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The eco-risk of roxarsone (ROX) was evaluated using multiple responses of earthworm biomarkers under different ROX concentrations for 28 d. With the increasing total arsenic accumulation (TAs-E), biological responses in earthworm generally showed a two-stage changes of homeostasis dysregulation and dose-dependent alterations. At the early periods, ROX stress increased the reactive oxygen species (ROS) and lipid peroxidation (LPO) in a similar manner, and apparently disrupted mitochondrial calcium ([Ca2+]m). But earthworms regulated their mitochondrial and redox homeostasis through stable mitochondrial membrane potential (MMP) and increase of ATP level, superoxide dismutase (SOD) and catalase (CAT). After 14 d, the positively correlated mitochondrial effects of ROS, [Ca2+]m, MMP and ATP were related to the behavioral inhibition of burrow length, depth and reuse rate as well as antioxidant up-regulation of Nrf2, HO-1, sod1 and cat. These results contributed possible biomarkers from the dose-dependent relationship between mitochondrial, antioxidant and behavioral responses. Multiple biological detection in earthworms can better reflect the sub-chronic ecotoxicity of phenylarsenic pollutants in soil.

Here the authors designed and synthesized three branched thiophene polymers with different effective conjugation lengths of thiophene groups, pTPBT, pTPTT, and pTPQT, mainly based on bithiophene, trithiophene, and quadruple thiophene. The electrochemical curves and theoretical calculation results reflect that the oxidation potential of polymers decreased gradually as the conjugation lengths of thiophene groups increased, which is favorable for the appearance of electrochromism. Electrochromic properties demonstrate that pTBTT displays no electrochromism, pTPTT exhibits an unstable one, while pTPQT shows an obvious stable electrochromism between yellow‐orange and blue‐violet colors. These results indicate that thiophene polymers with effective electrochromism should be the smallest conjugation length of quadruple thiophene at least. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2340–2348

Tylosin fermentation residues (TFR) pose an ecotoxicological risk through antibiotic resistant bacteria (ARBs) and their corresponding genes (ARGs). This study evaluated the ecotoxicity of TFR to soil biological activity, and further explored the mechanisms of vermicomposting to reduce the toxicological risk. The results showed that tylosin (TYL) was moderately degradable with a half-life (t1/2) of 37.5 d, inducing 28-44% inhibition rate of nitrogen transformation in soil, and the EC50 of earthworm avoidance was 880 mg/kg. The 30-d vermicomposting reduced the pH and OM content, while increased the EC and TN content, accelerated compost maturation (C/N ratio up to 20), and enriched the microbial community. ARGs were reduced by earthworm through removal of TYL (>70% degradation, t1/2 of

Arsenate (As-V) is a ubiquitous contaminant in soil as a result of excessive use of veterinary drugs and pesticides, causing enormous environmental risks. Multiple biomarkers have been used to assess the ecotoxicity of arsenic, however, the mechanisms of toxicity remain unclear. This paper describes the exposure of the earthworm (Eisenia fetida) to natural soil with different As-V concentrations for 28 days, then biomarkers from oxidative stress and burrowing behavior were quantified to evaluate As-V stress. Dynamic changes in reactive oxygen species (ROS), lipid peroxidation (MDA), adenosine triphosphate (ATP) content and antioxidant enzymes activity (Gpx, SOD, CAT) implied two stages of intensified stress responses and physiological adaptability. The transcriptional expression and regulation of antioxidant enzymes showed different responses. The mRNA expression of sod1 was up-regulated, while that of cat showed no significant change. The related regulators, nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), showed dose-dependent activation, suggesting antioxidant defense induced by Nrf2 signaling. The burrowing behavior after 14-day exposure indicated that As-V inhibited burrowing activity, especially the burrow length and maximum burrow depth. These multiple biomarkers were integrated using a biomarker response index (BRI) model, which showed significant dose-effect relationship especially on day 28, and suggested that ATP was a sensitive and representative biomarker. This study provided evidence that burrowing activity, Nrf2 and HO-1 were useful biomarkers warranting inclusion into the BRI model. Arsenic toxicity was comprehensively understood through redox homeostasis regulation, biochemical and behavioral changes, and these results suggested new strategies for soil pollutants diagnosis.

Constructing the sharing mechanism of College Students’ physical health monitoring service is not only an important resort to do a good job in college sports work, but also an important means to optimize the network system of College Students’ physique health monitoring. Starting from the importance and practical significance of the sharing mechanism in China, this paper puts forward the idea of introducing geographic information system (GIS) technology into the construction of this sharing mechanism. By means of literature, expert interview, mathematical statistics and other research methods, this paper taking 7 subordinate universities in Wuhan City as an example, makes a deep inquiry into the sharing mechanism, and considers that it is very necessary and feasible to build a sharing mechanism for physical health monitoring service of university students. And the best location of the platform is Wuhan University of Technology. The purpose is to provide feasible reference for the humanize, informatization, intellectualized and efficient construction service of College Students’ physique health monitoring service in China.

Two bilayer polymer films (pTPAT/pPHT and pPHT/pTPAT), derived from two star-shaped thiophene derivatives (TPAT and PHT) with central cores of triphenylamine and phenyl respectively, were successfully fabricated on ITO-glasses by electrochemical polymerization. The difference between the two bilayer polymer films pTPAT/pPHT and pPHT/pTPAT is just the layer configuration due to different sequential deposit orders of the pPHT and pTPAT layers during the electrochemical polymerization process. In the systems of bilayer films, the pPHT layer shows no electrochromism, a low HOMO level and a high impedance value, while the pTPAT layer shows obvious electrochromism, a high HOMO level and a low impedance value in contrast. The electrochromic properties showed that the optical contrast and cyclic stability of bilayer films are similar to those of the single pTPAT films, while the switching rate is relatively slower. Furthermore, in comparison with the pTPAT film, a higher ion-diffusion resistance was found in the bilayer film pTPAT/pPHT, and an obvious interface resistance was observed in the bilayer film pPHT/pTPAT. The existence of the pPHT layer in bilayer films may serve as a charge transport barrier and hinder the ion-diffusion or hole-injection process, depending on the layer structural arrangement in bilayer films. The investigation of the electrochromic properties of two bilayer films also provides unambiguous evidence for a fact that both ion-diffusion and charge-injection processes exerted great influences on the electrochromic switching rate of a polymer.

Arsenic (As) is widely distributed in soil and is toxic to plants, animals and humans. In this study, earthworms (Eisenia fetida) were exposed to five concentrations of sodium arsenite (5, 10, 20, 40, and 80 mg As kg−1) in farm soils for 28 d. With increasing soil As(III) concentrations, As bioaccumulation in earthworms increased (maximum bioaccumulation factor 3.77), and levels of reactive oxygen species (ROS) and malondialdehyde (MDA) were elevated. The expression of nuclear factor erythroid 2- related factor 2 (Nrf2) and heme oxygenase -1 (HO-1) were upregulated by As in a dose-dependent pattern, and reached 5.93 and 2.94 times the control values for Nrf2 and HO-1 respectively, at 28 d in the 80 mg As kg−1 soil treatment. Similarly, DNA damage, as measured in earthworm sperm using the comet assay, increased with increasing As(III) concentrations, with ‘Olive tail moment’ values in the comet assay ranging from c. 0.5 in Control to c. 3.5 at 80 mg As kg−1 soil. In contrast, activity of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), decreased. These results indicate that As(III) caused oxidative stress that resulted in damage to lipids and DNA. Nrf2 and HO-1 protein expression was demonstrated in earthworms for the first time to our knowledge, and found to be a sensitive biomarker of arsenic contamination. The presence of earthworms was also found to change the distribution of As in soil, in particular, reducing the proportion in the residual fraction and increasing the proportion in As bound to Fe-oxides. This may result in increased bioavailability of bound arsenic. Soil organic matter, NH4+-N, NO3−-N and available K were indirectly changed by the As(III) through its toxicity to earthworms. This study helps to inform future assessments and biomonitoring of soil arsenic contamination.

Exposure to ambient particulate matter (PM) links with a variety of respiratory diseases. However, compared with coarse particles (PM10) and fine particles (PM2.5), submicrometer particles (PM1.0) may be a more important indicator of human health risks. In this study, the cytotoxic and genotoxic effects of PM1.0 samples from Shanghai were examined using A549 cells, and compared with the effects of PM2.5, to better understand the health effects of PM1.0 in this area. The PM1.0 and PM2.5 samples were characterized for morphology, water-soluble inorganic ions, organic and elemental carbon, and metal elements. The cytotoxicity of PMs was measured using cell viability and cell membrane damage assays. The genotoxic effects of PMs were determined using the comet assay, and DNA damage was quantified using olive tail moment (OTM) values. The physicochemical characterization indicated that PM1.0 was enriched in carbonaceous elements and hazardous metals (Al, Zn, Pb, Mn, Cu, and V), whereas PM2.5 was more abundant in large, irregular mineral particles. The biological results revealed that both PM1.0 and PM2.5 could induce significant cytotoxicity and genotoxicity in A549 cells, and that exposure to PM1.0 caused more extensive toxic effects than exposure to PM2.5. The greater cytotoxic effects of PM1.0 can be attributed to the combined effects of size and chemical composition, whereas the genotoxic effects of PM1.0 may be mainly associated with chemical species.

A systematic methodology for formulating, implementing, solving and verifying discrete adjoint of the compressible Reynolds-averaged Navier-Stokes (RANS) equations for aerodynamic design optimization on unstructured meshes is proposed. First, a general adjoint formulation is constructed for the entire optimization problem, including parameterization, mesh deformation, flow solution and computation of the objective function, which is followed by detailed formulations of matrix-vector products arising in the adjoint model. According to this formulation, procedural components of implementing the required matrix-vector products are generated by means of automatic differentiation (AD) in a structured and modular manner. Furthermore, a duality-preserving iterative algorithm is employed to solve flow adjoint equations arising in the adjoint model, ensuring identical convergence rates for the tangent and the adjoint models. A three-step strategy is adopted to verify the adjoint computation. The proposed method has several remarkable features: the use of AD techniques avoids tedious and error-prone manual derivation and programming; duality is strictly preserved so that consistent and highly accurate discrete sensitivities can be obtained; and comparable efficiency to hand-coded implementation can be achieved. Upon the current discrete adjoint method, a gradient-based optimization framework has been developed and applied to a drag reduction problem.

A series of monomers containing tetraphenylsilane connected to different thiophenes such as thiophene, bithiophene and terthiophene were designed and synthesized and were further used to prepare the corresponding polymers via electrochemical polymerization (pSiTPTP, pSiTPBTP and pSiTPTTP). From the polymers, the effective conjugate elements were well defined as bithiophene, quaterthiophene and sexithiophene because the sp3 Si atom can block the conjugation between the thiophene units in the polymer backbone. The spectroelectrochemical results indicated that pSiTPTP is incapable of electrochromism, which may be attributed to the insufficient conjugation length of the independent bithiophene. In contrast, both pSiTPBTP and pSiTPTTP exhibited obvious electrochromic properties and furthermore, pSiTPTTP displayed a shorter switching time and better stability. Such different electrochemical behaviors can be ascribed to the looser stacking structure and lower oxidation potential of pSiTPTTP with the independent sexithiophene unit. The EIS measurements also confirmed the lower charge-transfer resistance and higher ion-diffusion rate of pSiTPTTP with the independent sexithiophene unit. Hence, we can conclude that the effects of the electrochromic behavior of the conjugation-broken polythiophene derivatives depend on the increased conjugation length of the thiophene repeating unit, in which the inadequate electrochromism with bithiophene units can change to superior electrochromic properties with increased sexithiophene units.

Lincomycin, monensin, and roxarsone are commonly used veterinary drugs. This study investigated their behaviours in different soils and their toxic effects on environmental organisms. Sorption and mobility analyses were performed to detect the migration capacity of drugs in soils. Toxic effects were evaluated by inhibition or acute toxicity tests on six organism species: algae, plants, daphnia, fish, earthworms and quails. The log Kd values (Freundlich model) of drugs were: lincomycin in laterite soil was 1.82, monensin in laterite soil was 2.76, and roxarsone in black soil was 1.29. The Rf value of lincomycin, roxarsone, monensin were 0.4995, 0.4493 and 0.8348 in laterite soil, and 0.5258, 0.5835 and 0.8033 in black soil, respectively. The EC50 for Scenedesmus obliquus, Arabidopsis thaliana, Daphnia magna and LC50/LD50 for Eisenia fetida, Danio rerio, and Coturnix coturnix were: 13.15 mg/L,32.18 mg/kg dry soil,292.6 mg/L,452.7 mg/L,5.74 g/kg dry soil and 103.9 mg/kg (roxarsone), 1.085 mg/L, 25 mg/kg dry soil, 21.1 mg/L, 4.76 mg/L, 0.346 g/kg dry soil and 672.8 mg/kg (monensin), 0.813 mg/L, 35.40 mg/kg dry soil, &gt, 400 mg/L, &gt, 2800 mg/L, &gt, 15 g/kg dry soil, &gt, 2000 mg/kg (lincomycin). These results showed that the environmental effects of veterinary drug residues should not be neglected, due to their mobility in environmental media and potential toxic effects on environmental organisms.

High quality of geometry representation is regarded essential for high-order methods to maintain their high-order accuracy. An agglomerated high-order mesh generating method is investigated in combination with discontinuous Galerkin (DG) method for solving the 3D compressible Euler and Navier-Stokes equations. In this method, a fine linear mesh is first generated by standard commercial mesh generation tools. By taking advantage of an agglomeration method, a quadratic high-order mesh is quickly obtained, which is coarse but provides a high-quality geometry representation, thus very suitable for high-order computations. High-order discretizations are performed on the obtained grids with DG method and the discretized system is treated fully implicitly to obtain steady state solutions. Numerical experiments on several flow problems indicate that the agglomerated high-order mesh works well with DG method in dealing with flow problems of curved geometries. It is also found that with a fully implicit discretized system and a p-sequencing method, the DG method can achieve convergence state within several time steps which shows significant efficiency improvements compared to its explicit counterparts.

In this paper, a high-order curved mesh generation method for Discontinuous Galerkin methods is introduced. First, a regular mesh is generated. Second, the solid surface is re-constructed using cubic polynomial. Third, the elastic governing equations are solved using high-order finite element method to provide a fully or partly curved grid. Numerical tests indicate that the intersection between element boundaries can be avoided by carefully defining the elasticity modulus.

Exposure to ambient particulate matter (PM) links with a variety of respiratory diseases. However, compared with coarse particles (PM

In this paper, the Stochastic Noise Generation and Radiation method (SNGR) is used to predict airframe noise. The SNGR method combines a stochastic model with Computational Fluid Dynamics (CFD), and it can give acceptable noise results while the computation cost is relatively low. In the method, the time-averaged mean flow field is firstly obtained by solving Reynolds Averaged Navier-Stokes equations (RANS), and a stochastic velocity is generated based on the obtained information. Then the turbulent field is used to generate the source for the Acoustic Perturbation Equations (APEs) that simulate the noise propagation. For numerical methods, timeaveraged RANS equations are solved by finite volume method, and the turbulent model is K – ε model; APEs are solved by finite difference method, and the numerical scheme is the Dispersion-Relation-Preserving (DRP) scheme, with explicit optimized 5-stage Rung-Kutta scheme time step. In order to test the APE solver, propagation of a Gaussian pulse in a uniform mean flow is firstly simulated and compared with the analytical solution. Then, using the method, the trailing edge noise of NACA0012 airfoil is calculated. The results are compared with reference data, and good agreements are demonstrated.

A computational fluid dynamics (CFD) is coupled with a computational structural dynamics (CSD) to simulate the unsteady rotor flow with aeroelasticity effects. An unstructured upwind Navier-Stokes solver was developed for this simulation, with 2nd order time-accurate dual-time stepping method for temporal discretization and low Mach number preconditioning method. For turbulent flows, both the Spalart-Allmaras and Menter's SST model are available. Mesh deformation is achieved through a fast dynamic grid method called Delaunay graph map method for unsteady flow simulation. The rotor blades are modeled as Hodges & Dowell's nonlinear beams coupled flap-lag-torsion. The rotorcraft computational structural dynamics code employs the 15-dof beam finite element formulation for modeling. The structure code was validated by comparing the natural frequencies of a rotor model with UMARC. The flow and structure codes are coupled tightly with information exchange several times at every time step. A rotor blade model's unsteady flow field in the hover mode is simulated using the coupling method. Effect of blade elasticity with aerodynamic loads was compared with rigid blade.

With the rapid development of the air-breathing hypersonic vehicle design, an accurate description of the combustion properties becomes more and more important, where one of the key techniques is the procedure of the liquid fuel mixing, atomizing and burning coupled with the supersonic crossflow in the combustion chamber. The movement and distribution of the liquid fuel droplets in the combustion chamber will influence greatly the combustion properties, as well as the propulsion performance of the ramjet/scramjet engine. In this paper, numerical simulation methods on unstructured hybrid meshes were carried out for liquid spray atomization in supersonic crossflows. The Kelvin-Helmholtz/Rayleigh-Taylor hybrid model was used to simulate the breakup process of the liquid spray in a supersonic crossflow with Mach number 1.94. Various spray properties, including spray penetration height, droplet size distribution, were quantitatively compared with experimental results. In addition, numerical results of the complex shock wave structure induced by the presence of liquid spray were illustrated and discussed.

A parallel Navier-Stokes solver based on dynamic overset unstructured grids method is presented to simulate the unsteady turbulent flow field around helicopter in forward flight. The grid method has the advantages of unstructured grid and Chimera grid and is suitable to deal with multiple bodies in relatively moving. Unsteady Navier-Stokes equations are solved on overset unstructured grids by an explicit dual time-stepping, finite volume method. Preconditioning method applied to inner iteration of the dual-time stepping is used to speed up the convergence of numerical simulation. The Spalart-Allmaras one-equation turbulence model is used to evaluate the turbulent viscosity. Parallel computation is based on the dynamic domain decomposition method in overset unstructured grids system at each physical time step. A generic helicopter Robin with a four-blade rotor in forward flight is considered to validate the method presented in this paper. Numerical simulation results show that the parallel dynamic overset unstructured grids method is very efficient for the simulation of helicopter flow field and the results are reliable.

Two dimensional hypersonic magnetohydrodynamics(MHD) flows with the chemical non-equilibrium effects are numerically simulated using upwind splitting scheme based on unstructured meshes. The governing equations are 2D MHD equations with the chemical components, where 5 species and 17 chemical reactions are considered. The AUSM scheme is implemented in the spatial discretization for the MHD equations, and an explicit 5-stage Runge-Kutta scheme is used for time integration. A loosely coupled approach is used to communicate between the MHD equations and the chemical reaction model. The computational model is a 2D blunt body, around which a dipole magnetic field is located. With hypersonic incoming flows, four different cases are numerically simulated to analyze the effects caused by the magnetic field and/or non-equilibrium chemical reactions. Numerical results are obtained and compared well with available data.

A numerical method which is based on unstructured grids to compute high-temperature ionized air radiation is described. The multi-species N-S equations are used and the chemical model includes 11 species ( O 2, N 2, O , N , NO , NO +, N +, O +, N +2, O +2, e -) and 20 reactions. For simulating thermal non-equilibrium effect, the two-temperature model is considered. The finite volume method (FVM) is used for spatial and directional discretization for the RTE on unstructured grids. The code can deal with different kinds of species and radiative bands. Particularly, the Delta, Epsilon, Beta prime and Gamma prime bands of NO are considered in this paper. The numerical results of MESES-C for hypersonic flow with high-temperature ionized radiation are shown, and compared well with the reference data and experimental data.

A numerical method for the simulation of parachute inflation process is presented in this paper. The unsteady compressible N-S equations are fully coupled with MSD (Mass Spring Damper) structure model and integrated forward in time. The CFD solver is based on an unstructured finite volume algorithm and the preconditioning technique is applied to alleviate the stiffness caused by low Mach number. The Spalart-Allmaras one-equation turbulence model is implemented to evaluate the turbulent viscosity. The whole system (fluid equations and structural model equations) is marched implicitly in time using a dual time stepping method. An overset deforming grids method is adopted in this paper to deal with the very large domain deformation during the parachute inflation process. Finally numerical test is performed to validate the robustness of this method.

In this paper we propose a second order hybrid reconstruction strategy for the fully adaptive multi-resolution scheme based on the second order finite volume method. The fully adaptive multi-resolution scheme is an adaptive grid method for solving the hyperbolic conservation laws. To improve its robustness, the third order central reconstruction is replaced by the second order hybrid reconstruction, i.e. the anti-ENO (essentially non-oscillatory) reconstruction and the ENO reconstruction have been adopted for the multi-resolution analysis and the inverse multi-resolution analysis, respectively. Several numerical examples indicate that this new hybrid reconstruction strategy is much less sensitive to the tolerance than the central reconstruction.

Previous Investigations show that it is not easy for the freestream to enter a submerged inlet with flush-mounted planar side entrance. To improve the performance of this type of inlet, three important entrance parameters, side edge angle, ramp angle, and characteristic parameter of aft lip, are introduced in this paper, and their effects on the performance of the inlet are studied by both experiments and computational fluid dynamics. Based on the results, a submerged inlet with a trapezoid entrance is designed and tested over a wide range of flow conditions. Results indicate that the designed submerged inlet can give excellent performance at the design condition and provide satisfactory performance over a wide range of test conditions. By using a numerical analysis, the influences of the freestream Mach number, the angle of attack, yaw, and Mach number at the exit on the performance and flow structure of the submerged inlet have been obtained.

New Techniques for Multi-block Hybrid Meshes with Non-uniform cells on Interface and appropriate numerical schemes is discussed. In allusion to limitations of patched grids that the cells in different sub-domains must be uniform on interface, a new method for hybrid grid decomposition with non-uniform cells(nodes) on interface is developed. In terms of theoretical analysis, the mesh generations of sub-domains are independent with each other, and this property will reduce greatly the difficulties in grid generation of complex problems, such as three-dimensional flows. Simultaneity, numerical schemes based on Jameson's method is developed to match the new grid definition. Numerical results of inviscid flow around NACA0012 airfoil are obtained, and compared with those in references.

The takeoff and the landing of an aircraft are the most dangerous phases of flight, so the study of takeoff performance and landing performance is of great importance for aircraft design and safety. In the paper, a high-precision numerical integration algorithm for evaluating takeoff and landing performance is developed, which establishes and solves the equations of dynamics during takeoff and landing process. The proposed method is capable of calculating takeoff and landing performance under different environments. To verify the current approach, all-engine operating takeoff distance, one engine failure takeoff distance, takeoff stop distance and landing distance of a certain type of plane with four engines are analyzed. It shows that the developed calculation method is reliable and effective. Based on this algorithm, a detailed analysis of the main factors affecting the takeoff and landing performance is given. The influences of altitude, temperature, takeoff and landing weight and wind speed are analyzed. Through theoretical derivation and examples verification, the proposed method will be reference for the study of takeoff and landing performance.