorded only in CO2 gas. Elemental analysis of the titanium target surface indicated that under a nitrogen atmosphere surface nitridation occurred. In addition, irradiation in both gases was followed by appearance of plasma in front of the target. The existence of plasma indicates relatively high temperatures created above the target surface offering a sterilizing effect.

Technical and economic evaluation of biogas capture and treatment for the Piedras Blancas landfill in Córdoba, Argentina.

PubMed

Francisca, Franco Matías; Montoro, Marcos Alexis; Glatstein, Daniel Alejandro

2017-05-01

Landfill gas (LFG) management is one of the most important tasks for landfill operation and closure because of its impact in potential global warming. The aim of this work is to present a case history evaluating an LFG capture and treatment system for the present landfill facility in Córdoba, Argentina. The results may be relevant for many developing countries around the world where landfill gas is not being properly managed. The LFG generation is evaluated by modeling gas production applying the zero-order model, Landfill Gas Emissions Model (LandGEM; U.S. Environmental Protection Agency [EPA]), Scholl Canyon model, and triangular model. Variability in waste properties, weather, and landfill management conditions are analyzed in order to evaluate the feasibility of implementing different treatment systems. The results show the advantages of capturing and treating LFG in order to reduce the emissions of gases responsible for global warming and to determine the revenue rate needed for the project's financial requirements. This particular project reduces by half the emission of equivalent tons of carbon dioxide (CO 2 ) compared with the situation where there is no gas treatment. In addition, the study highlights the need for a change in the electricity prices if it is to be economically feasible to implement the project in the current Argentinean electrical market. Methane has 21 times more greenhouse gas potential than carbon dioxide. Because of that, it is of great importance to adequately manage biogas emissions from landfills. In addition, it is environmentally convenient to use this product as an alternative energy source, since it prevents methane emissions while preventing fossil fuel consumption, minimizing carbon dioxide emissions. Performed analysis indicated that biogas capturing and energy generation implies 3 times less equivalent carbon dioxide emissions; however, a change in the Argentinean electrical market fees are required to guarantee the financial feasibility of the project.

Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities.

PubMed

Müller, R Dietmar; Dutkiewicz, Adriana

2018-02-01

Atmospheric carbon dioxide (CO 2 ) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. The vast oceanic crustal carbon reservoir is an alternative potential driving force of climate fluctuations at these time scales, with hydrothermal crustal carbon uptake occurring mostly in young crust with a strong dependence on ocean bottom water temperature. We combine a global plate model and oceanic paleo-age grids with estimates of paleo-ocean bottom water temperatures to track the evolution of the oceanic crustal carbon reservoir over the past 230 My. We show that seafloor spreading rates as well as the storage, subduction, and emission of oceanic crustal and mantle CO 2 fluctuate with a period of 26 My. A connection with seafloor spreading rates and equivalent cycles in subduction zone rollback suggests that these periodicities are driven by the dynamics of subduction zone migration. The oceanic crust-mantle carbon cycle is thus a previously overlooked mechanism that connects plate tectonic pulsing with fluctuations in atmospheric carbon and surface environments.

Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities

PubMed Central

Müller, R. Dietmar; Dutkiewicz, Adriana

2018-01-01

Atmospheric carbon dioxide (CO2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. The vast oceanic crustal carbon reservoir is an alternative potential driving force of climate fluctuations at these time scales, with hydrothermal crustal carbon uptake occurring mostly in young crust with a strong dependence on ocean bottom water temperature. We combine a global plate model and oceanic paleo-age grids with estimates of paleo-ocean bottom water temperatures to track the evolution of the oceanic crustal carbon reservoir over the past 230 My. We show that seafloor spreading rates as well as the storage, subduction, and emission of oceanic crustal and mantle CO2 fluctuate with a period of 26 My. A connection with seafloor spreading rates and equivalent cycles in subduction zone rollback suggests that these periodicities are driven by the dynamics of subduction zone migration. The oceanic crust-mantle carbon cycle is thus a previously overlooked mechanism that connects plate tectonic pulsing with fluctuations in atmospheric carbon and surface environments. PMID:29457135

Effects of elevated temperature and CO2 concentration on photosynthesis of the alpine plants in Zoige Plateau, China

NASA Astrophysics Data System (ADS)

Zijuan, Zhou; Peixi, Su; Rui, Shi; Tingting, Xie

2017-04-01

Increasing temperature and carbon dioxide concentration are the important aspects of global climate change. Alpine ecosystem response to global change was more sensitive and rapid than other ecosystems. Increases in temperature and atmospheric CO2concentrations have strong impacts on plant physiology. Photosynthesis is the basis for plant growth and the decisive factor for the level of productivity, and also is a very sensitive physiological process to climate change. In this study, we examined the interactive effects of elevated temperature and atmospheric CO2 concentration on the light response of photosynthesis in two alpine plants Elymus nutans and Potentilla anserine, which were widely distributed in alpine meadow in the Zoige Plateau, China. We set up as follows: the control (Ta 20˚ C, CO2 380μmolṡmol-1), elevated temperature (Ta 25˚ C, CO2 380 μmolṡmol-1), elevated CO2 concentration (Ta 20˚ C, CO2 700μmolṡmol-1), elevated temperature and CO2 concentration (Ta 25˚ C, CO2 700μmolṡmol-1). The results showed that compared to P. anserine, E. nutans had a higher maximum net photosynthetic rate (Pnmax), light saturation point (LSP) and apparent quantum yield (AQY) in the control. Elevated temperature increased the Pnmaxand LSP values in P. anserine, while Pnmaxand LSP were decreased in E. nutans. Elevated CO2 increased the Pnmaxand LSP values in E. nutans and P. anserine, while the light compensation point (LCP) decreased; Elevated both temperature and CO2, the Pnmaxand LSP were all increased for E. nutans and P. anserine, but did not significantly affect AQY. We concluded that although elevated temperature had a photoinhibition for E. nutans, the interaction of short-term elevated CO2 concentration and temperature can improve the photosynthetic capacity of alpine plants. Key Words: elevated temperature; CO2 concentration; light response; alpine plants

Temporal Trends of NO2, CO and their Relation to the Fire Occurrences over the Indo-Gangetic Plain

NASA Astrophysics Data System (ADS)

Pandey, A. K.; Kumar, K.

2016-12-01

Air pollution is an environmental issue that has a gigantic impact on human health, and it is a major problem in the densely populated regions throughout the world. Situated in the foothills of the great Himalayas Indo-Gangetic Plain (IGP) is among one of the most densely populated regions of the earth. NO2 and CO are among major air pollutants which affect the air quality of IGP predominantly. In the present study, we studied the temporal trends of NO2, CO and fire count over the IGP region. Further, we investigated the role of the fire occurrences in the ambient NO2 and CO levels. We used MODIS instrument (Aqua satellite), OMI sensor and AIRS instrument data for fire count, Nitrogen Dioxide (NO2) tropospheric column and Carbon monoxide (CO) column study respectively. The IGP is divided into three part geographically i.e. Eastern (E-IGP), Central (C-IGP) and Western (W-IGP). A higher columnar CO concentration is observed in the E-IGP whereas NO2 concentration is highest in the W-IGP. A higher NO2 concentration is obtained in winter followed by summer and a minimum in monsoon months throughout the IGP. Columnar CO concentration is higher in the E-IGP and its concentration is maximum in pre-monsoon months and minimum in the monsoon months. Fire pixel count is highest in the W-IGP with peak twice every year i.e. in the April - May and October - November corresponding to the harvest period in the Rabi-Kharif cropping system. We also obtained a significant positive correlation between fire occurrences and columnar NO2 & CO levels over the IGP which shows the biomass burning practices associated with the agriculture influences the NO2 and CO concentration in the atmosphere.

Supercritical Carbon Dioxide Extraction of Selected Herbal Leaves: An Overview

NASA Astrophysics Data System (ADS)

Hamid, I. A. Abd; Ismail, N.; Rahman, N. Abd

2018-05-01

Supercritical fluid extraction of carbon dioxide (SC-CO2) is one of new alternative extraction method that has been widely used to isolate bioactive components from variety of plant materials. The method was proved to be clean and safe, compatible for the extraction of edible products such as spices, food additives, medicines and nutritional supplement products compared to traditional extraction techniques such as solvent extraction, hydro distillation and steam distillation. The SC-CO2 extraction was known as highly influenced by its process parameter such as temperature and pressure for obtaining maximum yield. Therefore, a clear review on the optimum range of temperature and pressure for herbal leaves extraction using SC-CO2 is necessary for future reference. The aim of this work is to analyze the effect of temperature and pressure of SC-CO2 process without modifier on extraction yield of some selected herbal leaves i.e clubmoss, drumstick leaves, kratom leaves, mallee and myrtle leaves. The values of investigated parameters were; pressure from 8.9 to 50 MPa and temperature from 35 to 80°C. The results showed that the highest extraction yields were obtained when the pressure and temperature were above 30 MPa and 40°C. The interaction between pressure and temperature for SC-CO2 extraction of plant leaves are crucial since the values cannot be very high or very low in order to preserve the quality of the extracts.

On kinetic modelling for solar redox thermochemical H2O and CO2 splitting over NiFe2O4 for H2, CO and syngas production.

PubMed

Dimitrakis, Dimitrios A; Syrigou, Maria; Lorentzou, Souzana; Kostoglou, Margaritis; Konstandopoulos, Athanasios G

2017-10-11

This study aims at developing a kinetic model that can adequately describe solar thermochemical water and carbon dioxide splitting with nickel ferrite powder as the active redox material. The kinetic parameters of water splitting of a previous study are revised to include transition times and new kinetic parameters for carbon dioxide splitting are developed. The computational results show a satisfactory agreement with experimental data and continuous multicycle operation under varying operating conditions is simulated. Different test cases are explored in order to improve the product yield. At first a parametric analysis is conducted, investigating the appropriate duration of the oxidation and the thermal reduction step that maximizes the hydrogen yield. Subsequently, a non-isothermal oxidation step is simulated and proven as an interesting option for increasing the hydrogen production. The kinetic model is adapted to simulate the production yields in structured solar reactor components, i.e. extruded monolithic structures, as well.

Effects of long-term (10 years) exposure to elevated CO2 and O3 on trembling Aspen carbon and nitrogen metabolism at the aspen FACE (Free-Air Carbon Dioxide Enrichment) study site

Treesearch

Rakesh Minocha; Stephanie Long; Subhash Minocha; Paula Marquardt; Neil Nelson; Mark. Kubiske

2010-01-01

This study was conducted at the Aspen Free-Air Carbon Dioxide Enrichment (FACE) experimental site, Rhinelander, WI, (USA). Since 1998, 12 experimental rings planted in 1997 underwent four different treatments: control; elevated CO2 (560 ppm); elevated O3 (1.5X ambient) and elevated CO2 (560 ppm) + O...

Somewhere beyond the sea? The oceanic - carbon dioxide - reactions

NASA Astrophysics Data System (ADS)

Meisinger, Philipp; Wittlich, Christian

2014-05-01

In correlation to climate change and CO2 emission different campaigns highlight the importance of forests and trees to regulate the concentration of carbon dioxide in the earths' atmosphere. Seeing millions of square miles of rainforest cut down every day, this is truly a valid point. Nevertheless, we often tend to forget what scientists like Spokes try to raise awareness for: The oceans - and foremost deep sea sections - resemble the second biggest deposit of carbon dioxide. Here carbon is mainly found in form of carbonate and hydrogen carbonate. The carbonates are needed by corals and other sea organisms to maintain their skeletal structure and thereby to remain vital. To raise awareness for the protection of this fragile ecosystem in schools is part of our approach. Awareness is achieved best through understanding. Therefore, our approach is a hands-on activity that aims at showing students how the carbon dioxide absorption changes in relation to the water temperature - in times of global warming a truly sensitive topic. The students use standard syringes filled with water (25 ml) at different temperatures (i.e. 10°C, 20°C, 40°C). Through a connector students inject carbon dioxide (25ml) into the different samples. After a fixed period of time, students can read of the remaining amount of carbon dioxide in relation to the given water temperature. Just as with every scientific project, students need to closely monitor their experiments and alter their setups (e.g. water temperature or acidity) according to their initial planning. A digital template (Excel-based) supports the analysis of students' experiments. Overview: What: hands-on, minds -on activity using standard syringes to exemplify carbon dioxide absorption in relation to the water temperature (Le Chatelier's principle) For whom: adjustable from German form 11-13 (age: 16-19 years) Time: depending on the prior knowledge 45-60 min. Sources (extract): Spokes, L.: Wie Ozeane CO2 aufnehmen. Environmental Sciences. University of East Anglia, Norwich 2007. Von Borstel, G. und Böhm, A.: Le Chatelier einmal anders, Gleichgewichtsverschiebungen am Kontext Sprudelwasser. Naturwissenschaft im Unterricht Chemie 6 (2006) H. 96, S. 34-37

Implications of High Temperature and Elevated CO2 on Flowering Time in Plants

PubMed Central

Jagadish, S. V. Krishna; Bahuguna, Rajeev N.; Djanaguiraman, Maduraimuthu; Gamuyao, Rico; Prasad, P. V. Vara; Craufurd, Peter Q.

2016-01-01

Flowering is a crucial determinant for plant reproductive success and seed-set. Increasing temperature and elevated carbon-dioxide (e[CO2]) are key climate change factors that could affect plant fitness and flowering related events. Addressing the effect of these environmental factors on flowering events such as time of day of anthesis (TOA) and flowering time (duration from germination till flowering) is critical to understand the adaptation of plants/crops to changing climate and is the major aim of this review. Increasing ambient temperature is the major climatic factor that advances flowering time in crops and other plants, with a modest effect of e[CO2].Integrated environmental stimuli such as photoperiod, temperature and e[CO2] regulating flowering time is discussed. The critical role of plant tissue temperature influencing TOA is highlighted and crop models need to substitute ambient air temperature with canopy or floral tissue temperature to improve predictions. A complex signaling network of flowering regulation with change in ambient temperature involving different transcription factors (PIF4, PIF5), flowering suppressors (HvODDSOC2, SVP, FLC) and autonomous pathway (FCA, FVE) genes, mainly from Arabidopsis, provides a promising avenue to improve our understanding of the dynamics of flowering time under changing climate. Elevated CO2 mediated changes in tissue sugar status and a direct [CO2]-driven regulatory pathway involving a key flowering gene, MOTHER OF FT AND TFL1 (MFT), are emerging evidence for the role of e[CO2] in flowering time regulation. PMID:27446143

Effect of Ocean Acidification on the Food Quality of the Coccolithophore Emiliania huxleyi

NASA Astrophysics Data System (ADS)

Maine, J. E.; White, M. M.; Balch, W. M.; Milke, L. M.

2016-02-01

The anthropogenic burning of fossil fuels has doubled atmospheric carbon dioxide (CO2) levels over the last 200 years. Atmospheric CO2 diffuses into the ocean, changing the chemistry and decreasing the pH of seawater in a process called Ocean Acidification (OA). Calcifying marine phytoplankton, coccolithophores, are vulnerable to OA. Emiliania huxleyi is a lipid-dense and globally-abundant species of coccolithophore, therefore it is a vital food source for higher marine trophic levels. The objective of this project was to determine how OA affects the lipid profile and calcification of E. huxleyi CCMP #371. Gas chromatography was used to determine how the proportions of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) in E. huxleyi varied with increasing pCO2. Flow cytometry was used to measure how the distribution of highly calcified cells, partially calcified cells, and un-calcified cells changed with increasing pCO2. The proportion of MUFA increased with pCO2. The proportion of un-calcified and partially calcified cells increased with increasing pCO2, however, the results varied across two experimental runs. In conclusion, the lipid-profile and calcification properties of E. huxleyi, and likely its food quality to predators, are affected by OA.

76 FR 49391 - Approval, Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; Smoke...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-10

..., Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; Smoke, Opacity and Sulfur Dioxide... opacity, particulate, sulfur dioxide (SO 2 ), and carbon monoxide (CO) emissions from sources. EPA has... mean Nitrogen Dioxide and SO2 mean Sulfur Dioxide. (vii) The initials BACT mean Best Available Control...

Carbon footprint and ammonia emissions of California beef production systems.

PubMed

Stackhouse-Lawson, K R; Rotz, C A; Oltjen, J W; Mitloehner, F M

2012-12-01

Beef production is a recognized source of greenhouse gas (GHG) and ammonia (NH(3)) emissions; however, little information exists on the net emissions from beef production systems. A partial life cycle assessment (LCA) was conducted using the Integrated Farm System Model (IFSM) to estimate GHG and NH(3) emissions from representative beef production systems in California. The IFSM is a process-level farm model that simulates crop growth, feed production and use, animal growth, and the return of manure nutrients back to the land to predict the environmental impacts and economics of production systems. Ammonia emissions are determined by summing the emissions from animal housing facilities, manure storage, field applied manure, and direct deposits of manure on pasture and rangeland. All important sources and sinks of methane, nitrous oxide, and carbon dioxide are predicted from primary and secondary emission sources. Primary sources include enteric fermentation, manure, cropland used in feed production, and fuel combustion. Secondary emissions occur during the production of resources used on the farm, which include fuel, electricity, machinery, fertilizer, and purchased animals. The carbon footprint is the net exchange of all GHG in carbon dioxide equivalent (CO(2)e) units per kg of HCW produced. Simulated beef production systems included cow-calf, stocker, and feedlot phases for the traditional British beef breeds and calf ranch and feedlot phases for Holstein steers. An evaluation of differing production management strategies resulted in ammonia emissions ranging from 98 ± 13 to 141 ± 27 g/kg HCW and carbon footprints of 10.7 ± 1.4 to 22.6 ± 2.0 kg CO(2)e/kg HCW. Within the British beef production cycle, the cow-calf phase was responsible for 69 to 72% of total GHG emissions with 17 to 27% from feedlot sources. Holstein steers that entered the beef production system as a by-product of dairy production had the lowest carbon footprint because the emissions associated with their mothers were primarily attributed to milk rather than meat production. For the Holstein system, the feedlot phase was responsible for 91% of the total GHG emission, while the calf-ranch phase was responsible for 7% with the remaining 2% from transportation. This simulation study provides baseline emissions data for California beef production systems and indicates where mitigation strategies can be most effective in reducing emissions.

Measurements of Carbon Dioxide, Methane, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

NASA Astrophysics Data System (ADS)

Forgeron, J.; Yasuhara, S.; Rella, C.; Jacobson, G. A.; Chiao, S.

2012-12-01

Measurements of Carbon Dioxide, Methane, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment Jeff Forgeron1,2, Scott Yasuhara1,2, Chris Rella1, Gloria Jacobson1, Sen Chiao2 1Picarro Inc., 3105 Patrick Henry Drive, Santa Clara California 95054 USA 2San Jose State University, 1 Washington Square, San Jose California USA JeffAForgeron@gmail.com The ability to quantify sources and sinks of carbon dioxide and methane on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to 'bottom-up' predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has proven to be effective at continental scales, becomes challenging to implement at urban scales, due to poorly understood atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, green spaces) and time (rush hours, factory shifts and shutdowns, and diurnal and seasonal variation in residential energy use). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal- resolution greenhouse gas measurements made by multiple Picarro-CRDS analyzers in Silicon Valley in California. Real-time carbon dioxide data from a 12-month period are combined with real-time carbon monoxide, methane, acetylene, and carbon-13 measurements to partition the observed carbon dioxide concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. Real-time wind rose data are also combined with real-time methane data to help identify the direction of local emissions of methane. The ratio between carbon dioxide and carbon monoxide is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid but frequent shifts in the balance between different carbon dioxide sources. Additional information is given by the carbon-13 signature and by acetylene, a fossil fuel combustion tracer that provides complimentary information to carbon monoxide. In spring and summer, the combined signal of the urban center and the surrounding biosphere and urban green space is explored. These methods show great promise for identifying, quantifying, and partitioning urban-ecological (carbon) emissions. Figure 1: The left graph shows the change in diurnal cycle of CO2 (with the traffic signal removed) over a five month period. The right graph is the transit CO2 signal from weekdays and weekends, showing clear weekday enhancement of transit emissions.

Atmospheric Carbon Dioxide Record from In Situ Measurements at Mt. Cimone (1979-1997)

DOE Data Explorer

Colombo, Tiziano [Italian Meteorological Service, Sestola (MO), Italy; Santaguida, Riccardo

1998-01-01

Continuous atmospheric CO2 measurements have been carried out at Mt. Cimone since 1979. Since December 1988, air samples have also been collected approximately once per week in a pair of 2-L, electropolished, stainless steel cylindrical flasks. From 1979 until December 1988, a Hartmann and Braun URAS-2T NDIR gas analyzer was used for CO2 determinations. Currently, CO2 determinations are made through the use of a Siemens Ultramat-5E NDIR gas analyzer. Water vapor is eliminated by passing the air through a U-tube placed in an alcohol bath at -600°C. Calibration of the Ultramat-5E is accomplished by using two CO2-in-air working standard gases. These working standard gas concentrations are checked 10 days apart against three CO2-in-air mixtures that serve as secondary standards. The secondary standards are checked every 6 months against five other CO2-in-air primary standards. Hourly CO2 values are routinely plotted together with wind data. Anomalous concentrations and those affected by instrument failures or local sources are rejected. Atmospheric CO2 concentrations from Mt. Cimone are reported in the 1993 WMO/Scripps mole fraction scale. For further details on the measurement apparatus and sampling techniques used at Mt. Cimone, see Cundari et al. (1990).

Kinetic bottlenecks to chemical exchange rates for deep-sea animals - Part 2: Carbon Dioxide

NASA Astrophysics Data System (ADS)

Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

2013-04-01

Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc.) as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

Long-Duration Carbon Dioxide Anesthesia of Fish Using Ultra Fine (Nano-Scale) Bubbles.

PubMed

Kugino, Kenji; Tamaru, Shizuka; Hisatomi, Yuko; Sakaguchi, Tadashi

2016-01-01

We investigated whether adding ultrafine (nano-scale) oxygen-carrying bubbles to water concurrently with dissolved carbon-dioxide (CO2) could result in safe, long-duration anesthesia for fish. To confirm the lethal effects of CO2 alone, fishes were anesthetized with dissolved CO2 in 20°C seawater. Within 30 minutes, all fishes, regardless of species, died suddenly due to CO2-induced narcosis, even when the water was saturated with oxygen. Death was attributed to respiration failure caused by hypoxemia. When ultrafine oxygen-carrying bubbles were supplied along with dissolved CO2, five chicken grunts were able to remain anesthetized for 22 hours and awoke normally within 2-3 hours after cessation of anesthesia. The high internal pressures and oxygen levels of the ultrafine bubbles enabled efficient oxygen diffusion across the branchia and permitted the organismal oxygen demands of individual anesthetized fish to be met. Thus, we demonstrated a method for safe, long-duration carbon dioxide anesthesia in living fish under normal water temperatures.

Sequestering CO(2) by mineral carbonation: stability against acid rain exposure.

PubMed

Allen, Daniel J; Brent, Geoff F

2010-04-01

Mineral carbonation is a potentially attractive alternative to storage of compressed CO(2) in underground repositories, known as geosequestration. Processes for the conversion of basic ores, such as magnesium silicates, to carbonates have been proposed by various researchers, with storage of the carbonate as backfill in the original mine representing a solid carbon sink. The stability of such carbon sinks against acid rain and other sources of strong acids is examined here. It is acknowledged that in the presence of strong acid, carbonates will dissolve and release carbon dioxide. A sensitivity analysis covering annual average rainfall and pH that may be encountered in industrialized areas of the United States, China, Europe, and Australia was conducted to determine maximum CO(2) rerelease rates from mineral carbonation carbon sinks. This analysis is based on a worst-case premise that is equivalent to assuming infinitely rapid kinetics of dissolution of the carbonate. The analysis shows that under any likely conditions of pH and rainfall, leakage rates of stored CO(2) are negligible. This is illustrated in a hypothetical case study under Australian conditions. It is thus proposed that sequestration by mineral carbonation can be considered to be permanent on practical human time scales. Other possible sources of acid have also been considered.

Potential Cost-Effective Opportunities for Methane Emission Abatement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warner, Ethan; Steinberg, Daniel; Hodson, Elke

2015-08-01

The energy sector was responsible for approximately 84% of carbon dioxide equivalent (CO 2e) greenhouse gas (GHG) emissions in the U.S. in 2012 (EPA 2014a). Methane is the second most important GHG, contributing 9% of total U.S. CO 2e emissions. A large portion of those methane emissions result from energy production and use; the natural gas, coal, and oil industries produce approximately 39% of anthropogenic methane emissions in the U.S. As a result, fossil-fuel systems have been consistently identified as high priority sectors to contribute to U.S. GHG reduction goals (White House 2015). Only two studies have recently attempted tomore » quantify the abatement potential and cost associated with the breadth of opportunities to reduce GHG emissions within natural gas, oil, and coal supply chains in the United States, namely the U.S. Environmental Protection Agency (EPA) (2013a) and ICF (2014). EPA, in its 2013 analysis, estimated the marginal cost of abatement for non-CO 2 GHG emissions from the natural gas, oil, and coal supply chains for multiple regions globally, including the United States. Building on this work, ICF International (ICF) (2014) provided an update and re-analysis of the potential opportunities in U.S. natural gas and oil systems. In this report we synthesize these previously published estimates as well as incorporate additional data provided by ICF to provide a comprehensive national analysis of methane abatement opportunities and their associated costs across the natural gas, oil, and coal supply chains. Results are presented as a suite of marginal abatement cost curves (MACCs), which depict the total potential and cost of reducing emissions through different abatement measures. We report results by sector (natural gas, oil, and coal) and by supply chain segment - production, gathering and boosting, processing, transmission and storage, or distribution - to facilitate identification of which sectors and supply chain segments provide the greatest opportunities for low cost abatement.« less

Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) Aircraft Measurements of CO2

NASA Technical Reports Server (NTRS)

Christensen, Lance E.; Spiers, Gary D.; Menzies, Robert T.; Jacob, Joseph C.; Hyon, Jason

2011-01-01

The Jet Propulsion Laboratory Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) utilizes Integrated Path Differential Absorption (IPDA) at 2.05 microns to obtain CO2 column mixing ratios weighted heavily in the boundary layer. CO2LAS employs a coherent detection receiver and continuous-wave Th:Ho:YLF laser transmitters with output powers around 100 milliwatts. An offset frequency-locking scheme coupled to an absolute frequency reference enables the frequencies of the online and offline lasers to be held to within 200 kHz of desired values. We describe results from 2009 field campaigns when CO2LAS flew on the Twin Otter. We also describe spectroscopic studies aimed at uncovering potential biases in lidar CO2 retrievals at 2.05 microns.

Chemical microenvironments and single-cell carbon and nitrogen uptake in field-collected colonies of Trichodesmium under different pCO2

PubMed Central

Eichner, Meri J; Klawonn, Isabell; Wilson, Samuel T; Littmann, Sten; Whitehouse, Martin J; Church, Matthew J; Kuypers, Marcel MM; Karl, David M; Ploug, Helle

2017-01-01

Gradients of oxygen (O2) and pH, as well as small-scale fluxes of carbon (C), nitrogen (N) and O2 were investigated under different partial pressures of carbon dioxide (pCO2) in field-collected colonies of the marine dinitrogen (N2)-fixing cyanobacterium Trichodesmium. Microsensor measurements indicated that cells within colonies experienced large fluctuations in O2, pH and CO2 concentrations over a day–night cycle. O2 concentrations varied with light intensity and time of day, yet colonies exposed to light were supersaturated with O2 (up to ~200%) throughout the light period and anoxia was not detected. Alternating between light and dark conditions caused a variation in pH levels by on average 0.5 units (equivalent to 15 nmol l−1 proton concentration). Single-cell analyses of C and N assimilation using secondary ion mass spectrometry (SIMS; large geometry SIMS and nanoscale SIMS) revealed high variability in metabolic activity of single cells and trichomes of Trichodesmium, and indicated transfer of C and N to colony-associated non-photosynthetic bacteria. Neither O2 fluxes nor C fixation by Trichodesmium were significantly influenced by short-term incubations under different pCO2 levels, whereas N2 fixation increased with increasing pCO2. The large range of metabolic rates observed at the single-cell level may reflect a response by colony-forming microbial populations to highly variable microenvironments. PMID:28398346

A short-term carbon dioxide treatment inhibits the browning of fresh-cut burdock

USDA-ARS?s Scientific Manuscript database

Fresh-cut burdock is susceptible to browning. The effect of short term carbon dioxide (CO2) treatment on inhibiting browning of fresh-cut burdock during storage at 2~4' was investigated. The results showed that the burdock slices treated with CO2 for 4 h, 6 h and 8 h exhibited better visual quality ...

Fischer-Tropsch synthesis in supercritical phase carbon dioxide: Recycle rates

NASA Astrophysics Data System (ADS)

Soti, Madhav

With increasing oil prices and attention towards the reduction of anthropogenic CO2, the use of supercritical carbon dioxide for Fischer Tropsch Synthesis (FTS) is showing promise in fulfilling the demand of clean liquid fuels. The evidence of consumption of carbon dioxide means that it need not to be removed from the syngas feed to the Fischer Tropsch reactor after the gasification process. Over the last five years, research at SIUC have shown that FTS in supercritical CO2reduces the selectivities for methane, enhances conversion, reduces the net CO2produces in the coal to liquid fuels process and increase the life of the catalyst. The research has already evaluated the impact of various operating and feed conditions on the FTS for the once through process. We believe that the integration of unreacted feed recycle would enhance conversion, increase the yield and throughput of liquid fuels for the same reactor size. The proposed research aims at evaluating the impact of recycle of the unreacted feed gas along with associated product gases on the performance of supercritical CO2FTS. The previously identified conditions will be utilized and various recycle ratios will be evaluated in this research once the recycle pump and associated fittings have been integrated to the supercritical CO2FTS. In this research two different catalysts (Fe-Zn-K, Fe-Co-Zn-K) were analyzed under SC-FTS in different recycle rate at 350oC and 1200 psi. The use of recycle was found to improve conversion from 80% to close to 100% with both catalysts. The experiment recycle rate at 4.32 and 4.91 was clearly surpassing theoretical recycle curve. The steady state reaction rate constant was increased to 0.65 and 0.8 min-1 for recycle rate of 4.32 and 4.91 respectively. Carbon dioxide selectivity was decreased for both catalyst as it was converting to carbon monoxide. Carbon dioxide consumption was increased from 0.014 to 0.034 mole fraction. This concluded that CO2is being used in the system and converting which created the concentration of the feed gas higher inside the reactor. The research has provided the best conditions for the enhanced conversion while minimizing CO2formation. Though this research was not able to provide the optimal recycle rate it have created the path for the future research to proceed in the right direction. This reduction and utilization of CO2will help to reduce the cost of carbon dioxide removal and saves the environment from carbon dioxide emission.

Hydride Conformers of the Nitrogenase FeMo-cofactor Two-Electron Reduced State E2(2H), Assigned Using Cryogenic Intra Electron Paramagnetic Resonance Cavity Photolysis.

PubMed

Lukoyanov, Dmitriy A; Khadka, Nimesh; Yang, Zhi-Yong; Dean, Dennis R; Seefeldt, Lance C; Hoffman, Brian M

2018-03-24

Early studies in which nitrogenase was freeze-trapped during enzymatic turnover revealed the presence of high-spin ( S = 3 / 2 ) electron paramagnetic resonance (EPR) signals from the active-site FeMo-cofactor (FeMo-co) in electron-reduced intermediates of the MoFe protein. Historically denoted as 1b and 1c, each of the signals is describable as a fictitious spin system, S' = 1 / 2 , with anisotropic g' tensor, 1b with g' = [4.21, 3.76, ?] and 1c with g' = [4.69, ∼3.20, ?]. A clear discrepancy between the magnetic properties of 1b and 1c and the kinetic analysis of their appearance during pre-steady-state turnover left their identities in doubt, however. We subsequently associated 1b with the state having accumulated 2[e - /H + ], denoted as E 2 (2H), and suggested that the reducing equivalents are stored on the catalytic FeMo-co cluster as an iron hydride, likely an [Fe-H-Fe] hydride bridge. Intra-EPR cavity photolysis (450 nm; temperature-independent from 4 to 12 K) of the E 2 (2H)/1b state now corroborates the identification of this state as storing two reducing equivalents as a hydride. Photolysis converts E 2 (2H)/1b to a state with the same EPR spectrum, and thus the same cofactor structure as pre-steady-state turnover 1c, but with a different active-site environment. Upon annealing of the photogenerated state at temperature T = 145 K, it relaxes back to E 2 (2H)/1b. This implies that the 1c signal comes from an E 2 (2H) hydride isomer of E 2 (2H)/1b that stores its two reducing equivalents either as a hydride bridge between a different pair of iron atoms or an Fe-H terminal hydride.

Carbon dioxide-dependent regulation of NF-κB family members RelB and p100 gives molecular insight into CO2-dependent immune regulation.

PubMed

Keogh, Ciara E; Scholz, Carsten C; Rodriguez, Javier; Selfridge, Andrew C; von Kriegsheim, Alexander; Cummins, Eoin P

2017-07-07

CO 2 is a physiological gas normally produced in the body during aerobic respiration. Hypercapnia (elevated blood pCO 2 >≈50 mm Hg) is a feature of several lung pathologies, e.g. chronic obstructive pulmonary disease. Hypercapnia is associated with increased susceptibility to bacterial infections and suppression of inflammatory signaling. The NF-κB pathway has been implicated in these effects; however, the molecular mechanisms underpinning cellular sensitivity of the NF-κB pathway to CO 2 are not fully elucidated. Here, we identify several novel CO 2 -dependent changes in the NF-κB pathway. NF-κB family members p100 and RelB translocate to the nucleus in response to CO 2 A cohort of RelB protein-protein interactions ( e.g. with Raf-1 and IκBα) are altered by CO 2 exposure, although others are maintained ( e.g. with p100). RelB is processed by CO 2 in a manner dependent on a key C-terminal domain located in its transactivation domain. Loss of the RelB transactivation domain alters NF-κB-dependent transcriptional activity, and loss of p100 alters sensitivity of RelB to CO 2 Thus, we provide molecular insight into the CO 2 sensitivity of the NF-κB pathway and implicate altered RelB/p100-dependent signaling in the CO 2 -dependent regulation of inflammatory signaling. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Seasonal variation of carbon dioxide fluxes over irrigated soybean ( Glycine max L.)

NASA Astrophysics Data System (ADS)

Şaylan, Levent; Kimura, Reiji; Munkhtsetseg, Erdenebayar; Kamichika, Makio

2011-08-01

In this study, variations in carbon dioxide (CO2) fluxes resulting from gross primary production (GPP), net ecosystem exchange (NEE), and respiration ( R e) of soybean ( Glycine max L.) were investigated by the Eddy Covariance method during the growing period from June to November 2005 on an irrigated sand field at the Arid Land Research Center, Tottori University in Tottori, Japan. Although climatic conditions were humid and temperate, the soybeans required frequent irrigation because of the low water holding capacity of the sandy soil at the field site. Finally, it has been found that the accumulated NEE, GPP, and R e fluxes of soybean over 126 days amount to -93, 319, and 226 gC m-2, respectively. Furthermore, the average ratio of GPP to R e was 1.4 and the average ratio of NEE to GPP was about -0.29 for the growth period of soybean. Daily maximum NEE of -3.8 gC m-2 occurred when LAI was 1.1.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hur, Tae-Bong; Fazio, James; Romanov, Vyacheslav

Due to increasing atmospheric CO2 concentrations causing the global energy and environmental crises, geological sequestration of carbon dioxide is now being actively considered as an attractive option to mitigate greenhouse gas emissions. One of the important strategies is to use deep unminable coal seams, for those generally contain significant quantities of coal bed methane that can be recovered by CO2 injection through enhanced coal bed natural gas production, as a method to safely store CO2. It has been well known that the adsorbing CO2 molecules introduce structural deformation, such as distortion, shrinkage, or swelling, of the adsorbent of coal organicmore » matrix. The accurate investigations of CO2 sorption capacity as well as of adsorption behavior need to be performed under the conditions that coals deform. The U.S. Department of Energy-National Energy Technology Laboratory and Regional University Alliance are conducting carbon dioxide sorption isotherm experiments by using manometric analysis method for estimation of CO2 sorption capacity of various coal samples and are constructing a gravimetric apparatus which has a visual window cell. The gravimetric apparatus improves the accuracy of carbon dioxide sorption capacity and provides feasibility for the observation of structural deformation of coal sample while carbon dioxide molecules interact with coal organic matrix. The CO2 sorption isotherm measurements have been conducted for moist and dried samples of the Central Appalachian Basin (Russell County, VA) coal seam, received from the SECARB partnership, at the temperature of 55 C.« less

Food security and climate change: on the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide

PubMed Central

Ziska, Lewis H.; Bunce, James A.; Shimono, Hiroyuki; Gealy, David R.; Baker, Jeffrey T.; Newton, Paul C. D.; Reynolds, Matthew P.; Jagadish, Krishna S. V.; Zhu, Chunwu; Howden, Mark; Wilson, Lloyd T.

2012-01-01

Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO2) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO2 to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO2 and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO2 responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change. PMID:22874755

Food security and climate change: on the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide.

PubMed

Ziska, Lewis H; Bunce, James A; Shimono, Hiroyuki; Gealy, David R; Baker, Jeffrey T; Newton, Paul C D; Reynolds, Matthew P; Jagadish, Krishna S V; Zhu, Chunwu; Howden, Mark; Wilson, Lloyd T

2012-10-22

Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO(2)) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO(2) to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO(2) and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO(2) responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change.

Internal Stress and Microstructure of Zinc Oxide Films Sputter-Deposited with Carbon Dioxide Gas

NASA Astrophysics Data System (ADS)

Toru Ashida,; Kazuhiro Kato,; Hideo Omoto,; Atsushi Takamatsu,

2010-06-01

The internal stress and microstructure of ZnO films were investigated as a function of carbon dioxide (CO2) gas flow ratio [CO2/(O2+CO2)] during sputter deposition. The internal stress of the ZnO films decreased with increasing CO2 gas flow ratio. The carbon concentration in the films deposited using CO2 gas increased by up to 4.0 at. %. Furthermore, the ZnO films deposited without CO2 gas exhibited a preferred orientation of (002); however, the C-doped ZnO films exhibited random orientations. These findings suggest that the C atoms incorporated in the ZnO crystal lattice induce this random orientation, thereby relaxing the internal stress of C-doped ZnO films.

Effects of alprazolam and clonidine on carbon dioxide-induced increases in anxiety rating in healthy human subjects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woods, S.W.; Krystal, J.H.; Heninger, G.R.

1989-01-01

In order to investigate possible neurobiologic mechanisms underlying carbon dioxide-induced anxiety, the effects of oral alprazolam 0.75 mg and intravenous clonidine 2 mcg/kg on CO/sub 2/-induced increases in ratings of subjective anxiety, pulse rate, and ventilation were measured in healthy human subjects. Pretreatment with alprazolam but not with clonidine significantly reduced the CO/sub 2/-induced increases in ratings of anxiety. Neither drug altered CO/sub 2/-induced increases in pulse rate or ventilatory responses. Clonidine did produce potent sedative and hypotensive effects. The behavioral data suggest that the mechanisms through which CO/sub 2/ induces anxiety-like effects involve neural systems regulated by benzodiazepine receptorsmore » and, secondly, that they appear not to require normal functioning of noradrenergic systems. Carbon dioxide may provide a useful model system for identification of new drugs with anxiolytic properties.« less

A Novel Airborne Carbon Isotope Analyzer for Methane and Carbon Dioxide Source Fingerprinting

NASA Astrophysics Data System (ADS)

Berman, E. S.; Huang, Y. W.; Owano, T. G.; Leifer, I.

2014-12-01

Recent field studies on major sources of the important greenhouse gas methane (CH4) indicate significant underestimation of methane release from fossil fuel industrial (FFI) and animal husbandry sources, among others. In addition, uncertainties still exist with respect to carbon dioxide (CO2) measurements, especially source fingerprinting. CO2 isotopic analysis provides a valuable in situ measurement approach to fingerprint CH4 and CO2as associated with combustion sources, leakage from geologic reservoirs, or biogenic sources. As a result, these measurements can characterize strong combustion source plumes, such as power plant emissions, and discriminate these emissions from other sources. As part of the COMEX (CO2 and MEthane eXperiment) campaign, a novel CO2 isotopic analyzer was installed and collected data aboard the CIRPAS Twin Otter aircraft. Developing methods to derive CH4 and CO2 budgets from remote sensing data is the goal of the summer 2014 COMEX campaign, which combines hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages the synergy between high spatial resolution HSI and moderate spatial resolution NIS. The carbon dioxide isotope analyzer developed by Los Gatos Research (LGR) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology and incorporates proprietary internal thermal control for high sensitivity and optimal instrument stability. This analyzer measures CO2 concentration as well as δ13C, δ18O, and δ17O from CO2 at natural abundance (100-3000 ppm). The laboratory accuracy is ±1.2 ppm (1σ) in CO2 from 370-1000 ppm, with a long-term (1000 s) precision of ±0.012 ppm. The long-term precision for both δ13C and δ18O is 0.04 ‰, and for δ17O is 0.06 ‰. The analyzer was field-tested as part of the COWGAS campaign, a pre-cursor campaign to COMEX in March 2014, where it successfully discriminated plumes related to combustion processes associated with dairy activities (tractor exhaust) from plumes and sources in air enriched in methane and ammonia from bovine activities including waste maintenance. Methodology, laboratory data, field data from COWGAS, and field data from the COMEX campaign acquired by LGR's carbon isotope analyzer as well as other COMEX analyzers are presented.

Physico-chemical effects of supercritical carbon dioxide post polymerization treatment on HCl-doped polyaniline prepared via oxidative chemical polymerization

NASA Astrophysics Data System (ADS)

Fernando, J. G.; Vequizo, R. M.; Odarve, M. K. G.; Sambo, B. R. B.; Alguno, A. C.; Malaluan, R. M.; Candidato, R. T., Jr.; Gambe, J. E.; Jabian, M.; Paylaga, G. J.; Bagsican, F. R. G.; Miyata, H.

2015-06-01

Polyanilinefilms doped with varying HClconcentrations (0.2 M, 0.6 M and 1.0 M) were synthesized on glass substrates via oxidative polymerization of aniline. The films were treated with supercritical carbon dioxide (SC-CO2) at 30 MPa and 40°C for 30 minutes. Their structural, optical and morphological properties were studied and compared to conventionally prepared polyanilinefilms using FTIR analysis, UVVisspectroscopy and scanning electron microscopy. It was observed that supercritical carbon dioxide (SC-CO2) could interact with PANI films that consequently altered the bandgapsand changed the film thickness. SC-CO2 treatment also increased the oxidation level of polyanilinefilms and modified the morphology of polyanilinefilm doped with 1M HCl.

Corona Preionization Technique for Carbon Dioxide TEA Lasers.

DTIC Science & Technology

1982-11-30

34’" " " " "- -. .. " "I~ 82R8O701-02 CORONA PREIONIZATION TECHNIQUE FOR CARBON DIOXIDE TEA LASERS W after R. Kamnki SUnited Technologiles Research Center C...TITLE (and Subtitle) S. TYPE OF REPORT a PERIOD COVERED CORONA PREIONIZATION TECHNIQUE FOR CARBON Final Report DIOXIDE TEA LASERS May 5, 1981...Preionization Laser UV Preionization Pulsed CO2 Laser Corona Preionization CO2 TEA Laser 10. ABSTRACT (Continue on reverse side If neceeeiny md Identify

Alkali injection system with controlled CO.sub.2 /O.sub.2 ratios for combustion of coal

DOEpatents

Berry, Gregory F.

1988-01-01

A high temperature combustion process for an organic fuel containing sulfur n which the nitrogen of air is replaced by carbon dioxide for combination with oxygen with the ratio of CO.sub.2 /O.sub.2 being controlled to generate combustion temperatures above 2000 K. for a gas-gas reaction with SO.sub.2 and an alkali metal compound to produce a sulfate and in which a portion of the carbon-dioxide rich gas is recycled for mixing with oxygen and/or for injection as a cooling gas upstream from heating exchangers to limit fouling of the exchangers, with the remaining carbon-dioxide rich gas being available as a source of CO.sub.2 for oil recovery and other purposes.

Recovery of Minerals in Martian Soils Via Supercritical Fluid Extraction

NASA Astrophysics Data System (ADS)

Debelak, Kenneth A.; Roth, John A.

2001-03-01

We are investigating the use of supercritical fluids to extract mineral and/or carbonaceous material from Martian surface soils and its igneous crust. Two candidate supercritical fluids are carbon dioxide and water. The Martian atmosphere is composed mostly of carbon dioxide (approx. 95.3%) and could therefore provide an in-situ source of carbon dioxide. Water, although present in the Martian atmosphere at only approx. 0.03%, is also a candidate supercritical solvent. Previous work done with supercritical fluids has focused primarily on their solvating properties with organic compounds. Interestingly, the first work reported by Hannay and Hogarth at a meeting of the Royal Society of London in 1879 observed that increasing or decreasing the pressure caused several inorganic salts e.g., cobalt chloride, potassium iodide, and potassium bromide, to dissolve or precipitate in supercritical ethanol. In high-pressure boilers, silica, present in most boiler feed waters, is dissolved in supercritical steam and transported as dissolved silica to the turbine blades. As the pressure is reduced the silica precipitates onto the turbine blades eventually requiring the shutdown of the generator. In supercritical water oxidation processes for waste treatment, dissolved salts present a similar problem. The solubility of silicon dioxide (SiO2) in supercritical water is shown. The solubility curve has a shape characteristic of supercritical systems. At a high pressure (greater than 1750 atmospheres) increasing the temperature results in an increase in solubility of silica, while at low pressures, less than 400 atm., the solubility decreases as temperature increases. There are only a few studies in the literature where supercritical fluids are used in extractive metallurgy. Bolt modified the Mond process in which supercritical carbon monoxide was used to produce nickel carbonyl (Ni(CO)4). Tolley and Tester studied the solubility of titanium tetrachloride (TiCl4) in supercritical CO2. They reported complete miscibility of TiCl4 with supercritical CO2 (infinite solubility). At 1500 psig, TiCl4 and CO2 form a single liquid phase below 50 C. Tolley et al. also reported on the solubility and thermodynamics of tin tetrachloride in supercritical CO2. Some of their data for TiC14 are shown. Three criteria have been suggested to predict which materials are suitable for supercritical extraction: 1) Hydrocarbons or lipophilic compounds of low molecular weight and polarity are easily extracted with supercritical CO2. 2) Compounds with polar groups are not easily extracted with supercritical CO2. 3) Separation of mixtures is facilitated if components differing mass, vapor pressure, or polarity.

Long-term effects of elevated carbon dioxide concentration on sour orange wood specific gravity, modulus of elasticity, and microfibril angle

Treesearch

David Kretschmann; James Evans; Mike Wiemann; Bruce A. Kimball; Sherwood B. Idso

2007-01-01

The carbon dioxide (CO2) concentration of Earth’s atmosphere continues to rise. Plants in general are responsive to changing CO2 concentrations, which suggests changes in agricultural productivity in the United States and around the world. The ability of plants to absorb CO2 during photosynthesis and then store carbon in their structure or sequester it in the soil has...

The temporal dynamics of carbon dioxide under snow in a high elevation Rocky Mountain subalpine forest and meadow

Treesearch

R. C. Musselman; W. J. Massman; J. M. Frank; J. L. Korfmacher

2005-01-01

Carbon dioxide (CO2) concentration under snow was examined through two winter seasons at a 3100 m elevation subalpine site in the Snowy Range of Wyoming. CO2 was monitored every half hour at the soil/snow interface, and at about 25 cm soil depth the second year, in a meadow and in an adjacent forest. CO2 under snow in the meadow was significantly higher than that in...

Selective Formation of Trimethylene Carbonate (TMC): Atmospheric Pressure Carbon Dioxide Utilization

PubMed Central

Buckley, Benjamin R; Patel, Anish P; Wijayantha, K G Upul

2015-01-01

Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO2 and its possible application as a C1 building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer. PMID:26213485

Selective Formation of Trimethylene Carbonate (TMC): Atmospheric Pressure Carbon Dioxide Utilization.

PubMed

Buckley, Benjamin R; Patel, Anish P; Wijayantha, K G Upul

2015-01-01

Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO 2 and its possible application as a C 1 building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer.

Reduction of Bromate by Cobalt-Impregnated Biochar Fabricated via Pyrolysis of Lignin Using CO2 as a Reaction Medium.

PubMed

Cho, Dong-Wan; Kwon, Gihoon; Ok, Yong Sik; Kwon, Eilhann E; Song, Hocheol

2017-04-19

In this study, pyrolysis of lignin impregnated with cobalt (Co) was conducted to fabricate a Co-biochar (i.e., Co/lignin biochar) for use as a catalyst for bromate (BrO 3 - ) reduction. Carbon dioxide (CO 2 ) was employed as a reaction medium in the pyrolysis to induce desired effects associated with CO 2 ; (1) the enhanced thermal cracking of volatile organic compounds (VOCs) evolved from the thermal degradation of biomass, and (2) the direct reaction between CO 2 and VOCs, which resulted in the enhanced generation of syngas (i.e., H 2 and CO). This study placed main emphases on three parts: (1) the role of impregnated Co in pyrolysis of lignin in the presence of CO 2 , (2) the characterization of Co/lignin biochar, and (3) evaluation of catalytic capability of Co-lignin biochar in BrO 3 - reduction. The findings from the pyrolysis experiments strongly evidenced that the desired CO 2 effects were strengthened due to catalytic effect of impregnated Co in lignin. For example, the enhanced generation of syngas from pyrolysis of Coimpregnated lignin in CO 2 was more significant than the case without Co impregnation. Moreover, pyrolysis of Coimpregnated lignin in CO 2 led to production of biochar of which surface area (599 m 2 g -1 ) is nearly 100 times greater than the biochar produced in N 2 (6.6 m 2 g -1 ). Co/lignin biochar produced in CO 2 also showed a great performance in catalyzing BrO 3 - reduction as compared to the biochar produced in N 2 .

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

Treesearch

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

2004-01-01

Global emissions of atmospheric CO2 and tropospheric O3 are rising and expected to impact large areas of the Earth's forests. While CO2 stimulates net primary production, O3 reduces photosynthesis, altering plant C allocation and reducing ecosystem C storage. The effects...

Chemical composition and digestibility of Trifolium exposed to elevated ozone and carbon dioxide in a free-air (FACE) fumigation system

Treesearch

R.B. Muntifering; A.H. Chappelka; J.C. Lin; D.F. Karnosky; G.L. Somers

2006-01-01

Tropospheric ozone (O3) and carbon dioxide (CO2) are significant drivers of plant growth and chemical composition. We hypothesized that exposure to elevated concentrations of O3 and CO2, singly and in combination, would modify the chemical composition of Trifolium...

Recent and projected increases in atmospheric carbon dioxide are associated with enhanced concentration of the anti-malarial compound, artemesinin

USDA-ARS?s Scientific Manuscript database

Although direct impacts on plant biology, in response to projected increases in atmospheric carbon dioxide [CO2], have been well established experimentally, data quantifying recent (20th century) impacts of [CO2] on plant chemical composition are undocumented. Yet, such impacts could include change...

SIMULATION OF CARBON DIOXIDE EMISSIONS FROM DAIRY FARMS TO ASSESS GREENHOUSE GAS REDUCTION STRATEGIES

USDA-ARS?s Scientific Manuscript database

Farming practices can have a large impact on the soil carbon cycle and the resulting net emission of greenhouse gases including carbon dioxide (CO**2), methane and nitrous oxide. Primary sources of CO**2 emission on dairy farms are soil, plant, and animal respiration with smaller contributions from ...

UNDERSTANDING AND MANAGING RISKS POSED BY BRINES CONTAINING DISSOLVED CARBON DIOXIDE

EPA Science Inventory

Geologic disposal of supercritical carbon dioxide in saline aquifers and depleted oil and gas fields will cause large volumes of brine to become saturated with dissolved CO₂ at concentrations of 50 g/l or more.  As CO₂ dissolves in brine, the brine de...

Evaluation of statistical protocols for quality control of ecosystem carbon dioxide fluxes

Treesearch

Jorge F. Perez-Quezada; Nicanor Z. Saliendra; William E. Emmerich; Emilio A. Laca

2007-01-01

The process of quality control of micrometeorological and carbon dioxide (CO2) flux data can be subjective and may lack repeatability, which would undermine the results of many studies. Multivariate statistical methods and time series analysis were used together and independently to detect and replace outliers in CO2 flux...

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide

PubMed Central

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, ChiHye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I.; Lee, Hoonkyung

2016-01-01

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10−3 bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc– or V–porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials. PMID:26902156

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide.

PubMed

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, ChiHye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I; Lee, Hoonkyung

2016-02-23

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10(-3) bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc- or V-porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials.

High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide

NASA Astrophysics Data System (ADS)

Bae, Hyeonhu; Park, Minwoo; Jang, Byungryul; Kang, Yura; Park, Jinwoo; Lee, Hosik; Chung, Haegeun; Chung, Chihye; Hong, Suklyun; Kwon, Yongkyung; Yakobson, Boris I.; Lee, Hoonkyung

2016-02-01

Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures (~10-3 bar) at 300 K and release it at ~450 K. CO2 binding to elements involves hybridization of the metal d orbitals with the CO2 π orbitals and CO2-transition metal complexes were observed in experiments. This result allows us to perform high-throughput screening to discover novel promising CO2 capture materials with empty d orbitals (e.g., Sc- or V-porphyrin-like graphene) and predict their capture performance under various conditions. Moreover, these findings provide physical insights into selective CO2 capture and open a new path to explore CO2 capture materials.

Response of Heterogeneous and Fractured Carbonate Samples to CO2-Brine Exposure

NASA Astrophysics Data System (ADS)

Smith, M. M.; Mason, H. E.; Hao, Y.; Carroll, S.

2014-12-01

Carbonate rock units are often considered as candidate sites for storage of carbon dioxide (CO2), whether as stand-alone reservoirs or coupled with enhanced oil recovery efforts. In order to accept injected carbon dioxide, carbonate reservoirs must either possess sufficient preexisting connected void space, or react with CO2-acidified fluids to produce more pore space and improve permeability. However, upward migration of CO2 through barrier zones or seal layers must be minimized for effective safe storage. Therefore, prediction of the changes to porosity and permeability in these systems over time is a key component of reservoir management. Towards this goal, we present the results of several experiments on carbonate core samples from the Wellington, Kansas 1-32 well, conducted under reservoir temperature, pressure, and CO2 conditions. These samples were imaged by X-ray computed tomography (XRCT) and analyzed with nuclear magnetic resonance (NMR) spectroscopy both prior to and after reaction with CO2-enriched brines. The carbonate samples each displayed distinct responses to CO2 exposure in terms of permeability change with time and relative abundance of calcite versus dolomite dissolution. The measured permeability of each sample was also much lower than that estimated by downhole NMR logging, with samples with larger fractured regions possessing higher permeability values. We present also our modeling approach and preliminary simulation results for a specific sample from the targeted injection zone. The heterogeneous composition as well as the presence of large fractured zones within the rock necessitated the use of a nested three-region approach to represent the range of void space observed via tomography. Currently, the physical response to CO2-brine flow (i.e., pressure declines with time) is reproduced well but the extent of chemical reaction is overestimated by the model.

Fetal blood gas values during fetoscopic myelomeningocele repair performed under carbon dioxide insufflation.

PubMed

Baschat, Ahmet A; Ahn, Edward S; Murphy, Jamie; Miller, Jena L

2018-05-10

Fetoscopic myelomeningocele (MMC) repair is performed with intrauterine carbon dioxide (CO 2 ) insufflation. While lamb experiments have shown significant fetal acidemia following CO 2 insufflation corresponding information for human pregnancies is not available. We performed umbilical venous cord blood sampling in three patients during fetoscopic MMC repair at 25+1, 25+3 and 24+1 weeks gestation. Fetal venous pH at the beginning of CO 2 insufflation were 7.36, 7.46 and 7.37; repeat values were 7.28, 7.35, 7.36 after 181, 159 and 149 minutes respectively. The partial pressure of oxygen and carbon dioxide was maintained in the normal range at these times and pH decrease was less in patient 3 receiving humidified CO2 insufflation. Our observations suggest that in contrast to sheep experiments, CO2 insufflation during fetoscopic myelomeningocele repair does not cause fetal acidemia. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Performance characteristics and modeling of carbon dioxide absorption by amines in a packed column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, S.H.; Shyu, C.T.

1999-01-01

Carbon dioxide (CO[sub 2]) is widely recognized as a major greenhouse gas contributing to global warming. To mitigate the global warming problem, removal of CO[sub 2] from the industrial flue gases is necessary. Absorption of carbon dioxide by amines in a packed column was experimentally investigated. The amines employed in the present study were the primary mono-ethanolamine (MEA) and tertiary N-methyldiethanolamine (MDEA), two very popular amines widely used in the industries for gas purification. The CO[sub 2] absorption characteristics by these two amines were experimentally examined under various operating conditions. A theoretical model was developed for describing the CO[sub 2]more » absorption behavior. Test data have revealed that the model predictions and the observed CO[sub 2] absorption breakthrough curves agree very well, validating the proposed model. Preliminary regeneration tests of exhausted amine solution were also conducted. The results indicated that the tertiary amine is easier to regenerate with less loss of absorption capacity than the primary one.« less

Three approaches for estimating recovery factors in carbon dioxide enhanced oil recovery

USGS Publications Warehouse

Verma, Mahendra K.

2017-07-17

PrefaceThe Energy Independence and Security Act of 2007 authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2) and requested the USGS to estimate the “potential volumes of oil and gas recoverable by injection and sequestration of industrial carbon dioxide in potential sequestration formations” (42 U.S.C. 17271(b)(4)). Geologic CO2 sequestration associated with enhanced oil recovery (EOR) using CO2 in existing hydrocarbon reservoirs has the potential to increase the U.S. hydrocarbon recoverable resource. The objective of this report is to provide detailed information on three approaches that can be used to calculate the incremental recovery factors for CO2-EOR. Therefore, the contents of this report could form an integral part of an assessment methodology that can be used to assess the sedimentary basins of the United States for the hydrocarbon recovery potential using CO2-EOR methods in conventional oil reservoirs.

Electrochemical energy storage device based on carbon dioxide as electroactive species

DOEpatents

Nemeth, Karoly; van Veenendaal, Michel Antonius; Srajer, George

2013-03-05

An electrochemical energy storage device comprising a primary positive electrode, a negative electrode, and one or more ionic conductors. The ionic conductors ionically connect the primary positive electrode with the negative electrode. The primary positive electrode comprises carbon dioxide (CO.sub.2) and a means for electrochemically reducing the CO.sub.2. This means for electrochemically reducing the CO.sub.2 comprises a conductive primary current collector, contacting the CO.sub.2, whereby the CO.sub.2 is reduced upon the primary current collector during discharge. The primary current collector comprises a material to which CO.sub.2 and the ionic conductors are essentially non-corrosive. The electrochemical energy storage device uses CO.sub.2 as an electroactive species in that the CO.sub.2 is electrochemically reduced during discharge to enable the release of electrical energy from the device.

Detection of CO2•- in the Electrochemical Reduction of Carbon Dioxide in N,N-Dimethylformamide by Scanning Electrochemical Microscopy.

PubMed

Kai, Tianhan; Zhou, Min; Duan, Zhiyao; Henkelman, Graeme A; Bard, Allen J

2017-12-27

The electrocatalytic reduction of CO 2 has been studied extensively and produces a number of products. The initial reaction in the CO 2 reduction is often taken to be the 1e formation of the radical anion, CO 2 •- . However, the electrochemical detection and characterization of CO 2 •- is challenging because of the short lifetime of CO 2 •- , which can dimerize and react with proton donors and even mild oxidants. Here, we report the generation and quantitative determination of CO 2 •- in N,N-dimethylformamide (DMF) with the tip generation/substrate collection (TG/SC) mode of scanning electrochemical microscopy (SECM). CO 2 was reduced at a hemisphere-shaped Hg/Pt ultramicroelectrode (UME) or a Hg/Au film UME, which were utilized as the SECM tips. The CO 2 •- produced can either dimerize to form oxalate within the nanogap between SECM tip and substrate or collected at SECM substrate (e.g., an Au UME). The collection efficiency (CE) for CO 2 •- depends on the distance (d) between the tip and substrate. The dimerization rate (6.0 × 10 8 M -1 s -1 ) and half-life (10 ns) of CO 2 •- can be evaluated by fitting the collection efficiency vs distance curve. The dimerized species of CO 2 •- , oxalate, can also be determined quantitatively. Furthermore, the formal potential (E 0 ') and heterogeneous rate constant (k 0 ) for CO 2 reduction were determined with different quaternary ammonium electrolytes. The significant difference in k 0 is due to a tunneling effect caused by the adsorption of the electrolytes on the electrode surface at negative potentials.

Ultrahigh porosity in metal-organic frameworks.

PubMed

Furukawa, Hiroyasu; Ko, Nakeun; Go, Yong Bok; Aratani, Naoki; Choi, Sang Beom; Choi, Eunwoo; Yazaydin, A Ozgür; Snurr, Randall Q; O'Keeffe, Michael; Kim, Jaheon; Yaghi, Omar M

2010-07-23

Crystalline solids with extended non-interpenetrating three-dimensional crystal structures were synthesized that support well-defined pores with internal diameters of up to 48 angstroms. The Zn4O(CO2)6 unit was joined with either one or two kinds of organic link, 4,4',4''-[benzene-1,3,5-triyl-tris(ethyne-2,1-diyl)]tribenzoate (BTE), 4,4',44''-[benzene-1,3,5-triyl-tris(benzene-4,1-diyl)]tribenzoate (BBC), 4,4',44''-benzene-1,3,5-triyl-tribenzoate (BTB)/2,6-naphthalenedicarboxylate (NDC), and BTE/biphenyl-4,4'-dicarboxylate (BPDC), to give four metal-organic frameworks (MOFs), MOF-180, -200, -205, and -210, respectively. Members of this series of MOFs show exceptional porosities and gas (hydrogen, methane, and carbon dioxide) uptake capacities. For example, MOF-210 has Brunauer-Emmett-Teller and Langmuir surface areas of 6240 and 10,400 square meters per gram, respectively, and a total carbon dioxide storage capacity of 2870 milligrams per gram. The volume-specific internal surface area of MOF-210 (2060 square meters per cubic centimeter) is equivalent to the outer surface of nanoparticles (3-nanometer cubes) and near the ultimate adsorption limit for solid materials.

Testing of some assumptions about biodegradability in soil as measured by carbon dioxide evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

El-Din Sharabi, N.; Bartha, R.

1993-04-01

The Toxic Substance Control Act calls for a premanufacturing review of novel chemical substances including their biodegradability. Carbon dioxide evolution, using non-labeled carbon or [sup 14]C, is a common method of testing. This study examines assumptions of carbon dioxide evolution testing. Test substances used included: glucose, adipic acid, benzoic acid, and n-hexadecane. Chemical composition other than carbon content appears to influence minimally the percentages conversion to CO[sub 2]. However, that although CO[sub 2] evolution seemed proportional to the carbon content and concentration of the test substance, at least one-half of the evolved net CO[sub 2] did not come directly frommore » the test substance. Conversion to CO[sub 2] in the soil appeared to depend on carbon content only. In experiments of 1 month or longer, the net CO[sub 2] evolution in response to substrate may be above 100% of the added substrate carbon. Whether this applies to all substrate additions remains to be studied. The authors conclude that net CO[sub 2] and [sup 14]CO[sub 2] evolution measurements are useful as a first-tier tests for assessing biodegradability in soil. 11 refs., 6 figs.« less

Performance evaluation of trimethylamine-carbon dioxide thermolytic draw solution for engineered osmosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boo, C; Khalil, YF; Elimelech, M

We evaluated the performance of trimethylamine-carbon dioxide (TMA-CO2) as a potential thermolytic draw solution for engineered osmosis. Water flux and reverse solute flux with TMA-CO2 draw solution were measured in forward osmosis (FO) and pressure retarded osmosis (PRO) modes using thin-film composite (TFC) and cellulose triacetate (CTA) FO membranes. Water flux with the TMA-CO2 draw solution was comparable to that obtained with the more common ammonia-carbon dioxide (NH3-CO2) thermolytic draw solution at similar (1 M) concentration. Using a TFC-FO membrane, the water fluxes produced by 1 M TMA-CO2 and NH3-CO2 draw solutions with a DI water feed were, respectively, 33.4more » and 35.6 L m(-2) h(-1) in PRO mode and 14.5 and 152 L m(-2) h(-1) in FO mode. Reverse draw permeation of TMA-CO2 was relatively low compared to NH3-CO2, ranging from 0.1 to 0.2 mol m(-2) h(-1) in all experiments, due to the larger molecular size of TMA. Thermal separation and recovery efficiency for TMA-CO2 was compared to NH3-CO2 by modeling low-temperature vacuum distillation utilizing low-grade heat sources. We also discuss possible challenges in the use TMA-CO2, including potential adverse impact on human health and environments. (C) 2014 Elsevier B.V. All rights reserved.« less

CO2 blood test

MedlinePlus

Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum; Acidosis - CO2; Alkalosis - CO2 ... Many medicines can interfere with blood test results. Your health ... need to stop taking any medicines before you have this test. DO ...

Does agricultural ecosystem cause environmental pollution in Pakistan? Promise and menace.

PubMed

Ullah, Arif; Khan, Dilawar; Khan, Imran; Zheng, Shaofeng

2018-05-01

The increasing trend of atmospheric carbon dioxide (CO 2 ) is the main cause of harmful anthropogenic greenhouse gas emissions, which may result in environmental pollution, global warming, and climate change. These issues are expected to adversely affect the agricultural ecosystem and well-being of the society. In order to minimize food insecurity and prevent hunger, a timely adaptation is desirable to reduce potential losses and to seek alternatives for promoting a global knowledge system for agricultural sustainability. This paper examines the causal relationship between agricultural ecosystem and CO 2 emissions as an environmental pollution indicator in Pakistan from the period 1972 to 2014 by employing Johansen cointegration, autoregressive distributed lag (ARDL) model, and Granger causality approach. The Johansen cointegration results show that there is a significant long-run relationship between the agricultural ecosystem and the CO 2 emissions. The long-run relationship shows that a 1% increase in biomass burned crop residues, emissions of CO 2 equivalent of nitrous oxide (N 2 O) from synthetic fertilizers, stock of livestock, agricultural machinery, cereal production, and other crop productions will increase CO 2 emissions by 1.29, 0.05, 0.45, 0.05, 0.03, and 0.65%, respectively. Further, our finding detects that there is a bidirectional causality of CO 2 emissions with rice area paddy harvested, cereal production, and other crop productions. The impulse response function analysis displays that biomass-burned crop residues, stock of livestock, agriculture machinery, cereal production, and other crop productions are significantly contributing to CO 2 emissions in Pakistan.

Carbon Dioxide Fluctuations Are Associated with Changes in Cerebral Oxygenation and Electrical Activity in Infants Born Preterm.

PubMed

Dix, Laura Marie Louise; Weeke, Lauren Carleen; de Vries, Linda Simone; Groenendaal, Floris; Baerts, Willem; van Bel, Frank; Lemmers, Petra Maria Anna

2017-08-01

To evaluate the effects of acute arterial carbon dioxide partial pressure changes on cerebral oxygenation and electrical activity in infants born preterm. This retrospective observational study included ventilated infants born preterm with acute fluctuations of continuous end-tidal CO 2 (etCO 2 ) as a surrogate marker for arterial carbon dioxide partial pressure, during the first 72 hours of life. Regional cerebral oxygen saturation and fractional tissue oxygen extraction were monitored with near-infrared spectroscopy. Brain activity was monitored with 2-channel electroencephalography. Spontaneous activity transients (SATs) rate (SATs/minute) and interval between SATs (in seconds) were calculated. Ten-minute periods were selected for analysis: before, during, and after etCO 2 fluctuations of ≥5  mm Hg. Thirty-eight patients (mean ± SD gestational age of 29 ± 1.8 weeks) were included, with 60 episodes of etCO 2 increase and 70 episodes of etCO 2 decrease. During etCO 2 increases, brain oxygenation increased (regional cerebral oxygen saturation increased, fractional tissue oxygen extraction decreased; P < .01) and electrical activity decreased (SATs/minute decreased, interval between SATs increased; P < .01). All measures recovered when etCO 2 returned to baseline. During etCO 2 decreases, brain oxygenation decreased (regional cerebral oxygen saturation decreased, fractional tissue oxygen extraction decreased; P < .01) and brain activity increased (SATs/minute increased, P < .05), also with recovery after return of etCO 2 to baseline. An acute increase in etCO 2 is associated with increased cerebral oxygenation and decreased brain activity, whereas an acute decrease is associated with decreased cerebral oxygenation and slightly increased brain activity. Combining continuous CO 2 monitoring with near-infrared spectroscopy may enable the detection of otherwise undetected fluctuations in arterial carbon dioxide partial pressure that may be harmful to the neonatal brain. Copyright © 2017 Elsevier Inc. All rights reserved.