Resilient behavior and permanent deformations of triaxial geogrid stabilized bases over weak subgrade

Geogrid has been playing an important role in solving geotechnical problems such as paved/unpaved roads constructed on weak subgrade. Geogrid provides lateral confinement to resist the lateral movement of aggregates by the interlocking action that occurs between geogrid apertures and surrounding aggregates. The inclusion of geogrid influences the resilient behavior of stabilized bases and benefits the stabilized bases by reducing permanent deformations (i.e. rutting). However, the resilient behavior and the accumulation mechanism of permanent deformations have not been well understood. In this study, cyclic and static plate loading tests were conducted on test sections of geogrid stabilized bases over subgrade under various loading intensities. The test sections were constructed in a geotechnical box with dimensions of 2 m (W) × 2.2 m (L) × 2 m (H) at the University of Kansas. The vertical and horizontal pressures along the interface were monitored by earth pressure cells with varying distances away from the centerline of test sections. Permanent and resilient deformations were monitored by LVDTs installed at 0, 0.25, 0.5, and 0.75 m away from the center. The results show that both the vertical and horizontal stresses were redistributed due to the inclusion of geogrids. Vertical stresses were distributed to a wider area, while horizontal stresses were confined to a smaller area close to the loading plate. The presence of geogrids reduced permanent deformations but increased resilient deformations. An analytical solution of the geogrid-stabilized layered elastic system was derived to evaluate the change of earth pressures induced by the inclusion of geogrids. Confinement effect and tensioned membrane effect were treated as external stresses applied at the interface. The base course was treated as transversely-isotropic to capture the modulus degradation at the horizontal direction. Results show that vertical stresses at the interface decreased and horizontal stresses along the centerline increased due to the inclusion of geogrids. The geogrid stabilized sections had higher lateral earth pressure coefficients along the centerline. A simple hypoplastic model was adopted to simulate the resilient behavior of stabilized soils (i.e. with higher lateral earth pressure coefficients). The results show that the soil sample under a stabilized condition had a higher resilient deformation under unloading n as compared with that under an unstabilized condition. The confinement and tensioned membrane effect due to the inclusion of geogrids reduced the permanent deformations not only at the loading stage, but also at the unloading stage

Response of carbon isotopic compositions of Early-Middle Permian coals in North China to palaeo-climate change

To investigate the magnitude to which the carbon isotopic ratio (delta C-13) varies in coals in response to their contemporary terrestrial environment, the Early-Middle Permian Huainan coals (including coals from the Shanxi Formation, Lower Shihezi Formation and Upper Shihezi Formation) in North China were systematically sampled. A 2.5 parts per thousand variation range of delta C-13 values (-25.15%o to -22.65%o) was observed in Huainan coals, with an average value of -24.06 parts per thousand. As coal diagenesis exerts little influence on carbon isotope fractionation, delta C-13 values in coals were mainly imparted by those of coal -forming flora assemblages which were linked to the contemporary climate. The delta C-13 values in coals from the Shanxi and Lower Shihezi Formations are variable, reflecting unstable climatic oscillations. Heavy carbon isotope is enriched in coals of the Capitanian Upper Shihezi Formation, implying a shift to high positive delta C-13 values of coeval atmospheric CO2. Notably, our study provides evidence of the Kamura event in the terrestrial environment for the first time

An Analysis Oncrude Oil Price Mutation in View of Zeeman's Catastrophe Machine

AbstractWith the acceleration of internationalmarket integration and the frequent outbreak of international political and economic events, the volatility of oil priceshas continued toincrease in recent years. As the main source of energy, crude oil plays an important role in the development of a country's economy. Therefore, it is meaningful to study the mutation of oil prices. Based on the Zeeman's catastrophe machine, USDX and excess demand are selected as two main factors to construct the catastrophe model, which helps to explain the structural relationship between USDX and excess demand when the crude oil price mutates

CD147 promotes melanoma cell growth via SOX4-mediated glycolytic metabolism

Purpose: To determine the functional roles of cluster of differentiation 147 (CD147) in glycolysis in melanoma cells.Methods: CD147 expression in melanoma tissue and adjacent normal tissue was determined using quantitative real time polymrase chain reaction (qRT-PCR) and immunohistochemistry. Cell Counting Kit-8 (CCK-8) and colony formation assays were used to evaluate cell viability and colony formation, respectively. The role of CD147 in glycolysis in melanoma cells was investigated by determining glucose uptake, production of lactate, and cellular level of ATP.Results: CD147 was enhanced more in melanoma tissue than that in the adjacent normal tissue (p < 0.001). CD147 overexpression promoted the viability and colony formation of melanoma cells. On the other hand, CD147 silencing decreased the viability and colony formation of melanoma cells. Glucose uptake, production of lactate, and cellular level of ATP were upregulated in melanoma cells by CD147 overexpression and downregulated by shRNA-mediated depletion of CD147. CD147 increased expression of C-X-C motif chemokine ligand 1 (CXCL1) to activate the sex-determining region Y-related high-mobility group box 4 (SOX4) pathway. Knockdown of CXCL1 attenuated the positive regulatory effect of CD147 on SOX4. Besides, overexpression of SOX4 reversed the suppressive effects of CD147 silencing on melanoma cell viability, colony formation, and glycolysis.Conclusion: CD147 contributes to melanoma cell growth via upregulation of SOX-mediated glycolysis, thus providing a therapeutic avenue for the management of melanoma. Keywords: Cluster of differentiation 147, CD147, Sex-determining region Y-related high-mobility group box 4, Melanoma, Cell growth, Glycolysi