Ecological vulnerability assessment of coral islands and reefs in the South China Sea based on remote sensing and reanalysis data

Coral reefs are ecosystems that are highly vulnerable to external environmental impacts, including changes associated with ocean acidification and global warming. Assessing the vulnerability of coral reef growth environments over large areas of the sea is a difficult and complex process, as it is influenced by many variables. There are few studies on environmental vulnerability assessment of coral islands and reefs in the South China Sea. It is therefore particularly important to understand the environmental sensitivity of corals and how coral communities respond to changes in climate-related environmental variables. In this study, indicators were selected mainly from natural environmental factors that hinder the development of coral reefs. The sea surface temperature (SST), sea surface salinity (SSS), wind velocity (WV) and direction, sea level height (SL), ocean currents (OC), and chlorophyll concentration (Chl) of coral reefs in South China Sea Island were integrated to calculate the coral reef environmental vulnerability region. In a GIS environment, Spatial Principal Component Analysis (SPCA) was used to develop sensitivity models and evaluate the ecological vulnerability of coral reefs. Based on the Environmental vulnerability indicator (EVI) values, the study area was classified as 5 grades of ecological vulnerability: Potential (0.000–0.577), Light (0.577–0.780), Medium (0.780–0.886), Heavy (0.886–0.993) and Very Heavy (0.993–1.131). Sensitivity models identified regional gradients of environmental stress and found that some coral reefs in western Malaysia and southwestern Philippines have higher vulnerability. Meanwhile, the study found that the reefs of Paracel Islands and Macclesfield Bank areas of medium vulnerability. Future use of high-precision data from long time series will allow better estimates of site-specific vulnerability and allow for the precise establishment of marine protected areas so that the ecological diversity of coral reefs can be sustained

Research on Surface Integrity and Fatigue Properties in the Turning of TC17 Titanium Alloy Based on the Response Surface Method

Titanium alloy parts are more and more widely used in the field of aerospace. In order to improve the service life of titanium alloy parts, the response surface method was used to study surface residual stress and roughness under different turning parameters. In addition, a mathematical model was established through multiple linear regression to determine the relationship between surface integrity parameters and fatigue life. The test results indicate that the turning parameters have an effect on surface residual stress in the order of feed rate > depth of cut > cutting speed and on surface roughness in the order of feed rate > cutting speed > depth of cut. The analysis results of surface integrity show that the residual compressive stress on the surface has the greatest impact on fatigue life, followed by surface roughness. The fatigue life increases with the increase in residual compressive stress and decreases linearly with the increase in surface roughness. The feed rate has a significant impact on residual stress and surface roughness. Therefore, under the experimental conditions of this paper, the appropriate feed rate can be selected to ensure that the  Ra < 2 μm and a large residual compressive stress is obtained

Research on Energy Saving and Environmental Protection Management Evaluation of Listed Companies in Energy Industry Based on Portfolio Weight Cloud Model

Under the background of the “carbon peaking and carbon neutrality” strategy, energy saving and environmental protection (ESEP) management has become one of the most important projects of enterprises. In order to evaluate the ESEP management level of listed companies in the energy industry comprehensively, this study puts forward the evaluation framework of “governance framework-implementation process-governance effectiveness” for ESEP management level. Based on the comprehensive collection and collating of related information reports (e.g., sustainable development reports) of listed energy companies from 2009 to 2018, the ESEP information was extracted, and the portfolio weight cloud model was used to evaluate the ESEP management status of listed energy companies in China. It is of great theoretical innovation and practical significance to promote the evolution of the economy from “green development” to “dark green development”. The results show that: (1) the number of SHEE information released by listed companies in the energy industry shows a steady increasing trend, but the release rate is low, and there are differentiation characteristics in different industries. (2) The ESEP management level of most listed companies in the energy industry is still at the low level, and only 17.19% (S = 65) of the sample companies are at the level of “IV level-acceptable” and “V level-claimable”. (3) In terms of governance framework-implementation process-governance effectiveness, B1-governance framework (Ex = 3.4451) and B2-implementation process (Ex = 2.9480) are relatively high, but B3-governance effectiveness (Ex = 2.0852) and B4-public welfare (Ex = 2.0556) are relatively low. The expectation of most ESEP evaluation indexes fluctuates between “III level-transition level” and “II Level-improvement level”. Finally, some suggestions are put forward to improve ESEP management levels

Relationships between Bridge Foil Parameters and Input Pulse Current

AbstractThe electrical exploding of a bridge foil consists of four stages: solid, liquid, gas and plasma. Most of the energy absorbed by the bridge foil comes from joule heating; therefore, it is great important to study the influence of the parameters of the bridge foil on its electrical exploding process. In order to improve the energy efficiency of the exploding foil initiation system (EFIs) and obtain the relation between the bridge foil parameters and input pulse current, the deposited energy and the peak power in the process of electrical explosion of square waveform bridge foil was investigated. The result of this study could provide guidance for the optimization design of exploding foil initiation system

Ecological assessment of phytoplankton community via microscopic method and 18S rRNA gene sequencing in Pearl River Estuary

Monitoring phytoplankton community underpins our understanding of water quality and ecological functions. In this study, we approached phytoplankton abundance, community composition, and diversity by both microscopy and 18S rRNA gene sequencing. Environmental variances influencing the phytoplankton were evaluated as well. There were 6 phyla and 62 species identified by microscopy, and the diversity index Shannon-Wiener and evenness index Pielou index indicated phytoplankton community had high diversity; however, the high density of dominance genus suggested that our research region had potential red tide effects. The canonical correspondence analysis illustrated that suspended solids, phosphate and temperature were three major factors that affected the distribution and components of phytoplankton community. The DNA barcoding sequencing of 18S rRNA gene supported the main results via microscopic methods while providing more identified community components, which implied that 18S rRNA gene sequencing can be used as a supplemental method for fast ecological assessment of phytoplankton community

Measurement of Creep Stress Exponent of TC17 Titanium Alloy by Nanoindentation Method at Room Temperature

The creep stress exponent is commonly employed to characterize the deformation mechanism during the steady-state creep stage, serving as an indicator of creep behavior. The creep phenomenon of high melting point metallic materials is not obvious at room temperature. However, the nanoindentation method proves suitable for investigating the creep properties of metallic materials under such conditions. Consequently, this paper places emphasis on measuring the creep stress exponent of TC17 titanium alloy at room temperature using the load preservation stage of the nanoindentation method with a constant loading rate. In order to investigate the effects of loading rate and maximum load on the experimental results, different loading rates were applied to the diamond Berkovich indenter to reach different maximum loads. The indenter was held under the maximum load for a duration of 360 s, and the relationship between the indentation strain rate and indentation stress during the holding process was used to obtain the creep stress exponent of the material at room temperature. The findings indicate that within the loading rate range of 1.25 to 15 mN/s and maximum load range of 50 to 300 mN, the influence on the experimental results is insignificant. Ultimately, the distribution range of the creep stress exponent for TC17 titanium alloy at room temperature was measured to be 8.524–8.687

Research on Energy Saving and Environmental Protection Management Evaluation of Listed Companies in Energy Industry Based on Portfolio Weight Cloud Model

Under the background of the &ldquo;carbon peaking and carbon neutrality&rdquo; strategy, energy saving and environmental protection (ESEP) management has become one of the most important projects of enterprises. In order to evaluate the ESEP management level of listed companies in the energy industry comprehensively, this study puts forward the evaluation framework of &ldquo;governance framework-implementation process-governance effectiveness&rdquo; for ESEP management level. Based on the comprehensive collection and collating of related information reports (e.g., sustainable development reports) of listed energy companies from 2009 to 2018, the ESEP information was extracted, and the portfolio weight cloud model was used to evaluate the ESEP management status of listed energy companies in China. It is of great theoretical innovation and practical significance to promote the evolution of the economy from &ldquo;green development&rdquo; to &ldquo;dark green development&rdquo;. The results show that: (1) the number of SHEE information released by listed companies in the energy industry shows a steady increasing trend, but the release rate is low, and there are differentiation characteristics in different industries. (2) The ESEP management level of most listed companies in the energy industry is still at the low level, and only 17.19% (S = 65) of the sample companies are at the level of &ldquo;IV level-acceptable&rdquo; and &ldquo;V level-claimable&rdquo;. (3) In terms of governance framework-implementation process-governance effectiveness, B1-governance framework (Ex = 3.4451) and B2-implementation process (Ex = 2.9480) are relatively high, but B3-governance effectiveness (Ex = 2.0852) and B4-public welfare (Ex = 2.0556) are relatively low. The expectation of most ESEP evaluation indexes fluctuates between &ldquo;III level-transition level&rdquo; and &ldquo;II Level-improvement level&rdquo;. Finally, some suggestions are put forward to improve ESEP management levels

Data on microbial community composition of sludge from high altitude wastewater treatment plants determined by 16S rRNA gene sequencing

This work presented the sequences of activated sludge from two municipal wastewater treatment plants (WWTPs) located in a high altitude Plateau in Tibet, China (∼3650 m above the sea level). Sequencing data are the 16S rRNA gene amplicons of V4V5 region that sequenced on an Illumina HiSeq PE250 platform. Data presented here include detail description and water quality parameters of the WWTPs as well as results of 16S rRNA gene sequences from their active sludges. The core microbial communities in the WWTPs were shown at the taxonomic level of phylum, class, order, family, genus and species. The sequencing data have been deposited in NCBI BioProject PRJNA477990 with the Biosample accessions SAMN09488330-SAMN09488338. The annotation of OTU table at the genus level was assessable on Zenodo (https://zenodo.org/record/2105899#.XA0vQPZuJyw)