The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Xiang Zhou - One of the best experts on this subject based on the ideXlab platform.
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increasing returns to education changing labor force structure and the rise of earnings inequality in urban china 1996 2010
Social Forces, 2014Co-Authors: Xiang ZhouAbstract:Earnings inequality in urban China has grown rapidly the past two decades. During the same period, the composition of the urban labor force has been dramatically altered by three large-scale structural changes: (1) the expansion of tertiary education; (2) the decline of state sector employment; and (3) a surge in rural-to-urban migration. In this article, I examine how these institutional and demographic shifts have shaped the recent upswing in earnings inequality. Based on data from two nationally representative surveys, I use variance function regressions to decompose the growth in earnings inequality from 1996 to 2010 into four components: changes in between-group earnings gaps, changes in within-group earnings variation, and two types of composition Effects ( Distribution Effect and allocation Effect ). I also employ counterfactual simulations to evaluate the utility of different explanations. Results show that nearly half of the growth in earnings inequality during this period is due to increases in returns to education, and that the other half can be attributed to compositional changes in the labor force. The composition Effects stem chiefly from the expansion of tertiary education and the shrinkage of state sector employment.
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increasing returns to education changing labor force structure and the rise of earnings inequality in urban china 1996 2010
Social Forces, 2014Co-Authors: Xiang ZhouAbstract:Earnings inequality in urban China has grown rapidly the past two decades. During the same period, the composition of the urban labor force has been dramatically altered by three large-scale structural changes: (1) the expansion of tertiary education; (2) the decline of state sector employment; and (3) a surge in rural-to-urban migration. In this article, I examine how these institutional and demographic shifts have shaped the recent upswing in earnings inequality. Based on data from two nationally representative surveys, I use variance function regressions to decompose the growth in earnings inequality from 1996 to 2010 into four components: changes in between-group earnings gaps, changes in within-group earnings variation, and two types of composition Effects ( Distribution Effect and allocation Effect ). I also employ counterfactual simulations to evaluate the utility of different explanations. Results show that nearly half of the growth in earnings inequality during this period is due to increases in returns to education, and that the other half can be attributed to compositional changes in the labor force. The composition Effects stem chiefly from the expansion of tertiary education and the shrinkage of state sector employment.
Hadi Nasrabadi - One of the best experts on this subject based on the ideXlab platform.
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molecular simulation of the pore size Distribution Effect on phase behavior of methane confined in nanopores
Fluid Phase Equilibria, 2017Co-Authors: Bikai Jin, Hadi NasrabadiAbstract:Abstract An understanding of the phase behavior of hydrocarbons is important in the petroleum reservoir simulation. However, fluid phase behavior in a shale reservoir is substantially different from conventional behavior. Since fluids are stored inside nanopores of shale rocks, there is a strong interaction between the pore boundary and fluid molecules. Due to this interaction, the fluid molecules are distributed heterogeneously inside the nanopores and the phase diagram is shifted under confinement. Advanced theoretical procedures such as molecular simulations are needed to properly model the heterogeneous molecular Distribution inside the shale nanopores. Previous molecular simulation studies of nanoconfined hydrocarbon phase behavior have been limited to single pore size models. However, shale rocks usually have a wide pore size Distribution (PSD) and single pore-size models are not accurate enough to represent a real shale system. In this work, to understand the PSD Effect on the phase behavior, a recently proposed molecular simulation method, gauge-GCMC, is used to generate phase diagrams based on two types of cylindrical models (single pore and multiple pores, including one based on Eagle Ford shale rock). In single pore tests, the pore diameter is changed from 4 to 10 nm. Our results for multi-pore systems show that with an increasing pore size, the phase equilibrium properties approach the bulk values. Also, smaller pores cause a more significant shift in the phase diagram. Our results show that the small pores are filled before the large ones, which means that liquid will first be condensed in the small pores. In the Eagle Ford case, the pore model is designed by discretizing PSD data from experiments. The results show that it is possible to use a single pore model with a 10 nm diameter to represent the pore system of this shale sample.
Alexander V Neimark - One of the best experts on this subject based on the ideXlab platform.
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adsorption induced deformation of microporous carbons pore size Distribution Effect
Langmuir, 2008Co-Authors: Piotr Kowalczyk, A Ciach, Alexander V NeimarkAbstract:We present a thermodynamic model of adsorption-induced deformation of microporous carbons. The model represents the carbon structure as a macroscopically isotropic disordered three-dimensional medium composed of stacks of slit-shaped pores of different sizes embedded in an incompressible amorphous matrix. Adsorption stress in pores is calculated by means of Monte Carlo simulations. The proposed model reproduces qualitatively the experimental nonmonotonic dilatometric deformation curve for argon adsorption on carbide-derived activated carbon at 243 K and pressure up to 1.2 MPa. The elastic deformation (contraction at low pressures and swelling at higher pressures) results from the adsorption stress that depends strongly on the pore size. The pore size Distribution determines the shape of the deformation curve, whereas the bulk modulus controls the extent of the sample deformation.
Wang Shuang - One of the best experts on this subject based on the ideXlab platform.
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Micromechanical Prediction Model of Viscoelastic Properties for Asphalt Mastic Based on Morphologically Representative Pattern Approach
Digital Commons @ Michigan Tech, 2020Co-Authors: Wang Zhichen, Guo Naisheng, Xu Yang, Wang ShuangAbstract:This paper is devoted to the introduction of physicochemical, filler size, and Distribution Effect in micromechanical predictions of the overall viscoelastic properties of asphalt mastic. In order to account for the three Effects, the morphologically representative pattern (MRP) approach was employed. The MRP model was improved due to the arduous practical use of equivalent modulus formula solution. Then, a homogeneous morphologically representative model (H-MRP) with the explicit solution was established based on the homogenization theory. Asphalt mastic is regarded as a composite material consisting of filler particles coated structural asphalt and free asphalt considering the physicochemical Effect. An additional interphase surrounding particles was introduced in the H-MRP model. Thus, a modified H-MRP model was established. Using the proposed model, a viscoelastic equation was derived to predict the complex modulus and subsequently the dynamic modulus of asphalt mastic based on the elastic-viscoelastic correspondence principle. The dynamic shear rheological tests were conducted to verify the prediction model. The results show that the predicted modulus presents an acceptable precision for asphalt mastic mixed with 10% and 20% fillers volume fraction, as compared to the measured ones. The predicted modulus agrees reasonably well with the measured ones at high frequencies for asphalt mastic mixed with 30% and 40% fillers volume fraction. However, it exhibits underestimated modulus at low frequencies. The reasons for the discrepancy between predicted and measured dynamic shear modulus and the factors affecting the dynamic shear modulus were also explored in the paper
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Micromechanical Prediction Model of Viscoelastic Properties for Asphalt Mastic Based on Morphologically Representative Pattern Approach
'Hindawi Limited', 2020Co-Authors: Wang Zhichen, Guo Naisheng, Xu Yang, Wang ShuangAbstract:© 2020 Zhichen Wang et al. This paper is devoted to the introduction of physicochemical, filler size, and Distribution Effect in micromechanical predictions of the overall viscoelastic properties of asphalt mastic. In order to account for the three Effects, the morphologically representative pattern (MRP) approach was employed. The MRP model was improved due to the arduous practical use of equivalent modulus formula solution. Then, a homogeneous morphologically representative model (H-MRP) with the explicit solution was established based on the homogenization theory. Asphalt mastic is regarded as a composite material consisting of filler particles coated structural asphalt and free asphalt considering the physicochemical Effect. An additional interphase surrounding particles was introduced in the H-MRP model. Thus, a modified H-MRP model was established. Using the proposed model, a viscoelastic equation was derived to predict the complex modulus and subsequently the dynamic modulus of asphalt mastic based on the elastic-viscoelastic correspondence principle. The dynamic shear rheological tests were conducted to verify the prediction model. The results show that the predicted modulus presents an acceptable precision for asphalt mastic mixed with 10% and 20% fillers volume fraction, as compared to the measured ones. The predicted modulus agrees reasonably well with the measured ones at high frequencies for asphalt mastic mixed with 30% and 40% fillers volume fraction. However, it exhibits underestimated modulus at low frequencies. The reasons for the discrepancy between predicted and measured dynamic shear modulus and the factors affecting the dynamic shear modulus were also explored in the paper
Bikai Jin - One of the best experts on this subject based on the ideXlab platform.
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molecular simulation of the pore size Distribution Effect on phase behavior of methane confined in nanopores
Fluid Phase Equilibria, 2017Co-Authors: Bikai Jin, Hadi NasrabadiAbstract:Abstract An understanding of the phase behavior of hydrocarbons is important in the petroleum reservoir simulation. However, fluid phase behavior in a shale reservoir is substantially different from conventional behavior. Since fluids are stored inside nanopores of shale rocks, there is a strong interaction between the pore boundary and fluid molecules. Due to this interaction, the fluid molecules are distributed heterogeneously inside the nanopores and the phase diagram is shifted under confinement. Advanced theoretical procedures such as molecular simulations are needed to properly model the heterogeneous molecular Distribution inside the shale nanopores. Previous molecular simulation studies of nanoconfined hydrocarbon phase behavior have been limited to single pore size models. However, shale rocks usually have a wide pore size Distribution (PSD) and single pore-size models are not accurate enough to represent a real shale system. In this work, to understand the PSD Effect on the phase behavior, a recently proposed molecular simulation method, gauge-GCMC, is used to generate phase diagrams based on two types of cylindrical models (single pore and multiple pores, including one based on Eagle Ford shale rock). In single pore tests, the pore diameter is changed from 4 to 10 nm. Our results for multi-pore systems show that with an increasing pore size, the phase equilibrium properties approach the bulk values. Also, smaller pores cause a more significant shift in the phase diagram. Our results show that the small pores are filled before the large ones, which means that liquid will first be condensed in the small pores. In the Eagle Ford case, the pore model is designed by discretizing PSD data from experiments. The results show that it is possible to use a single pore model with a 10 nm diameter to represent the pore system of this shale sample.