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Taking the Yangtze River Delta (YRD) of China as the research area, this paper studies the influence of freight structure adjustment and energy intensity on carbon dioxide (CO2) emission from the transportation industry. Sample data from 1990 to 2019 are selected, and co-integration analysis is performed using three independent variables: energy intensity, turnover ratio of railway to highway (R/H), and turnover ratio of railway to waterway (R/W). Then, an autoregressive distribution lag-error correction model (ARDL-ECM) is established to estimate the long-run and short-run relationships among the variables through unit root test, autoregressive distributed lag (ARDL) boundary test, and Granger test. The results show that in the long run, the growth of energy intensity leads to the long-term growth of CO2 emission in the transportation sector of the YRD, and R/W and R/H have a suppressive effect on CO2 emission. Granger causality indicates that there is a bidirectional causal relationship between energy intensity and CO2 emission. This work can be a reference for government departments to formulate policies related to carbon emissions in the transportation industry. [ABSTRACT FROM AUTHOR]

Energy generation and pollutant emissions are two faces of the same coin, as the current energy sources i.e., fossil energy, are still considered to be major sources of greenhouse gases (GHG). Therefore, shifting to cleaner energy sources imposes itself as an inevitable solution to reduce this environmental cost. In this paper, a hybrid system based on the multi-agent approach and Long Short-Term Memory (LSTM) neural networks to forecast the energy production and its carbon dioxide (CO2) emissions and simulate the potential emission reduction in case of switching to renewable energy sources is presented. The proposed system's architecture consists of combining LSTM models with the agent-based technology, where multiple LSTM forecasting models were trained to forecast the production of each type of the studied energies and then estimate the equivalent emitted CO2 and calculate the influence of the renewable energy inputs on the carbon emissions and the fossil fuels consumption. The simulation process consists of two phases: firstly, each forecasting agent uses a specific LSTM model to forecast short-term energy production. Secondly, these agents send the forecasted values to the coordination agent who is responsible for calculating the total CO2 emissions and the benefits of the renewable energy inputs. [ABSTRACT FROM AUTHOR]

Reducing greenhouse gas emissions or collecting and converting existing greenhouse gases has become a global concern. One of the most effective methods of utilizing CH4 and CO2 resources is the dry reforming of methane (DRM). Transition metal carbide catalysts have attracted wide attention because of their excellent catalysis performance and carbon deposition resistance. However, pure-phase carbides are easily oxidized and deactivated at atmospheric pressure in DRM reactions. There is a problem of poor dispersion (Mo2C 17 m² /g). Therefore, this paper summarizes the effects of adding active sites and supported carbides on the DRM reaction, discusses the role of active sites and supports in the catalyst, and introduces the different preparation methods of transition metal carbides. This paper also reviews the catalyst mechanism of transition metal carbides in DRM reactions. Nevertheless, the current research in this field needs to be deepened. Therefore, it is necessary to strengthen the exploration of various catalyst preparation methods and mechanisms, so as to realize future improvement in this field. [ABSTRACT FROM AUTHOR]

Sweep efficiency of stagnant and poorly drained reservoir zones is extremely relevant task during gas and chemical flooding of hard-to-recover reserves. The paper presents the results of the field implementation of the in-situ CO2 generation technology to recovery of residual oil reserves and increase the sweep efficiency factor. The article presents the results of theoretical and laboratory studies, as well as field cases of an energy- and resource-saving method for oil recovery increase and improving oil production. The results of the reservoir stimulation confirmed the increase in the total incremental oil production after treatment operation on recovering residual oil reserves on. [ABSTRACT FROM AUTHOR]

As the industrial revolution progresses, carbon dioxide (CO2) and sulfur dioxide (SO2) are major concerns because they are the main contributors to greenhouse gases. The concentration of these harmful gases in the industry is very high, which is emitted by workers and industrial materials. Therefore, it is required to maintain a safe percentage of CO2, SO2, and other harmful gases in the air of industry and ensure safety from fire accidents. This paper presents a compressor driven system that could capture harmful gases including CO2 and SO2 from the polluted air of different industries and households. The captured and separated CO2 works as a fire extinguishing agent to safeguard fire accidents for large industries and households. Thus, this system ensures a protected working place and a healthy atmosphere for industrial workers. Besides, this system can be applied in place of the exhaust gas recirculation (EGR) system in small industries and for a four-wheeler, internal combustion engine, as this system could capture and separate the harmful carbon dioxide and sulfur dioxide. This paper also presents a developed model of different polymeric membranes to simulate the separation of carbon dioxide after the post-combustion process. Computational Fluid Dynamics (CFD) has been performed by COMSOL 5.5 to observe the carbon dioxide separation by polymeric membranes like polycarbonate (0.07 mol/m3) and polytetrafluoroethylene (0.1 mol/m3) polymeric membranes for specific pore sizes which is comparable to experimental data (0.05 mol/m3). [ABSTRACT FROM AUTHOR]

The CO2-containing natural gas is increasing, and there is an urgent need for green treatment of natural gas containing CO2 to realize the utilization of natural gas. Conventional natural gas decarbonization methods have drawbacks such as non-environmental friendliness, and the low-temperature condensation separation of carbon dioxide (snowing-separation) method as a green method of carbon capture is proposed in this paper. Aiming at the characteristics of CO2 condensation in the snowing-separation process, the growth process of CO2 crystals is obtained by simulation using the CA (Cellular Automata) method and finds that the effect of supersaturation on the growth of CO2 crystals is exponential. The snowing-separation process at .5 MPa is analyzed, and it is found that the condensation range is 158.51 K–173.86 K, the upper limit of CO2 mole fraction in natural gas is 10.1%, and the minimum separation time is 8.65 × 10−8s. Analyzing the influencing factors of CO2 separation efficiency, combining the simulation results with the experimental results, the maximum relative error is 13.93%, which can better predict the snowingseparation technology of CO2 in natural gas, and then promote the development of efficient low-temperature carbon capture process. [ABSTRACT FROM AUTHOR]

As the world No.1 emitter of carbon dioxide (CO2), China has made up its mind to act on climate change. After trials in six pilot regions- Shenzhen, Shanghai, Beijing, Guangdong, Tianjin, Hubei, and Chongqing- a nationwide ETS has been established and implemented in line with the Thirteenth Five-Year Plan period (2016–2020). This paper simulates the effect of a national ETS in China using GTAP 9.1 database and a revised GTAP-E model. The simulation results show that the ETS is very effective in emissions reduction but will cause a mild economic contraction. At the sectoral level, the energy and resource sectors and energy intensive sectors are to be hit hard while most other sectors are affected negatively but insignificantly. [ABSTRACT FROM AUTHOR]

The paper reviewed the current perspectives on the development of carbon dioxide (CO2) sequestration through its process conversion into calcite. The process occurs in either geological or biological systems. However, geological sequestration is an expensive process, which is slow in comparison to bio-sequestration. Recently, the bio-sequestration of atmospheric CO2 into the soil using microorganisms such as algae has been investigated. However, the algae cannot be used in the bio-concrete due to their nature as phototrophic organisms. In contrast, bacteria are the most potent organisms in bio-concrete technology. The use of bacterial species in the bio-aerated concrete bricks (B-ACB) and its potential to bio-sequestrate CO2 represents a future strategy to reduce high CO2 pollution. Bacterial cells can capture CO2 by accelerating the carbonation processes, which convert CO2 into calcium carbonate (CaCO3) via carbon anhydrase and urease enzymes. The present paper aimed to highlight and discuss the applicability of bacteria in the B-ACB for capturing and storing CO2. It is evident from the literature that the new trends to use bio-concrete might contribute to the reduction of CO2 by accelerating the carbonation process and strengthening the B-ACB. [ABSTRACT FROM AUTHOR]

In the face of mounting global climatic pressures, negative emission technologies (NETs) for carbon dioxide removal (CDR) are increasingly proposed as necessary for meeting climate targets. While initial work has identified the potential of terrestrial NETs, a diverse set of marine/ocean-based NETs are gaining new and particular attention. Emerging studies on the feasibility of marine NETs are urgently needed, especially to explore the logics that public groups use to judge different approaches, and to ensure that design and governance of these technologies align with public values and priorities. This study explores factors of interest in understanding public views on four marine NETs, both perceptions of climate severity and urgency, and beliefs about marine environments. It uses a quantitative survey to explore how a representative sample of people in British Columbia, Canada and Washington state, United States evaluate four marine NETs: coastal restoration; ocean alkalinity enhancement; ocean fertilization; and offshore direct air carbon capture and storage. We find that perceived severity and urgency of climate change predicts greater comfort with all NETs studied, and views of marine environments as adaptable, fragile and manageable vary in predicting both greater and lesser comfort. Drawing upon these insights, the paper offers reflections on the conditional thinking linked with emerging views of marine NETs, concluding with methodological suggestions for future research on public perceptions as concerns the deployment of ocean-based CDR near and long term. Incorporating these insights into policy for ocean-based CDR will be important to ensuring responsible governance of these technologies. Key policy insights Incorporating research on public perceptions will be important to the design of marine NETs and accompanying policies. Public groups in both British Columbia and Washington expressed high levels of comfort with coastal restoration, some comfort with offshore direct air carbon capture and storage, and some discomfort with ocean alkalinity enhancement and ocean fertilization. Perceived severity and urgency of climate change predicted greater comfort with all approaches; this evidence aligns with a small but growing body of scholarship indicating openness to environmental intervention amongst public groups concerned with climate impacts. Beliefs about marine environments, namely whether they are 'adaptable', 'manageable' or 'fragile', also predicted comfort, suggesting that CDR in ocean contexts requires further examination regarding public perceptions. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide fracturing can effectively relieve the environmental pressure caused by in-situ production of oil shale. In order to study the process of fracture propagation during supercritical carbon dioxide fracturing, a fracture propagation model of supercritical carbon dioxide fracturing is established in this paper, and an unsteady temperature field model is introduced. Based on the discrete fracture model, the fluid temperature field in one-dimensional fracture is coupled with the temperature field of two-dimensional reservoir rock. The new model also takes into account the real-time variation of carbon dioxide physical parameters, which are calculated by Span-Wagner and Vesovic equations. Based on this model, the influencing factors of fracture propagation in supercritical carbon dioxide fracturing are analyzed. The results show that the leak-off coefficient has an obvious effect on fracture propagation, so an additive needs to be developed to reduce the leak-off. Since carbon dioxide is a compressible fluid, the reservoir temperature and the original in-situ stress also have a significant impact on the fracture propagation. The temperature of carbon dioxide at the bottom of the well has no significant effect on fracture propagation, because carbon dioxide will quickly reach reservoir temperature when it enters the formation. Comprehensive considering the fracture length, width, filtration, and potential effect on proppant transport during supercritical carbon dioxide fracturing, the injection rate should be as high as possible. [ABSTRACT FROM AUTHOR]

The experiments on microwave pyrolysis of soybean straw are studied to produce hydrogen-rich gas under CO2 atmosphere in this paper. The microwave power has an important effect on the temperature. The final temperature increases and the time to obtain the highest temperature is shortened with the power increasing. The gas yield, H2 yield and potential H2 yield increase rapidly with the power increasing, and the gaseous yield at CO2 atmosphere is up to 55.70% at 1000 W, and it is higher than N2 atmosphere. The main components of microwave pyrolysis gas product are H2 and CO, the content of syngas (H2+ CO) at CO2 atmosphere is 84.19% at 1000 W, which is more than N2 atmosphere. However, H2/CO ratio is about 0.80 at CO2 atmosphere, which is lower than N2 atmosphere, and H2/CO ratio at CO2 atmosphere is not suitable for the requirements of chemical synthesis. If it is used to synthesize liquid fuels, H2/CO ratio must be adjusted. [ABSTRACT FROM AUTHOR]

Lime is a product derived from the thermal decomposition of limestone (mainly calcium carbonate, CaCO3) into quicklime (CaO) and carbon dioxide (CO2), also called calcination. Controlled reaction with water is used to manufacture hydrated lime (Ca(OH)2) products. Lime is used in a wide variety of applications: metals industry, construction materials sector, civil engineering, environmental protection, agriculture, and chemical industry. Lime production is one of the sources of anthropogenic CO2 emissions resulting in global warming and ocean acidification. However, a proportion of the CO2 emitted during the calcination is reabsorbed by the lime during the product life within its different applications. This process called carbonation is thermodynamically favoured because it is exothermal. It allows permanent CO2 storage in a stable product since the lime combines with gaseous CO2 reforming CaCO3. This paper reports a comprehensive literature review on the carbonation potential of lime in different applications. The total carbonation potential is assessed as carbonation rate, i.e. the ratio between the CO2 reabsorbed through carbonation during the operational life of lime and the CO2 emitted during limestone calcination. This study provided preliminary evidence that, based on the current EU market, on average 23–33% of lime process emissions are carbonated during the use phase. Carbonation over time is also analysed for the lime applications where information is available. For three applications, namely water, flue gas cleaning and pulp and paper, the carbonation reaction is instantaneous. Up to 22% of the calcination emissions are absorbed within five years based on the current EU market. [ABSTRACT FROM AUTHOR]

Satellites provide global long-time series of spatio-temporal continuous CO2 observations. However, it is difficult to be applied to the study of small-scale carbon cycle because of its low spatial resolution. In this paper, the Greenhouse Gases Observing SATellite (GOSAT) XCO2 data are super-resolution reconstructed using bicubic interpolation, which improved the spatial resolution from 2.5o to 0.5o. CO2 measurements from ten selected TCCON sites are used to compare with the reconstructed GOSAT. Further, the high accuracy Orbiting Carbon Observatory-2 (OCO-2) data analysed by the combination of geographical grid statistics and kriging is used to evaluate the reconstructed data. The results show that compared with the original GOSAT data, the reconstructed GOSAT data not only improves the spatial resolution but also has little loss of the average accuracy. The mean error of original data has significant seasonal fluctuations with a peak from February to March and a trough from June to July [ABSTRACT FROM AUTHOR]

This paper discusses the Clean Power Plan (CPP) legislation and its repeal on the emissions from electricity generation sources. Demand side management (DSM) is probed to illustrate an alternative technique to achieve lower emissions goals. This work discusses the Climate Action Plan (CAP) corresponding to Fort Collins, Colorado, U.S. and its timeline targets. Therefore, the paper provides a technique for prioritizing DSM options through a Multi-Criteria Decision-Making (MCDM). In that regard, a framework is created to examine several options of DSM in reducing carbon footprints. The algorithm states that affecting Greenhouse Gases (GHG) in electric power system is the main goal and this can be achieved by implementing DSM technologies in distribution systems. MCDM algorithms have been proposed to prioritize alternatives and select the ones that achieve suitable emissions reduction. The findings from Analytic Hierarchy Process (AHP) show that the “communication and intelligence” option has a global priority of 0.341 making it the potential optimal alternative in achieving the goal. The second alternative is “electric stationary storage” with global priority of 0.207. The results obtained from Analytic Network Process (ANP) suggest that “communication and intelligence” is the optimum technology to reach the target with a priority of 0.284. [ABSTRACT FROM AUTHOR]

The reduction of CO2 into clean energy through electro catalytic technology provides a promising solution to alleviate energy shortages. In this paper, the graphitised material-supported metal dimer used for electro catalytic reduction of CO2 was proposed, and the reduction reaction mechanism was explored by density functional theory. The results indicate that the hydrogenation reduction of CO2 tends to occur preferentially, and it was found that improving the stability of catalyst structure can reduce the free energy of reaction and improve the adsorption effect of reactants, which significantly increase the conversion efficiency of CO2. The activation of CO2 on the catalyst surface is closely related to the binding of O atoms on the metal sites, the main reduction products and their reaction pathways were clarified. The reduction over potentials of CuCo-C, CuRh-C, CuZn-C and ZnCu-C were 0.915, 0.820, 0.774, and 0.354 V, respectively, thus ZnCu-C had a lower reduction over potential and higher catalytic efficiency. [ABSTRACT FROM AUTHOR]

This paper addresses the impact of political regimes on carbon emissions (CO2) from a historical perspective, covering the period of 1970–2015. Our sample consists of 153 countries that we follow for 20 years before the transition (1970–1990) and 26 years after it (1990–2015). During transition, post-Communist states experienced a decline in CO2, when controlling for economic variables. Transition had a positive impact on the environment only in cases when it was associated with democratization. When transition has led to consolidation of autocratic regimes, CO2 has increased. [ABSTRACT FROM AUTHOR]

This paper introduces the Fleet Size and Mix Vehicle Routing Problem with Synchronized Visits (FSM-VRPS), an extension of the Vehicle Routing Problem with Synchronization (VRPS), where a mixed fleet composed of electric and conventional bikes, and passenger cars having different acquisition costs are considered. The problem consists of planning a set of different vehicle routes to serve a set of clients who may require more than one visit by different healthcare specialists, and some of these visits should be synchronized. Moreover, each client must be visited within a specified time window. In addition, the problem uses bikes to reduce Carbon Dioxide (CO2) emission for environmentally cleaner routing operations. This problem has many real-life applications, such as the scheduling of visits for homecare givers in the healthcare sector. We present a mixed integer linear-programming formulation and develop a Multi-Start Adaptive Large Neighborhood Search with Threshold Accepting algorithm. The results showed that our algorithm is highly effective on the FSM-VRPS, as well as on the heterogeneous VRPS. We also demonstrate the advantage of adopting different types of vehicles in terms of reducing the number of vehicles and costs. The analysis of the results also indicated that the new components added to the standard Adaptive Large Neighborhood Search algorithm enhanced intensification and diversification mechanisms during the search process. [ABSTRACT FROM AUTHOR]

Ventilation plays an important role in mitigating the risk of airborne virus transmission in university classrooms. During the early phase of the COVID-19 pandemic, methods to assess classrooms for ventilation adequacy were needed. The aim of this paper was to compare the adequacy of classroom ventilation determined through an easily accessible, simple, quantitative measure of air changes per hour (ACH) to that determined through qualitative "expert judgment" and recommendations from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and the American Conference of Governmental Industrial Hygienists (ACGIH)®. Two experts, ventilation engineers from facilities maintenance, qualitatively ranked buildings with classrooms on campus with regard to having "acceptable classroom ventilation." Twelve lecture classrooms were selected for further testing, including a mix of perceived adequate/inadequate ventilation. Total air change per hour (ACH) was measured to quantitatively assess ventilation through the decay of carbon dioxide in the front and rear of these classrooms. The outdoor ACH was calculated by multiplying the total ACH by the outdoor air fraction. The classrooms in a building designed to the highest ASHRAE standards (62.1 2004) did not meet ACGIH COVID-19 recommendations. Four of the classrooms met the ASHRAE criteria. However, a classroom that was anticipated to fail based on expert knowledge met the ASHRAE and ACGIH criteria. Only two classrooms passed stringent ACGIH recommendations (outdoor ACH > 6). None of the classrooms that passed ACGIH criteria were originally expected to pass. There was no significant difference in ACH measured in the front and back of classrooms, suggesting that all classrooms were well mixed with no dead zones. From these results, schools should assess classroom ventilation considering a combination of classroom design criteria, expert knowledge, and ACH measurements. [ABSTRACT FROM AUTHOR]

With the rapid development of regional economy, energy consumption and carbon dioxide emission increase sharply. This study examines the relationship between carbon dioxide emissions and regional economic growth. Based on the mean value decomposition method of double logarithm, the model was built to identify the key indexes affecting the decomposition, and the carbon emission formula was calculated to obtain the regional carbon dioxide emission. Based on the actual data, the kuznets curve model is established to represent the relationship between CO2 emission and regional economic growth in logarithm form. The unit root test, co-integration test and granger causality test are carried out for the correlation sequences in the kuznets curve model in order to realize the research on the relationship between CO2 emission and regional economic growth. This paper discusses the relationship between carbon dioxide emission and regional economic growth through an example. It shows that the relationship between carbon dioxide emission and regional economic growth is inversely u-shaped, and there is a kuznets curve between the two. According to the result of empirical analysis, the paper puts forward some suggestions to reduce energy consumption and improve energy efficiency, which is helpful to improve social and economic structure and promote social and economic development. [ABSTRACT FROM AUTHOR]

Rotary drying is one of the most common unit operations in industries. It is a complex nonlinear process, and it is difficult to control with conventional methods. In this paper, a fuzzy multivariable controller is designed for an industrial rotary drying system. This fuzzy controller is applied to a fertilizer production unit to save energy and improve its performance. Based on the dryer operating conditions, the proposed control system aims to keep the exhaust gas temperature at the dryer outlet as close as possible to the optimum value. Thus, a reduction in energy consumption is achieved without losing the quality of the final product. Practical aspects of the industrial reality, such as the plant lacking an online moisture measurement instrument, are considered. The results prove that the proposed fuzzy control is able to reduce biomass consumption by 9%, which represents an annual reduction of 648 tons of carbon dioxide (CO2) emissions to the atmosphere. [ABSTRACT FROM AUTHOR]

In recent years, China's air quality problem is very serious. Among them, carbon dioxide emissions have been high, which has caused a series of ecological and environmental problems. In order to deeply study the relevant problems, this paper selects the information priority damping gray model to study and predict the carbon emissions of thirty-one provinces and municipalities in China. The model can give priority to new information and adjust the prediction trend, the accuracy of the model is verified by several cases. Through the data collection and data analysis of relevant provinces and cities, it is concluded that a total of twenty-one provinces and municipalities can reach the carbon peak in 2030, of which the carbon dioxide emission of Beijing is expected to drop to 51.3774 million tons by 2030. Ten provinces will not be able to reach the carbon peak by 2030. Among them, by 2030 the carbon dioxide emission of Jiangsu Province is expected to increase to 84.4668 million tons, but the growth rate is declining. The research results can be used as a reference for relevant departments. [ABSTRACT FROM AUTHOR]

For a smart grid system operating with clustered generating units, the challenge usually lies in the optimal scheduling of energy resources. Thus, the improvement of a unit commitment problem gains importance in the present power network. In this paper, a novel probability algorithm is proposed for solving the unit commitment problem, in which five separate units from a four-cluster group are operated for one day. This is done with the aim of optimizing the characteristics such as optional units, generation, operating, and marginal cost. Being a multi-objective function, the other factors such as cost response, unit commitment of supply clustering units, clustering of combined operational units, and CO2 emissions are also included. For this study, an RLC load is mathematically modeled in the cluster system, whereas the Unit Control is provided by a Converter and Battery Management Unit. The clustering model developed along with the Unit demand aims to increase the optional units (from 20 to 100 units), decrease the average demand (from 99 to 93 percentage), and lower the generating and marginal costs (from Rs.23,881 to Rs.21,079, Rs.43,082 to Rs.42,111, Rs.71,162 to Rs.64,955, Rs.83,169 to Rs.81,694, Rs.104,104 to Rs.102,928). The suggested algorithm is simulated for a comprehensive smart grid system and the response for marginal cost, CO2 emissions are obtained. In comparison to conventional schemes, the results of the proposed optimization approach show a reduction in the Carbon dioxide emission (in the range of 100 to 400 kg) and in the losses after adding working units with cluster spans of 0.5 to 1.5 kW. [ABSTRACT FROM AUTHOR]

Exposure to air can cause amine solutions in CANada Deuterium Uranium (CANDU) reactor secondary coolant circuit feed tanks to absorb carbon dioxide (CO2). Likewise, carbon dioxide can be absorbed directly into the amine-containing secondary coolant by air ingress during shutdown, lay-up, and startup. Sampling operations, including transferring the sample to the laboratory and subsequent analyses, can also provide opportunities for CO2 contamination. This paper reports the results of laboratory and chemical modeling studies to examine the effects of CO2 contamination on aqueous morpholine solutions. The chemistry of CO2 uptake by feed tanks containing up to 50 wt% (11.5 mol·kg-1) morpholine at 25°C was modeled using the OLI Studio 9.5.2 chemical equilibrium model, and the speciation was confirmed by 13C nuclear magnetic resonance spectroscopy (NMR) measurements. The effects of CO2 contamination on the pH of the secondary coolant containing 60 ppm (0.006 wt%, 7.00 × 10-4 mol·kg-1) morpholine and the resulting effects on the solubility of magnetite and nickel oxide from 25°C and 250°C at steam saturation were modeled as a function of CO2 loading using the Electrical Power Research Institute chemical modeling software MULTEQ v.8. The chemical modeling calculations show that concentrated alkaline morpholine solutions at room temperature and pressure would be expected to have a strong tendency to absorb CO2 and have additional uptake abilities due to the formation of morpholine carbamates. For dilute morpholine solutions at room temperature and pressure, the solutions are still sufficiently alkaline to absorb enough CO2 to cause a measurable change in the pH of the secondary coolant. This effect was shown to be negligible under reactor operating conditions. The absorption of CO2 would potentially have the most effect on either unprotected feed tanks or during lay-up conditions in the steam generators, as it could depress the pH of the lay-up solution and adversely affect the rate of corrosion in the internal components of the steam generators (e.g., carbon steel materials). The 13C NMR measurements on samples of 50 wt% aqueous morpholine solutions from feed tanks at the Ontario Power Generation's Pickering Nuclear Generating Station found that CO2 was below the 0.02 wt% detection limit, and suggest that the procedures used to avoid CO2 contamination in feed tanks are effective. The 13C NMR was shown to be an effective tool for monitoring CO2 uptake by morpholine solution in the feed tanks under conditions in which they may have undergone abnormal exposure to air. [ABSTRACT FROM AUTHOR]

To reach the short-term targets of the carbon dioxide limit, measures such as carbon capture and storage are necessary. The objective of this paper is to assess some low-temperature post-combustion technologies for the capture of CO2 from combustion gases. Two methods for the liquefaction and separation of CO2 are discussed: The use of the low-temperature exergy of liquefied natural gas (LNG), while regasifying the LNG, and a refrigeration cycle with helium as the working fluid. Each of these methods is evaluated at three CO2 concentrations: 30%, 13%, and 4%. The results showed that an increase in the concentration of CO2 in the combustion gases causes a large increase in the overall exergetic efficiency and a large decrease in the cost of CO2 capture and energy penalty of the capture process. In addition, these advantages can be seen when the liquefaction method is changed from helium refrigeration cycle to LNG regasification. For a 30% CO2 concentration using LNG, the overall exergetic efficiency is 41.2%, and the cost of CO2 capture is 45.5 $/tCO2 with a CO2 capture rate of 96.3%. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model has been formulated by considering carbon dioxide in the atmosphere, human population, forest biomass and global warming as separate compartments. It is assumed that human and forest biomasses grow logistically. It is assumed that the growth rate of human population is affected by global warming through different natural and human activities. Also, it is considered that global warming of the environment increases gradually due to the increase of carbon dioxide in the atmosphere as well as deforestation. Different equilibrium points have been determined. Also, the stability of our proposed system has been explored around these equilibrium points. Hopf bifurcation analysis have been done with respect to some important parameters of our proposed model. Finally, some numerical simulation results have been presented to verify our theoretical results. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive list of Carbon Capture and Utilization technologies and applications, ranging from lab-scale R&D activities reported in academic papers to commercially established uses of carbon dioxide. Carbon dioxide, as a source of carbon, has the potential to be used as a solvent, as a raw material in the manufacturing of fuels, carbonates, polymers, and chemicals, or as a recovery agent in techniques such as enhanced oil recovery or enhanced coal bed methane. In this paper, a literature review and recent advances of each technology are explained. To finish, most relevant Life Cycle Assessment studies carried out by experts in this field are included. Among the different alternatives studied for the use of carbon dioxide, the processes of carboxylation, consisting the synthesis of carbonates and carboxylates, have stood out. Both the production of salicylic acid as well as that of dimethyl carbonate and mineral carbonation are presented as the most likely applications of carbon dioxide, at least, in the short term. [ABSTRACT FROM AUTHOR]

Recent advancement in enhanced oil recovery techniques has given petroleum industries the chance to find optimum solutions to recover remained oil from hydrocarbon reservoirs. This paper aims to experimentally investigate the profound impact of reservoir characteristics such as permeability and pressure drop and foams properties such as foam quality and foams resistance factor in enhanced oil recovery processes. Therefore, a hybrid recovery technique containing a thermal recovery method (carbon dioxide) and a chemical method (foam injection) with different brine concentrations was performed to enhance the oil recovery factor. Consequently, after brine injectivity, foam injection has provided the highest recovery factor among other scenarios in shale reservoirs. Permeability increase has caused to increase in the resistance factor as the fluid mobilization is increased in the porous media. Therefore, for 80% of foam quality, the resistance factor is about 7.5, while for 40%, foam quality is about 5 at the permeability of 10mD. [ABSTRACT FROM AUTHOR]

In 2019, New York State passed aggressive new climate legislation to reduce greenhouse gas (GHG) emissions and laid out major changes for how emissions are reported. One change is the inclusion of emissions from outside of the boundaries of the State if they are associated with energy use within NY; the traditional inventory considered emissions only within the State. The new legislation also mandated that methane emissions be compared with carbon dioxide over a 20-year time frame rather than the 100-year time frame previously used by NY and still used by virtually all other governments globally. This reflected the desire of NY's policymakers for a tool that evaluates emissions from the standpoint of energy consumption and that more heavily weighs the role of methane as an agent of warming over the next few decades. This paper compares emissions based on the new approach for GHG reporting with the traditional inventory. The traditional inventory is driven almost entirely by carbon dioxide emissions. As of 2015, these carbon dioxide emissions had declined by 15% since 1990 due to an 88% decrease in coal consumption and a 27% decrease in consumption of petroleum products, although consumption of natural gas had increased by 57%. Methane emissions increased by almost 30% between 1990 and 2015, largely due to the increased consumption of natural gas. According to the new GHG reporting rules, methane contributed 28% of all fossil-fuel emissions in 1990 and 37% in 2015. Total GHG emissions remained virtually unchanged from 1990 to 2015. [ABSTRACT FROM AUTHOR]

RP-3 kerosene fuel is the dominant hydrocarbon fuel used in civilian airplanes in China. Lately, many administration and universal organizations imposed a stringent standard for civilian airplanes pollutants emission. The amount of pollutants emission can be affected by the introduction of a variety of additives into flames, such as inert diluents, gaseous additives. This paper reports the effects of different inert gases (nitrogen and helium) and carbon dioxide dilutions in the oxidizer side on soot characteristics generated from RP-3 kerosene inverse diffusion flames. Flame diluted by carbon dioxide produced less amount of soot compared to flames diluted by nitrogen and helium, possibly because of changes in flame shape and properties such as flame diameter and availability of oxygen atoms. Carbon dioxide suppressed soot precursors formation in inception zone and released particles with smaller diameter due to lack of hydrogen radicals, an increase of hydroxyl radicals pool concentration, and decrease in flame temperature. Flame diluted by helium generated much soot aggregates with bigger primary particles diameter compared to base flame (flame diluted by nitrogen) as a result of high temperature. Soot particles produced in carbon dioxide diluted flame had more amorphous nanostructure, longer interlayer spacing and nanocrystallite height, shorter nanocrystallite width, lesser number of layers, and higher oxygen content compared to flame diluted by nitrogen and helium, which reflected a better oxidation reactivity among other diluted flames. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical study of CO2-based transcritical Rankine cycle (CTRC) for engine's waste heat recovery, involving comparison and selection of four CTRC configurations for two engine types, namely a gasoline engine and a diesel engine. The results of configuration comparison show that the CTRC configuration with both a preheater and a regenerator may be more suitable for both two type engines with water-cooling system. If only recovering the waste heat of exhaust gas, the regenerated CTRC configuration may be more appropriate. The results of engine type comparison show that engine load has slighter effect on the CTRC performance for the gasoline engine compared with that for the diesel engine. Particularly, this paper jointly considers the effect of CTRC weight to evaluate the final CTRC output, which is significant for the vehicle engine. A critical weight is found for the two engines based on 100% engine load, 215 kg for the gasoline engine and 998 kg for the diesel engine, which is the upper limitation of the CTRC weight design. When considering the weight effect, the diesel engine may be the more suitable recovery target compared with the gasoline engine, owing to the more stable reaction of output performance to the CTRC weight. [ABSTRACT FROM AUTHOR]

This introduction takes a critical look at the heterogeneous corpus of social science research on climate change and Christian religion. The central concern is to present analytical alternatives to the universalist-essentialising approaches which, on the basis of a supposedly inherent contradiction between science and religion, exclude or devalue Christian contestation and modification of climate change discourse. With reference to the empirical-analytical richness of the contributions on Fiji, Vanuatu and Kiribati, this paper highlights the multiplicity, contrariness and processuality of the religious-political practice of Pacific Islanders in response to climate change as both a scientific narrative and a physical reality. The range of topics of the introduction includes the religious dimensions of blame, transnational networks of Christian actors and institutions as well as Christian framings of the nexus of climate change, mobility and resettlement. In addition, it outlines possible fields of future research such as the media politics of Christian institutions' representations of climate change and a historical re-examination of missionary work in Oceania from the perspective of the entanglements of carbon and Christianity. [ABSTRACT FROM AUTHOR]

Competitive adsorption of CO2/N2/CH4 on coals is important to evaluate potential application of CO2- or N2 – ECBM, which is not fully addressed in previous studies. In this paper, CH4, CO2, and N2 adsorption behaviors are experimentally compared at different reservoir temperatures (307 K, 318 K, and 333 K) and pressure up to 9 MPa. It is found that adsorption capacities all decrease with increasing temperature for CH4, CO2, and N2, while the differences in maximum adsorption capacity at different temperatures is not significant. Maximum adsorption capacity of anthracite coal is much larger than those of bituminous coals, while the maximum adsorption capacities of two selected bituminous coal are close to each other. The maximum adsorption capacity of CO2 is 1.93 mmol/g，which is significantly higher than that of CH4 and N2 with exactly 1.80 mmol/g and 1.11 mmol/g respectively. However, for a given coal sample, gas type does not affect the thermal-stimulated desorption capacities significantly. [ABSTRACT FROM AUTHOR]

Ionic liquids have a great potential in capture and separation of carbon dioxide (CO2), and the solubility of CO2 in ionic liquids is one of key data for engineering applications. In this paper, the critical properties of ionic liquids are combined with deep learning models (CP-DNN, CP-CNN, CP-RNN) to establish theoretical prediction models of CO2 solubility in ionic liquids. The predictive performance of these framworks is able to meet or exceed the predicted effects of the method based on thermodynamic models (PR,SRK) and machine learning method (XGBoost). For CP-RNN, the coefficient of determination (R2) between experimental and predicted values is 0.988, CP-CNN is 0.999, and CP-DNN is 0.984. This research can avoid complex computational characterisation, it is to provide a theoretical method to further enrich and improve the data information analysis of the solubility of CO2 in ionic liquids. [ABSTRACT FROM AUTHOR]

In this paper, the gas composition and isotopic characteristics of the tight sandstone of the Upper Triassic Xujiahe Formation in the western Sichuan depression were analyzed, and the origin of hydrocarbon gas, rare gas and CO2 in natural gas were determined. The hydrocarbon gas content in the tight sandstone gas of the Xujiahe Formation is the highest, ranging from 96.43% to 99.44 vol.%, while the non-hydrocarbon gas content is only 0.34–2.73 vol.%. The hydrocarbon gas has the highest content of CH4, which is distributed from 88.52% to 97.86 vol.%, and the content of other hydrocarbon gases is relatively low. The studied natural gas is mainly dry gas, and a small part is wet gas. According to the hydrocarbon gas component and carbon isotope analysis results, it showed that the natural gas of the Xujiahe Formation was a thermogenic gas, and there was no mixing of biogenetic gas. The natural gas was derived from the thermal degradation of the humus kerogen. Moreover, the rare gas in the natural gas of the Xujiahe Formation is a crustal origin organic gas, and there is no mantle origin gas, which indicates the lack of inorganic components in the natural gas. We also found that the CO2 in the natural gas is mainly inorganic gas, which is derived from the dissolution of carbonate minerals; and only a small part is organic thermogenic gas, which is derived from the thermal maturation process of organic matter. [ABSTRACT FROM AUTHOR]

In this paper, a Three-Port Dual Boost (TPDB) DC-DC converter operated Hybrid Electric Vehicle (HEV) based on dual motor drive system is presented to minimize Carbon Dioxide (CO2) emission and to increase the fuel efficiency. The Dual Drive Hybrid Electric Vehicle (DDHEV) system composed of Photovoltaic (PV) system/plug-in, dual drive system and power management algorithm improves the fuel efficiency of the DDHEV. The DDHEV system designed with the PV system needs efficient and simple DC-DC converter to export the power generated by the PV system to motor/battery. The simulation results of the HEV structured in the MATLAB/Simulink and the experimental prototype models are introduced to evaluate the proposed PV-DDHEV under various conditions. From the results, it is found that the dual motor drive system operated by the TPDB provides better stability and reduces the power consumption. [ABSTRACT FROM AUTHOR]

One of the important parameters illustrating the mass transfer process is the diffusion coefficient of carbon dioxide which has a great impact on carbon dioxide storage in marine ecosystems, saline aquifers, and depleted reservoirs. Due to the complex interpretation approaches and special laboratory equipment for measurement of carbon dioxide-brine system diffusivity, the computational and mathematical methods are preferred. In this paper, the adaptive neuro-fuzzy inference system (ANFIS) is coupled with five different evolutionary algorithms for predicting the diffusivity coefficient of carbon dioxide. The R2 values forthe testing phase are 0.9978, 0.9932, 0.9854, 0.9738 and 0.9514 for ANFIS optimized by particle swarm optimization (PSO), genetic algorithms (GA), ant colony optimization (ACO), backpropagation (BP), and differential evolution (DE), respectively. The hybrid machine learning model of ANFIS-PSO outperforms the other models. [ABSTRACT FROM AUTHOR]

Recently attention to the enhancement of oil recovery processes increases because of increasing energy demand and problems of declination of reservoirs. One of the effective and applicable approaches in the enhancement of oil recovery is carbon dioxide injection which also has a positive effect on the environment. The carbon dioxide injection can enhance oil recovery by various approaches. The extraction of lighter components of crude oil is known as one of the effects of carbon dioxide injection. The solubility of hydrocarbons in carbon dioxide is known as one of the dominant factors which can influence the hydrocarbon extraction from crude oil. Due to the importance of this parameter, in the present paper, Adaptive neuro-fuzzy inference system (ANFIS) joint with Genetic algorithm (GA) was developed to forecast the solubility of hydrocarbon in carbon dioxide based on carbon number of alkane, carbon dioxide density, pressure, and temperature. The ANFIS-GA solubility values were compared with the real solubility values. The determined coefficients of determination for training and testing phases are 0.96741 and 0.91648, respectively. So it is obvious the model has great capacity in the prediction of solubility. [ABSTRACT FROM AUTHOR]

Environmental concerns from global warming and climate change demand carbon dioxide separation from post-combustion gases. Important parameters are involved in choosing the suitable solvent for carbon dioxide separation, including the reaction rate of carbon dioxide and the solvent. In this paper, the kinetics of carbon dioxide (CO2) absorption in aqueous solutions of Monoethanolamine (MEA) + 1,3-Diaminopropane (DAP), a diamine containing two primary amino group, was developed. The measurements were performed in a stirred cell with a horizontal gas-liquid interface in the temperature range of 313.15–333.15 K and aqueous solutions of 10 wt% MEA + 5 wt% DAP and 12.5 wt% MEA + 2.5 wt% DAP. Experiments were conducted in an isothermal batch reactor with a horizontal gas-liquid interface under pseudo-first-order conditions, enabling the determination of the overall kinetic rate constant from the pressure drop method. Second-order reaction rate constants of CO2 absorption in amine solutions were estimated using the calculated initial absorption rate. It was found that the rate constants in MEA+ DAP solutions were greater than in MEA solutions which means that DAP increases the reaction rate. [ABSTRACT FROM AUTHOR]

Increasing population in many countries consumed natural resources and generates secondary product. These secondary products may be in the form of pollutants and liberated in the atmosphere. In this paper, an analysis was performed for green house gas (GHG) emission from municipal solid waste disposal for Faridabad city, India. Land filling and waste-to-energy methods were considered for GHG emission and analysis was performed based on Intergovernmental Panel on Climate Change (IPCC) model. GHG emission and linear pinch analysis (LPA) were performed based on the 50% collection efficiency in Faridabad city over a period of 10 years (2015–2025). Two scenarios of emission forecasting, such as land filling and waste to energy (incineration), were incorporated in this study. Hybrid analysis was presented for emission forecasting and emission reduction to develop a sustainable municipal solid waste management system for Faridabad. A target of 20% and 30% reduction in GHG emission was formulated with the help of LPA. The result shows that GHG in Faridabad city has been continuously changed from 2015 to 2025.The result represented here could be a decision support matrix for municipalities to develop integrated municipal solid waste management system for upcoming smart cities in India. Moreover, another novelty of this study reflects that cities having approximate same population, waste characteristics, and waste management technology could adopt this model for saving of GHG inventory and target-based reduction. [ABSTRACT FROM AUTHOR]

This paper examines the relationship among carbon dioxide (CO2) emissions, GDP, and energy in the Middle East and North Africa (MENA) countries by using a Responsiveness Scores (RS) approach. Empirical results over the period 1971–2013 suggest that GDP per capita and energy consumption show positive RSs, while trade and urban population negative ones. Moreover, energy consumption and urban population reveal moderate increasing returns to scale, while GDP per capita exhibits decreasing positive returns. Furthermore, three-way factors analysis sets out that most of the countries lays on regions with moderate negative Total Responsiveness Scores (TRS). This means that when all factors are jointly increased, CO2 emissions have a moderate decrease. In addition, some GCC countries present a different pattern compared to the average pattern of MENA countries. Finally, radar plots indicate that, overall, RS pattern over factors is moderately heterogeneous within GCC countries, with larger variability appearing in the response to urban population and GDP. [ABSTRACT FROM AUTHOR]

Poor solubility of substantial hydrocarbons in CO2 has constrained the use of CO2-EOR (enhanced oil recovery) in the modern oil recovery industry to some extent. Subsequently, it is significant to research the solubility regularity of various hydrocarbons in supercritical carbon dioxide (scCO2) in the first place. CO2 injection as one of the popular methodologies in light of financially and environmentally friendly has wide applications in EOR. In this paper, our objective is to estimate the solubility of n-alkanes in scCO2. This study highlights the application of a model based on least square support vector machine for estimation of solubility of n-alkanes in scCO2. The tuning parameters of the developed model were determined by an optimization algorithm, namely coupled simulated annealing. A set of 184 data points of solubility was used to execute the new model. To assess the accuracy and effectiveness of the developed model for prediction of experimental data, statistical and graphical techniques were used. Moreover, the outcomes were compared with the results of literature correlations to predict the solubility of alkanes. Results demonstrate that the model is precise and viable for prediction of solubility data. The resulted values of R2, root-mean-square error, SD, and % average absolute relative deviation for total data points are 0.99204, 0.12862, 0.6437, and 0.7753 for overall data, respectively. [ABSTRACT FROM AUTHOR]

It is known that in-vehicle carbon dioxide (CO2) concentration tends to increase due to occupant exhalation when the HVAC (heating, ventilation, and air conditioning) air is in recirculation mode. Field experiments were conducted to measure CO2concentration during typical commute in Bangkok, Thailand. The measured concentrations agreed with the concentration predicted using first-order mass balance equation, in both recirculating and outside air modes. The long-term transient decay of the concentration when the vehicle was parked and the HVAC system was turned off was also studied. This decay was found to follow Fickian diffusion process. The paper also provides useful operational details of the automotive HVAC system and fresh air ventilation exchange between cabin interior and exterior. Implications: Drivers in tropical Asian countries typically use HVAC recirculation mode in their automobiles. This behavior leads to excessive buildup of cabin CO2concentration levels. The paper describes the CO2buildup in a typical commute in Bangkok, Thailand. Auto manufacturers can potentially take measures to alleviate such high concentration levels. The paper also discusses the diffusion of CO2through the vehicle envelope, an area that has never been investigated before. [ABSTRACT FROM AUTHOR]

This paper explores the metafrontier environmental efficiency and group frontier environmental efficiency of the governments of the countries in Asia, the Americas, and Europe, adopting the directional distance function along with metafrontier analysis. The paper develops a new approach to measure technology heterogeneity between the environmental efficiency of the metafrontier and that of the group frontiers, namely technology gap. The 65 countries selected for this study include not only the countries in Annex B of the Kyoto Protocol, but also countries in Asia, the Americas, and Europe. According to the average values for environmental efficiency, based on these geographical locations, the empirical results show that European countries are superior to Asian and American countries, regardless of the environmental efficiency of the metafrontier or group frontiers. Also, the technology heterogeneity of European countries is lower than that of the other countries. [ABSTRACT FROM PUBLISHER]

In this paper, we aimed to investigate the relationship between energy consumption and carbon dioxide (CO2) emission quantities. To explain the dependence structure, we employed asymmetric Archimedean copulas and determined the best fitting multi-parameter Archimedean copula based on the λ–function. A goodness-of-fit improvement can be obtained by using concordance invariant and tail dependence preserving transforms. The association of CO2 emission quantities and energy consumption is characterized by the transformed convex sum of the Gumbel and Clayton copula, indicating evidence of joint extreme occurrences when both of the variables increase or decrease in the industrial sector. Also, the Kendall hazard scenario approach was used to evaluate the probability of extreme events. The results provide valuable information for researchers who model changes in CO2 emission quantities with energy consumption. [ABSTRACT FROM AUTHOR]

The Environmental Kuznets Curve hypothesis suggests that sustainable economic growth can be achieved in transitional countries after the threshold level of per capita income. And trade openness is also one of the critical factors to help transitional economies reduce carbon dioxide emissions and economic growth simultaneously through the combination of scale, composition, and technique effects. This paper is designed to explore the effect of trade openness on the environmental quality and investigate the existence of the environmental Kuznets curve hypothesis for a panel of CIS countries over the period of 2000–2013. The two-equation model is used to estimate the direct effect of trade openness on CO2 emissions and the indirect effect via per capita income. The instrumental variable techniques are employed to consider for endogeneity of per capita income and trade openness to estimate the indirect effect, and GLS analysis is conducted to estimate the direct effect of trade openness on CO2 emissions. The result shows that trade openness increases CO2 emissions directly while indirectly decreasing it due to its negative effect on per capita income. This study provides multiple policy implications for the sample countries to help them achieve sustainable economic growth while improving environmental quality. [ABSTRACT FROM AUTHOR]

Condensation of high-pressure refrigerants in small-diameter channels over a wide range of reduced pressures approaching the critical point is investigated in this two-part study. Part I presented pressure drop measurements and a two-phase pressure drop model. In this paper, Part II of the study, a condensation heat transfer model is presented. Heat transfer coefficients were measured during condensation of R404A in circular channels (inner diameter = 0.86, 1.55, 3.05 mm) over the entire quality range. The saturation temperature was varied from 30 to 60°C, and mass flux from 200 to 800 kg m-2 s-1, to evaluate their effects on condensation heat transfer coefficient. The heat transfer model is developed using a microchannel flow regime map and the void fraction model previously developed by the authors. The resulting model predicts 93.6% of the data within ±25%. The model exhibited good agreement with data from condensing ammonia and carbon dioxide, predicting 84.8% and 97% of their data within ±25%, respectively. [ABSTRACT FROM AUTHOR]

Maritime greenhouse gas emissions are projected to increase significantly by 2050, highlighting the need for reliable inventories as a first step in analyzing ship emission control policies. The impact of ship power models on marine emissions inventories has garnered little attention, with most inventories employing simple, load-factor-based models to estimate ship power consumption. The availability of more expansive ship activity data provides the opportunity to investigate the inventory impacts of adopting complex power models. Furthermore, ship parameter fields can be sparsely populated in ship registries, making gap-filling techniques and averaging processes necessary. Therefore, it is important to understand of the impact of averaged ship parameters on ship power and emission estimations. This paper examines power estimation differences between results from two complex, resistance-based and two simple, load-factor-based power models on a baseline inventory with unique ship parameters. These models are additionally analyzed according to their sensitivities toward average ship parameters. Automated Identification System (AIS) data from a fleet of commercial marine vessels operating over a 6-month period off the coast of the southwestern United States form the basis of the analysis. To assess the inventory impacts of using averaged ship parameters, fleet-level carbon dioxide (CO2) emissions are calculated using ship parameter data averaged across ship types and their subtype size classes. Each of the four ship power models are used to generate four CO2 emissions inventories, and results are compared with baseline estimates for the same sample fleet where no averaged values were used. The results suggest that a change in power model has a relatively high impact on emission estimates. They also indicate relatively little sensitivity, by all power models, to the use of ship characteristics averaged by ship and subtype. Implications: Commercial marine vessel emissions inventories were calculated using four different models for ship engine power. The calculations used 6 months of Automated Identification System (AIS) data from a sample of 248 vessels as input data. The results show that more detailed, resistance-based models tend to estimate a lower propulsive power, and thus lower emissions, for ships than traditional load-factor-based models. Additionally, it was observed that emission calculations using averaged values for physical ship parameters had a minimal impact on the resulting emissions inventories. [ABSTRACT FROM AUTHOR]

This work reports on the use of pressurized CO2 pretreatment to improve methane yield and pathogen indicator organism die-off in co-settled sewage sludge (SS). Four semi-continuous mesophilic anaerobic digesters were fed on co-settled SS to establish a baseline for performance and stability. One pair of digesters was then fed with co-settled SS pretreated by P CO2 at 2800 kPa for 23 h. The trial continued for 70 days during which specific biogas and methane production, volatile solids destruction and loss of viability of Escherichia coli was monitored in test and control digesters. The pretreatment had no positive influence on any of these parameters, which was further confirmed using batch biochemical methane potential tests and direct measurement of die-off of E. coli and Salmonella enterica in samples of different sizes treated in pressure vessels of different sizes and in matrices of nutrient medium and co-settled SS. Pressurised CO2 pretreatment was effective at killing fecal indicator bacteria in nutrient medium but ineffectual in SS, strongly suggesting that the nature of suspending matrix was a principle determining factor. Paper concludes that pressurized CO2 pretreatment is not a satisfactory approach to improve either biogas production or pathogen destruction in anaerobic digestion. [ABSTRACT FROM AUTHOR]

Background/rationale: The carbon dioxide (CO2) challenge has been reliably used in laboratory settings as a panicogen in clinical populations. However, the magnitude of these effects on healthy and non-clinical control populations are not clear. The aim of this meta-analysis and systematic review is to provide quantitative estimates of those effects. Specifically, the current paper will evaluate the relative efficacy of the CO2 challenge in eliciting both subjective and physiological arousal in healthy and non-clinical control populations.Method: A total of 16 articles with 35 independent samples were included in the meta-analysis, while 37 studies with 74 independent samples were included in the systematic review.Results: Both the meta-analysis and systematic review found the CO2 challenge to elicit an increase in subjective distress via self-reported anxiety and fear. Physiological responses via blood pressure and heart rate were heterogeneous in studies sampled, with no significant changes observed across studies. Moderator analyses revealed the variations in findings may be attributed to participant screening and invasive sampling.Discussion: Findings highlight the CO2 challenge as a useful tool in the provocation of subjective distress. Implications for both the use of the CO2 challenge and its anticipated effects in healthy and non-clinical control populations are discussed. [ABSTRACT FROM AUTHOR]

This paper examines long-run and short-run dynamics of renewable energy consumption on carbon dioxide (CO2) emissions and economic growth in the European Union. This study employs cointegration tests, Granger causality tests and vector error correction estimates to examine the direction of Granger causality, the long-run dynamics of economic growth and energy variables on carbon emissions. This study analyses time series data from the World Development Indicators over the period from1961 to 2012. The results of this study support a link between renewable energy consumption, economic growth, industrialization, exports and CO2 emissions in the long-run and short-run. The results support that the sign of the long-run dynamics from the endogenous variables to the CO2 emissions variable is negative and significant, which implies that the energy and environmental policies of the European Union aimed at curbing CO2 emissions must have been effective in the long-term. Furthermore, renewable energy consumption and exports have significant negative impact on CO2 emissions in the short-run. However, industrialization and economic growth have positive impact on CO2 emissions in the short-run. The results suggest that both economic growth and industrialization must have been achieved at the cost of harming the environment. The finding suggests that the increasing consumption of renewable energy tends to play an important role in curbing carbon emissions in the region. [ABSTRACT FROM AUTHOR]