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Due to its cost-effectiveness and high product selectivity, tin oxide has been regarded as a promising catalyst for the electrochemical conversion of CO2 to formate. However, formate production is hindered by the high overpotential; there is a need to reduce the overpotential to enhance energy efficiency and lower electricity cost for the implementation of carbon utilization technology. Here, we report a facile synthesis method for 1 nm-sized SnO2 cluster catalysts, which can be used for CO2-to-formate conversion. SnO2 clusters were prepared through impregnation of porous carbon with a tin precursor solution. The SnO2 clusters showed a low overpotential, generating a current density of 10 mA cm-2 at a potential of -0.34 V vs. RHE in 1 M KOH. They also achieved high Faradaic efficiencies of 90.5% and 81.5% at 200 and 300 mA cm−2, respectively. Their electrocatalytic performance was strongly dependent on the annealing conditions, which affected the particle size, electrochemical active surface area, and metal oxidation state. This paper presents a versatile method for synthesizing metal oxide cluster catalysts, apart from providing insights into the catalytic activity for the electrochemical conversion of CO2 to formate. [ABSTRACT FROM AUTHOR]

In order to study the performance of partially precast partially encased assembled composite beam (PPECB) in reducing costs and reducing carbon dioxide (CO2) emissions, this paper obtained the bearing capacity of PPECBs by a static test. Considering the load conditions and beam height conditions as constraints, the steel-concrete composite beam (SCCB) and reinforced concrete beam (RCB) were optimized and designed based on the principle of fully utilizing the advantages of steel and concrete. On the basis of investigating the quantity of different materials, the cost and CO2 emissions of the three different types of beams were analyzed. The cost and CO2 emission of the PPECB are the lowest, and SCCBs have the highest cost and CO2 emissions. This paper can provide reference for design choice and further research from the perspective of cost and CO2 emission and lay a solid foundation for the realization of economic and environment-friendly buildings. [ABSTRACT FROM AUTHOR]

The increasing carbon dioxide content is identified as the main cause of global warming. Capturing carbon dioxide in the atmosphere and transporting it to deep salt layer for storage have been proven and practiced in many aspects, which considered to be an effective way to reduce the content of carbon dioxide in the atmosphere. The sealing property of cap rocks is one of the key factors to determine whether CO2 can be effectively stored for a long time. In view of the disadvantages of tedious and time-consuming laboratory test methods for breakthrough pressure of cap rock, this paper explores the relationship between breakthrough pressure and other parameters such as porosity, permeability, density, specific surface area, maximum throat radius, and total organic carbon. The results show that the rock breakthrough pressure is closely related to the maximum throat radius and permeability determined by the mercury injection method, followed by the porosity and specific surface area, and less related to the density, depth, and TOC content of the rock itself. Then, with the selected parameters, a neural network model is established to predict the breakthrough pressure of cap rock, which can achieve good prediction results. [ABSTRACT FROM AUTHOR]

The scroll-type compressor is the core component of the refrigeration system using the natural refrigerant carbon dioxide. An accurate scroll geometric theoretical model is essential for evaluating and enhancing compressor performance. The present paper proposed and validated an improved geometric theoretical model of a scroll compressor. A vector triangle method-based general piecewise function describes precisely the volume variation of the working chambers, based on which the transient throughflow modeling and performance evaluation of a carbon dioxide scroll compressor were conducted. The mechanisms and influencing factors of the suction precompression and the asymmetry discharging were analyzed. The results indicate that the strength of the suction precompression is mainly influenced by the suction vacuum under different rotating speeds, partly associated with the tangential leakage under low rotating speeds. The increasing initial suction pressure contributes to the linear raising of the pressure difference between suction initial and ending pressures, decreasing the precompression extension slightly. The variation of the discharge throughflow areas of two symmetric discharge chambers dominates the pressure asymmetry, which is gradually eliminated by the overlapping throughflow area. Compared with the circular discharge structure, the waist-shape port reduces the pressure asymmetry degree and shortens its duration. [ABSTRACT FROM AUTHOR]

This paper proposes an oxygen and carbon dioxide concentration monitoring system for freshness management based on radio frequency identification (RFID). Freshness can be checked by various factors including humidity, temperature, oxygen, and carbon dioxide. This paper focuses on oxygen and carbon dioxide. The concentrations of these two gases are related to freshness and affect the food. We use a sensor for monitoring these gases and combine the sensor with an RFID tag. The RFID system is relatively easy to manage. With this combined system, we estimated the freshness of vegetables. [ABSTRACT FROM AUTHOR]

Under the situation of global low-carbon development, the contradiction among energy consumption, economic growth, and CO2 emissions is increasingly prominent. Considering the possible two-way feedback among the three, based on the panel data of 30 regions in China from 2000 to 2017, this paper establishes a spatial Durbin model including economic growth, energy consumption equation, and CO2 emissions and studies the dynamic relationship and spatial spillover among economic growth, energy consumption, and CO2 emissions effects. The results show that the economic growth can significantly improve carbon dioxide emissions, and China's economic growth level has become a positive driving force for carbon dioxide emissions. However, economic growth will not be significantly affected by the reduction of carbon dioxide emissions. There is a two-way relationship between energy consumption (ENC) and carbon dioxide emissions (CO2). Energy consumption and carbon emissions are interrelated, which has a negative spatial spillover effect on the carbon dioxide emissions of the surrounding provinces and cities. [ABSTRACT FROM AUTHOR]

In the field of condition-based maintenance, maintenance costs and system reliability criteria are the primary considerations for traditional maintenance management. These methods lack consideration of the environmental impact caused by equipment degradation, such as excessive emissions and energy consumption. In addition, because equipment degradation has various impacts on the ecological environment, companies with excessive emissions and energy consumption can receive huge fines, making it of great value to study ecoconscious maintenance strategies. In this paper, we propose a condition-based maintenance strategy considering energy consumption and carbon dioxide emissions. The major objective of the research is to extend a model which integrates ecological aspects with maintenance decision-making and optimization. The simulation and sensitivity analyses conducted verify that the model proposed can minimize total costs, as well as the environmental impact. [ABSTRACT FROM AUTHOR]

In this paper, the inerting effect and migration law of inert N2 and CO2 in large inclined goaf are studied using a physical simulation model. The differences in oxygen reduction and inert gas migration are analyzed and compared. The results show that as N2 and CO2 injection increased, the oxidation zone's range and width shrunk, and the end of the loose and oxidation zones moved closer to the working face. The migration profile of CO2 and N2 resembled a trumpet and an L shape, respectively, and under the same inerting flow rate, the effect of CO2 inerting on oxygen reduction was much less significant than that of N2. [ABSTRACT FROM AUTHOR]

Since China's reform and opening up, the social economy has achieved rapid development, followed by a sharp increase in carbon dioxide (CO2) emissions. Therefore, at the 75th United Nations General Assembly, China proposed to achieve carbon peaking by 2030 and carbon neutrality by 2060. The research work on advance forecasting of CO2 emissions is essential to achieve the above-mentioned carbon peaking and carbon neutrality goals in China. In order to achieve accurate prediction of CO2 emissions, this study establishes a hybrid intelligent algorithm model suitable for CO2 emissions prediction based on China's CO2 emissions and related socioeconomic indicator data from 1971 to 2017. The hyperparameters of Least Squares Support Vector Regression (LSSVR) are optimized by the Adaptive Artificial Bee Colony (AABC) algorithm to build a high-performance hybrid intelligence model. The research results show that the hybrid intelligent algorithm model designed in this paper has stronger robustness and accuracy with relative error almost within ±5% in the advance prediction of CO2 emissions. The modeling scheme proposed in this study can not only provide strong support for the Chinese government and industry departments to formulate policies related to the carbon peaking and carbon neutrality goals, but also can be extended to the research of other socioeconomic-related issues. [ABSTRACT FROM AUTHOR]

Carbon dioxide phase transition fracturing is a novel physical blasting technique, which is gradually used in mining and underground space engineering. The improvement of its rock breaking efficiency is the key concern in the application. In this paper, field experiments of CO2 phase transition fracturing were conducted. Based on the strain monitoring and fracturing crater volume measuring, the variation of CO2 filling amount and shear sheet thickness on rock fragmentation of CO2 phase transition fracturing was investigated. The experimental results indicated that the fracturing crater is shaped as an elliptical cone that is longer in the jet direction and shorter in the vertical jet direction. With the increase of the CO2 filling amount, the excavated crater volume gradually increases, but the growth rate gradually decreases. The powder factor is constant within a certain charge amount, and after exceeding this charge amount, the powder factor of CO2 increases significantly. As the shear sheet thickness increases, although the consultant peak stress gradually increases, its growth rate is still unchanged. The crater volume and its growth rate gradually increase in the same situation. Moreover, with the shear sheet thickness increase, the CO2 powder factor decreases continuously, and the decline rate remains unchanged. [ABSTRACT FROM AUTHOR]

Acid gases, such as CO2, H2S, and/or sulfur in oil industry’s production fluids, can be responsible for both general and localized corrosion, acting with different mechanisms, which depend on chemical and physical properties of the produced fluids. Materials selection for handling such fluids is performed by combining experience with suggestions from standards and regulations. A good deal of knowledge is available to predict corrosion rates for CO2-containing hydrocarbons, but the effect of high H2S pressure is less understood, mainly due to the difficulty of performing laboratory tests in such challenging conditions. For instance, the so-called NACE solution to assess SSC (Sulfide Stress Cracking) susceptibility of steels is a water-based solution simulating production fluids in equilibrium with one bar bubbling H2S gas. This solution does not represent environments where high gas pressure is present. Moreover, it does not take into account the corrosive properties of sulfur and its compounds that may deposit in such conditions. Besides, properties of high pressure gases are intermediate between those of a gas and those of a liquid: high pressure gases have superior wetting properties and better penetration in small pores, with respect to liquids. These features could enhance and accelerate damage, and nowadays such conditions are likely to be present in many production fields. This paper is aimed to point out a few challenges in dealing with high pressure gases and to suggest that, for materials selection in sour service, a better correspondence of test conditions with the actual field conditions shall be pursued. [ABSTRACT FROM AUTHOR]

In order to solve the problem of hydrate reservoir collapse and hydrate regenerated in the process of solid fluidization of natural gas hydrate, a new method of natural gas hydrate exploit by high‐polymer additive (low viscosity carboxymethyl cellulose LV‐CMC) carbon dioxide jet was proposed. The wellbore temperature and pressure changes during this process are analyzed, and the wellbore temperature and pressure model are established and solved by the state space method. This paper also analyzed the effects of relevant parameters on hydrate decomposition, such as injection flow, temperature, and pressure. The results show that increasing the injection pressure allows the hydrate decomposition site to be closer to the annulus outlet. Compared with water, with polymer additive CO2 fluid as the drilling fluid, the intersection point of phase equilibrium curve and annular pressure curve is closer to annular outlet, which is obviously more conducive to well control. In order to avoid phase changes, the injection pressure of the carbon dioxide fluid of the high‐polymer additive should not be lower than 10 MPa, and the injection temperature should not be higher than 285 K. [ABSTRACT FROM AUTHOR]

Injecting CO2 into a reservoir disturbs the geostress field, which leads to variations in the permeability of caprock and affects its sealing performance. In this paper, the evolution characteristics of the permeability of Yingcheng mudstone were experimentally studied during deviatoric compression under different confining pressures. As the confining pressure increased, the strength of the mudstone increased bilinearly, the angle between the fault and the maximum principle stress increased, and the fault became flatter. During compression, the permeability of mudstone first decreased and then increased and the turning point of the permeability was between the onset of dilatancy and the turning point of volumetric strain; when the fault formed, the permeability increased sharply and the fault-induced increment was reduced exponentially with increasing confining pressure. In addition, the mudstone transformed to the ductile failure mode when the effective confining pressure was greater than 35 MPa, which means that the permeability did not jump within a small strain. Finally, a practical strain-based model of permeability evolution that separately considers compaction and dilatancy was proposed, and the predicted permeability values were in good agreement with the experimental results. This study revealed the effect of confining pressure on permeability evolution during compression and can help evaluate the sealing ability of mudstone caprock. [ABSTRACT FROM AUTHOR]

In order to ensure high-quality and on-time delivery in logistic distribution processes, it is necessary to efficiently manage the delivery fleet. Nowadays, due to the new policies and regulations related to greenhouse gas emission in the transport sector, logistic companies are paying higher penalties for each emission gram of CO2/km. With electric vehicle market penetration, many companies are evaluating the integration of electric vehicles in their fleet, as they do not have local greenhouse gas emissions, produce minimal noise, and are independent of the fluctuating oil price. The well-researched vehicle routing problem (VRP) is extended to the electric vehicle routing problem (E-VRP), which takes into account specific characteristics of electric vehicles. In this paper, a literature review on recent developments regarding the E-VRP is presented. The challenges that emerged with the integration of electric vehicles in the delivery processes are described, together with electric vehicle characteristics and recent energy consumption models. Several variants of the E-VRP and related problems are observed. To cope with the new routing challenges in E-VRP, efficient VRP heuristics and metaheuristics had to be adapted. An overview of the state-of-the-art procedures for solving the E-VRP and related problems is presented. [ABSTRACT FROM AUTHOR]

This paper presents the results of an evaluation study of gas drainability in the Bulli seam in the Southern Coalfield of the Sydney Basin, NSW, Australia, where the coal seam gas (CSG) contains a high proportion of carbon dioxide (CO2). Historically the gas drainability in some particular areas of this coal seam was found to be particularly poor, which posed a significant challenge to gas predrainage. As a result, a large volume of greenhouse gases were released to the atmosphere during mining of the coal seam. Furthermore, the high gas content associated with the CO2-rich composition also increased the risks of coal and gas outburst incidents, affecting the safety of mining. After systematic literature review of evaluation factors affecting gas drainability, this evaluation study comprehensively analyzed the main critical factors, including the geology of the area, the coal cleat system, coal microstructure, coal permeability, coal sorption capacity, gas content, and gas composition. Field geology analysis showed geological variations that affected the variations of the coal cleat system and CO2 content in the coal seam. Scanning Electron Microscope (SEM) tests showed the tight and less-porous features in hard-to-drain coal samples. The colliery gas database analysis was carried out to assess the impact of gas content and gas composition on the drainability of the coal seam. Laboratory tests showed that the coal seam had a permeability of less than 1 mD and also showed that the coal seam was highly undersaturated, especially with high CO2 content. [ABSTRACT FROM AUTHOR]

Blended cements are preferred to Ordinary Portland Cement (OPC) in construction industry due to costs and technological and environmental benefits associated with them. Prevalence of significant quantities of carbon dioxide (CO2) in the atmosphere due to increased industrial emission is deleterious to hydrated cement materials due to carbonation. Recent research has shown that blended cements are more susceptible to degradation due to carbonation than OPC. The ingress of CO2 within the porous mortar matrix is a diffusion controlled process. Subsequent chemical reaction between CO2 and cement hydration products (mostly calcium hydroxide [CH] and calcium silicate hydrate [CSH]) results in degradation of cement based materials. CH offers the buffering capacity against carbonation in hydrated cements. Partial substitution of OPC with pozzolanic materials however decreases the amount of CH in hydrated blended cements. Therefore, low amounts of CH in hydrated blended cements make them more susceptible to degradation as a result of carbonation compared to OPC. The magnitude of carbonation affects the service life of cement based structures significantly. It is therefore apparent that sufficient attention is given to carbonation process in order to ensure resilient cementitious structures. In this paper, an indepth review of the recent advances on carbonation process, factors affecting carbonation resistance, and the effects of carbonation on hardened cement materials have been discussed. In conclusion, carbonation process is influenced by internal and external factors, and it has also been found to have both beneficial and deleterious effects on hardened cement matrix. [ABSTRACT FROM AUTHOR]

The role of nuclear energy is to supply electric power on a stable basis to meet increasing demands, reduce carbon dioxide emissions, and maintain stable electric power costs while ensuring safety. The Fukushima accident taught us many lessons for creating safer nuclear power plants. Considering the design of systems, the areas of weakness at the Fukushima nuclear power plants can be divided into three categories: plant protection, electricity supply, and cooling of the nuclear fuel. In this paper, focusing on these three areas, the lessons learned are proposed and applied for pressurized heavy water reactors. Firstly, hard protection against external risks ensures the integrity of components and systems such that they can perform their original functions. Secondly, additional emergency power supply systems for electrical redundancy and diversity can improve the response capabilities for an accident by increasing the availability of active components. Thirdly, cooling for removing decay heat can be augmented by adopting diverse safety systems derived from other types of reactors. This study is expected to contribute to the safety enhancement of pressurized heavy water reactors by applying design changes based on the lessons learned from the Fukushima accident. [ABSTRACT FROM AUTHOR]

Microalgae are one of the most promising feedstocks for biodiesel production due to their high lipid content and easy farming. However, the extraction of lipids from microalgae is energy intensive and costly and involves the use of toxic organic solvents. Compared with organic solvent extraction, supercritical CO2 (SCCO2) has demonstrated advantages through lower toxicity and no solvent-liquid separation. Due to the nonpolar nature of SCCO2, polar organic solvents such as methanol may need to be added as a modifier in order to increase the extraction ability of SCCO2. In this paper, pilot scale lipid extraction using SCCO2 was studied on two microalgae species: Spirulina sp. and Schizochytrium sp. For each species, SCCO2 extraction was conducted on 200 g of biomass for 6 h. Methanol was added as a cosolvent in the extraction process based on a volume ratio of 4%. The results showed that adding methanol in SCCO2 increased the lipid extraction yield significantly for both species. Under an operating pressure of 4000 psi, the lipid extraction yields for Spirulina sp. and Schizochytrium sp. were increased by 80% and 72%, respectively. It was also found that a stepwise addition of methanol was more effective than a one-time addition. In comparison with Soxhlet extraction using methylene chloride/methanol (2:1, v/v), the methanol-SCCO2 extraction demonstrated its high effectiveness for lipid extraction. In addition, the methanol-SCCO2 system showed a high lipid extraction yield after increasing biomass loading fivefold, indicating good potential for scaling up this method. Finally, a kinetic study of the SCCO2 extraction process was conducted, and the results showed that methanol concentration in SCCO2 has the strongest influence on the lipid extraction yield. [ABSTRACT FROM AUTHOR]

We introduce different ways to solve the actual fragility problem of the epoxy-amine polymers by curing epoxidian oligomers with aliphatic amines without additional heat input. The pathways are the oligomer-oligomeric modification of epoxy resins-epoxy oligomers (EO), with their conversion to oligoethercyclocarbonates (OECC) by carbonization with carbon dioxide. The cocuring of these oligomers as a result of aminolysis competing reactions is “epoxide-amine” (forming a network polymer) and “cyclocarbonate-amine” (forming the linear hydroxyurethane, extending the internodal chains). Formation of internal and intermolecular hydrogen bonds was established on hydroxycarbonates (HA) and linear polyhydroxyurethanes (PHU) model compounds by IR and NMR spectroscopy. The results of the hydrogen bond system formation processes explain the change in the relaxation and physicomechanical properties of hard polymers modified by the epoxy-amine compositions (OECC), containing aromatic and aliphatic links. This paper presents a possible OECC modificator, the optimal EO:OECC ratio and its influence on the cross-link frequency, the polarity, the fragment and chain flexibilities and, as a consequence, the possible stiffness regulation for selected epoxy polymers. Thus, the causes of the increase in deformation-strength and adhesion characteristics were established by a factor of 1.5 to 3.0 due to an increase in cohesive strength (as a result of the combined network operation with covalent and physical bonds), as well as reduction of residual stresses (by adding the aliphatic fragments as additional relaxants), and reducing the defectiveness of the boundary layers (polymer-substrate). [ABSTRACT FROM AUTHOR]

Carbon footprint is one of the most widely used tools for assessing the environmental impacts of the production and utilization of concrete as well as of the components derived from it, representing the amount of carbon dioxide and other greenhouse gases associated with this product, expressed as CO2 equivalents. In this paper, carbon footprint was used to compare the environmental performance in the production phase of a concrete made with both recycled and crushed virgin limestone aggregates, using a life cycle analysis methodological approach. Research outcomes revealed, as expected, that carbon dioxide equivalent emissions decreased slightly as the use of recycled aggregates increased. Emissions for concrete with 0.5 w/c were between 347 and 351 kg of CO2-e/m3. It was also corroborated that cement is the material with the greatest influence on greenhouse gas emission generation in the concrete’s production phase, regardless of the use of recycled or virgin aggregates. [ABSTRACT FROM AUTHOR]

The CO2 formation during food storage can often be correlated with the increase in yeast population. Yogurt and other dairy products are susceptible to yeast contamination. Accumulation of CO2 in the headspace of yogurt packages can lead to the eventual blowing off of the package. Therefore, determination of CO2 in the yogurt packages can indicate eventual unsafety of the product. The aim of this paper was to determine CO2 concentration in the headspace of different yogurt containers contaminated with yeast at the levels of 1 and 5 CFU/ml. Yeast Candida kefyr, previously isolated from spoiled yogurt, was used for contamination. Contaminated and control samples of yogurt were incubated at 30°C. A device based on tunable diode laser absorption spectroscopy was used for the measurement of CO2 concentration. The CO2 content in all analysed samples changed in a similar manner with slow increase to the value of 6% during the first 30 h and, after that, rapid accumulation to 17–20%. The initial level of yeast contamination did not have significant influence to the CO2 content trend. The increase in the number of yeast was observed after 10 h of incubation, and the final value of 6-7 log·CFU/cm3 was reached after 40 h of incubation. The significant increase in the yeast number can be correlated with the CO2 content in a way that CO2 concentration of 6% can be considered as critical for microbial spoilage. Since the TDLAS technique is simple and nondestructive, it can be a promising possibility for detection of the microbial spoilage in food. [ABSTRACT FROM AUTHOR]

During catalytic cracking of methane reaction, different carbon nanostructures can be formed. This paper shows the results of a characteristic nanostructured carbon deposit obtained during cracking of methane reaction over nanocrystalline iron catalysts with or without cobalt addition. The properties of the carbon deposit were determined by X-ray diffraction, scanning electron microscope with energy dispersive spectrometer equipment, thermogravimetry-differential thermal analysis coupled with mass spectrometry, time-of-flight secondary ion mass spectrometry analysis and surface area analysis (Brunauer-Emmett-Teller isotherm [BET]). Significant differences in the morphology and properties of the obtained carbon were found. The mechanism of the formation of carbon nanostructures for both iron catalysts is proposed. [ABSTRACT FROM AUTHOR]

The increasing emission of carbon dioxide worldwide has emerged as a major global concern in the context of addressing climate change. Converting CO2 to high-value carbon materials is a promising solution to capture emitted carbon for achieving carbon neutrality. Furthermore, such conversion can provide carbon nanomaterials for key industries, including the lithium battery and fuel cell industries. Here, it is shown that sub-50 nm tangled carbon nanotubes (CNTs) can be synthesized by adjusting the metaborate concentration and the current density through the electrochemical conversion of carbon dioxide in a molten carbonate salt. The metaborate ion concentration affects the product selectivity and carbon morphology, and the current density is strongly related to the particle size of in situ seed catalysts supplied by the dissolution of an Ni-Fe-Cr alloy anode. The optimized process conditions control the nucleation and growth of carbon via a tip-growth mechanism, thereby promoting the formation of sub-50 nm CNTs rather than bulky irregular carbon particles. The Raman and Brunauer–Emmett–Teller analyses showed that the properties of the prepared CNTs depended on the synthetic parameters. This study provides deep insights into the mechanism underlying carbon synthesis through the electrochemical reduction of a molten carbonate salt. [ABSTRACT FROM AUTHOR]

Biomimetic membranes (BMM) based on polymer filters impregnated with lipids or their analogues are widely applied in numerous areas of physics, biology, and medicine. In this paper we report the design and testing of an electrochemical system, which allows the investigation of CO2 transport through natural membranes such as alveoli barrier membrane system and also can be applied for solid-state measurements. The experimental setup comprises a specially designed two-compartment cell with BMM connected with an electrochemical workstation placed in a Faraday cage, two PH meters, and a nondispersive infrared gas analyzer. We prove, experimentally, that the CO2 transport through the natural membranes under different conditions depends on pH and displays a similar behavior as natural membranes. The influence of different drugs on the CO2 transport process through such membranes is discussed. [ABSTRACT FROM AUTHOR]

The first ecological footprint calculation version, applied to companies, appeared in 2003. The said tool provides the possibility of calculating the total impact of a company or organisation in hectares or in equivalent emissions of CO2. This paper updates carbon absorption rates and improves electricity consumption conversion factors, one of the major footprint generating consumptions in companies. The new rates prove that the footprint estimated to date will be notably increased as, among other aspects, the IPCC has downgraded the amount of carbon that forests are capable of absorbing. These data reveal that companies must make a great effort to adapt to the challenges triggered by climate change. [ABSTRACT FROM AUTHOR]

This paper analyzes the time-varying impacts of Chinaʼs economic growth, energy efficiency, and industrial development on carbon dioxide (CO2) emissions from 1970 to 2019. First, we examined and found that there are two significant structural changes in the CO2 sequence over the years, and there was a significant nonlinear relationship among the four. The first nonlinear structural model constructed is the TVP regression model. According to the Bayesian model comparison criterion, TVP-SV-VAR was selected as the second constructed model from four types of VAR models containing nonlinear structures. The results show that the conduction intensity value of energy use efficiency to CO2 emissions has increased year by year, from 0.45 in 1971 to 0.97 in 2019. The short-term transmission mechanism of energy use efficiency to carbon emissions is the most significant. The conduction intensity of Chinaʼs economic growth on CO2 emissions increases year by year. Chinaʼs economic growth plays a major role in long-term CO2 emission reduction. The impact of industrial development on CO2 emissions reached a peak of 0.34 in 1977, and the intensity of the impact has basically stabilized at 0.26. [ABSTRACT FROM AUTHOR]

The recent failures in flexible pipes have motivated the exhaustive research of corrosion mechanisms on high-strength carbon steel armor wires that are the main structural compounds of those structures that mostly operate in seawater environments in the presence of carbon dioxide (CO2) and confined spaces. Recently, the literature reported discoveries about electrolyte properties (as Fe+2(aq)/HCO3-(aq.) ratio) and supersaturation, near neutral pH inside the confined space, multiphase reactions of contaminants present in CO2 gas, the formation and dissolution mechanism of FeCO3 film, and interaction of CO2 gas impurities with the corrosion scale. Therefore, this review is aimed at presenting an up-to-date narrative of the CO2 corrosion phenomenon in carbon steel, connecting background fundamentals with current data studies. [ABSTRACT FROM AUTHOR]

This paper is concerned with the mathematical modeling of a severe and common congenital defect called hypoplastic left heart syndrome (HLHS). Surgical approaches are utilized for palliating this heart condition; however, a brain white matter injury called periventricular leukomalacia (PVL) occurs with high prevalence at or around the time of surgery, the exact cause of which is not known presently. Our main goal in this paper is to study the hemodynamic conditions under which HLHS physiology may lead to the occurrence of PVL. A lumped parameter model of the HLHS circulation has been developed integrating diffusion modeling of oxygen and carbon dioxide concentrations in order to study hemodynamic variables such as pressure, flow, and blood gas concentration. Results presented include calculations of blood pressures and flow rates in different parts of the circulation. Simulations also show changes in the ratio of pulmonary to systemic blood flow rates when the sizes of the patent ductus arteriosus and atrial septal defect are varied. These changes lead to unbalanced blood circulations and, when combined with low oxygen and carbon dioxide concentrations in arteries, result in poor oxygen delivery to the brain. We stipulate that PVL occurs as a consequence. [ABSTRACT FROM AUTHOR]

Recent publications suggest that target end-tidal carbon dioxide concentrations should be higher than values currently considered as acceptable. This paper presents evidence that end-tidal carbon dioxide values higher than concentrations that are currently targeted result in improved patient outcomes and are associated with a reduced incidence of postoperative complications. [ABSTRACT FROM AUTHOR]

Using supercritical carbon dioxide (scCO2) as an alternative to conventional methods in the preparation of porous biodegradable polymer and polymer/nanocomposites for tissue engineering has attracted increasing interest in recent years due to the absence of using organic solvents and the ability to incorporate thermosensitive biologicals without loss of bioactivity. Additionally, scCO2 can exert a high level of control over porosity and morphology of scaffolds by tuning the processing parameters. This paper describes the newly achievements on the preparation of porous polymer materials using scCO2 foaming technology with focus on the porous biodegradable materials and its nanocomposites relevant to tissue engineering. [ABSTRACT FROM AUTHOR]

The emission of carbon dioxide (CO2) is closely associated with oxygen (O2) depletion, and thermal decomposition in a reacting stockpile of combustible materials like fossil fuels (e.g., coal, oil, and natural gas). Moreover, it is understood that proper assessment of the emission levels provides a crucial reference point for other assessment tools like climate change indicators and mitigation strategies. In this paper, a nonlinear mathematical model for estimating the CO2 emission, O2 depletion, and thermal stability of a reacting slab is presented and tackled numerically using a semi-implicit finite-difference scheme. It is assumed that the slab surface is subjected to a symmetrical convective heat and mass exchange with the ambient. Both numerical and graphical results are presented and discussed quantitatively with respect to various parameters embedded in the problem. [ABSTRACT FROM AUTHOR]

Objective. Our institution has been using a novel flexible laser fiber in pediatric surgical airway procedures, which has been quite successful. The purpose of this paper is to present our preliminary experience in the treatment of pediatric airway lesions using this laser technique. Methods. A case series reviewing 40 patients undergoing 95 laser procedures is reported. Indications included removal of suprastomal granulation tissue, removal of granulation after laryngotracheal reconstruction, subglottic and supraglottic stenoses, recurrent respiratory papillomas, subglottic hemangioma, laryngeal cleft, and left main stem bronchus stenosis. Procedures were performed via microdirect laryngoscopy and bronchoscopy. Results. No complications including postoperative glottic webs, concentric scar formation, or airway fires occurred in any of the patients (after the series was completed, we did experience an airway fire. It was a flash flame that was self-limited and caused no long-term tissue injury) . Conclusions. The endoscopic application of a new flexible carbon dioxide laser fiber for management of pediatric airways lesions provides good outcomes in selected patients. Distal respiratory papillomas, subglottic stenosis, and granulation tissue are, in our experience, appropriate indications. [ABSTRACT FROM AUTHOR]

The effect of an alkali treatment (potassium hydroxide) on the properties of a commercial activated carbon has been studied. The aim of the treatment was to improve the adsorption properties of the material toward carbon dioxide. In the result of the treatment, silica contained in the raw carbon was removed and the density of the material increased. The changes in the surface chemistry were observed as well. The treatment of the activated carbon with KOH resulted in a complete removal of carboxy and lactone groups and a decrease of the general content of the acidic groups (more significant than that of basic groups). Simultaneously, the surface concentration of hydroxyl groups increased. The alkali treatment of activated carbon resulted in an increase of carbon dioxide uptake of 14% (measured using a volumetric method at 0℃). The adsorption of carbon dioxide on activated carbon has a mixed (physicochemical) character and that two types of adsorption sites are present at the surface. The adsorption energy varies roughly from 25 to 60 kJ/mol. [ABSTRACT FROM AUTHOR]

This paper examines the effect of high-pressure carbon dioxide on the foaming process in polystyrene near the glass transition temperature and the foaming was studied using cylindrical high-pressure view cell with two optical windows. This technique has potential applications in the shape foaming of polymers at lower temperatures, dye impregnation, and the foaming of polystyrene. Three sets of experiments were carried out at operating temperatures of 50, 70, and 100°C, each over a range of pressures from 24 to 120 bar. Foaming was not observed when the polymer was initially at conditions below Tg but was observed above Tg. The nucleation appeared to occur randomly leading to subsequent bubble growth from these sites, with maximum radius of 0.02–0.83 mm. Three models were applied on the foaming experimental data. Variable diffusivity and viscosity model (Model C) was applied to assess the experimental data with the WLF equation. The model shows very good agreement by using realistic parameter values. The expansion occurs by diffusion of a dissolved gas from the supersaturated polymer envelope into the bubble. [ABSTRACT FROM AUTHOR]

The article presents parameters for obtaining a carbon dioxide extract from the subterranean part of Eryngium planum that contains a valuable set of organic substances and has a certain antimicrobial effect. Methods. Raw materials were collected in the Almaty region (Republic of Kazakhstan). The CO2 extract of Eryngium planum herbs was obtained under subcritical conditions. A gas chromatograph with a mass spectrometric detector was used to determine the compositional breakdown of the extract. Antimicrobial activity was determined by two methods: the micromethod of serial dilutions and the disk-diffusion method. Three microbial test strains were used: Staphylococcus aureus ATCC 6538-P, Escherichia coli ATCC 8739, and Candida albicans ATCC 10231. Results. To extract biologically active substances from the subterranean part of Eryngium planum L., we have chosen carbon dioxide extraction technology, a technology for processing carbon dioxide (CO2) raw materials, which allows us to extract various substances in high concentrations. Carbon dioxide extraction technology is an effective and environmentally safe way to isolate various biologically active substances contained in medicinal plant raw materials. In the composition of the CO2 extract of Eryngium planum L. 43 components were identified, the main of which are α-linolenic acid, 8.30%; myristic acid, 6.40%; caryophyllene, 6.92%; spatulous, 6.62%; and other main identified compounds and their percentage. Conclusions. The study showed that the CO2 extract of Eryngium planum L. contains biologically active compounds that have a pronounced antimicrobial effect against clinically significant microorganisms, such as Escherichia coli, Staphylococcus aureus, and Candida albicans. [ABSTRACT FROM AUTHOR]

It is not the first time in human history, nor will it be the last for that matter, that a collective problem calls for a collective response. Climate change fueled by greenhouse emissions affects humankind alike. Despite the disagreement among policymakers and scientists on the severity of the issue, the truth is that the problem remains. A broad look at different technologies being used today in different fields has led to the idea of bringing them together in an attempt to offer a viable solution to reducing anthropogenic CO2. The following paper describes how the nanotechnologies, available or soon to be available, would make CO2 capture, cache, and conversion (coined the three Cs) a valid way for achieving a more sustainable energy society. Authors also set out to highlight with this work how knowledge transfer is instrumental in the development of technology and how methodical assessment of crossovers can expedite research when time plays against us. [ABSTRACT FROM AUTHOR]

Major shale gas exploration and development fields are located in the Sichuan basin. It requires huge water sources for shale gas fracking, but the well sites are mostly in the hills, which limits the industrialization of shale gas development. CO2 foam fluids can meet the requirements of fracking fluids and relieve water stress. It analyzed the feasibility of CO2 foaming fracturing for shale gas formation fracturing, proposed a design philosophy for CO2 foaming fracturing, and optimized fracturing parameters such as foam mass, proppant concentration, friction, and discharge rate. The flowchart of CO2 foam fracturing was established in, where the fracture morphology and propagation behavior of CO2 foam fracturing were obtained from numerical simulations comparable to the hydraulic fracture generated by conventional hydraulic fracturing. The CO2 foaming fracturing technique can provide a discharge rate of 6.0 m3/min and fluid volume and captures the volume effect of the current stimulated reservoir, which needs to be improved. It can be considered an initial survey of CO2 foam fracturing available in the Sichuan Basin shale formation, which may provide new methods and clues for stimulation. [ABSTRACT FROM AUTHOR]

The fast industrial revolution all over the world has increased emission of carbon dioxide (CO2), which has badly affected the atmosphere. Main sources of CO2 emission include vehicles and factories, which use oil, gas, and coal. Similarly, due to the increased mobility of automobiles, CO2 emission increases day-by-day. Roughly, 40% of the world's total CO2 emission is due to the use of personal cars on busy and congested roads, which burn more fuel. In addition to this, the unavailability of parking in all parts of the cities and the use of conventional methods for searching parking areas have added more to this problem. To solve the problem of reducing CO2 emission, a novel cloud-based smart parking methodology is proposed. This methodology enables drivers to automatically search for nearest parking(s) and recommend the most preferred ones that have empty lots. For determining preferences, the methodology uses the analytical hierarchy process (AHP) of multicriteria decision-making methods. For aggregating the decisions, the weighted sum model (WSM) is adopted. The methods of sorting, multilevel multifeatures filtering, exploratory data analysis (EDA), and weighted sum model (WSM) are used for ranking parking areas and recommending top-k parking to the drivers for parking their cars. To implement the methodology, a scenario comprising cars, smart parkings are considered. To use EDA, a freely available dataset "2020testcar-2020-03-03" is used for the estimation of CO2 emitted by cars. For evaluation purpose, the results obtained are compared with the results of traditional approach. The comparison results show that the proposed methodology outperforms the traditional approach. [ABSTRACT FROM AUTHOR]

This paper presents the numerical investigation and optimization of the operating parameters of the in situ generated CO2 Huff-n-Puff method with compound surfactant on the performance of enhanced oil recovery. First, we conducted experiments of in situ generated CO2 and surfactant flooding. Next, we constructed a single-well radial 3D numerical model using a thermal recovery chemical flooding simulator to simulate the process of CO2 Huff-n-Puff. The activation energy and reaction enthalpy were calculated based on the reaction kinetics and thermodynamic models. The interpolation parameters were determined through history matching a series of surfactant core flooding results with the simulation model. The effect of compound surfactant on the Huff-n-Puff CO2 process was demonstrated via a series of sensitivity studies to quantify the effects of a number of operation parameters including the injection volume and mole concentration of the reagent, the injection rate, the well shut-in time, and the oil withdrawal rate. Based on the daily production rate during the period of Huff-n-Puff, a desirable agreement was shown between the field applications and simulated results. [ABSTRACT FROM AUTHOR]

The standard-of-care guidelines published by the American Society of Anesthesiologists (ASA) recommend monitoring of pulse oximetry, blood pressure, heart rate, and end tidal CO2 during the use of anesthesia and sedation. This information can help to identify adverse events that may occur during procedures. However, these parameters are not specific to the effects of anesthetics or sedatives, and therefore they offer little, to no, real time information regarding the effects of those agents and do not give the clinician the lead-time necessary to prevent patient "awareness." Since no "gold-standard" method is available to continuously, reliably, and effectively monitor the effects of sedatives and anesthetics, such a method is greatly needed. Investigation of the use of functional near-infrared spectroscopy (fNIRS) as a method for anesthesia or sedation monitoring and for the assessment of the effects of various anesthetic drugs on cerebral oxygenation has started to be conducted. The objective of this paper is to provide a thorough review of the currently available published scientific studies regarding the use of fNIRS in the fields of anesthesia and sedation monitoring, comment on their findings, and discuss the future work required for the translation of this technology to the clinical setting. [ABSTRACT FROM AUTHOR]

The rapid development of economic society causes people to increase the energy demand, produce more and more carbon dioxide, environmental pollution is becoming more and more serious, to solve the problem of carbon peak is imminent. Under the same and complete evaluation system, the carbon emission performance varies slightly according to different R&D directions of new energy enterprises. Therefore, it is particularly important to select evaluation indicators. In fact, each enterprise has different efforts to control carbon emissions. While studying the performance of carbon emissions, the direct and indirect impacts of carbon dioxide produced by each enterprise in the process of production on the ecological environment should be considered. In order to guarantee systematic and scientific outcomes, carbon emissions performance evaluation indicator system for new energy enterprises is constructed. With new energy enterprises as examples, based on the construction of carbon emissions performance evaluation indicator system of new energy enterprises, orthogonal projection method is used to carry out an empirical analysis of the dynamic evaluation of carbon emissions performance of thirty new energy enterprises. Through the questionnaire survey of thirty new energy enterprises, the indicator weight of carbon emission performance evaluation of new energy enterprises was determined, and the carbon emission performance of new energy enterprises was analyzed. The results will reflect the actual situation of China's new energy enterprises, and provide the data support and references for future research on carbon emission control by the country and enterprises. [ABSTRACT FROM AUTHOR]

Based on the Soave–Redlich–Kwong equation of state, empirical correlations for the K -values of N 2 , CO 2 , H 2 S , C 1 , and C 2 are proposed. Complementarily, the binary interaction coefficients involving the plus fraction, C 7 + , were optimized by fitting into 131 experimental data from the literature. The criterion to select the form of the empirical correlations was based on the identification of the major dependencies of the equilibrium constants on the system variables (e.g., pressure, temperature, and composition). For most of the experimental data, the saturation pressure calculated via the empirical correlations is in excellent agreement with those reported from the laboratory. The empirical correlations cover a variety of temperatures (128–314°F), pressures (313–6880 psi), and compositions (N2: 0.0–1.67%; CO2: 0.0–9.11%; H2S: 0.0–3.68%; C1: 5.63–74.18%; C2: 0.84–12.45%; C7+: 10.72–83.2%). The proposed correlations are useful for rapid vapor-liquid equilibrium calculations during the compositional modeling of petroleum reservoirs. [ABSTRACT FROM AUTHOR]

Melanic pigmentation results from melanin produced by the melanocytes present in the basal layer of the oral epithelium. One of the most common causes of oral pigmentation is smoker melanosis, a condition associated with the melanocyte stimulation caused by cigarette smoke. This paper aims to illustrate the use of a carbon dioxide laser in the removal of the gingival melanic pigmentation for aesthetic reasons in a 27-year-old female patient with history of a smoking habit. The carbon dioxide laser vaporisation was performed on the gingival mucosa with effective and quick results and without any complications or significant symptoms after the treatment. We conclude that a carbon dioxide laser could be a useful, effective, and safe instrument to treat the aesthetic complications caused by oral smoker melanosis. [ABSTRACT FROM AUTHOR]

This paper reports the preparation of wide gap p-type hydrogenated microcrystalline silicon oxide (p-μc-SiO:H) films using a 40 MHz very high frequency plasma enhanced chemical vapor deposition technique. The reported work focused on the effects of the CO2/SiH4 ratio on the properties of p-μc-SiO:H films and the effectiveness of the films as an emitter layer of crystalline silicon heterojunction (c-Si-HJ) solar cells. A p-μc-SiO:H film with a wide optical band gap (E04), 2.1 eV, can be obtained by increasing the CO2/SiH4 ratio; however, the tradeoff between E04 and dark conductivity must be considered. The CO2/SiH4 ratio of the p-μc-SiO:H emitter layer also significantly affects the performance of the solar cells. Compared to the cell using p-μc-Si:H (CO2/SiH4 = 0), the cell with the p-μc-SiO:H emitter layer performs more efficiently. We have achieved the highest efficiency of 18.3% with an open-circuit voltage (Voc) of 692 mV from the cell using the p-μc-SiO:H layer. The enhancement in the Voc and the efficiency of the solar cells verified the potential of the p-μc-SiO:H films for use as the emitter layer in c-Si-HJ solar cells. [ABSTRACT FROM AUTHOR]

This paper explores the dynamics of respiratory gases interactions which are accompanied by the loss of water through an insect's spiracle. Here we investigate and analyze this interaction by deriving a system of ordinary differential equations for oxygen, carbon dioxide, and water vapor. The analysis is carried out in continuous time. The purpose of the research is to determine bounds for the gas volumes and to discuss the complexity and stability of the equilibria. Numerical simulations also demonstrate the dynamics of our model utilizing the new conditions for stability and instability. [ABSTRACT FROM AUTHOR]

Caffeine is considered a widely consumed natural and legal psychoactive stimulant with several effects on the body. The present study attempted to investigate the effects of caffeine consumed before and after a physical exercise on cardiovascular and cardiorespiratory functions in healthy adults. 36 healthy adult males were recruited and randomly allocated to one of the three (3) groups: group I (exercise without caffeine consumption), group II (caffeine beverage intake before exercise), and group III (caffeine beverage intake immediately after exercise). The heart rate (HR), QTc interval, blood pressure (BP), respiratory rate (RR), oxygen consumption (VO₂), and carbon dioxide emission (VCO₂) were measured at 0, 5, 10, and 15 min after the exercise. We observed a significant difference in all measured outcomes during the different recovery times in all the groups (p < 0.05). HR, RR, SBP, VO2, and VCO2 gradually decreased with time, DBP contrarily increased with time, and the QTc showed an irregular pattern. We can affirm that ingestion of caffeine before and after moderate aerobic exercise slows down the parasympathetic stimulation, heart rate recovery, and the recovery of HR and QTc with no major effects on BP, RR, VO₂, and VCO₂ in healthy adult men. [ABSTRACT FROM AUTHOR]

This paper indicates the possibility of application of imidazolium ionic liquids immobilized in polymeric supports--supported ionic liquid membranes--in CO2 separation from gaseous streams (e.g., biogas). Imidazolium salts containing alkyl fluoride anions, bis(trifluoromethylsulfonyl)imide and trifluoromethanesulfonate, selectively separating CO2 were used. The permeability of CO2 through membranes was investigated under gas pressure of 30 kPa and temperature range 283-298 K. Permeability values occurred to be higher for ionic liquids containing bis(trifluoromethylsulfonyl)imide anion. Moreover, CO2 permeability exhibited an increase with increasing temperature for all investigated systems. Stability of supported ionic liquid membranes was studied. In total, polypropylene membrane revealed the best properties, mechanical stability and observed wettability of this support were better than for polyamide and polyvinylidene fluoride ones. Polyethersulfone supports showed similar contact angles; however, its mechanical stability was significantly lower. Obtained results allowed to evaluate the effectiveness of separation process using selected ILs and supports. [ABSTRACT FROM AUTHOR]