scholarly journals Diffusion of CO2 in Magnesite under High Pressure and High Temperature from Molecular Dynamics Simulations

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Lei Liu ◽  
Longxing Yang ◽  
Chunqiang Zhuang ◽  
Guangshu Yang ◽  
Li Yi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Carbon Cycle ◽  
Anisotropic Diffusion ◽  
Global Climate ◽  
Extreme Condition ◽  
Global Climate Changes ◽  
Co2 Diffusion ◽  
The Earth ◽  
Earth Condition ◽  
Dynamics Simulations

CO2 transports in the Earth’s interior play a crucial role in understanding the deep carbon cycle and the global climate changes. Currently, CO2 transports inside of the Earth under extreme condition of pressure and temperature have not been understood well. In this study, the molecular dynamics (MD) calculations were performed to study CO2 transports under different CO2 pressures in slit-like magnesite pores with different pore sizes at 350~2500 K and 3~50 GPa are presented. Diffusion of CO2 in magnesite was improved as the temperature increases but showed the different features as a function of pressure. The diffusion coefficients of CO2 in magnesite were found in the range of 9 × 10 − 12   m 2   s − 1 ~ 28000 × 10 − 12   m 2   s − 1 . Magnesite with the pore size of 20~25 Å corresponds to the highest transports. Anisotropic diffusion of CO2 in magnesite may help to understand the inhomogeneous distribution of carbon in the upper mantle. The time of CO2 diffusion from the mantle to Earth surface was estimated to be around several tens of Ma and has an important effect on deep carbon cycle. The simulation of CO2 transports based on the Earth condition provides new insights to revealing the deep carbon cycle in the Earth’s interiors.

Introduction

2004 ◽  
Author(s):  
Robert A. Berner
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Global Climate ◽  
Geological Time ◽  
Short Term ◽  
Quaternary Period ◽  
Geological Time Scale ◽  
The Earth

The cycle of carbon is essential to the maintenance of life, to climate, and to the composition of the atmosphere and oceans. What is normally thought of as the “carbon cycle” is the transfer of carbon between the atmosphere, the oceans, and life. This is not the subject of interest of this book. To understand this apparently confusing statement, it is necessary to separate the carbon cycle into two cycles: the short-term cycle and the long-term cycle. The “carbon cycle,” as most people understand it, is represented in figure 1.1. Carbon dioxide is taken up via photosynthesis by green plants on the continents or phytoplankton in the ocean. On land carbon is transferred to soils by the dropping of leaves, root growth, and respiration, the death of plants, and the development of soil biota. Land herbivores eat the plants, and carnivores eat the herbivores. In the oceans the phytoplankton are eaten by zooplankton that are in turn eaten by larger and larger organisms. The plants, plankton, and animals respire CO2. Upon death the plants and animals are decomposed by microorganisms with the ultimate production of CO2. Carbon dioxide is exchanged between the oceans and atmosphere, and dissolved organic matter is carried in solution by rivers from soils to the sea. This all constitutes the shortterm carbon cycle. The word “short-term” is used because the characteristic times for transferring carbon between reservoirs range from days to tens of thousands of years. Because the earth is more than four billion years old, this is short on a geological time scale. As the short-term cycle proceeds, concentrations of the two principal atmospheric gases, CO2 and CH4, can change as a result of perturbations of the cycle. Because these two are both greenhouse gases—in other words, they adsorb outgoing infrared radiation from the earth surface—changes in their concentrations can involve global warming and cooling over centuries and many millennia. Such changes have accompanied global climate change over the Quaternary period (past 2 million years), although other factors, such as variations in the receipt of solar radiation due to changes in characteristics of the earth’s orbit, have also contributed to climate change.

scholarly journals Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing

2017 ◽  
Author(s):  
Steven J. Lade ◽  
Jonathan F. Donges ◽  
Ingo Fetzer ◽  
John M. Anderies ◽  
Christian Beer ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Model Test ◽  
Global Climate ◽  
Earth System ◽  
Planetary Boundaries ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
The Earth ◽  
Analytical Expressions ◽  
Earth System Models

Abstract. Changes to climate-carbon cycle feedbacks may significantly affect the Earth System’s response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon-cycle feedbacks and the operation of the carbon cycle. We use our results to analytically study the relative strengths of different climate-carbon cycle feedbacks and how they may change in the future, as well as to compare different feedback formalisms. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the Planetary Boundaries, that are currently too uncertain to be included in complex ESMs.

scholarly journals Glycine in aerosol water droplets: a critical assessment of Köhler theory by predicting surface tension from molecular dynamics simulations

2011 ◽  
Vol 11 (2) ◽  
pp. 519-527 ◽  
Author(s):  
X. Li ◽  
T. Hede ◽  
Y. Tu ◽  
C. Leck ◽  
H. Ågren
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Molecular Dynamics Simulations ◽  
Global Climate ◽  
Pure Water ◽  
Model Systems ◽  
Water Droplets ◽  
Cloud Droplets ◽  
Kohler Theory ◽  
Dynamics Simulations

Abstract. Aerosol particles in the atmosphere are important participants in the formation of cloud droplets and have significant impact on cloud albedo and global climate. According to the Köhler theory which describes the nucleation and the equilibrium growth of cloud droplets, the surface tension of an aerosol droplet is one of the most important factors that determine the critical supersaturation of droplet activation. In this paper, with specific interest to remote marine aerosol, we predict the surface tension of aerosol droplets by performing molecular dynamics simulations on two model systems, the pure water droplets and glycine in water droplets. The curvature dependence of the surface tension is interpolated by a quadratic polynomial over the nano-sized droplets and the limiting case of a planar interface, so that the so-called Aitken mode particles which are critical for droplet formation could be covered and the Köhler equation could be improved by incorporating surface tension corrections.

scholarly journals Discussões sobre as mudanças climáticas globais: os alarmistas, os céticos e os modelos de previsão do clima

GeoTextos ◽  
2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Francisco Ronnieplex De Moura Cruz ◽  
Letícia Andrade da Silva ◽  
Elisiene De Macêdo Pereira ◽  
Rebecca Luna Lucena
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Climate Changes ◽  
Climate Models ◽  
Global Climate ◽  
Intergovernmental Panel ◽  
Global Climate Changes ◽  
The Earth ◽  
Scientific Papers ◽  
Forecast Models

Este ensaio traz à tona questões intrigantes e dúvidas que permeiam as pesquisas voltadas às mudanças climáticas globais, enfatizando as discordâncias existentes entre as distintas correntes de cientistas e os prognósticos elaborados pelos modelos de previsão do clima. Para tanto, tomou-se por base as teorias propagadas por alarmistas e céticos, bem como o prognóstico do Painel Intergovernamental sobre as Mudanças Climáticas (IPCC) de 2007. O ensaio se baseou na análise de livros, relatórios técnicos e artigos científicos, além da interpretação dos gráficos contidos nos mesmos. Os resultados mostraram que sempre houve variação na temperatura da atmosfera, mesmo antes do surgimento do homem e em níveis bem mais elevados do que os atuais. Contudo, alarmistas e céticos concordam que a Terra passou por um aquecimento de cerca de 0,6ºC no século XX, havendo divergência no que diz respeito às causas desse aquecimento, suas consequências, e se ele ainda está ocorrendo. Entretanto, um aspecto que põe em xeque a confiabilidade de ambas as correntes diz respeito ao problema da previsão, pois são muitos os fatores e elementos envolvidos na complexidade do sistema climático, tornando, assim, previsões climáticas exatas praticamente impossíveis, e deixando o debate, até o momento, no campo das suposições. Abstract DISCUSSIONS ABOUT GLOBAL CLIMATE CHANGES: THE ALARMISTS, THE SKEPTICS AND CLIMATE FORECAST MODELS This paper aims to discuss difficult questions and doubts about researches regarding global climate change, showing discordances about what different scientific groups and the forecasts elaborated by forecasting climate models. Therefore, we take for basis the theories formulated by the two scientific groups: the alarmists and skeptics, and the prognostic showed by the Intergovernmental Panel of Climate Change (IPCC), 2007. This work was based in a research of books, technical documents and scientific papers, and the interpretation of graphs and data within these works. The results showed that oscillating temperatures always existed in the Earth’s atmosphere before human existence and the oscillation was larger than today. However, alarmists and skeptics believe that the earth atmosphere’s temperature elevated by approximated 0.6º C in the XX century, but there is a big divergence about the causes that rise and the consequences. Finally, an issue that questions the reliability of both groups, concerns the problem of forecast mainly because there are many factors and elements involved in the complexity of climate system thus making accurate climate predictions virtually impossible and leaving the debate so far, in the field of assumptions.

scholarly journals Glycine in aerosol water droplets: a critical assessment of Köhler theory by predicting surface tension from molecular dynamics simulations

2010 ◽  
Vol 10 (10) ◽  
pp. 23169-23196 ◽  
Author(s):  
X. Li ◽  
T. Hede ◽  
Y. Tu ◽  
C. Leck ◽  
H. Ågren
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Molecular Dynamics Simulations ◽  
Global Climate ◽  
Pure Water ◽  
Model Systems ◽  
Water Droplets ◽  
Cloud Droplets ◽  
Kohler Theory ◽  
Dynamics Simulations

Abstract. Aerosol particles in the atmosphere are important participants in the formation of cloud droplets and have significant impact on cloud albedo and global climate. According to the Köhler theory which describes the nucleation and the equilibrium growth of cloud droplets, the surface tension of an aerosol droplet is one of the most important factors that determine the critical supersaturation of droplet activation. In this paper, with specific interest to remote marine aerosol, we predict the surface tension of aerosol droplets by performing molecular dynamics simulations on two model systems; the pure water droplets and glycine in water droplets. The curvature dependence of the surface tension is interpolated by a quadratic polynomial over the nano-sized droplets and the limiting case of a planar interface, so that the so-called Aitken mode particles which are critical for droplet formation could be covered and the Köhler equation could be improved by incorporating surface tension corrections.

Novel Defects and Anisotropic Vacancy Diffusion on Reconstructed Surfaces

1999 ◽  
Vol 585 ◽  
Author(s):  
O. Rodríguez De La Fuente ◽  
M. A. González ◽  
J. M. Rojo
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Anisotropic Diffusion ◽  
Previous Investigation ◽  
Diffusion Mechanism ◽  
Vacancy Diffusion ◽  
Reconstructed Surfaces ◽  
Intermediate States ◽  
Topmost Layer ◽  
Dynamics Simulations

AbstractSTM and molecular dynamics simulations are used to study Au(001) 5×25 reconstructed surfaces after Ar+ bombardment at 600 eV and ion doses from 0.05 to 1 ML+. Surface 2D dislocation dipoles, identified as such in a previous investigation, are shown to have dislocation properties and to be formed by anisotropic diffusion of surface vacancies along the ridges of the reconstructed topmost layer. A new vacancy diffusion mechanism involving intermediate states with de-localized vacancies is identified. Increasing ion fluences is shown to lead to the formation of vacancy islands that are nucleated at the dislocation dipoles.

Carbon sequestration and its impact on rice farming economic value: The quasi-experiment

2021 ◽  
pp. 1677-1688
Author(s):  
Nandang Najmulmunir ◽  
Nana Danapriatna ◽  
Dwi Purwoko ◽  
Ujang Maman
Keyword(s):  
Carbon Dioxide ◽  
Global Climate ◽  
Economic Value ◽  
Soil Conditions ◽  
Technology System ◽  
Global Climate Changes ◽  
The Earth ◽  
Cultivation Technology ◽  
Aerobic Soil ◽  
Quasi Experiment

The increasing level of the number of carbon dioxide will raise temperature on the earth and causes global climate changes. Paris agreement has responded global warming by doing mitigation, and Indonesian Government has ratified the suggestion. This research aims to determine the rice cultivation technology system which effectively could absorb the carbon dioxide into the form of biomass and C-organic in the earth. Applying the quasi-experiment by three types of technological systems – and it was conducted in farming area of Sukakarya District, Bekasi Regency, Indonesia – the research proved the T2 (IPAT-TS planting system) – in which it applies a minimum spacing of 30 cm × 30 cm and a maximum of 50 cm × 50 cm, in aerobic soil conditions – yields the highest number of biomass straw, C-Organic, and harvest dry grain and economically gives the highest profit margin. Therefore, the research recommends the adoption of T2 as mass common farming practice especially in entisolic soil types.

ACCELERATION OF BIOMOLECULAR DYNAMICS SIMULATIONS ON THE EARTH SIMULATOR

2008 ◽  
Vol 05 (02) ◽  
pp. 319-327
Author(s):  
MASAAKI SUZUKI ◽  
HIROSHI OKUDA
Keyword(s):  
Molecular Dynamics ◽  
Parallel Programming ◽  
Tertiary Structure ◽  
Replica Exchange ◽  
Programming Approach ◽  
Parallel Efficiency ◽  
Replica Exchange Molecular Dynamics ◽  
The Earth ◽  
Biomolecular Dynamics ◽  
Dynamics Simulations

Replica exchange molecular dynamics (REMD) code has been developed for predicting protein tertiary structure and optimized assuming that simulations are performed on the Earth Simulator. A new parallel programming approach using an MPI/OpenMP model with a three-level hierarchy was developed to circumvent the problems of overhead inherent in the MPI model and shown to achieve an 88% parallel efficiency using a 256-node REMD simulation on the Earth Simulator with this model.

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