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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]

• Four kinds of ice-making refrigeration cycles were studied with 1-D models. • 2-stage compression and ejector systems were analyzed with exergy methods. • 2-stage compression and medium-pressure ejector system is optimal in heat recovery. • 2-stage compression and low-pressure ejector system is better for ice making only. • The optimized order of components is obtained by using the exergy analysis. The transcritical CO 2 direct cooling technology was used for the first time in the indoor venues of the 2022 Beijing Winter Olympic Games. The technology has a series of advantages, such as compact structure, uniform ice temperature, energy saving and environmental protection. In order to further reduce the power consumption and improve the performance, two-stage compression and low-pressure ejector direct cooling ice making system (TCLES) and two-stage compression and intermediate-pressure ejector direct cooling ice making system (TCIES) are studied. The performance of the systems is simulated by constructing a one-dimensional thermodynamic model. The impacts of the gas cooler pressure, gas cooler outlet temperature, evaporation temperature and intermediate pressure on these systems are considered. It is showed that TCLES and TCIES have their own advantages when the system is without and with heat recovery, and found that two-stage compression improves the system performance more than the ejector when only the cooling performance is considered. On this basis, conventional exergy and advanced exergy analysis of both systems are carried out. Advanced exergy analysis shows that exergy destruction can be avoided mainly in low-pressure and high-pressure compressors of both systems. Besides, the influence of gas cooler pressure on exergy destruction characteristics is discussed. When controlling the gas cooler pressure at 9.0 MPa, the avoidable endogenous exergy destruction of compressors and ejector is reduced by a maximum of 4.14% and 13.92% for TCLES and reduced by a maximum of 16.15% and 28.04% for TCIES. [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]

BACKGROUND: The non-fusion system of lumbar interspinous process distraction device provides a new treatment option for lumbar degenerative diseases. However, at present, the clinical application and research of lumbar interspinous process distraction device are reported insufficiently in China, especially for the domestic lumbar interspinous process distraction device. OBJECTIVE: To verify the scientific nature and effectiveness of the new domestic lumbar interspinous process distraction device through finite element analysis and in vitro biomechanical experiment of goat lumbar spine. METHODS: (1) Finite element analysis of new domestic lumbar interspinous process distraction device: L2-L5 three-dimensional model of vertebral body was established based on normal adult lumbar CT data. From then on, new domestic lumbar interspinous process distraction device model, new lumbar interspinous process distraction device model of lumbar non fusion system were successively built. The mechanical conditions were given under the physiological conditions of lumbar spine. Biomechanical analysis was carried out before and after the new domestic lumbar interspinous process distraction device was implanted. (2) In vitro biomechanical analysis of new domestic lumbar interspinous process distraction device: the lumbar vertebrae (L1-L5) of 24 adult male goats were obtained, and the new domestic lumbar interspinous process distraction device was implanted between the L3-4 spinous process. Before and after the placement of the lumbar interspinous process distraction device, the lumbar motion range and the pressure of the intervertebral disc under the flexion, extension, lateral bending and rotation of the lumbar specimens were detected. RESULTS AND CONCLUSION: (1) After the new lumbar interspinous process distraction device was implanted, the motion range and the pressure of the intervertebral disc of responsible segment were reduced, while the adjacent segments' mobility and the pressure of the intervertebral disc were almost unaffected. It was theoretically verified that the new domestic lumbar interspinous process distraction device could provide the biomechanical basis for the treatment of the lumbar degenerative diseases, and contribute to the theoretical reference for the prevention of the clinical diseases. (2) In the state of extension, the motion range of L3-4 vertebral body after implanting the new lumbar interspinous process distraction device was significantly lower than that before implantation (P < 0.05). There was no significant difference between L2-3 and L4-5 vertebral body after implanting the new lumbar interspinous process distraction device and that before implantation (P > 0.05). In the state of flexion, lateral bending and rotation, there was no significant difference between L2-3, L3-4 and L4-5 vertebral body after implanting the lumbar interspinous process distraction device and that before implantation (P > 0.05). In the state of extension, the pressure of intervertebral disc after L3-4 vertebral body implantation was significantly lower than that before implantation (P < 0.05). There was no significant difference between L2-3 and L4-5 vertebral body implantation and that before implantation (P > 0.05). In the state of flexion, lateral bending and rotation, there was no significant difference between L2-3, L3-4 and L4-5 vertebral body implantation and that before implantation (P > 0.05). (3) The results showed that the scientific nature and validity of the new domestic lumbar interspinous process distraction device was verified by three-dimensional finite element analysis and in vitro animal lumbar specimens experiment, which provided a strong basis for the animal experiment, clinical experiment, clinical application and clinical production of the new domestic lumbar interspinous process distraction device. [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]

Abstract Blue holes can provide valuable information regarding paleoclimate, climate change, karst processes, marine ecology, and carbonate geochemistry. The Sansha Yongle Blue Hole, located on Yongle Atoll in the Paracel Islands in the South China Sea, is the deepest blue hole in the world. A comprehensive investigation of the blue hole was conducted to determine the hydrochemical properties and associated redox processes active in the water column. Results indicate the presence of two thermoclines, one at 13–20 m and a second at 70–150 m, dividing the water column into five stratified water layers. Based on redox state, the water column can be divided into three layers: an oxic layer in the top 70 m, a chemocline at 70–100 m, which acts as a redox boundary, and an anoxic deep layer. In the oxic layer, photosynthesis in the oxic layer above the seasonal thermocline, results in nutrient uptake, transformation of inorganic carbon to organic carbon in the top mixed layer above the seasonal thermocline; Below the seasonal thermocline, organic matter degradation and nitrification, which are the main biological process at depths around 30 m and 50–70 m, lead to the accumulation of nitrate and a decrease in dissolved oxygen and pH; whereas photosynthesis is dominant at depths of 30–50 m, leading to increase in dissolved oxygen and pH. Within the chemocline, organic matter decays via a variety of reactions (e.g. aerobic mineralization, denitrification and anammox), leading to sharp decreases in the oxidizing chemical species (e.g., dissolved oxygen and nitrate) and corresponding increases in the reduced species (e.g., ammonium and sulfide). Within this layer, about 60% of the nitrogen is lost and chemoautotrophic/photoautotrophic production may contribute significantly to particulate organic carbon. Within the deep anoxic layer, sulfate reduction and degradation of organic matter result in accumulations of sulfide, dissolved inorganic carbon, and nutrients. Graphical abstract Unlabelled Image Highlights • Distinct water layers involve different redox/nitrification-denitrification process. • A 30-m thick chemocline separates the upper oxic layer and the deep anoxic layer. • The blue hole is a net source of N 2 O and CH 4 to the atmosphere. [ABSTRACT FROM AUTHOR]

Graphical abstract Breakthrough curves of acetaldehyde and acetone in binary system. Highlights • Adsorption isotherms of acetaldehyde/acetone onto coconut shell activated carbon were obtained in single and binary systems. • Henry's law constant and the selectivity were investigated to understand adsorbent and adsorbate affinity. • Integral free energy functions were useful parameters to understand adsorption behavior. • Adsorbed acetaldehyde was displaced by acetone in co-adsorption system. Abstract The adsorption characteristics of acetaldehyde/acetone onto coconut shell activated carbon (CSAC) were investigated with a dynamic apparatus. The Langmuir, Freundlich and Sips models were used to analyze the adsorption isotherm data in single gas system, revealing that the Freundlich model most suitably described the adsorption of the two gases. Henry's law constant and the selectivity were investigated based on adsorption isotherms to understand adsorbent and adsorbate affinity. A thermodynamic study also revealed that the adsorptions were exothermic and phyiscal. The adsorption of these studied gases is likely to be heterogeneous. Acetone formed the more ordered configuration on CSAC, but molecular acetaldehyde has higher degree of freedom. For the binary adsorption system, the equilibrium data fit well with the Extended Freundlich model. The competitive adsorption experiment indicated that acetone was more selectively adsorbed than acetaldehyde on CSAC. In particular, because of the displacement of adsorbed acetaldehyde by acetone the acetaldehyde demonstrated a maximum excess concentration. [ABSTRACT FROM AUTHOR]

SBA-15 mesoporous materials loaded with 8%–42% TiO 2 were prepared by post-synthesis hydrolysis using ilmenite as the TiO 2 source. X-ray diffraction, high-resolution transmission electron microscopy, nitrogen adsorption–desorption measurements, and Fourier-transform infrared, X-ray photoelectron, Raman, and ultraviolet-visible spectroscopies were used to investigate the TiO 2 /SBA-15 morphology and crystal structure. The results show that TiO 2 was successfully loaded on the mesoporous SBA-15 and the highly ordered two-dimensional hexagonal structure was stable. The photocatalytic performances of the samples in dimethoate degradation under simulated solar light were investigated. The photocatalytic activity initially increased and then decreased with increasing TiO 2 loading. The 26% TiO 2 /SBA-15 sample showed the highest photocatalytic activity and completely degraded dimethoate within 7 h. The catalytic activity of TiO 2 /SBA-15 was 62% higher than that of pure TiO 2 . This may be because of a synergistic effect resulting from the adsorption of dimethoate on the mesoporous material. The presence of Ti–O–Si species enhances the TiO 2 surface acidity and formation of surface adsorption sites; The adsorption and electron delocalization properties of SBA-15 are the main reasons for the observed enhancement of the pesticide degradation rate. These improves the TiO 2 /SBA-15 photocatalytic activity. TiO 2 /SBA-15 maintained high photocatalytic activity and good stability during four cycles, with a dimethoate degradation rate greater than 94%. The byproducts generated during photocatalysis were identified using gas chromatography-mass spectrometry. The photocatalytic degradation of dimethoate followed first-order kinetics. The mechanism of the photocatalytic degradation of dimethoate was investigated. [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]

Using an alkali two-step hydrothermal method, SBA-15 mesoporous molecular sieves were prepared from fly ash used in a thermal power plant in Inner Mongolia (China). The effect of alkali solution (i.e., NaOH), added in different amounts at 95 °C, on the desilication rate of the ash was determined. During the 48-h hydrothermal crystallization process at 110 °C, sieves were obtained using Na 2 SiO 3 solution as the silicon source, hydrochloric acid to adjust the pH value, and P123 (PEO-PPO-PEO) as a template. Amino-functionalized molecular sieves were prepared at 120 °C, using 3-aminopropyltriethoxysilane as a modifier and toluene as the solvent. The prepared SBA-15 and NH 2 -SBA-15 molecular sieves were characterized via X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and N 2 adsorption. The effects of adsorption time, temperature, pH value, and the initial concentration of lead ions (Pb 2+ ) on the efficiency of Pb 2+ removal were investigated using NH 2 -SBA-15 as an adsorbent. The results revealed that, like its SBA-15 counterpart, NH 2 -SBA-15 has a typical two-dimensional hexagonal pore structure, with lower specific surface area, average pore diameter, and pore volume compared with its SBA-15 counterpart. Furthermore, the Pb 2+ -removal efficiency increased gradually with increasing adsorption time, adsorption temperature, and initial concentration of Pb 2+ . However, when the pH value was increased, the efficiency increased initially and decreased thereafter. The maximum removal rate (>98%) after 60 min at 30 °C was obtained at a pH value of 5 and a Pb 2+ concentration of 100 mg/L. The adsorption process of Pb 2+ and the corresponding adsorption isotherm were well described by the second-order kinetics model and the Langmuir isotherm model, respectively, and an equilibrium adsorption amount of 131 mg/g was realized. The fly-ash-based SBA-15 mesoporous molecular sieve adsorbent, developed and subsequently modified in the present study, exhibited improved selectivity and adsorption capacity, and was less expensive than existing adsorbents. This sieve can provide effective technical support for control of the industrial heavy-metal-contaminated wastewater, and provides a new approach for the efficient utilization of fly ash. [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]

Based on literature data and shipboard observations, this study investigated the main environmental characteristics of the seafloor topography, current field, front, and upwelling that are closely related to hypoxia occurrence off the Changjiang estuary. The physical processes of the plume front and upwelling off the Changjiang estuary in summer were coupled. The vertical distribution pattern of the plume front was closely related to the upwelling. By reviewing and analyzing the historical summer hypoxia events off the Changjiang estuary, we statistically demonstrated the spatial structure of the horizontal distribution of the hypoxic zone and investigated the location of occurrence zone of the hypoxia. We found that the dissolved oxygen (DO) concentration on the inner continental shelf off the estuary showed a 'V' shape in relation to station depth. Therefore, we noted that the hypoxic water on the inner continental shelf mostly occurred on the slopes with steep seafloor topography. Base on the current understanding of the hypoxic mechanisms off the Changjiang estuary, we analyzed the biogeochemical mechanisms that could cause the steep terrain off the Changjiang estuary to become the main areas prone to summer hypoxia and explained the internal relations between the location of the hypoxic zone on the slopes and the plume front and upwelling. The plume front and upwelling off the Changjiang estuary and their coupling were important driving forces of summer hypoxia. The continuous supply of nutrients affected by the interaction of the plume front extension of the Changjiang Diluted Water (CDW) and upwelling and the favorable light conditions were important mechanisms causing the phytoplankton blooms and benthic hypoxia off the Changjiang estuary in summer. By analyzing oxygen utilization, organic carbon mineralization, and nutrient regeneration in the hypoxic zone, we observed that the significant oxygen utilization process off the Changjiang estuary in summer also mainly occurred near the steep slopes with front and upwelling features and confirmed the apparent nutrient loss in the benthic hypoxic zone. Meanwhile, our analysis revealed that the sediment resuspension in the benthic boundary layer in the mud areas off the Changjiang estuary could also affect the oxygen utilization and mineralization of organic carbon and nutrient recycling and regeneration. This study also demonstrated that the steep terrain off the Changjiang estuary was the main location for summer acidification, and the coupling between the plume front and upwelling on the steep slopes was an important physical driving force inducing summer benthic acidification. Finally, we discussed issues to address in future studies of the hypoxic zone and water acidification off the Changjiang estuary. [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]

On the basis of compiled multidisciplinary historical data in 2006-2007 and incorporation of relevant simulation results and remote sensing data, we performed an in-depth study of the generation and dissipation process of the hypoxic zone and its distribution morphology and structure off the Yangtze River estuary. Based on the hydrological circulation dynamics, reproduction of phytoplankton (leading to the decomposition of organic matter), and other factors, we comprehensively and systematically investigated the generation and dissipation of the hypoxic zone and underlying mechanisms for the seasonal variation in its position, explored the multi-factorial synergistic reactions during the generation and dissipation process of the hypoxic zone, and revealed the controlled mechanism for the morphology and structure of the hypoxic zone's distribution. Our studies indicate that in the winter and spring seasons, the hydrological environment off the Yangtze River estuary provides a water body with relatively low contents of dissolved oxygen (DO), which is the background for the formation of a hypoxic zone. After entering into the summer season, the hypoxic zone gradually develops towards the north and becomes mature. Because of the impact of the terrain, local decomposition of organic matter, and upwelling of the Kuroshio subsurface water in July-August, the hypoxic zone off the Yangtze River estuary exhibits the characteristics of discontinuous distribution in space and has a south and north 'dual-core' structure in the inner continental shelf. In addition, there is a hypoxic core in the eastern outer continental shelf. The degrees of hypoxia vary for different areas; they are strongest overall in the north, next strongest in the south; they are weakest on the outer continental shelf. In summer, the hypoxic zone in the north is related to the northward differentiation of the southern hypoxic zone and results from local development and intensification. In August, the hypoxic zone in the north reaches its peak, and after September, it rapidly retreats southward and disappears because of weakening stratification. In the fall, there is hypoxic zone along the coast of Zhejiang in the south, and there is also a low-DO area to the southwest of Jeju Island, with both zones disappearing rapidly. In addition, the change of dynamic environment also causes the low-DO area of the outer continental shelf to move outward in the fall. The variation in the intensity of the stratification and its cumulative effects as a barrier of vertical DO transportation over long periods of time have a significant impact on the degree of hypoxia in the hypoxic zone. In addition, the seasonal variations in the size of the stratified region, intensity of each current system/water mass, upwelling, front, and high-value area of phytoplankton biomass jointly restrict the extension of the hypoxic zone in the inner continental shelf and latitudinal (south-north direction) movement of its location off the Yangtze River estuary. The combined effect of dynamic factors, such as that of the Kuroshio subsurface water, causes a low-DO core in the outer continental shelf. The bottom cold water to the north of the East China Sea is the dynamic basis for the formation of the low-DO area to the southwest of Jeju Island during the fall season. The special seabed topography and mud area distribution off the Yangtze River estuary have a certain degree of influence on the development of the hypoxic zone. The generation and dissipation of the hypoxic zone and its distribution morphology off the Yangtze River estuary, and seasonal variation of its structure and position are a result of the synergistic effects of various factors. [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: The annual cycle of hypoxia off the Changjiang Estuary, China, was assessed from data acquired during nine cruises in 2006–2007. Hypoxia began to develop in late spring and early summer, reached its maximum in August, weakened in the autumn and finally disappeared in the winter. Hypoxia first developed south-east of the Changjiang Estuary in June, appeared in the east and north-east in July, and spread both south and north of the Changjiang Estuary in August. By September, it had started to recede in the north-east, and had dissipated in the southern part of the studied area by winter. The geographical displacement of the hypoxic zone was controlled by both seasonal changes in regional water column stratification and variations of the northward extension of the Taiwan Warm Current toward the Changjiang Estuary. [Copyright &y& Elsevier]

Based on the seasonal surveying data and long-term data, the annual changes in the geographical locations, occurrence frequency, affected areas and the minimum oxygen level as well as the formation mechanism of the summer hypoxia off the Changjiang estuary are summarized and discussed in this paper. The historical data indicates that there were episodes of hypoxia in the past 50 years but not every year, and the event of summer hypoxia could be traced back to as early as late 1950s off the Changjiang estuary. The minimum oxygen levels in the hypoxia zone did not show any decline in the past 50 years, but all the events with large size of affected area (>5000km2) were observed after the late 1990s, suggesting an enlarging trend. The author argues that the development of summer hypoxia off the Changjiang estuary was related not only to stratification and input of suspended particulate matter, but also to the inflow of Taiwan warm current water as well as the bottom topography. [Copyright &y& Elsevier]

Reinforced thermoplastic pipes (RTP) are widely used in the offshore oil and gas production industry for their excellent flexibility, corrosion resistance and internal pressure resistance. RTPs inevitably experience extreme environmental loads including internal pressure and tensile load in the procedures of installation and operation, which influence the structural integrity and safety. Therefore, reinforced layers of RTP are designed to bear internal pressure and tensile load. Herein, the mechanical behavior of fiber-reinforced thermoplastic pipe that consisting of aramid fiber braid reinforced layers is investigated by combination of numerical simulation and experimental methods. The full-scale internal pressure bursting experiments of 1-inch aramid fiber RTPs were carried out to study the burst pressure and failure behavior. A finite element model of aramid fiber RTP is established using ABAQUS, which considers the material nonlinearities as well as frictional interactions between layers. Based on the finite element model which validated by the experimental results, the mechanical behavior of fiber reinforced thermoplastic pipe subjected to internal pressure and tensile load is investigated in detail. The current study compares the influence of braided angle of fiber-reinforced layers, friction coefficient between each layer and load conditions on the mechanical behavior of RTPs. The experiment results reveal that the bursting pressure of 1-inch aramid fiber RTPs is about 76.1 MPa. The failure of aramid fiber RTP under internal pressure is dictated by leakage due to the fracture of fiber-reinforced layers and the fracture of the internal layer at the end fitting. It is worth noting that the braiding angle renders an obvious influence on mechanical properties of fiber-reinforced RTPs, whereas the mechanical behavior remains insensitive to friction coefficient between layers. Moreover, the synergistic influence of internal pressure and tensile load significantly affects the mechanical behavior of fiber-reinforced RTPs. The current study shall serve as a reference for the design and application of fiber-reinforced thermoplastic pipes in marine oil and gas production. • The full-scale internal pressure bursting experiments of 1-inch aramid fiber RTP were carried out to investigate the failure behavior of the RTP, and the failure model and ultimate load of aramid fiber reinforced thermoplastic flexible pipe under internal pressure were clarified. • A finite element model of aramid fiber RTP is established, which considers geometrical and material nonlinearities as well as frictional interactions between layers. • The influence of braided angle of fiber-reinforced layers, load conditions and friction coefficient between each layer on the mechanical behavior of RTPs were studied in detail. [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]

Abstract: The Changjiang (Yangtze River) is known to contribute significantly to the eutrophication that has caused drastic changes to the ecosystem of the East China Sea. However, evidence for historical changes in nutrient concentrations and composition and the consequent effects on the ecosystem in the coastal water is sparse. In this paper we present some long-term data for nutrient concentrations and Si:N:P ratios in the freshwater and the river plume and the long-term response of the ecosystem structure in the river plume. These data reveal increases in the dissolved inorganic nitrogen and phosphate concentrations in the Changjiang freshwater by a factor of five from the1960s to the end of the 1990s and a reduction in dissolved silicate by two thirds over the same period. Concomitantly, an increase in DIN concentration and a reduction in silicate concentration both by a factor of two were observed in the surface water of the Changjiang plume. As an ecological consequence to such nutrient changes, the chlorophyll a concentration increased by a factor of four since the 1980s and harmful algal blooms increased rapidly since 1985 in the Changjiang estuary and adjacent sea areas. The macrozoobenthic biomass decreased sharply from the mid 1980s to the present, suggesting that the Changjiang estuary has been in a high eutrophication state since that time. We predict that, due to the continuously increasing nutrient pressure, the symptoms of eutrophication associated with nutrients will worsen in the Changjiang plume in the near future. [Copyright &y& Elsevier]

The Changjiang (Yangtze River) Diluted Water (CDW) plume substantially impacts the biogeochemical processes off the estuary and its adjacent area, resulting in considerable environmental and ecological effects. Based on survey data in the northeastern area off the Changjiang Estuary (CE) obtained in the summers of 2008 and 2013, the hypoxia induced by the offshore detached CDW plume and the associated controlling mechanisms were investigated. The results show that the offshore transport of the CDW plume caused a dispersed low-salinity area in the northeastern area off the CE during summer, in sharp contrast with the surrounding high-salinity and high-density waters. There was a hypoxic area with low-pH (i.e., acidification) near the 40-m isobath in bottom waters in the northeastern area off the CE, and its position generally corresponded to the surface offshore CDW plume. In the area affected by the offshore low-salinity water, the surface patch-like phytoplankton bloom and the organic debris produced in situ were the material drivers of the bottom oxygen consumption and led to the corresponding relationship between the bottom hypoxic zone and the high chlorophyll-a (Chl-a) area at the surface. We consider that the local stratification caused by the offshore low-salinity water and the stable environment within the detached CDW plume constituted the external dynamic conditions for maintaining the bottom hypoxia. Our results demonstrate that the offshore detached CDW plume in the northeastern area off the CE may contribute to the formation of a local hypoxic center with low pH. This study would provide basis for understanding of the physical-biogeochemical processes and environmental responses in the offshore areas of the CDW plume. Unlabelled Image • Co-occurrence of offshore diluted water plume and hypoxia was observed in the northeastern area off the Changjiang Estuary • The surface patchness of phytoplankton bloom corresponded to the bottom hypoxic zone • Offshore detachment of the Changjiang Diluted Water can contribute to the formation of hypoxia and acidification [ABSTRACT FROM AUTHOR]

The ubiquitous and adverse effects of estrogens have aroused global concerns. Natural and synthetic estrogens in 255 water samples from the southern Bohai Sea were analyzed over three years. Total estrogen concentrations were 11.0–268 ng/L in river water and 1.98–99.7 ng/L in seawater, with bisphenol A (BPA) and 17α-ethynylestradiol (EE2) being the predominant estrogens, respectively. Estrogen showed the highest concentrations in summer 2018, followed by spring 2021 and spring 2019, which was consistent with the higher estrogen flux from rivers during summer. Higher estrogen concentrations in 2021 than in 2019 were driven by the higher level of BPA, an additive used in personal protective equipment. Estrogen exhibited higher concentrations in the southern coast of the Yellow River Delta and the northeastern coast of Laizhou bay due to the riverine input and aquaculture. Estrogens could disturb the normal endocrine activities of organisms and edict high ecological risks (90th simulated RQ T > 1.0) to aquatic organisms, especially to fish. EE2 was the main contributor of estrogenic potency and ecological risk, which requires special concern. This is the first comprehensive study of estrogen spatiotemporal variations and risks in the Bohai Sea, providing insights into the environmental behavior of estrogens in coastal regions. [Display omitted] • BPA and EE2 were dominant in river water and seawater, respectively. • Riverine input & mariculture lead to higher estrogen levels in summer than spring. • Spatial distribution of estrogens was influenced by mariculture and riverine input. • Estrogens caused high risks to aquatic organisms, particularly to fish. • EE2 was the main contributor of estrogenic potency and ecological risk. [ABSTRACT FROM AUTHOR]

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]

A series of vanadium based catalysts (V x Mn(4− x)Mo3Ce3/Ti) with different vanadium (x wt.%) and manganese ((4− x) wt.%) contents have been prepared by the wet impregnation method and investigated for selective catalytic reduction (SCR) of NO x by NH 3 in the presence of 8 vol.% H 2 O and 500 ppmV SO 2. The physicochemical characteristics of the catalysts were thoroughly characterized. The SCR of NO x by NH 3 (NH 3 -SCR) activity, especially the low-temperature activity, significantly increased with increasing V 2 O 5 content in the catalyst until the V 2 O 5 content reached 1.5 wt.%, which corresponds well with the redox properties of the catalyst. All of the metal oxides were well dispersed and strongly interacted with each other on the catalyst surface. V mainly exists in the V5+ state in the catalysts. The strong synergistic effect between the vanadium and cerium species led to formation of more Ce3+ species, and that between the vanadium and manganese species contributed to formation of more manganese species with low valences. All of the catalysts exhibited strong acidity, while the redox properties determined the NH 3 -SCR activity, especially the low-temperature activity. H 2 O and SO 2 had severe inhibiting effects on the activity of V1.5Mn2.5Mo3Ce3/Ti. However, good H 2 O and SO 2 resistance and high NO x conversion by V1.5Mn2.5Mo3Ce3/Ti could be achieved in the presence of SO 2 and almost no decline was observed in a long-term test at 275°C for 168 hr in the presence of SO 2 and H 2 O, which can be attributed to the sulfate species formed on the catalyst surface. Unlabelled Image [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 impacts of the COVID-19 pandemic on the occurrence of OPEs were investigated. • Total OPE concentrations decreased by 67–70% in waters after the COVID-19 outbreak. • OPEs released from masks were insufficient to increase their concentrations in water. • Spatial distribution of OPEs was affected by riverine inputs & coastal engineering. • TCEP, TNBP, and BDP showed potential ecological risks to aquatic organisms. Organophosphate esters (OPEs) are a group of synthetic chemicals used in numerous consumer products such as plastics and furniture. The Coronavirus Disease 2019 (COVID-19) pandemic significantly slowed anthropogenic activities and reduced the emissions of pollutants. Meanwhile, the mismanagement of large quantities of disposable plastic facemasks intensified the problems of plastic pollution and leachable pollutants in coastal waters. In this study, the joint effects of the COVID-19 outbreak on the occurrence of 12 targeted OPEs in the waters of Laizhou Bay (LZB) were investigated. The results showed that the median total OPE concentrations were 725, 363, and 109 ng L−1 in the sewage treatment plant effluent, river water, and bay water in 2021, decreased significantly (p < 0.05) by 67%, 68%, and 70%, respectively, compared with those before the COVID-19 outbreak. The release potential of targeted OPEs from disposable surgical masks in the LZB area was ∼0.24 kg yr−1, which was insufficient to increase the OPE concentration in the LZB waters. The concentrations of most individual OPEs significantly decreased in LZB waters from 2019 to 2021, except for TBOEP and TNBP. Spatially, a lower concentration of OPEs was found in the Yellow River estuary area in 2021 compared with that before the COVID-19 pandemic due to the high content of suspended particulate matter in the YR. A higher total OPE concentration was observed along the northeastern coast of LZB, mainly owing to the construction of an artificial island since 2020. The ecological risks of the OPE mixture in LZB waters were lower than those before the COVID-19 outbreak. However, TCEP, TNBP, and BDP should receive continuous attention because of their potential ecological risks to aquatic organisms. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to propose an online local trajectory planner for safe and fast trajectory generation that combines the jerk-limited trajectory (JLT) generation algorithm and the particle swarm optimization (PSO) algorithm. A trajectory switching algorithm is proposed to improve the trajectory tracking performance. The proposed system generates smooth and safe flight trajectories online for quadrotors. Design/methodology/approach: First, the PSO algorithm method can obtain the optimal set of target points near the path points obtained by the global path searching. The JLT generation algorithm generates multiple trajectories from the current position to the target points that conform to the kinetic constraints. Then, the generated multiple trajectories are evaluated to pick the obstacle-free trajectory with the least cost. A trajectory switching strategy is proposed to switch the unmanned aerial vehicle (UAV) to a new trajectory before the UAV reaches the last hovering state of the current trajectory, so that the UAV can fly smoothly and quickly. Findings: The feasibility of the designed system is validated through online flight experiments in indoor environments with obstacles. Practical implications: The proposed trajectory planning system is integrated into a quadrotor platform. It is easily implementable onboard and computationally efficient. Originality/value: The proposed local planner for trajectory generation and evaluation combines PSO and JLT generation algorithms. The proposed method can provide a collision-free and continuous trajectory, significantly reducing the required computing resources. The PSO algorithm locally searches for feasible target points near the global waypoint obtained by the global path search. The JLT generation algorithm generates trajectories from the current state toward each point contained by the target point set. The proposed trajectory switching strategy can avoid unnecessary hovering states in flight and ensure a continuous and safe flight trajectory. It is especially suitable for micro quadrotors with a small payload and limited onboard computing power. [ABSTRACT FROM AUTHOR]

• PPCPs decreased gradually in detection rates and levels from rivers to coastal seas. • Amoxicillin and p-hydroxybenzoic acid accounted for over 50% of the total PPCPs. • Southeastern waters outside the yangtze estuary had higher PPCP concentrations. • PPCP mixtures posed medium to high risks to different aquatic organisms. • Priority PPCPs with high ecological risks were identified. Pharmaceuticals and personal care products (PPCPs) have captured global concern due to their detrimental effects on aquatic organisms. Thirty PPCPs were analyzed in the water of the Jiaozhou Bay watershed, the Yellow Sea (YS) and the East China Sea (ECS) in China to investigate the distribution and risk of PPCPs from rivers to coastal seas, which are not yet well documented. The results showed the prevalence of the target PPCPs with a downward trend in detection frequencies and total concentrations from rivers (675 ng/L on average) to bay (166 ng/L) and to coastal seas (103 ng/L). Antibiotics and personal care products (PCPs) were dominated by amoxicillin (AMOX) and p-hydroxybenzoic acid, respectively, while the dominant estrogens were inconsistent in different regions. Spatially, the total PPCP concentrations were higher in the ECS than that in the YS due to the larger quantity of sewage flowing into the ECS. Additionally, higher total PPCP concentrations were appeared in the southeastern waters outside the Yangtze estuary and Hangzhou Bay of the ECS. The PPCP mixtures might pose medium to high risk to aquatic organisms in general. The total risk quotient (RQ T) of antibiotics and PCPs to algae was higher than that to crustacean and fish, while estrogens may cause the greatest damage to fish. Despite the higher PPCP concentrations in river water than in seawater, the RQ T of PPCPs in bay water was generally higher than that in river water, which may be associated with the susceptibility of marine organisms. Furthermore, the high-risk pollutants that need special concern in different regions were clarified, showing that AMOX, 17ß-estradiol, and estriol deserve the highest-priority in rivers, bay, and coastal waters, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

Lipophilic marine algal toxins (LMATs) are produced by some toxigenic microalgae, which pose a serious threat to marine ecosystem and even human health. The occurrence and environmental control factors of LMATs in the surface seawater and phytoplankton in spring in Laizhou Bay in which Huanghe (Yellow) River estuary is included, in Shandong, East China were investigated. Okadaic acid (OA), pectenotoxin-2 (PTX2), dinophysistoxin-1 (DTX1), pectenotoxin-2 seco acid (PTX2 SA), DTX2, 7-epi-PTX2 SA, PTX11, and 13-desmethyl spirolide C (SPX1) were detected from the surface seawater samples, and PTX2, 7-epi-PTX2 SA, OA, DTX2, DTX1, PTX2 SA, and PTX11 were discovered in the phytoplankton samples showed a decreasing trend. The concentrations of ∑LMATs in the seawater and phytoplankton ranged 2.03–74.38 ng/L on average of 13.72 ng/L and 0.98–479.27 pg/L on average of 50.20 pg/L, respectively. The joint influence of terrigenous input and internal circulation could promote the growth, toxin production, and toxin release of toxin-producing algae, leading to a higher content of LMATs in the bay nearby the Huanghe River estuary in both seawater and phytoplankton. The concentration of LMATs in spring was higher than that in summer, showing obvious seasonal variation. In addition, no significant correlation between most of the physiochemical parameters and LMAT contents in seawater was revealed by correlation analysis except for the positive correlation between DTX2 and chlorophyll a, OA and NH4-N. However, the increase of dissolved inorganic nitrogen content in seawater could enhance the production of OA, DTX1, and DTX2 in phytoplankton due probably to that the inorganic N input could benefit the growth and stimulate toxin production of toxin-producing algae. The result also proved that some PTX2 may be originated from Procentrum spp. and OA, DTXs and part of PTX2 may be originated from Dinophysis spp. [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]

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]

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]

Nutrients play a major role in sustaining marine ecosystems. However, in the past few decades, nutrient inputs from land have significantly changed worldwide, resulting in the variations in nutrient concentrations and compositions in marginal seas. Based on historical data, the long-term variation patterns of nutrients and its compositions, as well as its potential influencing factors, were presented in the southern Yellow Sea. The concentrations of NO 3 -N and dissolved inorganic nitrogen (DIN) in the southern Yellow Sea have been continuously increasing from the 1980s, with a most rapid increase after the mid-1990s. While the concentrations of SiO 3 -Si and PO 4 -P generally exhibited a decreasing trend before the mid-1990s, and then gradually increased. The N/P ratio has been continuously increasing from the 1980s and run up to a level of >16 at the end of the last century. The Si/N ratio decreased rapidly from the mid-1980s to the mid-1990s and then maintained a low level of ~1 at the end of the last century and at the beginning of this century. Similar to the variation of SiO 3 -Si, the Si/P ratio decreased from the 1970s to the mid-1990s and then started to increase gradually. There was an evolution trend from N limitation to P and Si limitation in the southern Yellow Sea. The variations in the concentrations of nutrients were related to the variations of the riverine flux and atmospheric deposition, and especially the long-term variations of PO 4 -P and SiO 3 -Si concentrations were both consistent with the variation of precipitation. In addition, the nutrient transport from the Kuroshio Subsurface Water to the continental shelf, in combination with the cultural eutrophication in the coastal zones, may also influence the nutrient levels in the southern Yellow Sea under the global change. [ABSTRACT FROM AUTHOR]

• Yellow River PAH input & sea currents determined PAH spatial distribution in the sea. • Yellow River alluvial loess solid dilution effect led to lower PAH levels in the sediment. • Yellow River & Yellow Sea water dilution effect led to lower PAH levels in the water. • PAH properties decided its partitions in surface/bottom water & bottom water/sediment. • PAH ecological risks in both water and sediment were negligible or acceptable. The marginal Bohai Sea, connected to the northwestern Pacific Ocean, is threatened by human activity. The Yellow River, the second largest river in China, drains large amounts of water, silts, and polycyclic aromatic hydrocarbons (PAHs) into the southern Bohai Sea; however, to what extent the Yellow River inputs influence the spatial distributions and partitions of PAHs in the southern Bohai Sea is not well known. Therefore, this study collected surface water, bottom water, and sediment samples from the southern Bohai Sea and analyzed them to examine the spatial distributions and partitions of 15 priority PAHs. The results showed that PAH concentrations ranged from 26.9 to 50.1 ng L–1 in surface water, 18.8 to 44.1 ng L–1 in bottom water, and 7.4 to 143.9 ng g–1 in sediment, with higher proportions of four-, five-, and six-ring PAHs in sediment than in water. PAH inputs from the Yellow River and sea coastal currents determined the spatial distribution of PAH concentrations in water and sediment, with an overall decrease from the estuary to the southeast. However, the solid dilution effect of input silts from the Yellow River and the liquid dilution effect of water from the Yellow River and Yellow Sea led to lower PAH concentrations in the water and sediment of the southern Bohai Sea than those in other areas of the Bohai Sea. PAH exchange between the atmosphere and seawater led to significantly higher individual PAH concentrations (except for acenaphthylene) in the surface water than in the bottom water, with ratios significantly related to the PAH n-octanol-water partition coefficient, organic carbon-water partition coefficient, and Henry's law constants. These parameters also determined PAH partitioning between the bottom water and sediment. Individual and total PAH concentrations in the sediment were significantly correlated with organic matter, clay, and silt contents. Therefore, the partitions and spatial distributions of PAHs in the southern Bohai Sea comprehensively depend on PAH properties, PAH inputs from the Yellow River and the atmosphere, sea currents, and seawater and sediment properties. The ecological risks posed by individual PAHs in both water and sediment were negligible or acceptable. [Display omitted] [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]

Coastal contamination by polycyclic aromatic hydrocarbons (PAHs) is a worldwide issue. Nevertheless, the spatiotemporal distribution of PAHs in the urbanized semi-enclosed bays in China remains relatively uncharacterized. Here we present measurements of 15 priority PAHs in the water and sediment of the Jiaozhou Bay, as well the assessment of their spatiotemporal distribution, sources and ecological risk. The total PAH (ΣPAH) concentrations ranged from 23.6 to 86.2 ng L −1 in the water and from 37.7 to 290.9 ng g−1 in the sediment. The average ΣPAH concentration in the water was significantly higher in the winter (52.8 ng L −1) than in the spring (30.4 ng L −1) (α = 0.05 level). Average concentration of phenanthrene in the water was 8.9 ng L−1 in the spring and 15.7 ng L−1 in the winter and the highest of PAHs, contributing about 29.4% to ΣPAHs. Compared with three-ring PAHs, four- and five-ring PAHs were more tended to accumulate in the sediment, and the partitioning into sediment was influenced by the water salinity. The spatial distribution of ΣPAH concentrations in the water were controlled by water exchange capability. Organic matter content and sediment texture played important roles in determining the spatial distribution of ΣPAHs in the sediment. Molecular diagnostic ratio analysis indicated that pyrogenic source was the main source for PAHs in the Bay. Specifically, the positive matrix factorization (PMF) model indicated that vehicle emission, biomass combustion, coal combustion, and petrogenic sources contributed for 41.6, 20.2, 20, and 18.2% of ΣPAHs, respectively. The risk assessment by sediment quality guidelines suggested that adverse biological effects are expected to occur rarely in the sediment. Unlabelled Image • ΣPAH concentration in water was significantly higher in winter than in spring. • Water salinity may play a role in PAH partitioning into sediment. • Water exchange capability controlled spatial PAH distribution in water. • Organic matter and texture may influence spatial PAH distribution in sediment. [ABSTRACT FROM AUTHOR]

The Jiaozhou Bay is a semi-enclosed bay located in the middle of the Yellow Sea. Effluents from wastewater treatment plants have been carried into the bay, which has significantly increased the deposition of mercury. The spatial distributions of total mercury (THg) and methylmercury (MeHg) in dissolved state, in suspended matters of seawater and surface sediments at 26 locations inside the Jiaozhou Bay and five surrounding rivers in April 2018 were examined. The contents of THg and MeHg found along the eastern coast were higher than those found along the western coast, which indicated the impact of human activities (river input) on the Jiaozhou Bay. The partition coefficient (LogKd) was used to express the distribution relationships of THg and MeHg in suspended matters and dissolved state, and it was concluded that suspended matter was the main reservoir of mercury in Jiaozhou Bay seawater. The correlations between contents and physicochemical properties of seawater showed that THg and MeHg concentrations in seawater decreased with increasing salinity and pH. The effects of the mean grain diameter (MGD) and sediment organic matter (SOM) on the THg and MeHg in surface sediments were also discussed. Principal component analysis (PCA) was used to obtain the factors determining the methylation proportion in the surface sediments, indicating that the combination of human activities and natural processes affected the degree of methylation in the sediments. The spatial distribution of THg, MeHg and MeHg% was suggested to be disturbed by the interaction of natural processes and human activities (river input) by the correlation analysis of the corresponding pollutant concentrations among seawater and. Although the concentrations of THg and MeHg in seawater and sediments of the Jiaozhou Bay did not exceed the Chinese regulatory standards, the pollution levels of THg and MeHg were comparable to those in other bays in the world. Unlabelled Image • Suspended matter was the main reservoir of mercury in seawater. • The distribution patterns of THg and MeHg indicated the impact of human activities. • Key factors affecting the level of Hg by correlation were salinity, pH, SOM and MGD. • Pollution by THg and MeHg was not serious in the Jiaozhou Bay. [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]