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In this paper, a pipeline leakage detection algorithm based on information fusion of pressure and flow is proposed, and its core work is the construction of BPA based on discount factors. The wavelet packet decomposition is carried out for the original signals, and the processed signals are used to train different SVM classifiers to achieve the first identification results. For the samples whose initial classification results are not completely consistent, BPA is calculated according to the confusion matrixes of the initial SVM classifiers. In this paper, static discount factors and dynamic discount factors are constructed using different methods, and dynamic discount factors are modified when decisions fail. Then comprehensive discount factors are constructed based on the combination of different static discount factors and dynamic discount factors. The Shafer discount rule is used to modify BPA. Finally, D-S evidence theory is used to fuse the BPA results of all classifiers under different discount combinations. Experiments show that this algorithm can effectively use the correlation of evidences to reasonably fuse the decision results of multiple sensors, overcome the problem that the accuracy of a single sensor is not high enough for leakage identification, and improve the identification accuracy of pipeline leakage.

The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system. The increasingly large and complex natural gas pipeline network requires more strictly on the calculation efficiency of transient simulation. To this end, this paper proposes a new method for the transient simulation of natural gas pipeline networks based on fracture-dimension-reduction algorithm. Firstly, a pipeline network model is abstracted into a station model, inter-station pipeline network model and connection node model. Secondly, the pressure at the connection node connecting the station and the inter-station pipeline network is used as the basic variable to solve the general solution of the flow rate at the connection node, reconstruct the simulation model of the inter-station pipeline network, and reduce the equation set dimension of the inter-station pipeline network model. Thirdly, the transient simulation model of the natural gas pipeline network system is constructed based on the reconstructed simulation model of the inter-station pipeline network. Finally, the calculation accuracy and efficiency of the proposed algorithm are compared and analyzed for the two working conditions of slow change of compressor speed and rapid shutdown of the compressor. And the following research results are obtained. First, the fracture-dimension-reduction algorithm has a high calculation accuracy, and the relative error of compressor outlet pressure and user pressure is less than 0.1%. Second, the calculation efficiency of the new fracture-dimension-reduction algorithm is high, and compared with the nonlinear equations solving method, the speed-up ratios under the two conditions are high up to 17.3 and 12.2 respectively. Third, the speed-up ratio of the fracture-dimension-reduction algorithm is linearly related to the equation set dimension of the transient simulation model of the pipeline network system. The larger the equation set dimension, the higher the speed-up ratio, which means the more complex the pipeline network model, the more remarkable the calculation speed-up effect. In conclusion, this new method improves the calculation speed while keeping the calculation accuracy, which is of great theoretical value and reference significance for improving the calculation efficiency of the transient simulation of complex natural gas pipeline network systems.

A new unloading contact model of an elastic–perfectly plastic half-space indented by an elastic spherical indenter is presented analytically. The recovered deformation of the elastic indenter and the indented half-space has been found to be dependent on the elastic modulus ratio after fully unloading. The recovered deformation of the indented half-space can be calculated based on the deformation of the purely elastic indenter. The unloading process is assumed to be entirely elastic, and then the relationship of contact force and indentation can be determined based on the solved recovered deformation and conforms to Hertzian-type. The model can accurately predict the residual indentation and residual curvature radius after fully unloading. Numerical simulations are performed to demonstrate the assumptions and the unloading model. The proposed unloading model can cover a wide range of indentations and material properties and is compared with existing unloading models. The cyclic behavior including loading and unloading can be predicted by combining the proposed unloading law with the existing contact loading model. The combined model can be employed for low-velocity impact and nanoindentation tests and the comparison results are in good agreement.

Summary: Warm ambient conditions induce thermomorphogenesis and affect plant growth and development. However, the chromatin regulatory mechanisms involved in thermomorphogenesis remain largely obscure. In this study, we show that the histone methylation readers MORF-related gene 1 and 2 (MRG1/2) are required to promote hypocotyl elongation in response to warm ambient conditions. A transcriptome sequencing analysis indicates that MRG1/2 and phytochrome interacting factor 4 (PIF4) coactivate a number of thermoresponsive genes, including YUCCA8, which encodes a rate-limiting enzyme in the auxin biosynthesis pathway. Additionally, MRG2 physically interacts with PIF4 to bind to thermoresponsive genes and enhances the H4K5 acetylation of the chromatin of target genes in a PIF4-dependent manner. Furthermore, MRG2 competes with phyB for binding to PIF4 and stabilizes PIF4 in planta. Our study indicates that MRG1/2 activate thermoresponsive genes by inducing histone acetylation and stabilizing PIF4 in Arabidopsis.

As the smart oilfield has grown, various deep learning technologies are being utilized to recognize the graphic feature of the indicator diagram in order to detect the fault type of rod pump system, so as to maintain the oilfield's regular production. However, the original data for the indicator diagrams from various oil fields are influenced by different geographic conditions, sensor equipment, acquisition software, etc. and exhibit specific environmental characteristics. This poses difficulties for indicator diagram-based fault diagnosis methodologies and necessitates the use of a more generalizable diagnosis model. To address the issue, a multi-feature fusion fault diagnostic model is proposed. The model fuses the Fourier descriptor of the indicator diagram as a feature with the graphic feature to enhance the robustness of the feature. Firstly, the two backbone networks perform feature extraction on the single-modal input data of their own networks. Secondly, the information from the indicator diagram and the Fourier descriptor are learned together as features through the interactive fusion module. And finally the integrated features are used for feature classification to obtain the output of the network. The accuracy of the diagnostic model when using only a single feature is respectively: 0.8233(the graphic feature), 0.9422(the Fourier descriptor feature) according to the findings of the validation experiment, and when using the fusion of the two features is 0.9724. The results demonstrate that the suggested multi-input feature fusion model performs better than the single-input model. The technique makes use of the correlation between the features to realize their complementary benefits and enhance the effectiveness of the diagnostic model.

While efficient removal of uremic toxins and accumulated water is pivotal for the well-being of dialysis patients, protein adsorption to the dialyzer membrane reduces the performance of a dialyzer. Hydrophilic membrane modification with polyvinylpyrrolidone (PVP) has been shown to reduce protein adsorption and to stabilize membrane permeability. In this study we compared middle molecule clearance and filtration performance of nine polysulfone-, polyethersulfone-, and cellulose-based dialyzers over time. Protein adsorption was simulated in recirculation experiments, while β2-microglobulin clearance as well as transmembrane pressure (TMP) and filtrate flow were determined over time. The results of this study showed that β2-microglobulin clearance (−7.2 mL/min/m2) and filtrate flow (−54.4 mL/min) decreased strongly during the first 30 min and slowly afterwards (−0.7 mL/min/m2 and −6.8 mL/min, respectively, for the next 30 min); the TMP increase (+37.2 mmHg and +8.6 mmHg, respectively) showed comparable kinetics. Across all tested dialyzers, the dialyzer with a hydrophilic modified membrane (FX CorAL) had the highest β2-microglobulin clearance after protein fouling and the most stable filtration characteristics. In conclusion, hydrophilic membrane modification with PVP stabilizes the removal capacity of middle molecules and filtration performance over time. Such dialyzers may have benefits during hemodiafiltration treatments which aim to achieve high exchange volumes.

Here the authors combine functional and structural work to show that METTL4 functions as U2 snRNA m6Am RNA methyltransferase supporting N6-methylation of 2’-O-methyladenosine in Arabidopsis.

Abstract Evaluating the accuracy of the satellite and reanalysis precipitation products is very important for understanding their uncertainties and potential applications. However, because of underestimation existing in commonly used evaluation benchmark, gauge precipitation data, it is necessary to investigate the influence of systematic errors in gauge data on the performance evaluation of satellite and reanalysis precipitation datasets. Daily satellite-based IMERG and model-based ERA5-Land, together with gauge precipitation data, were collected with the period from 2005 to 2016 over China in this study. Daily corrections for precipitation biases from wind-induced undercatch, wetting loss, and trace error were made for gauge measurements. A set of metrics, including relative bias, Kling-Gupta efficiency, frequency bias, and critical success index, were used to evaluate and intercompare the performances of IMERG and ERA5-Land against original and bias-corrected gauge data in different locations, years, seasons, climatic zones, classes of precipitation events, and precipitation phases. The results have shown that: After removing the bias in gauge data, the relative biases of IMERG and ERA5-Land both significantly decline. The noticeable changes of their accuracy occur and vary with different locations, years, seasons, climatic zones, and precipitation phases. Furthermore, the frequency biases of IMERG and ERA5-Land rise in no precipitation events and decline in light, moderate, heavy, and extreme precipitation events. The detection capability of IMERG and ERA5-Land in no and light precipitation events is also obviously affected. Therefore, this study has demonstrated the significant influence of systematic gauge precipitation errors on the assessment of IMERG and ERA5-Land and reinforces the necessity to remove negative bias in gauge data before using it as the benchmark.

This paper adopted theoretical derivation and experiments to investigate the stress wave propagation characteristics in rock under water jet impact and fracture response of coal. The evolution model of stress and displacement was presented to analyze the formation, propagation and attenuation of stress wave during rock fragmentation. The rock failure criterion for shear and tensile failure under dynamic impact loads, and crack propagation criterion under quasi-static pressure of water jet were established. And the broken pit range formed by shear component of stress wave and the damage range caused by tensile stress were obtained. Based on scanning electron microscopy and binarization method, experiments on water jet impinging coal under various velocities were conducted to study the failure patterns and fracture characteristics of coal. It is indicated that during the water-hammer pressure and its unloading stage, the radial stress and tangential stress decrease first and then increase, accompanying the occurrences of the radial and tangential tensile stresses peaks and the maximum compression displacement. In the subsequent stagnation pressure stage, the radial and tangential stresses trend to be the stable compressive stress and tensile stress, respectively. The peak values of radial stress and tangential stress at different stages all decay exponentially with the propagation distance. Moreover, the broken pit surrounded with radial and annular cracks is formed on coal when the jet velocity exceeds the threshold value, while the split fracture of coal will occur for the high impact velocity. The rock-breaking specific energy consumption decreases first and then increases with the increasing jet velocity. Besides, the theoretical damage scope is verified and close to the experimental value before the splitting fracture of coal. Combined with fracture morphology of coal debris with different sizes, two microscopic damage-failure modes of coal impacted by water jets are revealed, namely shear failure and tensile failure.

ObjectivePrimary adrenal malignant tumor is rare. The factors affecting the prognosis remain poorly defined. This study targeted to construct and corroborate a model for predicting the overall survival of adrenal malignant tumor patients.MethodsWe investigated the SEER database for patients with primary adrenal malignant tumor. 1,080 patients were divided into a construction cohort (n = 756) and a validation cohort (n = 324), randomly. The prognostic factors for overall survival were evaluated using univariate and multivariate Cox analyses. The nomogram was constructed and then validated with C-index, calibration curve, time-dependent ROC curve, and decision curve analysis in both cohorts. Then we divided the patients into 3 different risk groups according to the total points of the nomogram and analyzed their survival status by Kaplan-Meier curve with log-rank test.ResultsThe baseline characteristics of these two cohorts were not statistically different (P > 0.05). Using univariate and multivariate Cox analyses, 5 variables, including age, tumor size, histological type, tumor stage, and surgery of primary site, were distinguished as prognostic factors (P

Objective:To observe the effect of treatment of Chinese medicine fumigation and muscle energy technology, combined with family rehabilitation training by Jinyun rehabilitation platform on dysfunction improvement of patients with ankylosing spondylitis (AS), and explore a hospital-family integrated treatment approach that is feasible for dysfunction improvement of AS patients.Methods:A total of 80 AS patients with active stage who met the diagnostic and inclusion criteria were randomly assigned to the experimental group (n=42) and the control group (n=38). The control group was treated with Chinese medicine fumigation, muscle energy technology and anti-inflammatory painkillers. The treatment of Chinese medicine fumigation for AS patients was about 30 minutes each time, and the treatment of muscle energy technology was about 40 minutes each time. The frequency of the two kinds of treatment was once a day, five times a week, the first week of each month was chosed as the treatment time, and there should be six weeks of treatment time in six months. The anti-inflammatory painkiller was oral celecoxib, 200 mg each time, twice a day, and the treatment lasted for three weeks. The experimental group received the family rehabilitation training management of Jingyun rehabilitation platform on the base of the control group. The AS patients completed the action as prompted by the platform, then recorded a video to the platform; the rehabilitation therapists entered the backstage and checked the completion of the action; the AS patients could enter into next stage of clinical treatment and rehabilitation training when their movements were qualified. The family rehabilitation training was divided into two phases, in the first phase, the treatment time of three months lasted about 30 minutes each time, three times a day; in the second phase, the treatment time of three months lasted about 30 minutes each time, two times a day. After treatment, the visual analogue score (VAS), rang of motion (ROM), muscle strength, Bath AS disease activity index (BASDAI), Bath AS functional index (BASFI), Schober test score, erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) were compared between the two groups.Results:Before treatment, there was no significant difference in VAS, ROM, muscle strength, BASDAI, BASFI, Schober score, ESR and CRP between the two groups (P> 0.05). After treatment, the VAS, BASDAI, BASFI, ESR and CRP were decreased (P< 0.01), and the ROM, muscle strength and Schober score were increased in two groups compared with before treatment (P< 0.01). After treatment, the VAS, BASDAI, BASFI, ESR and CRP in the experimental group were lower than those of the control group (P< 0.05), and the cervical vertebrae ROM, lumbar vertebrae ROM, muscle strength and Schober score were higher than those of the control group (P< 0.05).Conclusion:Chinese medicine fumigation combined with muscle energy technology is effective for treating low back pain of AS patients. Under these treatments, adding Jingyun rehabilitation platform for family rehabilitation training can effectively improve the treatment effect of low back pain, promote the overall recovery of the patient's spinal function, and help the AS patients to achieve a hospital-family integrated treatment approach.

It has been reported that systematic bias exists in gauge measurements, which are usually used as the evaluation benchmark, so it is crucial to investigate the impacts of gauge data bias on the evaluation of satellite precipitation products. Six satellite precipitation products (IMERG, CMORPH, GSMaP, PERSIANN, PERSIANN−CCS, and PDIR−Now) and gauge data are collected from 2003 to 2015 in the arid region of Northwestern China. A daily correction for precipitation biases from wind-induced undercatch, wetting loss, and trace error is made for gauge measurements. The changes in metrics, including four continuous and four categorical metrics, are calculated to illustrate how the gauge data bias impacts the evaluation of six satellite precipitation products. The results show the following: The overall performances of six satellite precipitation products are undervalued by the gauge bias. Compared to other satellite products, the performance of IMERG is the best, whether before or after bias correction. However, the performances of all six satellite products are still not good enough even after bias correction and need to be improved. The impacts of gauge bias on the evaluation of the satellite precipitation products also differ by subregion, season, satellite precipitation product, precipitation intensity, and precipitation phase. In conclusion, the impacts of the gauge bias on the performance assessment of satellite products are obvious over the study region, implying that bias correction for gauge measurements is needed to obtain an accurate understanding of the performance of satellite precipitation products if choosing the gauge data as the evaluation benchmark.

With the reduction and depletion of shallow energy, the mining depth of coal around the world is increasing year by year, and the mining depth of some coal mines in China has reached kilometers. The main roadway near the goaf with the deep high static stress is very easy to be damaged after being disturbed by the mine earthquake. Taking the main roadway in the no. 1 mining area of Gaojiapu coal mine in Binchang mining area, Shaanxi Province, China, as the engineering background, the high-energy mine earthquake monitored by the on-site microseism is equivalently simulated through the dynamic module of FLAC3D, and the spatial-temporal rotation characteristics of the principal stress of roadway surrounding rock under the disturbance of mine earthquake are studied and analyzed and put forward corresponding prevention and control measures. Research shows early stage of mine earthquake disturbance, roadway roof is first affected, and the principal stress of the roof has the trend of deflection to the side of the goaf. In the middle stage of mine earthquake disturbance, the main body of roof principal stress deflects to the side of goaf, and the deflection range is large. In the later stage of mine earthquake disturbance, the principal stress directions in the surrounding rock reverse rotation, and the reverse rotation angle of the principal stress direction in the roof is the largest. Finally, the asymmetric distribution characteristics of principal stress rotation are verified by using the asymmetric deformation phenomenon on both sides of roadway surrounding rock. Based on the rotation characteristics of principal stress under the dual influence of mine earthquake disturbance and goaf, optimize the layout scheme and blasting parameters of blasting pressure relief holes. The transmission direction of principal stress can be changed by blasting pressure relief method; meanwhile, the transmission of principal stress can be blocked; through the comparison of microseismic activity law before and after pressure relief, pressure relief effect is good. The research results can provide a certain reference basis for coal mine roadway pressure relief and reducing disaster conditions.

Phase change energy storage is a new type of energy storage technology that can improve energy utilization and achieve high efficiency and energy savings. Phase change hysteresis affects the utilization effect of phase change energy storage, and the influencing factors are unknown. In this paper, a low-temperature eutectic phase change material, CaCl2·6H2O-MgCl2·6H2O, was selected as the research object, combined with the mechanism of phase change hysteresis characteristics, using a temperature acquisition instrument to draw the step cooling curve. A differential scanning calorimeter was used to measure the DSC (differential scanning calorimetry) curve, and the hysteresis characteristics of phase transformation were studied by factors, such as heat storage temperature, cooling temperature, and cooling rate. The experimental results show that when heating temperature increases by 30 °C, phase transition hysteresis decreases by about 3 °C. The cooling temperature decreased by 10 °C, and the phase transition hysteresis increased by 2.69 °C. This paper provides a new idea for optimizing the properties of phase change energy storage materials and provides a possibility for realizing the parametric control of phase change hysteresis factors.

For the quantitative recognition and characterization of the flow characteristics of polymorphism coalbed gas in tectonic coal, experiments on pore morphology, pore diameter distribution, and methane adsorption law in outburst tectonic coal were carried out by field emission scanning electron microscopy and low-field nuclear magnetic resonance. The results revealed abundant round and dense “pyrolysis pores” in outburst tectonic coals, most of which were adsorption and seepage pores, with micropores accounting for 78.2%. Most pores were independent and formed the network pore space for gas enrichment and migration in outburst tectonic coal. The transverse relaxation time (T2) of methane adsorption in tectonic coal and crushed outburst tectonic coals presented three peaks, namely, adsorption, drifting, and free peaks. The isolation of nanopores and micropores revealed lower adsorption capacity of outburst tectonic coal than that of crushed outburst tectonic coal. The gas staged adsorption of raw coal with outburst tectonic low-permeability was observed. Under low gas pressure, the T2 spectral peak area of methane adsorption increased remarkably, whereas that of desorbed methane increased slightly. As gas pressure was increased to a certain numerical value, the increment of methane adsorption decreased and tended to reach equilibrium. This finding reflected that methane adsorption tended to be saturated after gas pressure reached a certain value, but desorbed methane in isolated micropores increased quickly. The quantitative recognition and characterization of pore structure and gas adsorption in tectonic low-permeability outburst coal seams based on low-field magnetic resonance imaging provide an experimental method for gas exploitation in coal seams and the study and control of coal and gas outburst mechanism.

In this paper, the case of two adjacent frame structures is studied by establishing a mechanical model based on the transfer matrix method of multibody system (MS-TMM). The transfer matrices of the related elements and total transfer equation are deduced, combining with the Hertz-damp mode. The pounding process of two adjacent frame structures is calculated by compiling the relevant MATLAB program during severe ground motions. The results of the study indicate that the maximum error of the peak pounding forces and the peak displacements at the top of the frame structure obtained by the MS-TMM and ANSYS are 6.22% and 9.86%, respectively. Comparing the calculation time by ANSYS and MS-TMM, it shows that the computation efficiency increases obviously by using the MS-TMM. The pounding mainly occurs at the top of the short structure; meanwhile, multiple pounding at the same time may occur when the separation gap is small. The parametric investigation has led to the conclusion that the pounding force, the number of poundings, the moment of pounding, and the structural displacement are sensitive to the change of the seismic peak acceleration and the separation gap size.

In this study, Nd and As are mainly sealed into industrial pure Fe cylinders. The effect of different temperatures on the high-temperature interaction of an Nd−Fe−As ternary system is studied via X-ray diffraction, optical microscopy, and scanning electron microscopy after heat insulation for 30 h at 1173, 1223, and 1273 K. The results show that the common products under high-temperature interaction are NdAs, Fe17Nd2, and Fe. Fe12As5 is present at 1173 K, whereas Fe2As is produced at 1223 and 1273 K. The diffusion ability of Nd is weaker than that of As. Nd mainly diffuses through the Fe atomic vacancy mechanism. As mainly binds to Fe to form Fe and As compounds.