Viruses as the prevailing biological entities are poorly understood in underground realms. Here, we establish the first metagenomic Groundwater Virome Catalogue (GWVC) comprising 280,420 viral ...species ( ≥ 5 kb) detected from 607 monitored wells in seven geo-environmental zones throughout China. In expanding ~10-fold the global portfolio of known groundwater viruses, we uncover over 99% novel viruses and about 95% novel viral clusters. By linking viruses to hosts from 119 prokaryotic phyla, we double the number of microbial phyla known to be virus-infected in groundwater. As keystone ultrasmall symbionts in aquifers, CPR bacteria and DPANN archaea are susceptible to virulent viruses. Certain complete CPR viruses even likely infect non-CPR bacteria, while partial CPR/DPANN viruses harbor cell-surface modification genes that assist symbiont cell adhesion to free-living microbes. This study reveals the unknown viral world and auxiliary metabolism associated with methane, nitrogen, sulfur, and phosphorus cycling in groundwater, and highlights the importance of subsurface virosphere in viral ecology.The authors present a metagenomic groundwater virome catalogue, unravelling unknown viral diversity, unique virus-host interaction, and diverse auxiliary metabolic genes in groundwater ecosystems.
Risk based inspection (RBI) methodology was proposed to evaluate the maintenance strategy in industrial process which was constructed in one of the units of Fujian Oil Refinery ISOMAX unit. Using ...classic definition of risk, both the probability and consequence of accident or failure were investigated respectively under the support of risk-specific code. All equipment in this unit were evaluated and categorized into five risk zone based on the RBI result which covered five levels. In addition, an application of the analytical hierarchy process (AHP) to select the most practicable maintenance strategy for equipment which was located in each risk rating scale was described. To arrange the hierarchic structure and evaluation, four main criteria were defined for pairwise judgments. Finally, four possible alternative strategies were proposed for administrators on the site.
► The CO diffusion is a uniform motion in the initial fire development process. ► The main factors of influence escape evacuation are determined. ► The staff’s escape velocity model in roadway is a ...piecewise function. ► The installation position of rescue capsules in No. I6 passageway is determined.
Fire in mine laneway leads to disordered ventilation system airflow, and smoke will result in staff poisoning. In such situation, it necessitates to install a rescue capsule in the common staff area. In this paper, the software Fluent was used to simulate the airflow conditions dynamically in No. 5 belt roadway of Kongzhuang Coal Mine when fire broke out. The migration law of CO front was determined. By underground escape experiments, personnel escape velocity model in pathway was established. Based on the numerical simulation and results of field experiments, the escape capsule installation location in the passageway of No. 5 belt roadway was ascertained.
•Flame thickness of methane explosion with a 20% filling ratio was revealed.•Increasing the distance from ignition source decreased the flame thickness.•Flame speed presented a trend of increasing ...and decreasing with distance.•Maximum overpressure followed a trend of decreasing, increasing and decreasing.
Through establishing a non-adiabatic open-ended steel pipe with a length of 20m and a cross-sectional area of 0.08m×0.08m, the changing rules of flame propagation and flame thickness of premixed methane/air explosion with a 10% fuel concentration and a 20% filling ratio were revealed. The experimental results show that the flame arrival time increased gradually with the increase of the distance from the ignition source, the maximum flame signal value initially increased along the pipe but then dropped. The flame thickness at a certain point could be measured by the time differences between vanishing moment and initial rising moment of flame signal at this point. With the increase of the distance from the ignition source, the flame thickness gradually decreased, the flame propagation speed presented a changing trend of increasing and decreasing, while the maximum overpressure followed a trend of decreasing, increasing and decreasing. The research results provide the scientific experimental basis for the reasonable setting mine explosion-resistant device, it is of great significance to effectively restrain the spread of explosion flame surface and avoid accident enlarging of gas explosion in coal mine.
According to risk characteristics of crowd crushing and trampling accidents in subway stations, Data Envelopment Analysis (DEA) method has been put forward to assess the risk of crowd crushing and ...trampling accidents in subway stations. By constituting risk input and output index system of crowd crushing and trampling accidents in subway stations, and introducing limiting weight factors to DEA classical model of BBC, the risk assessment model of crushing and trampling accidents in subway stations is established and applied in 13 subway stations in Beijing. The results agree with the actual conditions fairly well.
This paper focuses on an advanced layers of protection analysis (LOPA) method to assess the risk of a chemical process. Based on the chemical accident statistics between 2001 and 2014 in China, an ...acceptable risk function was built for chemical processes to confirm the acceptable risk value for an accident scenario. The assessment index for an emergency system was developed to assess the protective function of emergency protection based on analytic hierarchy process (AHP), and the probability of failure on demand (PFD) of emergency protection was obtained by fuzzy comprehensive assessment method and fuzzy set theory. The proposed method was applied to a methanol distillation installation. The result showed that the protections, including emergency protection, were sufficient because the probability of mitigation protection (1×10
−8
) was less than the acceptable risk value (3.04×10
−7
). The advanced LOPA method was proven to be able to improve the integrity and accuracy of traditional LOPA.
Viruses, as the most abundant organisms, significantly influence ecological function and microbial survival in soils, yet little was known about how viruses and virus-microbe interactions respond to ...environmental stresses induced by metal(loid) contaminations. Here, we conducted the metagenomic analysis to investigate the adaptative mechanisms of soil viruses under different metal(loid) contamination levels. By capturing a catalogue of 23,066 viruses, we found that viral communities exhibited the increased richness, diversity, and the temperate to lytic ratio in facing the highest metal(loid) contaminations. Meanwhile, viruses displayed obvious lineage-specific infection modes to distinct dominant hosts under different pollution levels. Viral functions linking to the inhibition of transcription and the enhancement of DNA repairment as well as multiple resistance not only contributed to coping with elevated multiple metal(loid) stresses, but also facilitated the adaptation and functioning of viral hosts. Moreover, the harmonious coexistence of viruses and resistant/pathogenic bacteria under the heaviest contaminations potentially exacerbated disseminating resistance and pathogenicity, while viruses under the lightest contaminations might be natural predators of resistant/pathogenic bacteria through lysing host cells. Overall, this study highlights the ecological importance of viral adaptation and the interactions between viruses and resistant/pathogenic bacteria in contaminated environments, contributing to developing virus-based approaches to soil restoration.
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•Viruses developed the highest biodiversity under the heaviest metal contaminations.•Enhanced DNA repair and suppressed transcription promoted the viral adaption.•Viruses carried the most MRGs, ARGs, and VFGs under the highest contaminations.•Viruses interacted with hosts in a mutualistic mode in the high-contaminated region.•Viruses potentially hunted resistant/pathogenic bacteria in the low-polluted area.
•On-site evaporation properties of LNG tanks are clarified by actual field data.•Average evaporation rate per unit time of the on-site tank is 0.11 %.•Field data and simulation methods are ...cross-validated by numerical model.•Influence of ambient temperature, liquid level and closed conditions was discussed.•The study aims to provide on-site evaporation data support for full-scale tanks.
In order to investigate the static evaporation characteristics of large LNG storage tanks in practical scenarios, this article analyzes the boil-off gas (BOG) generation rate and evaporation patterns of a large LNG storage tank using monitoring data collected during a shutdown period following an accident. The results reveal that the BOG generation rate fluctuates between 0 and 1.096 kg/s, with approximately 50 % of the data falling within the range of 0.229–0.417 kg/s. The evaporation rate per unit time for the storage tank consistently centers around 0.11 %. Additionally, a three-dimensional Computational Fluid Dynamics (CFD) model of the tank was developed to simulate and analyze temperature distribution and evaporation under various operational conditions. The simulated data exhibited a high degree of agreement with actual tank evaporation data. The study also explores the influence of different temperatures and liquid levels on tank evaporation using both on-site monitoring data and simulation. It was determined that the temperature difference between the interior and exterior of the tank is the primary factor affecting tank evaporation, while the impact of LNG levels in storage tanks is relatively minor. Furthermore, an increase in tank pressure raises the saturation temperature of LNG, effectively inhibiting BOG generation. This study represents the first analysis of monitoring data during the shutdown phase of large LNG storage tanks. The insights gained, along with the developed CFD model, offer critical theoretical and empirical support for the static management of large LNG storage tanks and contribute to the understanding of LNG storage tank evaporation characteristics.
Bacterial pathogens and viruses are the leading causes of global waterborne diseases. Here, we discovered an interesting natural paradigm of water "self-purification" through virus-pathogen ...interactions over a 1432 km continuum along the Middle Route of the South-to-North Water Diversion Canal (MR-SNWDC) in China, the largest water transfer project in the world. Due to the extremely low total phosphorus (TP) content (ND-0.02 mg/L) in the MR-SNWDC, the whole canal has experienced long-lasting phosphorus (P) limitation since its operation in 2015. Based on 4443 metagenome-assembled genomes (MAGs) and 40,261 nonredundant viral operational taxonomic units (vOTUs) derived from our recent monitoring campaign, we found that residential viruses experiencing extreme P constraints had to adopt special adaptive strategies by harboring smaller genomes to minimize nucleotide replication, DNA repair, and posttranslational modification costs. With the decreasing P supply downstream, bacterial pathogens showed repressed environmental fitness and growth potential, and a weakened capacity to maintain P acquisition, membrane formation, and ribonucleotide biosynthesis. Consequently, the unique viral predation effects under P limitation, characterized by enhanced viral lytic infections and an increased abundance of ribonucleotide reductase (RNR) genes linked to viral nuclear DNA replication cycles, led to unexpectedly lower health risks from waterborne bacterial pathogens in the downstream water-receiving areas. These findings highlighted the great potential of water self-purification associated with virus-pathogen dynamics for water-quality improvement and sustainable water resource management.
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