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With the rapid development of traditional Chinese medicine (TCM) industry, the treatment of TCM wastewater has become an important environmental issue. Among them, TCM processing cleaning wastewater is suitable for recovering high-quality water resources from it due to its low chemical oxygen demand (COD). Compared with pressure driven membrane process, Membrane distillation (MD) can yield highly purified distillate under mild operating conditions. Therefore, this work aims to evaluate the effects of feed temperature, feed flow, osmotic side vacuum degree and membrane material on the treatment of cleaning wastewater from TCM processing. Besides, the fouling of membrane in MD process and the efficiency of chemical cleaning on fouling removal were also investigated. The results show that it is feasible to recover high-quality water from traditional Chinese medicine processing cleaning wastewater by VMD. Compared with feed, COD in permeate decreased by 99%. During the 10 h experiment, the flux of both membranes decreased slightly due to the accumulation of fouling layer on the membrane surface. Chemical cleaning, especially alkali as cleaning agent can effectively remove the fouling layer. [Display omitted] • VMD can recover high quality water from the cleaning wastewater of traditional Chinese medicine processing. • The flux and thermal efficiency were significantly affected by temperature and vacuum. • The flux decrease occurred due to the formation of fouling layer. • Contact angle and rejection recovery of contaminated membranes can be achieved by NaOH cleaning. • PTFE membranes are more suitable than PVDF ones for long-term operation due to higher flux and anti wetting ability. [ABSTRACT FROM AUTHOR]

• Dust suppression materials are prepared by modifying soy protein isolate. • Dust suppressant effectively controls dust pollution in open cut coal mines. • Optimization of preparation of dust suppressant by response surface methodology. To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmentally friendly soy protein isolate with methyl methacrylate. This dust suppressant could effectively control dust pollution in open cut coal mines. The optimized conditions for graft copolymerization in this case were determined by a response surface experiment designed with Design-Expert 10 software. Characterization by scanning electron microscopy showed a significant morphology change of the dust suppressant and the generation of a rigid and dense layer on its surface after interacting with coal dust. The layer exhibited good bonding and dust suppression performance. The analysis with Fourier-transform infrared spectroscopy revealed the appearance of new absorption peaks near 1300, 1072, and 1631 cm−1, demonstrating effective graft copolymerization. The proposed dust suppressant exhibited excellent wind erosion resistance, with a resistance that exceeded 90% at a wind speed of 6.5 m/sec. The successful graft copolymerization and effective bonding and curing of the dust suppressant on coal dust were experimentally verified. This is of great significance to the control of coal dust pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Ultrasonic inspection is an environmentally friendly and easily deployable nondestructive testing (NDT) method widely used for defect detection of critical components in the industry. Phased array ultrasonic testing (PAUT) is one of the most advanced ultrasonic inspection methods, which gives volume inspection with increased resolution and coverage, improving inspection efficiency. Because of the weld structure echoes and the abstract nature of ultrasound images, especially facing meters and feature-changing weld joints with different thicknesses and welding methods in shipbuilding, the analysis of the PAUT weld data still relies on experienced rater random inspections. Rating complex welded products process is lengthy, costly, and prone to introduce human error during the manual rating but challenges automatic detection. To automatically segment defects in PAUT data, this work shows a combination of PAUT data of ship weld and three-dimensional (3D) U-net architecture. Combining PAUT imaging principles with welding and scan processes, a PAUT volumetric image dataset, including different thicknesses and scan angles, is established. We pioneered the application of 3D U-net architecture to segment defects in PAUT volume data. We found that U-net architecture with two encoding stages will perform better in segmenting defects in PAUT data, and region-based loss mainly improves the accuracy. Furthermore, a lightweight U-net architecture containing skip-connection and residual blocks is proposed with precision and efficiency improvement. The validation results show that the proposed U-net architecture offers a feasible solution to the problem of segmenting defects from PAUT data with a Dice accuracy of 90.9 %. Segmentation results help to locate and measure defects. This method makes locating and sizing defects in PAUT weld data possible within a fraction of a second. [ABSTRACT FROM AUTHOR]

• A new environmental protection gelling scheme was proposed and tested. • PVA, SA, TE and HB constitute a double crosslinked gel to improve stability. • Gel time is controllable, with high water retention and super-absorbency. • The addition of shell powder to the gel increases the flame-retardant effect. • Both low-temperature and high-temperature have good inhibition effect. In order to solve the problem of spontaneous combustion of coal in mined-out areas, a new type of P/S/T/H environmentally friendly hydrogel was designed by using polyvinyl alcohol, sodium alginate and di(triethanolamine) titanate diisopropyl to form a gel system and adding the environmentally friendly material hybrid shell bio-filler. The formulation of P/S/T/H gel was studied by orthogonal experiment, and the forming time was precisely controlled. The synthesis mechanism and flame-retardant properties of the gels were investigated by various experimental methods. The results show that: There are folds and three-dimensional pore structures inside the P/S/T/H gels, and the two cross-linked networks strengthen the stability of the gels. Compared with WG gel and single cross-linked network gel, P/S/T/H gel has the best water retention, water absorption/salt resistance and flame-retardant effect. The water retention rate of P/S/T/H gel is still as high as 20% after 12 h, the water-absorbing multiplicity is more than 400 after 90 min, and the salt-resistant multiplicity is 54 after 90 min. When P/S/T/H gel is added to the coal samples, the combustion end temperature lags 8.4 °C, the heat release is reduced by 19.9%, the average CO inhibition rate is 45.9%, the maximum heat release rate is reduced by 20.1 KW/m2, the total heat release rate is reduced by 36.6%, and the maximum flue gas inhibition rate is 87.1%. Therefore, the highly efficient and environmentally friendly P/S/T/H gel is expected to play an important role in the work of fire prevention in mined-out areas. [ABSTRACT FROM AUTHOR]

• The mechanism of gas phase reaction inhibition of coal dust combustion was revealed. • The changes of free radicals and intermediate substances were quantitatively analyzed. • NaHCO 3 and MPP show different patterns of inhibition and dominance. • HPO 3 ⇔ PO 2 is the central radical reaction that interrupts the combustion chain. In this paper, the flame propagation behavior and free radical reaction mechanism of two powder explosive suppressants, sodium bicarbonate (NaHCO 3) and polyphosphate melamine (MPP), at different additions were investigated using Hartmann experimental system and CHEMKIN-PRO numerical simulation. The results showed that NaHCO 3 and MPP showed different inhibitory advantages. MPP mainly suppressed the propagation of flame during the development and rapid rise stages, while NaHCO 3 had a better suppression effect at the preliminary stage of explosion. The gas phase kinetic analysis also proved that the NaHCO 3 reaction was rapid, and it could decompose and endothermy at the beginning of the explosion, and generate gaseous H 2 O and CO 2 to dilute the concentration of volatile components. Meanwhile, NaOH, NaO, and NaO 2 produced by decomposition consumed free radicals and reduced the initial reaction rate of the explosion. In the process of gas phase reaction, MPP continuously reduced the amount of flame free radicals through a inhibition cycle of HPO 3 ⇔ PO 2 , and generated a large number of inert products for inerting fixed carbon, exhibiting better long-term effectiveness. This study can provide a reference for the selection and design of explosion suppressants. [ABSTRACT FROM AUTHOR]

The Green materials zinc borate (ZB) and zinc silicate (ZS) were adopted as suppressants. Hartmann tube was used to study the flame inhibition effect of oil shale explosion. It showed that the flame front length became shorter and the propagation velocity and acceleration gradually decreased by increasing suppressants. When 30 wt% ZB was added, the complete inhibition of oil shale explosion flame could be achieved, while the flame inhibition effect of ZS was relatively weak. Flynn-Wall-Ozawa and Starink methods were used to study the activation energy of oil shale, which showed that the activation energy increased significantly after adding the suppressant. By characterization tests, the microstructure changes of oil shale before and after the explosion were analyzed, and the mechanism of the explosion inhibition difference between two suppressants was revealed. ZS played a physical inhibiting role by absorbing heat, reducing temperature and diluting the concentration of combustible gases. While ZB not only had the physical inhibition role of absorbing heat and diluting the concentration of gases, but also had a covering physical inhibition role. Simultaneously, ZB also had the chemical effect. It played a highly effective physical and chemical synergistic inhibition role in the deflagration of oil shale. • Zinc borate and zinc silicate were firstly applied in oil shale flame suppression. • Zinc borate has the better inhibition effect than zinc silicate. • The pyrolysis behavior of oil shale was studied thermodynamically. • The physical and chemical synergistic suppression mechanism of ZB was proposed. [ABSTRACT FROM AUTHOR]

Conductive hydrogels have attracted widespread attention because of their integrated characteristics of being stretchable, deformable, adhesive, self-healable, and conductive. Herein, we report a highly conductive and tough double-network hydrogel based on a double cross-linked polyacrylamide (PAAM) and sodium alginate (SA) network with conducting polypyrrole nanospheres (PPy NSs) uniformly distributed in the network (PAAM-SA-PPy NSs). SA was employed as a soft template for synthesis of PPy NSs and distribution of PPy NSs uniformly in the hydrogel matrix to construct SA-PPy conductive network. The PAAM-SA-PPy NS hydrogel exhibited both high electrical conductivity (6.44 S/m) and excellent mechanical properties (tensile strength of 560 kPa at 870 %), as along as high toughness, high biocompatibility, good self-healing and adhesion properties. The assembled strain sensors showed high sensitivity and a wide sensing range (a gauge factor of 1.89 for 0–400 % strain and 4.53 for 400–800 % strain, respectively), as well as fast responsiveness and reliable stability. When used as a wearable strain sensor, it was able to monitor a series of physical signals from human large-scale joint motions and subtle muscle movements. This work provides a new strategy for the development of electronic skins and flexible strain sensors. [Display omitted] [ABSTRACT FROM AUTHOR]

Objective This study aimed to summarize the clinical characteristics of Rosai-Dorfman disease primarily involving the central nervous system and to explore diagnosis and treatment. Methods We analyzed the clinical, imaging, and pathologic characteristics; treatment; and prognosis in 3 cases of Rosai-Dorfman disease primarily involving the central nervous system. We also performed a literature review. Results The largest of multiple intracranial lesions was totally resected, and steroid administration and radiotherapy were performed in phases for the remaining lesions. During the 1-year follow-up period, the excised lesion did not recur, and no obvious variations were observed in the other lesions. Subtotal resection was performed of the largest of another group of multiple intracranial lesions, and the residual did not show any obvious variations during the 1-year follow-up period. The isolated lesion was totally resected and did not recur during a 2-year follow-up period. Conclusions Rosai-Dorfman disease with multiple lesions primarily involving the central nervous system is rare. Imaging characteristics are similar to meningiomas, and the pathological features include lymphocytes and plasma cells reaching tissue cells with large volume and abundant cytoplasm. Surgery is the preferred treatment, as the effects of steroid administration and radiotherapy are not apparent. [ABSTRACT FROM AUTHOR]

Ensuring the high-quality construction of the ST Railway is a top priority for construction organizers and managers. In this paper, a stepwise approach combining bounding box (BB) technology and the Gilbert–Johnson–Keerthi (GJK) algorithm was proposed to determine the intersections between fractures. With the use of a stepwise approach, most of the nonintersecting fracture pairs were excluded, the computed speed and effectiveness were greatly improved compared with those in previous studies, and the length and direction vectors of the fracture intersections were obtained. A 3D discrete fracture network (DFN) model was generated and validated according to fracture data acquired from the right bank slope of the Nujiang Grand Bridge (NGB) of the ST Railway by unmanned aerial vehicle (UAV) photogrammetry technique. Based on the DFN model, the stepwise approach was implemented for intersection analysis and connectivity analysis. Connectivity parameters, including the number of intersections per unit volume and the intersection length per unit volume, were calculated as 1.279 m-3 and 2.296 m-2, respectively. The intersection analysis suggested that the mean length of the intersections was 1.796 m, and fracture sets 2 and 3 constituted the main flow pathways and played a predominantly combined cutting role for the rock masses in the study area. In addition, the investigation of the direction vector of the intersections indicated that the combined cutting action of fracture sets 2 and 3 easily formed wedge-shaped failure surfaces, and the lateral expansion produced by bedrock fracture groundwater was also unfavourable to the stability of the slope. • A stepwise approach combining BB technology and the GJK algorithm was proposed. • A 3D DFN model was generated based on fracture data obtained by UAV photogrammetry. • The hydraulics and stability of the rock mass in the rock slope were investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] The properties of a green waste molecular sieve-based powder suppressor in inhibiting the flame propagation of coal dust were studied. Waste molecular sieve (S) was pretreated and selected as the carrier, potassium oxalate (K) and ferric citrate (T) as the active components. The reverse dissolution crystallization method was adopted and S@K/T, S@T/K, S@ T -K suppressors with different core–shell structure were prepared by different loading sequences. Their particle size, morphology and thermal pyrolysis behavior were compared. The results showed that the particle distribution of three powders is uniform and the dispersity of them is good. The active components of explosion suppression are evenly loaded on the waste molecular sieve carrier and they have different coating structure. The thermal desorption heat of them is 44.64 J/ g, 66.95 J/g and 92.9 J/g, respectively. Furthermore, the flame propagation characteristics of coal dust were tested by the Hartmann flame propagation device. The results showed that all powders had the effect of inhibiting the flame propagation of coal dust and the inhibition effect is S@ T -K, S@T/K and S@K/T from strong to weak. Combined with characterization results, the influence mechanism of the difference in the flame propagation inhibition effect of three suppressants was investigated. [ABSTRACT FROM AUTHOR]

• The dielectric relaxation phenomenon and detailed analysis of electrical characteristics of Nb-doped NBT-ST ceramics. • The important role of oxygen-vacancy defects formed by ion volatilization in ferroelectric relaxation. • The analysis of the impedance spectroscopy and fitting results analysis of the equivalent circuit model of impedance. 0.75(Na 0.5 Bi 0.5)TiO 3 –0.25SrTiO 3 – x Nb 2 O 5 (labeled as NBT–ST– x Nb, x =0.00, 0.01, 0.02, 0.03) ceramics were prepared by a solid-state reaction method. The crystal structure and grain morphology were characterized. Dielectric constant (ε r) and dielectric loss tangent (tanδ) could be observed in the dielectric spectroscopy and the modified Curie-Weiss law was used to analyze the relaxation behavior. According to the impedance spectroscopy, we used the equivalent circuit model to fit the impedance results. To better understand the relaxor behavior, the electric modulus was analyzed and indicated that there was a conduction process of charge carriers from long-range mobility to short-range mobility. The relaxation activation energy (E a) and conductance activation energy (E c) confirmed the oxygen vacancies (OVs) also played a significant role in the conduction process. [Display omitted] [ABSTRACT FROM AUTHOR]

Laser welding is one of the most potential methods for joining of electrical steel laminations, which is commonly used in motor, transformer and compressor. Because of the existence of multiple interfaces in the welding path, the heat transfer in laser welding of the electrical steel laminations is significantly different from that in the normal welding. In this study, a finite element model (FEM) considering the effects of interfaces has been developed in ANSYS to analyze the heat transfer in laser welding of electrical steel laminations. The contact elements with birth and death options were used to describe both the existed and the vanished statuses of the interfaces during welding. The simulation results showed that the temperature distribution in the zone beside the interfaces was discontinuous at first and then changed to be continuous after the interface vanished. The highest temperature fluctuated periodically during the welding process because of the effects of multiple interfaces. The joint area decreased with the increase of sheet thickness but was robust with respect to the normal pressure applied on the sheets and the contact statuses of the interfaces to some extent. The estimated joint areas at various welding velocities were validated by experimental results. This work provides a better understanding of the heat transfer in laser welding of the electrical steel laminations. [ABSTRACT FROM AUTHOR]

[Display omitted] • The wetting mechanism of low-rank coals was studied at the molecular level. • The method of combining molecular dynamics simulation and experiment is adopted. • Analyzed the molecular electrostatic potential. • Simulate the wetting of three kinds of surfactants on low-rank coals. The surfactants sodium dodecyl benzene sulfonate, dodecyl dimethyl betaine, and dodecyl trimethyl ammonium bromide were used to study the effect of an ionic surfactant on coal wettability. A lignite-surfactant-water system was constructed using the Wender coal chemical structure model and Materials Studio molecular simulation software, and the static potential of a single molecule was determined by quantum chemical calculations. The initial and equilibrium configurations of the system, relative concentration distribution, and mean-square displacement (MSD) of water molecules were analyzed thoroughly. Additionally, the surface tension and contact angle of aqueous surfactant solutions with different mass concentrations were measured to analyze the relationship between concentration and the rate of reduction of surface tension and of contact angle. The analysis showed that when the surface static potential of the lignite molecule was larger than that of water molecules, the water molecules were easily attracted and exhibited a wetting phenomenon. The water-surfactant-coal system gradually tended from an initial unstable state to a stable state with low energy. Specifically, the hydrophilic groups in the surfactant were tilted toward the water phase and the hydrophobic chains were adsorbed on the surface of coal, which helped enhance the wettability of the coal. The relative concentration distribution range of the SDBS was 26–52 Å, which was wider than the other two surfactants. Additionally, the MSD curve showed that the diffusion coefficient of the water molecules in the water-SDBS-coal system reached a maximum value of 4.23 × 10−2, resulting in accelerated wetting of the coal body. When the SDBS mass concentration was 3%, the surface tension decreased to the minimum value (21.86 mN/m) and the minimum contact angle was 16.12°. Based on the simulation results and experimental test data, the wettability of the three surfactants to lignite was SDBS > BS-12 > DTAB. The findings of this study help to better understand the wetting mechanism of surfactants on lignite, which is conducive to the rapid screening of surfactants with strong wetting ability on lignite, expanding the use of surfactants, and is of great significance to the control and prevention of coal dust pollution. [ABSTRACT FROM AUTHOR]

• Oxidation performance of stearic acid coated aluminum dust. • Influence of stearic acid coating on MEC of aluminum dust. • Effect of stearic acid coating on explosion characteristics of aluminum dust. • Analysis of explosion products of stearic acid coated aluminum dust. • Physical model of stearic acid coated aluminum dust explosion. To explore the effect of stearic acid coating on the explosion characteristics of aluminum dust, the flame propagation characteristics, minimum explosion concentration and explosion overpressure characteristics of aluminum (Al) and stearic acid coated aluminum dust (SA-Al) were studied by using the synchronous thermal analyzer, the improved Hartmann tube explosion test device, and 20 L explosion test device. Then micro morphology and composition of the explosion products were determined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and a physical model of stearic acid coated aluminum dust explosion was established. The results showed that the combustion intensity and flame propagation velocity of SA-Al dust cloud in the semi-closed pipe were lower than that of Al dust cloud, and the flame propagation was weak in the initial stage of explosion. The minimum explosion concentration (MEC), the optimal explosion concentration, the maximum explosion pressure (P max) and the maximum explosion pressure rise rate ((d P /d t) max) of SA-Al dust cloud were greater than that of Al dust cloud, and its products contained the incomplete combustion products AlO 2 , indicating that the stearic acid coating could abate the explosion sensitivity of Al dust cloud, and weaken the degree of oxidation of Al dust. In case of explosion, stearic acid coating could significantly enhance the explosion hazard of Al dust, resulting in a higher explosion risk. [ABSTRACT FROM AUTHOR]

A three dimensional coupled thermo-mechanical finite element model was established to simulate the process of ultrasonic spot welding of Cu to Al plates. Heat generation from both friction work of contact surfaces and material plastic deformation was considered in detail. The model did not only incorporate the material thermal softening effect but also acoustic softening effect, which can be deduced from experimental phenomena. The significant influence of acoustic softening effect was demonstrated by two comparison models (considering or not). Obtained results, including structural deformation and heat generation were compared between the two models. [ABSTRACT FROM AUTHOR]