Effects Of CO2 Research Articles

Fossil Energy Consumption, Carbon Dioxide Emissions and Adult Mortality Rate in Nigeria

The health implications of fossil energy consumption and carbon dioxide(CO2) emissions remain a global concern. This study examines the effectof fossil energy consumption and CO2 emissions on adult mortality rate inNigeria. The study relies on the Health Production Function and utilisesthe Autoregressive Distributed Lag technique to analyse time series datafrom 1980 to 2019. The results of the estimated model show that fossil energyconsumption reduces adult mortality rates in the short run, while co2emissions increase adult mortality rates both in the short and long run.In addition, government health expenditure follows an inverted U-shaperelationship in explaining adult mortality while foreign direct investmenthas a U-shape relationship with adult mortality in Nigeria. Trade opennessand monetary policy are insignificant in the short and long run. Itis recommended that the government should substitute clean energy forfossil fuel energy to improve the quality of life, strengthen CO2 emissionstax and ensure health funds are used for the improvement of healthcareservice delivery in Nigeria.

RSM for Modelling the CO2 Effect in the Interfacial Tension Between Brine and Waxy Dulang Crude Oil During LSW-WAG EOR

Recent studies on low-salinity waterflooding (LSW) and CO2 water-alternating gas (WAG) use are noteworthy because of their effectiveness in recovered oil content retention in mature fields. s the brine salinity decreases, the solubility of CO2also increases. The CO2in the injected water is expected to reduce the water/oil interfacial tension (IFT), and thus previouslytrapped oil in the rock by capillary forces will flow. However, as of yet, a fewresearches havefocusedon the fluid/fluidinteraction involving waxy crude oil/brinein the LSW-WAGprocess. Twomodels, both of which have been developed from experimental interfacial tension measurements, assist in estimating the CO2's effect on oil/water interfacial tension in the presence and absence of CO2. This objective is accomplished by designing experiments using the modified central composite design (CCD)method in response surface methodology (RSM). Theeffectof pressure, brine salinity, and CO2on oil/water IFT are taken into consideration while modelling.Analysis of variance (ANOVA) was used to determine the optimal values of input variables based on the developed model to obtain an acceptable model. The R-squared values indicate that the developed models arecapable of accurately forecasting the experimental results of oil/water IFT using Dulang crude oil and seven different brine salinities. The findings of this study are expected to shed light on the fluid/fluid interaction behaviour during the LSW-WAG recovery process in a mature field producing waxy crude oil.

Precipitation alters the CO2 effect on water-use efficiency of temperate forests.

Increasing water-use efficiency (WUE), the ratio of carbon gain to water loss, is a key mechanism that enhances carbon uptake by terrestrial vegetation under rising atmospheric CO2 (ca ). Existing theory and empirical evidence suggest a proportional WUE increase in response to rising ca as plants maintain a relatively constant ratio between the leaf intercellular (ci ) and ambient (ca ) partial CO2 pressure (ci /ca ). This has been hypothesized as the main driver of the strengthening of the terrestrial carbon sink over the recent decades. However, proportionality may not characterize CO2 effects on WUE on longer time-scales and the role of climate in modulating these effects is uncertain. Here, we evaluate long-term WUE responses to ca and climate from 1901 to 2012 CE by reconstructing intrinsic WUE (iWUE, the ratio of photosynthesis to stomatal conductance) using carbon isotopes in tree rings across temperate forests in the northeastern USA. We show that iWUE increased steadily from 1901 to 1975 CE but remained constant thereafter despite continuously rising ca . This finding is consistent with a passive physiological response to ca and coincides with a shift to significantly wetter conditions across the region. Tree physiology was driven by summer moisture at multi-decadal time-scales and did not maintain a constant ci /ca in response to rising ca indicating that a point was reached where rising CO2 had a diminishing effect on tree iWUE. Our results challenge the mechanism, magnitude, and persistence of CO2 's effect on iWUE with significant implications for projections of terrestrial productivity under a changing climate.

Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs

Abstract. Anthropogenic warming has been projected to increase global drought for the 21st century when calculated using traditional offline drought indices. However, this contradicts observations of the overall global greening and little systematic change in runoff over the past few decades and climate projections of future greening with slight increases in global runoff for the coming century. This calls into question the drought projections based on traditional offline drought indices. Here we calculate a widely used traditional drought index (i.e., the Palmer Drought Severity Index, PDSI) using direct outputs from 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models (PDSI_CMIP5) such that the hydrologic consistency between PDSI_CMIP5 and CMIP5 models is maintained. We find that the PDSI_CMIP5-depicted drought increases (in terms of drought severity, frequency, and extent) are much smaller than that reported when PDSI is calculated using the traditional offline approach that has been widely used in previous drought assessments under climate change. Further analyses indicate that the overestimation of PDSI drought increases reported previously using the PDSI is primarily due to ignoring the vegetation response to elevated atmospheric CO2 concentration ([CO2]) in the traditional offline calculations. Finally, we show that the overestimation of drought using the traditional PDSI approach can be minimized by accounting for the effect of CO2 on evapotranspiration.

Effects of CO2 Addition on the Turbulent Flame Front Dynamics and Propagation Speeds of Methane/Air Mixtures

Exhaust gas recirculation (EGR) is one of the most promising methods of improving the performance of power-generating gas turbines. CO2 is known to have the largest impact on flame behavior of any major exhaust species, but few studies have specified its thermal, kinetic, and transport effects on turbulent flames. Therefore, in this study, methane/air mixtures diluted with CO2 are experimentally investigated in a reactor-assisted turbulent slot (RATS) burner using OH planar laser-induced fluorescence (PLIF) measurements. CO2 addition is tested under both constant adiabatic flame temperature and variable adiabatic flame temperature conditions in order to elucidate its thermal, kinetic, and transport effects. Particular attention is paid to CO2's effects on the flame surface density, progress variable, turbulent burning velocity, and flame wrinkling. The experimental measurements reveal that CO2's thermal effects are the dominant factor in elongating the turbulent flame brush and decreasing the turbulent burning velocity. When thermal effects are removed by holding the adiabatic flame temperature constant, CO2's kinetic effects are the next most important factor, producing an approximately 5% decrease in the global consumption speed for each 5% of CO2 addition. The transport effects of CO2, however, tend to increase the global consumption speed, counteracting 30–50% of the kinetic effects when the adiabatic flame temperature is fixed. It is also seen that CO2 addition increases the normalized global consumption speed primarily through an enhancement of the stretch factor.

Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties

A series of Zn1−xCoxO nanorods with dopant content ranging fromx = 0.00 to 0.10 was prepared by a wet chemical method. AllZn1−xCoxO samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersionx-ray line mapping analysis, and UV–visible absorption spectroscopy. It was found thatCo2+ ions were homogeneouslysubstituted for Zn2+ ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effectof Co2+ doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation.Co2+ ions acted as the trapping or recombination centers for electrons and holes, leading to areduction in photodegradation efficiency under UV light illumination. Alternatively,Co2+ ions enhanced the optical absorption and produced the photoinduced carriersunder visible illumination in terms of two charge transfer transitions involvingCo2+ ions.Consequently, Co2+ ions substituted in the lattice of ZnO nanorods significantly improved the visible lightphotocatalytic activity.

CO adsorption effects on the electronic properties of Fe tape-porphyrin

We investigated the electronic properties of Fe tape-porphyrin and the effectof CO adsorption on it within the framework of density functional theory. Asfor the numerical results, we found that the Fe tape-porphyrin is metallic,and that the CO-adsorbed Fe tape-porphyrin is an insulator. Comparing theelectronic structures of the Fe porphyrin molecule and the CO-adsorbed one, wefound that the metal–insulator transition is caused by the hybridization of thedxz anddyz orbitals ofFe with the πg* orbital of CO.

Cobalt ions inhibit negative feedback in the outer retina by blocking hemichannels on horizontal cells

In goldfish, negative feedback from horizontal cells to cones shifts the activation function of the Ca2+ current of the cones to more negative potentials. This shift increases the amount of Ca2+ flowing into the cones, resulting in an increase in glutamate release. The increased glutamate release forms the basis of the feedback-mediated responses in second-order neurons, such as the surround-induced responses of bipolar cells and the spectral coding of horizontal cells. Low concentrations of Co2+ block these feedback-mediated responses in turtle retina. The mechanism by which this is accomplished is unknown. We studied the effects of Co2+ on the cone/horizontal network of goldfish retina and found that Co2+ greatly reduced the feedback-mediated responses in both cones and horizontal cells in a GABA-independent way. The reduction of the feedback-mediated responses is accompanied by a small shift of the Ca2+ current of the cones to positive potentials. We have previously shown that hemichannels on the tips of the horizontal cell dendrites are involved in the modulation of the Ca2+ current in cones. Both the absence of this Co2+-induced shift of the Ca2+ current in the absence of a hemichannel conductance and the sensitivity of Cx26 hemichannels to low concentrations of Co2+ are consistent with a role for hemichannels in negative feedback from horizontal cells to cones.

Comparison of Agricultural Impacts of Climate Change Calculated from High and Low Resolution Climate Change Scenarios: Part I. The Uncertainty Due to Spatial Scale

We investigated the effect of two different spatial scales of climate change scenarios on crop yields simulated by the EPIC crop model for corn, soybean, and wheat, in the central Great Plains of the United States. The effect of climate change alone was investigated in Part I. In Part II (Easterling et al., 2001) we considered the effects ofCO2 fertilization effects and adaptation in addition to climate change. The scenarios were formed from five years of control and 2 ×CO2 runs of a high resolution regional climate model (RegCM) and the same from an Australian coarse resolution general circulation model (GCM), which provided the initial and lateral boundary conditions for the regional model runs. We also investigated the effect of two different spatial resolutions of soil input parameters to the crop models. We found that for corn and soybean in the eastern part of the study area, significantly different mean yield changes were calculated depending on the scenario used. Changes in simulated dryland wheat yields in the western areas were very similar, regardless of the scale of the scenario. The spatial scale of soils had a strong effect on the spatial variance and pattern of yields across the study area, but less effect on the mean aggregated yields. We investigated what aspects of the differences in the scenarios were most important for explaining the different simulated yield responses. For instance, precipitation changes in June were most important for corn and soybean in the eastern CSIRO grid boxes. We establish the spatial scale of climate changescenarios as an important uncertainty for climate change impacts analysis.

Yield and partitioning in crops of contrasting cultivars of winter wheat in response to CO2 and temperature in field studies using temperature gradient tunnels

Diverse cultivars of winter wheat (Triticum aestivum L.) were grown in the field in 1993/94 and 1994/95 at Reading UK in temperature gradient tunnels at normal atmospheric (c. 370) or elevated CO2 concentration (c. 700 μmol CO2 mol−1 air). In 1993/94, grain yield of cv. Avalon was insensitive to mean temperature (between 8·8 and 10·9°C), while elevated CO2 increased yield by 1·3 t ha−1 (12·6%). In all other cultivars, warming reduced grain yield and CO2 increased grain yield. In 1993/94, in cvs Galahad and Mercia the effects of CO2 and temperature on yield were additive. However, for cv. Hereward in both years and for cv. Soissons in 1994/95, there were negative interactions between the effects of CO2 and temperature on yield: the maximum benefit of doubling CO2 to grain yield, 4·5 and 2·7 t ha−1 (65 and 29%) respectively, occurred at cooler temperatures; there was no benefit from doubling CO2 (i.e. 0%) once the temperature had increased above the seasonal mean by 2·2–2·6°C in cv. Hereward and by 1·3°C in cv. Soissons. The beneficial effect of doubling CO2 on grain yield in cvs Galahad, Hereward, Mercia and Soissons was negated by an increase in mean seasonal temperature of only 0·7–2·0°C. Warming decreased root dry mass at anthesis in 1994/95 while it increased at elevated CO2 (49 and 186%, coolest and warmest regime, respectively). Carbon partitioned to roots declined progressively with warming, while at elevated CO2 there was an average of 56% increase in allocation to roots. The relative impacts of both CO2 and temperature were greater on root dry mass than on either grain yield or total above-ground biomass, while the effects on grain and biomass yield varied considerably between cultivars, suggesting that the impact of rising CO2 and temperature are likely to be dependent on cultivar.

The influence of atmospheric CO2 concentration on the protein, starch and mixing properties of wheat flour

Wheat (Triticum aestivum L.) cultivars Hartog and Rosella were grown at CO2 concentrations of 280 µL L-1 (representing the pre-industrial CO2 concentration), 350 µL L-1 (ambient) and 900 µL L-1 (an extreme projection of atmospheric CO2 concentration). The plants were grown in naturally lit glasshouses in 7 L pots containing soil to which basal nutrients had been added and the pH adjusted to 6.5. Hartog yielded 2.4 g of grain per plant when grown at 280 µL CO2 L-1. This yield was increased by 38% and 75% at CO2 concentrations of 350 µL L-1 and 900 µL L-1 respectively. These changes were due to increases in both grain number and individual grain weight as the level of CO2 was raised. The yield of Rosella was unaffected by altering the CO2 concentration. Increasing the CO2 concentration reduced grain protein concentration of cv. Hartog from 17.4% at 280 µL CO2 L-1 to 16.5% and 16% at CO2 concentrations of 350 µL L-1 and 900 µL L-1 respectively. The grain protein concentration of cv. Rosella was reduced from 10.7% to 10.2% by increasing the CO2 concentration from 280 µL L-1 to 350 µL L-1; however, an additional increase in the CO2 concentration to 900 µL L-1 had no effect on grain protein concentration. In Hartog flour, the highest proportion of polymeric protein in the flour (7.7%) occurred at 280 µL CO2 L-1. This was reduced to 6.3% at 350 µL CO2 L-1 but then increased again to 7.0% at 900 µL CO2 L-1. These changes in concentration of polymeric protein were correlated (r2=0.58) with changes in mixing properties. The mixing time required to produce optimum dough strength was greatest at 900 µL CO2 L-1 (181 s), then 141 s and 151 s at 350 µL CO2 L-1 and 280 µL CO2 L-1 respectively. These changes in mixing time could not be explained by changes in grain protein concentration. The proportion of ‘B’ starch granules (<10 m diameter) increased from 25% of total weight of starch at 280 L CO2 L-1 to 30% at CO2 concentrations 350 and 900 µL L-1. There were generally no effects of CO2 concentration on dough mixing properties or starch granule size distribution for Rosella.

High Power Laser Applications in Steel Industries

The full-scale use of lasers in the steel industry began nearly 23 years ago with their applications as controllable light sources. Its contribution to the increase in efficiency and quality of the steel making process has been important and brought us the saving of the energy, the resource and the labor. Laser applications in the steel making process generally require high input energy, so it is essential to consider the interaction between the laser beam and the irradiated material. We have developed plenty of new high-power-laser applications for the steel making process with their considerations in mind. A review of the following high-power-laser applications is given in the present paper: (1) Wedge shape welding with multiple reflecting effectof CO2 laser beam, (2) Butt welding of extra thin steel sheets by ripple mode Nd-YAG laser, (3) Developed laser flying welder connect hot bars of around 1100 °C for continuous hot rolling mill using two 45 kW CO2 lasers.

Biodiversity and CO2: Global Change is Under Way

In this article our current understanding of CO2 effects on complex vegetation is outlined and first results of the CO2 enrichment experiments conducted as part of the Biodiversity Module of the Swiss Priority Programme Environment are discussed. It is known for two centuries that plants need CO2 for photosynthesis. Elevated concentrations of CO2 were found to stimulate growth, and thus CO2 fertilization became a standard tool in greenhouse horticulture. Meanwhile it became clear that this stimulating effect of CO2 on plant growth depends on the availability of other resources like water, nitrogen and phosphate, which are usually very abundant in agro-systems but limited in natural ecosystems. However, even when resources are short some plants (the “winners”) may become more efficient competitors for these resources than others (the “losers”), causing global CO2 enrichment to become a biodiversity issue. While 1 per cent of the global biomass is growing under fertile agricultural conditions, more than 95 per cent of the global vegetation produces biomass without any artificial addition of resources. Hence, understanding CO2 effects on biodiversity requires experiments conducted in diverse, low-fertility systems, a model for which are calcareous grasslands. First results indicate increased carbon uptake by plants during the day but no change in biomass. In addition, tissue quality changes and species-specific responses were observed which were not predicted by any current theory. These results indicate that predictions of the future development of complex plant assemblages can not be made from data obtained in simplified fertile systems but need to consider the multitude of interactions between organisms as they occur in the field. With more than 70 plant species per 100 m2 this precious grassland system can serve as a model for other highly diverse natural ecosystems.

Growth studies on the lactic streptococci. II. The effect of agitation on the growth characteristics of Streptococcus lactis ML 8 in batch culture.

SummaryInvestigations on the growth characteristics ofStreptococcus lactisML8in skim-milk medium have indicated that agitation of the medium may decrease the growth rate of the organism by decreasing the availability of CO2(CO2effect) and of soluble nitrogen (soluble nitrogen effect). The former effect was observed only when the CO2concentration was depleted by heat sterilization; the latter occurred when a certain threshold level of agitation was exceeded. Results suggested that the soluble nitrogen affect was caused by an alteration in the rate of diffusion of substances formed in the immediate vicinity of the bacterial cell by the proteolytic enzyme system.