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In underground spaces, corrugated steel plate (CSP) pipe-arches may experience local buckling instability, which can subsequently lead to the failure of the entire structure. Recently, sandwich CSP pipe-arches have been used to enhance the stability of embedded engineering outcomes, and their buckling behaviors require in-depth research. In this paper, we establish a theoretical model by simplifying soil support and using Hoff sandwich plate theory to focus on the local buckling stability of the straight segment in embedded sandwich CSP pipe-arches using the Rayleigh–Ritz method. Through stability analysis, the instability criteria for embedded sandwich CSP pipe-arches are analytically determined. Numerical calculations reveal that the critical buckling load of a sandwich CSP pipe-arch is affected by several factors, including the elastic modulus, thickness, Poisson's ratio, rotational constraint stiffness, and the length of the straight segment. Specifically, increasing the thickness of the sandwich CSP pipe-arch can substantially enhance the critical buckling load. Meanwhile, the wavenumber is affected by the elastic modulus and the length of the straight segment. The analytical results are in agreement with those obtained from finite element analysis. These findings provide a theoretical basis and guidance for the application of sandwich CSP pipe-arches in fields such as subway stations, tunnel construction, underground passages, and underground parking facilities. [ABSTRACT FROM AUTHOR]

The polymer/nano-inorganics composite microsphere possesses excellent application prospects, but it is difficult to resolve the problem of the aggregation of nano-inorganic particles in polymer and the affinity between inorganics and polymer matrix. In this study, the preparation and characterization of polystyrene (PS)/ethylene vinyl acetate copolymer (EVA)/CaCO3 microspheres fabricated via a novel phase inversion emulsion process are described. By this one-pot method, the PS/EVA/CaCO3 microspheres are obtained by firstly converting styrene monomer containing EVA and nano CaCO3 into droplets dispersed in water with help of emulsifiers and a following polymerization. Because the inorganic nanoparticles are ultrasonically dispersed in liquid monomer mixture before the polymerization, the aggregation of nano-inorganic particles could be prevented to a great extent. The EVA is designed to enhance toughness of polystyrene matrix and increase the affinity between polymer and inorganic particles. The morphological structure of PS/EVA/CaCO3 microspheres is that nano CaCO3 particles are embedded both in the interior and on the surface of the microspheres. The micro-sized PS/EVA/CaCO3 microspheres showed a significantly improved mechanical property and a better heat resistance. This technique also offers the possibility for fabricating many kinds of new and useful polymer/inorganic microspheres with tailored performance by using special monomers and inorganic particles. [ABSTRACT FROM AUTHOR]

Purpose: Resilience is considered as a protective factor that can assist individuals to reduce post-traumatic stress reactions. In recent years, armies in many countries have widely implemented resilience training programs before deployment to prevent or reduce post-deployment combat stress reactions. Therefore, this study aims to review what is known about resilience interventions for military personnel in pre deployment. Methods: Based on Arskey and O'Malley's framework, a scoping review was completed. This review was performed through searching databases including PubMed, Embase, Web of Science, Medline and the Cochrane Library, and screening literature to extract data, finally summarizing the findings. Results: A total of 25 studies focusing on resilience interventions for military personnel in pre deployment were involved and analyzed using intervention approaches, outcome measures, intervention effects, and so on. Conclusion: Based on the existing evidence in this review, it is cautiously believed that the resilience intervention program for military personnel before deployment is effective. However, there is no single effective best method even the same type intervention can make different effects in different situations and populations. Therefore, the population differences and context should be fully considered in constructing and implementing program to build military personnel resilience. [ABSTRACT FROM AUTHOR]

The natural and fiber-reinforced resin matrix composites have been increasingly and widely applied in society in order to improve the environment and promote sustainable development. In the first part of this article, the major foci of recent research on natural fiber composites are reviewed in detail, including fiber surface treatment, fiber agglomeration and dispersion, interfacial transcrystallinity, impact strength, foaming technique, inflaming retardance, biodegradable resin matrix and nanofiber reinforcement techniques. The fiber surface treatment and fiber dispersion are important factors in improving the mechanical properties of the natural fiber composites. The interfacial transcrystallinity can be generated on natural fibers owing to the rough surfaces. The natural fiber composites have a low impact strength. In order to reduce the density and improve the flame retardant effect of the composites, both the foaming technique and flame-retardant technology are studied in detail. The biodegradable resin matrix and natural fibers can be mixed to prepare fully-degradable composite materials. Using the natural nano fiber reinforcements in reinforcing resins is another important research area. In the second part of this article, the applications of these composites are summarized systematically, especially those involving the automotive industry, household appliances, construction materials, packaging materials and boards of musical instruments. Currently, the automotive industry and the production of construction materials are the most important application areas of these composites.

Polyaniline (PANI), as a conductive polymer, has been widely used in the corrosion protection of polymer coatings due to its high electrical conductivity and passivation effect. However, the agglomeration tendency and the difficulty of dispersion in the polymer hinder the anti-corrosion properties of PANI fillers. Therefore, in this paper, PANI nanorods were in situ polymerized on the surface of nitrogen and fluorine dual-doped graphene oxide (NFGO) layers to prepare PANI/NFGO composites and used to improve the anti-corrosion performance of waterborne epoxy coatings. The doped N elements and CF conformation with semi-ionic C–F bonds in NFGO enhanced the electrical conductivity and modified the graphene electric cloud distribution to form a fast conductive pathway in the graphene layer. In addition, the oxygen-containing groups in NFGO provided a site for the polymerization of PANI nanorods and enhance their hydrophilicity and dispersibility. Besides the capability of filling the micro-pores in the coating, the large specific surface area, the high electrical conductivity of NFGO, and the compact junction with PANI enable the electron transfer in a larger area, which increases the area of the inhibitor layer and ultimately enhanced the anti-corrosion performance. The corrosion resistance performance was investigated via electrochemical impedance spectroscopy (EIS) and salt spray tests. PANI/NFGO/WEP showed the highest corrosion resistance in EIS with the Rct value of 1.213 × 1010 Ω cm2, which was more than one order of magnitude higher than WEP. The excellent anti-corrosion properties were due to the synergistic effect of the physical properties of NFGO and the passivation effect of PANI nanorods. [ABSTRACT FROM AUTHOR]

In this paper, the effects of hyperbranched polyamide on the properties of sisal fiber reinforced polypropylene composites were studied. And the microstructure, fluidity, mechanical properties, and thermal stability of the composites were characterized. The results show that hyperbranched polyamide can significantly improve the interfacial bonding between fiber and matrix. When the fiber content is 20%, the melt flow rate can increase by 54%. Meanwhile, the tensile property of the composite increases by 50%, the impact strength of silane-treated fiber composite increases by 24%. However, the thermal stability of the composite decreases slightly after the addition of hyperbranched polyamide. [ABSTRACT FROM AUTHOR]

Anaerobic fungi, though low in abundance in rumen, play an important role in the degradation of forage for herbivores. When only anaerobic fungi exist in the fermentation system, the continuous accumulation of metabolites (e.g., hydrogen (H2) and formate) generated from their special metabolic organelles—the hydrogenosome—inhibits the enzymatic reactions in the hydrogenosome and reduces the activity of the anaerobic fungi. However, due to interspecific H2 transfer, H2 produced by the hydrogenosome can be used by other microorganisms to form valued bioproducts. This symbiotic interaction between anaerobic fungi and other microorganisms can be used to improve the nutritional value of animal feeds and produce value-added products that are normally in low concentrations in the fermentation system. Because of the important role in the generation and further utilization of H2, the study of the hydrogensome is increasingly becoming an important part of the development of anaerobic fungi as model organisms that can effectively improve the utilization value of roughage. Here, we summarize and discuss the classification and the process of biomass degradation of anaerobic fungi and the metabolism and function of anaerobic fungal hydrogensome, with a focus on the potential role of the hydrogensome in the efficient utilization of biomass. [ABSTRACT FROM AUTHOR]

Graphene materials are widely used as a physical barrier when applying anticorrosion polymer coatings due to their large surface area and layered structure. However, the electrical conductivity of intrinsic graphene can accelerate galvanic corrosion and shorten the protection period. In this work, fluorine and nitrogen co-doped graphene oxide (FNGO) was synthesized by a hydrothermal process and acted as an anticorrosion filler in waterborne styrene acrylic coatings. Styrene acrylic coatings with 0.4 wt% FNGO showed a corrosion current density that was two orders of magnitude lower than the other samples in the potential polarization test and the largest impedance modulus in the electrochemical impedance spectroscopy results. The outstanding corrosion protection was attributed to the graphene acting as a physical barrier and the synergistic effect of the doped fluorine and nitrogen. In addition to the ‘labyrinth effect’ of the graphene matrix, the nitrogen atoms inserted in the graphene plane and fluorine atoms grafted on the graphene simultaneously adjusted the electrical properties of graphene, prohibiting electron transport between it and the styrene acrylic resin matrix. This result indicates that doped graphene oxide has great potential to increase the corrosion resistance of waterborne coatings. [ABSTRACT FROM AUTHOR]

In this paper, sisal fibers were modified by different methods such as alkali treatment, γ-aminopropyltriethoxysilane treatment, tetraethylorthosilicate (TEOS) sol-gel treatment, TEOS, and silane combination treatment. The effects of different modification methods on the properties of sisal fibers were studied by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and universal material testing machine. The results show that the combination treatment fiber has the best heat resistance and the most obvious improvement in tensile properties, the tensile strength and modulus increase by 31.58% and 15.82%, respectively. [ABSTRACT FROM AUTHOR]

In order to improve the mechanical properties of sisal fiber-reinforced polypropylene composites, the sisal fibers were grafted with poly(amidoamine) dendrimer and the effects of grafting generations on the mechanical properties of composites were studied. The results reveal that the tensile, flexural, and impact strength of the composites are improved considerably with the poly(amidoamine) dendrimer grafting treatment. For the 2.0 generation treatment with the poly(amidoamine) dendrimer, the tensile, flexural, and impact strength of the composites at 30 wt% fiber loading increase by 29%, 13%, and 54%, respectively. However, the thermal and mechanical properties of the sisal fibers decrease after prolonged grafting treatment. [ABSTRACT FROM AUTHOR]

Objective: Previous research reported that dietary addition with phytosterols improved the energy utilisation of the rumen microbiome, suggesting its potential to alleviate the negative energy balance of perinatal cows. This experiment aimed to explore the effects of feeding phytosterols on the metabolic status of perinatal cows through plasma metabolomics and faecal bacteria metabolism., Methods: Ten perinatal Holstein cows (multiparous, 2 parities) with a similar calving date were selected four weeks before calving. After 7 days for adaptation, cows were allocated to two groups (n = 5), which respectively received the basal rations supplementing commercial phytosterols at 0 and 200 mg/d during a 42-day experiment. The milk yield of each cow was recorded daily after calving. On days 1 and 42, blood and faeces samples were all collected from perinatal cows before morning feeding for analysing plasma biochemicals and metabolome, and faecal bacteria metabolism., Results: Dietary addition with phytosterols at 200 mg/d had no effects on plasma cholesterol and numerically increased milk yield by 1.82 kg/d (p>0.10) but attenuated their negative energy balance in perinatal cows as observed from the significantly decreased plasma level of β-hydroxybutyric acid (p = 0.002). Dietary addition with phytosterols significantly altered 12 and 15 metabolites (p<0.05) within the plasma and faeces of perinatal cows, respectively. Of these metabolites, 5 upregulated plasma fatty acids indicated an improved energy status (i.e., C18:1T, C14:0, C17:0, C18:0, and C16:0). Milk yield negatively correlated with plasma concentrations of ketone bodies (p = 0.035) and 5-methoxytryptamine (p = 0.039). Furthermore, dietary addition with phytosterols at 200 mg/d had no effects on fermentation characteristics and bacterial diversity of cow faeces (p>0.10) but improved potentially beneficial bacteria such as Christensenellaceae family (p<0.05) that positively correlated with feed efficiency., Conclusion: Dietary addition with phytosterols at 200 mg/d could effectively improve the energy status in perinatal cows by attenuating their negative energy balance.