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An Improved Discontinuous Deformation Analysis to Solve Both Shear and Tensile Failure Problems
Wenjun Gong,Jing Hu,Zhigang Tao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5
This paper is mainly aimed to present an improved DDA (discontinuous deformation analysis) that can deal well with both shear and tensile failure problems. Firstly, the shear mechanism of DDA is detailed investigated. The results show that when handling the frictional interface, the critical shear resistance can be accurately determined only if the penalty value is carefully selected, however, when handling the cohesive interface, the critical shear resistance is significantly underestimated. The inaccurate prediction is due to the inconsistent distribution of normal force and shear force between the two vertex-to-edge contacts in one edge-to-edge contact. Here an edge-to-edge treatment is introduced into DDA. Secondly, to moderately reflect the tensile failure process of rock masses, a two-phase constitutive model is introduced into the DDA with edge-to-edge treatment, and the improved DDA is obtained. Finally, the improved DDA is used to simulate the failure process of gypsum centrifuge model. The results show the improved DDA can deal well with rock failure problems by shear or tension failure.
Wenjun Gong,Yunsheng Wang,Yujie Wang,Yonghong Luo 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12
For the prevention and mitigation of hazards, it is crucial to quantitatively analyze the seismic response of rock slopes. However, only a few studies have quantitatively analyzed the seismic response of rock slopes; these studies have considered topographic effects only and have neglected geological site effects, such as impedance contrasts and fractures, which are important factors affecting the seismic response of rock slopes, as revealed by multiple recent phenomena. Therefore, this study primarily aims to investigate the possibility of employing a numerical model for quantitatively analyzing the seismic response of rock slopes by considering the geological site effects. Herein, a discrete element method, i.e., discontinuous deformation analysis (DDA), was employed for the dynamic analyses, and a well-monitored rock slope, Mount Dong, was selected as the case study. In the proposed DDA model, horizontal and vertical ground motions were applied simultaneously. The different weathering degrees of the Mount Dong rock layers were considered to reflect the impedance contrasts, and the penalty value at the fractures was altered according to the stiffness for reflecting the fracture effects. Furthermore, a set of optimal boundary settings, especially for DDA, were applied to handle seismic dynamic problems. Results show that DDA can quantitatively reflect the seismic response of Mount Dong along a single direction, such as the horizontal direction, which is sufficient to satisfy engineering requirements. The peak ground acceleration amplification analyses indicate that: 1) a strong impedance contrast is more important than topographic effects for the seismic response of Mount Dong; and 2) in addition to the impedance of rock layers, widely spread fractures also play an important role in contributing to the seismic response anisotropy of rock slopes. Finally, spectral amplification analyses reveal that the responses of the inner and surface portion of Mount Dong are significant in a low- and high-frequency range, respectively.
Gong, Yingyun,Cao, Rui,Ding, Guolian,Hong, Sungguan,Zhou, Wenjun,Lu, Wenyun,Damle, Manashree,Fang, Bin,Wang, Chuhan C.,Qian, Justin,Lie, Natasha,Lanzillotta, Cristina,Rabinowitz, Joshua D.,Sun, Zheng Elsevier 2018 Molecular and cellular endocrinology Vol.471 No.-
<P><B>Abstract</B></P> <P>Nuclear receptors regulate gene expression by differentially binding to coactivators or corepressors in a ligand-dependent manner, which further recruits a set of epigenome-modifying enzymes that remodel chromatin conformation. Histone acetylation is a major epigenomic change controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDAC3 is the only HDAC that confers the enzymatic activity to the complexes nucleated by nuclear receptor corepressors NCoR and SMRT. To address the metabolic function of HDAC3, we have deleted it specifically in mouse skeletal muscles. We have performed the following omics profiling in skeletal muscles of these mice: (1) RNA-seq profiling of total RNA; (2) Global nuclear run-on (GRO-seq) analysis of nascent RNAs; (3) Chromatin immuno-precipitation (ChIP-seq) of HDAC3 at both early evening and early morning; (4) proteomics profiling with mass spectrometry; (5) snap-shot metabolomics profiling of water-soluble metabolites at the basal condition; (6) snap-shot metabolomics profiling of lipid species at the basal condition; (7) kinetic fluxomics analysis of glucose utilization using <SUP>13</SUP>C<SUB>6</SUB>-glucose <I>In vivo</I> during treadmill running exercise. These approaches have provided several novel insights into how nuclear receptors regulate circadian rhythm of skeletal muscle fuel metabolism, which has been published elsewhere. Here we present the original datasets and technical details during the execution, analysis, and interpretation of these omics studies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A mouse model with skeletal muscle-specific KO of HDAC3. </LI> <LI> <I>in vivo</I> RNA-seq, GRO-seq, and ChIP-seq identified relevance to circadian clock. </LI> <LI> Total proteome profiling in muscle samples. </LI> <LI> Metabolomics profiling identified disruption of BCAAs metabolism. </LI> <LI> Fluxomics with <SUP>13</SUP>C-glucose <I>in vivo</I> during treadmill running. </LI> </UL> </P>