•A semi-analytical model for transient flow analysis with the capture of dynamic fracture behavior under long-term pumping rate conditions is developed in this four-zone fractured aquifer system.•The ...transformation in Laplace domain with predetermined time discretization and synchronous iteration techniques are deployed to obtain the solutions of pressure and pumping rate.•The typical features of fracture closure can be identified and the effect dynamic fracture behavior on pressure and pumping rate has been analyzed.
A robust and generic semi-analytical model with the capture of dynamic fracture behaviors under long-term pumping rate condition is developed for transient flow analysis in this four-zone system. To characterize the variations of fracture length, the improved pressure-dependent dynamic fracture factor is introduced and incorporated into this model. The Laplace domain with predetermined time discretization and synchronous iteration technique are deployed to obtain the solutions of pressure and pumping rate with the least computational burden. Meanwhile, the stability and convergence of this semi-analytical model can be met within the discrete time. Furthermore, the pressure and pumping rate solutions of this model under the static fracture condition are in good agreement with those of the constant length fracture, which verifies the reliability of this model.
The dynamic fracture model with the four -zone system develops five flow stages on the dimensionless pressure and its derivative curves: fracture bilinear flow, dynamic fracture flow, inner area linear flow, transitional flow and boundary-dominated flow. The dynamic fracture behavior is mainly reflected in the obviously positive upwards and pressure derivative curve presents a higher than unit slope. Moreover, the significant decrease of flow rate indicates that fracture closure could result in a rapid decline in pumping rate, which might be the reason why the pumping rate decrease quickly during the long-term pumping period. As the shrinkage coefficient increases, fractures are closed from abruptly to gradually, and typical signatures of fracture closure may be hidden if the shrinkage factor is too small, which may be caused by the instantaneous pressure depletion in the fractures. With the decrease of retained fracture coefficient, there is greater in the positive upward of transient pressure behavior and a lower in pumping rate. As a result, the flow rate will be seriously overestimated if the fracture closure is not considered especially for the tight formation.
Water injection is often used to supply formation energy in low permeability reservoirs. A lot of field data shows that fractures nearby the wellbores may extend hundreds of meters because of the ...poor injectability which is called water-induced fractures. The presence of these fractures significantly changes the flow of injected water thus affecting the development effects. However, few studies of reservoir numerical simulation methods have been presented to simulate the dynamic changes of fractures in the long-term waterflooding process. This study is based on the embedded discrete fracture model (EDFM) in which the fracture system has less dependence on the grid system. By improving the preprocessing algorithm, fracture growth can be considered in EDFM which is called the dynamic embedded discrete model (dEDFM). This new method provides an innovative idea for fracture propagation simulation by attaching new fracture elements to the original fractures once the failure criterion is satisfied. Meanwhile, there is no need to calculate the stress field once the in situ stress is provided, so the computational efficiency is greatly improved compared with the fluid-solid coupling method. Besides, dEDFM has a flexible way of handling fracture elements, so it is suitable for water-induced fracture simulation. Results show that fracture propagation speed is significantly influenced by matrix permeability, in situ stress, and injection intensity, and if the water-induced fractures propagate faster than the original waterfront movement velocity, changing law of the water content rate rising of production wells in different directions will be different. The contribution of this work lies in that it provides a suitable and efficient way for reservoir engineers to deal with water-induced fractures since the propagation of fractures can be considered when it comes to reservoir numerical simulation, and it is helpful for production data prediction and development adjustment in low permeability reservoirs.
Large-scale genotyping plays an important role in genetic association studies. It has provided new opportunities for gene discovery, especially when combined with high-throughput sequencing ...technologies. Here, we report an efficient solution for large-scale genotyping. We call it specific-locus amplified fragment sequencing (SLAF-seq). SLAF-seq technology has several distinguishing characteristics: i) deep sequencing to ensure genotyping accuracy; ii) reduced representation strategy to reduce sequencing costs; iii) pre-designed reduced representation scheme to optimize marker efficiency; and iv) double barcode system for large populations. In this study, we tested the efficiency of SLAF-seq on rice and soybean data. Both sets of results showed strong consistency between predicted and practical SLAFs and considerable genotyping accuracy. We also report the highest density genetic map yet created for any organism without a reference genome sequence, common carp in this case, using SLAF-seq data. We detected 50,530 high-quality SLAFs with 13,291 SNPs genotyped in 211 individual carp. The genetic map contained 5,885 markers with 0.68 cM intervals on average. A comparative genomics study between common carp genetic map and zebrafish genome sequence map showed high-quality SLAF-seq genotyping results. SLAF-seq provides a high-resolution strategy for large-scale genotyping and can be generally applicable to various species and populations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
By taking advantage of large changes in geometric and electronic structure during the reversible trans-cis isomerisation, azobenzene derivatives have been widely studied for potential applications in ...information processing and digital storage devices. Here we report an unusual discovery of unambiguous conductance switching upon light and electric field-induced isomerisation of azobenzene in a robust single-molecule electronic device for the first time. Both experimental and theoretical data consistently demonstrate that the azobenzene sidegroup serves as a viable chemical gate controlled by electric field, which efficiently modulates the energy difference of trans and cis forms as well as the energy barrier of isomerisation. In conjunction with photoinduced switching at low biases, these results afford a chemically-gateable, fully-reversible, two-mode, single-molecule transistor, offering a fresh perspective for creating future multifunctional single-molecule optoelectronic devices in a practical way.
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•Activation energy consists of two parts and both calculated by model free method and DMol3 approach.•Reaction path of the decomposition of Hg2Cl2 was described with one confirmed ...TS.•F2 as the dominant model was confirmed by model fitting method and Z(α) method.•Adsorption energy (Hg2Cl2 on activated carbon) decrease with the increase of temperature.•Microwave enhanced mercury desorption has a good HgCl2 extraction effect.
A novel microwave enhanced mercury desorption process was proposed for the regeneration of the spent activated carbon supported mercuric chloride catalysts. The mercury species desorption kinetics were investigated in detail by TG experiments, the overall apparent activation energy of 128.4 kJ/mol, the main reaction activation energy of 95.84 kJ/mol and the adsorption energy of 32.56 kJ/mol were confirmed with the combination of the model-free method and the DMol3 DFT module of Materials Studio package. The thermal desorption of HgCl2 and Hg2Cl2 were mainly between 473 K and 670 K, and the dominant mechanism for the desorption process was determined as second-order-model by the model-fitting method and the Z(α) master-plot method. Furthermore, the microwave enhancement degree of 26.36% was proved by the microwave heating experiment for the mercury desorption within 1500 s at 673 K, and the mercury content was significantly reduced from 19500 mg/kg to 149 mg/kg, which met the requirement of US land disposal restrictions (<260 mg/kg). Moreover, the preliminary activation of the spent activated carbon after microwave heating was demonstrated from the results of XRD, SEM and nitrogen adsorption analysis. Meanwhile, the HgCl2 solution with the concentration of 40–50 g/L could be effectively prepared by the water leaching of the condensate of mercury species, which could be used to regenerate the catalyst by soaking adsorption with activated carbon after microwave heating. Finally, a novel microwave enhanced mercury desorption process was proposed, which can synchronous realize the harmless and recovery of the spent activated carbon supported mercuric chloride catalysts.
Transposable elements (TEs) make up a majority of a typical eukaryote's genome, and contribute to cell heterogeneity in unclear ways. Single-cell sequencing technologies are powerful tools to explore ...cells, however analysis is typically gene-centric and TE expression has not been addressed. Here, we develop a single-cell TE processing pipeline, scTE, and report the expression of TEs in single cells in a range of biological contexts. Specific TE types are expressed in subpopulations of embryonic stem cells and are dynamically regulated during pluripotency reprogramming, differentiation, and embryogenesis. Unexpectedly, TEs are expressed in somatic cells, including human disease-specific TEs that are undetectable in bulk analyses. Finally, we apply scTE to single-cell ATAC-seq data, and demonstrate that scTE can discriminate cell type using chromatin accessibly of TEs alone. Overall, our results classify the dynamic patterns of TEs in single cells and their contributions to cell heterogeneity.
Formation of low-resistance metal contacts is the biggest challenge that masks the intrinsic exceptional electronic properties of two dimensional WSe2 devices. We present the first comparative study ...of the interfacial properties between monolayer/bilayer (ML/BL) WSe2 and Sc, Al, Ag, Au, Pd, and Pt contacts by using ab initio energy band calculations with inclusion of the spin-orbital coupling (SOC) effects and quantum transport simulations. The interlayer coupling tends to reduce both the electron and hole Schottky barrier heights (SBHs) and alters the polarity for the WSe2-Au contact, while the SOC chiefly reduces the hole SBH. In the absence of the SOC, the Pd contact has the smallest hole SBH. Dramatically, the Pt contact surpasses the Pd contact and becomes the p-type ohmic or quasi-ohmic contact with inclusion of the SOC. Therefore, p-type ohmic or quasi-ohmic contact exists in WSe2-metal interfaces. Our study provides a theoretical foundation for the selection of favorable metal electrodes in ML/BL WSe2 devices.
•A 3D-EDFM is proposed to efficiently simulate the mass and heat transfer of EGS.•A new analytical formula of fracture width variation with thermal stress for 3D-EDFM.•The mechanism and parameter ...sensitivity of the HDR development process are analyzed.
The successful utilization of hot dry rock is contingent upon the implementation of the development of the enhanced geothermal system (EGS) to create a complex fracture network.However, the fracture is affected by thermal stress, which results from the temperature difference between low-temperature fluid and high-temperature rock. To address this issue, a dynamic model of fracture width that takes thermal stress into account has been proposed. This model is based on the modified three-dimensional embedded discrete fracture model (EDFM) method and is solved by finite volume method coupling local boundary element.This model is based on the modified three-dimensional EDFM method and is solved by finite volume method coupling local boundary element. The proposed method has been validated through comparing with results obtained from commercial finite element software. Furthermore, the method is applied to the simulation of EGS to analyze the parameter sensitivity of the mass and heat transfer process. The results indicate that neglecting the impact of thermal stress on fracture width leads to an underestimation of produced energy. The shape and inclination angle of fractures significantly affect the mass and heat transfer in the reservoir.Moreover, the shape and inclination angle of fractures significantly affect the mass and heat transfer in the reservoir. A larger heat exchange area results in faster temperature decreases and increased heat energy production. High thermal diffusion coefficients improve the performance of EGS, while an increase in the thermal expansion coefficient of rock accelerates thermal breakthrough and enhances heat energy production. It has been found that maintaining a small pressure difference between injection and production and using low-temperature injection water can prolong the system lifetime and increase the final heat energy produced. This study presents an efficient numerical simulation method for mass and heat transfer in fractured reservoirs, expands the original EDFM method's application range and enhances calculation accuracy..
•The combustion characteristics of diesel in MAA at different injection pressures were investigated.•The inhibitory effect of methanol on diesel ignition was enhanced at high injection pressure.•Due ...to the addition of methanol, the peak values of AHRR were higher and the combustion durations became shorter.•The differences of FLoL between in AA and MAA became smaller with the combustion continuing.•The values of SINL and TINL were both lower in MAA than those in AA.
The experiments on the ignition and combustion characteristics of diesel in air atmosphere (AA) and premixed methanol/air mixture atmosphere (MAA) were conducted in a constant volume combustion chamber (CVCC) equipped with a high pressure common-rail injection system. The ignition and combustion processes were recorded by a high-speed camera and a combustion pressure acquisition system. Results show that with the increase of injection pressure from 40 to 160MPa, the flame lift-off length (FLoL) becomes longer; and the ignition delay is shortened from 2.80ms to 2.03ms (AA) and 2.90ms to 2.27ms (MAA) respectively; and correspondingly the combustion duration is shortened from 5.17ms to 2.47ms (AA) and 4.83ms to 2.13ms (MAA). Compared those in AA, the ignition delay is prolonged by 0.14ms on average, while the combustion duration is shortened by 0.27ms in MAA. At high injection pressure, the moments that the maximum combustion pressure occurs and the apparent heat release rates (AHRR) starts to rise are advanced; while in MAA both of them are delayed; and the peak value of AHRR increases. With the increase of injection pressure, both spatially integrated natural luminosity (SINL) and time integrated natural luminosity (TINL) reduce significantly, but the reduction trends of TINL weaken. Due to the addition of methanol, the FLoL of diesel becomes longer, and the SINL and TINL in MAA are both lower than those in AA.
Inference of relationships from whole-genome genetic data of a cohort is a crucial prerequisite for genome-wide association studies. Typically, relationships are inferred by computing the kinship ...coefficients (ϕ) and the genome-wide probability of zero IBD sharing (π0) among all pairs of individuals. Current leading methods are based on pairwise comparisons, which may not scale up to very large cohorts (e.g., sample size >1 million). Here, we propose an efficient relationship inference method, RAFFI. RAFFI leverages the efficient RaPID method to call IBD segments first, then estimate the ϕ and π0 from detected IBD segments. This inference is achieved by a data-driven approach that adjusts the estimation based on phasing quality and genotyping quality. Using simulations, we showed that RAFFI is robust against phasing/genotyping errors, admix events, and varying marker densities, and achieves higher accuracy compared to KING, the current leading method, especially for more distant relatives. When applied to the phased UK Biobank data with ~500K individuals, RAFFI is approximately 18 times faster than KING. We expect RAFFI will offer fast and accurate relatedness inference for even larger cohorts.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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