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At present, the tunnel construction engineering is increasingly transferring to southwest mountainous areas with complex terrain and geological conditions in China and presents a trend of "large buried depth, long tunnel line, high stress, strong karst, high water pressure, complex structure and frequent disasters." Taking water inrush disaster of karst tunnel fault zone as the research object, an evolutionary mechanical model of rock damage under the coupling action of stress-seepage is proposed in this paper. Besides, based on Comsol Multiphysics numerical software, the tunnel excavation is simulated, and the stress field, seepage field, and rock damage during the excavation are analyzed; thus, the mechanical mechanism of water inrush disaster from tunnel fault in karst area is obtained. The research results indicate that the tunnel excavation is a dynamic construction process, and the construction disturbance redistributes the original rock stress field and changes the state of seepage field. With the increase of excavation steps, the contour distribution of vertical stress ratio near the tunnel face is a circle shape, indicating that the rock mass is obviously disturbed by excavation, and the ratio of principal stress difference of rock mass at arch crown and bottom plate is large. Besides, the fault fissures expand and penetrate under the influence of tunnel excavation disturbance, increasing the permeability of fault zone in karst tunnel. In addition, the water seepage erosion takes away the granular rock mass, and the lithology becomes more weaker, which makes it possible for the occurrence of water inrush disaster in karst tunnel. Therefore, the advanced geological prediction is important in tunnel construction in karst area. The research results can be treated as an important theoretical basis for the prevention and treatment for water inrush disaster of fault zone in karst tunnel. [ABSTRACT FROM AUTHOR]

The influence of temperature on precipitation in China is investigated from two aspects of the atmospheric water cycle: available water vapor and atmospheric instability. Daily observations are used to analyze how rainfall intensities and its spatial distribution in mainland China depend on these two aspects. The results show that rainfall intensities, and especially rainfall extremes, increase exponentially with available water vapor. The efficiency of water vapor conversion to rainfall is higher in northwestern China where water vapor is scarce than in southeastern China where water vapor is plentiful. The results also reveal a power law relationship between rainfall intensity and convective instability. The fraction of convective available potential energy (CAPE) converted to upward velocity is much larger over southeastern China than over the arid northwest. The sensitivities of precipitation to temperature-induced changes in available water vapor and atmospheric convection are thus geographically reciprocal. Specifically, while conversion of water vapor to rainfall is relatively less efficient in southeastern China, conversion of CAPE to upward kinetic energy is more efficient. By contrast, in northwestern China, water vapor is efficiently converted to rainfall but only a small fraction of CAPE is converted to upward motion. The detailed features of these relationships vary by location and season; however, the influences of atmospheric temperature on rainfall intensities and rainfall extremes are predominantly expressed through changes in available water vapor, with changes in convective instability playing a secondary role. [ABSTRACT FROM AUTHOR]

Timely maintenance is crucial to ensure the long-term performance of asphalt pavements. Due to the large amount of greenhouse gases (GHG) emitted during construction, it is important to evaluate the environmental impacts of various maintenance technologies, so that the whole life impacts of asphalt pavements can be understood and reduced. This paper estimated the GHG emissions of 16 maintenance technologies in the four categories of surface seal or coating system, thin overlay system, hot recycling system and cold recycling system by using life cycle assessment (LCA), and identified the technologies and the combination of them that have the least GHG emissions. In order to compare the maintenance technologies on a level-playing basis, this study designed maintenance scenarios for the entire life cycle of the pavement, and established a system boundary where all maintenance scenarios are compared transparently for a defined functional unit. Results show that, among the preventive maintenance technologies, micro-surface and fog seal have the lowest GHG emissions. In order to meet the same performance requirements of highway pavement, cold recycling with extra overlay will generate more than twice GHG emissions that of hot recycling. Increasing the frequency of preventive maintenance, and reducing the occurrence of corrective maintenance can reduce GHGs emissions by 30%–45% in pavement life. Reasonably designed maintenance plan for the entire life cycle can significantly reduce the GHG emissions of asphalt pavements. • The CO 2 footprint of sixteen asphalt pavement maintenance technologies was analyzed. • Micro-surface and fog seal have the lowest GHG emissions. • Cold recycling with extra overlay will generate more than twice GHG emissions that of hot recycling. • Increasing the frequency of preventive maintenance can reduce the GHG emissions. [ABSTRACT FROM AUTHOR]

The Venus clam, Cyclina sinensis , is one of the most popular and nutritious shellfish species facing several pathogenic microbial invasions that have caused severe economic losses in China. Toll-like receptors (TLRs) play important roles in the innate immunity of molluscan species, but the available information of the C. sinensis hepatopancreas transcriptome and the results from a large-scale identification of TLRs remain limited. In this study, de novo transcriptome assembly and differential gene expression profiling of untreated (termed H) and Vibrio anguillarum -challenged (termed HV) groups of C. sinensis hepatopancreas were performed using the RNA-Seq platform. A total of 141,881,862 bp of high-quality clean reads were assembled into 163,129 unigenes from 206,495 transcripts with an N50 length of 1186 bp. All of these unigenes were then annotated and classified using the Swiss-Prot, Nr, Nt, KO, GO, KOG and KEGG databases. To understand and characterize the innate immune responses of C. sinensis challenged with V. anguillarum , a total of 4458 differentially expressed unigenes, including 2276 upregulated and 2182 downregulated genes, were identified, and some of these genes were associated with PRR signaling pathways in C. sinensis , including the TLR, the NOD-like receptor, the RIG-I-like receptor, NF-κB and the MAPK signaling pathways. From this transcriptome library, we then identified a total of 13 new TLRs that showed increased expression levels in the C. sinensis hepatopancreas at different time points after V. anguillarum infection, and these consisted of one P-TLR , one V-TLR , one Twin-TIR TLR , three Ls-TLRs and seven sP-TLRs. In summary, this study may significantly contribute to the knowledge of the innate immunity and defense mechanisms of C. sinensis in response to V. anguillarum stimulation and promote future research investigating the evolution and functions of TLRs in invertebrates. • The first transcriptome of Cyclina sinensis hepatopancreas challenged with Vibrio anguillarum were constructed. • A number of 4458 DEGs were calculated, of which were annotated in five PRR signaling pathways. • We selected obtained 13 TLRs that divided into five groups, but Ls-TLR2 could be similar to mccTLRs. • All TLRs of C. sinensis played significant roles in response to V. anguillarum infection by qRT-PCR. [ABSTRACT FROM AUTHOR]