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The densification of mono-sized regular octahedral particles under vibration is simulated by a DEM model. The model is validated by physical experiments. The effects of operating parameters including vibration amplitude and frequency are investigated. The obtained packing structures are characterized, and corresponding densification mechanisms are identified. The results indicate that vibration amplitude is more critical for densification compared to frequency, where a wide range of suitable amplitudes exists to realize the dense packing structures. Ordered packing structure exists in boundary region. The central region possesses good particle position randomness and orientation randomness, and the packing density for poured packing (initial loose packing) and vibrated packing (dense packing) in the central region are 0.670 and 0.684, respectively. During densification, contacts and constraints between particles decrease, and the stress within the structure becomes larger. The typical arrangement of neighboring particles is close to but not perfect face to face (F–F) contact. Particles in the boundary region experience more rotations and can form local ordered structures. These structures prevent the relative movement of individual particles but favor their movement as a whole. Particles in the central region have relatively little movement and rotation. The ordered structures formed at boundary is difficult to extend to the central region due to the restricted change of particle contact conditions.

The packing of cohesive particles is of paramount importance in many industries because the packing structure is closely related to process performance. A general relation between packing density and interparticle force was previously proposed based on packing structures formed without dynamic fluid flows. Its universality is examined here in two different packings, formed in settling and defluidization of static and dynamic fluids, respectively. First, it is shown that the packings of the same particles formed by two different methods have different structures because of different impact-induced pressures. Nevertheless, a one-to-one relationship between packing density and structural properties still holds regardless of the different packing methods, and the force distribution in those packings obeys similar rules. Finally, the packing densities obtained by the different methods are demonstrated to be universally correlated with the ratio of the interparticle force to the effective gravity. These findings indicate that different phenomena of particulate systems at a macro- or meso-scale may share similar microscopic origins, with the interparticle force playing a crucial role.

In this paper, the transition from random to ordered packings of mono-sized cylindrical particles under 3D mechanical vibration was simulated by discrete element method (DEM). The effects of particle aspect ratio, size of the particulate system and container wall on the granular crystallization were investigated. And the mechanisms were analyzed through the characterization of the order transition process in terms of packing density, coordination number (CN), orientational ordering parameter (O), nucleation and growth of cluster and granular temperature (θ). The results show that nearly perfect crystallization of mono-sized cylindrical particles can be achieved with specific aspect ratio and proper vibration conditions in a cylindrical container. The orientational ordering parameter demonstrates that the crystallization firstly starts from the container wall and then propagates inward gradually. The lower granular temperature in a cuboid container indicates less vibration energy transferred to the granular assembly compared with that in a cylindrical container, illustrating the critical role of container shape in crystallization. The vibrated crystallization of mono-sized cylindrical particles is analogous to entropy-driven process, which can be gradually achieved by the self-assembly of particles with parallel alignments along the already formed ordered clusters (nuclei) or the container wall. These results can help design complex and ordered granular structures.

Waste water treatment with adsorbents has become one of the most effective methods. In this work, we have reported the preparation of the flower-like Cu2MoS4/g-C3N4 composites. The Cu2MoS4 nanosheets were arranged in a flower-like structure by a simple one-step hydrothermal synthesis method and attached to g-C3N4 nanosheets. The as-prepared flower-like Cu2MoS4/g-C3N4 composites was found to have potential for the adsorption of RhB in aqueous solution. The microstructure of the product was analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscope (XPS), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET). The effects of the ratio of the composite material, the initial concentration of the dye and the contact time were explored. The Langmuir maximum adsorption capacity of the flower-like Cu2MoS4/g-C3N4 composites for RhB was reached 420.2 mg/g. Moreover, the adsorption process is consistent with the pseudo second-order kinetic model, the Langmuir isotherms model and the Freundlich isotherms model.

Electroreduction of CO2 to formate (ERCF) over a gas diffusion electrode with a Nafion-bonded carbon-supported Sn-based catalyst layer provides a promising approach for formate production. The ERCF performance is largely dependent on the carbon supports. However, the key influencing factors of the carbon supports for the ERCF performance have not yet been elucidated. We employed a variety of carbon supports with different pore structure features (activated carbon, acetylene black, and ordered mesoporous carbon) to explore the main factors influencing ERCF performance. The results showed that the pore size distribution was crucial for the ERCF performance. The ideal pore size was 5–20 nm. As it had the highest specific surface area within this pore size range among all the carbon supports examined, the ordered mesoporous carbon support obtained the highest ERCF performance (Faraday efficiency and current density for formate were 97.45 ± 2.97% and 80.12 ± 5.91 mA cm−2, respectively). Further analyses revealed that the increased ERCF performance was likely due to the large electroactive surface area, enhanced surface adsorption and activation capability of CO2, mesopore-induced proton transfer limitations for the hydrogen evolution reaction, and excellent charge transfer. This work is of significance for the further design of high-performance gas diffusion electrodes for the ERCF process.

The packing densification of mono-sized equilateral cylindrical particles under mechanical vibration is numerically reproduced using discrete element method (DEM). The influences of vibration frequency, amplitude and container size on the macro property (e.g. packing density) of each packing are studied. Meanwhile, various micro-properties including coordination number (CN), radial distribution function (RDF), local structures, contact types, particle position/orientation distributions, forces/stresses of the vibrated dense packing are characterized and compared with those of the loose initial poured packing. The results show that properly controlling vibration conditions can realize the transition of equilateral cylindrical particles from random loose packing (RLP) to random close packing (RCP). The maximum packing density without wall effects can reach about 0.7166, which agrees with experimental and numerical results in literature. Micro property analyses demonstrate that the average CN increases slightly after vibration. The RDF curves indicate three obvious peaks for both poured and vibrated packings. The distributions of intersection angles imply that the perpendicular arrangements of the cylindrical particles are common in both packing structures. From RLP to RCP, the probability of side-edge, bottom-edge and edge-edge contacts between two particles decreases, while that of side-side, side-bottom and bottom-bottom contacts increases. Both particle position and orientation distributions illustrate that the structure in the center of the vibrated packing is disordered. The distribution of strong forces follows the exponential law, while that of weak forces follows the power law. The static vertical stresses in both packings can be predicted by Janssen model. After vibration, a much denser and more stable structure with a larger saturation stress is obtained due to the reducing inter-particle friction effects.

This paper presents a systematic numerical investigation of static stress profile within a confined granular packing using discrete element method. The vertical and horizontal stress profiles are carefully identified within the packing structure, and the effects of container diameter and friction coefficient on the stress distributions are systematically investigated and analyzed. The results show a quantitative agreement between the vertical stress profile gauged at the bottom and the stress profile calculated within the packing structure. I.e. beyond a hydrostatic region, the static vertical stresses saturate exponentially with the packing depth. A positive correlation between the saturation stress and the container size and a negative correlation with the friction coefficient can be observed. Besides, it is also found that the well-known Janssen coefficient (or Janssen constant) is not a constant value; it decreases asymptotically to a constant with the packing depth, which implies a non-constant friction effects existed between the granular assemblies and the boundaries. And the analysis of contact forces within the packing structure also indicates a stabilized condition beyond the hydrostatic region. It is believed that these findings could develop a comprehensive insight on the stress distribution of granular matter.

Folic acid (FA) supramolecular gel was prepared in a mixture solvent of N -methylpyrrolidone (NMP)/H 2 O at a 1/1 volume ratio by using FA as gelator with a concentration of 0.4% (w/v). In the mixture solvent, NMP was first of time used as a good solvent to tune the solvent properties in order to be able to induce formation of FA supramolecular gel. The folic acid-gelatin (FA-GA) hybrid gels were synthesized by adding different amount of gelatin (GA) into FA gelator. The gelation temperature (T Gel ) of the FA-GA hybrid gel is 30 °C which is much higher than that of FA gel (10 °C). The gel to sol transition temperature (T GS ) is about 58 °C, which demonstrates that the hybrid gel has good stability at room temperature. The FT-IR and UV–vis spectra of FA-GA hybrid gel indicate that GA involves in the self-assembly process of FA via hydrogen bonding and π-π interactions with FA molecules. Owing to the π-π interaction happened between FA and GA molecules the fluorescence intensity of FA-GA gel is four times as high as that of FA gel. SEM images shows that the hybrid gel has a helical-fiber network structure which would enhance the gel strength to a great extent. Good stability, large specific surface and porosity in three-dimensional network structure of the FA-GA hybrid gel make it a highly promising adsorbent for dye adsorption. The FA-GA hybrid gel is able to absorb 63.5% of Congo red (CR), 68% of methyl blue (MB) and 44% of methyl orange (MO) respectively from their solutions.

Tetra (4-carboxyphenyl) porphyrin (TCPP) was loaded on the surface of Pt/g-C3N4 via a simple adsorption process, and the microstructure and chemical structure of the composites were characterized by high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV–visible diffused reflectance spectroscopy and photoluminescence spectroscopy. Loading TCPP onto Pt/g-C3N4 enhanced the visible-light-driven photocatalytic evolution of H2 from water. The TCPP/Pt/g-C3N4 composite with a TCPP loading of 1 wt% had the highest photoactivity, which was 2.1 times higher than that of Pt/g-C3N4. This improvement is attributed to enhanced visible light utilization by the TCPP/Pt/g-C3N4 resulting from the strong visible light response of TCPP. In addition, the formed organic heterostructure between TCPP and g-C3N4 with overlapping bad gaps accelerates the electron transfer and inhibits the recombination of the photogenerated electrons and holes on g-C3N4.

A coupled approach of discrete element method and pore network model (DEM-PNM) is developed for simulating particle–fluid flow. By this approach, the particle/solid flow is described at a particle scale by DEM and the fluid flow is described at a pore scale by PNM. The coupling scheme between DEM and PNM and the boundary conditions for realizing particle–fluid flows under different conditions are explicitly introduced. The capability is examined in three systems: a dynamic cell, a gas-fluidized bed, and a packed bed with lateral gas injection. The simulated results by the DEM-PNM approach agree with those results by either DEM-LBM (lattice Boltzmann method) approach or experiments. In particular, the simulated reasonable flow patterns in gas fluidization and lateral gas injection demonstrate the applicability of the proposed approach to complex particle–fluid flow. However, the current model presents less accuracy in dilute flow region and does not consider some important factors, which should be further improved in the future.

Densification of cubic particles under three-dimensional (3D) mechanical vibration was studied experimentally. Effects of vibration time (t), frequency (f), vibration amplitude (A), vibration acceleration (Г), container size (D) and particle sphericity (φ) on packing density (ρ) were comprehensively analyzed. To identify the effects of particle shape, the packing densification of cuboid 1 (12 mm × 12 mm × 28 mm) and cuboid 2 (4 mm × 8 mm × 16 mm) were systematically studied under the same conditions. The results show that the structure of cubic particles can be first densified from random loose packing (RLP) to random close packing (RCP) and then to ordered packing (OP) gradually. In comparison, cuboid 1 and cuboid 2 particles can only form RCP structure, but cannot achieve OP even under further vibration. Vibration parameters (t, f, A and Г) are shown to be important to the packing densification. Based on the results of varying f and A, A - f phase diagrams are established for choosing the optimal vibration parameters to achieve the desired dense packing structures. Besides, it is shown the size of container (wall effect) has monotonic influence on packing density, i.e., the larger container size corresponds to the less wall effect and higher packing density. Cubic particles can form ordered packing because of the geometrical symmetry with aspect ratio of 1. After eliminating the wall effect by extrapolating the packing densities in different sized containers, typical packing densities of the three types of particles are obtained with ρRLP = 0.658, ρRCP = 0.830 and ρOP = 0.965 for cubic particles; ρRLP = 0.625 and ρRCP = 0.740 for cuboid 1 particles; ρRLP = 0.591 and ρRCP = 0.731 for cuboid 2 particles. These findings indicate cubic particles are efficient in densification which can be readily realized through proper 3D mechanical vibration.

Packing densification of cubical particles under mechanical vibrations was dynamically simulated by using discrete element method (DEM). Effects of operating parameters such as vibration amplitude, frequency, vibration intensity, and container size (container wall) on packing densification were comprehensively investigated. The macro property such as packing density and micro properties such as coordination number (CN), radial distribution function (RDF), and particle orientation of the packings were analyzed and compared. It is found that mechanical vibration with proper vibration amplitude and frequency is effective for the densification of cubical particle packing. Packing structures of different packing densities display different properties, based on which random loose packing (RLP) and random close packing (RCP) of cubical particles are identified with the packing density of 0.591 and 0.683, respectively. Two densification mechanisms are discussed as the particle rearrangement is dominant for the transition from RLP to RCP and the crystallization along the container wall is dominant for the transition beyond RCP to ordering. The obtained results are useful for optimizing vibration conditions to generate dense packings and understanding the structural information of some fixed beds with cubical particles.

Systematic physical experiments examining the packing densification of mono-sized cylindrical particles subject to 3D mechanical vibration were carried out. The influence of vibration conditions such as vibration time, frequency, amplitude, vibration strength, container size, and the aspect ratio and sphericity of the particle on the packing density were analyzed and discussed. For each initial packing density with a certain aspect ratio, operating parameters were optimized to achieve much denser packing. The results indicate that the packing density initially increases with vibration time and then remains constant. The effects of vibration frequency and amplitude on the packing densification have similar trends, i.e. the packing density first increases with the vibration frequency or amplitude to a high value and then decreases; too large or small frequency or amplitude does not enhance densification. Increasing the container size can reduce container wall effects and help achieve a high packing density. Varying the particle aspect ratio and sphericity can lead to different dense random packing structures. Overall, based on results of the examined systems, the highest random packing density obtained in an infinite sized container can reach 0.73, which agrees well with corresponding numerical and analytical results in the literature.

Seahorses (family Syngnathidae) are ovoviviparous fish whose embryos can obtain paternal immunoprotection through the male's brood pouch, which is a specialized organ for pregnancy. Previous studies have revealed that seahorses have a unique immune system and alpha-2 macroglobulin (α2M) may be involved in male pregnancy. To ascertain the significance of α2M in the immune system of the brood pouch, the characteristics of the α2M gene were first investigated in the lined seahorse (Hippocampus erectus). In this study, α2M showed a broad expression pattern, with the highest expression in the liver and brood pouch. Interestingly, during the six-month seahorse culture, expression level of α2M in the liver was particularly decreased during brood pouch formation (fourth and fifth months), but was restored the complete development of this brood pouch (sixth months), and a similar expression occurred in the brood pouch. This suggests that the seahorse might be able to regulate its immune response while a new organ develops. Further investigation also examined the immune regulation of α2M in brood pouches by injecting lipopolysaccharide and polyinosinic-polycytidylic acid. The results showed that, after the challenge experiment, α2M expression in the inner pseudoplacenta was upregulated, along with other important immune factors, such as Toll-like receptors (TLRs), tumor necrosis factor-alpha (TNFα), interleukin-6 (IL-6) and interferon-gamma (IFNγ). Taken together, our results reveal that α2M plays an important role in immunoprotection of the brood pouch, and may provide new insights into studies of male pregnancy regulation in seahorses.

Sn-based gas diffusion electrodes (GDEs) are promising for electroreduction of CO2 to formate (ERCF) as they can alleviate CO2 mass transfer limitations. However, current electrodes suffer from large catalyst size or poor electron and/or ion connections. This limits ERCF performance. Here, we report a Sn-based GDE (IE-Sn) for ERCF fabricated via deposition of Sn nanoparticles onto a gas diffusion layer by using an impregnation-electroreduction method. The characterization results showed that the IE-Sn has small Sn catalyst size (16 nm) and excellent electronic and ionic transfer properties. Moreover, the faradaic efficiency (87.12 ± 4.28%) and partial current density for formate (62.79 ± 5.33 mA cm−2) obtained from the IE-Sn is 2.45-fold and 4.86-fold, respectively, of those of the traditional electrode. This ERCF performance is one of the best among recently reported Sn-based GDEs under similar conditions. Further analyses reveal that the enhanced ERCF performance of the IE-Sn is linked to the large electroactive surface area, enhanced adsorption capacity and chemisorption ability of CO2, better stabilization of CO2.– intermediate, and excellent ion/electron transfer. This study offers design rules to fabricate high-performance electrode materials for ERCF.

Seahorses, with brood pouch in adult males, are a bioindicator species that exhibit specialized reproductive strategy of “male pregnancy”. Bisphenol A (BPA), one of the most pervasive endocrine-disrupting chemicals (EDCs), is hazardous for reproductive, immune, and neurological systems. However, no evidence of BPA toxicity to the male-pregnant animals is available. Herein, the reproductive toxicity of BPA was evaluated in lined seahorses (Hippocampus erectus) following exposure to environmentally relevant concentrations (10, 100, and 1000 μg/L) through physiological, histological, and transcriptional analyses. Our results indicated BPA bioaccumulation to be positively correlated with exposure doses in both sexes. Ovarian failure was only observed in the high-dose BPA treatment group, accompanied by the apoptosis of follicular cells and up-regulation of pro-apoptotic genes. However, brood pouches maintenance were surprisingly inhibited at low concentration, and transcriptomic analysis revealed disturbed profiles of genes involved in the extracellular matrix and cell-cell adhesion pathways. Interestingly, seahorse testes were less sensitive to BPA exposure than that in other teleosts. Thus, our study suggests that BPA at environmentally relevant concentrations might cause reproductive dysfunction in seahorses, potentially exerting adverse effects on the seahorse population since most of them inhabit shallow coastal areas with prevalent estrogenic contaminants.

Objective Intestinal mucosal barrier damage is an important mechanism for the development of sepsis and multiple organ dysfunction syndrome. At present, there are no satisfactory and effective methods for the protection of the intestinal mucosal barrier. Jinzhi, the first fecal microbiota transplantation worldwide, is often used to treat critically ill patients; however, the specific mechanism involved in this process remains unclear. The aim of this study was to investigate the therapeutic effect and mechanism of Jinzhi intervention on mice with sepsis induced through treatment with lipopolysaccharide (LPS). Methods Mice were intraperitoneally injected with LPS to simulate intestinal mucosal barrier function damage in sepsis; intervention was performed through the oral administration of Jinzhi. The effect of Jinzhi on LPS-induced sepsis was analyzed by comparing the vital signs and survival rate of mice under different treatments. Pathological staining and enzyme-linked immunosorbent assay were used to identify the effects of LPS or treatment with Jinzhi on the intestinal mucosal barrier in mice. The effect of LPS or treatment with Jinzhi on the intestinal flora was analyzed via 16S rRNA gene sequencing of ileal contents. Results Immunohistochemistry and enzyme-linked immunosorbent assay showed that treatment with LPS increased levels of inflammatory factors (interleukin-1α, interleukin-6, tumor necrosis factor-α), caspase-3, and caspase-8 in the serum and ileum, and destroyed the tight junction between epithelial cells. Intervention with Jinzhi reduced levels of serum LPS and tumor necrosis factor-α, and repaired the tight junction between epithelial cells. Furthermore, 16S rRNA gene sequencing analysis showed that treatment with Jinzhi improved the diversity and physiological function of the intestinal flora. Conclusions These results suggest that Jinzhi may be a promising option for the treatment of sepsis caused by LPS, and emphasize that Jinzhi exerts a recovery effect on the imbalance of intestinal flora.

Objective To evaluate the effect on acne vulgaris of pricking-bloodletting cupping at Dazhui (GV 14) under acupuncture anesthesia, and establish whether providing anesthesia to the treatment area by manipulating Hegu (LI 4) and Quchi (LI 11) might have an additional therapeutic benefit. Methods Thirty-eight patients were recruited and randomized into a control group and an intervention group with a single-blind (observer-blind) method. The control group was treated by pricking-bloodletting cupping at Dazhui (GV 14) and the studied group by pricking-bloodletting cupping at Dazhui (GV 14) under acupuncture anesthesia at Hegu (LI 4) and Quchi (LI 11). Both groups were treated twice weekly for 6 weeks. The analgesic and therapeutic effects of acupuncture were evaluated on a visual analog scale (VAS) and global acne grading system (GAGS), respectively. Results There were differences in the VAS scores of pain on pricking and in the pricked area, and the duration of pain between the groups. After 12 treatments, there was a significant reduction in GAGS scores from baseline in both groups, but there was no significant difference between the groups. Conclusion Acupuncture anesthesia at Hegu (LI 4) and Quchi (LI 11) is an effective means of alleviating the pain of pricking-bloodletting cupping and reducing the duration of pain in the treatment area. Pricking-bloodletting cupping at Dazhui (GV 14) improves the skin lesions of patients with moderate acne vulgaris, but acupuncture anesthesia does not appear to have an additional therapeutic effect.

Hyperspectral remote sensing provides fine spectral information for diagnosing crop disease severity, and in this paper the application of the hyperspectral remote sensing in identifying cotton verticillium disease severity was investigated. The wavelet transform was employed to extract the principal information and reduce the dimensions of the hyperspectral reflectance data, which were measured for cotton blades in different disease severity. Then, four identification models were built using discriminant analysis, back propagation (BP) neural network, genetic back propagation (GA-BP) neural network and support vector machine (SVM). The effects of the four models were examined and it was indicated that the SVM approach was the best.

MODIS derived aerosol optical depths (AODs) at 550 nm are compared with sunphotometer CE318 measurements at 7 sites located at Yangtze River Delta (YRD) in China from July to October, 2007. The evaluation result indicates that MODIS AODs (Collection 5, C005) are in good agreement with those from CE318 in dense vegetation regions, but show more differences in those regions with complex underlying surface (such as at lake water and urban surface sites). Reasons for these differences are discussed after removing cases with significant errors caused by validation scheme. The final validation result shows that MODIS AODs are in good agreement with CE318 with a correlation coefficient of 0.85 and RMS of 0.15. 90% of MODIS cases fall in the range of Δ τ = ± 0.05 ± 0.20 τ , indicating MODIS aerosol retrieval algorithm, aerosol models and surface reflectance estimate are generally suitably reasonable for aerosol retrieval in YRD. However, MODIS AODs show a systemic errors with fitted line of y = 0.75 x + 0.13, indicating underestimation of AOD when aerosol loadings are high. Aerosol models and surface reflectance estimations are dominant sources of MODIS aerosol retrieval errors.

The magnetic properties and magnetocaloric effect in Fe 4 MnSi 3 B x compounds with x =0, 0.05, 0.10, 0.15, 0.20, 0.25 have been investigated. X-ray diffraction study shows that all these compounds investigated crystallize in the Mn 5 Si 3 -type structure with space group P6 3 /mcm. Boron insertion in the host ternary silicide Fe 4 MnSi 3 does not change the crystal symmetry, only leads to an increase of the lattice parameters, indicating the B atoms entered the interstitial sites. With increasing B content, the Curie temperature shifts to higher temperatures. The maximal magnetic-entropy changes of the Fe 4 MnSi 3 B x compounds with x =0, 0.10 and 0.20 are about 1.8 J/(kg·K), 1.8 J/(kg·K) and 1.6 J/(kg·K), respectively, for a field change from 0 to 1.5 T.

Based on the ‘average stress in the matrix’ concept of Mori and Tanaka (Mori, T., Tanaka, K., 1973. Average stress in matrix and average elastic energy of materials with misfitting inclusion. Acta Metall. 21, 571–580) a micromechanical model is presented for the prediction of the elastic fields in coated inclusion composites with imperfect interfaces. The solutions of the effective elastic moduli for this kind of composite are also obtained. In two kinds of composites with coated particulates and fibers, respectively, the interface imperfections are taken to the assumption that the interface displacement discontinues are linearly related to interface tractions like a spring layer of vanishing thickness. The resulting effective shear modulus for each material and the stress fields in the composite are presented under a transverse shear loading situation.