Analysis of Elastic–Plastic Problems Using the Improved Interpolating Complex Variable Element Free Galerkin Method

A numerical model for the two-dimensional nonlinear elastic–plastic problem is proposed based on the improved interpolating complex variable element free Galerkin (IICVEFG) method and the incremental tangent stiffness matrix method. The viability of the proposed model is verified through three elastic–plastic examples. The numerical analyses show that the IICVEFG method has good convergence. The solutions using the IICVEFG method are consistent with the solutions obtained from the finite element method using the ABAQUS program. Moreover, the IICVEFG method shows greater computing precision and efficiency than the non-interpolating meshless methods.

From static alteration to mylonitization: a nano- to micrometric study of chloritization in granitoids with implications for equilibrium and fluid percolation length scales

<p>Strain accommodation in upper crustal rocks is often accompanied by fluid-mediated crystallization of phyllosilicates, which influence rock strength and shear zone formation. The composition of these phyllosilicates is commonly used for pressure-temperature-time constraints of deformation events, although it is often highly heterogeneous. This study investigates the reactions producing a phyllosilicate, chlorite, in and below greenschist-facies conditions and the variations in chlorite composition, along a strain gradient in the Bielsa granitoid (Axial Zone, Pyrenees). Compositional maps of chlorite (including iron speciation) are compared to nanostructures observed by transmission electron microscopy in increasingly-strained samples and related to mechanisms of fluid percolation and scales of compositional homogenisation. In the Bielsa granitoid, altered at the late Variscan, Alpine-age shear zones are found with high strain gradients. The undeformed granitoid exhibits local equilibria, pseudomorphic replacement and high compositional heterogeneities in chlorite. This is attributed to: (i) variable element supply and reaction mechanisms observed at nanoscale and (ii) little interconnected intra- and inter-grain nanoporosity causing isolation of fluid evolving in local reservoirs. In samples with discrete and mm-sized fractures, channelized fluid triggered the precipitation of homogeneous Alpine chlorite in fractures, preserving late-Variscan chlorite within the matrix. In low-grade mylonites, where brittle-ductile deformation is observed, micro-, nano-cracks and defects allows the fluid percolating into the matrix at the scale of hundreds of µm. This results in a more pervasive replacement of late-Variscan chlorite by Alpine chlorite. Local equilibria and high compositional heterogeneities in phyllosilicates as chlorite are therefore preserved according (i) matrix-fracture porosity contrasts at nanoscale and (ii) the location and interconnection of nanoporosity between crystallites of phyllosilicates that control reaction mechanisms and element mobility. In low grade mylonites, mineral and compositional replacement remains incomplete despite the high strain.</p>

Divergent Adaptation Strategies of Vascular Facultative Epiphytes to Bark and Soil Habitats: Insights from Stoichiometry

Understanding the stoichiometric traits of plants is critical for studying their ecological adaptation strategies. Facultative epiphytes (which can also live on the ground) are an important component of epiphytic flora of montane forest ecosystems. However, a key gap persists in our understanding how facultative epiphytes can adapt different nutritional conditions of ground and canopy habitats? To study adaptive strategies of facultative epiphytes and the characteristics of the content and stoichiometric homeostasis of C, N, and P elements, we conducted a field experiment and a greenhouse N and P additions cultivation experiment. We found that epiphytic individuals of facultative epiphytes showed lower C:N and C:P ratios, higher variation in elemental composition, and more pronounced N limitation than terrestrial individuals. Moreover, facultative epiphytes showed strong control over the elemental composition of leaves, and their stoichiometric homeostasis of leaves and stems were stronger than roots. Furthermore, the homeostasis of facultative epiphytes decreased in the order N > P. Our results indicated that epiphytic and terrestrial individuals of facultative epiphytes have difference in nutrient limitation, and they use plastic strategies in different habitats. Epiphytic individuals survive in the intermittent habitat through luxury consumption of nutrient while terrestrial individuals were relatively conservative nutrient users. Furthermore, our results implied that facultative epiphytes maintain stable metabolic leaf activity via variable element concentrations of roots to adapt to highly heterogeneous forest habitats.

From Receiving Meaning To Constructing Meaning: An Analytical Historical of the Reader's Role in the Literary Work

The study of the connection between the reader and the meaning of the literary text developed throughout the ages, and critics went in different directions in their analysis of the nature of that connection as well as the reader’s role on the literary text. In this context, the proposed study traces this relationship’s development to analyze the following: (1) the role played by the German Constance School in transforming the reader’s role from being a consumer reader to become a participant in the construction of meaning, and to highlight the procedures used by the founders of this school to facilitate understanding the reader’s new role. (2) the study sheds light on the way in which the critic Murād Mabrūk in his theory about “the literary communication” conveyed the concepts of the Constance School about the reader’s role in producing meaning to open up a new horizon for studying the meaning of the literary text. The study concludes, through its use of the historical analytic method, that: (1) the historical development of the mechanism of interpretation of meaning is based on the idea of the shift in interaction with meaning from the negative interaction in which the meaning is a constant element discovered by the reader to the positive interaction in which the meaning is a variable element resulting from the interaction between the text, Author, and reader.

The Improved Interpolating Complex Variable Element Free Galerkin Method for Two-Dimensional Potential Problems

In this paper, the improved interpolating complex variable moving least squares (IICVMLS) method is applied, in which the complete basis function is introduced and combined with the singular weight function to achieve the orthometric basis function. Then, the interpolating shape function is achieved to construct the interpolating trial function. Incorporating the IICVMLS method and the Galerkin integral weak form, an improved interpolating complex variable element free Galerkin (IICVEFG) method is proposed to solve the 2D potential problem. Because the essential boundary conditions can be straightaway imposed in the above method, the expressions of final dispersed matrices are more concise in contrast to the non-interpolating complex variable meshless methods. Through analyzing four specific potential problems, the IICVEFG method is validated with greater computing precision and efficiency.

The Improved Complex Variable Element-Free Galerkin Method for Bending Problem of Thin Plate on Elastic Foundations

In this paper, the improved complex variable element-free Galerkin (ICVEFG) method is proposed for solving the bending problem of thin plate on elastic foundations. In the ICVEFG method, the approximation function regarding the deflection of thin plate is formed with the improved complex moving least-squares (ICVMLS) approximation, the discrete equation is obtained from Galerkin weak form of bending problem of thin plate on different elastic foundations, and essential boundary conditions are considered based on penalty method. As the ICVMLS approximation is based on the complex variable theory, it can obtain the shape function quickly with high precision. Three sample problems are used to discuss the advantages of the ICVEFG method, and the numerical results show that the ICVEFG method presented in this paper has a fast convergence speed and great computational accuracy.