Journal articles: 'CO2 density'

1

Gudipudi, Ramana, Till Fluschnik, Anselmo García Cantú Ros, Carsten Walther, and Jürgen P. Kropp. "City density and CO2 efficiency." Energy Policy 91 (April 2016): 352–61. http://dx.doi.org/10.1016/j.enpol.2016.01.015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Bartz, Marie Luise Carolina, George Gardner Brown, Amarildo Pasini, Juliana de Oliveira Fernandes, Pierre Curmi, Julie Dorioz, and Ricardo Ralisch. "Earthworm communities in organic and conventional coffee cultivation." Pesquisa Agropecuária Brasileira 44, no. 8 (August 2009): 928–33. http://dx.doi.org/10.1590/s0100-204x2009000800019.

Full text

Abstract:

The objective of this work was to evaluate the effect of organic and conventional coffee crops on biomass, population density and diversity of earthworms, in Lerroville, district of Londrina County, Paraná state, Brazil. Earthworm communities were sampled in three areas with organic coffee cultivation (CO1, CO2 and CO3), two with conventional coffee (CC1 and CC2), and a native forest fragment (MT). The soil of the areas CO1, CC1, and MT was classified as Nitossolo Vermelho (Rhodic Kandiudox), while CO2, CO3, and CC2 were on Latossolo Vermelho (Rhodic Hapludox). Eight samples were taken in each area on two occasions, winter and summer, using the Tropical Soil Biology and Fertility (TSBF) method in the 0-20 cm soil layer. The earthworms were handsorted and preserved in 4% formaldehyde, and were later weighed, counted and identified. The highest earthworm biomass, both in winter and summer, occurred in the CO3 area. For population density, the higher numbers of individuals were found in CO1 and CO3. The highest number of species was identified in the organic cultivation. The adoption of organic practices in coffee cultivation favored the diversity, density and biomass of earthworm communities.

APA, Harvard, Vancouver, ISO, and other styles

3

Jin, Zhenyu, Yingqing Guo, and Chaozhi Qiu. "Electro-Conversion of Carbon Dioxide to Valuable Chemicals in a Membrane Electrode Assembly." Sustainability 14, no. 9 (May 6, 2022): 5579. http://dx.doi.org/10.3390/su14095579.

Full text

Abstract:

Electro-conversion of carbon dioxide (CO2) into valuable chemicals is an efficient method to deal with excessive CO2 in the atmosphere. However, undesirable CO2 reaction kinetics in the bulk solution strongly limit current density, and thus it is incompetent in market promotion. Flow cell technology provides an insight into uplifting current density. As an efficient flow cell configuration, membrane electrode assembly (MEA) has been proposed and proven as a viable technology for scalable CO2 electro-conversion, promoting current density to several hundred mA/cm2. In this review, we systematically reviewed recent perspectives and methods to put forward the utilization of state-of-the-art MEA to convert CO2 into valuable chemicals. Configuration design, catalysts nature, and flow media were discussed. At the end of this review, we also presented the current challenges and the potential directions for potent MEA design. We hope this review could offer some clear, timely, and valuable insights on the development of MEA for using wastewater-produced CO2.

APA, Harvard, Vancouver, ISO, and other styles

4

Cunico, Larissa P., and Charlotta Turner. "Density Measurements of CO2-Expanded Liquids." Journal of Chemical & Engineering Data 62, no. 10 (September 11, 2017): 3525–33. http://dx.doi.org/10.1021/acs.jced.7b00540.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Wang, Zhiyuan, Baojiang Sun, and Linlin Yan. "Improved Density Correlation for Supercritical CO2." Chemical Engineering & Technology 38, no. 1 (November 27, 2014): 75–84. http://dx.doi.org/10.1002/ceat.201400357.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Shi, Jin, You Jian Jia, Feng Shi, and Xiao Chun Wang. "Electrochemical Reduction of Carbon Dioxide in 1-Ethyl-3-Methylimidazolium BF₄/Methanol Electrolyte." Advanced Materials Research 781-784 (September 2013): 2573–76. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2573.

Full text

Abstract:

Carbon dioxide (CO2) can be electrochemically reduced to useful products under mild condition. In recent years, increased attempts have been devoted to use ionic liquid (IL) as the solvents, electrolytes and catalysts for CO2 reduction. However, owing to the high viscosity of ILs, CO2 diffusion in ILs is restrained, lead to low current density of CO2 reduction. To overcome this problem, in present work, we used methanol as the organic solvent to dilute 1-Ethyl-3-Methylimidazolium BF4 ([EmiBF4), an commonly used IL in electrochemistry, the obtained [BmiBF4/methanol solution have many unique properties, such as low viscosity, high ionic conductivity, high CO2 solubility and low cost. The current density of CO2 reduction reached 14.2 mA/cm2 at-1.95V (vs SCE) on Ag electrode. Electrochemical reduction of CO2 in [BmiBF4/methanol solution provides a hopeful technique for CO2 recycling utilization and renewable electrical energy storage.

APA, Harvard, Vancouver, ISO, and other styles

7

Bastami, Alireza, Peyman Pourafshary, and Ali Shafiei. "Densities for Ternary System of CaCl2–H2O–CO2 at Elevated P-T: An Experimental and Modeling Approach." Energies 11, no. 10 (October 20, 2018): 2840. http://dx.doi.org/10.3390/en11102840.

Full text

Abstract:

Very few thermodynamic models exist for estimation of density alteration due to solution of CO2 in a pure H2O and CaCl2–H2O system. All of these models require density of CaCl2 solution to estimate density of CaCl2–H2O–CO2 system. Similarly, models presented to calculate CaCl2 solution density need pure H2O density in advance. The main approach to model density of CaCl2–H2O–CO2 system is based on estimation of density alteration of CaCl2–H2O system due to the solution of CO2 mole fraction. Hence, to estimate CO2–CaCl2–H2O system density, density of CaCl2 solution is necessary, and to estimate density of CaCl2–H2O system, density of pure H2O is required in advance. Firstly in this paper, density of 0, 1.91, and 4.85 mol/kg CaCl2 solutions saturated with CO2 at 328.15 to 375.15 °K and 68.9 to 206.8 Bar were measured through laboratory experiments. Then, a new model is developed to estimate the density of CaCl2 solutions containing CO2 based on the experiments conducted in this study. The average and maximum absolute deviations of the new model from the experimental data are 0.0047 and 0.0177, respectively. Hence, the new model combined with other existing models to separately calculate density of the CaCl2 solution can be used to accurately predict density of the CaCl2–H2O–CO2 system in a wide range of P-T applicable for subsurface reservoirs.

APA, Harvard, Vancouver, ISO, and other styles

8

Aya, I., K. Yamane, and H. Nariai. "Solubility of CO2 and density of CO2 hydrate at 30 MPa." Energy 22, no. 2-3 (February 1997): 263–71. http://dx.doi.org/10.1016/s0360-5442(96)00093-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Zhang, Yi, Yong Shen, Yongchen Song, Yangchun Zhan, Masahiro Nishio, Weiwei Jian, Wanli Xing, and Cheng Hu. "Density Measurements of Supercritical CO2 + Dagang Brine for CO2 Geological Storage." Energy Procedia 37 (2013): 5620–27. http://dx.doi.org/10.1016/j.egypro.2013.06.484.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Mantovani, Mario, Paolo Chiesa, Gianluca Valenti, Manuele Gatti, and Stefano Consonni. "Supercritical pressure–density–temperature measurements on CO2–N2, CO2–O2 and CO2–Ar binary mixtures." Journal of Supercritical Fluids 61 (January 2012): 34–43. http://dx.doi.org/10.1016/j.supflu.2011.09.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Schwartz, Robert S., Sylvia Musto, Mary E. Fabry, and Ronald L. Nagel. "Two Distinct Pathways Mediate the Formation of Intermediate Density Cells and Hyperdense Cells From Normal Density Sickle Red Blood Cells." Blood 92, no. 12 (December 15, 1998): 4844–55. http://dx.doi.org/10.1182/blood.v92.12.4844.

Full text

Abstract:

Abstract In sickle cell anemia (SS), some red blood cells dehydrate, forming a hyperdense (HD) cell fraction (>1.114 g/mL; mean corpuscular hemoglobin concentration [MCHC], >46 g/dL) that contains many irreversibly sickled cells (ISCs), whereas other SS red blood cells dehydrate to an intermediate density (ID; 1.090 to 1.114 g/mL; MCHC, 36 to 46 g/dL). This study asks if the potassium-chloride cotransporter (K:Cl) and the calcium-dependent potassium channel [K(Ca2+)] are participants in the formation of one or both types of dense SS red blood cells. We induced sickling by exposing normal density (ND; 1.080 to 1.090 g/mL; MCHC, 32 to 36 g/dL) SS discocytes to repetitive oxygenation-deoxygenation (O-D) cycles in vitro. At physiologic Na+, K+, and Cl−, and 0.5 to 2 mmol/L Ca2+, the appearance of dense cells was time- and pH-dependent. O-D cycling at pH 7.4 in 5% CO2-equilibrated buffer generated only ID cells, whereas O-D cycling at pH 6.8 in 5% CO2-equilibrated buffer generated both ID and HD cells, the latter taking more than 8 hours to form. At 22 hours, 35% ± 17% of the parent ND cells were recovered in the ID fraction and 18% ± 11% in the HD fraction. Continuous deoxygenation (N2/5% CO2) at pH 6.8 generated both ID and HD cells, but many of these cells had multiple projections, clearly different from the morphology of endogenous dense cells and ISCs. Continuous oxygenation (air/5% CO2) at pH 6.8 resulted in less than 10% dense cell (ID + HD) formation. ATP depletion substantially increased HD cell formation and moderately decreased ID cell formation. HD cells formed after 22 hours of O-D cycling at pH 6.8 contained fewer F cells than did ID cells, suggesting that HD cell formation is particularly dependent on HbS polymerization. EGTA chelation of buffer Ca2+ inhibited HD but not ID cell formation, and increasing buffer Ca2+ from 0.5 to 2 mmol/L promoted HD but not ID cell formation in some SS patients. Substitution of nitrate for Cl− inhibited ID cell formation, as did inhibitors of the K:Cl cotransporter, okadaic acid, and [(dihydroindenyl) oxy]alkanoic acid (DIOA). Conversely, inhibitors of K(Ca2+), charybdotoxin and clotrimazole, inhibited HD cell formation. The combined use of K(Ca2+) and K:Cl inhibitors nearly eliminated dense cell (ID + HD cell) formation. In summary, dense cells formed by O-D cycling for 22 hours at pH 7.4 cycling are predominately the ID type, whereas dense cells formed by O-D cycling for 22 hours at pH 6.8 are both the ID and HD type, with the latter low in HbF, suggesting that HD cell formation has a greater dependency on HbS polymerization. A combination of K:Cl cotransport and the K(Ca2+) activities account for the majority of dense cells formed, and these pathways can be driven independently. We propose a model in which reversible sickling-induced K+ loss by K:Cl primarily generates ID cells and K+ loss by the K(Ca2+) channel primarily generates HD cells. These results imply that both pathways must be inhibited to completely prevent dense SS cell formation and have potential therapeutic implications.

APA, Harvard, Vancouver, ISO, and other styles

12

Schwartz, Robert S., Sylvia Musto, Mary E. Fabry, and Ronald L. Nagel. "Two Distinct Pathways Mediate the Formation of Intermediate Density Cells and Hyperdense Cells From Normal Density Sickle Red Blood Cells." Blood 92, no. 12 (December 15, 1998): 4844–55. http://dx.doi.org/10.1182/blood.v92.12.4844.424k29_4844_4855.

Full text

Abstract:

In sickle cell anemia (SS), some red blood cells dehydrate, forming a hyperdense (HD) cell fraction (>1.114 g/mL; mean corpuscular hemoglobin concentration [MCHC], >46 g/dL) that contains many irreversibly sickled cells (ISCs), whereas other SS red blood cells dehydrate to an intermediate density (ID; 1.090 to 1.114 g/mL; MCHC, 36 to 46 g/dL). This study asks if the potassium-chloride cotransporter (K:Cl) and the calcium-dependent potassium channel [K(Ca2+)] are participants in the formation of one or both types of dense SS red blood cells. We induced sickling by exposing normal density (ND; 1.080 to 1.090 g/mL; MCHC, 32 to 36 g/dL) SS discocytes to repetitive oxygenation-deoxygenation (O-D) cycles in vitro. At physiologic Na+, K+, and Cl−, and 0.5 to 2 mmol/L Ca2+, the appearance of dense cells was time- and pH-dependent. O-D cycling at pH 7.4 in 5% CO2-equilibrated buffer generated only ID cells, whereas O-D cycling at pH 6.8 in 5% CO2-equilibrated buffer generated both ID and HD cells, the latter taking more than 8 hours to form. At 22 hours, 35% ± 17% of the parent ND cells were recovered in the ID fraction and 18% ± 11% in the HD fraction. Continuous deoxygenation (N2/5% CO2) at pH 6.8 generated both ID and HD cells, but many of these cells had multiple projections, clearly different from the morphology of endogenous dense cells and ISCs. Continuous oxygenation (air/5% CO2) at pH 6.8 resulted in less than 10% dense cell (ID + HD) formation. ATP depletion substantially increased HD cell formation and moderately decreased ID cell formation. HD cells formed after 22 hours of O-D cycling at pH 6.8 contained fewer F cells than did ID cells, suggesting that HD cell formation is particularly dependent on HbS polymerization. EGTA chelation of buffer Ca2+ inhibited HD but not ID cell formation, and increasing buffer Ca2+ from 0.5 to 2 mmol/L promoted HD but not ID cell formation in some SS patients. Substitution of nitrate for Cl− inhibited ID cell formation, as did inhibitors of the K:Cl cotransporter, okadaic acid, and [(dihydroindenyl) oxy]alkanoic acid (DIOA). Conversely, inhibitors of K(Ca2+), charybdotoxin and clotrimazole, inhibited HD cell formation. The combined use of K(Ca2+) and K:Cl inhibitors nearly eliminated dense cell (ID + HD cell) formation. In summary, dense cells formed by O-D cycling for 22 hours at pH 7.4 cycling are predominately the ID type, whereas dense cells formed by O-D cycling for 22 hours at pH 6.8 are both the ID and HD type, with the latter low in HbF, suggesting that HD cell formation has a greater dependency on HbS polymerization. A combination of K:Cl cotransport and the K(Ca2+) activities account for the majority of dense cells formed, and these pathways can be driven independently. We propose a model in which reversible sickling-induced K+ loss by K:Cl primarily generates ID cells and K+ loss by the K(Ca2+) channel primarily generates HD cells. These results imply that both pathways must be inhibited to completely prevent dense SS cell formation and have potential therapeutic implications.

APA, Harvard, Vancouver, ISO, and other styles

13

Yorio, N. C., C. L. Mackowiak, R. M. Wheeler, and G. W. Stutte. "Stomatal Density and Index of Five Species of Crop Plants Grown at Elevated and Super-elevated CO2." HortScience 32, no. 3 (June 1997): 543B—543. http://dx.doi.org/10.21273/hortsci.32.3.543b.

Full text

Abstract:

The effects of elevated CO2 on stomatal density and index were investigated for five crop species currently being studied for NASA's Advanced Life Support program. Lettuce (cv. Waldmann's Green) and radish (cv. Giant White Globe) were grown at 400, 1000, 5000, or 10,000 μmol·mol–1 CO2, tomato (cvs. Red Robin and Reimann Philip 75/59) were grown at 400, 1200, 5000, or 10,000 μmol·mol–1 CO2, and wheat (cv. Yecora Rojo) and potato (cv. Denali) were grown at 400, 1000, or 10,000 μmol·mol–1 CO2 within controlled-environment growth chambers using nutrient film technique hydroponics. Leaf impressions were made by applying clear silicone-based RTV coating to the adaxial and abaxial leaf surfaces of three canopy leaves of each crop at each CO2 treatment. Impressions were examined using a light microscope, whereby the number of stomatal complexes and epidermal cells were counted to calculate stomatal density and stomatal index. Results indicate that stomatal density increased for lettuce and radish at 10,000 μmol·mol–1 CO2, whereas tomato density was highest at 1200 μmol·mol–1 CO2. Potato had the lowest density at 1000 μmol·mol–1 CO2, and there was no effect of CO2 on density for wheat. Stomatal index correlated with density for lettuce and tomato; however, stomatal index for radish, potato, and wheat was not influenced by CO2. This suggests that there may be a species-specific CO2 response to epidermal cell size that influences stomatal density and stomatal index.

APA, Harvard, Vancouver, ISO, and other styles

14

Lin, Jing, Shenglin Yan, Chunxiao Zhang, Qing Hu, and Zhenmin Cheng. "Electroreduction of CO2 toward High Current Density." Processes 10, no. 5 (April 22, 2022): 826. http://dx.doi.org/10.3390/pr10050826.

Full text

Abstract:

Carbon dioxide (CO2) electroreduction offers an attractive pathway for converting CO2 to valuable fuels and chemicals. Despite the existence of some excellent electrocatalysts with superior selectivity for specific products, these reactions are conducted at low current densities ranging from several mA cm−2 to tens of mA cm−2, which are far from commercially desirable values. To extend the applications of CO2 electroreduction technology to an industrial scale, long-term operations under high current densities (over 200 mA cm−2) are desirable. In this paper, we review recent major advances toward higher current density in CO2 reduction, including: (1) innovations in electrocatalysts (engineering the morphology, modulating the electronic structure, increasing the active sites, etc.); (2) the design of electrolyzers (membrane electrode assemblies, flow cells, microchannel reactors, high-pressure cells, etc.); and (3) the influence of electrolytes (concentration, pH, anion and cation effects). Finally, we discuss the current challenges and perspectives for future development toward high current densities.

APA, Harvard, Vancouver, ISO, and other styles

15

Marra, R. Kendall, Fred H. Poettmann, and Robert S. Thompson. "Density of Crude Oil Saturated With CO2." SPE Reservoir Engineering 3, no. 03 (August 1, 1988): 815–21. http://dx.doi.org/10.2118/16350-pa.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Guo, Hui, Li Hui, and Shufeng Shen. "Monoethanolamine+2-methoxyethanol mixtures for CO2 capture: Density, viscosity and CO2 solubility." Journal of Chemical Thermodynamics 132 (May 2019): 155–63. http://dx.doi.org/10.1016/j.jct.2018.12.028.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Teng, Ying, Pengfei Wang, Lanlan Jiang, Yu Liu, and Yang Wei. "New Spectrophotometric Method for Quantitative Characterization of Density-Driven Convective Instability." Polymers 13, no. 4 (February 23, 2021): 661. http://dx.doi.org/10.3390/polym13040661.

Full text

Abstract:

CO2 convective dissolution has been regarded as one of the fundamental mechanisms to accelerate the mass transfer of CO2 into brine. We present a new spectrophotometric method to characterize the convective instability and measure the dissolved CO2 mass, which enables the real-time quantitative visualization of CO2/brine transport mechanisms. Successive images were captured to identify the finger development regimes, and the convection morphologies were analyzed by the fingers length and affected area. CO2 solubility was experimentally studied, and the results are in agreement with the theoretical calculations. CO2 mass transfer flux was investigated as the Sherwood number changed. The increase in salinity and temperature has a negative effect on CO2 dissolution; here, numerical simulation and experimental phenomena are qualitatively consistent. In general, these findings confirm the feasibility of the method and improve the understanding of the physical process of CO2 convective dissolution, which can help assess the CO2 solubility trapping mass.

APA, Harvard, Vancouver, ISO, and other styles

18

Yassin, Mahmood Reza, Ali Habibi, Ashkan Zolfaghari, Sara Eghbali, and Hassan Dehghanpour. "An Experimental Study of Nonequilibrium Carbon Dioxide/Oil Interactions." SPE Journal 23, no. 05 (July 2, 2018): 1768–83. http://dx.doi.org/10.2118/187093-pa.

Full text

Abstract:

Summary In this study, we use a custom-designed visual cell to investigate nonequilibrium carbon dioxide (CO2)/oil interactions under high-pressure/high-temperature conditions. We visualize the CO2/oil interface and measure the visual-cell pressure over time. We perform five sets of visualization tests. The first three tests aim at investigating interactions of gaseous (g), liquid (l), and supercritical (sc) CO2 with a Montney (MTN) oil sample. In the fourth test, to visualize the interactions in the bulk oil phase, we replace the opaque MTN oil with a translucent Duvernay (DUV) light oil (LO). Finally, we conduct an N2(sc)/oil test to compare the results with those of CO2(sc)/oil test. We also compare the results of nonequilibrium CO2/oil interactions with those obtained from conventional pressure/volume/temperature (PVT) tests. Results of the first three tests show that oil immediately expands upon injection of CO2 into the visual cell. CO2(sc) leads to the maximum oil expansion followed by CO2(l) and CO2(g). Furthermore, the rate of oil expansion in the CO2(sc)/oil test is higher than that in CO2(l)/oil and CO2(g)/oil tests. We also observe extracting and condensing flows at the CO2(l)/oil and CO2(sc)/oil interfaces. Moreover, we observe density-driven fingers inside the LO phase because of the local increase in the density of LO. The results of PVT tests show that the density of the CO2/oil mixture is higher than that of the CO2-free oil, explaining the density-driven natural convection during CO2(sc) injection into the visual cell. We do not observe either extracting/condensing flows or density-driven mixing for the N2(sc)/oil test, explaining the low expansion of oil in this test. The results suggest that the combination of density-driven natural convection and extracting/condensing flows enhances CO2(sc) dissolution into the oil phase, leading to fast oil expansion after CO2(sc) injection into the visual cell.

APA, Harvard, Vancouver, ISO, and other styles

19

Wang, Zhi-Qiang, Hui-Hui Liu, Xin-Ping Wu, Peijun Hu, and Xue-Qing Gong. "Hydride Generation on the Cu-Doped CeO2(111) Surface and Its Role in CO2 Hydrogenation Reactions." Catalysts 12, no. 9 (August 29, 2022): 963. http://dx.doi.org/10.3390/catal12090963.

Full text

Abstract:

Ceria-based catalysts exhibit great activity in catalyzing selective hydrogenation of CO2 to methanol. However, the underlying mechanism of this reaction, especially the generation of active H species, remains unclear. In this work, we performed extensive density functional theory calculations corrected by on-site Coulomb interaction (DFT + U) to investigate the H2 dissociation and the reaction between the active H species and CO2 on the pristine and Cu-doped CeO2(111) (denoted as Cu/CeO2(111)) surfaces. Our calculations evidenced that the heterolytic H2 dissociation for hydride generation can more readily occur on the Cu/CeO2(111) surface than on the pristine CeO2(111) surface. We also found that the Cu dopant can facilitate the formation of surface oxygen vacancies, further promoting the generation of hydride species. Moreover, the adsorption of CO2 and the hydrogenation of CO2 to HCOO* can be greatly promoted on the Cu/CeO2(111) surface with hydride species, which can lead to the high activity and selectivity toward CO2 hydrogenation to methanol.

APA, Harvard, Vancouver, ISO, and other styles

20

Beaudry, Randolph M. "EFFECT OF ELEVATED CARBON DIOXIDE LEVELS ON BLUEBERRY FRUIT RESPIRATION AND RESPIRATORY QUOTIENT." HortScience 27, no. 6 (June 1992): 676f—676. http://dx.doi.org/10.21273/hortsci.27.6.676f.

Full text

Abstract:

Blueberry fruit were sealed in 0.00254 cm (1 mil) thick, 200 cm2 low density polyethylene pouches, which, in turn, were sealed in containers continually purged with gas mixtures containing 0, 20, 40 or 60 kPa CO2 and held at 15C. Sampling the gas composition of the enclosed package permitted accurate determination of O2 uptake, CO2 production and the respiratory quotient (RQ) despite the high background CO2 levels. O2 uptake was minimally affected by the CO2 treatments. CO2 production, however, increased at CO2 partial pressures over 20 kPa, resulting in an elevated RQ at 40 and 60 kPa CO2. Raising the CO2 partial pressure caused the fruit to become more sensitive to lowered O2, raising the O2 partial pressure associated with the RQ breakpoint.

APA, Harvard, Vancouver, ISO, and other styles

21

Luo, Yi Wei, Chun Ling Xin, Jiao Sun, Bao Rui Yan, and Ya Dong He. "Study on the Foaming Behavior of PS-CO₂ by Using Water or Ethanol as Co-Blowing Agent." Advanced Materials Research 748 (August 2013): 112–16. http://dx.doi.org/10.4028/www.scientific.net/amr.748.112.

Full text

Abstract:

Carbon dioxide (CO2) has been reported as an interesting substitute of banned ozone-depleting blowing agents, such as HCFC and HFC etc., for low-density polystyrene (PS) foam production, but it is difficult to industrialize due to its low solubility in PS matrix; therefore, high pressure is always needed in order to obtain the required gas concentrations for low density foam. Mixtures of blowing agents might be a practical way to make foam processing easy to control. In this paper, the foaming behaviors of PS-CO2 by using water or ethanol as co-blowing agent were investigated. The performances of foams obtained by PS-CO2, PS-CO2-water and PS-CO2-ethanol systems were tested respectively. It was found that cell size increased owing to the existence of co-blowing agent; in particular, the expansion ratio of PS foam obtained by CO2-ethanol was 1.3 times greater than that by CO2. At the same time, cell density as well as apparent density decreased with temperature increasing, while cell size showed the opposite. Cell size and apparent density, rather than cell density, decreased with pressure. These results were explained by the solution behavior of each of blowing agent.

APA, Harvard, Vancouver, ISO, and other styles

22

AKSAKAL, Hüsnü, and Vildan ÇİNĞİLİ. "Investigation of Radiation Properties of CO2 Reacted Portland." Süleyman Demirel Üniversitesi Fen Edebiyat Fakültesi Fen Dergisi 17, no. 2 (November 25, 2022): 391–404. http://dx.doi.org/10.29233/sdufeffd.1153537.

Full text

Abstract:

In this study we explored the radiation properties of CO2-reacted Portland which take place in kiln process of cement production. The use of CO2 can change Portland density via chemical process to obtain CaCO3. When the CO2 capture rate of Portland cement is zero, the density is 2.3 g/cm3, while the CO2 capture rate is 100%, the density is reached to 2.705 g/cm3. The radiation shielding properties were explored using FLUKA code. To define the radiation shielding properties of the CO2-reacted Portland, four types of beams (photons, electrons, protons and neutrons) were used. These beams have been used to explain the leptonic and hadronic interactions. The CO2-reacted Portland radiation length and density have been calculated and presented. The energy depositions of four beams with various beam energies were examined by considering density variation of the cement. It has been found that CO2-reacted Portland has more efficient radiation shielding than traditional Portland materials. The carbonization of Portland will be carried out during the kiln process, not by the CO2 diffusion process, which is a very slow process, but by the faster and more convenient spray method.

APA, Harvard, Vancouver, ISO, and other styles

23

Wang, Wanhua, Haixia Li, Ka-Young Park, Taehee Lee, and Fanglin (Frank) Chen. "Improving the Performance for Direct Electrolysis of CO₂ in Solid Oxide Electrolysis Cell with Sr_1.9Fe_1.5Mo_0.5 O₆ _- _δ Electrode Via Infiltration of Pr₆O₁₁ Nanoparticles." ECS Meeting Abstracts MA2022-02, no. 47 (October 9, 2022): 1778. http://dx.doi.org/10.1149/ma2022-02471778mtgabs.

Full text

Abstract:

High temperature direct CO2 electrolysis based on solid oxide electrolysis cell (CO2-SOEC) is a promising technology to convert carbon dioxide to carbon monoxide with a high current density and Faradaic efficiency. The exploration for suitable cathodes with desirable catalytic activity is a grand challenge for the development of CO2-SOEC. Sr2Fe1.5Mo0.5O6 - δ is often used as the cathode material for SOEC, but suffers from insufficient activity for CO2 reduction reaction (CO2RR). In this work, nanoscale Pr6O11 was infiltrated into the Sr1.9Fe1.5Mo0.5O6 - δ (SFM) electrode to promote the CO2RR performance in SOEC. The optimal loading of Pr6O11 is systematically investigated. At 800°C, the current density of the Pr6O11 infiltrated SFM cathode with a Pr6O11 loading of 13.4wt.% reaches 1.58 A/cm2 at 1.5V, which is 2.5 times higher than that of SFM cathode (0.63 A/cm2) at the same operating conditions. X-ray photoelectron spectroscopy characterization and temperature-programmed desorption of CO2 measurements indicate that the adsorption and desorption ability of CO2 of SFM cathode are improved by the infiltration of Pr6O11. Further, the polarization resistance of SFM cathode has significantly decreased with the infiltrated Pr6O11. These results demonstrate that the infiltration of Pr6O11 is a promising approach for increasing CO2RR activity. Acknowledgements Financial support from the U.S. Department of Energy (DE-EE0009427) and NASA EPSCoR (Grant # 80NSSC20M0233) is greatly appreciated.

APA, Harvard, Vancouver, ISO, and other styles

24

Hovenden, Mark J., and Lisa J. Schimanski. "Genotypic differences in growth and stomatal morphology of Southern Beech, Nothofagus cunninghamii, exposed to depleted CO2 concentrations." Functional Plant Biology 27, no. 4 (2000): 281. http://dx.doi.org/10.1071/pp99195.

Full text

Abstract:

Nothofagus cunninghamii (Hook.) Oerst. clones of four different genotypes from Mt Field National Park, Tasmania were grown at both current (~370 mol mol–1 ) and depleted (~170 mol mol –1 ) CO2. Growth was significantly less in the lower [CO2] treatment in all genotypes. The amount of growth reduction caused by low [CO2] depended strongly upon genotype and varied from less than 30% to greater than 75% reduction of whole plant biomass when compared to growth at current [CO2]. Specific leaf area was significantly greater in all plants grown in reduced [CO2], whereas individual leaf area was not significantly affected by [CO2]. The direction and magnitude of the response of stomatal index, stomatal density and epidermal cell density to [CO2] was strongly dependent upon genotype. [CO2] had a significant effect on the length of the stomatal pore, but the magnitude of the effect (~3%) was trivial compared to changes in stomatal density (up to 20%). There was a significant (P < 0.01) and positive relationship between the response of stomatal density and growth response of a genotype. Therefore, we propose that the response of stomatal density to [CO2] controls the relative growth response of N. cunninghamii and that this response is highly dependent upon genotype.

APA, Harvard, Vancouver, ISO, and other styles

25

Sembiring, S. S. B., R. Hermawan, and S. B. Rushayati. "The concentration of CO₂ on two canopy densities in Taman Kota 1 Bumi Serpong Damai, South Tangerang." IOP Conference Series: Earth and Environmental Science 918, no. 1 (November 1, 2021): 012008. http://dx.doi.org/10.1088/1755-1315/918/1/012008.

Full text

Abstract:

Abstract Global warming occurs because many greenhouse gases (GHG) retain heat from the earth, which causes the earth’s surface temperature to increase. The GHG contributing most to global warming is carbon dioxide (CO2) due to its highest atmosphere concentration and long life span. The increasing CO2 concentrations in urban areas are caused by transportation and industrial activities. City parks with high tree densities are the potential to reduce CO2 concentration. However, studies related to tree canopy density in reducing CO2 concentrations have not been widely carried out. This study aims to determine the CO2 concentration on two different canopy densities. This research was conducted in March - April 2021 in Taman Kota 1 BSD. Primary data collection was carried out by three replicates based on time as follows: 06.00 am, 01.00 pm, and 05.00 pm at low canopy density and high canopy density locations, respectively, by using the AZ 7725 Carbon dioxide meter tool. The low canopy density had a leaf area index (LAI) of 1.039, whereas the high canopy density had an LAI of 1.409. The highest CO2 concentration is 582.43 ppm in the high canopy density in the morning, while the lowest is 463.16 ppm occurred at the low canopy density in the afternoon. In the morning, CO2 from respiration is still concentrated under the dense canopy because there is less wind to disperse. In the afternoon, the wind speed is higher so that CO2 is more easily distributed.

APA, Harvard, Vancouver, ISO, and other styles

26

Malvin, G. "Microcirculatory effects of hypoxic and hypercapnic vasoconstriction in frog skin." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 264, no. 2 (February 1, 1993): R435—R439. http://dx.doi.org/10.1152/ajpregu.1993.264.2.r435.

Full text

Abstract:

The effects in frog (albino Xenopus laevis) skin of hypoxic and hypercapnic vasoconstriction on the following microcirculatory parameters were determined: capillary red blood cell flux, capillary red blood cell velocity, perfused capillary density, lineal red blood cell density, and the temporal heterogeneity of capillary red blood cell velocities. All of these parameters affect the gas exchange characteristics of respiratory organs. Measurements were made by fluorescent video microscopy of a 1.5-cm2 region of skin exposed to different gas mixtures (air, O2, N2, 5% CO2-95% air, 5% CO2-95% N2). N2 caused red blood cell flux and velocity to fall to 52 +/- 10% (P < 0.05) and 47 +/- 10% (P < 0.01), respectively, of those values during air exposure. Five percent CO2 caused capillary red blood cell flux and velocity to decrease by 51 +/- 11% (P < 0.05) and 43 +/- 11% (P < 0.01), respectively. Fluxes (P < 0.01) and velocities (P < 0.01) were also less with 5% CO2-95% N2 than with air. There were no significant differences in flux and velocity between N2, 5% CO2-95% air and 5% CO2-95% N2 (P > 0.1). There was no significant difference in flux or in velocity between O2 and air (P > 0.1). Gas composition had no significant effect on lineal red blood cell density (P > 0.35) or the density of perfused capillaries (P > 0.22). The heterogeneity of cell velocities was significantly greater with N2 than with the other gases (P < 0.01). There was no significant difference in red blood cell velocity heterogeneity between the other gases (P > 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

27

Kee, Wong Mee, Azmi Mohd Shariff, Mohammad Azmi Bustam, Lau Kok Keong, Turgkaraaj Karikalan, and Ghulam Murshid. "Density, Viscosity and CO₂ Solubility of Novel Solvent." Advanced Materials Research 917 (June 2014): 301–6. http://dx.doi.org/10.4028/www.scientific.net/amr.917.301.

Full text

Abstract:

Carbon dioxide (CO2) is the major cause of accelerating global warming. It is important to employ efficient method to capture CO2. Absorption is the most established technique to separate CO2 and amines are most commonly used as solvent. In this study, density and viscosity of an amine based novel solvent named Stonvent were investigated at temperature ranging from 298.15 K to 338.15 K. CO2 solubility in Stonvent was measured at varying pressures, temperatures and concentrations. The experiments were conducted at temperatures (303.15, 318.15 and 333.15) K, and at pressures (0.5, 1, 1.5 and 3) MPa over a wide range of concentration (10, 20, 30 and 100) mass %. Solubility of CO2 was determined from pressure drop due to absorption of CO2 into solvent within equilibrium cell. Absorption capacity of Stonvent increases significantly with increasing pressure. Solubility of CO2 in Stonvent is higher compared to Monoethanolamine (MEA), 1-amino-2-propanol (MIPA) and 2-amino-2-methyl-1,3-propanediol (AMPD) at elevated pressure, hence posing Stonvent as an attractive alternative for acid gas absorption in high pressure conditions. Substantial increase in CO2 loading was observed when concentration of Stonvent is increased and when temperature is decreased.

APA, Harvard, Vancouver, ISO, and other styles

28

Chen, Lei, Takumi Watanabe, Hirofumi Kanoh, Kenji Hata, and Tomonori Ohba. "Cooperative CO2 adsorption promotes high CO2 adsorption density over wide optimal nanopore range." Adsorption Science & Technology 36, no. 1-2 (June 9, 2017): 625–39. http://dx.doi.org/10.1177/0263617417713573.

Full text

Abstract:

Separation of CO2 based on adsorption, absorption, and membrane techniques is a crucial technology necessary to address current global warming issues. Porous media are essential for all these approaches and understanding the nature of the porous structure is important for achieving highly efficient CO2 adsorption. Porous carbon is considered to be a suitable porous media for investigating the fundamental mechanisms of CO2 adsorption, because of its simple morphology and its availability in a wide range of well-defined pore sizes. In this study, we investigated the dependence of CO2 adsorption on pore structures such as pore size, volume, and specific surface area. We also studied slit-shaped and cylindrical pore morphologies based on activated carbon fibers of 0.6–1.7 nm and carbon nanotubes of 1–5 nm, respectively, with relatively uniform structures. Porous media with larger specific surface areas gave higher CO2 adsorption densities than those of media having larger pore volumes. Narrower pores gave higher adsorption densities because of deep adsorption potential wells. However, at a higher pressure CO2 adsorption densities increased again in nanopores including micropores and small mesopores. The optimal pore size ranges of CO2 adsorption in the slit-shaped and cylindrical carbon pores were 0.4–1.2 and 1.0–2.0 nm, respectively, although a high adsorption density was only expected for the narrow carbon nanopores from adsorption potentials. The wider nanopore ranges than expected nanopore ranges are reasonable when considering intermolecular interactions in addition to CO2–carbon pore interactions. Therefore, cooperative adsorption among CO2 in relatively narrow nanopores can allow for high density and high capacity adsorption.

APA, Harvard, Vancouver, ISO, and other styles

29

Saeki, Tomonori, Kazuhito Hashimoto, Akira Fujishima, Naokazu Kimura, and Koji Omata. "Electrochemical Reduction of CO2 with High Current Density in a CO2-Methanol Medium." Journal of Physical Chemistry 99, no. 20 (May 1995): 8440–46. http://dx.doi.org/10.1021/j100020a083.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

ZHANG, WEI. "Density-driven enhanced dissolution of injected CO2 during long-term CO2 geological storage." Journal of Earth System Science 122, no. 5 (October 2013): 1387–97. http://dx.doi.org/10.1007/s12040-013-0342-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Cui, Leyu, Kun Ma, Maura Puerto, Ahmed A. Abdala, Ivan Tanakov, Lucas J. Lu, Yunshen Chen, et al. "Mobility of Ethomeen C12 and Carbon Dioxide (CO2) Foam at High Temperature/High Salinity and in Carbonate Cores." SPE Journal 21, no. 04 (August 15, 2016): 1151–63. http://dx.doi.org/10.2118/179726-pa.

Full text

Abstract:

Summary The low viscosity and density of carbon dioxide (CO2) usually result in the poor sweep efficiency in CO2-flooding processes, especially in heterogeneous formations. Foam is a promising method to control the mobility and thus reduce the CO2 bypass because of the gravity override and heterogeneity of formations. A switchable surfactant, Ethomeen C12, has been reported as an effective CO2-foaming agent in a sandpack with low adsorption on pure-carbonate minerals. Here, the low mobility of Ethomeen C12/CO2 foam at high temperature (120 °C), high pressure (3,400 psi), and high salinity [22 wt% of total dissolved solids (TDS)] was demonstrated in Silurian dolomite cores and in a wide range of foam qualities. The influence of various parameters, including aqueous solubility, thermal and chemical stability, flow rate, foam quality, salinity, temperature, and minimum-pressure gradient (MPG), on CO2 foam was discussed. A local-equilibrium foam model, the dry-out foam model, was used to fit the experimental data for reservoir simulation.

APA, Harvard, Vancouver, ISO, and other styles

32

Goede, Adelbert P. H. "CO2 neutral fuels." EPJ Web of Conferences 189 (2018): 00010. http://dx.doi.org/10.1051/epjconf/201818900010.

Full text

Abstract:

CO2 is a valuable resource, life on Earth depends on it. Rather than wasting it to the atmosphere, or burying it underground, CO2 can be combined with water and turned into valuable chemicals and fuels, the process being powered by renewable electricity. Renewable electricity generated by wind and photovoltaics (PV) is making big strides, but is limited by ill-matched supply and demand. In addition, electricity only makes up 20% to 30% of total energy demand. Domestic heating, high temperature/pressure Industrial processes and mobility/transportation gobble up the rest. Mobility and transportation prove particularly difficult to decarbonise. Aviation is a case in point. Battery-powered aircraft are unlikely to become feasible by 2050. Hydrogen has too low an energy density and is haunted by safety issues. Current policy, therefore, is directed at bio fuels. One problem, there is not enough of it. The Fuel vs. Food vs. Flora trilemma of bio-based fuel is unlikely to gain public acceptance. By converting renewable electricity into fuel, power to molecules (P2M), two birds are killed with one stone: providing fuel for long haul transportation and enabling long-term, large-scale energy storage to cover the seasonal mismatch between supply and demand of renewable electricity. Feedstock consists of air-captured carbon or nitrogen and water. Chemically combined, it creates a liquid fuel with greatly enhanced energy density, such as kerosene or ammonia, or gaseous fuel like methane which can replace natural gas in the existing gas network. Direct air capture of CO2 is currently being commercialised. The conversion technology of water and CO2 by electrolysis has recently been extended to novel plasma technology, the sub ject of this paper. For CO2 splitting by plasmolysis, the reduced electric field has been identified as the key parameter explaining and improving the energy efficiency. Energy efficiency by plasmolysis is similar to that of electrolysis, but offers advantages in energy density, upscaling and switching in response to intermittent power with no use of scarce material. A simple model explains the inverse relation between energy efficiency and particle conversion and relates input microwave power to CO2 gas density, plasma dimension and ionisation degree, allowing design parameters for a 100 kW pilot reactor to be specified. Recycling CO2 in combination with P2M is a game-changing technology to meet overall CO2 emission reduction targets. It takes advantage of existing, inexpensive infrastructure for energy storage, transport and distribution. Existing internal combustion engine technology can be maintained where necessary. Close coupled to a remote solar array or an off-shore wind farm it offers a solution to decentralised renewable fuel production at the renewable electricity source.

APA, Harvard, Vancouver, ISO, and other styles

33

Li, Ming, and Frank V. Bright. "Steady-State Fluorescence of Polystyrene Plasticized by Supercritical Carbon Dioxide." Applied Spectroscopy 50, no. 6 (June 1996): 740–46. http://dx.doi.org/10.1366/0003702963905736.

Full text

Abstract:

A steady-state fluorescence study of low-molecular-weight polystyrene (MW = 1060 g/mol and 13,000 g/mol) plasticized in supercritical CO2 is reported. In addition to excitation wavelength, molecular weight, and polystyrene concentration dependencies, CO2 density also strongly affects the emission spectral contours. A major increase in the steady-state fluorescence intensity and a significant decrease in the polystyrene 320- to 365-nm fluorescence intensity ratio are observed when CO2 density is increased. Concentration and conformational changes in the polystyrene molecules are used to explain the observations, and these results are proposed to arise from changes in the plasticization power of supercritical CO2 over the density range studied. A theoretical model is proposed that is based on the assumption that, at low CO2 densities and low polymer concentrations, polystyrene intermolecular interactions are negligible. The proposed model is able to fit our observed fluorescence data from a CO2 reduced density of 0.3 to 1.4.

APA, Harvard, Vancouver, ISO, and other styles

34

Shim, Hanseul, Sanghoon Lee, Jae Gang Kim, and Gisu Park. "CO₂ number density measurement in a shock tube with preheated carbon surface." Physics of Fluids 34, no. 6 (June 2022): 067105. http://dx.doi.org/10.1063/5.0095517.

Full text

Abstract:

The interaction between a heated carbon-based material and high-temperature air may produce ablation gas species such as CO2, affecting heat transfer onto the surface of a thermal protection system. The prediction of ablation gas production is critical for heat flux prediction and the design of a thermal protection system. In this study, we present a system that measures the number density of CO2 formed by the gas–surface interaction between a hot carbon surface and high-temperature gas. The heated carbon wall is exposed to high-temperature air by using a shock tube and surface heating model. The surface temperature of the carbon wall is measured using two-color ratio pyrometry. The number density of CO2 is predicted by performing numerical calculations for the shock tube flow with gas–surface interaction modeling. The number density of CO2 molecules is measured using infrared emission spectroscopy. The measured CO2 number density is 9.60 × 1023 m−3 at an area-weighted average surface temperature of 1212 K. The measured number density matches the predicted value within an error of 6%. The proposed system is applicable for CO2 number density measurement under various gas–surface interaction conditions, and it can be used for the investigation of ablative gas production and numerical research on gas–surface interactions.

APA, Harvard, Vancouver, ISO, and other styles

35

Rajab, Dr Muthenna Sh. "Root Caries Prevention Potential of Chopped CO2 Laser: an In Vitro Study." Mustansiria Dental Journal 5, no. 1 (March 27, 2018): 1–6. http://dx.doi.org/10.32828/mdj.v5i1.478.

Full text

Abstract:

The objective of this study aimed to assess the caries-preventive potential of various chopped CO2 laser parameters, and to explore the effect of the laser energy density on the caries inhibition activity.Roots of extracted human premolar teeth were irradiated with three various energy densities (25.47, 50.93, and 101.86) J/cm2, by changing the number of pulses, the pulse duration, and the spot diameter. The CO2 laser system emitted laser with 10.6m in wavelength. All roots were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The roots after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.Chopped CO2 laser preventive treatments inhibited carieslike lesion progression up to 36%. This effect was improved with decreased total energy density within the limits of the examined laser parameters.

APA, Harvard, Vancouver, ISO, and other styles

36

Van KLEUNEN, MARK, M. ANDRE STEPHAN, and BERNHARD SCHMID. "[CO2 ]- and density-dependent competition between grassland species." Global Change Biology 12, no. 11 (September 19, 2006): 2175–86. http://dx.doi.org/10.1111/j.1365-2486.2006.01248.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Ferdows, M., and M. Ota. "Density of CO2 Hydrate by Monte Carlo Simulation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220, no. 5 (May 1, 2006): 691–96. http://dx.doi.org/10.1243/09544062c13104.

Full text

Abstract:

In order to perform the density of CO2 hydrate, Monte Carlo simulations have been carried out under constant temperature and pressure conditions. The physical property of density have been focused for the clathrate hydrate of CO2: CO2.5.75H2O; CO2.7.67H2O at temperatures ranging from 150 to 280 K and pressure up to 10 Mpa in the number of particles, temperature, and pressure (NPT) ensemble using simple point charge (SPC) intermolecular potential model of water. Comparisons between Monte Carlo-calculated result SPC and the result calculated by transferable intermolecular potential (TIP4P) model are also presented.

APA, Harvard, Vancouver, ISO, and other styles

38

Zhang, Luning, Xuefeng Wang, and Qi-zong Qin. "Density functional calculations on the Zr–CO2 complexes." Journal of Molecular Structure: THEOCHEM 505, no. 1-3 (June 2000): 179–83. http://dx.doi.org/10.1016/s0166-1280(99)00375-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Song, Y., M. Nishio, B. Chen, S. Someya, and T. Ohsumi. "Measurement on CO2 solution density by optical technology." Journal of Visualization 6, no. 1 (March 2003): 41–51. http://dx.doi.org/10.1007/bf03180963.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Saberi Safaei, Tina, Adam Mepham, Xueli Zheng, Yuanjie Pang, Cao-Thang Dinh, Min Liu, David Sinton, Shana O. Kelley, and Edward H. Sargent. "High-Density Nanosharp Microstructures Enable Efficient CO2 Electroreduction." Nano Letters 16, no. 11 (October 17, 2016): 7224–28. http://dx.doi.org/10.1021/acs.nanolett.6b03615.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Badrutdinov, O. R., and M. Kh Salakhov. "Power density distribution of a commercial CO2 laser." Journal of Applied Spectroscopy 51, no. 5 (November 1989): 1152–55. http://dx.doi.org/10.1007/bf00664973.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Dai, Horng J., J. Michael Simonson, and Hank D. Cochran. "Density Measurements of Styrene Solutions in Supercritical CO2." Journal of Chemical & Engineering Data 46, no. 6 (November 2001): 1571–73. http://dx.doi.org/10.1021/je010116q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

WOODWARD, F. I., and C. K. KELLY. "The influence of CO2 concentration on stomatal density." New Phytologist 131, no. 3 (November 1995): 311–27. http://dx.doi.org/10.1111/j.1469-8137.1995.tb03067.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Romano, Valentino, Giovanna D’Angelo, Siglinda Perathoner, and Gabriele Centi. "Current density in solar fuel technologies." Energy & Environmental Science 14, no. 11 (2021): 5760–87. http://dx.doi.org/10.1039/d1ee02512k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

O'Neill, E. G., R. J. Luxmoore, and R. J. Norby. "Increases in mycorrhizal colonization and seedling growth in Pinusechinata and Quercusalba in an enriched CO2 atmosphere." Canadian Journal of Forest Research 17, no. 8 (August 1, 1987): 878–83. http://dx.doi.org/10.1139/x87-139.

Full text

Abstract:

Forest tree biomass is hypothesized to increase in a CO2-enriched atmosphere if mechanisms exist to ensure acquisition of limiting nutrients in forest soils. Investment of additional photosynthate produced at elevated CO2 into mycorrhizal proliferation and root growth may provide one such mechanism. To test this hypothesis, mycorrhizal density and seedling biomass were measured in shortleaf pine (Pinusechinata Mill.) and white oak (Quercusalba L.) grown in unfertilized forest soil in controlled-environment chambers at 360 μL L−1 and 700 μL L−1 CO2. Mycorrhizal density was greater at elevated CO2 in both species after 6 weeks of exposure; in white oak, the increased density persisted for 24 weeks. Root dry weight was increased 76% in P. echinata and 91% in Q. alba at 700 μL L−1 CO2; total seedling dry weight was increased by 66 and 56%, respectively. It is hypothesized that increased photosynthesis at elevated CO2 offsets the carbon requirement for mycorrhizal establishment on shortleaf pine. Greater mycorrhizal density and enhanced 1st-year root growth in both species may facilitate future nutrient acquisition, supporting further biomass increases in an enriched CO2 atmosphere.

APA, Harvard, Vancouver, ISO, and other styles

46

Hunt, Lena, Michal Fuksa, Karel Klem, Zuzana Lhotáková, Michal Oravec, Otmar Urban, and Jana Albrechtová. "Barley Genotypes Vary in Stomatal Responsiveness to Light and CO2 Conditions." Plants 10, no. 11 (November 21, 2021): 2533. http://dx.doi.org/10.3390/plants10112533.

Full text

Abstract:

Changes in stomatal conductance and density allow plants to acclimate to changing environmental conditions. In the present paper, the influence of atmospheric CO2 concentration and light intensity on stomata were investigated for two barley genotypes—Barke and Bojos, differing in their sensitivity to oxidative stress and phenolic acid profiles. A novel approach for stomatal density analysis was used—a pair of convolution neural networks were developed to automatically identify and count stomata on epidermal micrographs. Stomatal density in barley was influenced by genotype, as well as by light and CO2 conditions. Low CO2 conditions resulted in increased stomatal density, although differences between ambient and elevated CO2 were not significant. High light intensity increased stomatal density compared to low light intensity in both barley varieties and all CO2 treatments. Changes in stomatal conductance were also measured alongside the accumulation of pentoses, hexoses, disaccharides, and abscisic acid detected by liquid chromatography coupled with mass spectrometry. High light increased the accumulation of all sugars and reduced abscisic acid levels. Abscisic acid was influenced by all factors—light, CO2, and genotype—in combination. Differences were discovered between the two barley varieties: oxidative stress sensitive Barke demonstrated higher stomatal density, but lower conductance and better water use efficiency (WUE) than oxidative stress resistant Bojos at saturating light intensity. Barke also showed greater variability between treatments in measurements of stomatal density, sugar accumulation, and abscisic levels, implying that it may be more responsive to environmental drivers influencing water relations in the plant.

APA, Harvard, Vancouver, ISO, and other styles

47

Mehana, Mohamed, Mashhad Fahes, and Liangliang Huang. "The Density of Oil/Gas Mixtures: Insights From Molecular Simulations." SPE Journal 23, no. 05 (March 7, 2018): 1798–808. http://dx.doi.org/10.2118/187297-pa.

Full text

Abstract:

Summary Gravity segregation of reservoir fluids is mainly controlled by density. Although most gases used in the field for enhanced oil recovery (EOR) result in a reduction in density upon mixing with the oil, carbon dioxide (CO2) can result in an increase of the density upon mixing. Experimental observations confirmed this behavior. In addition, field operations report an early breakthrough for CO2 flooding, which is related to the associated gravity segregation caused by the abnormal density behavior. However, the molecular interactions at play that have an impact on the observed macroscopic behavior have not been well-understood or deeply investigated. Molecular simulation of methane, propane, and CO2 mixtures with octane, benzene, pentane, and hexadecane is studied up to the miscibility limit at temperatures up to 260°F (400 K), and pressures up to 6,000 psi (400 bar). There is a proximity between the values of density obtained through molecular simulations and those obtained through experimental work and equation-of-state (EOS) methods. It is evident that oil/CO2 mixtures sustain their density to a higher gas mole percentage compared with other gases, with the density in some cases exceeding the pure liquid-hydrocarbon density even when gas density at those conditions is lower. Our results have demonstrated that the proposed mechanisms in literature—namely, intermolecular Coulombic and induced dipole interactions and the stretching of the alkane molecules—might not be the key to understanding the oil/CO2 density behavior. However, the molecular size of the gas seems to play an important role in the density profile observed.

APA, Harvard, Vancouver, ISO, and other styles

48

Wu, Jialong, Qinmin Pan, and Garry L. Rempel. "Pressure−Density−Temperature Behavior of CO2/Acetone, CO2/Toluene, and CO2/Monochlorobenzene Mixtures in the Near-Critical Region." Journal of Chemical & Engineering Data 49, no. 4 (July 2004): 976–79. http://dx.doi.org/10.1021/je0342771.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Yan, Xupeng, Chunjun Chen, Yahui Wu, Shoujie Liu, Yizhen Chen, Rongjuan Feng, Jing Zhang, and Buxing Han. "Efficient electroreduction of CO2 to C2+ products on CeO2 modified CuO." Chemical Science 12, no. 19 (2021): 6638–45. http://dx.doi.org/10.1039/d1sc01117k.

Full text

Abstract:

CO₂ can be efficiently converted into C₂₊ products on CeO₂ modified CuO catalysts and the faradaic efficiency could reach 75.2% with a current density of 1.21 A cm⁻².

APA, Harvard, Vancouver, ISO, and other styles

50

Li, Qian, Weihua Cai, Xiaojing Tang, Yicheng Chen, Bingxi Li, and Ching-Yao Chen. "The impact of heterogeneous anisotropy of porous media on density-driven convection." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 2 (September 26, 2019): 956–76. http://dx.doi.org/10.1108/hff-04-2019-0276.

Full text

Abstract:

Purpose The aim of this study is to numerically simulate the density-driven convection in heterogeneous porous media associated with anisotropic permeability field, which is important to the safe and stable long term CO2 storage in laminar saline aquifers. Design/methodology/approach The study uses compact finite difference and the pseudospectral method to solve Darcy’s law. Findings The presence of heterogeneous anisotropy may result in non-monotonic trend of the breakthrough time and quantity of CO2 dissolved in the porous medium, which are important to the CO2 underground storage. Originality/value The manuscript numerically study the convective phenomena of mixture contained CO2 and brine. The phenomena are important to the process of CO2 enhanced oil recovery. Interesting qualitative patterns and quantitative trends are revealed in the manuscript.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'CO2 density'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles