The Nature, Features and Governance of State-owned Energy Enterprises

AbstractThe state-owned energy enterprise, in essence, is a kind of contractual arrangement. In order to maximize national interests, the state delegates executives to operate business in the energy sector by combining energy resources with other resources through a series of contracts. Yet the features of state-owned energy enterprises, such as monopoly, negative externalities, strong asset specificity and high opportunism risks, could give rise to some negative impacts. So, in order to avoid negative impacts, improve governance efficiency and achieve harmony between man and nature, we should improve government regulation system, establish a more efficient board, implement a reasonable operator incentive system, and revise the supervision and constraint mechanisms

Reconstitution of Kidney Side Population Cells after Ischemia-Reperfusion Injury by Self-Proliferation and Bone Marrow-Derived Cell Homing

The aim of this study was to examine the contribution of side population (SP) cells from kidney and bone marrow for reconstitution of kidney SP pools after ischemia-reperfusion injury (IRI). The SP and non-SP cells in kidneys following IRI were isolated and serially assessed by fluorescence-activated cell sorting. The apoptosis, proliferation, phenotype, and paracrine actions of SP cells were evaluated in vitro and in vivo. Results indicated that the SP cells from ischemic kidney were acutely depleted within one day following renal IRI and were progressively restored to baseline within 7 days after IRI, through both proliferation of remaining kidney SP cells and homing of bone marrow-derived cells to ischemic kidney. Either hypoxia or serum deprivation alone increased apoptosis of SP cells, and a combination of both further aggravated it. Furthermore, hypoxia in vivo and in vitro induced the increase in the secretion of vascular endothelial growth factor, insulin-like growth factor 1, hepatocyte growth factor, and stromal cell-derived factor-1α in kidney SP but not non-SP cells. In summary, these results suggest that following renal IRI, kidney SP cells are acutely depleted and then progressively restored to baseline levels by both self-proliferation and extrarenal source, that is, bone marrow-derived cell homing

Research on the Macro-Mesoscopic Response Mechanism of Multisphere Approximated Heteromorphic Tailing Particles

AbstractThe shape of tailing particles is essential factors of their macroscopic mechanical properties. Scholars have studied the effects of controllable factors, such as loading method, confining pressure, and strain rate, on the strength of tailing sand. However, research on the tailing particle structure and shape through laboratory tests has proved to be difficult due to the uncertain and discrete tailing particle distribution. Thus, the macro-mesoscopic response of heteromorphic tailing particles is rarely investigated. In this paper, the macro-mesoscopic response of heteromorphic tailing particles is studied using multisphere approximation, and numerical simulation of triaxial tests on the particles is conducted. Nonlinear evolution patterns of porosity, internal friction angle, and cohesion of heteromorphic tailing particles with the variation of angularity were investigated using the flexible boundary program developed in this study, which revealed the intrinsic relationship between the mesostructure evolution mechanism and the macroscopic engineering characteristics of heteromorphic tailing particles. The research results showed that (1) changes in angularity led to tailing particle rearrangements and, in turn, porosity changes. With increased angularity and confining pressure, particle sphericity decreased, and the deviatoric and peak stress increased accordingly. In the meantime, the softening was more significant as the peak stress was exceeded, while the cohesive force generally increased. (2) With fixed particle shape and angularity, the internal friction angle decreased slightly as the effective confining pressure increased. (3) In the shearing process, the simulated contact force chain evolution of tailing particles with different shapes was similar. The disordered contact force chains gradually undergo directional connection, i.e., the increased confining pressure reduced the number of free tailing particles and increased the number of stressed particles. (4) The triaxial stress-strain and peak stress in rigid boundary simulations under different confining pressures were slightly lower than those in the flexible boundary simulations. However, the difference was insignificant, indicating the good feasibility and reasonability of rigid boundary simulations for the macroscopic mechanical behaviors in triaxial tests. The research results could offer more direct insights into the macro-mesoscopic response and mechanical mechanisms of nonspherical particles and provide references for the simulation of tailings at the microscopic levels

Linking Physics-Based Deterioration Model to Field-Based Condition Assessments for Improving Asset Management

69A3551847102Currently used asset management programs by various state departments of transportation (DOT) rely typically on field-based condition assessments (periodic inspections and deterioration curves) of bridges for planning repair and maintenance activities. However, field inspections are labor intensive and can be subjective. Furthermore, visual inspections rely on visible signs of deterioration on the exterior surface of a bridge (e.g., corrosion stains and cracks) and may miss severe localized deterioration hidden inside concrete, which could incur significant repair costs in the future. On the other hand, physics-based models rely on simulating the underlying deterioration mechanisms for predicting future deterioration. Several parameters used in physics-based models are often based on extrapolating laboratory data that is not representative of field conditions. Furthermore, the outputs of physics-based deterioration model (e.g., rebar area loss) cannot be translated to condition ratings and are therefore unusable in asset management programs of state DOTs. For addressing these limitations, this research aims to (1) determine a rational basis for linking the outputs of a physics-based corrosion model to field-based condition ratings, and (2) calibration of input parameters of physics-based corrosion model based on deterioration curves obtained from field-based assessments. This report presents a systematic procedure for achieving these two aims. An example bridge column owned by New York State DOT is used to demonstrate the procedure. Links between the surface crack width and spalling and bridge element condition rating were established based on the interpretation of condition ratings. Inputs of the corrosion model were calibrated by matching the crack widths and spalling interpreted from deterioration curves with the outputs of the physics-based corrosion model. This project is expected to improve asset management by supplementing the field-based condition assessments with physics-based deterioration models

Experimental Study on Failure Model of Tailing Dam Overtopping under Heavy Rainfall

AbstractUnusual rainfall is the primary cause of the failure of the tailing dams, and overtopping is the most representative model of the tailing dam failure. The upstream tailing dam was selected as the research object to study the whole process of breach extension and the overtopping dam-failure mechanism under the full-scale rainfall condition. The results showed that the significant size grading phenomenon in the front, middle, and end of the tailing pond was obvious due to the flow separation effect, and its average particle diameter was D50. At different moments of rainfall, the height of the infiltration line at different positions of the dam body was different; at the rainfall of 3600 s, the height of the infiltration line lagged behind the height of the tailing pond, and this phenomenon from the tail of pond to the outside of the dam slope became more obvious. After the rainfall of 3600 s, the height of the infiltration line lagging behind the water level in the pond basically disappeared, and the rate of infiltration line rise kept pace with the rate of water level. The process of overtopping dam-failure experienced dam overtopping (gully erosion), formation of a multistepped small “scarp,” breach rapid expansion, formation of large “scarp,” and burst (fan-shaped formation). The width and depth of the breach showed a positive correlation, and the widening rate of the breach was 3 to 8 times of the deepening rate, especially in the middle of the dam break, widening behavior occupied the dominant factor. The shape of the dam body after failure was parabolic, and the dam body had obvious elevation changes. These results provide the theoretical guidance and engineering application value for improving the theory and early warning model of the upstream tailing dam

RUNX3 Mediates Suppression of Tumor Growth and Metastasis of Human CCRCC by Regulating Cyclin Related Proteins and TIMP-1

Here we presented that the expression of RUNX3 was significantly decreased in 75 cases of clear cell renal cell carcinoma (CCRCC) tissues (p<0.05). Enforced RUNX3 expression mediated 786-O cells to exhibit inhibition of growth, G1 cell-cycle arrest and metastasis in vitro, and to lost tumorigenicity in nude mouse model in vivo. RUNX3-induced growth suppression was found partially to regulate various proteins, including inhibition of cyclinD1, cyclinE, cdk2, cdk4 and p-Rb, but increase of p27Kip1, Rb and TIMP-1. Therefore, RUNX3 had the function of inhibiting the proliferative and metastatic abilities of CCRCC cells by regulating cyclins and TIMP1