Ab-Initio Molecular Dynamics investigation of gas adsorption on α-quartz (001) for CO2 enhanced natural gas recovery

Goal, Scope and Backgound Historically, landfills have been the simplest form of eliminating urban solid waste with the minimum cost. They have been the most usual method for discarding solid waste. However, landfills are considered authentic biochemical reactors that introduce large amounts of contaminants into the environment in the form of gas and leachates. The dynamics of generation and the movement of gas in landfills depend on the input and output parameters, as well as on the structure of the landfill and the kind of waste. The input parameters include water introduced through natural or artificial processes, the characteristics of the urban solid waste, and the input of atmospheric air. The main output parameters for these biochemical reactors include the gases and the leachates that are potentially pollutants for the environment. Control systems are designed and installed to minimize the impact on the environment. However, these systems are not perfect and a significant amount of landfill gas could be released to the atmosphere through the surface in a diffuse form, also known as Non-controlled emission. In this paper, the results of the Non-controlled biogenic gas emissions from the Lazareto landfill in Tenerife, Canary Islands, are presented. The purpose of this study was to evaluate the concentration of CH4 and CO2 in the soil gas of the landfill cover, the CH4 and CO2 efflux from the surface of the landfill and, finally, to compare these parameters with other similar landfills. In this way, a better understanding of the process that controls biogenic gas emissions in landfills is expected.

Decrease in rubisco activation at high CO2 concentration was caused by decrease in carbamylation of rubisco (Rohet al., 1996). However, it is unclear whether decrease in carbamylation rate at high CO2 concentration is due to decrease in activity itself or content of rubisco activase. To clarify this ambiguity, investigation was performed to determine effects of CO2 concentration on rubisco activase with kidney bean (Phaseolus vulgaris L.) leaves grown at normal CO2 (350 ppm) and high CO2 (650 ppm) concentration. The analysis of Western blotting showed that the 50 and 14.5 kl) polypeptides were identified immunochemically as the large and small subunits of rubisco in the preparation, respectively. For the 14.5 kD small subunit, the degree of intensity at high CO2 concentration was similar to that at normal CO2 concentration. For the 50 kD large sububit, however, the intensity of a band at high CO, concentration was significantly higher than that at normal CO2 concentration, indicating that only the large subunit is affected by high CO2 concentration. The analysis of Western immunoblotting showed two major polypeptides at 46 and 42 kD which were identified as rubisco activase subunits. The intensities of two bands were shown to be higher at normal CO2 than high CO2 concentration. These data indicate that decrease of carbamylation resulting from increase of CO2 concentration was caused by rubisco activase. Finally, by employing ATP hydrolysis assay and ELISA, we also observed a significant decrease in both activity and content of rubisco activase as CO2 concentration was raised from normal to high CO2 concentration. These results suggest that decrease in rubisco carbamylation at high CO2 concentration is caused by activity itself and/or content of rubisco activase.

Global climate changes may impact the growth and management of weed species. The aim of this work was to evaluate the impact of recent climate changes on the growth of weeds and herbicide efficacy. The effects of temperature, carbon dioxide (CO2 ), and herbicide on growth and control of Bromus tectorum L., Hordeum murinum L., and Lactuca serriola L. were studied. Treatments included: control or ambient environment (CO2 concentration 400-450 ppm; temperature 20/10 °C day/night); elevated temperature (CO2 concentration 400-450 ppm; temperature 25/15 °C day/night); high CO2 and elevated temperature (CO2 concentration 800-900 ppm; temperature 25/15 °C day/night); high CO2 (CO2 concentration 800-900 ppm; temperature 20/10 °C day/night). Glyphosate rates (active ingredient) used in the experiment were: 0 g ha-1 (untreated control); 360 g ha-1 ; 720 g ha-1 ; 1080 g ha-1 ; 1440 g ha-1 (recommended rate), and 2880 g ha-1 . High CO2 concentration and high CO2 concentration plus high temperature improved the biomass and growth parameters of weeds in the studies. In general, high temperature had a neutral, negative or slightly positive effect on the growth of weed species. Climatic conditions did not affect the activity of glyphosate; its application provided equal and effective weed control under both CO2 and temperature levels and their combinations. The positive effect of high CO2 concentration on the growth of weeds does not impact the activity of glyphosate. © 2017 Society of Chemical Industry.

The extraction of methane from its hydrates using carbon dioxide involves the decomposition of the hydrate resulting in a CH4-CO2-H2O ternary solution. Using classical molecular dynamics simulations, we investigate the evolution of dissolved gas molecules in the ternary system at different concentrations of CO2. Various compositions considered in the present study resemble the solution formed during the decomposition of methane hydrates at the initial stages of the extraction process. We find that the presence of CO2 aids the formation of CH4 bubbles by causing its early nucleation. Elucidation of the composition of the bubble revealed that in ternary solutions with high concentration of CO2, mixed gas bubbles composed of CO2 and CH4 are formed. To understand the role of CO2 in the nucleation of CH4 bubbles, the structure of the bubble formed was analyzed, which revealed that there is an accumulation of CO2 at the interface of the bubble and the surrounding water. The aggregation of CO2 at the bubble-water interface occurs predominantly when the concentration of CO2 is high. Radial distribution function for the CH4-CO2 pair indicates that there is an increasingly favorable direct contact between dissolved CH4 and CO2 molecules in the bubble-water interface. It is also observed that the presence of CO2 at the interface results in the decrease in surface tension. Thus, CO2 leads to greater stability of the bubble-water interface thereby bringing down the critical size of the bubble nuclei. The results suggest that a rise in concentration of CO2 helps in the removal of dissolved CH4 thereby preventing the accumulation of methane in the liquid phase. Thus, the presence of CO2 is predicted to assist the decomposition of methane hydrates in the initial stages of the replacement process.

The ultramafic-hosted Kairei vent field is located at 25°19′ S, 70°02′ E, towards the Northern end of segment 1 of the Central Indian Ridge (CIR-S1) at a water depth of ~2450 m. This study aims to investigate the distribution of trace elements among sulfide minerals of differing textures and to examine the possible factors controlling the trace element distribution in those minerals using LA-ICP-MS spot and line scan analyses. Our results show that there are distinct systematic differences in trace element distributions throughout the different minerals, as follows: (1) pyrite is divided into three types at Kairei, including early-stage euhedral pyrite (py-I), sub-euhedral pyrite (py-II), and colloform pyrite (py-III). Pyrite is generally enriched with Mo, Au, As, Tl, Mn, and U. Pyrite-I has high contents of Se, Te, Bi, and Ni when compared to the other types; py-II is enriched in Au relative to py-I and py-III, but poor in Ni; py-III is enriched in Mo, Pb, and U but is poor in Se, Te, Bi, and Au relative to py-I and py-II. Variations in the concentrations of Se, Te, and Bi in pyrite are most likely governed by the strong temperature gradient. There is generally a lower concentration of nickel than Co in pyrite, indicating that our samples precipitated at high temperatures, whereas the extreme Co enrichment is likely from a magmatic heat source combined with an influence of serpentinization reactions. (2) Chalcopyrite is characterized by high concentrations of Co, Se, and Te. The abundance of Se and Te in chalcopyrite over the other minerals is interpreted to have been caused by the high solubilities of Se and Te in the chalcopyrite lattice at high temperatures. The concentrations of Sb, As, and Au are relatively low in chalcopyrite from the Kairei vent field. (3) Sphalerite from Zn-rich chimneys is characterized by high concentrations of Sn, Co, Ga, Ge, Ag, Pb, Sb, As, and Cd, but is depleted in Se, Te, Bi, Mo, Au, Ni, Tl, Mn, Ba, V, and U in comparison with the other minerals. The high concentrations of Cd and Co are likely caused by the substitution of Cd2+ and Co2+ for Zn2+ in sphalerite. A high concentration of Pb accompanied by a high Ag concentration in sphalerite indicates that Ag occurs as Pb–Ag sulfosalts. Gold is generally low in sphalerite and strongly correlates with Pb, suggesting its presence in microinclusions of galena. The strong correlation of As with Ge in sphalerite from Kairei suggests that they might precipitate at medium temperatures and under moderately reduced conditions. (4) Bornite–digenite has very low concentrations of most trace elements, except for Co, Se, and Bi. Serpentinization in ultramafic-hosted hydrothermal systems might play an important role in Au enrichment in pyrite with low As contents. Compared to felsic-hosted seafloor massive sulfide deposits, sulfide minerals from ultramafic-hosted deposits show higher concentrations of Se and Te, but lower As, Sb, and Au concentrations, the latter often attributed to the contribution of magmatic volatiles. As with typical ultramafic-hosted seafloor massive sulfide deposits, Se enrichment in chalcopyrite from Kairei indicates that the primary factor that controls the Se enrichment is temperature-controlled mobility in vent fluids.

To study the effects of carbon dioxide insufflation pressure and concentration on the adhesion, growth, apoptosis, and necrosis of transitional-cell carcinoma (TCC). Adhesion and growth of the AY-27 rat TCC cell line was measured after CO2 insufflation in vitro at different pressures ranging from 0 to 15 mm Hg and after incubation in CO2-air mixtures at 5%, 10%, and 15% CO2 by volume. Tumor adhesion decreased significantly after CO2 insufflation. For all insufflation pressures, there was an increase in cell growth, apoptosis, and necrosis for the first 24 hours followed by a steady decline. High concentrations of CO2 (>5%) inhibited cell growth for only the first 48 hours. The effects of CO2 pneumoperitoneum on tumor-cell adhesion, growth inhibition, apoptosis, and necrosis were more prominent at high CO2 pressure (> or =15 mm Hg) and concentration (>5% CO2). However, insufflation pressure had a greater inhibitory effect on tumor growth than did CO2 concentration. High insufflation pressures and CO2 concentrations significantly decreased extracellular pH. The short-term effect of CO2 on TCC growth and apoptosis is complex. Overall, CO2 has a toxic effect on TCC and inhibits cell adhesion and growth. High CO2 concentrations (>5%) and high insufflation pressures (> or =15 mm Hg) are most effective in decreasing tumor-cell adhesion and growth.

A theoretical study of gas adsorption on α-quartz (0 0 1) for CO2 enhanced natural gas recovery

The course of respiration and circulation in death by carbon dioxide poisoning

ABSTRACTElevator evacuation has attracted increasing attention as an efficient transport method in high-rise buildings, which is one of the most complex and interesting areas of modern fire research. Through a 3D numerical model built from ANSYS Fluent, this paper studied the influence of elevator motion on the gas characteristics as well as the effectiveness of the smoke control system in the lobby during elevator evacuation in a high-rise building fire. Pressure distribution, temperature distribution and CO concentration distribution in the elevator lobby were analyzed. It was found that the elevator motion decreased the pressure in the elevator lobby while increased the temperature and CO concentration, which indicated that more fire smoke had spread into the lobby when the elevators moved and the effectiveness of the smoke control systems had been weaken. When the elevator velocity was increased from 0 m/s to 2 m/s, the lowest pressure in the lobby was decreased by 566.7%; the temperature line was mostly above the line representing the still elevator; the CO concentration experienced the most change at the height of 2 m: the highest CO concentration was, respectively, increased by 30.4% and 26.7% when the air supply volume (qs) was 0 m3/h and 20000 m3/h. As the air supply volume in the lobby increased, the pressure was increased while the temperature and the CO concentration was decreased. Changes of temperature lines and CO concentration lines under various air supply volumes were very similar. When qs was increased from 0 m3/h to 20000 m3/h, the pressure in the lobby was increased from 0 Pa to around 8 Pa, the highest temperature and CO concentration were decreased by 23.8% and 87.5%, respectively.

Sphalerite from the sediment-hosted Dolostone Ore Formation (DOF) Cu-Co-Zn deposit, in northwestern Namibia, has previously been shown to contain extremely high concentrations of the critical metal Co (up to 1 wt%). These concentrations are the highest reported in sphalerite to date, and the how and why of sphalerite being able to incorporate such high concentrations of Co are poorly understood. We use correlative electron probe microanalysis, electron backscattered diffraction, and atom probe to reconstruct the likely incorporation mechanisms and modes of occurrence of such high Co concentrations in natural sphalerite. While over twenty samples were studied, the comprehensive analytical workflow was executed on one representative sample to gain a detailed understanding of Co enrichment. The sulfides of the studied sample are Co-rich pyrite, chalcopyrite, Co-rich sphalerite, linnaeite, cobaltpentlandite, and cobaltite, mentioned in order of abundance. Detailed petrography of these sulfides indicates that they formed through three stages during the main Cu-Co-Zn ore stage of the DOF. Cobalt was initially contained in pyrite that grew during Ore Stage 1 and was later affected by oxidizing fluids (Ore Stage two). This led to remobilization and growth of linnaeite (Co2+Co3+2S4). A later change in fO2 (Ore Stage three) led to the breakdown of linnaeite and the further growth of accessory cobaltite along with the Co-rich sphalerite and chalcopyrite. The hyper-enriched Co-sphalerite then is the last major sink for Co in the DOF deposit. A low Fe and Co and high Zn sub-grain boundary network within the Co-rich sphalerite was identified by EPMA and EBSD. This sub-grain network is believed to have formed during a later, secondary metamorphic stage (Cu-Zn (-Pb) Ore Stage 4), which developed during ductile deformational mineralization styles such as pressure shadows and veins. Our APT data reconstructions show no evidence for Co-inclusions within the Co-sphalerite, and spatial ion correlation analyses of the data suggest that Co occurs in the sphalerite through simple substitution of Zn. This study demonstrates that sphalerite may contain significant concentrations of the Co through simple substitution, potentially representing an important non-traditional Co source in future critical metal exploration.

Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas contributing to global climate change. SCIAMACHY on board ENVISAT (launched in 2002) is the first satellite instrument to monitor the changes in CO2 concentration in the lowest atmospheric layers. The temporal and spatial distribution of CO2 (2003–2009) concentration based on SCIAMACHY over China is presented and discussed. It shows an annual increase and a seasonal cycle. The CO2 annual growth rate was about 1.8 ppm year−1, with the highest value being in spring and the lowest in autumn. The CO2 concentration variation is determined by many complex factors. In this article, we analyse the important factors affecting CO2 variations, with special emphasis on terrestrial ecosystems and energy consumption. Terrestrial ecosystems are an important sink in the global carbon cycle. The relationship between CO2 concentration and Moderate Resolution Imaging Spectroradiometer (MODIS) net primary production (NPP) in 2008 is analysed. CO2 concentration is inversely proportional to NPP both in regions with high-density vegetation and in deserts. The Yunnan province has the highest NPP value and the lowest CO2 concentration, whereas the Takla Makan Desert has the lowest NPP value and the highest CO2 concentration. Energy consumption is the main emission source of atmospheric CO2. CO2 emissions from energy consumption show a steady increase in China since 1980. China's CO2 concentration variation shows a high correlation with energy consumption (coefficient of determination (R 2) > 0.8). The regions with high energy consumption are major industrial regions such as Shandong, Guangdong, Jiangsu, Zhejiang, Hebei, and Henan.

Crop plants at the 5 to 7-leaf stages possessing C3 (barley, rice, and soybean) and C4 (barnyard millet and maize) pathways of photosynthesis were cultured for 15 days in transparent growth chambers placed outdoors under 4 different carbon dioxide (CO2) concentrations from 1/2 to 10 times the normal atmosphere (ca. 350 ppm) to make clear the effects of various CO2 concentrations on growth and dry matter production. The following results were obtained: I. Increases in plant height and leaf area were promoted by high CO2 concentrations, but the degree of promotion was relatively small. At a low concentration (160 ppm), plants often elongated and had narrow drooping leaves as compared to control plants under normal CO3 concentration. 2. Increase in dry weight was promoted by high CO2 concentrations and suppressed by a low concentration. This increase proceeded up to about 3 times (sometimes 10 times) the normal concentration, and this was effected mainly through the increase in net assimilation rate. The C3- and C4-plants responded differently to CO2 concentrations, the latter giving less suppression at a low concentration and less promotion at high concentrations than the former. 3. Tillering in barley and rice was accelerated by high CO2 concentratoins and withheld by a low concentration. In rice plants, observed at the 7-leaf stage, the promotion of tillering took place at the 4th node, and the appearance of tillers was made steadier at the 2nd and 3rd nodes by high CO2 concentrations. 4. Distribution ratio of dry matter in rice and maize was in a marked contrast. In rice plant distribution to leaves was less and that to roots was increased at high CO2 concentrations, while in maize such a tendency was not observed at all. 5. Transpiration rates (dm-2 day-1) were smaller at higher CO2 concentrations. At a low concentration, the promotion of transpiration was enhanced day by day as the treatment proceeded. On fine days, the leaf temperature was about 1°C lower at a low CO2 concentration and about 1°C higher at higher concentrations as compared to control plot, but no difference was observed on cloudy days.

The effects of elevated CO 2 concentration on the growth and development of the funnel‐web weaving spider A gelena labyrinthica ( C lerck) ( A raneae: A gelenidae) were studied in climate chambers with low (370 μl l −1 ) or high (750 μl l −1 ) CO 2 concentration. Seventh‐instar A . labyrinthica cultured under each of these CO 2 concentrations were randomly selected to determine nutrient composition (total protein, total amino acid, and free fatty acid) and digestive or detoxification enzymes activity (peroxidase, amylase, and superoxide dismutase) using test kits. When reared under high CO 2 concentration, total development of A . labyrinthica was significantly faster. Carapace length and width and body weight did not differ between CO 2 concentrations, nor the levels of protein and total amino acids in seventh‐instar A . labyrinthica . However, free fatty acid levels were significantly lower under high CO 2 concentration. Specific activities of peroxidase and superoxide dismutase in seventh‐instar A . labyrinthica did not differ between CO 2 concentrations. The specific activity of amylase under high CO 2 concentration was higher than that of the low CO 2 group. The effects of elevated CO 2 on A . labyrinthica varied from those on the wandering spider P ardosa astrigera L Koch, as found in an earlier study. Apparently, elevated CO 2 has a species‐specific impact on spiders.

Phase equilibria, thermodynamic properties, and solubility of quartz in saline-aqueous-carbonic fluids: Application to orogenic and intrusion-related gold deposits

Computational analysis of feasibility of methane displacement by carbon dioxide during enhanced gas recovery from calcite-rich shale