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This study introduces an innovative approach of utilizing ZnO nanorod growing technology to the sateen fabric in order to improve its ballistic performance. Through SEM, FTIR, XRD and XPS analyses, ZnO nanorods with majority length of 1000–1500 nm and fineness of 200–600 nm have been deposited on the surface of sateen fabric surface Compared the fabric with ZnO nanorods (S-11-Nrs) with its neat counterpart, the mechanical properties of S-11-Nrs are increased, especially the inter-filament friction and fabric tensile breaking strength. However, in the impact process, the number of filaments involved in the impact is reduced and the filaments are mainly failure by the shear action of the bullets. Due to these positive and negative effects, the energy absorption of S-11-Nrs displays inferior ballistic energy absorption. Nevertheless, at lower areal density, in the non-perforation test, S-11-Nrs presents less BFS and shows better resistance to the consecutive shotting process compared with the neat fabric. The reason is that the increase of inter-filament friction limits the movement of filaments and thus results in less BFS. In addition, the flexibility, air permeability and moisture permeability are still kept. This research offers valuable insights for the design and development of comfortable soft body armor.

In this paper, a new flexible stab-resistant composite material was prepared by growing ZnO nanowires on aramid plain fabric by the hydrothermal method. Through SEM, FTIR, and XRD characterization, it is proved that ZnO nanowires have been grown on aramid fabric and the surfaces of aramid filaments become much rougher. Moreover, the inter-filament friction and breaking strength of aramid fabric with nanowires are increased significantly, especially the inter-filament friction, which has been increased by more than 4 times after ZnO nanowires growth. Stab tests were conducted on the bare aramid fabric sample and aramid fabric sample with ZnO nanowires based on the test standard of GA 68–2019. Both of the two samples are 43 layers and are subject to 5 stabs of D1 knife, 3 stabs of D2 knife and 3 stabs of D3 knife. The stab resistance of aramid fabric grown with nanowires is significantly enhanced, and the average penetration depth under the D1 knife impact is decreased by 49.7%. The reason may be that the inter-filament friction increases dramatically with the nanowires and thus the friction energy consumption increases. The flexibility test results show that the softness characteristics of the single aramid fabric and the 43-layer fabric with the nanowires are still maintained. In addition, although the growth of nanowires will lead to smaller voids and a decrease of air permeability of the fabric, the moisture permeability has been slightly improved because ZnO nanowires have the ability to bind with water.

Predicting earthquakes through reasonable methods can significantly reduce the damage caused by secondary disasters such as tsunamis. Recently, machine learning (ML) approaches have been employed to predict laboratory earthquakes using stick-slip dynamics data obtained from sheared granular fault experiments. Here, we adopt the combined finite-discrete element method (FDEM) to simulate a two-dimensional sheared granular fault system, from which abundant fault dynamics data (i.e., displacement and velocity) during stick-slip cycles are collected at 2203 “sensor” points densely placed along and inside the gouge. We use the simulated data to train LightGBM (Light Gradient Boosting Machine) models and predict the gouge-plate friction coefficient (an indicator of stick-slips and the friction state of the fault). To optimize the data, we build the importance ranking of input features and select those with top feature importance for prediction. We then use the optimized data and their statistics for training and finally reach a LightGBM model with an acceptable prediction accuracy (R2 = 0.94). The SHAP (SHapley Additive exPlanations) values of input features are also calculated to quantify their contributions to the prediction. We show that when sufficient fault dynamics data are available, LightGBM, together with the SHAP value approach, is capable of accurately predicting the friction state of laboratory faults and can also help pinpoint the most critical input features for laboratory earthquake prediction. This work may shed light on natural earthquake prediction and open new possibilities to explore useful earthquake precursors using artificial intelligence.

This paper introduces a nonlinear, magnetically charged, singularity-free black hole model. The Ricci scalar, Kretschmann scalar, horizon, energy conditions, and Hawking radiation corresponding to the singularity-free metric are presented, and the asymptotic behavior and quantum correction of the model are examined. The model was constructed by coupling a mass function with the regular black hole solution under nonlinear electrodynamics in general relativity. Aside from resolving the problem of singularities in Einstein’s theory of general relativity, the model asymptotically meets the quantum correction under an effective field theory. This obviates the need for additional correction terms; in this regard, the model outperforms the black hole models developed by Bardeen and Hayward. Regarding the nonlinear magnetic monopole source of the gravitational field of the black hole, the energy–momentum tensors fulfill weak energy conditions. The model constitutes a novel, spherically symmetric solution to regular black holes.

In this study, ZnO nanoparticles were prepared by a hydrothermal method with varying the reaction times, material ratios and reaction temperatures. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD) and Fourier infrared spectroscopy (FTIR). It was shown that the material ratio significantly affected the structure and morphology of the synthesized ZnO nanoparticles, and then the uneven nano-octahedral structure, uniform nano-octahedral structure, nano-tubular structure, and nano-sheet structure could be obtained successively. The synthesized ZnO nanoparticles as mordant were used for the dyeing of silk fabrics with different natural dyes (tea polyphenols and hematoxylin). Moreover, they could improve the dyeing properties and fastness (wash and light) on silk fabrics to a certain extent.

BackgroundBased on 122 cases reported in China, data mining indicated that Sini Powder (SNP) and the Zuojin Pill (ZJP) are both widely used as the basic recipe for treating Gastroesophageal Reflux Disease (GERD).ObjectivesTo evaluate the intervention effects of Sini Zuojin Decoction (SNZJD) in patients with GERD.MethodsA comprehensive collection of randomized controlled trials (RCTs) using SNZJD in patients with GERD that were published in domestic and foreign journals was made by computer retrieval. RevMan 5.3 software was used for meta-analysis and bias risk assessment, Stata 14.0 software was used for sensitivity analysis, GRADE profiler 3.6 was used to evaluate the level of evidence, and trial sequential analysis (TSA), employed to control for random errors, was performed to assess the main outcomes. Network pharmacology analysis was applied to preliminarily study the mechanisms of action of SNZJD on GERD.ResultsThirteen articles were eventually included, covering a total of 966 patients. Meta-analysis indicated that: ① the SNZJD plus traditional stomach medicines (SPTSM) group was more effective than the traditional stomach medicines (TSM) group (RR = 1.16, 95% CI [1.04, 1.29], P = 0.009); ② the experimental group with SNZJD was significantly better than TSM controls in improving heartburn, substernal chest pain, acid regurgitation, and food regurgitation symptoms (P < 0.0001); ③ SPTSM could significantly decrease total symptom scores with substantial effectiveness (P < 0.00001). The recurrence rate and adverse effects of SNZJD treatment were significantly reduced (P < 0.05). TSA showed that the effective rate of meta-analysis might be reliable, but the recurrence and safety results were still uncertain. According to the evaluation by the GRADE method, the quality of evidence was low. Besides, SNZJD might treat GERD by acting on related targets and pathways such as inflammation, hormone regulation, and so on.ConclusionsSNZJD might be useful in the treatment of GERD, but its long-term effects and specific clinical mechanisms are unclear. Due to the poor quality of the evidence, more samples and high-quality clinical studies should be tested and verified in the future.

Tight sand gas is an important unconventional natural gas. Liquid filtration plays a main role in the formation damage. Flowback rate is closely related to the formation permeability recovery. Usually, the more flowback rate is, the better the permeability recovery is. In order to research the factors that influence the liquid flowback, the tight sand characteristics and gas displacement have been investigated. Some experiments were carried out, including porosity, permeability, XRD, casting thin section, SEM, stress sensitivity, rock expansion, and gas displacement. The results are shown as follows. Taiyuan formation has average high clay content than H8 formation. Illite is the main clay in Taiyuan formation; chlorite is the main clay in H8 formation. From the casting thin section, the rock has strong compression. Taiyuan formation has large pore. However, H8 formation mainly has small cracks. Through the SEM, there are many micro- to nanocracks as well as some pores in these two formations. In some cases, cracks penetrate the clays. From the permeability stress sensitivity, these tight sands have strong stress sensitivity. Permeability decreases quickly with increasing confining pressure. In the rock expansion experiment, the tight sand has less expansion rate compared with shale gas rock and volcanic gas rock. Rock expansion rate has positive relationship with clay content. In the gas displacement experiment, usually the higher the clay content, the lesser the liquid flowback. Some samples have high clay content. However, it has high flowback rate, which may account for good pore connection. Through the above study, the flowback rate has negative relationship with clay content and positive relationship with pore size, pore connection, and displacement pressure. In order to increase tight gas production in the study area, the formation should have high flowback rate and less liquid retention. Therefore, clay expansion preventing additives should be added into the fracturing liquid to reduce the liquid retention. The quick flowback should be implemented after hydraulic fracturing for reducing the interaction between liquid and rock. At the same time, the drawdown pressure should keep in a certain value to reduce stress sensitivity.

The importance of inter-yarn friction to ballistic fabric has been widely investigated. However, the couple effects of inter-yarn friction, fabric structure and number of layers have not been explored. Therefore, this paper put forward to investigate the ballistic performance of multi-layer fabric panels with different weave structure and inter-yarn friction. Three different structures (plain, sateen and UD-like), various number of layer (1-layer, 4-layer, 8-layer and 12-layer) and three levels of coefficients of friction were considered and their effects on the ballistic performance will be discussed through finite element (FE) method. The impact velocity is set as 475 m/s and the projectile is a 1 g steel flat cylinder with both the diameter and height of 5.5 mm. It has been found that the sateen fabric structure with 12-layer and higher coefficients of friction firstly reduces the projectile velocity to zero, while the corresponding plain structure and the UD-like structure reduce the projectile velocity to 125 m/s and 200 m/s individually, which indicates that when the number of layer and coefficients of friction are both much larger, the sateen fabric shows the best ballistic performance among the three structures. The reasons behind are as following. As far as the structure concerned, sateen structure has more interlacements than UD-like fabric and more straight sections than plain fabric. In addition, at higher coefficients of friction, this structure enables higher stress distribute in more layers and in larger areas than plain fabric and UD-like fabric and give rise to a layer-by-layer fracture but not fracture simultaneously. [ABSTRACT FROM AUTHOR]