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Considering the efficiency and environmental issue in balloon inflating and sealing up work,an innovate design scheme cooperated by a variety of transmission structure which is ingenuity and meets the green design concept is put forward. Taking the core component cylindrical cam as an example and the parametric design analysis in its process is expounded and the mechanism is controlled to achieve precise movement by using function expression. On this basis,the optimization design based on the parameter- driven is further studied,by using the genetic algorithm in Matlab optimization toolbox and taking the resistance moment of inverse cam mechanism as objective,the model is modified and the parameter is reset by using the optimization result. The verification is carried out through the functional prototype testing and motion simulation analysis in Recur Dyn solver in UG software,and the optimized design in all the parameter driving is perfected.

Recent findings unfold that biomass materials with the micro/mesoporous structure were often treated as adsorbents for organic substances. In this work, a one‐step calcination method was adopted in the preparation of magnetic porous green bean biomass material. It has the properties of magnetism and porosity after the addition of Co(NO3)2 and high‐temperature calcination. A variety of characterizations have been operated, including energy dispersive X‐ray detector, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Brunauer‐Emmett‐Teller analysis, and so on. It has a specific surface area of 168.1611 m2/g and a pore volume of 0.1764 cm3/g. The material was used in magnetic solid‐phase extraction of three polychlorinated biphenyls: 2‐chlorobiphenyl, 4‐chlorobiphenyl, and 2,2,5‐trichlorobiphenyl. Several factors were investigated, such as material amount, eluents, adsorption time, solution pH, salinity, and reusability. Under optimized conditions, good recoveries (90.24–93.34%) were achieved with the relative standard deviation in a range from 2.30 to 4.83%. Three real water samples (tap, river, and lake water) were tested to verify the accuracy of the method. This method can be successfully used in the analysis of some polychlorinated biphenyls congeners in water. [ABSTRACT FROM AUTHOR]

Pyrethroids and neonicotinoids are widely used insecticides. However, their residues have unfavorable effects on ecological systems. Magnetic solid phase extraction is a reliable pretreatment method for a better detection of insecticides at low concentrations. In this work, amino- and carboxyl-functionalized magnetic KIT-6 were designed according to the electron-accepting groups of pyrethroid molecules and electron-donating groups with neonicotinoid structures. The characterization of these two materials was conducted using transmission electron microscopy, scanning electron microscopy, nitrogen adsorption–desorption analysis, etc. The aminated composite was applied to the magnetic solid phase extraction of pyrethroid insecticides while the carboxylic one was applied to neonicotinoids, and the adsorption effects were comprehensively compared for the first time. The material dosage, solution pH, and some factors that influenced the recovery were studied and optimized. The adsorption processes of the materials were all spontaneous and exothermic. They also fitted well with pseudo-second order kinetics and Langmuir adsorption isotherms. Both physical (pore function) and chemical (electrostatic interaction) adsorption mechanisms were present in the process. The two nanocomposites were then successfully used to enrich the two kinds of insecticides in environmental water samples. The proposed method has great application potential for insecticide monitoring in complex environmental samples. [ABSTRACT FROM AUTHOR]

The coaxiality and unbalance are the two important indexes to evaluate the assembly quality of an aeroengine. It often needs to be tested and disassembled repeatedly to meet the double-objective requirements at the same time. Therefore, an intelligent assembly method is urgently needed to directly predict the optimal assembly orientations of the rotors at each stage to meet the double-objective requirements simultaneously. In this study, an assembly optimization method for the multistage rotor of an aeroengine is proposed based on the genetic algorithm. Firstly, a spatial location propagation model is developed to accurately predict the spatial position of each rotor after assembly. The alignment process of the assembly screw holes of the adjacent rotors is considered for the first time. Secondly, a new assembly optimization strategy is proposed to select different assembly data for the specific values of the coaxiality and unbalance, respectively. Finally, a double-objective fitness function is constructed based on the coaxiality and unbalance. The simulation and experimental results show that the assembly optimization method proposed in this study can be utilized to achieve synchronous optimization of the coaxiality and unbalance of an aeroengine during preassembly. [ABSTRACT FROM AUTHOR]

Accident statistics show that more than 80% of car-to-pedestrian collisions (CPC) occur when pedestrians cross the road. It is very important to establish a finite element model with natural walking posture to study the kinematics and injury mechanism of pedestrians. In this study, a finite element model of six-year-old child pedestrian is developed with detailed anatomical characteristics and posture parameters as specified in Euro NCAP Pedestrian Human Model Certification (TB024). The numerical human body model is validated in total twelve simulations in which the pedestrian is impacted against four generic vehicle models at speeds 30, 40, 50 km/h prescribed in TB024. The Head Impact Time (HIT), Contact Force and the Trajectories of HC, T12 and AC of all twelve simulations are compared with the reference corridors provided by Technical Bulletin 024. The results indicate that the numerical human body model of a six-year-old child can be used to demonstrate the suitability of the sensing system for the range of pedestrian sizes; the timing of system deployment, and the bonnet deflection due to body loading. Furthermore, the model could be a good tool for further research on pedestrian injury mechanism and the development of pedestrian protection devices. [ABSTRACT FROM AUTHOR]

Novel magnetic CoFe2O4-embedded MIL-101(Cr) with tetramethylammonium hydroxide (CoFe2O4/MIL-101T) was prepared through the facile hydrothermal method. Tetramethylammonium hydroxide acts as a template molecule and avoids the recrystallisation of terephthalic acid. The material was applied as the adsorbent in the magnetic solid-phase extraction (MSPE) process coupled with high-performance liquid chromatography to detect the five flame retardants in environmental water samples. Several parameters affecting MSPE efficiency were systematically investigated, such as MIL-101T content, material amount, desorption solvents, adsorption time, solution pH, theoretical maximum enrichment factor (EFmax) and the reusability. Under optimised conditions, good linearities were achieved for five flame retardants with correlation coefficients R2 > 0.9961. The limits of detections for analytes at the signal-to-noise ratio of three were 0.013–0.071 μg·L−1. This method was applied to the analysis of tap, pond, lake and river waters. The recoveries were in the range of 81.5 ± 3.2–107.0 ± 2.3% with the relative standard deviations ranging from 0.11% to 8.66% in four real water samples. The adsorption mechanism was the hydrophobic interaction between the material and the analytes besides pore adsorption action of the material. [ABSTRACT FROM AUTHOR]

The aperture of KIT-6 can influence the recoveries of magnetic solid phase extraction. In this context, aperture regulated magnetic KIT-6 was prepared and characterized to improve the performance in the detection of deltamethrin and permethrin diastereomers. The novel Fe3O4@SiO2@KIT-6/130 °C nanocomposite was selected for the extraction of pyrethroid insecticides including deltamethrin, cis-permethrin and trans-permethrin. The variables influencing the extraction process such as the material dosage, adsorption time, pH, salinity of the solution, desorption solvent and enrichment factor were evaluated. The method has the advantages of low LODs, a wide linear range, good reproducibility and acceptable recoveries. Under the optimal conditions, the recoveries are between 88.5% and 95.4%. The adsorption process corresponds well with pseudo-second order kinetics and Langmuir adsorption isotherms. The process is spontaneous and exothermic on the basis of thermodynamic records. Magnetic solid phase extraction coupled with high performance liquid chromatography based on the Fe3O4@SiO2@KIT-6/130 °C nanocomposite offers an easy and sensitive way to detect trace pyrethroid insecticides in environmental water samples. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic CoFe2O4‐embedded porous graphitic carbon nanocomposites were prepared through a facile solid‐phase thermal reaction with NaCl as a template. The material was applied in the magnetic solid‐phase extraction process coupled with high performance liquid chromatography with a diode array detector to detect the trace fenpropathrin, cyhalothrin, S‐fenvalerate, and bifenthrin in different water samples. The synthesis conditions of nanomaterial including glucose concentration and calcination time on extraction performance for pyrethroid pesticides have been investigated. Different magnetic solid‐phase extraction parameters have been studied, such as the nanomaterial amount, solution pH, eluent types, adsorption time, and the reusability. Under the optimum conditions, good recoveries (80.2–110.9%) were achieved with relative standard deviations of 0.2–5.8%. There are probably hydrophobic interactions and dipole–dipole attractions between nanocomposites and the analytes. [ABSTRACT FROM AUTHOR]

The novel, stable, and environmentally friendly Ag 2 O/g-C 3 N 4 /Fe 3 O 4 nanocomposites were firstly synthesized with a combination of calcination and co-precipitation methods. The material was characterized by using transmission electron microscopy (TEM), Energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy, thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The nanocomposites were applied in the photodegradation of Rhodamine B (RhB) under visible light. The effects of the catalyst component ratio, catalyst dosage, solution pH, RhB concentration and catalyst reusability on the degradation were explored. 10 mg/L RhB can be degraded by 98.3% after 60 min under 500 W of visible light. In addition, the photodegradation kinetics and the possible reaction mechanism were investigated. [ABSTRACT FROM AUTHOR]

A child head-form is usually used to evaluate the head injury criterion (HIC) in the collision between the child pedestrian head and engine hood according to Chinese standard GB/T 24550-2009. However, intracranial response, such as principal strain and shear strain of brain tissues, cannot be evaluated by using head-form because of its poor bio-fidelity without detailed brain tissues. In this paper, a validated 6-year-old child head finite element (FE) model with detailed brain tissues was used to substitute the head-form to impact engine hood in order to investigate the effects of thickness and material properties of engine hood on head responses (HIC value, principal strain and shear strain). The results showed that the thickness of inner panel and outer panel of engine hood significantly influenced the head responses of 6-year-old child, while the effect of material properties of engine hood was not significant. The thinner engine hood could provide better protection for child pedestrian head. [ABSTRACT FROM AUTHOR]