This paper presents the free vibration analysis of combined composite laminated conical–cylindrical shells with varying thickness using the Haar wavelet method (HWM). The displacement field of the ...combined shell is set based on the first-order shear deformation theory (FSDT), the displacement components, and rotation of individual shells including boundary conditions that are expanded by the Haar wavelet and Fourier series in the meridional and the circumferential direction. By solving the vibration characteristic equation discretized by the Haar wavelet, the vibrational results of combined shells are obtained. Then, the results of the proposed method are compared with those of published literature and finite element analysis (FEA). The results show that HWM has high convergence and high accuracy for the free vibration analysis of the combined composite laminated conical–cylindrical shells with varying thickness. Also, the effects of the parameters such as thickness variation parameters, material properties, geometrical dimensions, and different boundary conditions, on the vibrational behavior of the combined shells are investigated. Finally, new numerical results are provided to illustrate the free vibration behavior of the combined composite laminated conical–cylindrical shells with varying thickness.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this study, the hydrolysis of amisulbrom in buffer solutions and natural water samples were investigated. Effects of pH and temperature were tested in buffer solutions. Amisulbrom was stable in ...acidic and neutral aqueous solutions at 25°C, while quickly hydrolyzed with a half-life of 4.5 days (25°C) at pH 9.0. The kinetics rate equation was determined as
k
= 1.0234 × 10
10
exp (−61.3760/
R·T
) (R
2
= 0.9642) for hydrolysis of amisulbrom at pH 9.0. The pH, ionic strength, and solubility were important factors influencing the hydrolysis of amisulbrom in natural water samples. Furthermore, three hydrolysis products were separated and identified in buffer solution (pH 9.0) and natural water samples. A tentative transformation mechanism of amisulbrom was proposed to rationalize the formation of HPs (hydrolysis products) based on their structural identification, DFT (density functional theory), and hydrolysis profiles. Toxicity prediction using the quantitative structure–activity relationship model revealed that the HP-I, and HP-II were more toxic than the parent amisulbrom. This investigation was the first to evaluate the behavior of amisulbrom hydrolysis in aquatic systems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper focuses on the free vibration analysis of bulkhead-stiffened functionally graded open shell (FGOS) by means of the first-order shear deformation theory (FSDT) and the meshless strong form ...method. The bulkhead-stiffened FGOS is decomposed into several segments without bulkhead, and the equations of motion and boundary conditions for each segment are discretized by meshless strong form method, and the displacement components are approximated using meshfree Legendre–RIPM shape function using the combined basis of multi-quadrics (MQ) radial function and Legendre polynomials. The continuous conditions of displacement are applied at the interfaces between segments. The boundary and continuous conditions are enforced by using the artificial spring technique. The accuracy and reliability of the current method are validated by comparing the present results with those of the kinds of literature and the finite element program ABAQUS. The effects of some geometrical parameters and boundary conditions on the natural frequencies of bulkhead-stiffened FGOS are investigated through numerical examples, which may serve as benchmark data.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
A commercial formulation, 37% dispersible oil suspension (DOS) (fomesafen, clomazone, and clethodim), is being registered in China to control annual or perennial weeds in soybean fields. In this ...paper, a liquid chromatography tandem mass spectrometry method with QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation was developed for the simultaneous determination of fomesafen, clomazone, clethodim, and its two metabolites (CSO and CSO
) in soybean, green soybean, and soybean straw samples. The mean recoveries of our developed method for the five analytes in three matrices were ranged from 71% to 116% with relative standard deviations (RSDs) less than 12.6%. The limits of quantification (LOQs) were 0.01 mg/kg in soybean, 0.01 mg/kg in green soybean, and 0.02 mg/kg in soybean straw while the limits of detection (LODs) ranged from 0.018 to 0.125 μg/kg for these five analytes. The highest final residual amount of CSO
in green soybean samples (0.015 mg/kg) appeared in Anhui, and the highest in soybean straw samples was 0.029 mg/kg in Guangxi, whilst the terminal residues of fomesafen, clomazone, clethodim and CSO were lower than LOQs (0.01 mg/kg) in all samples. Furthermore, these terminal residues were all lower than the maximum residue limits (MRLs) set by China (0.1 mg/kg for fomesafen and clethodim, 0.05 mg/kg for clomazone) at harvest. Additional chronic dietary risk was evaluated using a risk quotients (RQs) method based on Chinese dietary habits. The chronic dietary exposure risk quotients were 4.3 for fomesafen, 0.12 for clomazone, and 19.3 for clethodim, respectively, which were significantly lower than 100. These results demonstrated that the dietary exposure risk of fomesafen, clomazone, and clethodim used in soybean according to good agricultural practices (GAP) was acceptable and would not pose an unacceptable health risk to Chinese consumers. These results not only offer insight with respect to the analytes, but also contribute to environmental protection and food safety.
•A engineering green TiO2/Ni-MOF-based superhydrophobic sponge was firstly fabricated.•Silane groups of ODSOSS cages endowed MOF-based sponge with superhydrophobic properties.•The coatings can ...achieve in-situ adsorption and photocatalytic degradation of pesticides.•The coated sponge can selectively and synchronously remove MPs and pesticides from high-salinity water.•The coatings have excellent absorption recyclability and salt tolerance.
Microplastics (MPs) and pesticides are becoming an intractable environmental issue due to their wide spreading and non-degradable nature, posing serious threat to ecosystem and human health. To settle such dilemma, this work reasonably designed a superhydrophobic MOF-based coated sponge (ODSOSS/TiO2/Ni-MOF/PDA@Sponge) through the combination of an environmentally friendly in-situ supersaturated coprecipitation and polysesiloxane modification method. Among them, (I) the introduction of polydopamine (PDA) not only improves the adhesion between coatings and sponge, but also enhances the growth of MOF structure through complexation. (II) The obtained Ni-MOF shows large-area microscale anthemy structure with multilayered flaky texture, forming heterogeneously hierarchical structure with the deposited TiO2 nanoparticles, which promotes photodegradation ability of TiO2 owing to great specific surface area of Ni-MOF. (III) The high specific large area Ni-MOF supplies sufficient action sites for linkage of PDA and polysesiloxane molecules with unique nanocage-like structure, thus further greatly increasing adsorption force for various pollutants. (IV) The superhydrophobicity protect the porous channels of MOF from contamination of various absorbed pollutants, while TiO2 nanoparticles effectively photodegrade the absorbed organic pollutants, endowing the sponge superior recyclability. The superhydrophobic sponge selectively rapidly and synchronously adsorbs various MPs (maintained almost 100% after 60 cycles) and pesticides (adsorption rates 71.6%–95.1%) from high-salinity water. The large-area sponge (9 cm × 6 cm × 1 cm) simultaneously removes almost 100% MPs (40 mg/L), Sudan Ⅲ (10 mg/L), kerosene (30 mL/L), and four pesticides (10 mg/L) within 1 min. Particularly, four pesticides are quickly photocatalytic degraded by the coated sponge. The free radical capture trials show that hydroxyl radicals (·OH) are the main active species of pesticide degradation. Furthermore, we reveal the negative centers where pesticide molecules are most vulnerable to ·OH attack, on basis of the charge distribution and molecular electrostatic potential (MEP) analysis. The adsorption mechanisms are carefully clarified through theoretical calculation and experimental data. This work not only provide an effective superhydrophobic candidate for MPs and pesticides removal in a broad applicable scope (especially in high-salinity wastewater), but also opens a new strategy for environmental remediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The photodegradation of fluazaindolizine in water was investigated under simulated sunlight irradiation. The effects of solution pH, humic acids (HA), nitrates (NO3−) and Fe(III) ions on photolysis ...of fluazaindolizine were studied. The results indicated that pH did not significantly affect its photodegradation. At low concentration (up to 5 mg/L), HA slightly facilitated the photodegradation of fluazaindolizine, while at high concentration (10–20 mg/L), HA inhibited its photodegradation. The presence of NO3− (0–10 mg/L) and Fe(III) (0–5 mg/L) noticeably accelerated the photodegradation of fluazaindolizine. Moreover, eleven direct transformation products (TPs) were isolated and identified by liquid chromatography quadrupole time-of-flight mass spectrometry. Density functional theory (DFT) calculation was utilized to characterize molecular property of fluazaindolizine and predict the potentiality of the possible photodegradation reaction. Ultimately, a possible transformation mechanism was proposed based on the identified TPs, degradation profiles and DFT calculation. The predominant photoproduct came from ring opening of imidazole-ring and dechlorination. Other TPs resulted from a series of photochemical reactions involving hydroxyl substitution, ring-opening, cleavage, oxidation and decarboxylation. These results were important in elucidating environmental fate of fluazaindolizine in aquatic system and further environmental risk assessment.
•Photodegradation of fluazaindolizine in aqueous solution was explored.•Eleven main TPs were isolated and identified by using LC-Q-TOF/MS.•A possible transformation pathway was proposed based on TPs and DFT calculation.•Factors affecting the fluazaindolizine photodegradation were investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Microplastics (MPs) are ubiquitous in aquatic and terrestrial environment, which pose serious threat to ecosystem and human health. Although many approaches have been developed, most of them showed ...low efficiency and long processing cycle. Herein, a cost-effective and eco-friendly coated sponge (HDTMS/CuCo-LDHs/PDA@Sponge) was successfully fabricated for the first time via the supersaturated coprecipitation methods, integrating of multistage lamellar layered hydroxides (LDHs) structure, polydopamine (PDA) adhesive layer, and hydrophobic agent. Among them, (i) the complexation of PDA can enhance the growth of CuCo-LDHs, (ii) the large surface area of CuCo-LDHs provided plentiful action sites for linkage of PDA and HDTMS molecules, thus self-strengthened the coating much more firmly, (iii) the cooperation of three buildings significantly promoted the adsorption capacity of coatings to various pollutants. The finally coated sponge showed mechanically durable, superhydrophobicity, salt tolerance, and antibacterial activity, which could efficiently and synchronously absorb MPs (polypropylene and polyethylene), dyestuff, and tiny oil, and the removal rates remained almost 100% for these pollutants. Moreover, the large-scale coated sponge (9 cm × 6 cm × 1 cm) could simultaneously adsorb almost 100% MPs (40 mg/L), Sudan Ⅲ (10 mg/L), and dodecane (20 mL/L) within 1 min. The absorption energy between the coatings and MPs were −1699 kcal/mol for PP and −932.8 kcal/mol for PE, respectively. The adsorption mechanism was ascribed to multiple forces, including electrostatic interaction, capillary attraction, hydrogen bond, p-π conjugation, Van der Waals force, lipophilicity, complexation, surface adhesion of PDA, and lipophilicity of HDTMS clusters. The developed superhydrophobic sponge will be a novel strategy to purify wastewater, especially for the high-salinity and microbial-rich marine environment.
•A robust eco-friendly Cu/Co-LDHs-based superhydrophobic sponge was firstly fabricated.•The cooperation of LDHs, PDA, and HDTMS significantly enhanced adsorption capacity of coating.•Sponge showed excellent recyclability, salt tolerance, and anti-bacteria properties.•The coated sponge could synchronously and efficiently remove MPs, dye, and oils.•Large-scale sponge adsorbed almost 100% MPs (1.5 g/L) from wastewater within 1 min.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Direct photolysis is one of the most important abiotic transformations for pesticides in the aquatic environment. In this study, direct photolysis of amisulbrom was studied under low and medium ...pressure mercury lamps at pH 4.0, 7.0 and 9.0. The result shows that the direct photolysis rates of amisulbrom in the basic solution are 2.5–2.8 times faster than in the acidic (pH 4.0) or neutral (pH 7.0) solutions under low pressure mercury lamp, while the direct photolysis rate of amisulbrom is similar in different buffer solutions under medium pressure mercury lamp. The quantum yield of amisulbrom is determined in the wavelength range of 190–400 nm. Eight main photolysis products were identified using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Based on the identified photolysis products, the density functional theory (DFT) analysis, photolysis profiles and the possible photolysis pathway of amisulbrom are proposed. The energy gap of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) for amisulbrom is 4.76 eV and it corresponds to a photon energy of 260.5 nm. The quantitative structure–activity relationship (QSAR) model is used to predict the toxicity of amisulbrom and its TPs. The Results show that TP-I (3-((6-fluoro-2-methyl-1H-indol-1-yl)sulfonyl)-1H-1,2,4-triazol-1-ium), TP-II (3-bromo- 6-fluoro-2-methyl-1H-indole), TP-III (1-((1H-1,2,4-triazol-3-yl)sulfonyl)-3-bromo-6-fluoro- 2-methyl-1H-indole) and TP-V (6-fluoro-2-methyl-1H-indole) are more toxic than their parent.
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•Direct photolysis rates of amisulbrom in the basic solution were 2.5–2.8 times faster than in the acidic or neutral solutions under low pressure mercury lamp.•Quantum yield of amisulbrom rapidly decreased as the wavelength increases, and then approaches zero at wavelength above 300 nm.•Eight main photolysis products were identified and photolysis pathway of amisulbrom was proposed.•Photolysis reaction of amisulbrom were mainly occurred on two sulfonamide functional groups and triazole ring.•Four transformation products were more toxic than the parent based on the predicted toxicity data.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The non-point source pollution of difenoconazole (DIF) has become a serious environmental issue, increasingly causes indelible damages to eco-environment and human health due to its toxicity, ...persistence, and biomagnification. An eco-friendly, cost-effective, and efficient control technology is imperative towards a cleaner and sustainable agricultural production. Herein, a dominant microflora of efficiently degrading DIF was successfully screened, and its microbial diversity was investigated. Two novel degrading strains were isolated and identified as Phyllobacterium sp. (T-1) and Aeromonas sp. (T-2). The results of growth factor optimization indicated that the degradation rates of DIF (C0 = 20 mg/L) by strain T-1 and T-2 were up to 96.32% and 97.86% within 14 d, respectively, under the optimal conditions. Moreover, there no obvious synergy between strain T-1 and strain T-2. From catalytic kinetics of enzymes, the intracellular enzyme of strain T-1 dominated the degradation of DIF (C0 = 20 mg/L) entirely with the degradation rate of 82.4% (48 h), the extracellular enzyme showed little catalytic activity. However, the degrade rates of DIF (C0 = 20 mg/L) by both intracellular and extracellular enzymes of strain T-2 were 77.99% and 26.73% within 48 h, respectively. Moreover, these enzymes remained an undiminished catalytic activity within 48 h. DIF was degraded by strain T-1 to three main transformation products (DIF-TPs 406, DIF-TPs 216, and DIF-TPs 198) undergoing hydroxyl substitution, hydrolysis, cleavage of ether bond between benzene rings, and rearrangement, while two additional products (DIF-TPs 281 and DIF-TPs 237) were generated with the biodegradation of strain T-2, excepting for DIF-TPs 406 and DIF-TPs 216, involving hydrolysis, hydroxylation, and ether bond cleavage between benzene rings. Moreover, QSAR simulation showed that the by-products were almost much lower toxicity or even non-toxic to three typical aquatic organisms (fish, daphnia, and green algae) than DIF. This study not only provides an in depth understanding of DIF bioelimination, but also be instrumental in cleaner management of DIF-contaminated soil. This study can promote the sustainable development of agriculture.
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•A dominant microflora and two novel strains of efficiently degrading DIF were obtained.•Degradation rate of DIF (C0 = 20 mg/L) in MSM exceeded 96.32% within 14 d cultivation.•DIF (100 mg/kg) in soil was degraded by 86.94% via dominant flora after 7 d application.•Biodegradation of DIF involved dioxane hydrolysis, ether bond breaking, and rearrangement.•This study provides an in depth understanding of DIF bioelimination and cleaner management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper focuses on the free vibration analysis of laminated sectorial and rectangular plates with varying fiber angle by means of the first-order shear deformation theory (FSDT) and the meshfree ...strong form method. A meshfree Legendre-radial point interpolation method (Legendre-RIPM) shape function using the combined basis of multi-quadrics (MQ) radial function and Legendre polynomials is presented. The equations of motion and boundary conditions are discretized by meshfree strong form method and the displacements are approximated using the Legendre-RIPM shape function. The accuracy and reliability of the current method are validated by comparing the results of the literature and the ABAQUS. The effects of some geometrical parameters on the natural frequencies of laminated sectorial and rectangular plates with varying fiber angles are investigated through numerical examples.
•Free vibration analysis of sectorial and rectangular plates with varying fiber angle is conducted.•Various curved and linear fibers of laminated plates are represented by fiber angle function.•A meshfree Legendre-radial point interpolation shape function is constructed.•Governing equations and boundary conditions are discretized by meshfree strong form method.•Displacement components of laminated plate are approximated by proposed shape function.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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