101 research outputs found

    Experimental study on mechanical performance of partially precast steel reinforced concrete beams

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    [EN] In order to exploit the potentials in mechanical and constructional performance of steel reinforced concrete structures and prefabricated structures, three innovative kinds of partially precast steel reinforced concrete beams, which are abbreviated here as PPSRC, HPSRC and PPCSRC beam, are presented in this paper. The PPSRC beam is composed of two parts, which are the precast outer shell with high-performance concrete and the cast-in-place inner part with common-strength concrete. Meanwhile, on the basis of PPSRC beam, the PPCSRC beam applies castellated steel shape and the HPSRC beam keeps the beam core hollow. With the aim to investigate the mechanical behavior, failure mode and bearing capacity of the PPSRC, PPCSRC and HPSRC beams, a static loading experiment with twenty four specimens was carried out. The effects of aspect ratio, construction method, section shape, concrete flange and strength of concrete were critically examined. Test results indicate that the HPSRC, PPCSRC and PPSRC beams both exhibit similar mechanical performance and bonding performance. The flexural capacity and shear capacity are seldom affected by the construction method and section shape, and increase with the increasing of the cast-in-place concrete strength. The shear strength of the specimens is significantly affected by the concrete flange and aspect ratio.Yang, Y.; Xue, Y.; Yu, Y.; Liu, R. (2018). Experimental study on mechanical performance of partially precast steel reinforced concrete beams. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 107-114. https://doi.org/10.4995/ASCCS2018.2018.6942OCS10711

    Improving alignment accuracy on homopolymer regions for semiconductor-based sequencing technologies

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    BACKGROUND: Ion Torrent and Ion Proton are semiconductor-based sequencing technologies that feature rapid sequencing speed and low upfront and operating costs, thanks to the avoidance of modified nucleotides and optical measurements. Despite of these advantages, however, Ion semiconductor sequencing technologies suffer much reduced sequencing accuracy at the genomic loci with homopolymer repeats of the same nucleotide. Such limitation significantly reduces its efficiency for the biological applications aiming at accurately identifying various genetic variants. RESULTS: In this study, we propose a Bayesian inference-based method that takes the advantage of the signal distributions of the electrical voltages that are measured for all the homopolymers of a fixed length. By cross-referencing the length of homopolymers in the reference genome and the voltage signal distribution derived from the experiment, the proposed integrated model significantly improves the alignment accuracy around the homopolymer regions. CONCLUSIONS: Besides improving alignment accuracy on homopolymer regions for semiconductor-based sequencing technologies with the proposed model, similar strategies can also be used on other high-throughput sequencing technologies that share similar limitations

    In-situ synthesis of ultra-fine ZrB2–ZrC–SiC nanopowders by sol-gel method

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    © 2019 Elsevier Ltd and Techna Group S.r.l. ZrB2–ZrC–SiC nanopowders with uniform phase distribution were prepared from cost-effective ZrOCl2·8H2O by a simple sol-gel method. The synthesis route, ceramization mechanism and morphology evolution of the nanopowders were investigated. ZrB2–ZrC–SiC ceramic precursor can be successfully obtained through hydrolysis and condensation reactions between the raw materials. Pyrolysis of the precursor was completed at 650 °C, and it produced ZrO2, SiO2, B2O3 and amorphous carbon with a yield of 39% at 1300 °C. By heat-treated at 1500 °C for 2 h, highly crystallized ZrB2–ZrC–SiC ceramics with narrow size distribution were obtained. With the holding time of 2 h, both the crystal size and the particle size can be refined. Further prolonging the holding time can lead to serious particles coarsening. Studies on the microstructure evolution of the generated carbon during the ceramic conversion demonstrates the negative effect of the ceramic formation on the structure order improvement of the carbon, due to the large amount of defects generated in it by the boro/carbothermal reduction reactions

    Effect of bioaugmentation on gas production and microbial community during anaerobic digestion in a low-temperature fixed-bed reactor

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    Low temperature is one of the limiting factors for anaerobic digestion in cold regions. To improve the efficiency of anaerobic digestion for methane production in stationary reactors under low-temperature conditions, and to improve the structure of the microbial community for anaerobic digestion at low temperatures. We investigated the effects of different concentrations of exogenous Methanomicrobium (10, 20, 30%) and different volumes of carbon fiber carriers (0, 10, 20%) on gas production and microbial communities to improve the performance of low-temperature anaerobic digestion systems. The results show that the addition of 30% exogenous microorganisms and a 10% volume of carbon fiber carrier led to the highest daily (128.15 mL/g VS) and cumulative (576.62 mL/g VS) methane production. This treatment effectively reduced the concentrations of COD and organic acid, in addition to stabilizing the pH of the system. High-throughput sequencing analysis revealed that the dominant bacteria under these conditions were Acidobacteria and Firmicutes and the dominant archaea were Candidatus_Udaeobacter and Methanobacterium. While the abundance of microorganisms that metabolize organic acids was reduced, the functional abundance of hydrogenophilic methanogenic microorganisms was increased. Therefore, the synergistic effect of Methanomicrobium bioaugmentation with carbon fiber carriers can significantly improve the performance and efficiency of low-temperature anaerobic fermentation systems

    The genome of hibiscus hamabo reveals its adaptation to saline and waterlogged habitat

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    Hibiscus hamabo is a semi-mangrove species with strong tolerance to salt and waterlogging stress. However, the molecular basis and mechanisms that underlie this strong adaptability to harsh environments remain poorly understood. Here, we assembled a high-quality, chromosome-level genome of this semi-mangrove plant and analyzed its transcriptome under different stress treatments to reveal regulatory responses and mechanisms. Our analyses suggested that H. hamabo has undergone two recent successive polyploidy events, a whole-genome duplication followed by a whole-genome triplication, resulting in an unusually large gene number (107 309 genes). Comparison of the H. hamabo genome with that of its close relative Hibiscus cannabinus, which has not experienced a recent WGT, indicated that genes associated with high stress resistance have been preferentially preserved in the H. hamabo genome, suggesting an underlying association between polyploidy and stronger stress resistance. Transcriptomic data indicated that genes in the roots and leaves responded differently to stress. In roots, genes that regulate ion channels involved in biosynthetic and metabolic processes responded quickly to adjust the ion concentration and provide metabolic products to protect root cells, whereas no such rapid response was observed from genes in leaves. Using co-expression networks, potential stress resistance genes were identified for use in future functional investigations. The genome sequence, along with several transcriptome datasets, provide insights into genome evolution and the mechanism of salt and waterlogging tolerance in H. hamabo, suggesting the importance of polyploidization for environmental adaptation.DATA AVAILABILITY: The data supporting the findings of this work are available within the paper and its Supporting Information files. The data sets generated and analyzed during this study are available from the corresponding author upon request. All the whole-genome raw data generated during this study have been deposited in the SRA database under BioProject number PRJNA759075. Transcriptome clean data have been deposited in the SRA database under BioProject number PRJNA759717. The final chromosome-scale genome assembly and annotation data have been deposited in the Figshare database (https://doi.org/10.6084/m9.figshare.19142558.v1).Six Talent Peaks Project of Jiangsu Province (NY-042); Open Fund of the Jiangsu Key Laboratory for the Research and Utilization of Plant Resources (JSPKLB201928); Talent Training Funds of the Institute of Botany, Jiangsu Province and Chinese Academy of Sciences.https://academic.oup.com/hrBiochemistryGeneticsMicrobiology and Plant Patholog

    Vitamin D and cause-specific vascular disease and mortality:a Mendelian randomisation study involving 99,012 Chinese and 106,911 European adults

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    2D Organic–Inorganic Hybrid Perovskite Quantum Well Materials and Their Dramatical X-ray Optoelectronic Properties

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    Two-dimensional organic–inorganic hybrid perovskites (2D OIHPs) have attracted extensive attention in the field of X-ray detection due to their excellent stability compared to traditional three-dimensional OIHPs and the strong optoelectronic response to X-ray along the quantum wells. In this review, the nucleation and growth process as well as intermolecular forces for controlling out-of-plane growth are summarized along with the oriented growth mechanism. The optoelectronic properties in 2D OIHP under irradiation of X-ray are also discussed. Finally, conclusions and outlook for orientation 2D OIHP quantum wells and their challenges in application of direct X-ray detection are given. This review will provide a basic understanding on the strategy of designing 2D OIHP thick films as promising X-ray photoconductors, which may inspire the development of next-generation X-ray detectors

    Solving the Moment Amplification Factor of a Lateral Jet by the Unsteady Motion Experimental Method

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    In this paper, unsteady motion tests of a lateral jet adjusting an air vehicle’s attitude are carried out. Curves of pitch moment amplification factors (KM) for a lateral jet versus angle of attack (α) are obtained using a wind tunnel free-flight test technique with a jet and data processing method. This new method overcomes the disadvantage of previous experiments that can study only one unsteady characteristic. The free-flight test technique in the proposed method ensures that the test model can be coupled in real-time with multiple parameters (unsteady flow caused by the jet, unsteady air vehicle aerodynamic force, and unsteady air vehicle motion). This approach simulates an actual air vehicle’s complete jet test process and ensures more authentic and reliable test results. In the new data processing method, continuous data curves are fitted to discrete data points, making it easier to convert the angular displacement versus time curve into the pitch moment versus α curve to obtain KM. The results show that when the pressure of the micro high-pressure gas cylinder is 2.0 MPa, KM is below 1, indicating that the lateral jet does not significantly promote the pitching moment. When the gas cylinder pressure is 4.0 MPa and the angle of attack is 5° α| KM is greater than 1, and the lateral jet promotes the pitching moment. When 16° α| KM is less than 1, and the lateral jet does not significantly contribute to the pitching moment. It was further found that KM decreases slowly with increasing α. When |α| > 30°, the influence of the jet on the pitching moment nearly disappears
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