Mechanisms that lead to different quantities of hydrocarbon accumulation in complex fault blocks are a major subject that impacts further development plans of oil and gas fields. To better understand ...such mechanisms, fault activity has been interpreted along with existing electron micrographs from the fault zone, petrophysical data, and the occurrence of the seismic pump. This enabled us to investigate the controlling mechanisms of the growth faults and other associated faults with the main growth fault in the Wang Guantun area that could have impacted hydrocarbon distribution. The results showed that the activity of Kongdong growth fault is periodic and intermittent, which produced strong seismic pumping action. Furthermore, a series of secondary faults were generated in adjacent strata due to the fault activity, which could have led to the formation of a secondary seismic pump source. A combination of these two incidents is believed to influence the differential distribution of hydrocarbons in the area, in fault-associated reservoirs. Ultimately, we correlated the activity of the growth fault to the strength of the pumping force causing the distribution of hydrocarbons in the active parts of the faults (pump source position) on the horizontal plane and vertically located reservoirs to be more dominant.
Training image (TI) is important for multipoint statistics simulation method (MPS), since it captures the spatial geological pattern of target reservoir to be modeled. Generally, one optimal TI is ...selected before applying MPS by evaluating the similarities between many TIs and the well interpretations of target reservoir. In this paper, we propose a new training image optimization approach based on the convolutional neural network (CNN). First, candidate TIs were randomly sampled several times to obtain the sample dataset. Then, the CNN was used to conduct transfer learning for all samples, and finally, the optimal TI of the conditioning well data is selected through the trained CNN model. By taking advantage of the strong learning ability of CNN in image feature recognition, the proposed method can automatically identify differences in spatial features between the conditioning well data and the samples of the training image. Hence, it effectively resolves the difficulty of spatial matching between discrete datapoints and grid structures. We demonstrated the applicability of our model via 2D and 3D training image selection examples. The proposed methods effectively selected the appropriate TI, and then the pretreatment techniques for improving the accuracy of continuous TI selection were achieved. Moreover, the proposed method was successfully applied to training image selection of a discrete fracture network model. Finally, sensitivity analysis was carried out to show that sufficient conditioning data volume can reduce the uncertainty of the optimization results. By comparing with the improved MDevD method, the advantages of the new method are verified in terms of efficiency and reliability.
Modular multilevel converter (MMC) is considered as a promising topology for voltage-source converter (VSC) high-voltage, direct current (HVDC) applications. This paper presents a new control ...strategy for MMC-HVDC under unbalanced grid conditions. First, a new inner loop current control strategy based on nonideal proportional resonant (PR) controllers in stationary αβ frame is designed, which is more concise compared to the existing dual sequence current control scheme. Second, an analytical expression for circulating current is obtained which shows that the circulating currents will be asymmetric under unbalanced grid conditions and can be decomposed into positive-, negative-, and zero-sequence component. In order to suppress all these components, a new circulating current suppressing strategy is analyzed and designed also based on nonideal PR controllers. Application of nonideal PR controllers makes the control system well adapt to the fluctuation of grid frequency. The effectiveness of the proposed control strategy is verified through a simulation case of a 251-level MMC-HVDC transmission system using real-time digital simulator.
With the dramatically increasing deployment of the Internet of Things (IoT), remote monitoring of health data to achieve intelligent healthcare has received great attention recently. However, due to ...the limited computing power and storage capacity of IoT devices, users' health data are generally stored in a centralized third party, such as the hospital database or cloud, and make users lose control of their health data, which can easily result in privacy leakage and single-point bottleneck. In this paper, we propose Healthchain, a large-scale health data privacy preserving scheme based on blockchain technology, where health data are encrypted to conduct fine-grained access control. Specifically, users can effectively revoke or add authorized doctors by leveraging user transactions for key management. Furthermore, by introducing Healthchain, both IoT data and doctor diagnosis cannot be deleted or tampered with so as to avoid medical disputes. Security analysis and experimental results show that the proposed Healthchain is applicable for smart healthcare system.
The type II clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 system (CRISPR/Cas9) has been successfully applied to edit target genes in multiple plant species. ...However, it remains unknown whether this system can be used for genome editing in grape. In this study, we described genome editing and targeted gene mutation in 'Chardonnay' suspension cells and plants via the CRISPR/Cas9 system. Two single guide RNAs (sgRNAs) were designed to target distinct sites of the L-idonate dehydrogenase gene (IdnDH). CEL I endonuclease assay and sequencing results revealed the expected indel mutations at the target site, and a mutation frequency of 100% was observed in the transgenic cell mass (CM) as well as corresponding regenerated plants with expression of sgRNA1/Cas9. The majority of the detected mutations in transgenic CM were 1-bp insertions, followed by 1- to 3-nucleotide deletions. Off-target activities were also evaluated by sequencing the potential off-target sites, and no obvious off-target events were detected. Our results demonstrated that the CRISPR/Cas9 system is an efficient and specific tool for precise genome editing in grape.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Dynamic disturbance such as blasting may significantly affect the creep of rock. Quantification of the influence of dynamic disturbance on the creep behavior of rock is a prerequisite to the ...understanding of the long-term behavior of rock around excavations. In this study, a new creep-impact test machine that is capable of testing the rock failure behavior under combined creep loading and dynamic disturbance was introduced. We performed creep experiments on sandstone while a dynamic disturbance was applied. Axial strain, volumetric strain and acoustic emission (AE) events were measured. The results from the creep-impact experiment show that the rock creep was greatly affected by the dynamic disturbance. Dynamic disturbance may introduce further damage on rock and shorten the time-to-failure of creeping rock specimens. Combination of creep stress and dynamic disturbance resulted in two failure conditions: failure along with accelerating creep and failure during dynamic disturbance. If the dynamic disturbance was not followed by failure, the axial strain consisted of an instantaneous response as the dynamic disturbance was applied, followed by a primary phase of decelerating creep and a steady-state creep phase. This pattern was repeated after the next dynamic disturbance until the last dynamic disturbance that led to the failure. The creep resulted from micro-fracturing in the rock, which can be characterized by the cumulative AE energy if the AE events were monitored during the creep-impact test of rock. The creep behavior was more sensitive to dynamic disturbance under higher creep stress. Under the same creep stress, a dynamic disturbance with higher impact energy resulted in a higher axial strain rate, absolute volumetric strain rate and AE energy rate. Dynamic disturbance not only increased the axial strain rate but also promoted the dilatancy of the rock specimens. The failure of the rock specimens was mostly in the shear mode, and this failure pattern was merely affected by the dynamic disturbance, even though the specimens became more fragmented under the higher creep stress and higher impact energy.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A new modeling method is proposed to address the shortcomings of conventional geological modeling methods in simultaneously characterizing the geometry, stacking patterns, and well data of the ...channel bar in braided river. The channel bar model is reconstructed based on the target body, which is defined by the channel bar's geometric parameters points, lines, and surfaces. In the simulation process, the distributions of sandstone and mudstone are simulated first. Then, the channel bars at the well are simulated based on the channel bars identified on the well and the thickness of the sandstone, the priori geometries, and sizes of the channel bars. It is judged whether the proportion of the simulated channel bars has reached the global proportion. If not, a randomly selected point between wells is used as a virtual well, and the sandstone thickness is used to determine whether it is a single or composite channel bar. The process is repeated until the proportion of channel bars reaches the set proportion. Take the N gas field as an example. The analysis of the geometry, variance function, thickness distribution histogram, and volume distribution histogram of the simulation results shows that the new method can better characterize the channel bar's geometry, sizes, and stacking patterns than the multipoint geostatistical modeling method Snesim.
The Microprocessor complex, consisting of an RNase III DROSHA and the DGCR8 dimer, cleaves primary microRNA transcripts (pri-miRNAs) to initiate microRNA (miRNA) maturation. Pri-miRNAs are stem-loop ...RNAs, and ∼79% of them contain at least one of the three major and conserved RNA motifs, UG, UGU, and CNNC. We recently demonstrated that the basal UG and apical UGU motifs of pri-miRNAs interact with DROSHA and DGCR8, respectively. They help orient Microprocessor on pri-miRNA in a proper direction in which DROSHA and DGCR8 localize to the basal and apical pri-miRNA junctions, respectively. In addition, CNNC, located at ∼17 nucleotides (nt) from the Microprocessor cleavage site, interacts with SRSF3 (SRp20) to stimulate Microprocessor to process pri-miRNAs. The mechanism underlying this stimulation, however, is unknown. In this study, we discovered that SRSF3 recruits DROSHA to the basal junction in a CNNC-dependent manner, thereby enhancing Microprocessor activity. Furthermore, by generating various pri-miRNA substrates containing CNNC at different locations, we demonstrated that such stimulation only occurs when CNNC is located at ∼17 nt from the Microprocessor cleavage site. Our findings reveal the molecular mechanism of SRSF3 in pri-miRNA processing and support the previously proposed explanation for the highly conserved position of CNNC in SRSF3-enhanced pri-miRNA processing.
The decay-like fracture is an emerging mode of abnormal mechanical failure of composite insulators the study of which is still in its infancy. The degradation of epoxy resin of glass fiber reinforced ...polymer (GFRP) rod caused by discharge and current distinguish the decay-like fracture from both normal mechanical fracture and brittle fracture. In the present work, the detailed degradation of epoxy resin of GFRP rod in the decay-like fracture of composite insulator were examined using scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that the generation, expansion and release of pyrolysis gas is responsible for the formation of the bubbles and holes in the epoxy resin and the initial formation of holes in the silicone rubber housing during the degradation process. The erosion and pyrolyzation of epoxy resin results in mass loss of epoxy resin leading to degradation of the GFRP rod. High resolution XPS spectra of C1s and N 1s in GFRP rod reflects that oxidization process, exposure of glass fiber, and the introduction of nitrogen-containing compounds occurs during the degradation process. Microscopic photographs to explain the degradation of the epoxy resin and the initial formation of puncture holes in the silicone rubber housing are proposed based on the experimental results.
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