scholarly journals Effect of Graphene Nanoplatelet on the Carbonation Depth of Concrete under Changing Climate Conditions

2021 ◽  
Vol 11 (19) ◽  
pp. 9265
Author(s):  
Yingzi Zhang ◽  
Yanze Wang ◽  
Mingqian Yang ◽  
Huatao Wang ◽  
Guofang Chen ◽  
...  
Keyword(s):  
Control Sample ◽  
Co2 Concentration ◽  
Favorable Effect ◽  
Carbonation Depth ◽  
Graphene Nanoplatelet ◽  
Carbonation Reaction ◽  
Climate Conditions ◽  
Ordinary Concrete ◽  
Changing Climate ◽  
Carbon Dioxide Co2

Climate change has been unprecedented in the past decades or even thousands of years, which has had an adverse impact on the mechanical properties of concrete structures. Many researchers have begun to study new concrete materials. Graphene nanoplatelet (GNP) is an attractive nanomaterial that can change the crystal structure of concrete and improve durability. The aim of the present study was to investigate the effect of GNP (0.05%wt) on the carbonation depth of concrete under simulated changing climate conditions (varying temperature, relative humidity, and carbon dioxide (CO2) concentration), and compare it with ordinary concrete. When the concentration of CO2 is variable, the carbonation depth of graphene concrete is 10% to 20% lower than that of ordinary concrete. When the temperature is lower than 33 °C, the carbonation depth of graphene concrete is less than that of the control sample; however, above 33 °C, the thermal conductivity of GNP increases the carbonation reaction rate of concrete. When the humidity is a variable, the carbonation depth of graphene concrete is less than 15% to 30% of ordinary concrete, and when the humidity is higher than 78%, the difference in the carbonation depth between the ordinary concrete and the graphene concrete decreases gradually. The overall results indicated that GNP has a favorable effect on anti-carbonation performance under changing climate conditions.

scholarly journals Computational Studies of Two-Phase Cement/CO2/Brine Interaction in Wellbore Environments

SPE Journal ◽  
2011 ◽  
Vol 16 (04) ◽  
pp. 940-948 ◽  
Author(s):  
J. William Carey ◽  
Peter C. Lichtner
Keyword(s):  
Oil Recovery ◽  
Co2 Concentration ◽  
Poor Quality ◽  
Geologic Sequestration ◽  
Two Phase ◽  
Carbonation Reaction ◽  
Wellbore Integrity ◽  
Reaction Fronts ◽  
Flow Through ◽  
Carbon Dioxide Co2

Summary Wellbore integrity is essential to ensuring long-term isolation of buoyant supercritical carbon dioxide (CO2) during geologic sequestration of CO2. In this paper, we summarize recent progress in numerical simulations of cement/brine/CO2 interactions with respect to migration of CO2 outside of casing. Using typical values for the hydrologic properties of cement, caprock (shale), and reservoir materials, we show that the capillary properties of good-quality cement will prevent flow of CO2 into and through cement. Rather, CO2, if present, is likely to be confined to the casing/cement or cement/formation interface. CO2 does react with the cement by diffusion from the interface into the cement, in which case it produces distinct carbonation fronts within the cement. This is consistent with observations of cement performance at the CO2-enhanced-oil-recovery Scurry Area Canyon Reef Operators Committee (SACROC) unit in west Texas (Carey et al. 2007). For poor-quality cement, flow through cement may occur and would produce a pattern of uniform carbonation without reaction fronts. We also consider an alternative explanation for cement carbonation reactions as caused by CO2 derived from caprock. We show that carbonation reactions in cement are limited to surficial reactions when CO2 pressure is low (< 10 bar), as might be expected in many caprock environments. For the case of caprock overlying natural CO2 reservoirs for millions of years, we consider the Scherer and Huet (2009) hypothesis of diffusive steady state between CO2 in the reservoir and in the caprock. We find that, in this case, the aqueous CO2 concentration would differ little from that in the reservoir and would be expected to produce carbonation reaction fronts in cements that are relatively uniform as a function of depth.

scholarly journals The Synergistic Effect of PM2.5 and CO2 Concentrations on Occupant Satisfaction and Work Productivity in a Meeting Room

2021 ◽  
Vol 18 (8) ◽  
pp. 4109
Author(s):  
Jindong Wu ◽  
Jiantao Weng ◽  
Bing Xia ◽  
Yujie Zhao ◽  
Qiuji Song
Keyword(s):  
Air Quality ◽  
Synergistic Effect ◽  
Work Productivity ◽  
Co2 Concentration ◽  
Human Beings ◽  
Meeting Room ◽  
Negative Effect ◽  
Carbon Dioxide Co2 ◽  
Occupant Satisfaction ◽  
Pm2.5 Concentration

High indoor air quality is crucial for the health of human beings. The purpose of this work is to analyze the synergistic effect of particulate matter 2.5 (PM2.5) and carbon dioxide (CO2) concentration on occupant satisfaction and work productivity. This study carried out a real-scale experiments in a meeting room with exposures of up to one hour. Indoor environment parameters, including air temperature, relative humidity, illuminance, and noise level, were controlled at a reasonable level. Twenty-nine young participants were participated in the experiments. Four mental tasks were conducted to quantitatively evaluate the work productivity of occupants and a questionnaire was used to access participants’ satisfaction. The Spearman correlation analysis and two-way analysis of variance were applied. It was found that the overall performance declined by 1% for every 10 μg/m3 increase in PM2.5 concentration. Moreover, for every 10% increase in dissatisfaction with air quality, productivity performance decreased by 1.1% or more. It should be noted that a high CO2 concentration (800 ppm) has a stronger negative effect on occupant satisfaction towards air quality than PM2.5 concentration in a non-ventilated room. In order to obtain optimal occupant satisfaction and work productivity, low concentrations of PM2.5 (<50 μg/m3) and CO2 (<700 ppm) are recommended.

scholarly journals The Exploitation of Local Vitis vinifera L. Biodiversity as a Valuable Tool to Cope with Climate Change Maintaining Berry Quality

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
María Carmen Antolín ◽  
María Toledo ◽  
Inmaculada Pascual ◽  
Juan José Irigoyen ◽  
Nieves Goicoechea
Keyword(s):  
Climate Change ◽  
Fruit Quality ◽  
Atmospheric Carbon Dioxide ◽  
Antioxidant Properties ◽  
Co2 Concentration ◽  
Soluble Solids ◽  
Vitis Vinifera L ◽  
Grape Quality ◽  
Berry Quality ◽  
Carbon Dioxide Co2

(1) Background: The associated increase in global mean surface temperature together with raised atmospheric carbon dioxide (CO2) concentration is exerting a profound influence on grapevine development (phenology) and grape quality. The exploitation of the local genetic diversity based on the recovery of ancient varieties has been proposed as an interesting option to cope with climate change and maintaining grape quality. Therefore, this research aimed to characterize the potential fruit quality of genotypes from seven local old grapevine varieties grown under climate change conditions. (2) Methods: The study was carried out on fruit-bearing cuttings (one cluster per plant) that were grown in pots in temperature gradient greenhouses (TGG). Two treatments were applied from fruit set to maturity: (1) ambient CO2 (400 ppm) and temperature (T) (ACAT) and (2) elevated CO2 (700 ppm) and temperature (T + 4 °C) (ECET). (3) Results: Results showed that some of the old genotypes tested remained quite stable during the climate change conditions in terms of fruit quality (mainly, total soluble solids and phenolic content) and of must antioxidant properties. (4) Conclusion: This research underlines the usefulness of exploiting local grapevine diversity to cope with climate change successfully, although further studies under field conditions and with whole plants are needed before extrapolating the results to the vineyard.

scholarly journals Potential shift from a carbon sink to a source in Amazonian peatlands under a changing climate

2018 ◽  
Vol 115 (49) ◽  
pp. 12407-12412 ◽  
Author(s):  
Sirui Wang ◽  
Qianlai Zhuang ◽  
Outi Lähteenoja ◽  
Frederick C. Draper ◽  
Hinsby Cadillo-Quiroz
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Accumulation Rate ◽  
Foreland Basin ◽  
Carbon Accumulation ◽  
Climate Conditions ◽  
Changing Climate ◽  
Soil Carbon Density ◽  
Increasing Precipitation ◽  
Aerobic And Anaerobic

Amazonian peatlands store a large amount of soil organic carbon (SOC), and its fate under a future changing climate is unknown. Here, we use a process-based peatland biogeochemistry model to quantify the carbon accumulation for peatland and nonpeatland ecosystems in the Pastaza-Marañon foreland basin (PMFB) in the Peruvian Amazon from 12,000 y before present to AD 2100. Model simulations indicate that warming accelerates peat SOC loss, while increasing precipitation accelerates peat SOC accumulation at millennial time scales. The uncertain parameters and spatial variation of climate are significant sources of uncertainty to modeled peat carbon accumulation. Under warmer and presumably wetter conditions over the 21st century, SOC accumulation rate in the PMFB slows down to 7.9 (4.3–12.2) g⋅C⋅m−2⋅y−1 from the current rate of 16.1 (9.1–23.7) g⋅C⋅m−2⋅y−1, and the region may turn into a carbon source to the atmosphere at −53.3 (−66.8 to −41.2) g⋅C⋅m−2⋅y−1 (negative indicates source), depending on the level of warming. Peatland ecosystems show a higher vulnerability than nonpeatland ecosystems, as indicated by the ratio of their soil carbon density changes (ranging from 3.9 to 5.8). This is primarily due to larger peatlands carbon stocks and more dramatic responses of their aerobic and anaerobic decompositions in comparison with nonpeatland ecosystems under future climate conditions. Peatland and nonpeatland soils in the PMFB may lose up to 0.4 (0.32–0.52) Pg⋅C by AD 2100 with the largest loss from palm swamp. The carbon-dense Amazonian peatland may switch from a current carbon sink into a source in the 21st century.

scholarly journals Effects of Environmental Factors on Concrete Carbonation Depth and Compressive Strength

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2167 ◽  
Author(s):  
Ying Chen ◽  
Peng Liu ◽  
Zhiwu Yu
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Relative Humidity ◽  
Co2 Concentration ◽  
Crystal Structure Analysis ◽  
Hydration Products ◽  
Carbonation Depth ◽  
Concrete Carbonation ◽  
Before And After ◽  
Compressive Strength Of Concrete

The influence of temperature, CO2 concentration and relative humidity on the carbonation depth and compressive strength of concrete was investigated. Meanwhile, phase composition, types of hydration products and microstructure characteristics of samples before and after the carbonation were analyzed by XRD and ESEM. Research results demonstrate that temperature, CO2 concentration and relative humidity influence the carbonation depth and compressive strength of concrete significantly. There is a linear relationship between temperature and carbonation depth, as well as the compressive strength of concrete. CO2 concentration and relative humidity present a power function and a polynomial function with carbonation depth of concrete, respectively. The concrete carbonation depth increases with the increase of relative humidity and reaches the maximum value when the relative humidity is 70%. Significant differences of phase composition, hydration products and microstructure are observed before and after the carbonation. Carbonization products of samples are different with changes of temperatures (10 °C, 20 °C and 30 °C). The result of crystal structure analysis indicates that the carbonation products are mainly polyhedral spherical vaterite and aragonite.

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