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In the aviation and weapon industry, aluminum alloy thin-walled workpieces are widely used, and milling is a common manufacturing process for these thin-walled workpieces. In milling, many burrs generate on the entrances and exits of workpiece edges and the tops of slot on workpiece surface, which affect machining quality and assembly accuracy and produce more seriously tip discharge effect. To investigate the burr formation mechanism, an analyzed model of top burr thickness considering the tool deflection angle and workpiece deformation is proposed to elaborate the burr formation process in milling of thin-walled workpiece. In this process, top burr formation process is analyzed, and the burr thickness is expressed by the motion relationship between cutting tools and workpieces. Then, based on energy theory, a top burr thickness predicted model considering the tool deflection angle and workpiece deformation in milling of aluminum alloy thin-walled workpiece is proposed. Subsequently, under the determined milling condition, the top burr thicknesses are calculated for verification. Finally, several milling experiments are carried out for validating the feasibility and effectiveness of the proposed model. Experimental results show that the predicted top burr thicknesses are in good agreement with the measured value in milling, and the prediction accuracy of the top burr thickness by the proposed model reached 96.5%. [ABSTRACT FROM AUTHOR]

Facial information plays an important role in human communication, e.g., rich and nuanced facial expressions effectively convey emotions. Traditional data such as 2D facial images and videos are susceptible to perturbation from lighting and occlusion, while 3D static data such as mesh models lack the temporal information which is necessary to describe facial dynamics. Therefore, researches on 4D facial data (3D facial models together with time as the fourth dimension) have received considerable attention in recent years. 4D data can simultaneously reflect the complex facial temporal and space information. To fully explore these characteristics, we present a systematic overview of the 4D facial research in this paper. We give a review in terms of historical development of 4D facial datasets, acquisition process of these datasets, related algorithms and applications, and discussion of outstanding issues. We also analyze the 4D facial research works by summarizing and comparing them; in particular, we present the results on three kinds of tasks conducted on the 4D facial datasets, i.e., expression-related tasks (AU detection, expression recognition and retrieval), generation tasks (3D facial reconstruction, facial expression and facial animation generation), and other tasks (facial registration, facial recognition and facial disease diagnosis). Finally, we summarize the future research directions. [Display omitted] • We provide a comprehensive overview of a 4D facial dataset. • We classified and elaborated on the different facial studies conducted using 4D facial datasets. • We summarize the future research direction. [ABSTRACT FROM AUTHOR]

High-speed motorized spindle is an important component of machine tool, and the influence of heat and deformation generated in the working process on the machining accuracy cannot be ignored. In order to reduce the temperature of the motorized spindle in the machining process, this paper first explores the influence of the flow rate of the motorized spindle cooling water on the cooling water jacket and the overall temperature change. The results indicate that when the flow rate exceeds a certain range, the overall temperature no longer drops, so there is an optimal flow rate in the choice of flow rate. Secondly, to solve the problem of uneven axial temperature distribution of the traditional spiral water jacket, four kinds of cooling water jackets with different structures were proposed. The simulation results show that the difference in temperature distribution inside the serpentine water jacket is small, the overall temperature was reduced by 1.8 °C and the pressure drop was reduced by 62.54 kPa. It shows that the serpentine cooling water jacket has better cooling performance and can effectively reduce the thermal deformation of the motorized spindle shafting, so as to achieve the purpose of improving the machining accuracy. [ABSTRACT FROM AUTHOR]

In this study, we explored the regulatory mechanism of intervertebral disc degeneration (IDD) that involves miR-31 shuttled by bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) and its downstream signaling molecules. Nucleus pulposus cells (NPCs) were isolated and treated with TNF-α to simulate IDD in vitro. The TNF-α-exposed NPCs were then cocultured with hBMSCs or hBMSC-EVs in vitro to detect the effects of hBMSC-EVs on NPC viability, apoptosis, and ECM degradation. Binding between miR-31 and NFAT5 was determined. A mouse model of IDD was prepared by vertebral disc puncture and injected with EVs from hBMSCs with miR-31 knockdown to discern the function of miR-31 in vivo. The results demonstrated that hBMSC-EVs delivered miR-31 into NPCs. hBMSC-EVs enhanced NPC proliferation and suppressed cell apoptosis and ECM degradation, which was associated with the transfer of miR-31 into NPCs. In NPCs, miR-31 bound to the 3 ′ UTR of NFAT5 and inhibited NFAT5 expression, leading to activation of the Wnt/β-catenin pathway and thus promoting NPC proliferation and reducing cell apoptosis and ECM degradation. In addition, miR-31 in hBMSC-EVs alleviated the IDD in mouse models. Taken together, miR-31 in hBMSC-EVs can alleviate IDD by targeting NFAT5 and activating the Wnt/β-catenin pathway. [ABSTRACT FROM AUTHOR]

Supported Mn2O3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR). However, its controlled synthesis is challenging when the supporting material is the conventional pure silicon SBA-15 mesoporous molecular sieve. Here we show that silicon and aluminium in fly ash, the solid waste produced by coal-fired power plants, can be used to synthesize an Al-SBA-15 mesoporous molecular sieve support, which can guide the growth of Mn2O3 in the as-synthesized Fe-Mn/Al-SBA-15 NH3-SCR catalyst. Its superior catalytic performance is demonstrated by the high NOx conversion (≥90%) and selectivity (≥86%) at low temperatures (150–300 °C). The combined theoretical and experimental results reveal that the introduction of Al induces the growth of Mn2O3 catalysts. Our findings, therefore, provide a strategy for the rational design of low-temperature NH3-SCR catalysts through dopant-induced component engineering of composite materials. Low-temperature manganese-based denitrification catalysts require a balance between high reduction reactivity and selectivity. Here aluminium in a mesoporous molecular sieve induces the growth of manganese oxide to obtain an iron-manganese catalyst which achieves high efficiency at temperatures of 150–300 °C. [ABSTRACT FROM AUTHOR]

Abstract The catalytic performance of Hg0 oxidation over vanadium-based SCR catalysts modified by different addition amounts of CuO was investigated. All catalysts were prepared by impregnation method and characterized. The 7% Cu/VWTi exhibited high Hg0 oxidation as well as a desired NO removal efficiency at 280–360 °C. The characterization revealed the enhancement of redox properties and well-dispersed active species results in the high catalytic performance after modification. The incorporation model showed that CuO in 7% Cu/VWTi was present in the monolayer dispersion, leading to the highest performance. Moreover, the effects of O 2 , NO, SO 2 , NH 3 and HCl were explored. It showed all flue gas except NH 3 could promote Hg0 oxidation. Fortunately, the inhibiting effect of NH 3 could be scavenged if the catalyst is installed at the downstream of the SCR reactor. In addition, the mechanism of Hg0 oxidation over Cu/VWTi was discussed. Graphical abstract The Hg0 oxidation by HCl on Cu/VWTi followed Eley-Rideal mechanism. Image 1 Highlights • The 7% Cu/VWTi exhibited high Hg0 oxidation as well as a desired NO removal efficiency at 280–360 °C. • CuO in 7% Cu/VWTi was present in the monolayer dispersion, leading to the highest performance. • The CuO dispersion was explained by the incorporation model. • The effects of flue gas compositions on Hg0 oxidation were studied. • The Hg0 oxidation by HCl on Cu/VWTi followed Eley-Rideal mechanism. [ABSTRACT FROM AUTHOR]

Fe and/or Mn/SBA-15 catalysts were prepared by the impregnation method using low-cost fly ash-derived SBA-15 molecular sieve as support and tested towards NH 3 -SCR. Powder XRD, N 2 adsorption, XPS, H 2 -TPR and SEM techniques were used for catalyst characterization and investigation of relationships with the catalytic activity. The Fe-Mn/SBA-15 catalyst exhibited significantly higher NH 3 -SCR activities than Mn/SBA-15 or Fe/SBA-15 in the 150–250 °C range owing to some developed synergistic effects between Mn and Fe. In particular, the addition of Mn improved the dispersion of Fe 2 O 3 on the catalyst surface, while the addition of Fe promoted the formation of single β-MnO 2 phase. The high dispersion of Fe 2 O 3 , the appropriate Mn 4+ /Mn 3+ ratio, the concentration of adsorbed oxygen and the low-T enhanced redox activity of the Fe-Mn/SBA-15 improved its NH 3 -SCR activity. This work opens new avenues of recycling fly ash formed in coal-fired power plants (reducing environmental pollution) and developing low-cost SCR catalysts for NO x pollution control. [ABSTRACT FROM AUTHOR]

Chromium oxide is widely used in national defense, hard alloy, alloy, pigment, vacuum plating, consumables and high purity alloy and belong to one of the main products of chromate production industry. In the present study, a novel cleaner process is proposed to synthesize nanostructure chromium oxide (Cr 2 O 3 ) from waste source containing chromium (VI). Hydrated chromic oxide was prepared by combination membrane and hydrothermal method. After calcined, chromium (III) compound: nanostructure chromium oxide (SNCO) was obtained. In the membrane electrolyte stage, this way can reduce the amount of acid added to adjust the solution pH. Besides, addition of CO 2 into the cathode compartment could improve the current efficiency and desalination efficiency, while decrease the energy consumption. Then the products were characterized. Combined with the experiment results of TGA and XRD, the potential formation mechanism of hydrated chromic oxide was proposed. The fine structure of the product was analyzed by SEM and TEM. It was proved that the nanostructure chromium oxide with good crystallinity was obtained. The UV–Vis was used for optical properties, which proved that it had good optical properties. [ABSTRACT FROM AUTHOR]

The promotional effects of Cu and Fe over the V 2 O 5 -WO 3 /TiO 2 NH 3 -SCR catalyst for the oxidation of Hg 0 and the selective catalytic reduction of NO by NH 3 were investigated in the temperature range of 280–360 °C. Cu or Fe addition, especially Cu, improved the catalytic performance of V 2 O 5 -WO 3 /TiO 2 . The results show that Cu 2 + was the main Cu species in the Cu-containing catalyst, whereas FeVO 4 was formed in the Fe-containing catalyst. Well-dispersed active species, good redox properties and abundant chemisorbed surface oxygen species on the catalyst surface were responsible for the high catalytic performances. Hg 0 oxidation over the V-based catalysts may follow a Mars-Maessen mechanism. [ABSTRACT FROM AUTHOR]

First principles calculations were carried out for α-Al 2 O 3 (0001) surface and γ-TiAl(111)/α-Al 2 O 3 (0001) interface to study the adhesion properties of the interface and to clarify the mechanisms that govern the adhesion of TiAl and its oxidation product Al 2 O 3 . Two type interface models, the TiAl(111) with Al- and O-terminated α-Al 2 O 3 (0001) surfaces denoted as T(A 1 )-type and T(O T )-type interface, respectively, were considered. The Universal Binding Energy Relation (UBER) was used to determine the separation between TiAl and Al 2 O 3 and the work of adhesion of the γ-TiAl(111)/α-Al 2 O 3 (0001) interface. Optimization was then performed for all interfaces considered here using the separation obtained with UBER. The lowest work of adhesion is −1.05 J/m 2 for the T(A 1 )-type interface and is −4.04 J/m 2 for the T(O T )-type interface. There exists competition between O–Ti and O–Al (on the TiAl side) interactions; however O–Al bond is stronger than O–Ti bond because the main body of the Al valences is involved in the hybriding with O p electrons, while only part of the Ti d valence is involved in the O–Ti bonding. Thus the O–Al interaction dominates the adhesion between TiAl(111) and Al 2 O 3 (0001) surfaces, and it can be inferred that an Al-rich TiAl surface will favor the adhesion between TiAl/Al 2 O 3 . [ABSTRACT FROM AUTHOR]

Highlights: [•] A breakthrough technology in sorbent production for CO2 capture has been developed successfully. [•] The sorbent can be synthesized from industrial waste fly ash by using this novel method. [•] The CO2 sorption capacity of the sorbent is highest among these solid amine sorbent derived by fly ash. [•] The preparing process of the solid amine sorbent was simplified. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we report about catalyst deactivation during reactions of 1-pentene over acidic ultrastable Y zeolite in a fixed-bed reactor. The effects of reaction temperature and time-on-stream (TOS) on product distribution, conversion and coke formation are discussed. At this work various coke groups – coke precursors, hard coke as well as total coke amount – were followed with TOS. Furthermore, the effects of coking on 1-pentene reactions were also studied. Cracking and hydride transfer were the predominant reactions in the first minute of TOS which deactivated rapidly allowing isomerisation to become the main reaction afterwards. A steep increase of the amount of coke formed was observed initially which was in good correlation with the initial rapid deactivation. The hydrogen freed during this initial time from the formation of high a carbon-to-hydrogen (C/H) ratio coke components contributed to the formation of hydride transfer products. [Copyright &y& Elsevier]

Abstract: A novel thermogravimetric methodology is introduced to study the characterisation of coke precursors. The effect of different reactants, time on stream, and reaction temperature on coke precursor formation and chemical characterisation was investigated. This allowed us to classify coke precursors into “small” and “large” ones. Coke precursors are formed preferentially on the strongest acid sites at a rapid rate, with fast further transformation to other coke species. Furthermore, the method revealed a maximum of large coke precursors with time on stream due to their fast transformation into hard coke over strong acid sites compared with the much slower formation from small coke precursors over weak acid sites. [Copyright &y& Elsevier]

Coppicing is a highly effective method of producing a great deal of fast growing, sustainable timber without the need for replanting. Tamarix chinensis , a native salt-tolerant species, plays an important role in the ecosystems of arid saline alkali soil and coastal wetlands in northern China. In this study, we conducted a coppicing field experiment on T. chinensis to study the vigor of resprouting over a 4-year monitoring period in the coastal wetland of Laizhou Bay, China. Results of this study show that the growth of coppiced T. chinensis was vigorous and conformed to an "S-curve" type growth pattern. The height and crown of coppiced T. chinensis recovered quickly to the initial level by the 2nd year of regrowth and its aboveground biomass regained 93.5% of the previous level by the 4th year. The carbon stock in the T. chinensis wetland was significantly increased by the coppicing operation. Carbon stocks in the aboveground parts and soil (0–100 cm) increased by 222.6 g m−2 and 588.9 g m−2, respectively, during the 4-year experimental period. These values are 43% and 74% higher, respectively, than those in the control plot over the same period. These results indicate that coppicing provides a practical means for promoting regeneration and rejuvenation of Tamarix spp. forests as well as a new approach to increasing biomass and carbon stocks in the coastal wetlands of northern China. [ABSTRACT FROM AUTHOR]

The electrochemical NRR, which can be driven by renewable energy sources, is an emerging strategy for addressing the high energy consumption and CO 2 emission issues caused by the traditional Haber–Bosch ammonia synthesis technique. FePc catalyzes the electrochemical ammonia synthesis reaction well, but intermolecular π-stacking and multi-layer overlapping lead to low NH 3 yields. Here, [Bmim][Cl] and [Bmim][NTF 2 ] ILs were used to induce monolayer dispersion of FePc. Ionic-liquid-induced FePc electrocatalyst, namely FePc/C-700, which was constructed with ILs as the carbon source, gave an excellent NH 3 yield (24.25 μg mg cat −1 h−1) and Faradaic efficiency (30.59%) at − 0.1 V. The formation of a monolayer FePc structure was confirmed by HAADF-STEM and XANES. The results of DFT calculations and NRR experiments showed that the monolayer FePc structure promoted N 2 adsorption and inhibited the competitive HER. These results will be useful in the design of active sites of layered macromolecules to achieve efficient electrochemical NRR. [Display omitted] • The monolayer FePc/C-700 catalysts successfully synthesized in this work exhibits excellent catalytic activity in the NRR. • Using ILs to induce monolayer dispersion of FePc and as carbon sources to suppress the formation of multi-layer FePc structure • This work proves that the formation of the multi-layer FePc structure affects the activation of N 2. [ABSTRACT FROM AUTHOR]

Suppressing thermal deformation is an effective measure to reduce the thermal error of CNC (computer numerical control), and the machining accuracy of CNC directly determines the quality and accuracy of parts. A cooling pipe is designed for the non-heat source parts with large swing head deformation to restrain its thermal deformation. At present, there is a lack of research results in this field. Through the finite element simulation analysis of 5AS01 five-axis direct drive swing head, the thermal deformation of swing head and motorized spindle is compared. It has been determined that the thermal deformation of the shell in the Z- and X-axes has a significant impact on the precision of the swing head's machining; thus, steps must be taken to limit its deformation. The cooling position was determined by simulating the normal working condition of the shell and gray correlation analysis. Capillary copper tube was connected with water-cooling system for cooling, and the heat transfer performance between the shell and copper tube was improved by using heat conductive silica gel sheet. Comparing the shell cooling simulation with the shell cooling experiment, it is found that both of them have the same trend in restraining the thermal deformation of the shell, reducing the thermal deformation in X direction by more than 50% and in Z direction by more than 24%. It verifies the accuracy of the cooling simulation model and the effectiveness of this cooling method, which can effectively reduce the thermal deformation of the shell and improve the machining accuracy of the machine tool. [ABSTRACT FROM AUTHOR]

In order to solve the problem that thermal deformation of CNC machine tools affects machining accuracy, a simulated internal cooling structure based on external copper tube is studied. Method of reducing thermal error of machine tool by cooling temperature sensitive position. Taking 5AS01 double swing angle milling head as the research object, the finite element simulation of temperature field and deformation field is carried out through three-dimensional modeling. It is analyzed that the thermal deformation of the swing head shell in X- and Z-directions has great influence on the thermal error of the motorized spindle, so the cooling of its temperature-sensitive position is studied. The thermal distribution of the shell under normal working conditions was simulated statically, and four temperature-sensitive positions were selected from 10 temperature measuring points by grey relational analysis. The straight capillary copper tube combined with thermal conductive silica gel was used for liquid cooling. Experiments show that the thermal deformation of the shell can be effectively reduced by about 50% by cooling the temperature sensitive points, which provides a reference for the optimization of the structure of the pendulum, and indirectly improves the machining accuracy of the motorized spindle, thus improving the machining accuracy of the machine tool. [ABSTRACT FROM AUTHOR]

The Indian Ocean Dipole (IOD) is the predominant interannual climate mode and is critical in regulating the biogeochemical cycles of the equatorial Indian Ocean (EIO). However, the dynamics of nutrient supply and the magnitude of biological responses are less understood. Here, by comparing the biophysical in situ observations across the eastern EIO during the decaying period of a positive IOD in 2019 and neutral condition in 2017, we identify that the shoaling thermocline, initiated by reinforced easterly wind, lifts the nutricline into the euphotic layer under positive IOD condition. Coincidently, the strong turbulent mixing induced by the shear instability between the opposite‐flowing surface current and subsurface Equatorial Undercurrent increases the upward turbulent nutrient flux into the euphotic zone. Their combined effect triggers a vigorous subsurface biological response over the eastern EIO, with approximately twofold higher integrated chlorophyll‐a contents in the water column during a positive IOD than under neutral condition. Plain Language Summary: The availability of nutrients in the sunlit layer is the main factor limiting microalgae growth, which is the primary producer of marine ecosystems. Particularly in the tropical oceans, strong stratification due to warm and less salty surface water inhibits nutrient replenishment from the deep layer, leading to weak seasonality in primary production. With the occurrence of climate variability, for example, the Indian Ocean Dipole (IOD), an ocean‐atmosphere coupled climatic phenomenon, can significantly impact the biogeochemistry and ecosystem in the equatorial Indian Ocean (EIO). However, high‐resolution in situ observations, which can reveal the mechanism of nutrient supply and biological response under IOD conditions, are still lacking. We show that the combined effect of thermocline shoaling and subsurface turbulent mixing triggered an apparently elevated nutrient supply and a subsequent robust subsurface biological response in the eastern EIO during the decaying period of an extreme positive IOD in 2019. This study may aid in understanding the evolution of marine ecosystems during the greenhouse warming era. Key Points: A biological subsurface eastern equatorial Indian Ocean was observed during decaying period in a positive Indian Ocean Dipole (pIOD)The shoaling thermocline driven by reinforced easterly wind lift the nutricline into the euphotic layer in the pIOD phaseIncreased turbulent nutrient flux is caused by vertical shear due to the opposite‐flowing surface current and Equatorial Undercurrent [ABSTRACT FROM AUTHOR]

High-speed electric spindle is an important part of computer numerical control (CNC) machining equipment. The thermal displacement generated by the electric spindle during operation is the main reason that affects the machining stability and machining accuracy of the electric spindle. Compensating the thermal error of the high-speed electric spindle can effectively improve the CNC machining. Improve equipment processing performance. Therefore, it is particularly important to establish the accuracy of the thermal error prediction model. Taking the A02 high-speed electric spindle as the research object, ANSYS is used to analyze the thermal characteristics of the electric spindle, and the temperature and thermal displacement monitoring points of the electric spindle are arranged according to the simulation results, and the temperature and thermal displacement data of the monitoring points under different rotational speeds are collected; using K-means to classify temperature measurement points, uses the gray relation analysis degree to determine the correlation between the temperature measurement point and the thermal displacement data, and selects 4 temperature-sensitive points from 10 temperature measurement points. Finally, particle swarm optimization (PSO) is used to optimize the penalty factor and kernel function of support vector machine (SVM), and the PSO-SVM prediction model is established to compare with the neural network prediction model of SVM and genetic algorithm (GA) optimized SVM. The results show that PSO-SVM has better robustness, stability, and generalization ability. [ABSTRACT FROM AUTHOR]

In recent years, one type of alumina rich fly ash (ARFA) with about 50 wt% of alumina has been extensively investigated for alumina extraction in China. Due to the silica in ARFA, alumina extraction would have to generate a huge amount of solid waste. There is a growing interest in the glasses in ARFA, because they are composed mainly of silica and could be removed prior to alumina extraction. In this work, the glasses in ARFA have been investigated by chemical methods, that is, acid and base digestions. The chemical compositions have been measured by XRF for ARFA from the digestion processes. The K2O standard, XRD, and FTIR spectroscopies were successfully used to define the digestions processes, and size analysis and SEM-EDX provided rich information on particle transformations. As a result, acid and base digestion methods were found to produce very similar results for the glasses in ARFA. The K2O standard was attributed to the formation of glasses by illites, and TiO2 and Fe2O3 were proposed to originate from ilmenite in alumina rich coals (ARC). Some implications of the results were also discussed for the alumina extraction from ARFA. [ABSTRACT FROM AUTHOR]

The thermal error of the motorized spindle is an essential factor affecting the machining accuracy of high-speed numerically controlled machines. The establishment of a high-speed motorized spindle thermal error model for thermal error compensation can effectively improve the impact of thermal errors on the machining accuracy of the machine tool. This paper proposes a sparrow search algorithm to optimize the Elman neural network to predict thermal errors in motorized spindles. First is the simulation analysis on thermal characteristics of A02 high-speed motorized spindle. Based on the simulation results, the position of the temperature measuring points is arranged in the temperature and thermal error experiment of the motorized spindle. The temperature and thermal displacement data of high-speed motorized spindle at different rotational speeds were collected; secondly, the method of combining pedigree clustering and k-means clustering is used to perform cluster analysis on each temperature measurement point, and the grey correlation degree is used to determine the correlation between temperature measurement points and thermal error. Three temperature-sensitive points were screened from ten temperature measurement points, which reduced the collinearity between temperature measurement points and the number of independent variables of the model. Finally, the weights and thresholds of the Elman neural network are optimized by the sparrow search algorithm, and the thermal error prediction model of motorized spindle based on SSA-Elman neural network is established and compared with Elman neural network and Particle Swarm Optimized Elman Neural Network prediction model. The results show that the SSA-Elman neural network model has the highest prediction accuracy and exhibits good stability and generalization ability. [ABSTRACT FROM AUTHOR]

Abstract: Calcined Mg/Al hydrotalcite (CH-Mg/Al) and calcined Mg/Al vanadate hydrotalcite (CHV-Mg/Al) were prepared and characterized. Adsorption kinetics, effect of pH, equilibrium isotherms and the selectivity of both absorbents were assessed. The removal mechanism was studied by XRD, XPS and FTIR. The results showed that there was no redox reaction during the adsorption process. The adsorption process of CH-Mg/Al was mainly anion exchange and adsorption on external surface of the layers. The adsorption capacity of CHV-Mg/Al was mainly caused by ion exchange. The calcined Mg/Al hydrotalcite showed wonderful vanadium (V) adsorption capacity. Using vanadate to synthesize hydrotalcite was unfavorable to removal of vanadium (V) from aqueous solution. CHV-Mg/Al had highly selectivity of vanadium (V) in the mixed solution of vanadate and dichromate. Calcined hydrotalcites material has potential application for the removal of vanadium (V) from aqueous solution. [Copyright &y& Elsevier]

With continued urbanization in China, the construction of urban gas pipelines is increasing, and the safety of gas pipelines are also increasingly affected by urban development and the increased scope of buildings and roads. Pipes with defects are more likely to fail under the surface loads. In this study, uniaxial tensile tests of high-density polyethylene (HDPE) pipes were carried out to obtain the real material parameters of pipe. A pipeline-soil interaction finite element model of HDPE pipeline with defects under surface load was established. The failure mechanism of the urban gas pipeline was studied and the influence of parameters such as internal pressure, defect position, defect depth on the mechanical behavior, and failure of pipelines were analyzed. A failure criterion for HDPE pipes with defects under surface load was proposed based on the limit-state curves obtained under different working conditions. Furthermore, an accurate and efficient fitness-for-service assessment procedure of pipes with defects under surface load was proposed. The results showed that maximum Mises stress of the pipeline gradually increased with increasing surface load and the position of maximum stress changed from the top and bottom of the pipe to the defect position and both sides of the pipe. Finally, when Mises stress of the HDPE pipe exceeds the yield limit, failure will occur. Internal pressure, defect location, and defect depth were found to influence the failure process and critical surface load of the pipeline. Safety evaluation curves of the gas pipeline with defects under surface load were obtained by calculating the critical failure load of the pipeline under various working conditions. Finally, a nonlinear fitting method was used to derive a formula for calculating the critical surface load under different defect parameters. The proposed method provides a useful reference for urban gas pipeline safety management. [ABSTRACT FROM AUTHOR]

Marine blue holes are precious geological heritages with high scientific research values. Their physical and chemical characteristics are unique because of the steep-walled structure and isolated water column which create isolated ecosystems in geographically restricted areas. The Sansha Yongle Blue Hole (SYBH) is the world's deepest marine blue hole. Here, we generated the first DNA metabarcoding dataset from SYBH sediment focusing on foraminifera, a group of protists that have colonized various marine environments. We collected sediment samples from SYBH along a depth gradient to characterize the foraminiferal diversity and compared them with the foraminiferal diversity of the costal Jiaozhou Bay (JZB) and the abyssal Northwest Pacific Ocean (NWP). We amplified the SSU rDNA of foraminifera and sequenced them with high-throughput sequencing. The results showed that the foraminiferal assemblages in SYBH were vertically structured in response to the abiotic gradients and diversity was higher than in JZB and NWP. This study illustrates the capacity of foraminifera to colonize hostile environments and shows that blue holes are natural laboratories to explore physiological innovation associated with anoxia. [ABSTRACT FROM AUTHOR]

In the previous decade, neonicotinoids (NEOs) and fipronil (FIP) have received increasing attention as environmental pollutants because the high toxicity of these insecticides to nontarget arthropods has been recognized. In this study, a new method was developed for the simultaneous determination of seven NEOs and FIP and its metabolites (FIPs) in seawater and river water samples using disk-based solid-phase extraction (SPE) and high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). The optimization of disk-based SPE extraction and HPLC separation parameters of target analytes was investigated. Under optimal conditions, the low limit of quantitation (LOQ) of 11 target analytes in actual water samples ranged from 0.05 ng/L to 0.50 ng/L. Satisfactory absolute recoveries (58.9%–109.9%), precision (relative standard deviations, ≤13.3%), and linearity (R 2 ≥ 0.995) were also achieved, thereby indicating that the developed method would be suitable to determine the target NEOs and FIPs in seawater and river water. Finally, the proposed method was applied to determine the amounts of these insecticides in authentic environmental water samples collected from Jiaozhou Bay, China, and its adjacent rivers. Nitenpyram, thiamethoxam, imidacloprid, clothianidin, and acetamiprid were detected, as well as FIPs in seawater and river water samples. This study is the first to report that NEOs and FIPs are detected in the coastal seawater. The total concentration of these insecticides ranged from ≤LOD to 11.19 ng/L, which indicates that these pesticides are eventually discharged into the marine environment. Therefore, it is necessary to investigate the temporal spatial distribution, migration and transformation, environmental fate, and bioavailability of these pesticides in further studies. Image 1 • SPE disk had favorablerecoveries for simultaneous enrichment of trace NEOs and FIPs. • A reliable analytical method was developed for NEOs and FIPs in water samples. • Several NEOs, FIP, and its metabolites were detected in Jiaozhou Bay coastal water. • The analysis of NEOs and FIPs in seawater was reported for the first time. • More attention has to be focused on environmental risks of the coastal area posed by NEOs and FIPs. [ABSTRACT FROM AUTHOR]

• Hexagonal WO 3 with (0 0 1) exposed facet has higher activity than that with (1 0 0). • More coordinative unsaturated W6+ atoms generate more acid sites on (0 0 1) facet. • Lattice match between V 2 O 5 and WO 3 exposed facets influences vanadate dispersion. • Higher proportioned V4+ and chemisorbed O2− exist on V/H-110 catalyst. • More polymeric vanadates facilitate NH 3 -SCR reaction on V/H-110 catalyst. Hexagonal WO 3 crystals with [1 1 0] and [0 0 1] orientations (denoted as H-110 & H-001) were synthesized and impregnated with 5 wt% V 2 O 5 for NH 3 -SCR catalysis. H-110 with dominant (0 0 1) exposed facet possesses 72% NO x conversion at 400 °C while H-001 with dominant (1 0 0) exposed facet only achieves 17%. The maximal NO x conversion over V/H-110 and V/H-001 catalysts was enhanced to 96% and 47%, respectively. The catalysts were characterized by H 2 temperature-programmed reduction (TPR), temperature-programmed desorption (TPD) of NH 3 , X-ray photoelectron spectroscopy (XPS), Raman, ultraviolet-visible (UV-vis) and diffuse reflection infrared Fourier transform (DRIFT) spectroscopy. The more coordinative unsaturated W6+ atoms on (0 0 1) facet generated more acid sites and NH 3 was more strongly adsorbed on H-110 surface. The better match relationship between vanadia and WO 3 (0 0 1) exposed facets led to the formation of more polymeric vanadates on V/H-110 catalyst. The higher proportioned V4+ and chemisorbed oxygen on V/H-110 catalyst also facilitated NH 3 -SCR reaction. [ABSTRACT FROM AUTHOR]

• Nb 2 O 5 addition improves the sulfur resistance of CeWTi catalyst in presence of H 2 O. • Ammonium hydrogen sulfate is preferentially formed on NbCeWTi catalyst. • More Ce x+ active sites are preserved from attack of SO x with niobia modification. • NO adsorption and nitrate formation are ensured on NbCeWTi in the presence of SO 2. CeO 2 /WO 3 -TiO 2 (CeWTi) and Nb 2 O 5 -CeO 2 /WO 3 -TiO 2 (NbCeWTi) catalysts were prepared by a sol-gel precipitation method. Both the catalysts exhibit high selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) activities at 270–500 °C. The sulfur tolerances of the catalysts were evaluated at 270 °C by adding H 2 O and SO 2 in the feeding gas and NbCeWTi exhibited a significantly improved resistance. The thermogravimetric (TG) and mass spectrographic (MS) results indicated that much less sulfates formed on NbCeWTi and existed mainly in the form of ammonium hydrogen sulfate species which protected Ce x+ active sites effectively from attacking of SO 2. According to the results of temperature-programmed desorption of ammonia (NH 3 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and SO 2 oxidation, loading niobia on CeWTi inhibited the SO 2 oxidative adsorption and SO 3 production which basically reduced sulfur poisoning of the catalyst. Additionally, the niobia modification ensured the formation of nitrates from the competitive adsorption of SO 2 and hereby facilitated the nitrate SCR route based on the in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS). [ABSTRACT FROM AUTHOR]

Protein-like substances produced by biochemical reactions after disinfection of Zooplankton like Cyclops and humic substances in natural water are the main components of NOM (Natural organic matter). To eliminate early warning interference in the fluorescence detection of organic matter in natural water, a clustered flower-like AlOOH (aluminum oxide hydroxide) sorbent was prepared. HA (humic acid) and amino acids were selected as mimics of humic substances and protein-like substances in natural water. The results demonstrate that the adsorbent can selectively adsorb HA from the simulated mixed solution and restore the fluorescence properties of tryptophan and tyrosine. Based on these results, a stepwise fluorescence detection strategy was developed and used in natural water rich in zooplanktonic Cyclops. The results show that the established stepwise fluorescence strategy can well overcome the interference caused by fluorescence quenching. The sorbent was also used for water quality control to enhance coagulation treatment. Finally, trial runs of the water plant demonstrated its effectiveness and suggested a potential control method for early warning and monitoring of water quality. [Display omitted] • Adsorption pre-treatment proposed to improve fluorescence monitoring accuracy. • Selective adsorption of adsorbents with flower-like cluster structures. • Investigation of the mechanism of protein quenching in natural water. • Adsorption coagulation has promising applications in practical water treatment. [ABSTRACT FROM AUTHOR]

Paralytic shellfish toxins (PSTs) producing algae are widely distributed in the global coastal aquatic environment, posing a threat to coastal ecosystem health and mariculture safety. However, the levels and potential environmental risks of PSTs frequently detected in shellfish remain largely unexplored in seawater of mariculture zones. In this study, a new method for trace detection of 13 common PSTs (<1.0 ng/L) in seawater was established based on off-line solid phase extraction (SPE) and on-line SPE-liquid chromatography-tandem mass spectrometry (on-line SPE-LC-MS/MS), and a systematic investigation of PSTs in seawater of the Laizhou Bay, a typical aquaculture bay in China, was conducted to understand their pollution status, environmental impact factors and ecological risks for the first time. Eleven PSTs were detected in the seawater of Laizhou Bay with total concentrations ranging from 0.75 to 349.47 ng/L (mean, 176.27 ng/L), which indicates the rich diversity of PSTs in the mariculture bay and demonstrates the reliability of the proposed analytical method. C1, C2, GTX2, GTX3, dc GTX2, and dc GTX3 were found to be the predominant PSTs, which refreshed the knowledge of PST contamination in the coastal aquatic environment. PST levels in seawater exhibited the highest levels in the southeastern mouth of Laizhou Bay and decreased toward the inner bay. Correlation analyses showed that climatic factors, nutrient status and hydrological conditions had significant effects on the distribution of PST in mariculture bay. Preliminary environmental risk assessments revealed that aquatic organisms throughout the waters of Laizhou Bay are at risk of chronic PST toxicity. These findings imply that the risk of PST in seawater of mariculture bay has previously been grossly underestimated, and that the coastal aquatic environment in North China and even the world may be at more serious risk of PST pollution, which should be taken seriously. [Display omitted] • A new analytical method was developed for 13 trace PSTs in seawater (<1.0 ng/L). • Various PSTs widely distributed in nearshore water was reported for the fist time. • GTXs, dc GTXs, and C-toxins are the predominant PSTs in mariculture seawater. • Aquatic organisms in the Laizhou Bay are generally at risk of chronic PST toxicity. • Nutrient and hydrological conditions affect the distribution of PST in Laizhou Bay. [ABSTRACT FROM AUTHOR]

Focusing on the diversity, complexity and uncertainty of the third-party damage accident, the failure probability of third-party damage to urban gas pipeline was evaluated on the theory of analytic hierarchy process and fuzzy mathematics. The fault tree of third-party damage containing 56 basic events was built by hazard identification of third-party damage. The fuzzy evaluation of basic event probabilities were conducted by the expert judgment method and using membership function of fuzzy set. The determination of the weight of each expert and the modification of the evaluation opinions were accomplished using the improved analytic hierarchy process, and the failure possibility of the third-party to urban gas pipeline was calculated. Taking gas pipelines of a certain large provincial capital city as an example, the risk assessment structure of the method was proved to conform to the actual situation, which provides the basis for the safety risk prevention. [ABSTRACT FROM AUTHOR]

A NbO x /Ce 0.75 Zr 0.25 O 2 (NbCZ) catalyst was synthesized by a citric acid-aided sol-gel method. It shows that above 80% NO x conversion and above 95% N 2 selectivity for the selective catalytic reduction of NO x by ammonia over this catalyst are achieved in the temperature range 200–450 °C. Based on the DRIFTS and kinetic studies over NbCZ and Ce 0.75 Zr 0.25 O 2 , the promotion mechanism by niobia loading was elucidated with an overall reaction pathway. Two different reaction routes, “L-H” mechanism via “NH 4 NO 3 + NO” at low temperatures (<200 °C) and “E-R” mechanism via “NH 2 + NO” at high temperatures (>350 °C), are presented. The niobia addition increases the surface acidity and promotes the formation of nitrates species at low temperatures. In this way, the reaction between the ads-NH 3 and nitrates species is accelerated to form NH 4 NO 3 intermediates, which then decompose to N 2 and H 2 O. The reaction of the ads-NH 3 species with gaseous NO x at high temperatures is also promoted due to the enhanced acidity and weakened thermal stability of nitrates after niobia loading. [ABSTRACT FROM AUTHOR]

Coal fly ash (CFA), is a by-product of coal combustion which has been regarded as a recalcitrant solid waste. In this work, an effective and low-cost high alumina coal fly ash catalyst was synthesised by using of high alumina coal fly ash and Fe(II)/Fe(III) oxide and the catalytic capacity of o-methyl phenol (OMP) in the Oxidative degradation was investigated. XRD, SEM and XPS were used to characterize the catalyst and the results indicated that the Fe(II)/Fe(III) oxide was successfully introduced. The character results showed that the surface area of CFA increased with increasing the loading content of the Fe(II)/Fe(III) oxide and the biggest surface area is about 69.3 m 2 /g with the loading content of 15 wt.%. The degradation experiment results showed that the catalytic ozonation capacity was affected by the loading of Fe(II)/Fe(III) oxide and the solution pH. The biggest removal efficiency of OMP and the reveal rate of COD were 100.0% and 44.5% which appeared at pH of 11 with the loading content of Fe(II)/Fe(III) oxide of 15 wt.%. The kinetic study of the catalytic ozonation degradation process revealed that the degradation process follows the first order kinetic model. It is indicats that the degradation process of OMP was derived from the heterogeneous Fenton process and affected by the solution pH. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation was used to study the adsorption of single wall carbon nanotubes (SCNT) in levofloxacin (LEV) solutions of different concentrations by Radial distribution function, mean square displacement and interaction energy. The results showed that levofloxacin molecules were adsorbed around the carbon nanotubes. The adsorption effect of large concentration solution was not as good as that of low concentration solution because of agglomeration. LEV molecules with different concentration were free diffusion within 15ns, and gradually agglomerated under the influence of adsorption. The energy change is proportional to the concentration of the molecule. The distance between benzene rings corresponding to the agglomeration effect of levofloxacin molecules was 0.4 nm, which should be the effect of parallel-slipped π−π electron-donor−acceptor (EDA) interactions. The simulation results are valuable to study the adsorption and removal of benzenes by adsorbent. [Display omitted] • The absorption of antibiotics by carbon nanotubes was simulated by molecular dynamics. • The agglomeration process of organic molecules was found in the process of molecular simulation. • By calculating the radial distribution between two levofloxacin molecules, it is concluded that the interaction is the parallel-slipped π−π electron-donor−acceptor interactions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Protons released from phenol electrochemical oxidation degradation form hydrogen. [•] Three stages were observed in phenol electrochemical oxidation degradation at 3V. [•] Each stages could be well described by the first order kinetic model. [•] ICE increased in first two stages while decreased dramatically in third stage. [•] Hydrogen yield improved in first stage but reduced in second stage. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic Fe3O4 particles modified sawdust (MCS) was prepared by using chitosan as the bridging reagent and characterized by FTIR analysis, and the results indicated that sawdust was successfully modified by magnetic Fe3O4 particles by connection of chitosan. The results obtained from the strontium ions adsorption experiments showed that the MCS was an effective material to remove strontium ions from aqueous solutions. And most importantly, the adsorption process was safely and easily controlled, the separation of MCS from solutions after adsorption was fast because of the magnetic modification. The adsorption of strontium ions by MCS was affected by pH, background electrolyte, adsorbent dosage and contact time. The adsorption process could achieve equilibrium in 30min, and the maximum adsorption capacity studied at different initial concentrations was 12.59mg/g. The adsorption process was a physical process which could be approved by the adsorption free energy and well fitted by the pseudo first order model. [Copyright &y& Elsevier]

Abstract: The potential of opal for removing crystal violet (CV) dye and reuse feasibility of opal-CV sludge for binding heavy metals from aqueous solutions were investigated. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and the point of zero charge (pHpzc) analysis. The thermal treatment of opal at temperatures of 300, 400, 500, 700°C increased the pHpzc value from 6.6 to 7.4 and lead to a decrease in the adsorption of CV dye, demonstrating the significance of the functional groups spread over the surface of opal. The equilibrium adsorption data fitted well to the Freundlich model and the kinetic data conformed to the pseudo-second-order model. Intra-particle diffusion was not the sole rate-controlling factor. The maximum adsorption capacity of CV was found to be 101.13mgg−1 at 30°C. The activation energy (E a) of 13.85kJmol−1 indicated that the adsorption of CV onto opal was a physisorption. Thermodynamic parameters (ΔG Θ, ΔH Θ, and ΔS Θ) were evaluated and revealed that the adsorption process was spontaneous and endothermic in nature. Moreover, the opal-CV sludge was reutilized after calcination at 250°C (O-CV-250) for the removal of heavy metals from aqueous solution. The O-CV-250 had a maximum adsorption capacity of Pb(II) of 20.92mg·g−1 while has almost no adsorption of Ni(II) and Cr(VI). Enrichment of Pb(II) was conducted and almost 65% of the Pb(II) was collected. This work presents an effective approach for the treatment of dye wastewater and reutilization of dye sludge to enrich heavy metals. [Copyright &y& Elsevier]

In this study, 26 surface seawater samples, 26 surface sediment samples and 114 organisms were collected to study the trophic transfer and dietary exposure risk of mercury (Hg) in organisms from the Jiaozhou Bay, which is a typical semi-enclosed urbanized bay. The total mercury (THg) and methylmercury (MeHg) concentrations did not exceed the threshold limits and performed as: fish > crustaceans > mollusks. The trophic level values (TLs) were less than 3 in all the groups, indicating simple structure of food chain. With the increasing δ15N value, THg and MeHg were significantly biomagnified in the mollusks and fish but not in the crustaceans. In addition, the bioaccumulation and biomagnification of MeHg were higher than inorganic mercury (IHg) in the aquatic food chain. Target hazard quotient (THQ) and provisional tolerable weekly intake (PTWI) indicated that Hg exposure via consumption of seafood from the Jiaozhou Bay did not pose significant health risks for general population. Consuming fish will face the higher health risk than crustaceans and mollusks, especially in urban regions. Moreover, the risk of MeHg caused by intaking seafood deserved more attention. Trophic transfer function (TTF) explicated the transfer of Hg in the ecosystem and higher trophic transfer efficiency of MeHg than IHg. TTF interpreted the terrestrial input of Hg should be controlled to ensure the safety of consuming seafood from the Jiaozhou Bay. [Display omitted] • Hg concentrations in aquatic samples did not exceed the threshold limit. • Hg biomagnification was observed in marine organisms in the Jiaozhou Bay. • Trophic transfer of MeHg was more obvious than IHg. • Health risk of consuming seafood was more significant in urban regions. • The terrestrial input of Hg should be controlled. [ABSTRACT FROM AUTHOR]

[Display omitted] Atrazine, a potent herbicide for weeds removal during the growing season, has been widely used in China. It is known to be distributed in aquatic ecosystems with a long half-life, thus presenting a potential risk to species and consumers. This study analyzed the concentrations of degraded atrazine residues in marine organisms (N = 129) including 3 species of mollusks, 2 species of crustaceans, and 15 species of fish from a semi-enclosed bay, Jiaozhou Bay (JZB), adjacent to the Northwest Pacific Ocean in China. The corresponding trophic magnification factors (TMF), bioaccumulation factors (BCFs), and subsequent risks to final consumers were also determined. The results showed an average atrazine concentration of (0.301 ± 0.03) ng g−1 and (0.305 ± 0.04) ng g−1 in fish and invertebrates, respectively. The BCFs were (5.23 ± 1.75) L kg−1 and (5.81 ± 1.31) L kg−1 for fish and invertebrates, respectively. Atrazine was significantly bio-diluted in JZB through the sampled marine organisms with increasing trophic levels, with a TMF value below 1 (P < 0.01). An analysis of the species sensitivity distribution (SSD) predicted that<0.02% of species were exposed to a dissolved concentration of atrazine (57.88 ng L−1) that would lead to detrimental effects, while risk quotients predicted low long-term risks for species in the bay. Finally, people with a diet limited to species from JZB were found to face no associated health risk due to a significantly small daily intake and target hazard quotient of atrazine. The corresponding non-carcinogenic effect showed no significant risk from seafood consumption. [ABSTRACT FROM AUTHOR]

Lipophilic marine algal toxins (LMATs) are highly toxic secondary metabolites produced by marine microalgae that pose a great threat to marine aquaculture organisms and human health. In this study, a novel and automated method for the simultaneous determination of six groups of LMATs in seawater was developed by on-line solid phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Condition optimization and method validation were performed, and the recoveries of all 14 target LMATs featuring different properties ranged from 83.5% to 96.0%. The limits of detection of most target compounds were within ≤3.000 ng/L with good precision (relative standard deviation ≤ 12.1%) and linearity (R 2 ≥0.9916). Compared with off-line SPE methods, the proposed on-line SPE method has better recovery, sensitivity, repeatability, and throughput; in addition, the volume of seawater sample necessary to conduct determinations is greatly reduced in the present method. Finally, the method was applied to determine LMATs in actual seawater samples collected from the Bohai and South Yellow Seas of China in summer, and okadaic acid and pectenotoxin-2 were detected in all seawater samples. The highest concentration of ∑LMATs (22.23 ng/L) occurred in the coastal mariculture area of Shandong Province. Therefore, routine monitoring of LMATs in seawater of the coastal mariculture zone is necessary to prevent shellfish contamination especially in summer, and the proposed on-line SPE-LC-MS/MS method is a powerful way for direct and automatic detection of various LMATs in coastal mariculture area. A quantitative strategy of 14 common LMATs in seawater was developed with online-SPE-UHPLC-MS/MS using MRM mode. Image 1 • A novel and automated method was developed to detect LMATs in seawater simultaneously. • On-line SPE-LC-MS/MS could achieve the rapid detection of 6 groups of typical LMATs. • A single injection requires only 2.4 mL of seawater and a total analytical time of 25 min. • The method was successfully applied to detect LMATs in the Yellow and Bohai Seas in China. • Considerable attention should be paid to the occurrence of LMATs in mariculture zone. [ABSTRACT FROM AUTHOR]

Marine algal toxins, highly toxic secondary metabolites, have significant influences on coastal ecosystem health and mariculture safety. The occurrence and environmental control factors of lipophilic marine algal toxins (LMATs) in the surface seawater of the Changjiang estuary (CJE) and the adjacent East China Sea (ECS) were investigated. Pectenotoxin-2 (PTX2), okadaic acid (OA), dinophysistoxin-1(DTX1), and gymnodimine (GYM) were detected in the CJE surface seawater in summer, with concentration ranges of not detected (ND)–105.54 ng/L, ND–13.24 ng/L, ND–5.48 ng/L, and ND–12.95 ng/L, respectively. DTX1 (ND–316.15 ng/L), OA (ND–16.13 ng/L), and PTX2 (ND–4.97 ng/L) were detected in the ECS during spring. LMATs formed a unique low-concentration band in the Changjiang diluted water (CJDW) coverage area in the typical large river estuary. PTX2, OA, and DTX1 in seawater were mainly derived from Dinophysis caudate and Dinophysis rotundata, while GYM was suspected to be from Karenia selliformis. Correlation analyses showed that LMAT levels in seawater were positively correlated with dissolved oxygen and salinity, but negatively correlated with temperature and nutrients, indicating that the hydrological condition and nutritional status of seawater and climatic factors exert significant effects on the distribution of LMATs. [ABSTRACT FROM AUTHOR]

In several watersheds, agricultural activities are the cause of pollution, mainly due to the discharge of herbicides. Often, these herbicide plumes are transported to the surrounding bays. Samples of water, suspended particulate sediments (SPSs), and sediments from 37 sites in the Jiaozhou Bay in the western Pacific Ocean were collected in April 2018. The total concentrations of atrazine and acetochlor in these samples were analyzed, that showed different patterns in each sampled area. Atrazine had 2–3 times higher concentrations in coastal areas and bays compared to the estuary, indicating that it had a higher residence time in the marine environment. In contrast, acetochlor concentration decreased with an increase in the depth of seawater. Both the spatial distributions and the vertical concentrations in water, SPS, and sediment proved that these two herbicides had different responses during transportation from the estuary to the bay. Despite the significant difference in concentration of the two herbicides in the water and sediment, their spatially averaged value in SPS was very close, indicating that the particles had saturated sorption capability. The organic carbon normalized partition coefficient (LogK oc) was used to explain the partitioning of the herbicides between water and sediment. The LogK oc difference between herbicides demonstrated that acetochlor was strongly phase partitioned in the coastal and the bay areas, thereby causing similar distributions of acetochlor in the three matrices. Atrazine had a higher LogK oc value in the estuary, which explained its higher concentration in the estuary SPS. The correlation and redundancy analyses both demonstrated that the concentrations of the herbicides in water were sensitive to dissolved organic carbon and dissolved oxygen. The current tides and bathymetry were the critical factors in determining the spatial distribution of herbicides in the water and sediment, resulting in a low herbicide load in the river mouth area. • Atrazine had higher concentrations in seawater and suspended sediment from estuary to bay. • Acetochlor has lower value in seawater and suspended sediment in the bay. • Organic carbon normalized partition coefficient proved acetochlor has strong partition process in bay. • Spatial patterns of two kinds of herbicides in the bay demonstrated their source and distribution. [ABSTRACT FROM AUTHOR]