scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2020 ◽  
Vol 2(29)2020 (2(29)) ◽  
pp. 79-88
Author(s):  
Yu. V. Khokha ◽  
◽  
M. B. Yakovenko ◽  
O. V. Lubchak ◽  
◽  
...  
Keyword(s):  
System Modeling ◽  
Thermodynamic System ◽  
Entropy Method ◽  
Heat Fluxes ◽  
Practical Significance ◽  
Lithostatic Pressure ◽  
Type Ii ◽  
Hydrocarbon Gases ◽  
Entropy Maximization ◽  
Gas System

Purpose. Our research main purpose is to demonstrate the use of entropy maximization method for calculating the geochemical system composition, which consist of solid and gaseous organic substances. Changing the geodynamic situation is the driving force of elements redistribution between compounds in such systems. According to thermodynamic apparatus the main factors influencing this redistribution are pressure, temperature and the initial number of elements. Methods. Gibbs energy minimizing, maximizing the entropy, independent chemical reactions constants, Lagrange's method of undetermined multipliers, Newton–Raphson iterative method. It is well known that the fossilized organic matter, which is mainly represented by many types of kerogen, is an irregular polymer with structure, which cannot be described definitely. To calculate the equilibrium in the kerogen/gas system and obtain reliable results, it is necessary to apply a new model, without using the model structures of kerogen. We have proposed and described in detail a method of applying the Jaynes' formalism and maximizing entropy method to calculate the change in the composition of the kerogen/gas system with geodynamic regimes changing. Software in the Excel macros form and a compiled dynamic library, written in Visual Basic language, was created for calculations. Results. To verify the reliability of the proposed method and algorithm, we calculated the composition of the geochemical system, consisting of type II kerogen, methane to pentane hydrocarbons (including isomers), carbon dioxide, water and hydrogen sulfide. The calculation result is the molar fractions of hydrocarbon components and additive groups that make up kerogen, for different depths of the earth's crust. The calculations were performed for three heat fluxes: 40, 75 and 100 mW/m2, lithostatic pressure taken in account. Scientific novelty. It is established that the geodynamic situation changing in a complex way affects the distribution of elements between gases and kerogen in a closed thermodynamic system; modeling the kerogen/gas system behavior by method of entropy maximization provides results that do not contradict to study the structure of type II kerogen at different stages of maturity; the character of changes in the concentrations of hydrocarbon gases in equilibrium with type II kerogen indicates the inconsistency of the "oil window" hypothesis with the postulates of equilibrium thermodynamics. Practical significance. The entropy maximization method can be successfully used to calculate the composition of various geochemical systems consisting of organic compounds. The method is suitable for determining chemical composition of the irregular polymers, such as kerogen, bitumen, humic, in equilibrium with organic and inorganic gases and liquids.

MSW to synthetic natural gas: System modeling and thermodynamics assessment

2016 ◽  
Vol 48 ◽  
pp. 257-264 ◽  
Author(s):  
Lin Zhu ◽  
Le Zhang ◽  
Junming Fan ◽  
Peng Jiang ◽  
Luling Li
Keyword(s):  
Natural Gas ◽  
System Modeling ◽  
Synthetic Natural Gas ◽  
Gas System ◽  
Natural Gas System

scholarly journals Clustering analysis of the distribution characteristics of unobserved economic regions in China——Based on multi-indicator panel data

2021 ◽  
Vol 275 ◽  
pp. 01072
Author(s):  
Yang Fan
Keyword(s):  
Panel Data ◽  
Clustering Analysis ◽  
Principal Component ◽  
Entropy Method ◽  
Practical Significance ◽  
Economic Governance ◽  
Factors Affecting ◽  
Use Of Resources ◽  
Economic Regions ◽  
Component Feature

The existence of unobserved economy is one of the important factors affecting GDP calculation. This paper uses the provincial panel data from 2010 to 2019 in China, and adopts the method of principal component feature extraction to carry out cluster analysis on the multi-indicator panel data. This method preserves the dynamic characteristics of the panel data, calculates the comprehensive score of each eigenvalue, and gives weight to the eigenvalue by using the entropy method, so as to optimize the clustering results representing the eight indicators of the unobserved economy. Through the analysis, it is found that the regional development of China’s unobserved economy is obviously different, and each type has different influencing factors. This result has important practical significance for different regions in China to formulate differentiated unobserved economic governance policies. This also helps to make better use of resources and develop an energy-saving economy.

Numerical Simulation of Fluid Flow and Heat Transfer Under Flow Fluctuation Condition in Horizontal Tube

2010 ◽  
Author(s):  
Yusheng Liu ◽  
Puzhen Gao ◽  
Dianchuan Xing
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Nuclear Power ◽  
Cfd Simulation ◽  
Horizontal Tube ◽  
Heat Fluxes ◽  
Practical Significance ◽  
Flow And Heat Transfer ◽  
Flow Fluctuation ◽  
Computational Fluid Dynamics Cfd

Fluctuating flow is widely presented in nuclear power plant operating procedure. When the fluctuating flow occurs in the loop, the fluid flow and heat transfer in the core will be affected, which makes the study of flow fluctuation have more practical significance. With computational fluid dynamics (CFD), characteristics of fluid flow and heat transfer are numerically simulated in a horizontal tube under periodical fluctuating flow. The influences of different factors on the fluid flow and heat transfer are analyzed. The simulation results of steady flow and heat transfer in horizontal tube agree with the traditional empirical correlations’ results, which validates the feasibility of doing this research using CFD simulation. The horizontal tube fluctuation flow and heat transfer with different flow fluctuation periods, fluctuation relative amplitudes and heat fluxes are numerically simulated. The results show that the smaller the flow fluctuation period is, the larger the flow fluctuation relative amplitude we get, and the more evident influence of flow fluctuation on fluid flow and heat transfer can be found. The larger the heat flux is, the larger amplitude of temperature fluctuation of fluid will be. What is more, there is a lag in phase between friction coefficient and velocity, which is not presented between heat transfer coefficient and velocity.

scholarly journals Research on Evaluation of Ecological Carrying Capacity of Qinghai Province Based on PSR Model

2021 ◽  
Vol 293 ◽  
pp. 01017
Author(s):  
Xiaoyong Li ◽  
Haifa Jia ◽  
Falan Zhao
Keyword(s):  
Carrying Capacity ◽  
Comprehensive Evaluation ◽  
Entropy Method ◽  
Provincial Government ◽  
Evaluation Index System ◽  
Practical Significance ◽  
Ecological Civilization ◽  
Qinghai Province ◽  
Ecological Carrying Capacity ◽  
Index Evaluation

Quantitative research and evaluation of ecological carrying capacity in Qinghai Province is in line with the requirements of the 13th five-year plan, and is of practical significance to the construction of ecological civilization in Qinghai Province. Based on the PSR model, this paper constructs the evaluation index system of ecological carrying capacity from three aspects of pressure, state ,and response, uses the entropy method to determine the index weight coefficient, and comprehensively evaluates the changing trend of ecological carrying capacity since the 12th Five Year Plan of Qinghai Province from the perspectives of economy, society, resources, and environment. The results show that: from 2011 to 2019, the comprehensive evaluation of ecological carrying capacity in Qinghai Province shows a trend of first decreasing and then increasing, the response index evaluation increases greatly, the state index evaluation shows a fluctuating growth, and the pressure index is relatively stable. Based on this, the PSR model and entropy method are typical and quantifiable, which can provide a reference for Qinghai provincial government to control the ecological environment, study ecological sustainability and delimit the ecological red line.

scholarly journals Impacts of grid resolution on surface energy fluxes simulated with an integrated surface-groundwater flow model

2015 ◽  
Vol 12 (7) ◽  
pp. 6437-6466
Author(s):  
P. Shrestha ◽  
M. Sulis ◽  
C. Simmer ◽  
S. Kollet
Keyword(s):  
Soil Moisture ◽  
Surface Energy ◽  
Groundwater Flow ◽  
Soil Temperature ◽  
System Modeling ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Grid Resolution ◽  
Energy Fluxes ◽  
Surface Energy Fluxes

Abstract. The hydrological component of the Terrestrial System Modeling Platform (TerrSysMP) which includes integrated surface-groundwater flow, was used to investigate the grid resolution dependence of simulated soil moisture, soil temperature, and surface energy fluxes over a sub-catchment of the Rur, Germany. The investigation was motivated by the recent developments of new earth system models, which include 3-D physically based groundwater models for the coupling of land–atmosphere interaction and subsurface hydrodynamics. Our findings suggest that for grid resolutions between 100 and 1000 m, the non-local controls of soil moisture are highly grid resolution dependent. Local vegetation, however, strongly modulates the scaling behavior especially for surface fluxes and soil temperature, which depends on the radiative transfer property of the canopy. This study also shows that for grid-resolutions above a few 100 m, the variation of spatial and temporal pattern of sensible and latent heat fluxes may significantly affect the resulting atmospheric mesoscale circulation and boundary layer evolution in coupled runs.

scholarly journals Equilibrium temperatures of hydrocarbon gas formation in sedimentary strata of the Western oil and gas region of Ukraine (according to thermodynamic modelling)

2019 ◽  
Vol 4 (181) ◽  
pp. 66-77
Author(s):  
Yurii KHOKHA ◽  
Myroslava YAKOVENKO ◽  
Oleksandr LYUBCHAK ◽  
Dmytro BRYK
Keyword(s):  
Oil And Gas ◽  
Equilibrium Temperature ◽  
Component Composition ◽  
Heat Fluxes ◽  
Isomeric Form ◽  
Equilibrium System ◽  
Hydrocarbon Gases ◽  
Study Region ◽  
Natural Gases ◽  
Thermodynamic Conditions

The article reviews the question of interpretation of natural gases component composition from the aspect of their evolution. The parameters available for study, which show a strong correlation with the conditions of formation, migration and accumulation of natural hydrocarbon gases, are selected. Among these parameters, the ratio of the butanes isomeric form (i-C4/n-C4) was selected for thermodynamic analysis as a dependable indicator of the kerogen degradations temperature regime. It is shown that the dependence of the i-C4/n-C4 ratio on the normalized methane content shows the trend of increasing kerogen maturity, and deviations from this trend indicate a distant migration of hydrocarbon fluid from the formation zone to the current deposit. Analysis of the residence and thermodynamic conditions of hydrocarbons in the deposits of the Western oil and gas region showed that kerogen/gas systems are in a state close to equilibrium, in terms of thermodynamics. The composition of the gas/kerogen equilibrium system in the conditions of sedimentary thickness for two heat fluxes – 75 and 100 mW/m2 was calculated by the method based on Jaynes’s formalism. Among hydrocarbons in gases, the content of isomeric forms of butane and pentane, as well as methane, ethane and propane was calculated. The results of the calculations revealed a monotonic dependence of the equilibrium temperature and depth of formation on the ratio of isobutane to n-butane. It was found that the results of thermodynamic calculations coincide with experiments on kerosene pyrolysis and correlate with studies of the composition and residence of natural gases. Equilibrium formation temperatures were determined for 59 gas, oil and gas condensate fields of the Western oil and gas region, the information on which contained data on the i-C4/n-C4 ratio. Based on the results of calculations, maps of these temperatures distribution within the region were constructed. The analysis of the maps showed the presence of two distinct temperature maxima, which are concentrated in the Boryslav-Pokuttya oil and gas region and are located at the intersection of regional faults. It has been suggested that the hydrocarbon source is significantly distant from modern deposits for the study region. The results of the calculation are compared with the data obtained using the model of fossil hydrocarbons inorganic origin.

scholarly journals Spatio-Temporal Comprehensive Measurements of Chinese Citizens’ Health Levels and Associated Influencing Factors

Healthcare ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 231 ◽  
Author(s):  
Chenyu Lu ◽  
Shulei Jin ◽  
Xianglong Tang ◽  
Chengpeng Lu ◽  
Hengji Li ◽  
...  
Keyword(s):  
Health Status ◽  
Influencing Factors ◽  
Spatial Clustering ◽  
Temporal Stability ◽  
Spatial Differentiation ◽  
Entropy Method ◽  
Practical Significance ◽  
Measurement Models ◽  
Spatio Temporal ◽  
Urbanization Rate

Health is the basis of a good life and a guarantee of a high quality of life. Furthermore, it is a symbol of social development and progress. How to further improve the health levels of citizens and reduce regional differences in citizens’ health status has become a research topic of great interest that is attracting attention globally. This study takes 31 provinces (municipalities and autonomous regions) of China as the research object. Through using GIS (Geographic Information System) technology, the entropy method, spatial autocorrelation, stepwise regression, and other quantitative analysis methods, measurement models and index systems are developed in order to perform an analysis of the spatio-temporal comprehensive measurements of Chinese citizens’ health levels. Furthermore, the associated influencing factors are analyzed. It has important theoretical and practical significance. The conclusions are as follows: (1) Between 2002 and 2018, the overall health levels of Chinese citizens have generally exhibited an upward trend. Moreover, for most provinces, the health levels of their citizens have improved dramatically, although some provinces, such as Tianjin and Henan, showed a fluctuating downward trend, suggesting that the health levels of citizens in these regions displayed a tendency to deteriorate. (2) The health levels of citizens from China’s various provinces showed clear spatial distribution characteristics of clustering, as well as an obvious spatial dependence and spatial heterogeneity. As time goes by, the degree of spatial clustering with regard to citizens’ health levels tends to weaken. The health levels of Chinese citizens have developed a certain temporal stability, the overall health status of Chinese citizens shows a spatial differentiation of a northeast–southwest distribution pattern. (3) The average years of education and urbanization rate have a significant positive effect on the improvement of citizens’ health levels. The increase of average years of education and urbanization rate can promote the per capita income, which certainly could help improve citizens’ health status. The Engel coefficient, urban–rural income ratio, and amount of wastewater discharge all pose a significant negative effect on the improvement of citizens’ health levels, these three factors have played important roles in hindering the improvements of citizen health.

scholarly journals Coupling and Coordination Level of the Population, Land, Economy, Ecology and Society in the Process of Urbanization: Measurement and Spatial Differentiation

2021 ◽  
Vol 13 (6) ◽  
pp. 3171
Author(s):  
Xuesong Sun ◽  
Zaisheng Zhang
Keyword(s):  
Spatial Differentiation ◽  
Entropy Method ◽  
Market Mechanism ◽  
Hebei Province ◽  
Sustainable Urban Development ◽  
Practical Significance ◽  
Coordinated Development ◽  
Rapid Urbanization ◽  
The Difference ◽  
Coordination Degree

Coupled and coordinated development is key to improving the level of regional urbanization and sustainable urban development and has important practical significance for solving a series of problems that arise in the process of rapid urbanization. First, from the perspective of system coupling, the development mechanism of the urbanization internal subsystems was deconstructed into five dimensions: population, land, economy, ecology and society. Second, based on data from 2017, the coupling coordination degree of urbanization in 13 cities in the Beijing–Tianjin–Hebei region was measured using the entropy method and a coupling coordination model. Finally, the spatial differences in the levels of subsystem development, comprehensive development and coupling and coordination development of urbanization were analyzed using spatial analysis tools. The results indicate that there are significant differences in the development indices of urbanization subsystems in the Beijing–Tianjin–Hebei region, among which the economic and social development indices have the greatest differences, and the ecological development index has the smallest. The comprehensive urbanization index shows a core–periphery distribution pattern, in which Beijing and Tianjin have the highest values, the cities in middle-southern Hebei Province generally have lower values, and the cities in northern Hebei Province have the lowest values. The coupling coordination level of urbanization in the Beijing–Tianjin–Tangshan region and Shijiazhuang, the capital of Hebei Province, is high, and the difference is small. In contrast, in middle-southern and northern Hebei Province, the coupling coordination degree of urbanization is generally low, and the difference is large. Based on the current situation of urbanization in the Beijing–Tianjin–Hebei region, policy suggestions are proposed from the perspectives of strengthening the market mechanism of urbanization, adjusting the regional industrial structure and attaching importance to the coupled and coordinated development of urbanization.

scholarly journals MODELAGEM DO COMPORTAMENTO LÍQUIDO-VAPOR EM EQUILÍBRIO ISOBÁRICO PARA A MISTURA HEXAMETILDISILOXANO + ACETATO DE SEC-BUTILA

e-xacta ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 21
Author(s):  
Plínio Ribeiro Rodrigues ◽  
Jéssica Magalhães Neves Nunes
Keyword(s):  
Experimental Data ◽  
Binary System ◽  
Butyl Acetate ◽  
System Modeling ◽  
Equilibrium Composition ◽  
Thermodynamic System ◽  
State Equation ◽  
High Accuracy ◽  
Actual Behavior ◽  
Average Accuracy

O hexametildisiloxano (HMDSO) e o acetato de sec-butila (ACSB) são compostos orgânicos utilizados em diversas aplicações tecnológicas, dentre elas a síntese química de vários produtos de interesse farmacêutico. No presente trabalho, as composições da mistura dos compostos em equilíbrio foram determinadas por meio do método Bolha P, calculado pela equação de estado cúbica com parâmetros de Peng-Robinson para a pressão de 101,3 kPa. Os erros médios percentuais entre os dados calculados e os valores experimentais também foram determinados, o que permitiu mostrar a precisão do modelo estudado em simular o sistema termodinâmico. Dessa maneira, o modelo mostrou-se útil para o cálculo da composição do equilíbrio do sistema binário avaliado, refletindo o comportamento real da mistura com precisão média de 90,57%, sendo, portanto, adequado a aplicações tecnológicas que exijam exatidão relativamente elevada e servindo de base para estudos futuros de modelagem do sistema HMDSO + ACSB. AbstractHexamethyldisiloxane (HMDSO) and sec-butyl acetate (ACSB) are organic compounds used in various technological applications, such as the chemical synthesis of various products of pharmaceutical interest. In the present work, mixture compositions of the compounds in equilibrium were determined by the Bubble P method, calculated by the cubic state equation with Peng-Robinson parameters for the pressure of 101.3 kPa. Mean percentage errors between the calculated and the experimental data were also determined, which allowed to indicate the precision of the model studied for the thermodynamic system modeling. In this way, the model proved to be useful for calculating the equilibrium composition of the evaluated binary system, reflecting the actual behavior of the mixture with an average accuracy of 90.57%; and is therefore suitable for technological applications that require relatively high accuracy and serving as basis for HMDSO + ACSB system future modeling studies.

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