Revaluating coal permeability-gas pressure relation under various gas pressure differential conditions

Identifying changes in coal permeability with gas pressure and accurately codifying mean efective stresses in laboratory samples are crucial in predicting gas-fow behavior in coal reservoirs. Traditionally, coal permeability to gas is assessed using the steady-state method, where the equivalent gas pressure in the coal is indexed to the average of upstream and downstream pressures of the coal, while ignoring the nonlinear gas pressure gradient along the gas fow path. For the fow of a compressible gas, the traditional method consistently underestimates the length/volume-averaged pressure and overestimates mean efective stress. The higher the pressure diferential within the sample, the greater the error between the true mean pressure for a compressible fuid and that assumed as the average between upstream and downstream pressures under typical reservoir conditions. A correction coefcient for the compressible fuid pressure asymptotes to approximately 1.3%, representing that the error in mean pressure and efective stress can be on the order of approximately 30%, particularly for highly pressure-sensitive permeabilities and compressibilities, further amplifying errors in evaluated reservoir properties. We utilized this volume-averaged pressure and efective stress to correct permeability and compressibility data reported in the literature. Both the corrected initial permeability and the corrected pore compressibility were found to be smaller than the uncorrected values, due to the underestimation of the true mean fuid pressure, resulting in an overestimation of reservoir permeability if not corrected. The correction coefcient for the initial permeability ranges from 0.6 to 0.1 (reservoir values are only approximately 40% to 90% of laboratory values), while the correction coefcient for pore compressibility remains at approximately 0.75 (reservoir values are only approximately 25% of laboratory value). Errors between the uncorrected and corrected parameters are quantifed under various factors, such as confning pressure, gas sorption, and temperature. By analyzing the evolutions of the initial permeability and pore compressibility, the coupling mechanisms of mechanical compression, adsorption swelling, and thermal expansion on the pore structure of the coal can be interpreted. These fndings can provide insights that are useful for assessing the sensitivity of coal permeability to gas pressure as truly representative of reservoir conditions.

Influence of Steam and Sulfide on High Temperature Selective Catalytic Reduction

The influences of steam and sulfide on the efficiency of NOx reduction using ammonia(NH_(3))over the nanometer-class V-W/Ti catalyst in conditions of high temperature is experimentally investigated using a steady-flow reactor.The results showed that selective catalytic reduction(SCR)is inhibited by H_(2)O at low temperature,but higher NO conversion efficiency is achieved at high temperature since the reaction of NH_(3) oxidized by O_(2) to NOx is inhibited by H_(2)O.The activity of SCR is promoted by SO_(2) in the temperature range of 200~500℃,the NO conversion efficiency was improved to 98%from 94%by adding SO_(2).SCR would be improved at 350~500℃ when H_(2)O and SO_(2) exist at the same time.Furthermore,the positive influence to the NOx conversion was proved in the presence of H_(2)O and SO_(2) as a result of the European Stationary Cycle test.

<i>In Vitro</i>Study of the Nephrotoxicity of Tripterygium Tablet Extract and Triptolide in Monolayer HK-2 Cells Cultured in a Transwell Chamber

We established a monolayer polarized cell model using human kidney 2 (HK-2) cells cultured in a transwell chamber to examine the changes in the morphology and physiological functions of human-derived renal proximal tubular epithelial cells caused by tripterygium tablet extract (TTE) and triptolide. HK-2 cells were cultured on PCF membranes to form a complete monolayer of cells. A MTT assay was used to select 10, 40, 160, 640 μg·ml-1 TTE or 4, 16, 64, 256 ng·ml-1 triptolide to treat HK-2 monolayer cells. After 24 hours, a FITC permeability assay was performed;GGT, LDH and NAG secretion on the apical (AP) and basolateral (BL) sides of the cells by HK-2 cells were examined. The morphology and the monolayer structure of HK-2 cells was observed via optical microscope and scanning electron microscope, respectively. The effect on the cytoskeleton of HK-2 cells was observed under a fluorescence microscope. The IC50 of TTE was 277.122 μg·ml-1, and the IC50 of triptolide was 148.035 ng·ml-1. Compared with the DMSO group, the FITC leakage rate with TTE 160, 640 μg·ml-1 treated group and 4 - 256 ng·ml-1 triptolide dose group exhibited statistically significant increase. TTE significantly increased secretion of GGT and LDH at 160, 640 μg·ml-1, meanwhile, dramatically increased the AP/BL ratio of LDH at 160 μg·ml-1;triptolide significantly increased secretion and AP/BL ratio of GGT and LDH at 256 ng·ml-1. The morphological observations via optical and electron microscope indicated various degrees of damage to HK-2 cells by TTE and triptolide, and the degree of damage correlated positively with the dosage of the tested articles. Compared with DMSO group, the cellular damage degrees at TTE dosages of 40 - 640 μg·ml-1 and triptolide dose group at 16, 256 ng·ml-1 exhibited statistically significant differences via observation under optical microscope. Both TTE and triptolide caused various degrees of shortening and thickening of intracellular F-actin bundles of HK-2 cells;aggravation of these changes was observed with increasing drug dosage. Thus, we conclude both TTE and triptolide caused damage to human renal proximal tubular epithelial cells at certain dosages;TTE dosages of 40 μg·ml-1 and above and triptolide dose group at 16 ng·ml-1 and above exhibited the changes in the morphology, meanwhile, TTE dosages of 160 μg·ml-1 and above and triptolide dose group at 256 ng·ml-1 exhibited the changes in the physiological functions such as secretion of HK-2 cell.

Flexible resource allocation optimization model considering global K-means load clustering and renewable-energy consumption

Vigorously developing flexible resources in power systems will be the key to building a new power system and realizing energy trans-formation.The investment construction cost and operation cost of various flexible resources are different,and the adjustment ability is different in different timescales.Therefore,the optimization of complementary allocation of various resources needs to take into account the economy and adjustment ability of different resources.In this paper,the global K-means load clustering model is pro-posed and the 365-day net load is reduced to eight typical daily net loads by clustering.Secondly,a two-level optimization model of flexible resource complementary allocation considering wind power and photovoltaic consumption is constructed.The flexible resources involved include the flexible transformation of thermal power,hydropower,pumped storage,energy storage,and demand response.The upper-layer model optimizes the capacity allocation of various flexible resources with the minimum investment and construction cost as the goal and the lower layer optimizes the operating output of various units with the minimum operating cost as the goal.The results of the example analysis show that the flexible capacity of thermal power units has nothing to do with the abandonment rate of renewable energy.As the abandonment rate of renewable energy decreases,the optimal capacity of pumped storage,electrochemical energy storage,and hydropower units increases.When the power-abandonment rate of renewable energy is 5%,the optimal allocation capacity of thermal power flexibility transformation,pumped storage,electrochemical energy storage,hydropower unit,and adjustable load in Province A is 5313,17090,5830,72113,and 4250 MW,respectively.Under the condition that the renewable-energy abandonment rate is 0,5%,and 10%respectively,the configured capacity of pumped storage is 20000,17090,and 14847 MW,respectively.

Constructing origami power generator from one piece of electret thin film and application in AIenabled transmission line vibration monitoring

One of the crucial issues for applying electret/triboelectric power generators in the Internet of Things(IoT)is to take full advantage of specific high voltage signals and enable self-powered sensing.Therefore,inspired by Miura-origami,we present an innovative origami power generator(OPG)constructed from only one piece of electret thin film.The Miura-origami architecture realizes a generator with excellent deformability and stretchability and makes it unnecessary for any auxiliary support structure during the compress-release cycle.Various parameters of the generator are intensively investigated,including the excitation accelerations,excitation displacements,numbers of power generation units and deformation degree of the device.When stimulated with 5.0 g acceleration at 15 Hz frequency,the generator with 8 generation units can obtain an instantaneous peak-to-peak voltage and a remarkable optimum peak power of 328 V and 2152μW at 50MΩ,respectively.In addition,the regulable shape and multiple generation modes of the device greatly improve its applicability in various vibration energy collection requirements.Based on the above results,a hexagonal electret generator integrated with six-phase OPGs is developed as a“Buoy on Sky,”after which the signal waveforms generated from internal power generators are recognized with 92%accuracy through a neural network algorithm that identifies the vibration conditions of transmission lines.This work demonstrates that a fusion of origami art and energy conversion techniques can achieve a multifunctional generator design satisfying the requirements for IoT applications.

Framework of Decentralized Multi-chain Data Management for Power Systems

With the wide application of advanced information and communication technology(ICT),power systems are becoming more reliable,more efficient and self-healing.Meanwhile more sophisticated cyber-attacks have appeared,e.g.false data injection(FDI)attacks,which deeply affect the state estimation of power systems and can lead to destructive consequences.To better manage and protect measurement data in power systems,we propose a blockchain-based multi-chain framework,taking advantage of the existing infrastructure.In this framework,measurements from sensors are mined into blocks by base stations using Practical Byzantine Fault Tolerance(PBFT)as the consensus protocol.We analyze the security of the proposed framework and carry out simulations to show its superiority compared to existing systems.The result of the simulations further provides guidance for how to structure the networking in the proposed framework.

东亚福利体制的社会资本前提假设及其检验

区别于欧美福利制度,东亚福利体制的特点在于福利国家"功能替代物"的福祉作用,特别是社会资本作为重要的福祉资源受到关注。可以说,东亚各国(地区)拥有丰富的可以促进国民福祉的社会资本是东亚福利体制的前提假设。本文利用包含东亚13个国家(地区)的亚洲民主动态调查数据,对东亚福利体制的社会资本假设进行了实证检验。分析结果显示,社会资本与东亚各国民众的福祉整体呈正相关关系,东北亚国家(地区)的社会资本呈现出同质性特点,而东南亚国家(地区)呈现出异质性特征。东北亚和东南亚的社会资本特征的差异主要源于传统文化、民族结构和历史经验。