Analytical Study on the Gas-Solid Suspension Flows through Sonic and Supersonic Nozzles

JianGuo Sun,G.Rajesh,Heuydong Kim(김희동) 한국추진공학회 2013 한국추진공학회지 Vol.17 No.1

A considerable deal of work has been carried out to get an insight into the gas-solid suspension flows and to specify the particle motion and its influence on the gas flow field. In this paper an attempt is made to develop an analytical model to study the effect of nozzle inlet/exit pressure ratio, particle/gas loading and the particle diameter effect on gas-solid suspension flow. The effect of the particle/gas loading on the mass flow, Mach number, thrust coefficient and static pressure variation through the nozzle is analyzed. The results obtained show that the presence of particles seems to reduce the strength of the shock wave. It is also found that smaller the particle diameter is, bigger will be the velocity as bigger particle will have larger slip velocity. The suspension flow of smaller diameter particles has almost same trend as that of single phase flow with ideal gas as working fluid. Depending on the ambient pressure, the thrust coefficient is found to be higher for larger particle/gas loading or back pressure ratio.

An Analytical Study on the Gas-Solid Two Phase Flows

JianGuo Sun,Heuy Dong Kim 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5

This paper addresses an analytical study on the gas-solid two phase flows in a nozzle. The primary purpose is to get recognition into the gas-solid suspension flows and to investigate the particle motion and its influence on the gas flow field. The present study is the primal step to comprehend the gas-solid suspension flow in the convergent-divergent nozzle. This paper try to made a development of an analytical model to study the back pressure ratio, particles loading and the particle diameter effect on gas-solid suspension flow. Mathematical model of gas-solid two phase flow was developed based on the single phase flow models to solve the quasi-one-dimensional mass, momentum equations to calculate the steady pressure field. The influence of particles loading and particle diameter is analyzed. The results obtained show that the suspension flow of smaller diameter particles has almost same trend as that of single phase flow using ideal gas as working fluid. And the presence of particles will weaken the strength of the shock wave; the bigger particle will have larger slip velocity with gas flow. The thrust coefficient is found to be higher for larger particles/gas loading or back pressure ratio, but it also depends on the ambient pressure.

A CFD Prediction of the Gas-Solid Suspension Flow through a Supersonic Nozzle

JianGuo Sun,Heuy Dong Kim,YingZi Jin 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.11

In many engineering applications such as rocket propulsions and pneumatic devices, the gas flows containing very fine solid particles are employed frequently. The presence of particles in high-speed flows results in a very complicated and interesting phenomena due to particle-turbulence interactions. It is difficult as well as costly to investigate such suspension flows. CFD approach may be a good means to get insight into the gas-solid suspension flows. The present study investigates the effect of particle diameter on the gas solid suspension flow through a supersonic nozzle. The numerical model based on the Discrete Phase Model (DPM) has been employed to simulate the particle movement. The results show that the different sizes of particle have different influence on the gas phase behavior. The structure of shock train, the separation point, and the vortex of the backflow are all changed as the particle diameter varied from small size to large size. As the particle diameter increases the flow characteristics behave differently. The separation point first moves toward the downstream, but after the critical value of the diameter, it moves back to upstream. The change of gas flow behavior in turn affects the particle distribution. When the particle diameter is too small or too big, the particle concentration at the shear layer will be weak.

Correlation between in vitro fertilization and artificial insemination in Holstein bulls

Sun Wei,Li Yunxia,Su Jie,Bao Xiangnan,Ding Rui,Zhao Gaoping,Cao Guifang,Hu Shuxiang,Wang Jianguo,Sun Qingyuan,Yu Haiquan,Li Xihe 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.12

Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI).Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI.Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%.Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding. Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI). Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI. Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%. Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding.

Influence of Solution Concentrations on Surface Morphology and Wettability of ZnO Thin Films

Jianguo Lv,Changlong Liu,Feng Wang,Zhitao Zhou,Zhenfa Zi,Yuan Feng,Xiaoshuang Chen,Feng Liu,Gang He,Shiwei Shi,Xueping Song,Zhaoqi Sun 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.2

ZnO thin films were grown on silicon substrates using a hydrothermal method. The XRD patterns show that all of the peaks can be attributed to the wurtzite structures of ZnO. The TC value of (002) plane and average crystal size increase first and then decrease with the increase of solution concentration. SEM and AFM results show that many dense hexagonal cylinder particles have been observed on the surface of the thin films, which grown at 0.08 and 0.10 mol/L. The surface roughness of the thin films deposited at 0.06,0.08, 0.10, and 0.12 mol/L are 24.5, 38.3, 32.0, and 39.4 nm, respectively. Surface wettability results show that the preferential orientation along c-axis and surface roughness contribute significantly to the hydrophobicity. The reversible switching between hydrophobicity and hydrophilicity is related to the synergy of the transition of wetting model, surface crystal structure, and surface roughness.

Facile Synthesis of Zn1-xCuxO Nanorods with a Very Broad Visible Band

Jianguo Lv,Changlong Liu,Wanbing Gong,Zhenfa Zi,Xiaoshuang Chen,Kai Huang,Feng Liu,Tao Wang,Gang He,Xueping Song,Zhaoqi Sun 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.5

Zn1-xCuxO nanorods with different Cu concentrations are prepared by a hydrothermal method. Bent and aggregated nanorods are obtained, which is attributed to centripetal surface tension of the evaporation and coagulation processes of the water film on the ZnO nanorods. The broad visible band consists of one violet, three blue,and one green emission. The violet emission is due to the transition of electrons from zinc interstitial (Zni)levels to the valance band. The three blue emissions may be attributed to the transition from extended Zni levels, which are slightly below the simple Zni level, to the valance band. The change of the green emission may be the result of competition between oxygen vacancies (VO) and zinc vacancies (VZn).

Nonparametric comparison of recurrent event processes based on panel count data

Da Xu,Jianguo Sun,Dehui Wang 한국통계학회 2016 Journal of the Korean Statistical Society Vol.45 No.2

Recurrent event processes arise in many fields including medical follow-up studies and reliability experiments and many procedures have been developed in the literature for their comparison nonparametrically (Cook and Lawless, 2007; Sun and Zhao, 2013). However, most of them are for either the complete data situation where one observes recurrent event data or the incomplete data situation where one observes panel count data with the same observation process. There also exist a couple of nonparametric comparison procedures for the panel count data situation that allow unequal observation processes, but apply only to limited situations. In this paper, we discuss the latter situation for both univariate and multivariate panel count data and propose a new type of nonparametric procedures that apply to more general situations. The proposed test statistics are shown to have asymptotic normal distributions, and an extensive simulation is conducted and suggests that they work well in practical situations. An application is also provided.

A new method for regression analysis of interval-censored data with the additive hazards model

Wang Peijie,Zhou Yong,Sun Jianguo 한국통계학회 2020 Journal of the Korean Statistical Society Vol.49 No.4

The additive hazards model is one of the most popular regression models for analyzing failure time data, especially when one is interested in the excess risk or risk diference. Although a couple of methods have been developed in the literature for regression analysis of interval-censored data, a general type of failure time data, they may be complicated or inefcient. Corresponding to this, we present a new maximum likelihood estimation procedure based on the sieve approach and in particular, develop an EM algorithm that involves a two-stage data augmentation with the use of Poisson latent variables. The method can be easily implemented and the asymptotic properties of the proposed estimators are established. A simulation study is conducted to assess the performance of the proposed method and indicates that it works well for practical situations. Also the method is applied to a set of intervalcensored data from an AIDS cohort study.

Weighted rank estimation for nonparametric transformation models with doubly truncated data

Liu Tianqing,원소휘,Sun Jianguo 한국통계학회 2021 Journal of the Korean Statistical Society Vol.50 No.1

Doubly truncated data often arise when event times are observed only if they fall within subject-specifc intervals. We analyze doubly truncated data using nonparametric transformation models, where an unknown monotonically increasing transformation of the response variable is equal to an unknown monotonically increasing function of a linear combination of the covariates plus a random error with an unspecifed log-concave probability density function. Furthermore, we assume that the truncation variables are conditionally independent of the response variable given the covariates and leave the conditional distributions of truncation variables given the covariates unspecifed. For estimation of regression parameters, we propose a weighted rank (WR) estimation procedure and establish the consistency and asymptotic normality of the resulting estimator. The limiting covariance matrix of the WR estimator can be estimated by a resampling technique, which does not involve nonparametric density estimation or numerical derivatives. A numerical study is conducted and suggests that the proposed methodology works well in practice, and an illustration based on real data is provided.

Experimental study on adsorption characteristics of Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> by datong lignite

Sihang Bao,Junzhen Di,Jianguo Yang,Donglin Wang,Juan Sun,Yanrong Dong 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3

In view of the high content of Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> in acid mine drainage (AMD), the adsorption properties of lignite for Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> were studied. The adsorption performance of lignite for Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> was revealed by combining with FT-IR, XPS and EDS. The results showed that the adsorption kinetic model of lignite for Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> conformed to the quasi-first-order kinetic model. The isothermal adsorption line fitting models of lignite for Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> were in accordance with the Langmuir model and the Freundlich model, respectively. The maximum equilibrium adsorption capacities of lignite for Cu and Zn were 67.84 mg/g and 55.5 mg/g. The adsorption process of Cu<SUP>2+</SUP> and Zn<SUP>2+</SUP> by lignite involved electrostatic, coordination and ion exchange. Under the condition of coexistence of two kinds of ion, the adsorption site of lignite had stronger binding ability to copper ions.