Particulate Matter Chemical Characteristics from a Light-Duty Diesel Engine Fueled with PODE/Diesel Blends

Meng Xin,Tian Jing,Liu Shuai,Li Ruina,Sun Jian,Liu Wenjun 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.3

To evaluate the influence of polyoxymethylene dimethyl ethers (PODE) on particulate matter (PM) chemical features, PM samples emitted from diesel fuel and PODE/diesel blends at volume ratios of 10 %, 20 %, and 30 % (P10, P20, and P30) were characterized using gas chromatography-mass spectrometry, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopic (FT-IR). Results showed that adding PODE in diesel fuel could increase the proportions of the lower carbon-atom-number components and the contents of oxygen-containing compounds in the soluble organic fractions extracted from PM samples. The ratio of oxygen to carbon (O/C), the functional groups, and the nanostructure of dry soot obtained from XPS showed that the O/C rose as the PODE volume ratio increased. The graphitization degree of dry soot decreased in the order: diesel fuel > P10 > P30 > P20. The relative content of hydroxyl functional groups exhibited the same trend, while the relative content of carbonyl functional groups exhibited an opposite trend with the graphitization degree. Moreover, according to FT-IR, both the branching degree and the relative content of hydrocarbon functional groups of aliphatics are influenced by the graphitization degree of dry soot. A turning point at P20 observed by analysis results above indicated that the chemical characteristics of PM could be affected not only by fuel properties but also by the process of fuel combustion and PM formation.

Polymorphism of Insulin-like Growth Factor Binding Protein-4 Gene in 17 Pig Breeds and Its Relationship with Growth Traits

Wang, Wenjun,Hu, Xiaoxiang,Fei, Jin,Meng, Qinyong,Li, Ning Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.10

Insulin-like growth factor binding protein-4 (IGFBP-4) is a member of the IGF super family, and regulates the action of IGFs. The polymorphism of porcine IGFBP-4 gene in 17 pig breeds (total n = 570) was detected by PCR-SSCP, and alleles A and B were detected. In these pig breeds, it was found that exotic pig breeds carried high frequencies of allele A, while Chinese native pig breeds carried high frequencies of allele B. The role of porcine IGFBP-4 was investigated in 172 F2 offspring of a $Lantang{\times}Lantang $ population. Forty eight growth traits were recorded for analyzing the association between IGFBP-4 gene polymorphism and quantitative performance traits. In this resource family, pigs with AA genotype had higher fore-body weight, bone weight of mid-body, bone weight of rear-body, fore-leg weight and rear-leg weight than those pigs with BB genotype (p<0.05); while pigs which carried BB genotype had higher back-fat thickness at C point and lard weight than those pigs with AA genotype (p<0.05); pigs with AA genotype had higher body weight than those with BB genotype; for meat quality traits, pigs with AA genotype had higher meat color than those of BB genotype (p<0.01), and pigs with BB genotype had higher marbling than those of AA and AB genotypes (p<0.01 and p<0.05, respectively).Based on these results, it is necessary to do more studies on IGFBP-4 before using the IGFBP-4 locus for the application of marker-assisted selection programs.

Buckling theoretical analysis on all-terrain crane telescopic boom with n-stepped sections

Fenglin Yao,Wenjun Meng,Jie Zhao,Zhanjiao She,Guoshan Shi,Haibo Liu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8

Differential equations for telescopic boom with n-stepped sections are established on the basis of continuous beam column theory. The recursive formula for the stability of n-stepped telescopic boom is deduced by mathematical induction. The Levenberg-Marquardt numerical optimization algorithm combined with mechanical features is used to solve the transcendental equation in the recursive formula and determine the equations when n is unknown. The length coefficients obtained using the presented methods are compared with those of the China national standard GB3811-2008 and those calculated by ANSYS 17.0. Results show that the accuracy of the LevenbergMarquardt algorithm is better than those of other algorithms. Moreover, the obtained length coefficients display a certain degree of nonlinearity. Therefore, linear interpolation is feasible in small-scale practical applications. The use of linear interpolation method leads to large error in the critical force in n-stepped section of all-terrain cranes.

The relationship between eccentric structure and super-lift device of all-terrain crane based on the overall stability

Yao Fenglin,Meng Wenjun,Zhao Jie,Shi Guoshan,Bai Yanqiang,Li Hui,Cui Yaodong 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

When the large all-terrain crane operated under ultra-high hoisting height, the stability of boom system became the key factor of the lifting capacity. The installation of eccentric structure and super-lift device could help to improve the stability of boom system. In order to achieve the best effect of growth, it was important to study the relationship between eccentric structure and super-lift device. The eigenvalue buckling analysis and geometric nonlinear buckling analysis were carried out by ANSYS for the combined boom system of 500 t all-terrain crane with tower jib when lifting load, dead weight, offset load, wind load and lifting rope force were considered. And then the influence rule of the combined relationship between the strut length, opening angle, amplitude variation angle of the eccentric structure and the strut length, opening angle, amplitude variation angle of the super-lift device on the overall stability of combined boom system was analyzed to obtain the optimum parameter combination of eccentric structure and super-lift device, which provides reference for engineering practice.

Design of a DSP-Based Real-Time Control Device for Railway Vehicle Simulation

Yuan Yuan,Wenjun Meng,Jisheng Hu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.10

A real-time control device for railway vehicle simulation is designed in this study according to the experimental requirements of a railway vehicle electric traction and electric braking system. The device uses the high-speed processing characteristic of DSP and runs on the basis of both DSP and the corresponding experimental platform. The simulation experiment for a different power grade traction system is achieved through control of the device. Full static and dynamic simulation of the operating condition of the train electric traction and braking system is attained in the case of no commissioning.

Research on average vertical velocity of rubber particles in vertical screw conveyor based on bp neural network

Sun Xiaoxia,Zhao Yang,Meng Wenjun,Zhai Yiying 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11

Incorrect formula of average particle vertical velocity can lead to incorrect derivation of the formula of conveying quantity, thus leading to incorrect design of the vertical screw conveyor. In this paper, the vertical velocity of rubber particles in vertical screw conveyor is analyzed by discrete element simulation, and the vertical velocity distribution of particle flow in vertical screw conveyor with different scale structure is analyzed. In order to reduce the computational burden of the training sample and improve the accuracy of the neural network prediction, the BP neural network method is employed. Firstly, the univariate vertical velocity of different influencing factors in microscale structure is trained and predicted, and then the average vertical velocity involving two important input variables, spiral speed and pipe diameter, is trained to get the predicted values of the average vertical velocity of neural network. Finally, the experimental verification is carried out. In this paper, the BP neural network model of the average vertical velocity of rubber particles is established, which not only provides a method for the establishment of other particle neural network models, but also avoids the repeated use of discrete element simulation, and saves a lot of time.

Research on the axial velocity of the raw coal particles in vertical screw conveyor by using the discrete element method

Zhao Yang,Sun Xiaoxia,Meng Wenjun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

An incorrect formula of the average axial speed can lead to the incorrect derivation of the conveying volume formula, which in turn can produce an incorrect design of the vertical screw conveyor. In this study, the conveying model of the vertical screw conveyor and the raw coal particle model are established. Using the discrete element method, the influence of various parameters, such as the spiral speed, filling rate, pipe diameter, and pitch, on the axial velocity of the raw coal particles is calculated, simulated, and analyzed. Corresponding to the average axial velocity distribution histogram and the derivation of the particle average axial velocity formula, a theoretical basis for the optimization design of the vertical screw conveyor is provided.

Thermo-mechanical strong coupling analysis on braking device of pipe belt conveyor

Yao Wang,Shujun Li,Wenjun Meng 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

In this study, the formula to calculate the impact factor of coupling (ξ) was proposed, considering the thermo-mechanical coupling problem of friction pairs for braking device during braking. First, a correlation between independent physical field parameters was provided by analyzing the interaction parameters of stress and temperature field. Next, the thermal analysis and thermo-mechanical strong coupling analysis were completed for friction pairs using heat transfer module and structural mechanics module of COMSOL multiphysics software on the basis of the actual operating situation of a pipe belt conveyor. The distribution and variation characteristics of the temperature and stress fields were studied with comparative analysis for braking friction pairs during braking. The mathematical expression on the impact factor of coupling (ξ) depending on braking time (t) was established. Finally, the model with thermo-mechanical strong coupling analysis was verified and compared with the thermal analysis model in terms of the measured surface temperature during braking. Simulation results revealed that the impact factor of coupling (ξ) decreased with braking time (t). However, the change rate of function initially decreased and then increased with time. An inflection point existed at t = 1.5396 s in the function ξ of t. In comparison with the small fluctuation of the simulations with thermal analysis model, the simulations with thermo-mechanical strong coupling analysis model were in good agreement with the trend of experimental results, and all the maximum relative errors were less than 4 %. Thus, the simulation with thermo-mechanical strong coupling analysis was more reliable than thermal analysis. This work could provide valuable insights in solving complex multiphysics coupling analysis.

Temperature characteristics of indentation rolling resistance of belt conveyor

Lidong Zhou,Zengfa Wu,Yongchao Li,Huiqiang Yao,Yuan Liu,Yuan Yuan,Wenjun Meng,Liangliang Han,Xueqin Cao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

In order to study the influence of temperature on the indentation rolling resistance of belt conveyor, theoretical analysis, numerical simulation analysis and experimental study of conveyor belt indentation rolling resistance with temperature characteristics were carried out in this paper, and the influence rules of different factors on the indentation rolling resistance of belt conveyor were obtained. First, the three-component Maxwell model is chosen as the viscoelastic model for the conveyor belt rubber material, and the viscoelastic modulus function based on temperature effects is constructed from the DMA experimental data fitting. Second, we introduce the one-dimensional Winkler foundation model to derive a mathematical expression for the indentation rolling resistance based on temperature properties. Then, a mathematical model of the indentation rolling resistance of a conveyor belt with temperature characteristics is developed in MATLAB and numerical simulations are performed. Finally, using the existing experimental equipment to conduct experiments, the experimental results are compared with the numerical simulation result. The results show that the theoretical numerical simulation results of the indentation rolling resistance with temperature effect presented in this paper have a consistent change trend with the experimental results; at constant temperature and constant load, the indentation rolling resistance increases with increasing band velocity; at constant temperature and constant velocity, the indentation rolling resistance increases with increasing load; at constant load and speed, when the temperature is lower than 0 °C or higher than 25 °C, the rolling resistance increases with the increase of temperature, when the temperature is between 0 °C and 25 °C, the rolling resistance decreases gradually with the increase of temperature.